Valorization of fruit processing by-products 9780128171066

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Valorization of Fruit Processing By-products

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Valorization of Fruit Processing By-products

Edited by Charis M. Galanakis Research & Innovation Department, Galanakis Laboratories, Chania, Greece Food Waste Recovery Group, ISEKI Food Association, Vienna, Austria

Academic Press is an imprint of Elsevier 125 London Wall, London EC2Y 5AS, United Kingdom 525 B Street, Suite 1650, San Diego, CA 92101, United States 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom Copyright © 2020 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress ISBN: 978-0-12-817106-6 For Information on all Academic Press publications visit our website at https://www.elsevier.com/books-and-journals

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Contents List of contributors Preface

ix xi

1. Fruit processing by-products as food ingredients

1

Susanne Struck and Harald Rohm 1.1 Introduction 1 1.2 Processing of fruit by-products 2 1.2.1 Pomace processing conditions 2 1.2.2 Influence of processing on pomace composition 3 1.3 Technofunctional and physical properties of processed fruit pomace 4 1.3.1 Pomace as a source of dietary fiber and bioactive compounds 4 1.3.2 Role of dietary fiber in the human nutrition 4 1.3.3 Physical properties of processed fruit pomace 5 1.4 Application of fruit pomace in baked products 6 1.5 Pasta 9 1.6 Meat products 10 1.7 Conclusion 12 References 12

2. Apple

17

Senka Vidovic, ´ Aleksandra Tepic´ Horecki, ˇ Jelena Vladic, c, ´ Zdravko Sumi ´ Aleksandra Gavaric´ and Anita Vakula 2.1 Apple 2.2 Apple fruit processing 2.2.1 Apple fruit juice production 2.2.2 Concentrated fruit juice production 2.2.3 By-products of apple fruit juice production 2.2.4 Other apple processing—applecontaining fruit filter tea production and by-product remaining

2.3 Possibilities of application of apple processing by-products 2.3.1 Pectin 2.3.2 Valorization of apple by-products through antioxidants extraction 2.4 Conclusion References Further reading

3. Apricot

28 29 32 37 37 42

43

Estefanı´a Gonza´lez-Garcı´a, Marı´a Luisa Marina and Marı´a Concepcio´n Garcı´a 3.1 Introduction 3.2 Apricot kernel 3.2.1 Kernel oil 3.2.2 Kernel: skin and press cake 3.2.3 Essential oil 3.3 Other apricot by-products 3.3.1 Pomace 3.3.2 Thinned apricots 3.3.3 Blanching water concentrate and debittering water concentrate 3.4 Application of apricot by-products 3.5 Conclusions and future trends Acknowledgments References

4. Avocado

43 44 44 52 55 56 56 58 58 58 61 61 61

67

Huey Shi Lye, Mei Kying Ong, Lai Kuan Teh, Chew Cheen Chang and Loo Keat Wei 17 18 18 25 26

27

4.1 4.2 4.3 4.4

Introduction Nutritional composition Extraction of phytochemicals Health benefits 4.4.1 Antioxidant effect 4.4.2 Anticancer 4.4.3 Antidiabetic 4.4.4 Antiatherogenic 4.4.5 Antimicrobial effect 4.4.6 Antiinflammatory effect 4.5 Industrial applications

67 70 72 74 74 78 80 81 84 86 88

v

vi

Contents

4.6 Conclusion References Further reading

5. Berries

89 89 93

95

Petras Rimantas Venskutonis Abbreviations 5.1 Introduction 5.2 Composition of berry pomace 5.2.1 Cell wall polysaccharides, proteins, and minerals 5.2.2 Berry pomace and seed oil 5.2.3 Phytochemical composition and bioactivities of pomace 5.3 Processing of berry pomace 5.3.1 Postpressing preparation of berry pomace for processing 5.3.2 Extraction of various constituents from berry pomace 5.4 Application of berry pomace products 5.4.1 Applications of dried berry pomace 5.4.2 Applications of berry pomace extracts 5.4.3 Encapsulation of pomace ingredients 5.5 Conclusion Acknowledgments References Further reading

6. Chestnut

95 96 97 97 99 102 108 108 109 116 117 118 119 120 120 120 125

127

Diana Pinto, Nair Braga, Ana Margarida Silva, Paulo Costa, Cristina Delerue-Matos and Francisca Rodrigues Abbreviations 6.1 Introduction 6.2 Castanea sativa by-products 6.2.1 Leaves 6.2.2 Flowers 6.2.3 Shells 6.2.4 Burs 6.3 Future perspectives 6.4 Conclusion Acknowledgments References

7. Citrus fruits

127 128 128 129 133 135 137 140 140 141 141

145

Debajyoti Kundu, Mohan Das, Reddhy Mahle, Pritha Biswas, Sandipan Karmakar and Rintu Banerjee 7.1 Introduction

145

7.2 Citrus fruit waste generation and management 7.3 Valorization of citrus waste 7.3.1 Recovery of phytochemicals/bioactive compounds 7.3.2 Recovery of essential oil 7.3.3 Recovery of energy 7.4 Other value-added products 7.4.1 Production of enzymes 7.4.2 Organic acid production 7.4.3 Dietary fibers production 7.4.4 Production of single cell protein 7.4.5 Candy preparation 7.5 Bioeconomy concept in citrus waste valorization 7.6 Future scope 7.7 Conclusion References Further reading

8. Mango

146 148

148 151 152 157 157 159 159 160 160 161 162 162 162 166

167

C.H. Okino-Delgado, D.Z. Prado, Milene Stefani Pereira, Dafne Angela Camargo, Meliane Akemi Koike and Luciana Francisco Fleuri 8.1 Introduction 8.2 Mango waste 8.3 Mango peel 8.4 Mango seed 8.5 Mango waste as substrate 8.6 Prospects and conclusion References Further reading

9. Passion fruit

167 169 170 172 174 177 177 181

183

Pramote Khuwijitjaru and Khwanjai Klinchongkon 9.1 9.2 9.3 9.4 9.5

Introduction Passion fruit production Pulp and juice processing Animal feeding Valuable components from peel 9.5.1 Drying of peel 9.5.2 Pectin and pectic oligosaccharides 9.5.3 Dietary fiber 9.5.4 Passion fruit peel flour 9.5.5 Passion fruit peel extract 9.6 Valuable components from seed 9.6.1 Drying of seed 9.6.2 Seed oil 9.6.3 Piceatannol and scirpusin B

183 184 185 185 185 185 186 189 190 190 191 191 191 195

Contents

9.6.4 Other phenolic compounds and antioxidant activities 9.6.5 Seed protein 9.6.6 Antifungal protein 9.6.7 Seed fiber 9.7 Conclusion References

10. Pineapple

196 196 196 197 197 197

203

Todor Vasiljevic 10.1 Introduction 10.2 Pineapple waste utilization 10.3 Protein utilization from pineapple waste—bromelain enzyme 10.4 Bromelain extraction strategies 10.5 Membrane filtration process for bromelain extraction 10.6 Application of membrane technology in bromelain purification 10.7 Configurational considerations 10.8 Processing parameters considerations 10.9 Bromelain purity 10.10 Valorization of carbohydrates 10.10.1 Insoluble fibers—cellulose and hemicellulose 10.11 Soluble fibers—pectin and gums 10.12 Simple sugars—production of organic acids 10.13 Other value-added products obtained from pineapple waste 10.14 Conclusion References Further reading

11. Pink guava

203 204

12. Pomegranate

233 240 241 242 245 247 248

253

Shohreh Saffarzadeh-Matin 204 209 209 213 213 216 217 218 218 218 219 219 220 221 225

227

Ying Ping Chang, Kwan Kit Woo and Charles Gnanaraj 11.1 Introduction 11.1.1 About pink guava 11.1.2 Pink guava by-products 11.2 Functional properties and health-promoting effects of pink guava phytochemical constituents 11.3 Possible routes to upgrade pink guava by-products commercialization values

11.3.1 Phytochemical extraction 11.3.2 Prebiotics ingredients 11.3.3 Substrate for fermentation 11.4 Processing method to minimize the waste after extraction 11.5 Constraints and challenges in reutilizing pink guava by-products 11.6 Further research to fill the knowledge gap References

vii

227 227 228

229

231

12.1 Introduction 12.1.1 Polyphenol extraction of pomegranate waste 12.1.2 Assessment of extraction method efficiency 12.1.3 Purification and fractionation 12.1.4 Health benefits, safety assessment, and stability of pomegranate fruit extract 12.1.5 Concluding remarks References

13. Strawberry

253 254 265 268

270 272 273

281

Isidoro Garcı´a-Garcı´a, M. Carmen Garcı´a-Parrilla, Ines M. Santos-Duen˜as, Albert Mas and Ana M. Can˜ete-Rodrı´guez 13.1 Introduction 13.2 Development of new products 13.3 Using strawberries to obtain fermented products 13.3.1 Process development and quality control 13.3.2 Biotransformation of strawberry pure´e into wine and vinegar 13.4 Conclusions Acknowledgments References Further reading Index

281 285 287 287 288 296 296 297 300 301

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List of Contributors Rintu Banerjee Department of Agricultural and Food Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India Pritha Biswas School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur, India

M. Carmen Garcı´a-Parrilla Departamento de Nutricio´n y Bromatologı´a, Toxicologı´a y Medicina Legal, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain Aleksandra Gavari´c Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia

Nair Braga REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Polite´cnico do Porto, Porto, Portugal

Charles Gnanaraj Faculty of Science, Department of Chemical Science, Universiti Tunku Abdul Rahman, Negeri Perak, Malaysia

Dafne Angela Camargo Sa˜o Paulo State University (UNESP), Institute of Biosciences, Botucatu, Brazil

Estefanı´a Gonza´lez-Garcı´a Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Science, Chemical Research Institute “Andre´s M. del Rı´o” (IQAR), University of Alcala´, Madrid, Spain

Ana M. Can˜ete-Rodrı´guez Departamento de Quı´mica Inorga´nica e Ingenierı´a Quı´mica, Facultad de Ciencias, Universidad de Co´rdoba, Co´rdoba, Espan˜a Chew Cheen Chang Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia Ying Ping Chang Faculty of Science, Department of Chemical Science, Universiti Tunku Abdul Rahman, Negeri Perak, Malaysia Paulo Costa REQUIMTE/UCIBIO, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal Mohan Das Department of Agricultural and Food Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India Cristina Delerue-Matos REQUIMTE/UCIBIO, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal Luciana Francisco Fleuri Sa˜o Paulo State University (UNESP), Institute of Biosciences, Botucatu, Brazil Marı´a Concepcio´n Garcı´a Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Science, Chemical Research Institute “Andre´s M. del Rı´o” (IQAR), University of Alcala´, Madrid, Spain Isidoro Garcı´a-Garcı´a Departamento de Quı´mica Inorga´nica e Ingenierı´a Quı´mica, Facultad de Ciencias, Universidad de Co´rdoba, Co´rdoba, Espan˜a

Sandipan Karmakar Xavier Institute of Management, Xavier University, Bhubaneswar, India Pramote Khuwijitjaru Department of Food Technology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand Khwanjai Klinchongkon Department of Innovation in Food Technology, College of Health Sciences, Christian University of Thailand, Nakhon Pathom, Thailand Meliane Akemi Koike Sa˜o Paulo State University (UNESP), Institute of Biosciences, Botucatu, Brazil Debajyoti Kundu Department of Agricultural and Food Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India Huey Shi Lye Department of Agricultural and Food Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia Reddhy Mahle Department of Agricultural and Food Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India Marı´a Luisa Marina Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Science, Chemical Research Institute “Andre´s M. del Rı´o” (IQAR), University of Alcala´, Madrid, Spain ix

x

List of Contributors

Albert Mas Departamento de Bioquı´mica i Biotecnologı´a, Facultad de Enologı´a, Universitat Rovira i Virgili, Tarragona, Espan˜a C.H. Okino-Delgado Agronomic Engineering, University Center of Rio Preto, Sa˜o Jose´ do Rio Preto, Brazil

Susanne Struck Chair of Food Engineering, Insitute of Natural Materials Technology, Technische Universita¨t Dresden, Dresden, Germany ˇ Zdravko Sumi´ c Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia

Mei Kying Ong Department of Agricultural and Food Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia

Lai Kuan Teh Department of Biomedical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia

Milene Stefani Pereira Sa˜o Paulo State University (UNESP), Institute of Biosciences, Botucatu, Brazil

Aleksandra Tepi´c Horecki Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia

Diana Pinto REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Polite´cnico do Porto, Porto, Portugal

Anita Vakula Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia

D.Z. Prado Sa˜o Paulo State University (UNESP), Institute of Biosciences, Botucatu, Brazil

Todor Vasiljevic Institute for Sustainable Industries and Liveable Cities, Victoria University, Melbourne, VIC, Australia

Francisca Rodrigues REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Polite´cnico do Porto, Porto, Portugal

Petras Rimantas Venskutonis Department of Food Science and Technology, Kaunas University of Technology, Kaunas, Lithuania

Harald Rohm Chair of Food Engineering, Insitute of Natural Materials Technology, Technische Universita¨t Dresden, Dresden, Germany

Senka Vidovi´c Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia

Shohreh Saffarzadeh-Matin Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran Ines M. Santos-Duen˜as Departamento de Quı´mica Inorga´nica e Ingenierı´a Quı´mica, Facultad de Ciencias, Universidad de Co´rdoba, Co´rdoba, Espan˜a Ana Margarida Silva REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Polite´cnico do Porto, Porto, Portugal

Jelena Vladi´c Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia Loo Keat Wei Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia Kwan Kit Woo Lee Kong Chian Faculty of Engineering and Science, Department of Chemical Engineering, Universiti Tunku Abdul Rahman, Negeri Perak, Malaysia

Preface The global fruit processing industry has been growing steadily over the last few years due to population growth, consumers’ eating patterns targeting healthier products, and finally advances in supply chain management and production processes. At the same time, fruit processing results in significant amounts of by-products that are typically given as animal feed or discharged into the environment. This practice cannot be continued within the bioeconomy framework of our times. In particular, the urgent need for sustainability within the fruit industry has turned the interests of research toward investigating the handling of these by-products from another perspective, for example, by adapting more profitable options, utilizing contained antioxidants, etc. Subsequently there is a need for a new guide covering the latest advances in this direction. Food Waste Recovery Group (www.foodwasterecovery.group of ISEKI Food Association) has organized different training and development actions in the field of food and environmental science and technology, including teaching activities (e-course, reference module, training workshops, and webinars), literature materials, experts’ database, several news channels for dissemination of knowledge, and an open innovation network, with the aim to bridge the gap between academia and the food industry. In addition, the group has published books dealing with food waste recovery technologies, different food processing by-products’ valorization (e.g., from olive, grape, cereals, coffee, meat, etc.), sustainable food systems and saving food, sustainable water and wastewater processing, innovations in the food industry and traditional foods, nutraceuticals and natural product pharmaceuticals, and nonthermal processing, as well as the targeting of functional compounds such as polyphenols, proteins, dietary fiber, and carotenoids. Following on from these efforts, the current book aims to indicate the alternative solutions for the upgrading of processing by-products of different fruits, as well as denoting their industrial potential as a source for the recovery of bioactive compounds and their reutilization in different sectors (e.g., food, beverage, nutraceutical, and cosmetic industries). The ultimate goal is to support the scientific community, professionals, and enterprises that aspire to develop real, high-scale industrial applications. It focuses on the most recent advances in the field, while also analyzing the potential of already commercialized processes and products. The book fills the existing gap in the current literature by providing a guide for all the involved stakeholders, professionals, and technologists who are active in the field and are trying to optimize the performance of fruit processing industries and reduce their environmental impact. The book consists of 13 chapters. Chapter 1, Fruit processing by-products as food ingredients, introduces the subject of the book by providing a short overview on the processing and composition of fruits’ pomace. By highlighting the importance of pomace as a nutritionally valuable material, the chapter reviews the incorporation of fruit pomace in selected foods. Emphasis is especially given to bakery products, extruded cereal products, pasta, and meat products. The remaining chapters of the book deal with different fruit processing by-products in chapters placed in alphabetic order. Chapter 2 deals with apples. Apple juice production generates approximately 25% of by-products including pomace, peel, and seeds. Traditional applications of apple processing by-products typically concern composting or crude feed. Nevertheless, owing to its high carbohydrate content, apple pomace can be used as a substrate for the production of various value-added products such as organic acids, enzymes, and ethanol. The application of apple pomace in the production of biscuits and related products due to its high pectin content is also reported. Chapter 3 discusses the by-products (mainly stone) of apricot processing. The apricot is a stone fruit belonging to the Prunus genus highly consumed worldwide. The apricot kernel is a great source of oil, mainly composed of fatty acids, especially unsaturated fatty acids. This oil also presents high concentrations of triterpenoids, carotenoids, vitamin E active compounds, phytosterols, and polyphenols. Apricot kernels are also a source of proteins, peptides, and essential oil. Chapter 4 deals with the nutritional profiles, the extraction of phytochemicals, and the industrial applications of avocado and its by-products (seed, pulp, and peel). Avocado has been recognized as a nutritionally valuable tropical fruit that has a variety of health-promoting effects and nutrients. Past studies have revealed that avocado possesses xi

xii

Preface

antioxidant, anticancer, antidiabetic, antiatherogenic, antihypertensive, antiinflammatory, and antimicrobial effects. Whole avocado and its derivatives have been used in various industries as a main ingredient and have been processed into a number of food products and skin care products, while avocado’s processing by-products have not been much investigated yet. Chapter 5 reviews the results of investigations concerning pomace from berries. Berries are among the richest sources of health-beneficial phytochemicals, and their cultivation and consumption are steadily increasing. Juice production from berries generates large amounts of press cake (pomace), a by-product of berry processing, which retains large fractions of various berry components, including valuable phenolic compounds, seed oils, dietary fiber, minerals, and others. Currently, considerable quantities of pomace are discarded as waste, causing both the loss of valuable nutrients and environmental pollution. It is evident that berry pomace should be used more efficiently, for example, for the recovery of valuable constituents and the development of ingredients for human nutrition and other applications. During chestnut processing, a large amount of waste material is generated. Chapter 6 provides knowledge on the types of chestnut by-products produced (e.g., leaves, flowers, shells and burs), their chemical compositions, and biological activities, prior to discussing their possible applications in the pharmaceutical, food, or cosmetics sectors. Waste from the citrus processing industry, generated after juice extraction, comprises about 50% of the wet mass of citrus fruits, of which about 50% is peel waste. With the increasing size of the citrus industry, colossal volumes of waste are being released constantly into the environment. Chapter 7 highlights the valorization of citrus waste through value-added product recovery and energy production, which is gaining more impetus under the umbrella of the biobased economy. Chapter 8 deals with the mango, which is among the most consumed fruits worldwide. Indeed the consumption of processed mango products has grown, and consequently the generation of mango waste has also grown, since the pulp (the main product) corresponds to approximately half of the fruit mass. Mango by-products can be used by the final consumer or as food ingredients in diverse segments such as foods, pharmaceuticals, fine chemicals, cosmetics, cleaning products, and personal hygiene products. Chapter 9 discusses the valorization of passion fruit by-products, which have attracted manufacturers and researchers worldwide due to the fact that they contain valuable and health-beneficial components. Current by-product valorizing schemes that have been already commercialized include the extraction of seed oil and the further fractionation of unsaponifiable fraction for cosmetic purposes. In addition, seed extracts containing functional phenolic compounds, piceatannol, and scirpusin B are also in the market. At the same time a number of research works on the peel have revealed various possibilities for the extraction of pectin and other bioactive compounds. Chapter 10 focuses on the extraction of valuable compounds from pineapple on-farm and from processing waste for food and therapeutics applications. An emphasis is given to more environment-friendly and commercially viable technologies—mainly membrane-based extraction techniques. The high carbohydrate content (55%) and presence of a highly valuable enzyme, bromelain, in pineapple waste makes it an appropriate substrate for a simple extraction of these valuable compounds or feasible bioconversions into xylitol, xylooligosaccharides, lactic acid, succinic acid, and others, which all have potential applications in the food industry. Guava is a popular tropical fruit eaten either fresh or in a preserved or processed form and it is also a good source of dietary fiber and natural antioxidant compounds. The fleshy edible portion of guava fruit only constitutes about 50% of the whole fruit, while the peel (20%) and seed core (30%) are taken to a landfill site as waste. Chapter 11 discusses possible routes to upgrade the commercial values of pink guava by-products by applying different extraction techniques to recover valuable phytochemicals. The manufacturers of processed guava may include by-products processing in one of their production lines in order to generate diverse products or ingredients within a “zero-waste” concept and to achieve a more sustainable approach. Chapter 12 provides an updated overview of the polyphenolic extraction of pomegranate waste, including various extraction process variables, conventional and nonconventional extraction methods, and extraction process optimization. Additionally, the purification and fractionation of polyphenolic extracts, including small-scale isolation, selective adsorption
desorption, and membrane filtration process are covered, too. Furthermore, the health benefits, safety assessments, and improvements in stability of the extracts are reviewed. The strawberry’s instability in seasonal markets, high perishability, and stringent quality criteria can lead to substantial surpluses with highly adverse impacts on social and economic conditions in the production areas, and also on the environment by the effect of such surpluses constituting highly polluting waste. Chapter 13 discusses the production of new beverages and condiments by mixing two essential ingredients obtained in parallel by the biotransformation of strawberry pure´e. Pure´e can be used to obtain strawberry vinegar through alcoholic fermentation and subsequent

Preface

xiii

acetification, as well as gluconic acid by the selective bioconversion of glucose while preserving the fructose content of the substrate. In conclusion, this book addresses researchers, consultants, and new product developers working in the food and fruit processing industry. It could be utilized by University libraries, Institutes, and Agencies worldwide as a textbook and ancillary reading in undergraduate and postgraduate level multidiscipline courses dealing with agriculture, bioresource technology, and food science. At this point, I would like to thank all the authors for accepting my invitation to contribute to this book. Their adaption to editorial guidelines and project’s timeline are highly appreciated. In fact I consider myself fortunate to have had the opportunity to collaborate with different international experts from Australia, Brazil, India, Iran, Lithuania, Malaysia, German, Portugal, Spain, and Thailand. I would also like to thank the acquisition editors Nina Bandeira and Nancy Maragioglio, the book manager Katerina Zaliva, as well as Elsevier’s production team for their assistance during editing and the publication process. Finally, I have a message for all of you, the readers. Collaborative book projects contain hundreds of thousands of words and therefore they may contain errors or gaps. I will wait for your instructive comments or even criticism, so please do not hesitate to contact me in order to discuss any issues regarding the valorization of fruit processing by-products. Charis M. Galanakis1,2 1

2

Research & Innovation Department, Galanakis Laboratories, Chania, Greece, Food Waste Recovery Group, ISEKI Food Association, Vienna, Austria

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Chapter 1

Fruit processing by-products as food ingredients Susanne Struck and Harald Rohm Chair of Food Engineering, Insitute of Natural Materials Technology, Technische Universita¨t Dresden, Dresden, Germany

Chapter Outline 1.1 Introduction 1.2 Processing of fruit by-products 1.2.1 Pomace processing conditions 1.2.2 Influence of processing on pomace composition 1.3 Technofunctional and physical properties of processed fruit pomace 1.3.1 Pomace as a source of dietary fiber and bioactive compounds

1.1

1 2 2 3 4

1.3.2 Role of dietary fiber in the human nutrition 1.3.3 Physical properties of processed fruit pomace 1.4 Application of fruit pomace in baked products 1.5 Pasta 1.6 Meat products 1.7 Conclusion References

4 5 6 9 10 12 12

4

Introduction

In many cases, and depending on the target commodity, the processing of fruits results in certain amounts of by-products. The respective quantities are close to zero when, for example, berries are processed to jam, but may be around 5%
10% when it comes to peels of apples or pears that are used for the production of fruit sauces, and 20%
30% when juice is extracted from the raw material. Sustainable and integrated value chain management calls for a further use of these by-products, commonly denoted as pomace, to avoid their loss. Potential but uninspired uses are as soil fertilizer, as animal feed, or as substrate for bioenergy generation. Even for these types of utilization, limitations have to be considered because of the high acidity of the pomace, its high content of phytochemicals, and the low amount of digestible energy. Recycling methods that add value to fruit processing residues are therefore of great interest, and it can be expected that the overall profit from fruit processing will be increased by an efficient and sustainable waste stream management. Innovative utilization methods must therefore address the usability of fruit processing residues as value-adding food ingredients, either as a whole or after the extraction of high-value compounds. Depending on the raw material, residues from fruit processing may contain high amounts of bioactive compounds, including dietary fiber, which therefore makes these residues an attractive source of nutrients. Dietary fiber refers to polymeric carbohydrates with at least 10 monomeric units which are not digested in the human small intestine. They either dissolve in water (soluble dietary fiber) and are metabolized in the large intestine, or they are insoluble and therefore mainly excreted (Viebke et al., 2014). In comparison to fiber from cereals, the amount of soluble dietary fiber in fruit pomace is significantly higher (Sudha, 2011). Many health-promoting effects have been attributed to these bioactive compounds. Some of these that have already been reported are the reduction of risk of cardiovascular diseases and cancer through their antioxidant and antiinflammatory activities that, in turn, reduce oxidative stress (Basu et al., 2010; Mazzoni et al., 2016; Rodriguez-Mateos et al., 2013), and the modulation of intestinal microbiota (Vendrame et al., 2011). Koutsos et al. (2015) summarized in vitro, animal, and human intervention studies that analyzed the influence of apple compounds on gut microbiota and on the risks of cardiovascular diseases. They concluded that significant effects are evident with respect to lipid metabolism (i.e., reduction in total cholesterol), and with respect to metabolites produced in the gut. Teixeira et al. (2014) focused on wine making by-products and reviewed the biological activity of Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00001-0 © 2020 Elsevier Inc. All rights reserved.

1

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Valorization of Fruit Processing By-products

functional compounds such as phenolic acids, flavonoids, and stilbenes. As many phenolic compounds are located in the skin and seed fractions of fruits, the respective by-products are rich in stilbenes and flavonoids. Some of the latter, namely the anthocyanins, are responsible for the color of fruits and their high antioxidant capacity (Laroze et al., 2010). Consequently, the incorporation of bioactive compounds from fruit processing residues in foods increases the supply of valuable nutrients. For that the development of attractive products is necessary, as is the communication of the proposed effects to the consumer.

1.2 1.2.1

Processing of fruit by-products Pomace processing conditions

The conventional procedure for the production of fruit juice from, for instance, apples, pears, or different berry varieties usually starts by washing the raw materials and removing foreign bodies. It then comprises the crushing of fresh or frozen fruits to mash, heating the mash to 40 C
50 C and, in many cases, treating the mash with depectinizing enzymes (pectin esterases, polygalacturonases, and/or pectin lyases) for a period of approximately 1
3 h. This helps to break down cell wall structures and to disrupt the highly viscous pectin gel that forms during mashing (Hilz et al., 2005), so that juice yield during subsequent pressing is enhanced by 1%
3%. Additionally, more polyphenols are extracted with the juice which, especially in the case of dark fruits, lead to a more intense color that is frequently associated with a higher juice quality by the consumer. The next step is separating the juice from the solid cell materials by using belt presses, basket presses, or Bucher horizontal presses, the selection of which largely depends on the required capacity. For instance, belt presses are more versatile but a severe risk of juice oxidation must be considered. Subsequently the juice is declouded by disk stack or decanter centrifuges and finally pasteurized to assure an appropriate shelf life. In the case of citrus processing, the technological scheme is somewhat different: the most important step is the recovery of the juice from the whole fruit, realized by extractors with different working principles. Remnants from the processing of different types of citrus fruits—these are mainly used for the production of citrus pectin (Wang et al., 2015)—will not be considered further in this chapter. The pressing residues that remain after fruit extraction contain 50%
80% moisture, and are consequently highly susceptible toward microbial spoilage, especially by yeasts and molds. Factors that contribute to the residual moisture content of the pomace are, among others, the fruit variety itself, any depectinization of the mash, and the processing conditions during pressing (method, pressure). In the cases where the remaining pomace is considered for further use in human nutrition, immediate processing to reduce pomace moisture is essential. Recent reviews related to pomace utilization cover advances in pectin production (Adetunji et al., 2017; Grassino et al., 2018), the use of fruit byproducts as edible films (Otoni et al., 2017), the use of these by-products as novel functional ingredients for foods and nutraceuticals (Lai et al., 2017; Quiles et al., 2017; Schieber, 2017; Sharma et al., 2016), the extraction and analysis of the polyphenols (Struck et al., 2016c), but also the application as heavy metal chelating agents for wastewater treatment (Renu et al., 2017). Because of its content of approximately 15%, the traditional utilization of apple pomace is for the production of raw pectin. In brief, hot acidic extraction of soluble materials is followed by their concentration and the subsequent pectin precipitation and purification. The composition of berry pomace largely depends on the berry cultivar. In blueberries, the mass fractions for skin and seeds are 19% and 1.5%, respectively (Lee and Wrolstad, 2006). After juice extraction, the pomace also contains residual stems, and some wooden parts and leaf fragments remaining from harvesting. For black currant pomace, these constituents account for approximately 6% of the fresh mass, whereas seeds were reported to comprise the main fraction (i.e., 55%) of the dried pomace (Hilz et al., 2005; Sojka and Krol, 2008). For the production of a nonperishable berry powder intended to be brought back into the food value chain, the most important processing step is immediate drying after juice pressing, followed by milling and fractionation. Potential methods for pomace drying include conventional hot-air convection drying, low-temperature vacuum drying, freeze-drying, infrared drying, and microwave drying (the latter two are often combined with convection drying under vacuum). Convection drying of fruit pomace is usually performed in a temperature range of 50 C
80 C at ambient pressure, or at reduced temperature and pressure (e.g., Reque et al., 2014; Sojka et al., 2013). Processing conditions during drying exhibit a significant influence on product characteristics such as appearance, color, and porosity, and also on the content of bioactive compounds. Garau et al. (2007) observed a decreased water retention capacity, and reduced fat adsorption and solubility with increasing drying temperature of by-products from orange processing. In the production of Aronia powder from juice, convection drying resulted in a more intense and darker color of the powder than freeze-drying or spray-drying (Horszwald et al., 2013). Zielinska and Michalska (2018) compared moisture diffusion coefficients obtained by the mentioned techniques, and

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reported the lowest degradation of bioactive constituents when microwave-assisted drying was applied. Microwave radiation induces the development of thin pores in the sample, so that moisture release is facilitated, drying time is decreased, and product texture is altered (Bo¨hm et al., 2006). Depending on the composition and on further requirements, the dried material is then either subjected to milling—in this case, the seeds remain in the material—or it is separated by sieving prior to the milling step. This affects the fat content of the pomace; milling with seeds is helpful in increasing the beneficial properties of berry powder as the seeds’ breakdown liberates health-promoting compounds (that are normally excreted undigested inside the hard seeds; Helbig et al., 2008), but also for its potential field of application (Reissner et al., 2019). By means of micromilling Mayer-Miebach et al. (2012) demonstrated an enhanced extractability of phenolic compounds from chokeberry pomace and an improved antioxidant capacity of the resulting nanosized material. The particle size of dietary fiber powder is also known to influence its hydration properties, as a decreased particle size is usually linked to a lower water-binding capacity; however, depending on the resulting particle size distribution, contrary effects have also been observed. A final processing step could therefore be fractionation, or the separation of the seeds with the aim of using them for the subsequent extraction of seed oil (Abrahamsson et al., 2015).

1.2.2

Influence of processing on pomace composition

Methods and conditions applied during fruit processing significantly influence the composition of the remaining pomace and its functional and technofunctional properties. It has already been shown that processing usually does not change the content but may affect the physiological functionality of the fiber in the small or large intestine. The underlying changes in dietary fiber composition can be induced by hydrolytic enzymes or by chemical degradation that is, for example, triggered by the thermal impact. A molecular mass reduction of dietary fiber components by chemical degradation is responsible for a viscosity decrease and a reduced hydration capacity, and changes their metabolic effects (Nyman, 2003). The influence of thermal energy on cell wall material may induce lignin depolymerization and therefore the formation of free hydroxyl and carbonyl groups (Wawer et al., 2006). Enzymatic mash treatment has been shown to increase the swelling capacity but to decrease the water-binding capacity of milled pomace (Alba et al., 2017; Kosmala et al., 2010). This was attributed to the fact that depectinizing enzymes degrade parts of the cell wall fragments and hence loosen their structure. Phenolic compounds are also influenced by processing conditions, either because they decompose at higher temperature ( . 90 C), or because they become more easily extractable after enzymatic treatment (Holtung et al., 2011; Koponen et al., 2008). Using blueberry and grape pomace as demonstration objects, Khanal et al. (2010) analyzed the influences of drying temperature and time and showed that procyanidin and anthocyanin contents did not change when the pomace was warmed to 40 C, but heating to above 60 C reduced the respective contents; the highest loss of anthocyanins (52%) was observed after subjecting the pomace to 125 C in a forced-convection oven (Fig. 1.1). Heating of chokeberry pure´e up to 100 C for 15 min had no significant influence on its procyanidin content; it seems that moisture content and drying method and time are the prominent factors that influence polyphenol degradation but the extractability of

FIGURE 1.1 Effect of heating temperature in a forced-air oven on total anthocyanin content (mg cyanidin 3-glucoside equiv./kg dry matter) of blueberry and grape pomace. Each data point indicates means 6 SEM. Data points with different upper case letters indicate significant differences (P , .05) between grape and blueberry pomace, while those with different lower case letters indicate the differences (P , .05) caused by different heating conditions within each pomace type. From Khanal, R.C., Howard, L.R., Prior, R.L., 2010. Effect of heating on the stability of grape and blueberry pomace procyanidins and total anthocyanins. Food Res. Int. 43, 1464
1469, with permission from Elsevier.

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Valorization of Fruit Processing By-products

polyphenolic compounds also has an influence (Mayer-Miebach et al., 2012; White et al., 2011). Extrusion was also reported to affect the polyphenols content of pomace. Khanal et al. (2009) showed a reduction of the total amount of anthocyanins in blueberry pomace of 33%
42%, and an increase of monomeric and dimeric procyanidins which are more easily absorbed in the human intestine and therefore exhibit higher bioactivity. According to White et al. (2010), the effects of extrusion temperature depend on the chemical characteristics of the respective compounds: chemical degradation is an issue but, in the case of more heat-stable compounds, such as flavonols, the disruption of the pomace matrix that facilitates the improved extractability of the molecules should also be taken into account. Another factor that may affect the content of bioactive compounds in pomace is enzymatic degradation that may occur after pressing by endogenous enzymes such as polyphenoloxidase and glucosidase. Polyphenoloxidase is mainly responsible for color changes caused by the degradation of phenolic compounds, but activity of these enzymes varies considerably between different fruits. Additionally, flavonols have been reported to be less susceptible to enzymatic degradation than anthocyanins (Skrede et al., 2000). Blanching may be considered for the inactivation of endogenous enzymes; however, White et al. (2011) stated that in the case of cranberries blanching resulted in a significant loss of anthocyanins.

1.3 1.3.1

Technofunctional and physical properties of processed fruit pomace Pomace as a source of dietary fiber and bioactive compounds

The residues from fruit juice processing contain high amounts of dietary fiber and bioactive compounds. Dietary fiber refers to plant cell walls consisting of complex polysaccharides, mainly cellulose, hemicellulose, and pectic substances that are resistant to pancreatic enzymes. As already mentioned, bioactive compounds have been linked to a number of health-promoting effects. For instance, a risk reduction with regards to cardiovascular diseases and cancer via their antioxidant and antiinflammatory activity that, in turn, reduces oxidative stress has been addressed (Chu and Liu, 2005; Mazzoni et al., 2016). Khanal et al. (2009) pointed out that 25%
50% of blueberry procyanidins remain in the pomace after juice extraction, indicating a loss of valuable nutritional compounds when pomace leaves the food chain. Additionally, many phenolic compounds located in the skins and seeds are retained in the pomace (White et al., 2010). Pomaces from different fruit varieties were suggested as possible sources of dietary fiber for human nutrition. For instance, apple pomace has a well-balanced proportion of soluble and insoluble dietary fiber and contains bioactive compounds such as polyphenols, flavonoids, and carotenes. Depending on the apple variety, the fiber content of the pomace varies from 35.5 g/100 g dry matter for Golden Delicious to as high as 89.9 g/100 g for Liberty (Figuerola et al., 2005; Sudha, 2011). By-products from citrus juice production also have a high potential as food ingredients since they are rich in pectin, a food additive of interest because of its specific gelling properties. Some orange varieties such as Valencia have substantial dietary fiber content (64.3 g/100 g dry matter), while others such as Navel or Salustiana have lower dietary fiber content (35.4
36.9 g/100 g; Figuerola et al., 2005; Grigelmo-Miguel and Martı´nBelloso, 1999). Grape pomace is a rich source of bioactive compounds such as phenolic compounds and fatty acids. The fiber composition of grape pomace may be influenced by variety, culture characteristics, and wine processing procedures (Iora et al., 2015). The usual range of dietary fiber in grape pomace is 50
75 g/100 g dry matter. Pomaces of peach (Grigelmo-Miguel and Martı´n-Belloso, 1999), plum (Milala et al., 2013), grapefruit (Wang et al., 2015), guava (Matias et al., 2005), kiwi, and pear (Martin-Cabrejas et al., 1995) were also subject of scientific studies.

1.3.2

Role of dietary fiber in the human nutrition

Although fiber is not hydrolyzed in the human small intestine, a protective effect of dietary fiber against the diseases that are predominant in Western developed countries is well known, for instance in connection with colorectal cancer, coronary heart disease, obesity, and diverticular disease. Fiber consumption is associated with a reduction in total serum cholesterol and low-density lipoprotein cholesterol levels, and the modification of glycemic and insulinemic responses (Blackwood et al., 2000). According to the physical, functional, and chemical properties, dietary fiber can be classified as soluble or insoluble dietary fiber. Soluble dietary fiber, such as pectins, gums, inulin-type fructans, and some hemicelluloses, forms viscous gels in water and can be fermented by microbiota in the large intestine. Insoluble dietary fiber that leaves the intestine in an almost unchanged form comprises lignin, cellulose, and some hemicelluloses (Lattimer and Haub, 2010).

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Some physicochemical properties of dietary fiber are linked to their gastrointestinal function. These properties include viscosity, water- and fat-binding capacities, gel formation, swelling, the binding of organic molecules, and fermentation (Viuda-Martos et al., 2010). An increase of viscosity in the gastrointestinal tract triggered by dietary fiber consumption slows the transit velocity through the small intestine and therefore prolongs gastric passage. Dietary fiber has the ability to retain water due to its hydrophilic nature. Therefore stool bulking is increased and subsequently the volume of the intestinal contents is increased as well. This will lower the concentration of nutrients in the aqueous phase and slow down their absorption. Binding of bile acids by dietary fiber is the mechanism most probably responsible for their hypocholesteremic effect (Blackwood et al., 2000; Schneeman, 2001). Concerning carbohydrate metabolism, dietary fiber affects the rate and extent of starch degradation and glucose absorption. The effect of dietary fiber in that context might result from the alteration of viscosity in the small intestine, thus leading to a reduced accessibility of starch granules by amylases (Brennan, 2005). In vitro digestion methods that mimic the oral, gastric, and small intestinal phases help in the study of gastrointestinal behavior of foods. By doing so, the influence of dietary fiber on the glycemic index of foods can be analyzed (Minekus et al., 2014). The recommended fiber intake for adults is 25 g/day for a 2000 kcal diet, whereas the average dietary fiber intake for adults varies from 16 to 29 g/day for countries of the European Union (EFSA, 2010). Many commonly consumed foods are low in dietary fiber; higher fiber contents can be found in foods such as whole grain cereals, legumes, and dried fruits (Slavin, 2013). In this context the addition of processed fruit pomace to food formulations seems promising to aid in increasing the dietary fiber content of foods and thus provide additional health benefits (Rohm et al., 2015).

1.3.3

Physical properties of processed fruit pomace

The water-binding capacity of dietary fiber is of considerable importance for food applications because it impacts not only the physiological functionality of the food, but also the product yield, ingredient functionality, and shelf life (Rosell et al., 2009). As regards physiological functionality, the water-binding capacity may be used to predict the ability of fiber to increase stool weight and the induction of colonic fermentation (Auffret et al., 1994). In addition, the quantification of respective properties allows drawing of conclusions with respect to possible food applications. For example, fiber with a high fat-binding capacity might be best applied to stabilize fat in emulsion-based products, whereas a high water-binding capacity can be linked to decreasing syneresis in hydrogels, or altering food viscosity and texture (Eim et al., 2008; McKee and Latner, 2000). Hydration properties are usually characterized either by the water-binding capacity which is determined by applying external stress (centrifugation, compression, suction pressure), the water-holding capacity which is defined as water uptake at a given external chemical potential of water without application of external stress (sorption isotherms, Baumann apparatus, freezing point method), or the swelling capacity, defined as the volume occupied by a defined amount of hydrated fiber. Water in a food matrix is retained by capillary forces, or by hydrogen bonds to other food molecules. Therefore the food matrix and the physicochemical properties of the fiber will strongly influence water binding. Differences in water binding between different fiber sources are rather influenced by fiber structure and shape but, to a certain extent, also by chemical composition (Lo´pez et al., 1996; Rosell et al., 2009). Fiber with a high amount of pectin-containing primary cell walls and a loose network of polysaccharides has enhanced hydrophilic and elastic properties; this is, for instance, true for sugar beet or citrus fiber. Conversely, fiber with a high number of secondary cell walls rich in crystalline cellulose has poor hygroscopic properties due to their rigid structure (e.g., wheat bran and pea hulls; Auffret et al., 1994). For different types of dried and milled berry pomace, Reissner et al. (2019) showed that water-binding and swelling capacities differ significantly but are at least partially related to the content of soluble dietary fiber (Fig. 1.2). The method of preparation of the fiber also plays an important role. For instance, fiber dried under more severe conditions is known to have a lower water-binding capacity. Akter et al. (2010) showed that the pretreatment of fruit by-products by, for example, washing with hot and cold water increases the hydration properties of processed powders from persimmon peels. Fiber structure and consequently hydration properties may be altered by cooking or autoclaving, extrusion cooking, high hydrostatic pressure, drying, microwave-assisted drying, vacuum drying, and chemical treatˇ ment (e.g., Soronja-Simovi´ c et al., 2016; Talens et al., 2017; Tejada-Ortigoza et al., 2017). Water-binding and swelling capacities of fruit fiber usually decrease with decreasing particle size, mainly because grinding causes the matrix to collapse and reduces the space available for free water. Apart from particle size, grinding also changes the physical structure of the matrix that affects water binding (Auffret et al., 1994). The influence of particle size on water-holding capacity is not that strict since, apart from matrix collapse, other effects may become prominent. Fiber with a high content of microcrystalline cellulose has a higher mechanical resistance so that grinding

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Valorization of Fruit Processing By-products

FIGURE 1.2 Water-binding capacity (g/g, black bars), swelling capacity (mL/g, gray bars), and fat-absorption capacity (g/g, white bars) of five berry pomace varieties dried at 60 C for 24 h, and subsequently milled to x50 , 120 μm. Data redrawn from Reissner, A.-M., AlHamimi, S., Quiles, A., Schmidt, C., Struck, S., Hernando, I., et al., 2019. Composition and physicochemical properties of dried berry pomace. J. Sci. Food Agric. 99, 1284
1293, with permission from Wiley.

leads to an increase in the total pore volume that is accessible to water and, subsequently, to a higher water uptake (Auffret et al., 1994; Lo´pez et al., 1996). For coconut residue fiber the particle size with maximum hydration property was found to be 550 μm; smaller or larger particles reduced hydration (Raghavendra et al., 2004). When selecting fiber for specific applications, the processing history should therefore be considered (Robertson et al., 2000). As regards chemical effects it is mainly the fat content of the fiber and the ionic strength of the solubilization medium that negatively affect water-binding and swelling capacities.

1.4

Application of fruit pomace in baked products

Baked but also extruded foods based on cereals can be considered as the most important target products for pomace utilization. When it comes to including pomace in the formulation, it is clearly necessary to distinguish between sweet and soft cakes, brittle cookies and biscuits, bread and extruded products. The partial substitution of the main ingredients— these are, depending on the commodity, (wheat) flour but also sugar and/or fat—results in changes of the doughs or batters that must be taken into account during subsequent processing, and in modified product properties. There are numerous studies in which fruit pomace has been used to replace the mentioned compounds in soft bakery products (for instance, Mildner-Szkudlarz et al., 2015; Quiles et al., 2018; Struck et al., 2016a). The impact of each of the ingredients on cake batter properties has to be considered when introducing fruit pomace into the system. The fiber significantly hampers the creation of an aerated structure and, because of its high affinity for water, increases the viscosity of the batter. The consequence of these changes is limited volume expansion during baking, resulting in an increased crumb density and in a firmer, more gummy and less cohesive texture of the final products (Foschia et al., 2013). A meta-analysis on sensory consumer acceptance revealed that fiber-enriched cereals foods are usually downgraded, especially when the acceptance of the reference food is high (Grigor et al., 2016). An approach to overcome the problems related to the high water-binding capacity of the fruit fiber was presented by Struck et al. (2016a) who modified the respective formulations so that reference and test batters were isoviscous. With the general objective to increase the fiber content of cakes, dried pomace of different origins was incorporated in formulations, either as an additional compound or by partially replacing flour (e.g., Mildner-Szkudlarz et al., 2015; Romero-Lopez et al., 2011; Rupasinghe et al., 2008; Walker et al., 2014). A comparison of the outcomes of such studies is difficult as study design and experimental methods differ to a large extent. For all this work it is valid to state that the addition of fruit by-products increased the fiber content and the content of the accompanied bioactive compounds, and reduced the energy density of the final products. However, it remains open as to whether these products, despite the observed effects on crumb properties and sensory characteristics, have been finally accepted by the consumer. When intending to partially replace fat with dried fruit by-products, the manifold functionalities of this basic ingredient must be taken into account. Fat helps to incorporate air bubbles in the cake batter and contributes to emulsification during mixing, and it also helps in leavening during baking and in stabilizing crust and crumb (Rodriguez-Garcia et al., 2014a,b; Zahn et al., 2010). The functionalities must also be taken into account if dried fruit by-products are intended to replace part of the sugar in the formulation. The technological functionality of sugar in sweet baked foods has recently been summarized by Struck et al. (2016b). In brief, sugar has a tenderizing effect on crumb texture from restricting gluten network formation and the increase in starch gelatinization and egg protein denaturation temperatures, but also it contributes to crust color formation during baking through caramelization. Sugar furthermore assists in the

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FIGURE 1.3 Group average plots for muffin descriptors obtained by General Procrustes Analysis. Muffin samples in the consensus space are displayed for replicate session 1 (open circles) and 2 (closed circles). For multiple occurrences of descriptors at a similar position in the plot, character size is proportional to the number of assessors who used them. CE, Cellulose; FA, apple fiber; FO, oat fiber; FP, pea fiber; FW, wheat fiber; IF, inulin; MD, maltodextrin; PD, polydextrose; REF, reference; WB, wheat bran. From Zahn, S., Forker, A., Kru¨gel, L., Rohm, H., 2013. Combined use of rebaudioside A and fibers for partial sucrose replacement in muffins. LWT—Food Sci. Technol. 50, 695
701, with permission from Elsevier.

formation of crystalline agglomerations of fat, thus improving air entrapment and air bubble stability during baking, resulting in more porous and spongy products. In addition, it is of strategic importance whether a reduced sweetness as the second main effect should be passed on to the consumer, or is the subject of substitution through artificial or natural high-intensity sweeteners. Using different fibers for partial sugar replacement and steviol glycosides for sweetening purposes, Zahn et al. (2013) demonstrated that the type of the fiber significantly affects the physical properties of the respective cakes, and that fiber properties also determine the sensory characteristics of the products (Fig. 1.3). As regards cookies and biscuits the introduction of fruit pomace in the system influences the mechanical action needed during development of the dough, the behavior during baking, and product properties. The high affinity of dried pomace toward water significantly affects its absorption so that additional water should be added; a relative increase in water absorption of more than 25% was determined in farinograph experiments after partial flour substitution (Ajila et al., 2008; Kohajdova´ et al., 2013). It is mainly the high pectin content of pomace that was considered responsible for these effects. It needs however to be mentioned that an adverse phenomenon, namely reduced water binding through the addition of pomace with a high lignin content, was also observed (Mildner-Szkudlarz et al., 2013). In addition, a delayed dough development caused by fruit pomace, mainly through the prevention of gluten hydration, must be considered (Kohajdova´ et al., 2013; Srivastava et al., 2014), and dough stability is also negatively affected. The fiber hinders the ability of proteins to form a stable gluten network. However, in some cases, an increase in dough stability, which was attributed to enhanced interactions between water, fiber, and gluten, was also reported (Kojahdova et al., 2014). In contrast to soft bakery products baked in molds, which increase their volume through changes in height, spreading is a desired technological property during baking of cookies and biscuits. A reduced spreading results in smaller cookies with higher density, and was observed when more than 10%
15% wheat flour was replaced by dried fruit pomace (Ajila et al., 2008; Kohajdova´ et al., 2013). As a general conclusion from studies dealing with this subject, the main factor influencing spreading during baking is pomace composition. Mildner-Szkudlarz et al. (2013) observed a higher flowability of the dough for grape pomace with a high lignin content. Hardness is one of the most important physical properties of baked cookies and biscuits. Adding more water to the formulation to achieve a kneadable dough may lead to an extensive gluten structure that causes a sufficient hardening of the final products (Ajila et al., 2008; Larrea et al., 2005). Another important aspect is that, in most cases, fruit pomace comes with an individual color and a flavor that is also evident in the products. In their work on savory crackers, Schmidt et al. (2018) used black currant pomace for partial wheat flour substitution. In this case the darker color was

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Valorization of Fruit Processing By-products

associated with chocolate by the consumers which resulted in a decreased acceptance. This was overcome by spreading sesame seeds on top of the biscuits to avoid the underlying dark-sweet bias. Incorporating dietary fiber in bread is generally detrimental to the formation of an aerated structure. It therefore diminishes the appeal of fiber-fortified bread and restricts the benefits that can be obtained through the consumption of fiber (Campbell et al., 2008). Fruit pomace is an alternate fiber source to the frequently used cereal bran. Studies that have applied fruit by-products in bread usually conclude that these can be incorporated at some limited level while maintaining acceptable bread quality. Cooked fruit by-products (apple, pear, and date pomace) in wheat bread formulations exhibited a significant influence on dough and product properties. There was increased water absorption, and dough stability was also affected. Extensibility, softening, breakdown, and setback of the dough as measured in a farinograph usually decrease with fiber addition. The final bread with as low as 2% fiber showed a specific volume comparable to the reference but a more aerated crumb structure (Bchir et al., 2013). A reduction in bread volume was observed after the addition of hazelnut (Anil, 2007) or sugar beet fiber (Filipovic et al., 2007). Sivam et al. (2010) noted that the effects of adding noncereal fiber to wheat bread generally are reduced volume, increased crumb firmness, and darker appearance, and that the negative effects derive mainly from the dilution of gluten and the interactions between fiber, water, and gluten. The way in which fiber in different amounts can be incorporated in wheat dough has recently been addressed by Struck et al. (2018) (Fig. 1.4). O’Shea et al. (2013) incorporated orange pomace in gluten-free bread and found that, as regards water absorption, the fiber competes with starch. This reduces starch granule swelling, and decreases batter viscosity and gelatinization rate. At a level of 5.5 g pomace per 100 g (rice flour 1 potato starch), the orange pomace bread was considered similar in sensory acceptability to the control, with a slightly less pleasant texture observed during chewing. Rocha Parra et al. (2015) incorporated apple pomace in gluten-free bread, noting that high fiber levels gave a less cohesive and resilient crumb and a lower specific volume. Surplus water served to counteract the negative effects of pomace to some extent. Many expanded snacks with a crispy texture are produced by high-temperature short-time extrusion that takes advantage of the structural changes of starch induced by temperature and pressure. Extruded products such as breakfast cereals or savory snacks are based on starch and therefore are low in dietary fiber and protein. Any incorporation of fruit pomace in the respective formulation therefore affects the behavior during processing and the resulting product properties, for example, water absorption and solubility, expansion, texture, and starch digestibility. When starchcontaining raw material—in most cases, corn grit—is partly replaced by fruit pomace (here, replacement levels of up to 50% were evaluated, see Gumul et al., 2011, or White et al., 2010) both compounds compete for water so that starch gelatinization is significantly affected (Ma¨kila¨ et al., 2014). The high water affinity of fruit pomace is also responsible for the increased shear viscosity of the melt which hinders the flashing off of steam at the extruder die and further limits FIGURE 1.4 Scanning electron microscopy images of dough samples with varying amounts of black currant pomace (BCP). (1) Reference; (2) 10% BCP; (3) 20% BCP; (4) 30% BCP. F, Fiber particles from BCP; G, protein network; S, starch granules. From Struck, S., Straube, D., Zahn, S., Rohm, H., 2018. Interaction of wheat macromolecules and berry pomace in model dough: rheology and microstructure. J. Food Eng. 223, 109
115, with permission from Elsevier.

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FIGURE 1.5 Expansion ratio of extrudates with different moisture content (MC) and apple pomace (AP). From Karkle, E.L., Alavi, S., Dogan, H., 2012. Cellular architecture and its relationship with mechanical properties in expanded extrudates containing apple pomace. Food Res. Int. 46, 10
21, with permission from Elsevier.

bubble growth. Fiber particles could physically rupture bubble cell walls, hence leading to an earlier collapse of bubbles and therefore a reduced expansion (Altan et al., 2008). As regards the effects of fruit pomace on the amount of soluble components in extrudates that is linked to molecular degradation during extrusion, reports are controversial. Changes in solubility are presumably caused by a reduced starch damage during extrusion, or by effects of different ratios of soluble to insoluble fiber in the pomace that was used (Altan et al., 2009; Karkle et al., 2012a; Selani et al., 2014). Reduced starch gelatinization in line with a lower gas-holding capacity and also effects related to the geometry of the used fiber have been considered responsible for the decrease in radial expansion and the increase in density of pomace-containing extrudates (Karkle et al., 2012a,b; Fig. 1.5). A less porous structure with smaller gas cells is directly responsible for a less crispy, more fragile texture (Struck et al., 2016b). Published data lead however to the conclusion that the magnitude of the respective effects is largely determined by type and origin of the pomace and, with regards to water solubility, is dependent on the amount of soluble and insoluble fiber (Selani et al., 2014; Karkle et al., 2012a). In addition, some limitations regarding applicability come from effects of the incorporated pomace on the flavor and taste. For example, Gumul et al. (2011) reported an amount of 10% defatted black currant seeds in cornmeal extrudates as acceptable from the sensory point of view, whereas products with a higher amount of pomace were significantly downgraded.

1.5

Pasta

Pasta is a traditional food usually based on refined or whole wheat flour. It is popular worldwide, mainly because of its low cost, ease of production, versatility, sensory attributes, and long shelf life (Ajila et al., 2010). Pasta is produced by mixing and kneading cereal flour or semolina with water; the addition of egg and salt is optional and depends on local production habits. Extrusion processing facilitates mixing and kneading of dough under pressure and friction which enables protein interactions through disulfide, hydrogen, and hydrophobic bonds and therefore the development of a cross-linked gluten matrix. The passage through the die with rotating blades at the end of the extruder barrel gives the pasta its final form (Bustos et al., 2015). The substitution of wheat flour or durum semolina with dietary fiber-rich raw materials such as fruit pomace significantly alters the product characteristics, particularly color, water absorption and swelling during cooking, cooking time and cooking loss, texture and other sensory attributes. Cooking loss describes the amount of solids diffusing from the raw pasta structure (either fresh or dried) into the cooking water. This parameter is used to describe the cooking performance of pasta, and a value of approximately 8% is considered to be the limit for good quality (Bustos et al., 2015). The dietary fiber in fruit processing by-products interferes with the starch/gluten network in pasta dough and causes a higher loss of gelatinized starch and other nonstarch polysaccharides than in control samples. This effect has been observed for mango peel powder (Ajila et al., 2010), orange by-product fiber (Crizel et al., 2015), pomegranate seed powder (Dib et al., 2018), carrot pomace (Gull et al., 2015), and grape marc powder (Sant’Anna et al., 2014) that were used for pasta making. The water affinity of the

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Valorization of Fruit Processing By-products

dietary fiber is responsible for an uneven distribution of water within the pasta matrix and prevents starch swelling, thereby increasing starch leaching from the matrix during cooking (Tudoricaˇ et al., 2002). Analytical measurements of pasta texture can either be performed on dry pasta to determine fracturability, for instance in relation to packaging or transportation issues, but also to assess the quality of cooked pasta; here, noodle firmness and adhesiveness are the most relevant properties. When applying the traditional (but now somewhat challenged) texture profile analysis the sample is compressed in two cycles, with the original aim to simulate chewing. When doing so, the maximum force during the first compression cycle is defined as firmness, and the negative work between the two cycles refers to adhesiveness. Ajila et al. (2010) showed that the addition of 7.5% mango peel powder to a macaroni formulation increased the firmness from 0.44 N (control) to 0.73 N. Insoluble dietary fiber causes a reduction in starch swelling and therefore decreases water absorption of the pasta during cooking, which in turn results in a higher firmness of the cooked pasta (Aravind et al., 2012). Pomegranate seed powder on the other hand decreased the firmness of gluten-free pasta when applied at a level above 5%. This effect was explained by the high waterholding capacity of the pomegranate seed powder (Dib et al., 2018). Sensory evaluation of pasta with grape marc powder showed that a replacement of 2.5% of wheat flour resulted in products with a similar flavor and adequate overall acceptance compared to a control sample. At higher concentrations the grape marc powder pasta was rejected in sensory testing because of an unexpected aftertaste which reduced overall acceptability (Sant’Anna et al., 2014). Similar results were observed for pomegranate seed powder, where an application level also of 2.5% gave results similar to that of a control formulation, but higher levels (10% and 12.5%) resulted in a less accepted pasta (Dib et al., 2018). The addition of orange by-products to a pasta formulation led to the presence of a bitter taste and therefore less overall acceptability. According to Crizel et al. (2015), this negative influence on sensory attributes could be counteracted by a pretreatment of the raw material to reduce the amounts of the compounds responsible for bitterness. In general, the replacement of wheat flour with fruit processing by-products results in an increased polyphenol and dietary fiber content which increases the nutritional value of the final product. The negative effects on cooking loss, texture, and sensory attributes have to be analyzed for each possible fiber-enriched product to find an optimum replacement level.

1.6

Meat products

Oxidation reactions are responsible for several changes that occur during meat processing and the subsequent storage of the product, and which result in off flavors from, for instance, lipid oxidation, and discoloration from meat pigment oxidation. With the application of antioxidants it is possible to prevent these negative changes to a certain extent and to increase the shelf life of the products (Lorenzo et al., 2018). As fruit by-products are rich in phytochemicals and therefore natural antioxidants, they might serve as promising ingredients to inhibit oxidation reactions and the formation of rancid odors (Ahmad et al., 2015). In many cases, the extraction of fruit processing by-products before application in meat products is recommended to gain a high concentration of phytochemicals and to simultaneously exclude interfering compounds such as dietary fiber or protein. The fractionation of fruit pomace can be realized by alcoholic extraction, supercritical carbon dioxide extraction, or high-pressure extraction with ethanol and water (e.g., Garrido et al., 2011; Kryˇzeviˇcu¯ t˙e et al., 2017; Vauchel et al., 2015). The resulting extracts from raspberry pomace were shown to prolong storage time of beef burgers (application level up to 1%) and to exhibit antimicrobial effects without changing the sensory profile of the product (Kryˇzeviˇcu¯ t˙e et al., 2017). Seasonings produced by drying and milling of wine pomace incorporated in refrigerated and frozen beef patties reduced the thiobarbituric acid reactive substances (TBARS) levels during storage and therefore prevented lipid oxidation. In comparison with sulfite, an antioxidant that is widely used in the meat industry, the wine pomace seasoning was more effective in delaying the formation of rancid odors during storage of the products. With the addition of red wine pomace, no TBARS were formed in cooked beef patties; in raw patties, a reduction of 60% compared to a control sample was possible (Garcı´a-Lomillo et al., 2017; Fig. 1.6). Fruit by-products can also be added to animal feed to benefit from the antioxidant effect and to introduce the compounds into the meat. Mango seed extract, prepared by ethanolic extraction, was added to a broiler chicken diet at a level of 400 mg/kg and increased the yellowness of the meat at 60 days of storage and also helped in maintaining breast meat color during frozen storage (Freitas et al., 2015). Chokeberry pomace showed promising results as a dietary supplement for broilers, though the optimal dosage for antioxidant activity requires further investigation (Loetscher et al., 2013). Aqueous extracts of pomegranate and grape by-products added to raw lamb patties resulted in lower microbial counts for mesophilic and psychrotrophic microorganisms after 7 days of refrigerated storage than for control samples.

Fruit processing by-products as food ingredients Chapter | 1

11

FIGURE 1.6 Thiobarbituric acid reactive substance (TBARS) levels in raw and cooked beef patties stored in vacuum packaging for 6 months at 218 C. Points show mean values and bars indicate standard deviations at each sampling point (n 5 3). Greek letters (α,β,γ) show statistical differences between samples at the same storage time. Latin letters (a, b, c) show statistical changes (P-value , .05) during storage. Control: patties without any antioxidant; sulfites: patties with 300 ppm of SO2; and SkRWPS: patties with 2 g/100 g of seasoning obtained skin fraction of red wine pomace. From Garcı´a-Lomillo, J., Gonzalez-SanJose, M.L., Del Pino-Garcı´a, R., Ortega-Heras, M., Mun˜iz-Rodrı´guez, P., 2017. Antioxidant effect of seasonings derived from wine pomace on lipid oxidation in refrigerated and frozen beef patties. LWT—Food Sci. Technol. 77, 85
91, with permission from Elsevier.

The antimicrobial effect was however less pronounced for enterobacteriaceae and lactic acid bacteria. The results even suggested that sodium ascorbate could be replaced by grape pomace extracts as an antioxidant in minced meat (Andre´s et al., 2017). Additionally, Aquilani et al. (2018) reported that sodium nitrite in dry fermented sausages could be replaced by a natural antioxidant consisting of grape seed extract and olive pomace hydroxytyrosol without negative effects on the aroma profile, on instrumental hardness, and on overall acceptability. In sensory analyses, only colorrelated attributes (redness and color uniformity) were evaluated with lower scores. An application level of 2.5% of cranberry pomace extract reduced the bacterial count of pathogens sufficiently without negative effects on organoleptic properties (Stobnicka and Gniewosz, 2018). Apart from the antioxidative effect, fruit pomace can be applied to meat products to enrich the dietary fiber content, or to act as a fat replacer (Yadav et al., 2016; Rather et al., 2015). Apple pomace was incorporated in chicken sausages, resulting in acceptability values at 3% application level that were comparable with a control sample. Higher application levels (6% and 9%) resulted in sausages that were perceived as less juicy than the control, which might be attributed to the high water-binding capacity of the fiber. Instrumental texture analysis showed an increased hardness for sausages with apple pomace (Yadav et al., 2016). Dietary fiber concentrates of pineapple pomace applied to Vienna-type sausages increased antioxidant polyphenol and carotenoid contents and were considered as potential functional ingredients (Montalvo-Gonza´lez et al., 2018). Since consumer demands tend to show a preference for natural products, the meat industry is seeking natural solutions to reduce the negative effects of oxidation and microbial growth that cause changes in color and odor during storage. Fruit by-products are a natural source of antioxidants and can be applied as a powder or as extracts in meat products. They may be considered to be a promising alternative for conventional synthetic antioxidants with a great potential for the meat industry.

12

1.7

Valorization of Fruit Processing By-products

Conclusion

Fruit processing by-products have high potential as food ingredients since they facilitate an increase in the sustainability of the fruit processing chain through reusing a product that is often considered as waste. The fruity flavor and interesting color of pomaces provide opportunities for the development of new foods with high nutritional value, and pomaces might even be considered as natural alternatives to conventional synthetic additives. However, the application in foods is often limited because of specific physicochemical and technofunctional properties. Fruit processing by-products are rich in dietary fiber and therefore frequently exhibit high water-binding and swelling capacities as well as a high oil-binding capacity that significantly affect the characteristics of the respective foods. Their high affinity to water causes variations in the hydration of food macromolecules, and in rheological properties. Therefore each application demands a thorough investigation of the possible integration level to produce foods with satisfying sensory properties. To reach this goal, an adaption of the formulation or the manufacturing process might be necessary. Fruit processing by-products are therefore an interesting opportunity for adding value by upcycling of a waste stream and represent food ingredients with high contents of dietary fiber and phytochemicals.

References Abrahamsson, V., Rodriguez-Meizoso, I., Turner, C., 2015. Supercritical fluid extraction of lipids from linseed with on-line evaporative light scattering detection. Anal. Chim. Acta 853, 320
327. Adetunji, L.R., Adekunle, A., Orsat, V., Raghavan, V., 2017. Advances in the pectin production process using novel extraction techniques: a review. Food Hydrocolloids 62, 239
250. Ahmad, S.R., Gokulakrishnan, P., Giriprasad, R., Yatoo, M.A., 2015. Fruit-based natural antioxidants in meat and meat products: a review. Crit. Rev. Food Sci. Nutr. 55, 1503
1513. Ajila, C.M., Leelavathi, K., Prasada Rao, U.J.S., 2008. Improvement of dietary fiber content and antioxidant properties in soft dough biscuits with the incorporation of mango peel powder. J. Cereal Sci. 48, 319
326. Ajila, C.M., Aalami, M., Leelavathi, K., Rao, U.J.S.P., 2010. Mango peel powder: a potential source of antioxidant and dietary fiber in macaroni preparations. Innov. Food Sci. Emerg. Technol. 11, 219
224. Akter, M.S., Ahmed, M., Eun, J.B., 2010. Dietary fibre components, antioxidant activities and hydration properties of ripe persimmon (Diospyros kaki L. cv. Daebong) peel powders as affected by different washing treatments. Int. J. Food Sci. Technol. 45, 1464
1471. Alba, K., MacNaughtan, W., Laws, A.P., Foster, T.J., Campbell, G.M., Kontogiorgos, V., 2017. Fractionation and characterisation of dietary fibre from blackcurrant pomace. Food Hydrocolloids 81, 398
408. Altan, A., McCarthy, K.L., Maskan, M., 2008. Evaluation of snack foods from barley
tomato pomace blends by extrusion processing. J. Food Eng. 84, 231
242. Altan, A., McCarthy, K.L., Maskan, M., 2009. Effect of extrusion process on antioxidant activity, total phenolics and β-glucan content of extrudates developed from barley-fruit and vegetable by-products. Int. J. Food Sci. Technol. 44, 1263
1271. Andre´s, A.I., Petro´n, M.J., Ada´mez, J.D., Lo´pez, M., Timo´n, M.L., 2017. Food by-products as potential antioxidant and antimicrobial additives in chill stored raw lamb patties. Meat Sci. 129, 62
70. Anil, M., 2007. Using of hazelnut testa as a source of dietary fiber in breadmaking. J. Food Eng. 80, 61
67. Aquilani, C., Sirtori, F., Flores, M., Bozzi, R., Lebret, B., Pugliese, C., 2018. Effect of natural antioxidants from grape seed and chestnut in combination with hydroxytyrosol, as sodium nitrite substitutes in Cinta Senese dry-fermented sausages. Meat Sci. 145, 389
398. Aravind, N., Sissons, M., Egan, N., Fellows, C., 2012. Effect of insoluble dietary fibre addition on technological, sensory, and structural properties of durum wheat spaghetti. Food Chem. 130, 299
309. Auffret, A., Ralet, M.-C., Guillon, F., Barry, J.-L., Thibault, J.-F., 1994. Effect of grinding and experimental conditions on the measurement of hydration properties of dietary fibres. LWT—Food Sci. Technol. 27, 166
172. Basu, A., Du, M., Leyva, M.J., Sanchez, K., Betts, N.M., Wu, M., et al., 2010. Blueberries decrease cardiovascular risk factors in obese men and women with metabolic syndrome. J. Nutr. 140, 1582
1587. Bchir, B., Rabetafika, H.N., Paquot, M., Blecker, C., 2013. Effect of pear, apple and date fibres from cooked fruit by-products on dough performance and bread quality.. Food Bioprocess Technol. 7, 1114
1127. Blackwood, A.D., Salter, J., Dettmar, P.W., Chaplin, M.F., 2000. Dietary fibre, physicochemical properties and their relationship to health. J. R. Soc. Promotion Health 120, 242
247. Bo¨hm, V., Ku¨hnert, S., Rohm, H., Scholze, G., 2006. Improving the nutritional quality of microwave-vacuum dried strawberries: a preliminary study. Food Sci. Technol. Int. 12, 67
75. Brennan, C.S., 2005. Dietary fibre, glycaemic response, and diabetes. Mol. Nutr. Food Res. 49, 560
570. Bustos, M.C., Perez, G.T., Leon, A.E., 2015. Structure and quality of pasta enriched with functional ingredients. RSC Adv. 5, 30780
30792. Campbell, G.M., Ross, M., Motoi, L., 2008. Expansion capacity of bran-enriched doughs in different scales of laboratory mixers. In: Campbell, G.M., Scanlon, M.G., Pyle, D.L. (Eds.), Bubbles in Foods 2. Eagan Press, St. Paul, MN, pp. 323
336. Chu, Y.-F., Liu, R.H., 2005. Cranberries inhibit LDL oxidation and induce LDL receptor expression in hepatocytes. Life Sci. 77, 1892
1901.

Fruit processing by-products as food ingredients Chapter | 1

13

Crizel, T.M., Rios, A.O., Thys, R.C.S., Floˆres, S.H., 2015. Effects of orange by-product fiber incorporation on the functional and technological properties of pasta. Food Sci. Technol. (Campinas) 35, 546
551. Dib, A., Kasprzak, K., Wo´jtowicz, A., Benatallah, L., Waksmundzka-Hajnos, M., Zidoune, M.N., et al., 2018. The effect of pomegranate seed powder addition on radical scavenging activity determined by TLC
DPPH test and selected properties of gluten-free pasta. J. Liquid Chromatogr. Related Technol. 41, 364
372. EFSA Panel on Dietetic Products, Nutrition, and Allergies, 2010. Scientific opinion on dietary reference values for carbohydrates and dietary fibre. EFSA J. 8, 1462. Eim, V.S., Simal, S., Rossello´, C., Femenia, A., 2008. Effects of addition of carrot dietary fibre on the ripening process of a dry fermented sausage (sobrassada). Meat Sci. 80, 173
182. Figuerola, F., Hurtado, M.L., Este´vez, A.M., Chiffelle, I., Asenjo, F., 2005. Fibre concentrates from apple pomace and citrus peel as potential fibre sources for food enrichment. Food Chem. 91, 395
401. Filipovic, N., Djuric, M., Gyura, J., 2007. The effect of the type and quantity of sugar-beet fibers on bread characteristics. J. Food Eng. 78, 1047
1053. Foschia, M., Peressini, D., Sensidoni, A., Brennan, C.S., 2013. The effects of dietary fibre addition on the quality of common cereal products. J. Cereal Sci. 58, 216
227. ˆ .S., Pereira, A.L.F., Abreu, V.K.G., Trevisan, M.T.S., et al., 2015. Effect of dietary ethanol extracts of mango (Mangifera indiFreitas, E.R., Borges, A ca L.) on lipid oxidation and the color of chicken meat during frozen storage. Poultr. Sci. 94, 2989
2995. Garau, M.C., Simal, S., Rossello´, C., Femenia, A., 2007. Effect of air-drying temperature on physico-chemical properties of dietary fibre and antioxidant capacity of orange (Citrus aurantium v. Canoneta) by-products. Food Chem. 104, 1014
1024. Garcı´a-Lomillo, J., Gonzalez-SanJose, M.L., Del Pino-Garcı´a, R., Ortega-Heras, M., Mun˜iz-Rodrı´guez, P., 2017. Antioxidant effect of seasonings derived from wine pomace on lipid oxidation in refrigerated and frozen beef patties. LWT—Food Sci. Technol. 77, 85
91. Garrido, M.D., Auqui, M., Martı´, N., Linares, M.B., 2011. Effect of two different red grape pomace extracts obtained under different extraction systems on meat quality of pork burgers. LWT—Food Sci. Technol. 44, 2238
2243. Grassino, A.N., Barba, F.J., Brncic, M., Lorenzo, J.M., Lucini, L., Brncic, S.R., 2018. Analytical tools used for the identification and quantification of pectin extracted from plant food matrices, wastes and by-products: a review. Food Chem. 266, 47
55. Grigelmo-Miguel, N., Martı´n-Belloso, O., 1999. Comparison of dietary fibre from by-products of processing fruits and greens and from cereals. LWT—Food Sci. Technol. 32, 503
508. Grigor, J.M., Brennan, C.S., Hutchings, S.C., Rowlands, D.S., 2016. The sensory acceptance of fibre enriched cereal foods: a meta-analysis. Int. J. Food Sci. Technol. 51, 3
13. Gull, A., Prasad, K., Kumar, P., 2015. Effect of millet flours and carrot pomace on cooking qualities, color and texture of developed pasta. LWT— Food Sci. Technol. 63, 470
474. Gumul, D., Ziobro, R., Zieba, T., Roj, E., 2011. The influence of addition of defatted blackcurrant seeds on pro-health constituents and texture of cereal extrudates. J. Food Qual. 34, 395
402. Helbig, D., Bo¨hm, V., Wagner, A., Schubert, R., Jahreis, G., 2008. Berry seed press residues and their valuable ingredients with special regard to black currant seed press residues. Food Chem. 111, 1043
1049. Hilz, H., Bakx, E.J., Schols, H.A., Voragen, A.G.J., 2005. Cell wall polysaccharides in black currants and bilberries
characterisation in berries, juice, and press cake. Carbohydr. Polym. 59, 477
488. Holtung, L., Grimmer, S., Aaby, K., 2011. Effect of processing of black currant press-residue on polyphenol composition and cell proliferation. J. Agric. Food Chem. 59, 3632
3640. Horszwald, A., Julien, H., Andlauer, W., 2013. Characterisation of Aronia powders obtained by different drying processes. Food Chem. 141, 2858
2863. Iora, S.R.F., Maciel, G.M., Zielinski, A.A.F., da Silva, M.V., Pontes, P.V., de, A., et al., 2015. Evaluation of the bioactive compounds and the antioxidant capacity of grape pomace. Int. J. Food Sci. Technol. 50, 62
69. Karkle, E.L., Alavi, S., Dogan, H., 2012a. Cellular architecture and its relationship with mechanical properties in expanded extrudates containing apple pomace. Food Res. Int. 46, 10
21. Karkle, E.L., Keller, L., Dogan, H., Alavi, S., 2012b. Matrix transformation in fiber-added extruded products: impact of different hydration regimens on texture, microstructure and digestibility. J. Food Eng. 108, 171
182. Khanal, R.C., Howard, L.R., Brownmiller, C.R., Prior, R.L., 2009. Influence of extrusion processing on procyanidin composition and total anthocyanin contents of blueberry pomace. J. Food Sci. 74, H52
H58. Khanal, R.C., Howard, L.R., Prior, R.L., 2010. Effect of heating on the stability of grape and blueberry pomace procyanidins and total anthocyanins. Food Res. Int. 43, 1464
1469. Kohajdova´, Z., Karoviˇcova´, J., Jurasova´, M., 2013. Influence of grapefruit dietary fibre rich powder on the rheological characteristics of wheat flour dough and on biscuit quality. Acta Alimentaria 42, 91
101. Kohajdova´, Z., Karoviˇcova´, J., Magala, M., Kuchtova´, V., 2014. Effect of apple pomace powder addition on farinographic properties of wheat dough and biscuits quality. Chem. Papers 68, 1059
1065. Koponen, J.M., Happonen, A.M., Auriola, S., Kontkanen, H., Buchert, J., Poutanen, K.S., et al., 2008. Characterization and fate of black currant and bilberry flavonols in enzyme-aided processing. J. Agric. Food Chem. 56, 3136
3144. Kosmala, M., Kołodziejczyk, K., Markowski, J., Mieszczakowska, M., Ginies, C., Renard, C.M.G.C., 2010. Co-products of black-currant and apple juice production: hydration properties and polysaccharide composition. LWT—Food Sci. Technol. 43, 173
180.

14

Valorization of Fruit Processing By-products

Koutsos, A., Tuohy, K., Lovegrove, J., 2015. Apples and cardiovascular health—is the gut microbiota a core consideration? Nutrients 7, 3959
3998. Kryˇzeviˇcu¯ t˙e, N., Jaime, I., Diez, A.M., Rovira, J., Venskutonis, P.R., 2017. Effect of raspberry pomace extracts isolated by high pressure extraction on the quality and shelf-life of beef burgers. Int. J. Food Sci. Technol. 52, 1852
1861. Lai, W.T., Khong, N.M.H., Lim, S.S., Hee, Y.Y., Sim, B.I., Lau, K.Y., et al., 2017. A review: modified agricultural by-products for the development and fortification of food products and nutraceuticals. Trends Food Sci. Technol. 59, 148
160. Laroze, L.E., Dı´az-Reinoso, B., Moure, A., Zu´n˜iga, M.E., Domı´nguez, H., 2010. Extraction of antioxidants from several berries pressing wastes using conventional and supercritical solvents. Eur. Food Res. Technol. 231, 669
677. Larrea, M.A., Chang, Y.K., Martı´nez Bustos, F., 2005. Effect of some operational extrusion parameters on the constituents of orange pulp. Food Chem. 89, 301
308. Lattimer, J.M., Haub, M.D., 2010. Effects of dietary fiber and its components on metabolic health. Nutrients 2, 1266
1289. Lee, J., Wrolstad, R.E., 2006. Extraction of anthocyanins and polyphenolics from blueberry processing waste. J. Food Sci. 69, 564
573. Loetscher, Y., Kreuzer, M., Messikommer, R.E., 2013. Oxidative stability of the meat of broilers supplemented with rosemary leaves, rosehip fruits, chokeberry pomace, and entire nettle, and effects on performance and meat quality. Poultr. Sci. 92, 2938
2948. Lo´pez, G., Ros, G., Rinco´n, F., Periago, M.J., Martı´nez, M.C., Ortun˜o, J., 1996. Relationship between physical and hydration properties of soluble and insoluble fiber of artichoke. J. Agric. Food Chem. 44, 2773
2778. Lorenzo, J.M., Pateiro, M., Domı´nguez, R., Barba, F.J., Putnik, P., Kovaˇcevi´c, D.B., et al., 2018. Berries extracts as natural antioxidants in meat products: a review. Food Res. Int. 106, 1095
1104. Ma¨kila¨, L., Laaksonen, O., Diaz, J.M.R., Vahvaselka¨, M., Myllyma¨ki, O., Lehtoma¨ki, I., et al., 2014. Exploiting blackcurrant juice press residue in extruded snacks. LWT—Food Sci. Technol. 57, 618
627. Martin-Cabrejas, M.A., Esteban, R.M., Lopez-Andreu, F.J., Waldron, K., Selvendran, R.R., 1995. Dietary fiber content of pear and kiwi pomaces. J. Agric. Food Chem. 43, 662
666. Matias, M.F.O., de Oliveira, E.L., Gertrudes, E., Magalha˜es, M.M.D.A., 2005. Use of fibres obtained from the cashew (Anacardium ocidentale, L) and guava (Psidium guayava) fruits for enrichment of food products. Braz. Arch. Biol. Technol. 48, 143
150. Mayer-Miebach, E., Adamiuk, M., Behsnilian, D., 2012. Stability of chokeberry bioactive polyphenols during juice processing and stabilization of a polyphenol-rich material from the by-product. Agriculture 2, 244
258. Mazzoni, L., Perez-Lopez, P., Giampieri, F., Alvarez-Suarez, J., Gasparrini, M., Forbes-Hernandez, T.Y., et al., 2016. The genetic aspects of berries: from field to health. J. Sci. Food Agric. 96, 365
371. McKee, L.H., Latner, T.A., 2000. Underutilized sources of dietary fiber: a review. Plant Foods Hum. Nutr. 55, 285
304. Milala, J., Kosmala, M., So´jka, M., Kołodziejczyk, K., Zbrze´zniak, M., Markowski, J., 2013. Plum pomaces as a potential source of dietary fibre: composition and antioxidant properties. J. Food Sci. Technol. 50, 1012
1017. Mildner-Szkudlarz, S., Bajerska, J., Zawirska-Wojtasiak, R., Go´recka, D., 2013. White grape pomace as a source of dietary fibre and polyphenols and its effect on physical and nutraceutical characteristics of wheat biscuits. J. Sci. Food Agric. 93, 389
395. Mildner-Szkudlarz, S., Siger, A., Szwengiel, A., Bajerska, J., 2015. Natural compounds from grape by-products enhance nutritive value and reduce formation of CML in model muffins. Food Chem. 172, 78
85. Minekus, M., Alminger, M., Alvito, P., Ballance, S., Bohn, T., Bourlieu, C., et al., 2014. A standardised static in vitro digestion method suitable for food—an international consensus. Food Funct. 5, 1113
1124. Montalvo-Gonza´lez, E., Aguilar-Herna´ndez, G., Herna´ndez-Ca´zares, A.S., Ruiz-Lo´pez, I.I., Pe´rez-Silva, A., Herna´ndez-Torres, J., et al., 2018. Production, chemical, physical and technological properties of antioxidant dietary fiber from pineapple pomace and effect as ingredient in sausages. CyTA—J. Food 16, 831
839. Nyman, E.M., 2003. Importance of processing for physico-chemical and physiological properties of dietary fibre. Proc. Nutr. Soc. 62, 187
192. O’Shea, N., Doran, L., Auty, M., Arendt, E., Gallagher, E., 2013. The rheology, microstructure and sensory characteristics of a gluten-free bread formulation enhanced with orange pomace. Food Funct. 4, 1856
1863. Otoni, C.G., Avena-Bustillos, R.J., Azeredo, H.M.C., Lorevice, M.V., Moura, M.R., Mattoso, L.H.C., et al., 2017. Recent advances on edible films based on fruits and vegetables—a review. Comprehens. Rev. Food Sci. Food Saf. 16, 1151
1169. Quiles, A., Campbell, G.M., Struck, S., Rohm, H., Hernando, I., 2017. Fiber from fruit pomace: a review of applications in cereal-based products. Food Rev. Int. 34, 162
181. Quiles, A., Llorca, E., Schmidt, C., Reissner, A.-M., Struck, S., Rohm, H., 2018. Use of berry pomace to replace flour, fat or sugar in cakes. Int. J. Food Sci. Technol. 53, 1579
1587. Raghavendra, S.N., Rastogi, N.K., Raghavarao, K.S.M.S., Tharanathan, R.N., 2004. Dietary fiber from coconut residue: effects of different treatments and particle size on the hydration properties. Eur. Food Res. Technol. 218, 563
567. Rather, S.A., Akhter, R., Masoodi, F.A., Gani, A., Wani, S.M., 2015. Utilization of apple pomace powder as a fat replacer in goshtaba: a traditional meat product of Jammu and Kashmir, India. J. Food Meas. Charact. 9, 389. Reissner, A.M., Al-Hamimi, S., Quiles, A., Schmidt, C., Struck, S., Hernando, I., et al., 2019. Composition and physicochemical properties of dried berry pomace. J. Sci. Food Agric. 99, 1284
1293. Renu, B., Agarwal, M., Singh, K., 2017. Heavy metal removal from wastewater using various adsorbents: a review. J. Water Reuse Desal. 7, 387
419. Reque, P.M., Steffens, R.S., Silva, A.M.D., Jablonski, A., Flores, S.H., Rios, A.D., et al., 2014. Characterization of blueberry fruits (Vaccinium spp.) and derived products. Food Sci. Technol. (Campinas) 34, 773
779.

Fruit processing by-products as food ingredients Chapter | 1

15

Robertson, J.A., de Monredon, F.D., Dysseler, P., Guillon, F., Amado, R., Thibault, J.-F., 2000. Hydration properties of dietary fibre and resistant starch: a European collaborative study. LWT—Food Sci. Technol. 33, 72
79. Rocha Parra, A.F., Ribotta, P.D., Ferrero, C., 2015. Apple pomace in gluten-free formulations: effect on rheology and product quality. Int. J. Food Sci. Technol. 50, 682
690. Rodrı´guez-Garcı´a, J., Sahi, S., Hernando, I., 2014a. Functionality of lipase and emulsifiers in low-fat cakes with inulin. LWT—Food Sci. Technol. 58, 173
182. Rodrı´guez-Garcı´a, J., Salvador, A., Hernando, I., 2014b. Replacing fat and sugar with inulin in cakes: bubble size distribution, physical and sensory properties.. Food Bioprocess Technol. 7, 964
974. Rodriguez-Mateos, A., Rendeiro, C., Bergillos-Meca, T., Tabatabaee, S., George, T., Spencer, J.P., 2013. Intake and time dependence of blueberry flavonoid-induced improvements in vascular function: a randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity. Am. J. Clin. Nutr. 98, 1179
1191. Rohm, H., Brennan, C., Turner, C., Gu¨nther, E., Campbell, G., Hernando, I., et al., 2015. Adding value to fruit processing waste: innovative ways to incorporate fibers from berry pomace in baked and extruded cereal-based foods—A SUSFOOD Project. Foods 4, 690
697. Romero-Lopez, M.R., Osorio-Diaz, P., Bello-Perez, L.A., Tovar, J., Bernardino-Nicanor, A., 2011. Fiber concentrate from orange (Citrus sinensis L.) bagase: characterization and application as bakery product ingredient. Int. J. Mol. Sci. 12, 2174
2186. Rosell, C.M., Santos, E., Collar, C., 2009. Physico-chemical properties of commercial fibres from different sources: a comparative approach. Food Res. Int. 42, 176
184. Rupasinghe, H.P.V., Wang, L., Huber, G.M., Pitts, N.L., 2008. Effect of baking on dietary fibre and phenolics of muffins incorporated with apple skin powder. Food Chem. 107, 1217
1224. Sant’Anna, V., Christiano, F.D.P., Marczak, L.D.F., Tessaro, I.C., Thys, R.C.S., 2014. The effect of the incorporation of grape marc powder in fettuccini pasta properties. LWT—Food Sci. Technol. 58, 497
501. Schieber, A., 2017. Side streams of plant food processing as a source of valuable compounds: selected examples. Annu. Rev. Food Sci. Technol. 8, 97
112. Schmidt, C., Geweke, I., Struck, S., Zahn, S., Rohm, H., 2018. Blackcurrant pomace from juice processing as partial flour substitute in savoury crackers: dough characteristics and product properties. Int. J. Food Sci. Technol. 53, 237
245. Schneeman, B.O., 2001. Dietary fibre and gastrointestinal function. In: McCleary, B.V., Prosky, L. (Eds.), Advanced Dietary Fibre Technology. Blackwell Science, Oxford/Malden, pp. 168
176. Selani, M.M., Brazaca, S.G.C., dos Santos Dias, C.T., Ratnayake, W.S., Flores, R.A., Bianchini, A., 2014. Characterisation and potential application of pineapple pomace in an extruded product for fibre enhancement. Food Chem. 163, 23
30. Sharma, S.K., Bansal, S., Mangal, M., Dixit, A.K., Gupta, R.K., Mangal, A.K., 2016. Utilization of food processing by-products as dietary, functional, and novel fiber: a review. Crit. Rev. Food Sci. Nutr. 56, 1647
1661. Sivam, A.S., Sun-Waterhouse, D., Quek, S., Perera, C.O., 2010. Properties of bread dough with added fiber polysaccharides and phenolic antioxidants: a review. J. Food Sci. 75, R163
R174. Skrede, G., Wrolstad, R.E., Durst, R.W., 2000. Changes in anthocyanins and polyphenolics during juice processing of highbush blueberries (Vaccinium corymbosum L.). J. Food Sci. 65, 357
364. Slavin, J., 2013. Fiber and prebiotics: mechanisms and health benefits. Nutrients 5, 1417
1435. Sojka, M., Krol, B., 2008. Composition of industrial seedless black currant pomace. Eur. Food Res. Technol. 228, 597
605. Sojka, M., Klimczak, E., Macierzynski, J., Kołodziejczyk, K., 2013. Nutrient and polyphenolic composition of industrial strawberry press cake. Eur. Food Res. Technol. 237, 995
1007. ˇ ˇ s, Z., Maravi´c, N., Djordjevi´c, M., Djordjevi´c, M., Lukovi´c, J., et al., 2016. Enhancement of physicochemical properties of Soronja-Simovi´ c, D., Sereˇ sugar beet fibres affected by chemical modification and vacuum drying. Food Bioprod. Process. 100, 432
439. Srivastava, P., Indrani, D., Singh, R.P., 2014. Effect of dried pomegranate (Punica granatum) peel powder (DPPP) on textural, organoleptic and nutritional characteristics of biscuits. Int. J. Food Sci. Nutr. 65, 827
833. Stobnicka, A., Gniewosz, M., 2018. Antimicrobial protection of minced pork meat with the use of swamp cranberry (Vaccinium oxycoccos L.) fruit and pomace extracts. J. Food Sci. Technol. 55, 62
71. Struck, S., Plaza, M., Turner, C., Rohm, H., 2016a. Berry pomace: a review of processing and chemical analysis of its polyphenols. Int. J. Food Sci. Technol. 51, 1305
1318. Struck, S., Gundel, L., Zahn, S., Rohm, H., 2016b. Fiber enriched reduced sugar muffins made from iso-viscous batters. LWT—Food Sci. Technol. 65, 32
38. Struck, S., Jaros, D., Brennan, C.S., Rohm, H., 2016c. Sugar replacement in sweetened bakery goods. Int. J. Food Sci. Technol. 49, 1963
1976. Struck, S., Straube, D., Zahn, S., Rohm, H., 2018. Interaction of wheat macromolecules and berry pomace in model dough: rheology and microstructure. J. Food Eng. 223, 109
115. Sudha, M.L., 2011. Apple pomace (by-product of fruit juice industry) as a flour fortification strategy. In: Preedy, V.R., Watson, R.R., Patel, V.B. (Eds.), Flour and Breads and Their Fortification in Health and Disease Prevention.. Elsevier, Amsterdam, pp. 395
405. Talens, C., Arboleya, J.C., Castro-Giraldez, M., Fito, P.J., 2017. Effect of microwave power coupled with hot air drying on process efficiency and physico-chemical properties of a new dietary fibre ingredient obtained from orange peel. LWT—Food Sci. Technol. 77, 110
118. Teixeira, A., Baenas, N., Dominguez-Perles, R., Barros, A., Rosa, E., Moreno, D.A., et al., 2014. Natural bioactive compounds from winery byproducts as health promoters: a review. Int. J. Mol. Sci. 15, 15638
15678.

16

Valorization of Fruit Processing By-products

Tejada-Ortigoza, V., Garcı´a-Amezquita, L.E., Serna-Saldı´var, S.O., Welti-Chanes, J., 2017. The dietary fiber profile of fruit peels and functionality modifications induced by high hydrostatic pressure treatments. Food Sci. Technol. Int. 23, 396
402. Tudoricaˇ, C.M., Kuri, V., Brennan, C.S., 2002. Nutritional and physicochemical characteristics of dietary fiber enriched pasta. J. Agric. Food Chem. 50, 347
356. Vauchel, P., Galvan D’Alessandro, L., Dhulster, P., Nikov, I., Dimitrov, K., 2015. Pilot scale demonstration of integrated extraction
adsorption eco-process for selective recovery of antioxidants from berries wastes. J. Food Eng. 158, 1
7. Vendrame, S., Guglielmetti, S., Riso, P., Arioli, S., Klimis-Zacas, D., Porrini, M., 2011. Six-week consumption of a wild blueberry powder drink increases bifidobacteria in the human gut. J. Agric. Food Chem. 59, 12815
12820. Viebke, C., Al-Assaf, S., Phillips, G.O., 2014. Food hydrocolloids and health claims. Bioact. Carbohydr. Diet. Fibre 4, 101
114. ´ lvarez, J.A., 2010. Role of fiber in cardiovascuViuda-Martos, M., Lo´pez-Marcos, M.C., Ferna´ndez-Lo´pez, J., Sendra, E., Lo´pez-Vargas, J.H., Pe´rez-A lar diseases: a review. Comprehens. Rev. Food Sci. Food Saf. 9, 240
258. Walker, R., Tseng, A., Cavender, G., Ross, A., Zhao, Y., 2014. Physicochemical, nutritional, and sensory qualities of wine grape pomace fortified baked goods. J. Food Sci. 79, S1811
S1822. Wang, L., Xu, H., Yuan, F., Pan, Q., Fan, R., Gao, Y., 2015. Physicochemical characterization of five types of citrus dietary fibers.. Biocatal. Agric. Biotechnol. 4, 250
258. Wawer, I., Wolniak, M., Paradowska, K., 2006. Solid state NMR study of dietary fiber powders from aronia, bilberry, black currant and apple. Solid State Nucl. Magnet. Reson. 30, 106
113. White, B.L., Howard, L.R., Prior, R.L., 2010. Polyphenolic composition and antioxidant capacity of extruded cranberry pomace. J. Agric. Food Chem. 58, 4037
4042. White, B.L., Howard, L.R., Prior, R.L., 2011. Impact of different stages of juice processing on the anthocyanin, flavonol, and procyanidin contents of cranberries. J. Agric. Food Chem. 59, 4692
4698. Yadav, S., Malik, A., Pathera, A., Islam, R.U., Sharma, D., 2016. Development of dietary fibre enriched chicken sausages by incorporating corn bran, dried apple pomace and dried tomato pomace. Nutr. Food Sci. 46, 16
29. Zahn, S., Forker, A., Kru¨gel, L., Rohm, H., 2013. Combined use of rebaudioside A and fibres for partial sucrose replacement in muffins. LWT—Food Sci. Technol. 50, 695
701. Zahn, S., Pepke, F., Rohm, H., 2010. Effect of inulin as a fat replacer on texture and sensory properties of muffins. Int. J. Food Sci. Technol. 45, 2531
2537. Zielinska, M., Michalska, A., 2018. The influence of convective, microwave vacuum and microwave-assisted drying on blueberry pomace physicochemical properties. Int. J. Food Eng. 14, 20170332.

Chapter 2

Apple ˇ Senka Vidovic, ´ Aleksandra Tepic´ Horecki, Jelena Vladic, ´ Zdravko Sumi c, ´ Aleksandra Gavaric´ and Anita Vakula Faculty of Technology Novi Sad, University of Novi Sad, Novi Sad, Serbia

Chapter Outline 2.1 Apple 2.2 Apple fruit processing 2.2.1 Apple fruit juice production 2.2.2 Concentrated fruit juice production 2.2.3 By-products of apple fruit juice production 2.2.4 Other apple processing—apple-containing fruit filter tea production and by-product remaining

2.1

17 18 18 25 26 27

2.3 Possibilities of application of apple processing by-products 2.3.1 Pectin 2.3.2 Valorization of apple by-products through antioxidants extraction 2.4 Conclusion References Further reading

28 29 32 37 37 42

Apple

Apple is one of the most produced, consumed, and most popular fruits worldwide. The global production of apples in 2011 reached 76 million tons (FAOSTAT Production Database, 2013), while approximately 70 million tons of apples are produced worldwide per year (O’Shea et al., 2015; Massias et al., 2015). According to FAO China has taken the predominant position in the world apple industry (Wang et al., 2016; FAOSTAT Production Database, 2016). Until 2013 in China the annual production of fresh apple fruits was approximately 39.7 million tons and the cultivated area was 2.41 million hectares, representing 49% and 46%, respectively, of the world apple production and planting area in that year. In the same year the European Union (EU) and the United States were the second and third largest world producers, respectively (Wang et al., 2016; FAOSTAT Production Database, 2016). In 2017/2018 the United States was ranked third on the list of global leading apple producing countries, with an apple production of approximately 4.65 million metric tons (www.statista.com). Apples are among the major sources of phytochemicals and antioxidants in the human diet. The chemical composition of apples can vary, depending on cultivar, production region, and horticultural practices (Roth et al., 2007). In comparison to other fruit, apples contain insignificant amounts of proteins and lipids, however they are a good source of soluble fiber, especially pectin. Sugar and organic acid contents in apple are highly cultivar dependent (MikulicPetkovsek et al., 2007; Vieira et al., 2009). Their content and especially their ratio greatly affect the consumers’ acceptance and their suitability for processing. The high sugar/acid (S/A) ratio is desired both for processing and direct consumption. Considering the phenolic compounds present in apple, the five major polyphenolic groups are found in different varieties: hydroxycinnamic acids, flavan-3-ols/procyanidins, anthocyanins, flavonols, and dihydrochalcones (Pe´rez-Ilzarbe et al., 1991; Mazza and Velioglu, 1992; Schieber et al., 2001). According to several authors, among phenolic acids the most abundant are p-coumaric, chlorogenic, and feruloylquinic acid; among flavonoids the most abundant are quercetin, catechin, rutin, isorhamnetin, phloridzin, etc.; among procyanidins the most abundant are procyanidin dimer A2, procyanidintrimer C, and phloretin; and among anthocyanins is cyaniding-3-O-galactoside (Go´rna´s et al., 2014). Phloridzin and phloretin 20 -xyloglucoside were the two major dihydrochalcones reported in apple (Oleszek et al., 1988; Pe´rez-Ilzarbe et al., 1991; Spanos and Wrolstad, 1992; McRae et al., 1990). Regarding chemical composition, as several studies have shown, apples have many health benefits, among which the most important are a reduction in the risk of cardiovascular diseases and cholesterol levels (Boyer and Liu, 2004). Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00002-2 © 2020 Elsevier Inc. All rights reserved.

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Valorization of Fruit Processing By-products

2.2

Apple fruit processing

Apples are processed into a variety of products such as apple juice, apple cider, vinegar, jam, apple sauce, fresh apple slices, dry, and canned apple. According to the data of the US Apple Association, in the United States in 2015 68.5% of the total of the apples produced was used as fresh, 2.3% as frozen, 1.8% dried, 10.8% as total canned, while 12.7% was used for fruit juice production (www.us.apple.org). The highest share of apple production, excluding the fresh used apples, is used for the production of apple fruit juice and concentrated apple fruit juice. Generally, apples represent the dominant fruit in fruit juice production. It is partly because apples are one of the most widespread fruit species, and partly because of the balanced ratio of sugar and acid, which makes this fruit very suitable for the production of juices. The production of fruit juices is a very strong and worldwide industry. Statistical data, according to the information from portal www.statista.com, on the total production volume of apple fruit juice in the EU from 2008 to 2017, are showing mainly an increase in production with some fluctuations. According to the same source in 2017, the countries of the EU produced roughly 2.05 billion liters of apple juice (www.statista.com). According to the market size analysis report, the global fruit and vegetable juices market size was valued at US$154.18 billion in 2016 and is expected to grow at a compound annual growth rate of 5.93% during the forecast period. A rise in consumption of these products, changes in consumer tastes, adoption of healthier diet, and advent of cold-pressed juices are the major factors accelerating the growth of this market globally (www.grandviewresearch.com). Some apple products, such as dry and canned apples, or by-products of apple processing, such as apple pomace generated during apple juice production, are used as one of the dominant compounds in the production of other food products, such as fruit tea and fruit filter tea. In the production of fruit filter tea apples are usually used as dried, after being crushed and milled, but if the fruit tea is not in the form of a filter bag than canned apples can also be used. As data are showing, an increased demand for apples and their application in this food industry sector in the forecast period should be expected in the EU generally. Namely, according to data of Centre for the Promotion of Imports from developing countries (www.cbi.eu) in all European markets, green teas and herbal/fruit teas are becoming increasingly popular among consumers. This increasing popularity is the result of a growing consumer awareness of the health benefits of these teas. Today herbal/fruit tea is used as a beverage and as a source of health-beneficial compounds. Many therapeutic properties such as neuroprotective, cardioprotective, chemoprotective, anticarcinogenic, hepatoprotective, and antiinflammatory properties have been attributed to this kind of herbal/fruit preparations (Vidovi´c et al., 2013; Campanella et al., 2003; Visioli et al., 2000). In Serbia, as an example, the production of teas and other herbal products have been increased at a rate of 10% annually (Vidovi´c et al., 2013).

2.2.1

Apple fruit juice production

As it has been mentioned above, one of the highest shares of apple production is used for the production of apple fruit juice. Therefore it can be concluded that apple fruit juice is the dominant food product obtained from apple fruit processing. There are many different types of fruit juices. They can basically differ in terms of raw materials, structure, quality, fruit content, and packaging methods. According to the content of insoluble ingredients (suspensoids) of fruit, fruit juices can be classified into the subcategories of clear, opalescent, cloudy (turbid) juice, and pulp-enriched (Rajauria and Tiwari, 2017). In Fig. 2.1 all phases in the production of clear apple fruit juice are presented. Fruit juices are produced mainly by the mechanical processing of fruit, which is not fermented, but is capable of fermentation. Fruit juices must have adequate color, as well as the taste and aroma of original fruit, and they are not allowed to contain additives and synthetic flavorings. The preservation of fruit juices is achieved by thermal treatment, that is, pasteurization. As an acidic and juicy fruit with high sugar content and recognizable flavor, apples are suitable for the production of juices and they present one of the most important raw materials for fruit juice production. Apples are suitable for the production of juice since apple juice has a pleasant taste and contains water-soluble coloring matter which enables the production of intense colored juice even after clarification and filtering. Besides, they comprise a fruit that gives a high percentage of juice, which is important because profitable production could be achieved only with a raw material that gives a high percentage of juice. According to all these parameters, apples represent a fruit that is convenient for the production of predominantly clear fruit juice and concentrated fruit juice (Niketi´c-Aleksi´c, 1988; Rajauria and Tiwari, 2017).

2.2.1.1 Quality raw material—first step of successful apple fruit juice production The selection of the optimal variety, adequate agricultural production, well organized harvesting, and fruit transportation are the first steps that enable the production of quality apple juice. When choosing an apple variety intended for

Apple Chapter | 2

FIGURE 2.1 Layout of concentrated clear apple juice production.

Apple

Water, for transport

Buffer tank

Water, for washing

Washing

19

Wastewater

Sorting

Milling

Enzymes

Water, for extraction

Enzymatic treatment

Pressing

Pomace Aroma

Preconcentration Water vapor Enzymes, auxiliary clarification agents

Clarification

Turbid layer

Auxiliary filtering agents

Auxiliary filtering agents

Clear layer

Filtration vacuum filter

Filtration Kieselghur filter

Concentration vacuum evaporator

Auxiliary filtering agents

Water vapor

Filtration Kieselguhr filter

Filtration frame-plate filter

Concentration vacuum evaporator

Water vapor

Storage

Pasteurization

Packaging material

Aseptic filling

Storage

the production of apple juice, it is important to take into account that these varieties need to have a good yield of a separate liquid part, to give the high percentage of juice. Besides, the apple varieties should be selected to give the fruit of adequate taste, color, sugar content, and acidity. Generally, when choosing the raw material for fruit juice processing, beside the selection of the variety, it is very important to choose the fruit that is ripe and healthy enough. The level of ripeness directly affects the content of dry matter, aromatic, and other compounds in the fruit, and these impact the sensory properties as well as the amount of obtained juice. Only optimally ripe fruits have the ideal S/A ratio and also the most valuable components responsible

20

Valorization of Fruit Processing By-products

for taste and smell. Insufficiently ripe, especially green, fruits have less sugar and more starch, which results in less juice and poor quality. On the other hand, overripe fruit could lose the acidic components (e.g., vitamin C), color agents, and consumption value. If the fruits are overripe it is difficult for pressing, and the process of juice production is inefficient. In addition, one part of the insoluble substances could pass into the liquid part together with the juice, which makes the next operation, centrifugation, difficult due to the increased amount of precipitate. The time and method of the fruit harvest depends primarily on the fruit variety and fruit purpose. Fruit of appropriate quality could be harvested manually or mechanically, depending on the available equipment. Manual harvesting is more commonly used in countries where cheap labor is available and where apple fruit production is organized on the level of relative small orchards. Mechanized harvesting is practiced in developed countries where the big apple orchards are set. Therefore only if the harvest is adequately organized and carried out, could top quality apple fruit be obtained. After harvesting the critical step in the quality juice production is the adequate transportation of harvested apple fruits. Fruits are transported to the factory in bags or crates. The duration of transportation should not be a long time Also during the transportation fruits must not be kept under inadequate conditions (Gvozdenovi´c et al., 2006). If it is possible the fruit juice factory should be located in the immediate vicinity to the fruit producers, to enable fast transportation and decreased harvesting to processing time. The quality of fruit juice is basically determined by the quality of the raw material, since additives must not be added during fruit juice production. Therefore if along with the required fruit quantity, the fruit quality is not taken into account, and if mutual obligations between the producers (of fruit and fruit juice) are not established, safe and highquality fruit production will not be established efficiently or economically (Gvozdenovi´c et al., 2006). Apple fruit reception at the factory is the first operation of the apple fruit juice processing. Reception considers the registration of the received apple fruit amounts, that is, quantity (using technical solutions in the factory, mostly wheel scale) and quality control of the received fruits (raw material and the registration of the variety). The quality control considers the fruit health and ripeness, color, taste, presence of mechanical impurities, etc. For the production of fruit juices, only those raw materials that fulfil the following criteria are allowed: possess appropriate ripeness and taste, have no signs of rotting, and do not contain by-side impurities, pathogenic microorganisms, and products of their metabolism (Barrett et al., 2004; Schobinger, 2001; Sinha et al., 2012).

2.2.1.2 Washing and inspection of apple fruits—the start of apple fruit juice production The aim of apple washing is to remove all types of contamination from the fruit surface, that is, to increase physical, chemical, and microbiological cleanliness. Fruits must be washed well because the surface of the fruit is contaminated with microorganisms, mechanical impurities (sand, ground), and residues of protective agents. On the surface of the fruit, 105
109 microorganisms per gram could be found (Sandhu and Minhas, 2006). By adequate washing the number of microorganisms could be reduced only three to five times. Washing has a significant effect on the efficiency of later thermal treatment, because it reduces the initial number of microorganisms (Barrett et al., 2004; Rajauria and Tiwari, 2017; Schobinger, 2001; Jongen, 2002). Washing is usually performed in two steps: rough and fine. Fruit is roughly washed in the air bubble washing machine. In this first phase, physical and chemical surface contamination is removed, since substances responsible for fruit contaminating are soluble in water or their adhesive characteristics are reduced in water solution. Fine washing usually refers to fruit rinsing with showers in order to remove the compounds from the fruit surface that are left behind after washing. If the fruit is not so dirty, only fine washing with the showers could be applied. The choice of machine for washing depends on the type of fruit. For apples washing equipment with a mixer or water barboting have been used (Barrett et al., 2004; Rajauria and Tiwari, 2017; Schobinger, 2001; Jongen, 2002). The washing effect depends first of all on the washing conditions (pressure, amount of water, time) and on the fruit variety. Washing efficiency could be increased by increasing the water flow, using barbotation, and with the use of mechanical agents. Due to the water flow, a close contact between the surfaces of the fruit parts increases the washing efficiency, but also potentially leads to fruit damage. Therefore when selecting washing equipment, the texture of raw materials must always be considered. The inspection usually follows the washing operation and its aim is to extract those fruits or parts of the fruit that are not suitable for further processing. These could be by-side impurities, parts of the stems and leaves, or moldy, perishable fruit. The inspection is carried out manually and requires special attention, so the necessary conditions must be provided for it (e.g., appropriate lighting and properly installed waste disposal containers). Inspection surfaces should be suitable for rotating the fruit, allowing workers to observe the entire surface of the fruit. This requirement has been filled by roller and strip conveyors.

Apple Chapter | 2

21

2.2.1.3 Milling of apples and primary thermal treatment for apple fruit juice production Milling can significantly affect the yield of juice production. The aim of this phase is to cut the fruit and thus increase its specific surface, which makes juice extraction easier. However, this can lead to enzymatic reactions and to the oxidation of useful components, so fruit must be processed immediately after cutting. Antioxidants (L-ascorbic acid) could be used to prevent the oxidation of the raw material. Apple fruit is shredded on a hammer mill (Lozano, 2006). The shredding breaks down tissue and some cells are damaged, so that the cellular fluid separation begins. If this stage of fruit juice processing is properly done, the fruit is cut into small millimeter-sized, irregularly shaped, homogeneous pieces of nearly identical sizes which under pressure tend to form channels for liquid extrusion. However, if the fruit is milled into very small pieces, it expands under pressure and there is no tendency to form a canal (Horva´th-Kerkai, 2006). In the cases where the mash is treated enzymatically, 4
5 mm apple particles are ideal for the optimum effect of enzyme preparations due to the good contact of the enzyme to the substrate (Brajanoski and Brajanoski, 2004). The main goal of primary thermal treatment is to prevent undesirable changes in the milled mass and to achieve better extraction of colored and aromatic substances from tissue cells. According to Vukosavljevic et al. the primary thermal treatment is carried out in such way to enable fruit mash to quickly heat up, to 85 C
90 C/5 min, and then to quickly cool. This short exposure to a high temperature allows the hydrolysis of protopectins, which influences the softening of the cell walls and increases their permeability, thus accelerating the diffusion of water-soluble substances. This way the enzymes that cause juice darkening (primarily all polyphenoloxidase) have been deactivated, the air has been pushed out of the tissue, and the number of microorganisms has been reduced (Vukosavljevi´c, 2008). If the exposure to high temperature is too long, the tissues become too soft and damaged, which makes fruit pressing difficult, and it also changes the taste. Tubular heat exchangers with three sections are mainly used for heating: the heating section at the set temperature, the section for maintenance of the set temperature, and the cooling section. This equipment allows economical heat usage, since the cold mash is heated in a countercurrent flow with previously heated mash from the third section, and thus achieving also cooling of the heated mash from the third section. The cold mash is heated to 50 C
60 C, and the set temperature of 85 C
90 C is achieved by additional heating with indirect steam. In the zone of temperature maintenance the mash has been kept for 10
30 s depending on the type of fruit, and then has been cooled in the cooling zone up to 45 C
50 C, the optimum temperature for the next operation-depectinization. The cooled fruit mash is being further processed by depectinization (Schobinger, 2001).

2.2.1.4 Mash depectinization in apple fruit juice production Generally in industrial practice, apple mash is usually directly pressed, and depectinized prior to pressing is avoided. Depectinization is the enzymatic treatment of fruit mash with the aim of reducing the viscosity of the mash by degrading pectin substances and enabling easier separation of the juice. In addition to pectin, starch and araban molecules are also degraded, so in this process amylases and arabanases are also used (Rajauria and Tiwari, 2017). In the apple juice production depectinized prior pressing is avoided because apple contains high amounts of polyphenoloxydase that, due to the presence of oxygen and the high concentration of phenolic compounds, causes very fast and intensive darkening of the mash. The final result of this kind of process is the production of dark yellow fruit juice. Yet, there are some cases in apple fruit juice production where the depectinization process is applied. If it is applied than pectolytic preparations, in the form of powder or extract, containing separation enzymes (pectinmethyl esterase, pectinliazum) are usually used to depectinize the mash intended for the production of clear fruit juice. Separation enzymes allow optimum depolymerization (degradation of glucosidic bonds) and deesterification of pectin substances of the fruit and in this way reduce viscosity and stickiness of the mash, which later facilitates pressing, clarification, and filtration of the obtained juice (Zhang et al., 2011). Pectolytic preparations usually contain both cellulase and hemicellulase enzymes, in order to decompose the cell wall and increase the permeability. The optimal amount of pectolytic preparation depends on the quantity and quality of pectinic substances of fruit, pH of the medium, temperature, etc., and is determined by laboratory testing. In practice, the most commonly doses are 0.01%
0.04% of the pectolytic preparation (Vukosavljevi´c, 2008). As the enzymes are in fact molecules made up of proteins, they are heat-sensitive and active only at certain pH values. If the temperature conditions and pH values are not optimal, an increased process time, or a higher concentration of enzymes, is needed for successful depectinization (Horva´th-Kerkai, 2006). The optimal conditions for depectinization are temperatures from 45 C to 50 C, pH of the fruit mash from 3.5 to 4.0, proper mixing in order to achieve a good contact of the enzyme
substrate system, and the optimal amount of the pectolytic preparation. Under optimal conditions depectinization takes 1
2 h. In order to ensure the continuous production, mash has been depectinized at the

22

Valorization of Fruit Processing By-products

depectinization station which consists of three vessels. Continuity in processing is provided, so while the first vessel is being filled in, depectinization is taking place in the second, while the third vessel is being emptied at the same time (Barrett et al., 2004).

2.2.1.5 Pressing of fruit in apple fruit juice production The aim of pressing is to remove the juice from the solid matter of fruit. This is an important technological operation in the production of apple juice; because the quality and utilization of juice depends on it, and therefore the economics of production. In addition to pressing, there are other methods of juice extraction such as extraction, centrifugal process, reverse osmosis, etc., but the pressing is overwhelmingly the most used most in the industry (Rajauria and Tiwari, 2017; Sinha et al., 2012; Schobinger, 2001; Barrett et al., 2004). Pressing considers the application of an external force in order to make pressure and squeeze the liquid. The solid (pomace) has been removed, and the liquid (juice) has been collected in a separate vessel. The most important pressing parameter is the quantity of obtained juice compared to the starting quantity of the raw material (yield). Yield is basically dependent on the type of press, the quality of the fruit and the fruit preparation (degree of ripeness, degree of tissue breakdown, heat treatment, depectinization). In the fruit processing industry continuous and semicontinuous presses are used. In the selection of the type of press the advantage has been given to the one with the higher capacity with continuous operation (Schobinger, 2001; Barrett et al., 2004). Nowadays, the semicontinuous horizontal press is the most commonly used press in the production of apple juices. The most commonly used capacity of this equipment is 5 ton/h, but there are the bigger ones. In this kind of equipment the pressing operations lasts around 90 min, pressure intensity is extremely good because over 200 bar could be applied. The advantage of this press is also production in a closed system, which reduces the possibility of the occurrence of oxidation processes. Generally, for production of quality fruit juice it is important to enable as fast a process as possible, from milling to pressing, in a closed system, so that the raw material is less exposed to air which causes the oxidation processes (Rajauria and Tiwari, 2017; Schobinger, 2001; Sinha et al., 2012). The press basket in this kind of equipment is hermetically closed and there is a beam of properly arranged rubber tubes with the embedded grooves on their surface. The so-called socks with appropriate porosity are pulled on over the pipes. The role of the rubber tubular beam is to prevent mass compaction during pressing, that is, to maintain a loose drainage of mass in the basket and thus accelerate pressing. The role of the socks on the pipes is to filter the juice before entering into the grooves, by means of which the juice will go to the collecting pipeline, where it is removed from the press (Schobinger, 2001). The pressing operation consists of charging the basket and compacting the filled mass, after which the front panel is returned back, the press is stretched, refilled, and again the mass is been compressed. At the end of the pressing, water is added, for the extraction of residual sugar, colored and aromatic substances, which results in better utilization. Automatic discharge of the press is ensured at the end of the pressing. After discharging the press it is filled again. The efficiency of this kind of press is up to 75%. The weaknesses are low capacity, high electricity consumption, and price. Also it is impractical for lower quantities of incoming raw materials and if the press does not work with full capacity, oxidation of the mash occurs. In addition, another disadvantage of this kind of equipment is that it produces the juice consisting of a lot of suspended fine fruit particles, making clarification more difficult (Niketi´c-Aleksi´c, 1988). In the juice industry belt continuous presses (continuous juice extraction and mash importation) are also used. Pressure for pressing is generated between two strips. These presses do not generate high pressures and yield, but they are able to provide high-quality juice production. Juice is separated into several phases and there is no movement of the mash during pressing, which reduces the amount of precipitate and facilitates clarification, that is, filtering juice. At the end of the pressing, the cake is removed from the strip, and the strip in the return path has been washed with water. Juice is taken to the receiving pool by collecting channels. For stripped presses, the yield of about 70% is realized in about 5 min, while the entire pressing cycle lasts around 10 min in total (Brajanoski and Brajanoski, 2004). The advantages of stripped presses are: continuous operation and high capacity (10
20 ton/h), low energy consumption and easy handling. The main disadvantage of this kind of equipment is a small yield, which is about 70% for apple pressing. This deficiency is usually corrected by the extraction of pomace and then by the subsequent pressing of such extracted pomace by a horizontal press, or more often with one more stripped press. In this way, two types of juice are obtained: juice from the first press and juice from the second press. Juice from the second press is of lower quality compared to the first one, since it contains more water. These two juices are mixed and the achieved yield is up to 90% (Rajauria and Tiwari, 2017).

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The pomace produced as a by-product in this phase of juice production is removed from the factory location using a tractor trailer, or it is disposed of in specially built silos and then subsequently removed from the factory. Pomace that is left after direct pressing of apple fruit, contains a high concentration of pectin, and therefore could be used for further pectin production. If the pomace is produced by the process where a phase of depectinization is applied, due to enzyme treatment of the apple mesh and destruction of the pectin, it cannot be further used for pectin production.

2.2.1.6 Further steps in apple juice production: centrifugation, thermal processing of juice, clarification, and filtration The juice obtained after pressing contains a lot of suspended particles and mechanical impurities, so it must be roughly clarified prior to further processing and storage. Suspended particles are removed from the juice using a centrifugal force. In the industry, centrifugal separators
centrifuges, with automatic discharge, are usually used for this kind of rough clarification of juices (Niketi´c-Aleksi´c, 1988). After centrifugation juice is pasteurized by short-term heating for a few seconds at a temperature around 90 C (Niketi´c-Aleksi´c, 1988). This short-term heating reduces the number of microorganisms, inactivates the pectolytic enzymes, aids the juice for depectinization, and coagulates the proteins in the juice, which facilitates the subsequent operations of clarification and filtration (Cohen et al., 1998). The effect of high temperature must be short due to its degradation effect on fruit color and the precipitation of the protein. Juice is pasteurized in plate heat exchangers. The plate heat exchanger consists of rectangular stainless, relief plates. Between the plates is a narrow space where the medium flows through, with an opening at each corner for the input and output of the juice. The large surface of the plates, and the thin layer through which juice flows, allows the fast heating to the required temperature. The plate heat exchangers used in the production of fruit juices have three sections: preheating, temperature maintenance, and cooling. For more economical operation in the preheating section, the juice is heated by heat-treated juice that is simultaneously cooled. Depending on the need, each section can be increased, reduced, or completely turned off, by adding or removing the plates. Hot water or overheated water vapor is used as the most suitable heating medium, which allows the temperature to reach more than 100 C (Niketi´c-Aleksi´c, 1988; Rajauria and Tiwari, 2017; Schobinger, 2001; Barrett et al., 2004; Lozano, 2006; Sinha et al., 2012; Jongen, 2002). The apple juice is usually turbid due to the presence of nonwater-soluble plant residues (fibers, cellulose, hemicellulose, protopectin, starch, and fats) and colloidal macromolecules (pectin, protein, soluble starch fragments, certain polyphenols, and their oxidized or condensed derivatives). In the production of clear juice, these dispersed substances must be partially or completely removed in order to avoid subsequent blurring and precipitation and also to increase the sensory characteristics (taste, smell, and color). But, according to Golding antioxidant activity and phenolic compound content of the final juice product are significantly damaged by the process of clarification during apple juice production (Golding, 2012). Fruit juice can be clarified with physicochemical and mechanical methods or their combination. During the clarification, complex aggregates of macromolecules are formed, and further removed by precipitation. The optimal temperature for high-quality clarification of the juice is 48 C, with a clarification time of 1 h. Higher and lower temperatures do not give satisfactory results of clarification either in terms of reducing the clarification time, or the required amount of clarification preparations (Vasilisin and Grubaˇci´c, 2003). During the process of fruit juice clarification, the so-called protective colloids (pectins, starch, arabans, proteins) must be decomposed, since they prevent the formation of aggregates of dispersed particles and their precipitation. By hydrolysis these macromolecules lose the property of protective colloids; thereby the precipitation of dispersed particles is enabled. In addition to this primary goal, the depectinization has other positive effects on the juice production. The ingredients which arise from the pectin hydrolysis, such as galacturonic acid, stay in the juice, which contributes to giving the juice a greater “fullness.” Pectin hydrolysis decreases the viscosity of the juice and a smaller amount of precipitate is made, and thus the next operation of filtering is facilitated. The required amount of enzymatic preparations needed for this process phase depends on the content of pectin substances. The required amount of pectolytic preparation is exactly determined by the test in the laboratory, and for each juice part separately. The clarification with these preparations lasts 1
2 h, at a temperature of around 50 C (Horva´th-Kerkai, 2006). In the production of clear apple juice, special attention must be paid to the hydrolysis of starch and araban. In the process of physical and chemical precipitation, various chemical compounds have been used. Gelatine and tannin are used in the clarification process. Suspended particles, after carrying out the hydrolytic process, precipitate with the addition of gelatine. Gelatine with tannin forms the complex “tannin
gelatine.” The neutral tannin
gelatine

24

Valorization of Fruit Processing By-products

complex is no longer a stable phase and slowly precipitates, disturbing the balance of the entire system. Precipitating, this complex clumps with other particles which makes clarification easier. To avoid losing the juice taste by removing tannins which bind with gelatine, some tannic acid could be added before clarification. The required quantity of gelatine and tannin is determined by the test in the laboratory. In practice the required amount of gelatine ranges between 0.02% and 0.03%. In the case where the gelatine remains free the juice will be very difficult to clarify; filtering will be difficult, and later on blurring of the juice can occur (Schobinger, 2001). In addition to gelatine, for a more complete and faster precipitation, bentonite is also ordinarily used in practice. This combination gives very good results. Bentonite (clarol), besides having a very specific weight, is negatively electrified and in contact with positively electrified metal cations, it loses the electrified cations and quickly precipitates leaving behind crystal clear juice. This reaction of neutralization of electric discharge of bentonite can also be carried out with gelatine. Bentonite is suspended in water or clear juice and the suspension is added with intense mixing. Most often it takes 700
1500 g/ton of juice (Niketi´c-Aleksi´c, 1988). In the production of clear apple juice, polyvinylpolypyrrolidone can also be used for polyphenols precipitation, or for removing the dark color of apple juice in the process when the apple mash is treated enzymatically. After the process of fruit juice clarification all the particles that make the juice cloudy that have not been separated into precipitate during clarification are removed by the process of filtration. If the clarification and filtration are properly done, subsequently during the storage of the juice there is no precipitation or occurrence of opalescence. For filtering fruit juices bag filters, rough screens, multimedia filters, sediments, or sand filters are most commonly used (Rajauria and Tiwari, 2017). More recently this classic clearing process of clarification is increasingly being replaced by membrane methods: microfiltration and ultrafiltration (Girard and Fukumoto, 1999). These techniques allow simultaneous clarification and filtration. In order to prolong the activity of the membrane, the juice is usually treated with enzymes before the filtration. In ultrafiltration devices the membrane process of the suspension separation is carried out on membranes whose porosity ranges from 1 to 20 nm at a pressure of about 10 bar, where a microporous membrane is used as a prefilter. Today, all modern lines for the production of juice and concentrates of apples give priority to ultrafiltration equipment, as it has been shown that it significantly influences the preservation of the nutritive and sensory characteristics of the obtained juice (Brajanoski and Brajanoski, 2004).

2.2.1.7 Final steps in apple juice production: pasteurization, filling, and storage Fruit juice is preserved exclusively by physical processes, most often using high temperatures, that is, pasteurization. Clear juices can be pasteurized in a continuous process in plate or tubular heat exchangers or after bottling in a tunnel pasteurizer. Pasteurization in the flow is preferable because in that case the juice is briefly exposed to the influence of high temperatures. In the case of using tunnel pasteurizers, the juice is heated up to 82 C
85 C, filled into bottles, closed, and then pasteurized according to the regime of 84 C
88 C/15
45 min, depending on the size of the packaging (Horva´thKerkai, 2006). After treatment with higher temperature, the products are cooled to room temperature, labeled, and stored in secondary packaging. The aseptic procedure is much better for preserving fruit quality. In this case, the juice is pasteurized in flow in a closed system with the regime 100 C
110 C for 0.5
1 min (Horva´th-Kerkai, 2006). After pasteurization, the juice is cooled under conditions where microbial infection cannot occur, and finally it is placed in presterilized packaging. The juice filled into the packaging is kept until delivery in a cool, dry, and dark place at room temperature. During storage undesirable changes in the juice may occur, such as reduced vitamin content, color and flavor changes. Storage temperature is the main factor that influences these changes. The higher the temperature of the storage, the more negative changes are expressed. In addition to reduced temperature, the removal of dissolved oxygen from the juice prior to thermal treatment has a positive effect on the sustainability of taste during storage of the juice. The shelf life of the food is determined by the manufacturers themselves and most manufacturers declare the expiration date of clear fruit juice to be up to 1 year (Ashurst et al., 2017). Juice is aseptically stored in tanks of 20
30 t until placed into commercial packaging. Fruit juices are most often sold in commercial packaging made of combined materials (cardboard, plastic, metal), cans, or jars. In addition to these packaging materials for fruit juices, PET packaging is also used, but to a much lesser extent. In the case of jars, after pasteurization the juice is not cooled, but it is placed in preheated water-washed packaging. The charging temperature is 95 C and in this way the packaging units have been sterilized. After filling, the packaging units are closed and transported into a cooling tunnel which is divided into three sections. In the first section, the juice

Apple Chapter | 2

25

is cooled to a temperature of 75 C, in another to 46 C, and in the third to 31 C. After cooling, the packaging is dried on a device that blows cool air, after which it is labeled, packaged, and stored at room temperature. In the case of cans, after pasteurization in a plate pasteurization at 97 C, the juice is cooled to 30 C
35 C and placed in previously washed cans. After pasteurization, liquid nitrogen is added to each can, and the cans are closed. Hermetic sealing of the packaging is achieved by mechanical closing. After closing, the cans are transported to subsequent pasteurization in a tunnel pasteurizer at 91 C, which for a clear juice lasts 35 min. After pasteurization, the cans go to the cooling section where they are kept for 10
15 min and cooled to 35 C. In the case of multilayer packaging, after pasteurization, the juice is transported to the fillers by the pipe system. After the section for recovery, it is necessary to perform deaeration. Clear fruit juice is filled at a temperature of 25 C. Juice is filled in aseptic conditions, so it is necessary to ensure asepticity in the chambers before the start of filling. Asepticity is achieved by hot air and the use of hydrogen peroxide. After achieving aseptic conditions in the chambers, the filling starts. Liquid nitrogen can also be used when filling in order to ensure the firmness of the packaging and to prevent oxidation processes by oxygen removing.

2.2.2

Concentrated fruit juice production

Fruit juices contain a high percentage of water, which is usually between 80% and 85%. High water content negatively affects the changes in the juice during processing and storage, and significantly increases the costs of the storage and transport of juice. The most visible changes are reflected in the aroma of fruit juices that is lost to a lesser or greater extent, despite careful processing and storage (Lozano, 2006; Su and Wiley, 1998). These problems in the fruit juice industry are overcome by concentrating fruit juice. Concentrated fruit juices are produced by the physical separation of a certain amount of water from fruit juice (Council Directive 2012/12/EU, 2012). Apple juice is thin in nature and can be concentrated five to seven times (Rajauria and Tiwari, 2017). The goal of the concentration process is the removal of water, whereby the changing of nutritional and sensory properties of the products should be minimized. By removing water, the volume of the juice decreases, which reduces the requirements for storage capacities and reduces transport costs. In addition, concentrated fruit juice is more easily protected from undesirable changes. During concentration, the aroma from fruit juices is separated and stored in special conditions, apart from the fruit juice. The water activity (aw) of the fruit juice decreases during the concentration from 0.73 to 0.94 (Schobinger, 2001), and the remaining fruit concentrate is stabilized to a large degree in chemical and microbiological terms. Thus by concentrating the fruit juice, the typical aroma of the juice is preserved, and at the same time the volume for storing and transporting concentrated juice has been multiply reduced. In order to avoid aroma loss during concentration, before clarification the apple juice is dearomatized, by partially concentrating the juice. The apple aroma is easily separated and for the aroma separation it is necessary to evaporate around 20% of the initial volume of the juice (Dixon, 1999). During dearomatization, the secondary vapors with aromatic components are separated and taken to the rectification column, and then for further purification and condensation, and the dearomatized juice goes to concentrating. The flavor is concentrated to a concentration degree of 1:100 to a maximum of 1:200 and stored at around 0 C (Schobinger, 2001). The most economical and currently the most widely used method for concentrating fruit juices is the separation of water by evaporation in a vacuum. The application of freezing and reverse osmosis concentration has no significant application on an industrial scale. Physicochemical properties such as total phenolic compounds and antioxidant activity are successfully preserved using osmosis concentration for the concentration of juices (Kujawski et al., 2013; Gunko et al., 2006; Zambra et al., 2015). The apple juice concentrates to around 70 Bx. Since most juices are sensitive to heating, evaporation is generally carried out at reduced pressure (vacuum), whereby the boiling point of the product decreases and evaporation occurs at lower temperatures. The juice is concentrated in a vacuum in a single-step, two-step, or multistep evaporator. The concentration temperature is usually 40 C
45 C, and if it is higher in the first phase of a two-step or multistep evaporation, then the time must be very short, from 10 to 30 s (Niketi´c-Aleksi´c, 1988). In low-temperature evaporators the evaporation temperature in the first step is around 18 C and in the second 33 C. The lower the temperature and the shorter time are, the safer it is to preserve the color and produce concentrated juice with a pleasant taste. Concentrated juice is pasteurized in a flow-through plate or a tubular pasteurizer at a temperature of 85 C for 30
40 s, or at a higher temperature of 100 C
105 C for only 10 s and storage tanks are filled in aseptic conditions (Niketi´c-Aleksi´c, 1988).

26

Valorization of Fruit Processing By-products

2.2.3

By-products of apple fruit juice production

Apple juice production belongs to the branches of industry that produce large quantities of by-products in relation to the initial amount of processed fruits, estimated at 25% (Mahawar et al., 2012). Several by-products of this processing food sector are targeted as the most important; these are apple pomace, apple peel, and apple seed.

2.2.3.1 Apple pomace Apple pomace is the most important by-product of apple fruit processing. Apple pomace presents approximately 25% of the fresh weight of apple (O’Shea et al., 2012) that is left behind after the processing apples for different products (Petrovi´c, 2018). The annual production of apple pomace in the United States and Germany amounts to around 1.3 and 0.25 million metric tons, respectively (Wang and Thomas, 1989; Oreopoulou and Tzia, 2007). In 2010 the overall global apple pomace production was expected to exceed 3600 kton/year (Kammerer et al., 2014). Apple pomace is mainly composed of skin and flesh (95%), seeds (2%
4%), and stems (1%) (Perussello et al., 2017). According to O’Shea et al. (2015) apple pomace contains 9.0% moisture, 2.27% fat, 2.37% protein, 1.6% ash, 84.7% carbohydrate, 5.6% starch, and 54.2% total sugar, as well as high quantities of calcium, potassium, and magnesium. Apple pomace consists of approximately 10%
15% pectin on a dry weight basis (Endress, 2000; Wang et al., 2007). Thus it presents very important material for the production of pectin. Considering the high level of pectin in apple pomace, there are lot of papers investigating its extraction, such as research by Canteri-Schemin et al. (2005) and Wang et al. (2007). Besides pectin, apple pomace is also considered as a good source of nutrients since it is rich in carbohydrates, crude fibers, and minerals (Shalini and Gupta, 2010). According to research by Dhillon et al. (2013b) apple pomace contents 6.8 g/kg total nitrogen, 127.9 g/kg total carbon, 7.2%
43.6% (w/w) cellulose, 4.26%
24.40% (w/w) hemicellulose, 15.3%
23.5% (w/w) lignin, 3.5%
14.32% (w/w) pectin, 48.0%
83.8% (w/w) total carbohydrates, 4.7%
51.10% (w/w) fiber, 2.9%
5.7% (w/w) protein, 1.20%
3.9% (w/w) lipids (ether extract), 10.8%
15.0% (w/w) reducing sugars, 22.7% (w/w) glucose, 23.6% (w/w) fructose, 1.8% (w/w) sucrose, 14%
23% (w/w) arabinose, 6%
15% (w/w) galactose, and 1.1% (w/w) xylose. According to Rana et al. the total dietary fiber yield in industrial apple pomace is calculated to be 74% (Rana et al., 2015). Some other bioactive compounds have been also found in apple pomace, these are polyphenols (Wang et al., 2014; Bai et al., 2010; Pingret et al., 2012) and syloglukan (Fu et al., 2006). According to the research of Soares et al., 16 phenolic acids were identified in apple pomace samples (Gala and Fuji cultivars). The content of free phenolic acids in apple pomace from Gala cultivar was 29.11 mg/g and the following acids were identified: salicylic, protocatequinic, quinic, p-coumaric, gallic, propylgallate, and sinapic. The content of free phenolic acids in apple pomace from Fuji cultivar was 16.03 mg/g and the following acids were identified: salicylic, protocatequinic, gallic, ferulic, and sinapic (Soares et al., 2008). According to the same research salicylic was the predominant free phenolic acid found in both cultivars, consisting of 91.67% and 63.57% of the free phenolic acids in Gala and Fuji cultivars, respectively. Chlorogenic acid (1.147 mg/g) was found only in apple pomace from Fuji cultivar. The predominant esterified phenolic acid in pomace from Gala cultivar is derived from salicylic acid (52.76 mg/g). Acids derived from gallic acid (0.175 mg/g), propylgallate acid (0.198 mg/g), ferulic acid (0.159 mg/g), and sinapic acid (0.140 mg/g) were also found in Gala cultivar. Regarding pomace from cultivar Fuji, the main esterified phenolic acid found is also derived from salicylic acid (47.42 mg/g) followed by gallic acid (0.270 mg/g), benzoic acid (0.194 mg/g), and sinapic acid (0.115 mg/g) (Soares et al., 2008).

2.2.3.2 Apple peel Apple peel is a compound of apple pomace, but it is also separately generated during the production of apple sauce, fresh-cut apple, dried apple, and canned apple. According to Perussello et al. (2017), the quantity of this generated peel is around 13% of the input raw material. According to Wolfe and Liu (2003) apple peels were typically used for nonvaluable purposes. They, along with the core materials, are often pressed to make juice or vinegar, pressed into a cake for livestock feed, or used as fertilizer. Sometimes they were used as a source of pectin. Today apple peel is an interesting by-product of apple processing because of the high concentration of phenolic compounds. According to several authors the concentration of total phenolic compounds is much greater in the peel of apples than in the apple flesh (Burda et al., 1990; Ju et al., 1996; Escarpa and Gonza´lez, 1998; Wolfe and Liu, 2003). According to Wolfe and Liu (2003) the nature and distribution of these phytochemicals between the flesh and the peel of the apple is different. Among others, the flesh contains catechins, procyanidins, phloridzin, phloretin glycosides, caffeic acid, and chlorogenic acid; the peel possesses all of these compounds and has additional flavonoids not found in the flesh, such as quercetin glycosides and cyanidin glycosides (Burda et al., 1990; Golding at al., 2001; van der Sluis et al., 2001). In their study Escarpa and

Apple Chapter | 2

27

Gonza´lez (1998) reported a higher ratio of chlorogenic acid relative to caffeic acid in apple peel and pulp (flesh). Tsao et al. (2003) conducted research on eight apple cultivars: Golden Delicious, Red Delicious, McIntosh, Empire, Ida Red, Northern Spy, Mutsu, and Cortland. They identified 16 polyphenolic compounds belonging to all five major polyphenolic groups from the eight popular Ontario apple varieties. In the pulp the total polyphenolic concentrations analyzed by high-performance liquid chromatography (HPLC) were significantly lower compared to that of the peel. Among the five major groups, the procyanidins predominated in both the peel (59.7%) and the pulp (55.7%). In the same study two monomers, catechin and epicatechin, and two dimers, procyanidins B1 and B2, were identified from the peel and pulp of apple.

2.2.3.3 Apple seed and other apple by-products Apple seed, just like apple peel, is a compound of apple pomace. The share of seeds in apples depends on the cultivar and may be as high as 0.7% of fresh fruit (Fromm et al., 2012). According to Perussello et al. (2017) apple seed can be generated by sieving apple pomace and the quantity is around 4%
7% calculating on pomace. According to the work of Yu et al. (2007) apple seeds are rich in oil and protein, ranging from 27.5% to 28% and 33.8% to 34.5%, respectively. GC analysis of apple seed oil indicated high levels of linoleic acid (around 49%) with the other dominant fatty acids being oleic, palmitic, and stearic acids. Go´rna´s et al. (2014) investigated the oil yield in the apple seeds of crab and desert apple, and found out that it ranged from 12.06 to 27.49 g/100 g dry weight base. The average level of oil obtained from crab apple seeds was higher by 30%. The fatty acid composition was dominated by palmitic acid (5.78%
8.33%), oleic acid (20.68%
29.00%), and linoleic acid (59.37%
67.94%). Among the six detected phytosterols β-sitosterol was predominant (51%
94%). Yu et al. analyzed the amino acids in the apple seed and found that there are substantial amounts of sulfur-containing amino acids in this by-product. The apple seeds also contain significant amounts of phosphorus, potassium, magnesium, calcium, and iron, in the order of 720, 650, 510, 210, and 110 mg/ 100 g, respectively (Yu et al., 2007). The target of the study of Bolarinwa et al. (2015) was the content of amygdalin in apple seeds from 15 varieties of apples. According to the results of this study the content of amygdalin in this apple byproduct ranged from 1 to 4 mg/g. Due to the high amygdalin content the authors recommended that apple seeds should be removed before consumption or apple processing.

2.2.4 Other apple processing—apple-containing fruit filter tea production and by-product remaining Nowadays, different varieties of medical plants, fruit, and herbs, are being used in the form of herbal/fruit tea. The majority of herbal/fruit teas are present in the market in the form of herbal/fruit filter tea. During the production of herbal/fruit filter tea (Fig. 2.2), operations like cutting, grinding, sifting, and fractionating are applied (Vidovi´c et al., 2013; Naffati et al., 2016). Fig. 2.2 depicts the process of raw material processing in the herbal filter tea production. The main aim of the first of several mechanical operations, followed by fractioning, is the production of “fine cut.” According to Naffati et al., “fine cut” is herbal material of particle size from 0.315 to 2.0 mm, and represents the fraction of the processed material (herb or fruit) that is further used for herbal/fruit filter tea production (Naffati et al., 2016). According to Vladic et al., during the industrial processing of herbs or fruits in a herbal/fruit filter tea factory, a high amount of herbal and fruit by-product/waste is produced. The amount of such material ranges from 10% to 40%. The most important by-product/waste obtained during such industrial processing is the so-called herbal/fruit dust (Vladi´c et al., 2017), produced after fractionation, and of a particle size lower than 0.315 mm. Herbal material of a particle size lower than 0.315 mm cannot be used in the production of filter tea because the particle size of such material FIGURE 2.2 Flowchart of fruit/ herbal filter tea production.

28

Valorization of Fruit Processing By-products

is smaller than the pores of the filter bag. Thus this kind of material is discharged from the production as a by-product and/or waste (Naffati et al., 2016). The filter tea industry generates a wide range of various herbal and fruit dusts, as it processes many different kinds of plant materials. The quantity of some of them, for example, apple, is significant and varies from region to region. During the apple processing in the filter tea factory, approximately 20% calculated on input raw material of apple fruit dust is produced (Naffati et al., 2016). Input raw material in this kind of apple processing is dried apple with the peel, or dried apple pomace. Bearing in mind the quantity of this by-product and the quality of wild apple (biological activity and chemical composition), it is easy to target the wild apple fruit dust as a byproduct worth being “recycled.” One of the best ways to utilize this kind of material is through the application of solid
liquid extraction (Naffati et al., 2016). According to the results obtained in the study of Naffaty et al. the total phenols content in the wild apple fruit dust ranged from 777.003 to 1148.030 mg gallic acid equivalent (GAE)/100 g of the investigated material, and therefore the authors indicate the high potential for the utilization of this kind of material for the production of extracts with a high concentration of phenolic constituents (Naffati et al., 2016).

2.3

Possibilities of application of apple processing by-products

Applications of apple processing by-products are mostly focused on the application of apple pomace. This is probably due to the high quantity of generated pomace, but also probably due to the beneficial chemical composition of this kind of material. Previously, apple pomace was mostly treated as waste which was often deposited directly in landfills. But, due to the ecologically unacceptable side of this (Shalini and Gupta, 2010), and due to the fact that apple pomace is a rich source of sugar, dietary fiber, minerals, and phenolic compounds, investigation into the possibilities of apple pomace applications have been increased. Up to now various applications of apple pomace and other apple by-products were reported. In order to lower costs related to waste processing, apple pomace is traditionally used as a crude feed, a concentrate feed, or a forage extender for livestock despite its low protein content and less metabolizable energy content in comparison with corn silage, with a yield similar to an average quality hay but with the main function of energy replacement (Perussello et al., 2017; Rust and Buskirk 2008; Zhong-Tao et al., 2009). The higher quantity of antinutritive compounds, that is, tannins, is alongside the low protein content, one of disadvantages for the application of apple pomace as animal feed. However, properly processed and preserved pomace could substitute for corn, barley, and other grains in animal feeding. The latest experimental studies have shown numerous positive results in this field: daily growth, yield of meat, quality of halves, mass of the heart, liver, spleen, small intestine, development of lymphatic tissue of digestive tract, morphology of intestinal villi, general health condition, as well as the decrease of mycotoxin absorption in the small intestine of animals (Maslovari´c, 2017; Pieszka et al., 2017; Gutzwiller et al., 2007). Maslovari´c (2017) concluded that dried apple pomace can successfully be used in industrially produced animal feed mixtures, that is, it can substitute for other animal feds, leading to economical production, preservation of natural resources, and environment protection. The author also concluded that pelleting of apple pomace enables simpler and more efficient storage and transport, with a positive effect for the pelleting process and the quality of pellets (Maslovari´c et al., 2017; Maslovari´c, 2017). The author suggested apple pomace could be a component in animal feed mixtures, in amounts from 5% to 20%. One of the first applications of apple pomace was linked to the use of apple pomace for composting (by aerobic microbial deconstruction). This way a high-quality compost was produced, and as such could be considered as a successful replacement for fertilizers and as a soil quality meliorator. One of the latest studies is showing that the application of the apple pomace amendment compost could improve the yield and trace element nutrient accumulation in Chinese cabbage when planted in a typical Zn-deficient soil. This study illustrates that apple pomace application benefits both compost nitrogen conservation and fertilizer quality (Mao et al., 2017). Owing to the high carbohydrate content, apple pomace was used as a substrate in a number of microbial processes for the production of organic acids, enzymes, single cell protein, ethanol, low-alcohol drinks, and pigments (Bhushan et al., 2008). There are also some attempts at apple pomace bioconversion into a product of higher nutritive value, owing to the activity of different microorganisms (Maslovari´c, 2017; Bhalla Joshi, 1994; Villas-Boˆas et al., 2003; Joshi et al., 2000; Vendruscolo et al., 2008). Dhillon et al. (2013a) made full use of the apple pomace by employing it to produce citric acid by fermentation using fungal mycelium followed by further extraction of chitosan as a coproduct from the fermentation waste. In another fermentation the apple pomace carbohydrate fraction was hydrolyzed by enzymes (e.g., cellulase and hemicellulase) generated by incubated cultures such as Saccharomyces cerevisiae MTCC 173 to produce biofuels like bioethanol (Perussello et al., 2017). According to Evcan et al. the utilization of apple pomace for the production of bioethanol can lead the way to producing value-added products from low-cost agroindustrial wastes and provide an alternative solution to the

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accumulation of lignocellulosic wastes whose disposal is a primary problem of the fruit juice industry (Evcan and Tari, 2015). Evcan and Tari (2015) produced bioethanol from apple pomace hydrolysate using cocultures of Trichoderma harzianum, Aspergillus sojae, and S. cerevisiae which showed better sugar and carbohydrate consumption profiles. The highest bioethanol concentration and ethanol yield in total reducing sugar content were 8.748 g/L and 0.945 g/g, respectively. Ucuncu et al. (2013) explored the potential use of apple hydrolysate and the fungus T. harzianum in bioethanol production. They confirmed that apple pomace holds potential for bioethanol production. The highest reducing sugar yield from the optimization step for apple pomace was 31% under optimum hydrolysis conditions. Beside these applications of apple pomace, the possibility of the application of apple pomace in the bakery industry, in the production of biscuits and related products was also investigated (Wang and Thomas, 1989; Petrovi´c, 2018). According to Petrovic, due to the appealing aroma, it is possible to reduce the amount of sugar that has to be added in certain products by adding the certain amount of apple pomace (Petrovi´c, 2018). With the addition of apple pomace in different biscuits, a characteristic aromatic flavor and darker color are produced. Accordingly, in research by Jozunovi´c (2015) it was concluded that the addition of this by-product in corn meal, as well as in the extrusion process, had a significant effect on color parameters, with the most significant total color change (ΔE) recorded in samples with apple pomace. Since the values of ΔE were greater than 6 in all mixtures and extrudates, regardless of the applied byproduct, this represents a significant visible color change. A study of a similar application but using apple peel was provided by Vasantha Rupasinghe et al. (2009). In this study the baking and sensory characteristics of muffins incorporated with apple skin powder were investigated and it was concluded that replacing an equivalent amount of wheat flour with apple skin powder up to 16% in muffins resulted in an acceptable sensory quality. Due to its valuable chemical composition (Rabetafika et al., 2014; Dhillon et al., 2013a), apple pomace can be considered as a good source of antioxidants ´ (Cetkovi´ c et al., 2008) and fibers in crackers, cakes, and biscuits, being at the same time a natural flavoring and healthpromoting functional ingredient (Sudha et al., 2007; Mir et al., 2017; Rana et al., 2015; Kammerer et al., 2014). In addition, lactic acid bacteria immobilized in apple pomace matrix could improve the production of functional bread (Bartkiene et al., 2017). Due to the aforementioned chemical characteristics of pomace, producers are also given an opportunity for a relatively simple way to reuse of pomace in the production of semiproducts, which, by appropriate process control, could be used in the production of cheaper jelly products, with the quality standard maintained (Tepi´c et al., 2011). Despite the numerous successful applications of apple by-products, especially apple pomace, still the most important application of apple pomace in the first place, and then all others apple by-products, is in the production of pectin and in the extraction of valuable compounds, such as phenols. Apple pomace is mostly used for the production of pectin and this represents one of the most practical and the most widespread approaches for the valorization of apple byproducts (Bhushan et al., 2008).

2.3.1

Pectin

2.3.1.1 Importance of pectin Pectic substances are natural, plant-origin compounds. As structural elements of plant tissue and the main constituent of the middle lamellae, they provide cohesion and stability to plant cells and tissues. Citrus peel, apple pomace, sugar beet chips after sugar extraction, and sunflower heads are the raw materials that contain high amounts of pectic substances and can be used for its production. Different raw materials can give different amounts of extractable pectins: apple pomace 15%
18% (cultivated apple pomace) to 30%
40% (wild apple pomace); beet chips 20%
30%; sunflower ˇ heads greater than 25%
35%; citrus peel 30%
45% (in dried material) (Sulc, 1969). Pectic substances are natural compounds found in primary cell walls as an important structural element. They are found in greatest concentrations in the middle lamella, which forms a supportive layer between fruit and vegetable cells. Pectic substances act as binding materials with a supportive and stabilizing role. They are complex colloid carbohydrate derivatives, containing high moieties of anhydrogalacturonic acid units bound in a polymeric chain. D-Galacturonic acid monomers are bound with α-1,4-glucosidic bonds, forming linear polymers. Carboxylic groups of these polygalacturonic acids may be high-, middle-, or low-esterified with methanol, or amidated. Free carboxylic groups may be partially or completely neutralized with one or more alkali. They have a colloid character, that is, high molecular weight. Along with pectic substances there are ballast materials bound to pectins, or as attendants (pentoses, ˇ pentosans, hexoses, hexosans, and cellulose) (Sulc et al., 1985). Pectic substances can be classified as protopectin, pectinic, and pectic acids. Protopectin consists of polymerized pectic substances, bound to cellulose, hemicellulose, lignin, and sugars. Pectic acids involve totally deesterified pectinic

30

Valorization of Fruit Processing By-products

acids. These are polygalacturonic acids with no methoxy groups. Pectinic acids are colloid polygalacturonic acids with methyl ester groups. These compounds are capable of forming jellies in appropriate conditions (with sugar and acids, or with calcium ions). Pectinic and pectic acids are derived from protopectin (the water-insoluble fraction) by limited hydrolysis (maturation, ripening, overripening, and acid hydrolysis). Pectin is a common name for water-soluble pectinic acids. Pectins are thus methyl esters of polygalacturonic acid, with a colloid character, of different degrees of esterification, with gelling potential. The behavior of pectin in fruit and vegetable processing is influenced by the molecular weight (degree of polymerization), degree of esterification, and colloidal-chemical features (coagulation, swelling, solubility, viscosity, and gelling properties) (Vujiˇci´c, 1975). Owing to their high molecular weight (100,000
300,000), pectins are referred to as natural high molecular weight compounds. Increase of pectin molecular weight (degree of polymerization) causes an increase in viscosity of the pectin solution, swelling, gelling, dispersion, alcohol and electrolyte coagulation capacity, and the stability of methoxy groups toward alkali, causing a decrease in water solubility at the same time. An increase in degree of esterification causes an increase in water solubility, solution viscosity, gelling time, and tolerance toward sugars, causing a decrease in pectin acidity, sensitivity toward electrolytes, and coagulation capacity with acids and neutral salts. Pectins are water soluble up to a maximum of 10%. Pectin water solubility increases with the increase of degree of esterification, and decreases with the degree of polymerization (molecular weight). Pectin solutions in water exhibit high viscosity, which is a very ˇ important feature for the stability of different products (fruit juices, purees, etc.) (Sulc, 1969; Vujiˇci´c, 1975). According to gelling properties and the degree of esterification, pectins can be categorized into two groups: G

G

High-esterified (HM) pectins, contain more than 50% of esterified units of galacturonic acid, that is, contain 7%
13.2% of methoxyls. Degree of esterification correlates with the gelling time and gel texture. This means that very HM pectins have shorter setting time. HM pectins are used in the production of jellies with a high amount of sugar. Sugar content in jellies with HM pectins should be no less than 55%. Low-esterified (LM) pectins, contain less than 50% of esterified units of galacturonic acid. In contrast to HM pectins, LM pectins are generally independent of the sugar and acid content. LM pectins form gels in the presence of calcium ions. They are generally used in low-sugar fruit preparations for bakery, dairy products, and fruit spreads. The fact that LM pectins form jellies in low-sugar conditions opens numerous possibilities for their application (Vujiˇci´c, 1975; www.herbstreith-fox.com).

2.3.1.2 Production of pectin from natural sources Although pectic substances originate in many plants, only a few are used for their isolation. The main reason is that many pectic substances in plants are not suitable for the production of preparations with jellying properties. Primary raw materials for the isolation of pectic substances are apple pomace and citrus peel. The secondary materials are sunˇ flower heads, grape husk, beet chips, and tropical plants (Sulc et al., 1985). As previously said, apple pomace is a by-product of apple juice processing. The quality of pomace is influenced by apple variety, climate conditions, growing conditions, maturity stage, and the pomace obtaining procedure. Apple varieties grown in northern regions are the best varieties for pectin isolation, as they achieve maximal maturity slower, one of the important factors for quality pectin production. Firm tissue apples give pectins of better quality in comparison to soft apples, in which the pectin has been degraded. Firm apples contain undegraded starch. If the maturity is in an advanced stage, the starch is decomposed and is a ballast that has to be removed during the production of pectin. A number of scientific manuscripts and reviews have been published on the topic of the valorization of by-products and waste through the application of conventional and innovative processing techniques for the extraction of pectin ˇ (Sulc, 1969; Schieber et al., 2003; Mari´c et al., 2018; Wikiera et al., 2015a; Kumar and Chauhan, 2010; Wang et al., 2014; Perussello et al., 2017; Adetunji et al., 2017; Sundarraj et al., 2018; Bhushan et al., 2008). Raw material released from pectin is dried and pressed into pellets. Due to their high energy and nutritive value, these remains can be used for animal feed. In order to get high-quality pectin from pomace, raw materials have to be hydrolyzed and processed as soon as possible. If not possible, they have to be dried to a maximum of 8% humidity, and stored in appropriate conditions (large, dry, and airy warehouses with controlled temperature and humidity). If the raw material is not being processed immediately, it is prone to microbial and enzymatic degradation. This kind of material is not suitable for further processing. Fresh pomace has to be processed in less than 3 h after obtainment, as it is prone to quality loss (in 12 h it can lose up to 50% of quality). Production of pectin extract and pectin powder takes place in the following phases: protopectin hydrolysis (pectin extraction), concentrating the pectin hydrolysate (pectin extract production), and processing of pectin extract to pectin powder. Before the protopectin hydrolysis it is necessary to wash out the apple pomace well, in order to remove

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water-soluble contents (sugars, acids, pigments, etc.). These materials would increase total solids and the degree of contamination in pectin hydrolysate. After washing out the pomace, protopectin has to be hydrolyzed (i.e., pectin to be extracted). This is probably the most important phase in the process of pectin preparations production. As pectin substances are present in the form of protopectin in the pomace, it is necessary to hydrolyze the protopectin and transform the pectin into a soluble state. By combining the parameters that influence the pectin hydrolysis efficiency (quality and the state of pomace, pH of the solution, temperature, time, quantity, the purity of the water for the extraction, etc.), the optimal conditions of hydrolysis and extraction can be determined from case to case. Protopectin hydrolysis and pectin extraction is guided in order to gain maximum protopectin hydrolysis, with minimal degradation of released ˇ pectin (Sulc, 1969). ˇSulc (1969) proposed the following procedure for efficient protopectin hydrolysis and pectin utilization. The procedure enables the efficient hydrolysis of insoluble protopectin into a soluble pectin. Temperature, acidified environment, and time are the main parameters to enable good utilization and high-quality pectin. Beside hydrolysis, a diffusion process also takes place, which enables the isolation of pectin from apple pomace. Leached apple pomace has to be infused with 10-fold acidified (tartaric acid with addition of sulfurous acid—for gaining lighter color, as well as sodium hexamethaphosphate—for facilitating extraction and solubility of pectin by making complexes with calcium and magnesium salts) soft water (pH 2.8). The process of protopectin hydrolysis (i.e., pectin extraction) should take place in extractors with agitator and heater. The bulk is then heated up to 70 C, left to stand with constant and slow mixing for 10
12 h (as long as it takes for the liquid to gain 2.2%
2.5% of soluble solids, measured using refractometer). Pectin hydrolysate is then released from the extractor and the exploited pomace is washed out with water. Washing water is mixed with hydrolysate (which now has some 1.8%
2% of soluble solids). Obtained pectin hydrolysate has to be clarified and filtrated, then concentrated to 8%
10% of soluble solids, in order to get pectin extract. Powdered pectin is produced by spray drying or vacuum drying of the pectin extract. ˇ According to Sulc (1969), much better products may be obtained by the precipitation of pectin from pectin extract using alcohol or aluminum salts. Precipitated pectin is then washed out with acidified alcohol, to remove the chlorine ions, and then it is dried and ground to powder. Eighty to hundred kilograms of pectin powder (with minimum 75% of clear pectin) can be produced from 1 t of dried apple pomace. The main problem in LM pectin production is the optimal deesterification of pectin polymer, with minimal degradation of the molecular chain. This means that the degree of esterification of molecules produced this way should not be higher than 45%, otherwise they would be close or similar to HM pectins. On the other hand, the degree of esterification of these pectins must not be low, that is, lower than 40%, or the solubility will be very poor, and the structure will be close to pectic acid (i.e., molecule will lose its colloidal properties, as well as the ability to form gels). The molecular weight of LM pectins must not be under 150,000. Pectin deesterification should be conducted by the use of acids, alkalis, or enzymes (pectases). Acids and alkalis act randomly (producing homogenous products), while pectases act at the end of the molecule, which can cause that part of the pectin molecule to become totally deesterified, while at the same time the other part remains highly esterified (causing inhomogeneity). Acid deesterification (at pH 0.7) causes not only deesterification, but the depolymerization of pectin molecule (to a molecular weight of about 60,000), while alkali deesterification (at pH 10) causes optimal deesterification and slight depolymerization of the pectin molecule (molecular weight of around 200,000). Thus alkali deesterification can be applied for LM pectin production. This procedure was described in the following steps: 5% pectin solution (with pH 10) is kept cool (c.10 C) for 4 h; then hydrochloric acid is added (to pH 7) and pectin is precipitated with acidic alcohol. The precipitate is then washed out with alcohol (until a negative reaction to chlorine ions) and dried in a vacuum drier. The dried precipitate is then ground to powder and kept in hermetically sealed containers in a dry and cold place. The above proposed method for pectin extraction is probably one of the first proposed techniques. Other authors have proposed pectin extraction by applying hot acid methods (Waldbauer et al., 2017; Wang et al., 2014). However, concerns regarding acidic wastewater and environmental pollution contributed to the development of alternative methods for the extraction of pectin (Wang et al., 2014). Enzymatic extraction appears to be a more auspicious option. Enzyme preparations that are commercially available consist of mixtures of cellulases and proteases. Performed under optimal conditions, this type of extraction provides higher yields compared to an acidic extraction. The cell wall lamellae are broken down to free the water-soluble pectin (Waldbauer et al., 2017; Wikiera et al., 2015a). In addition, other methods for the extraction of pectin from apple pomace have included Microwave-assisted extraction (MAE) (Wang et al., 2007) and ultrasound-assisted extraction (UAE) (Zhang et al., 2013), and extrusion (Shin et al., 2005). Moreover, in a study by Wang et al. (2014) subcritical water was used to extract pectin polysaccharides from apple pomace, confirming the effectiveness of the process. Extracted pectin showed a lower viscosity, dry matter, and protein content, whereas the ash and neutral sugar content were higher. Furthermore, in vitro antioxidant activity of

32

Valorization of Fruit Processing By-products

extracted pectin was higher than the activity demonstrated by the commercial pectin. Wang et al. (2014) also used subcritical water for the extraction of pectin from apple pomace. The results of their study showed that subcritical water can be successfully used for the extraction of pectin, without acid or alkaline addition. In addition, the extracted pectin displayed significant antioxidant and antitumor activity.

2.3.2

Valorization of apple by-products through antioxidants extraction

The presence of highly significant bioactive compounds in apple by-products and waste has been confirmed in numerous studies. Some of the beneficial health effects of apple by-products and waste include antioxidant, antiproliferative antiinflammatory, antibacterial, and antiviral activities (Waldbauer et al., 2017; Grigoras et al., 2013; Sua´rez et al., 2010; Sa´nchez-Rabaneda et al., 2004; Lu and Foo, 1997, 1998, 1999, 2000). Therefore by using apple by-products it is possible to extract those valuable compounds which can be applied in different industries, such as the pharmaceutical, cosmetic, and food industry. Also the valorization of by-products can lead to improvements in production process efficacy through increasing the exploitation of the raw material, setting up sustainable production, and reducing waste generation. For those purposes, a large number of studies have been conducted and they deal with finding and determining the most efficient and feasible extraction processes that can maximally exploit apple by-products for the recovery of polyphenol compounds. Depending on the industry, apple pomace can consist of apple peels, leftover flesh, core with seeds, and stems (Waldbauer et al., 2017). Applied traditional extractions mostly involved maceration or the Sohlet extraction with different organic solvents: methanol, acetone, ethanol, ethyl acetate, and their mixtures with water (Wijngaard and ´ Brunton, 2010; Sua´rez et al., 2010; Garcı´a et al., 2009; Cetkovi´ c et al., 2008; Foo and Lu, 1999). Conventional techniques of extraction are very often time- and energy-consuming, and the solvents used are nonselective. Moreover, organic solvents have a negative impact on human health and the environment. The removal of organic solvents represents an additional step in the production of extracts which further increases the costs of production. The main goal is to decrease the process expenses and at the same time increase the quality and safety of the obtained products by using safe green technology and solvents. Alternative technologies that have been developed to meet the aforementioned conditions are UAE, MAE, subcritical (SWE), and supercritical fluid extractions (SFEs). Table 2.1 shows the studies in which conventional and modern methods of extraction were used for valorization of apple by-products along with setup conditions of the extraction process. In the study by Candrawinata et al. (2015), the authors investigated the potential alternative to using organic solvents and optimized the extraction of phenolic compounds from apple pomace by using water as a solvent. Extractions were conducted under the following conditions: time 15
30 min, temperature 85 C
95 C, and pomace to water ratio 0.05
0.08 g/mL in a shaking water bath. The authors determined that the extraction time has an important impact on the quality of extracts in terms of content of total phenols and antioxidant activity. Optimal conditions were 30 min, 85 C, and 0.05 g/mL, while the impact of temperature in the 85 C
95 C range was insignificant. In the same study an extraction with methanol was conducted in order to compare the results. It was determined that water extracts produced at optimal conditions have less phenolic compounds and express a lower antioxidant activity than the methanol extracts. However, bearing in mind the toxicity of organic solvents, the authors suggest that using water as a solvent instead of organic solvents demonstrates high feasibility. Water was used as a solvent for the extraction of phenolics from apple pomace in the study by C ¸ am and Aaby (2010). The authors determined that among the five tested process parameters—extraction technique, temperature, extraction time, solvent to solid ratio, and addition of citric acid—it is temperature, extraction time, and solvent to solid ratio that have the most significant impact on the content of total phenols and 5-hydroxymethylfurfural (HMF)—a common product of Maillard reaction. Water extraction under the following conditions: 100 C, 37 min, and 100 mL/g, provides an extract rich in antioxidants with a limited formation of HMF. The obtained optimal extract was compared with extracts obtained by using organic solvents (65% acetone and 80% methanol). Optimal water extraction conditions allowed the obtaining of extracts with lower phenolic content in comparison to the extracts obtained with acetone and methanol. Nevertheless, the authors suggest the superiority of water over organic solvents in terms of availability, health and environmental advantages, and price, especially during large-scale extraction processes. In two of their studies, Wijngaard and Brunton investigated the process of extracting antioxidant compounds from apple pomace. In the first study they applied the response surface methodology and used two food grade solvents, acetone and ethanol, to optimize the antioxidant extraction from industrially generated apple pomace. They concluded that

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TABLE 2.1 Studies of the extraction of antioxidant compounds from apple by-products. Extraction technology

Process parameters

Material

Reference

Maceration

Solvent: ethanol concentration 25%
75% Temperature: 40 C
80 C Extraction time: 20
50 min Solvent: acetone Acetone concentration: 25%
75% Temperature: 40 C
60 C Extraction: 20
60 min Solvent: 70% aqueous acetone Temperature: ambient Solvent: water Extraction treatment: sonification, stirring, shaking, soaking Temperature: 25 C
100 C Extraction time: 10
240 min Solvent/solid ratio: 5
200 mL/g Addition of citric acid: 0.1%
2% Solvent: ethanol Extraction time: 1 h (with stirring) Temperature: 85 C
95 C Extraction time: 15
30 min Material/water ratio: 0.05
0.08 g/mL Shaking in water bath Ethanol concentration: 0%
90% Extraction time: 24 h Solvent: 60% methanol Temperature: ambient Process: mixing (30 s)/centrifugation (14,000 rpm, 3 min, 4 C); extraction repeated four times with supernatant Solvent: ethanol Extraction time: 24 h Solid/solvent ratio: 0.05 g/mL Solvent: ethanol Extraction time: 6 h Material pretreatment: fresh, oven-dried, freeze-dried Solvent: n-hexane Temperature: 60 C Extraction time: 5 h Extraction time: 37 min Solid/solvent ratio: 0.01 g/mL Material pretreatment: fresh, oven-dried, freeze-dried Solvent: 70% ethanol Extraction time: 6 h Irradiation power: 500
700 W Temperature: 40 C
60 C Ethanol concentration: 50
70 Solvent/raw material ratio: 10:1
30:1 Extraction time: 15
35 minEthanol concentration: 40%
80% Irradiation power: 400
800 W Solvent: ethanol, ethyl acetate, and water/methanol mixture Extraction time: 3 3 30 s Irradiation power: 1000 W Solvent: 70% ethanol Extraction time: 1 h Temperature: ambient Temperature: 10 C
40 C Extraction time: 5
55 min Ultrasonic intensity: 0.335
0.764 W/cm3

Pomace

Wijngaard and Brunton (2010)

Pomace

Foo and Lu (1999)

Pomace

C ¸ am and Aaby (2010)

Pomace

Grigoras et al. (2013)

Pomace

Candrawinata et al. (2015)

Herbal dust

Naffati et al. (2017a)

Skin

Arnous and Meyer (2008)

Pomace

Adil et al. (2007)

Pomace

Ferrentino et al. (2018)

Seed

Walia et al. (2014)

Pomace

Ferrentino et al. (2018)

Pomace

Bai et al. (2010)

Pomace

Bai et al. (2010)

Herbal dust

Pavli´c et al. (2016)

Pomace

Grigoras et al. (2013)

Pomace

Bai et al. (2010)

Pomace

Pingret et al. (2012)

Maceration Maceration

Maceration Maceration

Maceration Maceration

Maceration

Soxhlet extraction

Soxhlet extraction

Boiling water maceration

Reflux extraction Microwave-assisted extraction

Microwave-assisted extraction Microwave-assisted extraction

Ultrasound-assisted extraction Ultrasound-assisted water extraction

(Continued )

33

34

Valorization of Fruit Processing By-products

TABLE 2.1 (Continued) Extraction technology

Process parameters

Material

Reference

Ultrasound-assisted extraction Ultrasound-assisted water extraction

Temperature: 40 C
80 C Extraction time: 40
80 minUltrasonic power: 72
216 W Solvent: ethanol Extraction time: 30 min Temperature: ambient Solvent: acetone:water (70:30) Extraction time: 5 min Temperature: 20 C Temperature: 40 C Pressure: 100 MPa Solvent: ethanol Temperature: 75 C
125 C; 160 C
193 C Pressure: 10.3 MPa Solvent: ethanol 14.64%
85.36% Temperature: 40 C
60 C Pressure: 20
60 MPa Extraction time: 10
40 min Solvent: ethanol: 14%
20% Temperature: 25 C
200 C Extraction time: 3
17 min Temperature: 100 C
200 C Extraction time: 10
30 min Solid/solvent ratio: 1%
8% Temperature: 45 C and 55 C Pressure: 20 and 30 MPa Cosolvent: ethanol (0% and 5%) Material pretreatment: fresh, oven-dried, freeze-dried

Herbal dust

Naffati et al. (2017a)

Pomace

Grigoras et al. (2013)

Pomace

Garcı´a et al. (2009)

Pomace

Grigoras et al. (2013)

Pomace

Wijngaard and Brunton (2009)

Pomace

Adil et al. (2007)

Pomace

Plaza and Turner (2015)

Pomace

Ibrahim et al. (2018)

Pomace

Ferrentino et al. (2018)

Ultrasound-assisted extraction Pressurized liquid extraction Pressurized liquid extraction Subcritical carbon dioxide 1 ethanol extraction Subcritical water extraction Subcritical water extraction Supercritical fluid extraction

both ethanol and acetone would be suitable to replace methanol for a food grade and more environment-friendly solid
liquid extraction of antioxidants (Wijngaard and Brunton, 2010). In their second study, Wijngaard and Brunton (2009) applied pressurized liquid extraction and succeeded in significantly increasing the efficiency of the extraction of bioactive compounds from apple pomace. By using the pressurized liquid extraction (ethanol concentrations 25%
75%; temperature ranges 160 C
193 C and 75 C
125 C) they managed to increase the antioxidant activity of extracts by 2.4 times in comparison to the extracts produced with a classical solid
liquid extraction (Wijngaard and Brunton, 2010). Higher temperatures (200 C) showed an advantage in terms of achieving high antioxidant activity. On the other hand, high temperatures caused the formation of HMF. Hence, the authors recommend using lower temperatures from 75 C to 125 C for the recovery of antioxidants from apple pomace. SWE is an appropriate technique for extracting antioxidant compounds from different raw materials (Kovaˇcevi´c et al., 2018; Vladi´c et al., 2017; Naffati et al., 2017a; Eikani et al., 2007; Shotipruk et al., 2004). It was also applied for recovering polyphenols from apple pomace (Plaza and Turner, 2015; Ibrahim et al., 2018). In several studies focusing on the extraction of antioxidants, it was determined that the application of high temperature results in the production of extracts with stronger antioxidant activity. During the extraction with subcritical water, Maillard and caramelization reactions take place and have the formation of neoantioxidants as a consequence, which are the reason for the stronger antioxidant activity on higher temperatures. HMF and furfural are indicators of the Maillard reaction (Plaza and Turner, 2015). Several studies show that HMF and related compounds induce the genotoxic and mutagenic effect in human cells and promote colon cancer in rats (Zhang et al., 1993). Therefore in studies which use high temperatures (SWE) the minimal formation of these products with a maximal provision of other parameters is an important parameter of process quality. Plaza and Turner (2015) examined the extraction and neoformation of antioxidants from apple by-products during SWE. This study demonstrated the impact of temperature (25 C
200 C) and extraction time (3
17 min) on the extraction of antioxidant compounds from apple by-products from the cider industry. The goal was to find the conditions which provide a maximal extraction of phenols with minimal formation of undesired products of the Maillard and

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caramelization reactions at the same time. The time of the extraction did not show a significant influence on the antioxidant capacity of extracts, whereas temperature had an important effect. With the increase of temperature the efficiency of extraction of components with antioxidant characteristics was significantly improved, hence the extracts obtained at 200 C demonstrated an 11
19 times stronger antioxidant activity compared to the extracts obtained at 112 C. Still, the increase of temperature also accelerated the formation of undesired compounds. Therefore the calculated optimal process conditions in terms of maximal antioxidant activity and minimal formation of compounds from the Maillard and caramelization reactions are 125 C extraction temperature and 3 min extraction time. On the other hand, in a new study where subcritical water was used successfully as an extraction solvent for recovering polyphenols from wet apple pomace, the authors determined that the optimized total phenol content and antioxidant activity of extracts were achieved at 200 C during 30 min of extraction with a 1% solid/solvent ratio (Ibrahim et al., 2018). MAE was applied to produce extracts rich in polyphenols using apple pomace as the source. The authors used the Box
Behnken experimental design to evaluate the impact of microwave power, extraction time, ethanol concentration, and solvent/raw material ratio. The results showed that the microwave power has the most significant impact on the yield of phenols, followed by the ration of solvent/raw material, and extraction time. The most optimal conditions were as follows: microwave power 650.4 W, extraction time 53.7 s, ethanol concentration 62.1%, and ratio solvent/material 22.9:1. Compared to the reflux and UAE, the investigated MAE process proved to be significantly more efficient and provided a higher polyphenol yield with a lower consumption of solvents and shorter time of extraction at the same time (53.7, 1, and 6 h, for MAE, UAE, and reflux extraction, respectively) (Bai et al., 2010). UAE and conventional techniques are used to obtain extracts rich in antioxidants from apple pomace (Pingret et al., 2012). It was determined that UAE achieves a 30% higher content of total phenols after 40 min of extraction. In the same study the authors confirmed these findings by large-scale experiments. In addition, the HPLC analysis determined that there was no degradation of main polyphenols in UAE extracts which is the cause of a stronger antioxidant effect of these extracts. Extraction temperature and extraction time had the most dominant influence so the content of total phenols increased with the increase of values of these parameters. The same effect was recorded with ultrasonic intensity. Grigoras et al. (2013) inspected the potential of apple pomace (four different cultivars) as the source of bioactives that can be used in the food, pharmaceutical, and cosmetic industries for improving the quality of final products. In order to determine the impact of different extraction technologies on the extraction yield and chemical composition of extracts, the authors applied conventional maceration and three modern technologies: MAE, UAE, and pressurized liquid extraction. The HPLC profile of obtained extracts was also investigated and there was no significant difference between the extracts obtained by different extraction techniques. However, it was determined that MAE was the most adequate technology for extraction because it provides the highest yield in the shortest time of extraction. The following investigation phase included the investigation of different solvents used in MAE and it was determined that the MAE with ethanol and ethyl acetate solvent can successfully be applied to obtain extracts rich in phenolic and triterpenic compounds. SFE is an alternative technology with great potential for the extraction of molecules that require high standards in terms of yield without any traces of solvents. The most used fluid for extraction of natural materials is carbon dioxide. Carbon dioxide (CO2) is colorless, odorless, nontoxic, nonflammable, and safe for use, plus it is easily separated from the sample by simple depressurization, thus enabling the provision of a clean extract. Its critical parameters are temperature of 31.1 C and pressure of 7.38 MPa. Low critical temperature makes it suitable even for thermolabile components. Because of all the aforementioned reasons, supercritical CO2 (SC-CO2) imposes itself as a method for obtaining highquality and clean products (Molino et al., 2018; Ferrentino et al., 2018; Reverchon and De Marco, 2006). On the other hand, due to its nonpolar nature, CO2 is not an adequate solvent for extracting polar components of interest from apple pomace. Still, it is possible to modify its polarity and increase the solubility of polar components by adding modifiers or polar solvents such as ethanol, methanol, and acetone (Molino et al., 2018; Castro-Vargas et al., 2010; Liza et al., 2010; Macı´as-Sa´nchez et al., 2008; Reverchon and De Marco, 2006; Ollanketo et al., 2001; Johnson and Morgan, 1997). The choice of the cosolvent, apart from the nature and affinities of the target compounds, depends on the toxicity of the solvent and its impact on the environment. The most commonly used solvent is ethanol because it is generally recognized as a safe solvent according to the Food and Drug Administration classification. Furthermore, its use is widespread in the pharmaceutical and food industry (Molino, et al., 2018; Reverchon and De Marco, 2006). Freeze-dried apple pomace was used as a raw material for the subcritical carbon dioxide extraction with ethanol as a cosolvent (14%
20%) under 20
60 MPa pressure, 40 C
60 C temperature, and 10
40 min extraction time (Adil et al., 2007). By applying the response surface methodology and Box
Behnken experimental design, the authors determined the optimal extraction parameters (54.6
57 MPa; 55.7 C
58.4 C; 20% ethanol and 40 min) considering the

36

Valorization of Fruit Processing By-products

content of total phenols and antioxidant capacity of the obtained extracts. Extracts obtained by a traditional extraction technique (maceration with ethanol) were used for comparison. The content of total phenols and antioxidant activity of extracts obtained by subcritical (CO2 1 ethanol) extraction was lower than that of extracts obtained by maceration. However, the antioxidant activity/total phenols or the antioxidant efficiency were higher than that of the extracts obtained by maceration. This further indicates that subcritical (CO2 1 ethanol) extraction can selectively extract polyphenols in lower yield but more active than the one obtained by maceration. In another study, Ferrentino et al. (2018) applied SC-CO2 extraction for the biorecovery of antioxidants from apple pomace. The extraction conditions were as follows: pressure 20 and 30 MPa, temperatures 45 C and 55 C, ethanol concentrations 0% and 5%. Also for the purpose of determining the efficiency of the SC-CO2 for extraction of antioxidants, conventional techniques including the Soxhlet extraction with ethanol and maceration with boiling water were applied. The impact of pretreatments on the quality of extracts was also investigated, hence fresh, oven-, and freeze-dried samples were used in the extraction. The authors determined that by using freeze-dried samples for the SC-CO2 extraction a significant improvement can be achieved in terms of extraction yield, content of polyphenolics, and antioxidant activity. The obtained values were almost doubled with respect to those obtained from fresh pomace. Using ethanol as a cosolvent, the extraction yield, total phenols, and antioxidant activity continued to grow. It was confirmed that freezedrying is the most adequate treatment because it provides a higher amount of desired compounds and a stronger antioxidant activity of extracts. The conditions which provide extracts of the highest content of phenols and antioxidant activity were the following: 30 Ma, 45 C and 55 C, and with 5% ethanol as a cosolvent. Compared to the conventionally obtained extracts, SC-CO2 achieved a significantly lower yield; however, the antioxidant activity of extracts and the content of phenols were higher than that of extracts acquired by traditional extraction techniques. The authors suggest that more active polyphenols are selectively extracted by SC-CO2, which was confirmed by HPLC-DAD-MS identification. The impact of enzymatic treatment on the extraction yield of phenols was investigated in the study by Zheng et al. (2008). The apple pomace containing polyphenols reacted with pectinase under different conditions (pH, ratio of enzyme to pomace, reaction time, and temperature). Optimal conditions for enzymatic hydrolysis and extraction of polyphenols were: pH 3.6, enzyme/pomace ratio 12%, and 11 h at 37 C. These conditions provide a 28% higher yield of total phenols and around 50% higher yield of flavonoids compared to the control values. Our research group investigated the possibility of the utilization of wild apple by-product/waste obtained during the production of fruit filter tea (Naffati et al., 2017b, 2016; Pavli´c et al., 2016; Hojan et al., 2015; Orozovi´c and Vladi´c, 2015). The possibility of wild apple dust biorefining was observed in an investigation of classical and UAE (Naffati et al., 2016, 2017b). Extracts were obtained by applying maceration at room temperature during a 24-h period and by using different concentrations of ethanol (0%, 30%, 50%, 70%, and 90%). Next, the content of total phenols and flavonoids were investigated. Seventy percent ethanol was determined to be the most suitable solvent for the extraction of polyphenolic compounds from apple dust and it was chose as a solvent for the UAE. Optimization of the UAE was also conducted by applying response surface methodology and varying the process parameters (40 C
80 C; 40
80 min; 72
216 W). UAE proved to be a more efficient method which produced extracts of a much higher concentration of targeted compounds, total phenols, and flavonoids than a classical extraction. It was determined that temperature and time of interaction were the most dominant and highly important factors for the extraction of total phenolics. In the case of total phenols extraction with the application of high temperature, the degradation of certain heat-sensitive phenolic constituents of wild apple dust could occur, thus the optimal temperature for the extraction of phenols was 69.2 C. In addition, the application of higher ultrasound power for a longer time period could lead to the degradation of certain flavonoids constituents, so the optimal ultrasonic power for flavonoid extraction was 75.6 W. The results obtained in this study emphasized the significant potential of wild apple dust as a raw material for the extraction of antioxidant compounds. The results demonstrate the high potential for the utilization of wild apple fruit dust in terms of extraction and production of extracts with a high concentration of phenolic constituents. In other studies (Pavli´c et al., 2016; Hojan et al., 2015), the authors applied MAE to successfully recover polyphenolic antioxidants from wild apple dust generated in the filter tea industry. The studies investigated the influence of extraction time (15
35 min), ethanol concentration (40%
80%), and irradiation power (400
800 W) on extraction yield, total phenols content, total flavonoids content, and antioxidant activity parameters. It was determined that maximization of polyphenols yield and antioxidant activity did not demand high energy consumption as an optimal condition for the energy parameter—extraction time and irradiation power were approximately 15 min and 400
464 W. Although MAE was recommended as an efficient technique for extraction of antioxidant compounds from apple dust, from a comparison of the quality of extracts obtained with UAE (Naffati et al., 2017b) and MAE (Pavli´c et al., 2016), it can be concluded that the UAE is a more favorable technique. Using UAE secures the production of apple dust extracts with better quality in terms of total content of phenols, flavonoids, and antioxidant capacity.

Apple Chapter | 2

37

Also the possibility of valorization of apple dust generated in the filter tea was investigated by using a combination of extracting and drying technology (Orozovi´c and Vladi´c, 2015). Using a 50% ethanol as a solvent, UAE was applied for the purposes of obtaining a liquid extract which was transformed into a powder form by applying the spray drying technology. The obtained powder was of adequate quality with respect to physicochemical characteristics. Furthermore, a fast reconstruction into liquid form with the addition of a solvent emphasized the feasibility of this type of production process, bearing in mind that dry extracts have numerous advantages over liquid ones. The advantages are smaller volume, extended stability, easier manipulation, storage, and transport (Vidovi´c et al., 2014). Apart from exploiting the primary-generated apple pomace waste, the possibility of valorization of apple skin, which is generated as a secondary waste/by-product, was also investigated. Arnous and Meyer (2008) conducted a study on exploiting apple skin. Moreover, with the extraction with 60% methanol, they determined that apple skin is an important source of catechin. Seed separated from apple pomace was used in a study by Walia et al. (2014) for the extraction of oil. The fatty acid composition, physicochemical, antioxidant, and anticancer properties of the obtained oil were explored. It was concluded that the physicochemical properties of seed oil were comparable with edible food oil, indicating its better stability and broad application in the food and pharmaceutical industries. The authors also suggested that the oil is a valuable source of antioxidant compounds, and it demonstrated in vitro cytotoxic activity against specific cell lines. The aforementioned studies had found an efficient solution for extracting antioxidant compounds. However, bearing in mind that polyphenols and pectin are present in the apple pomace, Schieber et al. (2003) did a study on the simultaneous extraction of both pectin and polyphenols from apple pomace. The authors used food grade hydrophobic styrenedivinylbenzene copolymerizate for separating polyphenols compounds from pectin in acidic dried pomace. Once elution with methanol was completed, the polyphenolics were concentrated under vacuum and stabilized by lyophilization. The dominant compounds were phloridzin, chlorogenic acid, and quercetin glycosides. Decolorization of the pectin extract occurred as a result of the removal of oxidized phenolic compounds (Schieber et al., 2003). Simultaneous extraction of both types of valuable compounds is possible. Additional research in the field of separation technology is required for the purification of these valuable compounds (Perussello et al., 2017).

2.4

Conclusion

Bearing in mind all the information presented above it can be concluded, that as the apple is one of the most produced, processed, and consumed fruits worldwide, the generation of various apple by-products continue. Considering the chemical composition (10%
15% of pectin, the high concentration of carbohydrates, the crude fibers, and minerals, as well as the presence of important and various phenolic constituents) and the quantity of production, apple pomace has the highest potential for further applications. Apple pomace has been traditionally used as an animal feed and as fertilizer. Nowadays its use for pectin production is the dominant application of this kind of by-product. But owing to the high carbohydrate content there is a high potential for apple pomace to be applied as a quality substrate in a number of microbial processes for the production of various value-added products, such as ethanol and organic acids. In addition, new innovative solutions considering apple pomace and other apple by-products applications should be expected, especially in the fields of the development and production of new extracts and functional products (such as biscuits and other products of the bakery industry).

References Adetunji, L.R., Adekunle, A., Orsat, V., Raghavan, V., 2017. Advances in the pectin production process using novel extraction techniques: A review. Food Hydrocol 62, 239
250. Adil, I.H., Cetin, H.I., Yener, M.E., Bayındırlı, A., 2007. Subcritical (carbon dioxide 1 ethanol) extraction of polyphenols from apple and peach pomaces, and determination of the antioxidant activities of the extracts. J. Supercrit. Fluids 43 (1), 55
63. Arnous, A., Meyer, A.S., 2008. Comparison of methods for compositional characterization of grape (Vitis vinifera L.) and apple (Malus domestica) skins. Food Bioprod. Process. 86 (2), 79
86. Ashurst, P., Hargitt, R., Palmer, F., 2017. Soft Drink and Fruit Juice Problems Solved. Woodhead Publishing. Bai, X.L., Yue, T.L., Yuan, Y.H., Zhang, H.W., 2010. Optimization of microwave-assisted extraction of polyphenols from apple pomace using response surface methodology and HPLC analysis. J. Sep. Sci. 33 (23
24), 3751
3758. Barrett, D.M., Somogyi, L., Ramaswamy, H.S., 2004. Processing Fruits: Science and Technology. CRC Press. Bartkiene, E., Vizbickiene, D., Bartkevics, V., Pugajeva, I., Krungleviciute, V., Zadeike, D., et al., 2017. Application of Pediococcus acidilactici LUHS29 immobilized in apple pomace matrix for high value wheat-barley sourdough bread. LWT-Food Sci. Technol. 83, 157
164.

38

Valorization of Fruit Processing By-products

Bhalla, T.C., Joshi, M., 1994. Protein enrichment of apple pomace by co-culture of cellulolytic moulds and yeasts. World J. Microbiol. Biotechnol. 10 (1), 116
117. Bhushan, S., Kalia, K., Sharma, M., Singh, B., Ahuja, P.S., 2008. Processing of apple pomace for bioactive molecules. Crit. Rev. Biotechnol. 28 (4), 285
296. Bolarinwa, I.F., Orfila, C., Morgan, M.R., 2015. Determination of amygdalin in apple seeds, fresh apples and processed apple juices. Food Chem. 170, 437
442. Boyer, J., Liu, R.H., 2004. Apple phytochemicals and their health benefits. Nutr. J. 3 (1), 5. Brajanoski, B., Brajanoski, D., 2004. New technologies in clear apple juice concentrate processing. J. Process. Energy Agric. PTEP 8 (3
4), 87
89. Burda, S., Oleszek, W., Lee, C.Y., 1990. Phenolic compounds and their changes in apples during maturation and cold storage. J. Agric. Food Chem. 38 (4), 945
948. C ¸ am, M., Aaby, K., 2010. Optimization of extraction of apple pomace phenolics with water by response surface methodology. J. Agric. Food Chem. 58 (16), 9103
9111. Campanella, L., Bonanni, A., Tomassetti, M., 2003. Determination of the antioxidant capacity of samples of different types of tea, or of beverages based on tea or other herbal products, using a superoxide dismutase biosensor. J. Pharmaceut. Biomed. Anal. 32 (4
5), 725
736. Candrawinata, V.I., Golding, J.B., Roach, P.D., Stathopoulos, C.E., 2015. Optimisation of the phenolic content and antioxidant activity of apple pomace aqueous extracts. CyTA-J. Food 13 (2), 293
299. Canteri-Schemin, M.H., Fertonani, H.C.R., Waszczynskyj, N., Wosiacki, G., 2005. Extraction of pectin from apple pomace. Braz. Arch. Biol. Technol. 48 (2), 259
266. Castro-Vargas, H.I., Rodrı´guez-Varela, L.I., Ferreira, S.R., Parada-Alfonso, F., 2010. Extraction of phenolic fraction from guava seeds (Psidium guajava L.) using supercritical carbon dioxide and co-solvents. J. Supercrit. Fluids 51 (3), 319
324. ˇ Cetkovi´c, G., Canadanovi´ c-Brunet, J., Djilas, S., Savatovi´c, S., Mandi´c, A., Tumbas, V., 2008. Assessment of polyphenolic content and in vitro antiradical characteristics of apple pomace. Food Chem. 109 (2), 340
347. Cohen, E., Birk, Y., Mannheim, C.H., Saguy, I.S., 1998. A rapid method to monitor quality of apple juice during thermal processing. LWT-Food Sci. Technol. 31 (7
8), 612
616. Council Directive, 2012. Council Directive 2012/12/EU of the European Parliament and of the Council of 19 April 2012 amending Council Directive 2001/112/EC relating to fruit juices and certain similar products intended for human consumption. Dhillon, G.S., Kaur, S., Brar, S.K., 2013a. Perspective of apple processing wastes as low-cost substrates for bioproduction of high value products: a review. Renew. Sustain. Energy Rev. 27, 789
805. Dhillon, G.S., Kaur, S., Sarma, S.J., Brar, S.K., 2013b. Integrated process for fungal citric acid fermentation using apple processing wastes and sequential extraction of chitosan from waste stream. Ind. Crops Prod. 50, 346
351. Dixon, J., 1999. Enhancement of Aroma and Flavour Volatiles in Apple Juice: A Thesis Presented in Partial Fulfilment of the Requirements for the Degree of Doctor of Philosophy in Plant Physiology at Massey University (Doctoral dissertation). Massey University. Eikani, M.H., Golmohammad, F., Rowshanzamir, S., 2007. ). Subcritical water extraction of essential oils from coriander seeds (Coriandrum sativum L.). J. Food Eng. 80 (2), 735
740. Endress, H.U., 2000. High quality resulting from product integrated environment protection (PIUS). Fruit Process. 10 (7), 273
277. Escarpa, A., Gonza´lez, M.C., 1998. High-performance liquid chromatography with diode-array detection for the determination of phenolic compounds in peel and pulp from different apple varieties. J. Chromatogr. A 823 (1
2), 331
337. Evcan, E., Tari, C., 2015. Production of bioethanol from apple pomace by using cocultures: conversion of agro-industrial waste to value added product. Energy 88, 775
782. FAOSTAT Production Database, 2013. http://www.fao.org/news/archive/news-by-date/2013/en/. FAOSTAT Production Database, 2016. ,http://faostat.fao.org. (accessed 15.03.16.). Ferrentino, G., Morozova, K., Mosibo, O.K., Ramezani, M., Scampicchio, M., 2018. Biorecovery of antioxidants from apple pomace by supercritical fluid extraction. J. Cleaner Prod. 186, 253
261. Foo, L.Y., Lu, Y., 1999. Isolation and identification of procyanidins in apple pomace. Food Chem. 64 (4), 511
518. Fromm, M., Bayha, S., Carle, R., Kammerer, D.R., 2012. Comparison of fatty acid profiles and contents of seed oils recovered from dessert and cider apples and further Rosaceous plants. Eur. Food Res. Technol. 234 (6), 1033
1041. Fu, C., Tian, H., Li, Q., Cai, T., Du, W., 2006. Ultrasound-assisted extraction of xyloglucan from apple pomace. Ultrason. Sonochem. 13 (6), 511
516. Garcı´a, Y.D., Valles, B.S., Lobo, A.P., 2009. Phenolic and antioxidant composition of by-products from the cider industry: apple pomace. Food Chem. 117 (4), 731
738. Girard, B., Fukumoto, L.R., 1999. Apple juice clarification using microfiltration and ultrafiltration polymeric membranes. LWT-Food Sci. Technol. 32 (5), 290
298. Golding, J., 2012. Monitoring Natural Phenolics and Antioxidants in Processing Apple Juice. NSW Department of Primary Industries. Golding, J.B., McGlasson, W.B., Wyllie, S.G., Leach, D.N., 2001. Fate of apple peel phenolics during cool storage. J. Agric. Food Chem. 49 (5), 2283
2289. Go´rna´s, P., Rudzi´nska, M., Segli¸na, D., 2014. Lipophilic composition of eleven apple seed oils: a promising source of unconventional oil from industry by-products. Ind. Crops Prod. 60, 86
91. Grigoras, C.G., Destandau, E., Fouge`re, L., Elfakir, C., 2013. Evaluation of apple pomace extracts as a source of bioactive compounds. Ind. Crops Prod. 49, 794
804.

Apple Chapter | 2

39

Gunko, S., Verbych, S., Bryk, M., Hilal, N., 2006. Concentration of apple juice using direct contact membrane distillation. Desalination 190 (1
3), 117
124. Gutzwiller, A., Czegledi, L., Stoll, P., Bruckner, L., 2007. Effects of Fusarium toxins on growth, humoral immune response and internal organs in weaner pigs, and the efficacy of apple pomace as an antidote. J. Anim. Physiol. Anim. Nutr. 91 (9
10), 432
438. Gvozdenovi´c, D., Vraˇcar, L., Tepi´c, A., 2006. Harvest, storing and technology of fruit processing. J. Pomol. 40 (155), 237
244. Hojan, T., Naffati, A., Pavli´c, B., Vladi´c, J., 2015. Optimization of microwave extraction byproduct of wild apples (Malus sylvestris). In: Third Conference of Young Chemist of Serbia, Belgrade, Serbia, Book of Abstracts, p. 7. Horva´th-Kerkai, E., 2006. Manufacturing fruit beverages. Handbook of Fruits and Fruit Processing. Blackwell Publishing, p. 205. Ibrahim, S., Santos, R., Bowra, S., 2018. Optimization of subcritical water mediated extraction of apple pomace polyphenolics and their antioxidant activity. J. Chromatogr. Sep. Tech. 9 (410), 2. Johnson, S., Morgan, E.D., 1997. Supercritical fluid extraction of oil and triterpenoids from neem seeds. Phytochem. Anal. Int. J. Plant Chem. Biochem. Tech. 8 (5), 228
232. Jongen, W. (Ed.), 2002. Fruit and Vegetable Processing: Improving Quality. Elsevier. Joshi, V.K., Gupta, K., Devrajan, A., Lal, B.B., Arya, S.P., 2000. Production and evaluation of fermented apple pomace in the feed of broilers. J. Food Sci. Technol. (Mysore) 37 (6), 609
612. Jozunovi´c, A., 2015. Properties of Corn Snack Products Enriched With Food Industry By-products (PhD thesis). Josip Juraj Strossmayer University of Osijek, Faculty of Food Technology Osijek. Ju, Z., Yuan, Y., Liu, C., Zhan, S., Wang, M., 1996. Relationships among simple phenol, flavonoid and anthocyanin in apple fruit peel at harvest and scald susceptibility. Postharvest Biol. Technol. 8 (2), 83
93. Kammerer, D.R., Kammerer, J., Valet, R., Carle, R., 2014. Recovery of polyphenols from the by-products of plant food processing and application as valuable food ingredients. Food Res. Int. 65, 2
12. Kovaˇcevi´c, D.B., Barba, F.J., Granato, D., Galanakis, C.M., Herceg, Z., Dragovi´c-Uzelac, V., et al., 2018. Pressurized hot water extraction (PHWE) for the green recovery of bioactive compounds and steviol glycosides from Stevia rebaudiana Bertoni leaves. Food Chem. 254, 150
157. Kujawski, W., Sobolewska, A., Jarzynka, K., Gu¨ell, C., Ferrando, M., Warczok, J., 2013. Application of osmotic membrane distillation process in red grape juice concentration. J. Food Eng. 116 (4), 801
808. Kumar, A., Chauhan, G.S., 2010. Extraction and characterization of pectin from apple pomace and its evaluation as lipase (steapsin) inhibitor. Carbohydr. Polym. 82 (2), 454
459. Liza, M.S., Rahman, R.A., Mandana, B., Jinap, S., Rahmat, A., Zaidul, I.S.M., et al., 2010. Supercritical carbon dioxide extraction of bioactive flavonoid from Strobilanthes crispus (Pecah Kaca). Food Bioprod. Process. 88 (2
3), 319
326. Lozano, J.E., 2006. Fruit Manufacturing. Springer Science 1 Business Media, LLC. Lu, Y., Foo, L.Y., 1997. Identification and quantification of major polyphenols in apple pomace. Food Chem. 59 (2), 187
194. Lu, Y., Foo, L.Y., 1998. Constitution of some chemical components of apple seed. Food Chem. 61 (1
2), 29
33. Lu, Y., Foo, L.Y., 2000. Antioxidant and radical scavenging activities of polyphenols from apple pomace. Food Chem. 68 (1), 81
85. Mahawar, M., Singh, A., Jalgaonkar, K., 2012. Utility of apple pomace as a substrate for various products: A review. Food Bioprod. Process. 90 (4), 597
605. Mao, H., Zhang, T., Li, R., Zhai, B., Wang, Z., Wang, Q., et al., 2017. Apple pomace improves the quality of pig manure aerobic compost by reducing emissions of NH3 and N2O. Sci. Rep. 7 (1), 870. Mari´c, M., Grassino, A.N., Zhu, Z., Barba, F.J., Brnˇci´c, M., Brnˇci´c, S.R., 2018. An overview of the traditional and innovative approaches for pectin extraction from plant food wastes and by-products: ultrasound-, microwaves-, and enzyme-assisted extraction. Trends Food Sci. Technol. 76, 28
37. Macı´as-Sa´nchez, M.D., Mantell Serrano, C., Rodrı´guez Rodrı´guez, M., Martı´nez de la Ossa, E., Lubia´n, L.M., Montero, O., 2008. Extraction of carotenoids and chlorophyll from microalgae with supercritical carbon dioxide and ethanol as cosolvent. J. Sep. Sci. 31 (8), 1352
1362. Maslovari´c, M., 2017. A Study on the Nutritive Value of Dried Apple Pomace and Possibilities for Using Its Utilization in the Industrial Production of Animal Feed (PhD thesis). University of Novi Sad, Faculty of Technology Novi Sad. ˇ Maslovari´c, M.D., Vukmirovi´c, Ð., Pezo, L., Colovi´ c, R., Jovanovi´c, R., Spasevski, N., et al., 2017. Influence of apple pomace inclusion on the process of animal feed pelleting. Food Addit. Contam. A 34 (8), 1353
1363. Massias, A., Boisard, S., Baccaunaud, M., Calderon, F.L., Subra-Paternault, P., 2015. Recovery of phenolics from apple peels using CO21 ethanol extraction: kinetics and antioxidant activity of extracts. J. Supercrit. Fluids 98, 172
182. Mazza, G., Velioglu, Y.S., 1992. Anthocyanins and other phenolic compounds in fruits of red-flesh apples. Food Chem. 43 (2), 113
117. McRae, K.B., Lidster, P.D., Demarco, A.C., Dick, A.J., 1990. Comparison of the polyphenol profiles of apple fruit cultivars by correspondence analysis. J. Sci. Food Agric. 50 (3), 329
342. Mir, S.A., Bosco, S.J.D., Shah, M.A., Santhalakshmy, S., Mir, M.M., 2017. Effect of apple pomace on quality characteristics of brown rice based cracker. J. Saudi Soc. Agric. Sci. 16 (1), 25
32. Molino, A., Mehariya, S., Iovine, A., Larocca, V., Di Sanzo, G., Martino, M., et al., 2018. Extraction of astaxanthin and lutein from microalga Haematococcus pluvialis in the red phase using CO2 supercritical fluid extraction technology with ethanol as co-solvent. Marine Drugs 16 (11), 432. Naffati, A., Vladi´c, J., Pavli´c, B., Blagojevi´c, M., Vidovi´c, S., 2016. Bio-refining of filter tea factory by-products: classical and ultrasound assisted extraction of bioactive compounds from wild apple dust. In: The International BioScience Conference and 6th International PSU-UNS Bioscience Conference, Novi Sad, Serbia, Book of Abstracts, pp. 333
334. Naffati, A., Vladi´c, J., Pavli´c, B., Vidovi´c, S., 2017a. Biorefining of filter tea factory by-products: classical and ultrasound-assisted extraction of bioactive compounds from wild apple fruit dust. J. Food Process Eng. 40 (6), e12572.

40

Valorization of Fruit Processing By-products

Naffati, A., Vladi´c, J., Pavli´c, B., Radosavljevi´c, R., Gavari´c, A., Vidovi´c, S., 2017b. Recycling of filter tea industry by-products: application of subcritical water extraction for recovery of bioactive compounds from A. uva-ursi herbal dust. J. Supercrit. Fluids 121, 1
9. Niketi´c-Aleksi´c, G., 1988. Technology of Fruit and Vegetables. Faculty of Agriculture, Belgrade. Oleszek, W., Lee, C.Y., Jaworski, A.W., Price, K.R., 1988. Identification of some phenolic compounds in apples. J. Agric. Food Chem. 36 (3), 430
432. Ollanketo, M., Hartonen, K., Riekkola, M.L., Holm, Y., Hiltunen, R., 2001. Supercritical carbon dioxide extraction of lycopene in tomato skins. Eur. Food Res. Technol. 212 (5), 561
565. Oreopoulou, V., Tzia, C., 2007. Utilization of plant by-products for the recovery of proteins, dietary fibers, antioxidants, and colorants. Utilization of By-Products and Treatment of Waste in the Food Industry. Springer, Boston, MA, pp. 209
232. Orozovi´c, M., Vladi´c, J., 2015. Production of dry extract of wild apple (Malus sylvetris) using spray drying techniques. In: Third Conference of Young Chemist of Serbia, Belgrade, Serbia, Book of Abstracts, p. 103. O’Shea, N., Arendt, E.K., Gallagher, E., 2012. Dietary fiber and phytochemical characteristics of fruit and vegetable by-products and their recent applications as novel ingredients in food products. Innov. Food Sci. Emerg. Technol. 16, 1
10. O’Shea, N., Ktenioudaki, A., Smyth, T.P., McLoughlin, P., Doran, L., Auty, M.A.E., et al., 2015. Physicochemical assessment of two fruit byproducts as functional ingredients: apple and orange pomace. J. Food Eng. 153, 89
95. Pavli´c, B., Vidovi´c, S., Vladi´c, J., Radosavljevi´c, R., Cindri´c, M., Zekovi´c, Z., 2016. Subcritical water extraction of sage (Salvia officinalis L.) by-products—Process optimization by response surface methodology. J Supercrit. Fluid. 116, 36
45. ¨ pfeln Pe´rez-Ilzarbe, J., Herna´ndez, T., Estrella, I., 1991. Phenolic compounds in apples: varietal differences [Phenolische Verbindungen in A Unterschiede zwischen verschiedenen Apfelsorten]. Z. Lebensm. Unters. Forsch. 192 (6), 551
554. Perussello, C.A., Zhang, Z., Marzocchella, A., Tiwari, B.K., 2017. Valorization of apple pomace by extraction of valuable compounds. Comprehen. Rev. Food Sci. Food Saf. 16 (5), 776
796. Petkovsek, M.M., Stampar, F., Veberic, R., 2007. ). Parameters of inner quality of the apple scab resistant and susceptible apple cultivars (Malus domestica Borkh.). Sci. Horticult. 114 (1), 37
44. Petrovi´c, J., 2018. Valorization of the Nutritional Profile of Cookies Produced With the Addition of Food Industry By-products (PhD thesis). University of Novi Sad, Faculty of Technology Novi Sad. Pieszka, M., Szczurek, P., Bederska-Łojewska, D., Migdał, W., Pieszka, M., Gogol, P., et al., 2017. The effect of dietary supplementation with dried fruit and vegetable pomaces on production parameters and meat quality in fattening pigs. Meat Sci. 126, 1
10. Pingret, D., Fabiano-Tixier, A.S., Le Bourvellec, C., Renard, C.M., Chemat, F., 2012. Lab and pilot-scale ultrasound-assisted water extraction of polyphenols from apple pomace. J. Food Eng. 111 (1), 73
81. Plaza, M., Turner, C., 2015. Pressurized hot water extraction of bioactives. TrAC-Trend Anal. Chem. 71, 39
54. Rabetafika, H.N., Bchir, B., Blecker, C., Richel, A., 2014. Fractionation of apple by-products as source of new ingredients: current situation and perspectives. Trends Food Sci. Technol. 40 (1), 99
114. Rajauria, G., Tiwari, B.K. (Eds.), 2017. Fruit Juices: Extraction, Composition, Quality and Analysis. Academic Press. Rana, S., Gupta, S., Rana, A., Bhushan, S., 2015. Functional properties, phenolic constituents and antioxidant potential of industrial apple pomace for utilization as active food ingredient. Food Sci. Hum. Wellness 4 (4), 180
187. Reverchon, E., De Marco, I., 2006. Supercritical fluid extraction and fractionation of natural matter. J. Supercrit. Fluids 38 (2), 146
166. Roth, E., Berna, A., Beullens, K., Yarramraju, S., Lammertyna, J., Schenk, A., et al., 2007. Postharvest quality of integrated and organically produced apple fruit. Postharvest Biol. Technol. 45, 11
19. Rust, S., Buskirk, D., 2008. Feeding apples or apple pomace in cattle diets. Cattle Call 13 (4), 2
3. Sa´nchez-Rabaneda, F., Jauregui, O., Lamuela-Ravento´s, R.M., Viladomat, F., Bastida, J., Codina, C., 2004. Qualitative analysis of phenolic compounds in apple pomace using liquid chromatography coupled to mass spectrometry in tandem mode. Rapid Commun. Mass Spectromet. 18 (5), 553
563. Sandhu, K.S., Minhas, K.S., 2006. Oranges and citrus juices. Handbook of Fruits and Fruit Processing. Blackwell Publishing, vol. 60, p. 309. Schieber, A., Keller, P., Carle, R., 2001. Determination of phenolic acids and flavonoids of apple and pear by high-performance liquid chromatography. J. Chromatogr. A 910 (2), 265
273. Schieber, A., Hilt, P., Streker, P., Endreß, H.U., Rentschler, C., Carle, R., 2003. A new process for the combined recovery of pectin and phenolic compounds from apple pomace. Innov. Food Sci. Emerg. Technol. 4 (1), 99
107. Schobinger, U., 2001. Frucht- und Gemu¨sesa¨fte. Handbuch der Lebensmitteltechnologie. Verlag Ulmer, Stuttgart, 3. Aufl. Shalini, R., Gupta, D.K., 2010. Utilization of pomace from apple processing industries: a review. J. Food Sci. Technol. 47 (4), 365
371. Shin, H.H., Kim, C.T., Cho, Y.J., Hwang, J.K., 2005. Analysis of extruded pectin extraction from apple pomace by response surface methodology. Food Sci. Biotechnol. 14 (1), 28
31. Shotipruk, A., Kiatsongserm, J., Pavasant, P., Goto, M., Sasaki, M., 2004. Pressurized hot water extraction of anthraquinones from the roots of Morinda citrifolia. Biotechnol. Prog. 20 (6), 1872
1875. Sinha, N., Sidhu, J., Barta, J., Wu, J., Cano, M.P. (Eds.), 2012. Handbook of Fruits and Fruit Processing. John Wiley & Sons. Soares, M.C.R., Kuskoski, E.M., Gonzaga, L.V., Lima, A., Mancini Filho, J., 2008. Composition of phenolic acids content in apple (Malus sp.) pomace. Semin. Cieˆnc. Agra´r. 29 (2), 339
348. Spanos, G.A., Wrolstad, R.E., 1992. Phenolics of apple, pear, and white grape juices and their changes with processing and storage. A review. J. Agric. Food Chem. 40 (9), 1478
1487. Su, S.K., Wiley, R.C., 1998. Changes in apple juice flavor compounds during processing. J. Food Sci. 63 (4), 688
691. ´ lvarez, A ´ .L., Garcı´a, Y.D., del Barrio, G., Lobo, A.P., Parra, F., 2010. Phenolic profiles, antioxidant activity and in vitro antiviral properSua´rez, B., A ties of apple pomace. Food Chem. 120 (1), 339
342.

Apple Chapter | 2

41

Sudha, M.L., Baskaran, V., Leelavathi, K., 2007. Apple pomace as a source of dietary fiber and polyphenols and its effect on the rheological characteristics and cake making. Food Chem. 104 (2), 686
692. ˇ Sulc, D., 1969. Poznavanje sirovina, pomoˇsnih sirovina i pomoˇsnog materijala za proizvodnju preraðevina vo´ca i povr´ca. Tehnoloˇski fakultet, Univerzitet Novi Sad. Sulc, D., Vereˇsbaranji, I., Navaluˇsi´c, J., Markovi´c, B., Pe´co, N., 1985. Ispitivanja u cilju razrade tehnoloˇskog postupka za proizvodnju pektina iz suncokreta. Tehnoloˇski fakultet, Univerzitet Novi Sad. Sundarraj, A.A., Vasudevan, R.T., Sriramulu, G., 2018. Optimized extraction and characterization of pectin from jackfruit (Artocarpus integer) wastes using response surface methodology. Int. J. Biol. Macromol. 106, 698
703. ˇ Tepi´c, A., Sumi´ c, Z., Irˇsevi´c, R., 2011. The possibility of utilisation of apple pomace in jelly production. In: XVI Savetovanje o biotehnologiji sa ˇ cak, Serbia, 16, 18 2011. pp. 557
562. meðunarodnim uˇceˇsc´ em, Caˇ Tsao, R., Yang, R., Young, J.C., Zhu, H., 2003. Polyphenolic profiles in eight apple cultivars using high-performance liquid chromatography (HPLC). J. Agric. Food Chem. 51 (21), 6347
6353. Ucuncu, C., Tari, C., Demir, H., Buyukkileci, A.O., Ozen, B., 2013. Dilute-acid hydrolysis of apple, orange, apricot and peach pomaces as potential candidates for bioethanol production. J. Biobased Mater. Bioenergy 7 (3), 376
389. van der Sluis, A.A., Dekker, M., de Jager, A., Jongen, W.M., 2001. Activity and concentration of polyphenolic antioxidants in apple: effect of cultivar, harvest year, and storage conditions. J. Agric. Food Chem. 49 (8), 3606
3613. Vasantha Rupasinghe, H.P., Wang, L., Pitts, N.L., Astatkie, T., 2009. Baking and sensory characteristics of muffins incorporated with apple skin powder. J. Food Qual. 32 (6), 685
694. Vasilisin, L., Grubaˇci´c, M., 2003. The influence of different methods of clarification on the quality of concentrated apple juice. J. Pomol. 163
167. Vendruscolo, F., Albuquerque, P.M., Streit, F., Esposito, E., Ninow, J.L., 2008. Apple pomace: a versatile substrate for biotechnological applications. Crit. Rev. Biotechnol. 28 (1), 1
12. Vidovi´c, S., Cvetkovic, D., Rami´c, M., Dunji´c, M., Malbaˇsa, R., Tepi´c, A., et al., 2013. Screening of changes in content of health benefit compounds, antioxidant activity and microbiological status of medicinal plants during the production of herbal filter tea. Ind. Crops Prod. 50, 338
345. ˇ Vidovi´c, S.S., Vladi´c, J.Z., Vaˇstag, Z.G., Zekovi´c, Z.P., Popovi´c, L.M., 2014. Maltodextrin as a carrier of health benefit compounds in Satureja montana dry powder extract obtained by spray drying technique. Powder Technol. 258, 209
215. Vieira, F.G.K., Borges, G.D.S.C., Copetti, C., Amboni, R.D.D.M.C., Denardi, F., Fett, R., 2009. Physico-chemical and antioxidant properties of six apple cultivars (Malus domestica Borkh) grown in southern Brazil. Sci. Horticult. 122 (3), 421
425. Villas-Boˆas, S.G., Esposito, E., de Mendonca, M.M., 2003. Bioconversion of apple pomace into a nutritionally enriched substrate by Candida utilis and Pleurotus ostreatus. World J. Microbiol. Biotechnol. 19 (5), 461
467. Visioli, F., Borsani, L., Galli, C., 2000. Diet and prevention of coronary heart disease: the potential role of phytochemicals. Cardiovasc. Res. 47 (3), 419
425. Vladi´c, J., Canli, O., Pavli´c, B., Zekovi´c, Z., Vidovi´c, S., Kaplan, M., 2017. Optimization of Satureja montana subcritical water extraction process and chemical characterization of volatile fraction of extracts. J. Supercrit. Fluids 120, 86
94. Vujiˇci´c, B., 1975. Isolation of Pectolytic Preparation From Tomato and Examination of its Efficiency on Model Substances and Fruit and Vegetables (PhD thesis). University of Novi Sad, Faculty of Technology Novi Sad. Vukosavljevi´c, P., 2008. Clarification and Concentration of Fruit Juices Using Membrane Separation Processes. Andrejevi´c Endowment, Belgrade. Waldbauer, K., McKinnon, R., Kopp, B., 2017. Apple pomace as potential source of natural active compounds. Planta Med. 83 (12/13), 994
1010. Walia, M., Rawat, K., Bhushan, S., Padwad, Y.S., Singh, B., 2014. Fatty acid composition, physicochemical properties, antioxidant and cytotoxic activity of apple seed oil obtained from apple pomace. J. Sci. Food Agric. 94 (5), 929
934. Wang, H.J., Thomas, R.L., 1989. Direct use of apple pomace in bakery products. J. Food Sci. 54 (3), 618
620. Wang, S., Chen, F., Wu, J., Wang, Z., Liao, X., Hu, X., 2007. Optimization of pectin extraction assisted by microwave from apple pomace using response surface methodology. J. Food Eng. 78 (2), 693
700. Wang, X., Chen, Q., Lu¨, X., 2014. Pectin extracted from apple pomace and citrus peel by subcritical water. Food Hydrocolloid. 38, 129
137. Wang, N., Wolf, J., Yhang, F., 2016. Towards sustainable intensification of apple production in China-Yield gaps and nutrient use efficiency in apple farming systems. J. Integr. Agric. 15 (4), 716
725. Wijngaard, H., Brunton, N., 2009. The optimization of extraction of antioxidants from apple pomace by pressurized liquids. J. Agric. Food Chem. 57 (22), 10625
10631. Wijngaard, H.H., Brunton, N., 2010. The optimisation of solid
liquid extraction of antioxidants from apple pomace by response surface methodology. J. Food Eng. 96 (1), 134
140. Wikiera, A., Mika, M., Grabacka, M., 2015a. Multicatalytic enzyme preparations as effective alternative to acid in pectin extraction. Food Hydrocolloid. 44, 156
161. Wolfe, K.L., Liu, R.H., 2003. Apple peels as a value-added food ingredient. J. Agric. Food Chem. 51 (6), 1676
1683. Yu, X., van de Voort, F.R., Li, Z., Yue, T., 2007. Proximate composition of the apple seed and characterization of its oil. Int. J. Food Eng. 3 (5). Available from: http://dx.doi.org/10.2202/1556-3758.1283. Zambra, C., Romero, J., Pino, L., Saavedra, A., Sanchez, J., 2015. Concentration of cranberry juice by osmotic distillation process. J. Food Eng. 144, 58
65. Zhang, X.M., Chan, C.C., Stamp, D., Minkin, S., Archer, C.M., Bruce, W.R., 1993. Initiation and promotion of colonic aberrant crypt foci in rats by 5-hydroxymethy1-2-furaldehyde in thermolyzed sucrose. Carcinogenesis 14 (4), 773
775. Zhang, H., Woodams, E.E., Hang, Y.D., 2011. Influence of pectinase treatment on fruit spirits from apple mash, juice and pomace. Process Biochem. 46 (10), 1909
1913.

42

Valorization of Fruit Processing By-products

Zhang, L., Ye, X., Ding, T., Sun, X., Xu, Y., Liu, D., 2013. Ultrasound effects on the degradation kinetics, structure and rheological properties of apple pectin. Ultrason. Sonochem. 20 (1), 222
231. Zheng, H.Z., Lee, H.R., Lee, S.H., Kim, C.S., Chung, S.K., 2008. Pectinase assisted extraction of polyphenols from apple pomace. Chin. J. Anal. Chem. 36 (3), 306
310. Zhong-Tao, S., Lin-Mao, T., Cheng, L., Jin-Hua, D., 2009. Bioconversion of apple pomace into a multienzyme bio-feed by two mixed strains of Aspergillus niger in solid state fermentation. Electron. J. Biotechnol. 12 (1), 2
3.

Further reading Awad, M.A., de Jager, A., van Westing, L.M., 2000. Flavonoid and chlorogenic acid levels in apple fruit: characterisation of variation. Sci. Horticult. 83 (3
4), 249
263. Bravo, L., 1998. Polyphenols: chemistry, dietary sources, metabolism, and nutritional significance. Nutr. Rev. 56 (11), 317
333. Constenla, D., Ponce, A.G., Lozano, J.E., 2002. Effect of pomace drying on apple pectin. LWT-Food Sci. Technol. 35 (3), 216
221. de Oliveira, R.C., Doceˆ, R.C., de Barros, S.T.D., 2012. Clarification of passion fruit juice by microfiltration: analyses of operating parameters, study of membrane fouling and juice quality. J. Food Eng. 111 (2), 432
439. ˇ ´ Ðilas, S., Canadanovi´ c-Brunet, J., Cetkovi´ c, G., 2009. By-products of fruits processing as a source of phytochemicals. Chem. Ind. Chem. Eng. Quar. 15 (4), 191
202. Cebulj, A., Cunja, V., Mikulic-Petkovsek, M., Veberic, R., 2017. Importance of metabolite distribution in apple fruit. Sci. Horticult. 214, 214
220. El Gharras, H., 2009. Polyphenols: food sources, properties and applications—a review. Int. J. Food Sci. Technol. 44 (12), 2512
2518. Figuerola, F., Hurtado, M.L., Este´vez, A.M., Chiffelle, I., Asenjo, F., 2005. Fiber concentrates from apple pomace and citrus peel as potential fiber sources for food enrichment. Food Chem. 91 (3), 395
401. Fernandez de Simon, B., Perez-Ilzarbe, J., Hernandez, T., Gomez-Cordoves, C., Estrella, I., 1992. Importance of phenolic compounds for the characterization of fruit juices. J. Agric. Food Chem. 40 (9), 1531
1535. Food and Drug Administration, 2016. Substances generally recognized as safe; final rule. Fed. Regist. 81, 54959
55055. Hicks, D. (Ed.), 1990. Production and Packaging of Non-Carbonated Fruit Juices and Fruit Beverages (No. 663.63/H631). Blackie, London. Joshi, V.K., Sandhu, D.K., 1996. Preparation and evaluation of an animal feed byproduct produced by solid-state fermentation of apple pomace. Bioresour. Technol. 56 (2
3), 251
255. Lamikanra, O. (Ed.), 2002. Fresh-Cut Fruits and Vegetables: Science, Technology, and Market. CRC Press. Le Bourvellec, C., Bouzerzour, K., Ginies, C., Regis, S., Ple, Y., Renard, C.M., 2011. Phenolic and polysaccharidic composition of applesauce is close to that of apple flesh. J. Food Compos. Anal. 24 (4), 537
547. Linden, G., Lorient, D., 1999. New Ingredients in Food Processing: Biochemistry and Agriculture. CRC Press. Li, X., Wang, X., Chen, D., Chen, S., 2011. Antioxidant activity and mechanism of protocatechuic acid in vitro. Funct. Foods Health Dis. 1 (7), 232
244. Lee, J., Chan, B.L.S., Mitchell, A.E., 2017. Identification/quantification of free and bound phenolic acids in peel and pulp of apples (Malus domestica) using high resolution mass spectrometry (HRMS). Food Chem. 215, 301
310. Łata, B., Trampczynska, A., Paczesna, J., 2009. Cultivar variation in apple peel and whole fruit phenolic composition. Sci. Horticult. 121 (2), 176
181. Mattila, P., Kumpulainen, J., 2002. Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection. J. Agric. Food Chem. 50 (13), 3660
3667. Mattila, P., Hellstro¨m, J., 2007. Phenolic acids in potatoes, vegetables, and some of their products. J. Food Compos. Anal. 20 (3
4), 152
160. Persic, M., Mikulic-Petkovsek, M., Slatnar, A., Veberic, R., 2017. Chemical composition of apple fruit, juice and pomace and the correlation between phenolic content, enzymatic activity and browning. LWT-Food Sci. Technol. 82, 23
31. Rami´c, M., Vidovi´c, S., Zekovi´c, Z., Vladi´c, J., Cvejin, A., Pavli´c, B., 2015. Modeling and optimization of ultrasound-assisted extraction of polyphenolic compounds from Aronia melanocarpa by-products from filter-tea factory. Ultrason. Sonochem. 23, 360
368. Tucker, G.S., 2003. Food Biodeterioration and Methods of Preservation. Blackwell Publishing, Oxford, pp. 32
64. US Apple Association, 2016. Production and utilization analysis. ,http://www.usapple.org.. Versari, A., Biesenbruch, S., Barbanti, D.A., Farnell, P.J., 1997. Adulteration of fruit juices: dihydrochalcones as quality markers for apple juice identification. LWT-Food Sci. Technol. 30 (6), 585
589. van der Sluis, A.A., Dekker, M., van Boekel, M.A., 2005. Activity and concentration of polyphenolic antioxidants in apple juice. 3. Stability during storage. J. Agric. Food Chem. 53 (4), 1073
1080. Wikiera, A., Mika, M., Starzy´nska-Janiszewska, A., Stodolak, B., 2015b. Development of complete hydrolysis of pectins from apple pomace. Food Chem. 172, 675
680. Wang, X., Lu¨, X., 2014. Characterization of pectic polysaccharides extracted from apple pomace by hot-compressed water. Carbohydr. Polym. 102, 174
184.

Chapter 3

Apricot Estefanı´a Gonza´lez-Garcı´a, Marı´a Luisa Marina and Marı´a Concepcio´n Garcı´a Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Science, Chemical Research Institute “Andre´s M. del Rı´o” (IQAR), University of Alcala´, Madrid, Spain

Chapter Outline 3.1 Introduction 3.2 Apricot kernel 3.2.1 Kernel oil 3.2.2 Kernel: skin and press cake 3.2.3 Essential oil 3.3 Other apricot by-products 3.3.1 Pomace

3.1

43 44 44 52 55 56 56

3.3.2 Thinned apricots 3.3.3 Blanching water concentrate and debittering water concentrate 3.4 Application of apricot by-products 3.5 Conclusions and future trends Acknowledgments References

58 58 58 61 61 61

Introduction

Apricot (Prunus armeniaca L.) is a stone fruit belonging to the Prunus genus of the Prunoideae subfamily from the Rosaceae family. This fruit has its origin in China, but it has been long cultivated in Armenia, hence the armeniaca term. Nowadays it is extensively grown worldwide, mainly in temperate regions. In 2016 the world production of apricots was 3,881,204 tons and the main producers were Turkey, Uzbekistan, Iran, Algeria, Italy, Pakistan, Spain, and France, accounting for 67% of the whole global production (FAOSTAT (Food and Agricultural Organization of the United Nations), 2018). The fruit is harvested between May and August, is round or ellipsoidal, 3
6 cm in size, and shows a longitudinal groove. It presents a velvety yellowish-orange skin with reddish shadows. Its yellowish-orange flesh surrounds a woody stone with the seed inside (kernel). Fig. 3.1 shows a scheme of the apricot and its different parts. Apricots can be consumed fresh, dried, or processed into canned apricots, jams, juices, or liquors. Only 10% of the production is utilized as fresh product, while the rest is stored and submitted to different processes: washing, sorting, selecting, drying, cutting, and packaging (Gezer et al., 2002). These processes result in the generation of a large amount of residues, mainly composed of stones, constituted by the shell and the kernel (see Fig. 3.1). These by-products represent, approximately, 6.5% and 1.3%, respectively, of the whole fruit (Alpaslan and Hayta, 2006). Apricot processing generates more than 300,000 tons of residues per year. The improper management and disposal of these residues can trigger environmental pollution and health risks. Apricot kernel shells have been employed for the production of biodiesel (Fadhil, 2017; Yadav et al., 2017) and energy (Buyukada and Aydogmus, 2018), the preparation of active carbons (Zhu et al., 2013), or as sorbent for water and wastewater cleanup (Sostaric et al., 2018; Torosyan et al., 2011). On the other hand, the kernels are traditionally used in the production of cosmetics, medicines, scents, and bakery products or directly consumed as appetizers (Raj et al., 2012; Athar and Nasir, 2005; Durmaz and Alpaslan, 2007). However, their direct consumption is not recommended since apricot kernels contain cyanogenic glycosides, such as amygdaline (D(-)-mandelonitrile β-gentiobioside). Although intact amygdalin is not toxic, its alkaline hydrolysis in the small intestine by the enzyme β-glucuronidase produces glucose, benzaldehyde, and hydrocyanic acid, which has a toxic effect in organisms (Raj et al., 2012). Its concentration can vary within bitter and sweet apricot varieties. While bitter apricot kernels may contain 4
6 g amygdalin/ 100 g kernel, sweet apricot kernels present less than 1 g amygdalin/100 g kernel (Yildirim and Askin, 2010). Despite Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00003-4 © 2020 Elsevier Inc. All rights reserved.

43

44

Valorization of Fruit Processing By-products

FIGURE 3.1 Scheme of the apricot and its parts.

these applications, a huge part of these residues is still underused. This fact supposes an important loss of resources since apricot kernels are rich in proteins, fatty acids, minerals, essential amino acids, and other valuable compounds (Alpaslan and Hayta, 2006). This chapter groups the most recent works (2008
18) devoted to the study of the different by-products generated during apricot processing: kernel (kernel oil, press cake, skin, and essential oil), fruit pomace, thinned apricots, and wastewaters. Moreover, the application of these by-products has also been discussed.

3.2

Apricot kernel

Apricot kernel is, by far, the most revalorized apricot by-product. Many valuable compounds have been obtained not only from the whole kernel, but also from the kernel skin, the kernel oil, the left press cake, or the essential oil.

3.2.1

Kernel oil

Apricot kernel oil is much used for the preparation of numerous cosmetics or medicines. In many of these cases it is used instead of more expensive almond oil. Apricot oil is really appreciated for its beneficial effects on the skin, hair, and health. Two main strategies have been employed to extract apricot kernel oil: solvent extraction, using n-hexane or petroleum ether; and mechanical expression, which involves the use of cold presses or oil expellers (Sriti et al., 2011). Traditionally edible oils have been extracted through mechanical strategies, that result in high quality oils. However, the extraction yield is low. On the other hand, solvent extraction is much more effective than mechanical expression and it enables the extraction of up to 99% of total oil. Nevertheless, the numerous steps followed for removing extracting solvents and the coextraction of undesired compounds from cell walls, make these oils of lower quality (Willems et al., 2008). Table 3.1 groups the works devoted to the extraction and analysis of apricot kernel oil that have appeared in the last decade. Solvent extraction is the most popular choice (Dulf et al., 2017; Pop et al., 2015; Senica et al., 2017; Hassanien ¨ zcan et al., 2010; Rai et al., 2014; Orhan et al., 2008; Go´rna´s et al., 2017; Manzoor et al., 2012; Popa et al., 2011; O ¨ et al., 2013; Bachheti et al., 2012; Mattha¨us and Ozcan, 2009, 2015; Mattha¨us et al., 2015) and petroleum ether or nhexane are the most usual solvents, although methanol or chloroform have also been used. Extractions have been carried out at room temperature, using an ultrasound bath, or with Soxhlet or Twisselmann extractors. The use of a mixture of chloroform:methanol (2:1, v/v) resulted in a low oil yield (29.5%). This yield increased by the prior solid-state fermentation of kernels with filamentous fungi (35.0%) (Dulf et al., 2017). A similar yield (30.1%) was obtained by Hassanien et al. (2014) using hexane as the extraction solvent. Temperature is another important parameter that can affect oil extractability. Indeed extractions carried out at room temperature usually require longer extraction times. Orhan et al. (2008) observed that the use of an ultrasound bath and the slight increase in temperature enabled a significant reduction in the extraction times previously employed (2 days) to extract the apricot kernel oil. In other work Go´rna´s et al. (2017) extracted the apricot kernel oil in an ultrasound bath in just 5 min at a temperature of 35 C. Soxhlet and Twisselmann extractors have also been used to obtain oilseeds. Both instruments enable extraction under reflux, using a discontinuous flow, in the case of the Soxhlet extractor, or a continuous flow, in the Twisselmann extractor (Noke et al., 2013). An additional difference is that the Soxhlet extractor can allow the loss of part of the oil if the solvent is vaporized very fast (Barthet and Daun, 2004). In general, these processes are long and require a few hours to be completed. In fact the reference procedure of the International Standard ISO 659:1998 (ISO, 1998) describes the ¨ zcan, 2009, extraction of oil using hexane or petroleum ether and a Twisselmann extractor for 6 h (Mattha¨us and O 2015; Mattha¨us et al., 2015). Furthermore, all solvent extractions require the posterior recovery of solvents containing

TABLE 3.1 Extraction methodology, yield, presence of bioactive compounds, and composition of the apricot kernel oil. Oil extraction method

Oil yield

Bioactive compounds

Composition

Ref.

5 g seed 1 60 mL chloroform/methanol (2:1, v/v)

29.5% with nonfermented kernels

Fatty acids

[Oleic acid] 5 51.5% [Linoleic acid] 5 32.3% [Palmitic acid] 5 7.3% [Stearic] 5 2.8%

Dulf et al. (2017)

35.0% with fermented kernels

Fatty acids

[Oleic acid] 5 53.90
54.10% [Linoleic acid] 5 35.21
36.20% [Palmitic acid] 5 3.80
4.80% [Stearic] 5 1.00
1.15%

20 g freeze-dried kernel 1 250 mL methanol/ethyl acetate/petroleum ether (1:1:1, v/v/v), filtering, reextraction (twice), combining, partitioning with water-diethyl ether-saturated saline solution, recovering of the organic phase, and evaporation to dryness




Carotenoids (0.58 mg/100 mg kernel)

[Lycopene] 5 84.2%

Tocochromanols (13.1 mg/100 g kernel)

[α-Tocopherol] 5 0.8 mg/100 g kernel [γ-Tocopherol] 5 11.2 mg/100 g kernel [δ-Tocopherol] 5 0.9 mg/100 g kernel [α-Tocotrienol] 5 0.3 mg/100 g kernel

1 g crushed seeds 1 5 mL methanol/water (70:30, v/v), extraction (30 C, 30 min), centrifugation, and filtration




Phenolics (7.5
21.1 mg/100 g kernel)

[Hydroxycinnamic acids] 5 2.6
5.8 mg/ 100 g kernel [Flavonones] 5 1.6
3.4 mg/100 g kernel [Flavanols] 5 2.6
11.9 mg/100 g kernel

Cyanogenic glycosides (70.2
372.9 mg/ 100 g kernel)

[Amygdalin] 5 63.0
216.2 mg/100 g kernel [Neoamygdalin] 5 0.7
5.2 mg/100 g kernel [Prunasin] 5 6.3
164.7 mg/100 g kernel

Fatty acids

[Oleic acid] 5 66.8% [Linoleic acid] 5 25.8% [Palmitic acid] 5 5.0%

Tocochromanols (58.9 mg/100 g oil)

[γ-Tocopherol] 5 56.1 mg/100 g oil [α-Tocopherol] 5 2.8 mg/100 g oil

Phytosterols (176.2 mg/100 g oil)

[β-Sitosterol] 5 155.5 mg/100 g oil [Campesterol] 5 9.9 mg/100 g oil [Δ5-avenasterol] 5 2.0 mg/100 g oil

10 g kernel 1 100 mL n-hexane, separation, and evaporation

30.1%

Pop et al. (2015)

Senica et al. (2017)

Hassanien et al. (2014)

Ground seeds maceration with n-hexane (2 days) and concentration

21.8%
43.6%

Fatty acids

[Oleic acid] 5 43.6
68.7% [Linoleic acid] 5 16.8
34.8% [Palmitic acid] 5 7.2
20.1%

Orhan et al. (2008)

5 g kernels 1 25 mL n-hexane, mixing, ultrasonic bath (35 C, 5 min), supernatant collection, and reextraction (twice)

27.2%
61.4%

Tocochromanols (78.8
258.5 mg/ 100 g oil)

[γ-Tocopherol] 5 73.7
237.2 mg/100 g oil [α-Tocopherol] 5 1.5
11.6 mg/100 g oil [δ-Tocopherol] 5 3.4
8.4 mg/100 g oil [α-Tocotrienol] 5 0.2
1.6 mg/100 g oil

Go´rna´s et al. (2017)

Carotenoids (0.15
0.53 mg/ 100 g oil)

[Lutein] 1 [zeaxanthin] 1 [β-cryptoxanthin] 1 [β-carotene] 5 76
94% (Continued )

TABLE 3.1 (Continued) Oil extraction method

Oil yield

Bioactive compounds

Composition

Ref.

Removing of seed coating, 50 g crushed seeds 1 250 mL n-hexane (Soxhlet, 6 h), and solvent evaporation

32.2%
42.5%

Fatty acids

[Oleic acid] 5 62.3
80.9% [Linoleic acid] 5 13.1
30.3% [Palmitic acid] 5 3.4
5.9% [Linolenic acid] 5 0.7
1.0% [Stearic acid] 5 1.1
1.7%

Manzoor et al. (2012)

Tocochromanols

[α-Tocopherol] 5 1.5
4.0 mg/100 g [γ-Tocopherol] 5 33.1
52.1 mg/100 g [δ-Tocopherol] 5 2.9
6.0 mg/100 g

Tocochromanols

[α-Tocopherol] 5 ND
0.04 mg/100 g [β 1 γ-Tocopherol] 5 0.15
1.25 mg/100 g [δ-Tocopherol] 5 0.03
0.06 mg/100 g

Carotenoids

β-Carotene 5 6.11 mg/100 g oil

Phenolic compounds

TPC 5 0.88
1.30 mM gallic acid/L

Petroleum ether extraction in a Soxhlet system




Popa et al. (2011)

Extraction with petroleum ether (Soxhlet, 30 C
60 C, 6 h), drying over anhydrous sodium sulfate, solvent rotary evaporation

42.2%
57.2%

Fatty acids

[Oleic acid] 5 53.1
70.9% [Linoleic acid] 5 21.4
35.7%

¨ zcan O et al. (2010)

Powdered seeds extracted with petroleum ether (Soxhlet, 40 C
60 C, 6 h), drying over anhydrous sodium sulfate, and solvent rotary evaporation

44.3%

Fatty acids

[Oleic acid] 5 73.58% [Linoleic acid] 5 19.26% [Palmitic acid] 5 3.37% [Stearic acid] 5 2.68% [Myristic acid] 5 1.18%

Rai et al. (2013)

Phenolic compounds

TPC 5 270 mg/100 g oil

Ground seeds drying, extraction with petroleum ether (60 C
80 C, Soxhlet extractor), and solvent eliminated by distillation

44.3%

Fatty acids

[Oleic acid] 5 73.58% [Linoleic acid] 5 19.26% [Palmitic acid] 5 3.31% [Stearic acid] 5 2.68% [Myristic acid] 5 1.18%

Bachheti et al. (2012)

2 g ground seeds 1 70 mL petroleum ether (Twisselmann extractor, 6 h), solvent rotary evaporation, and drying with nitrogen stream

46.3
55.4 g/ 100 g

Fatty acids

[Oleic acid] 5 62.3
71.6 g/100 g [Linoleic acid] 5 18.7
28.0 g/100 g [Palmitic acid] 5 4.9
5.7 g/100 g

Tocochromanols (18.5
44.0 mg/ 100 g)

[γ-Tocopherol] 5 13.3
33.0 mg/100 g [α-Tocotrienol] 5 2.6
3.1 mg/100 g [δ-Tocopherol] 5 0.4
3.9 mg/100 g [α-Tocopherol] 5 0.1
3.8 mg/100 g

Mattha¨us and ¨ zcan O (2009)

(Continued )

TABLE 3.1 (Continued) Oil extraction method

Oil yield

Bioactive compounds

Composition

Ref.

2 g ground seeds 1 70 mL petroleum ether (Twisselmann extractor, 6 h), solvent rotary evaporation, and drying with nitrogen stream

Sweet seeds: 53.4 g/100 g

Fatty acids

[Oleic acid] 5 68.3 g/100 g [Linoleic acid] 5 23.1 g/100 g [Palmitic acid] 5 4.9 g/100 g

Tocochromanols (72.3 mg/100 g)

[γ-Tocopherol] 5 67.3 mg/100 g [α-Tocopherol] 5 2.8 mg/100 g [δ-Tocopherol] 5 2.2 mg/100 g

Mattha¨us and ¨ zcan O (2015)

Fatty acids

[Oleic acid] 5 57.8 g/100 g [Linoleic acid] 5 31.4 g/100 g [Palmitic acid] 5 6.4 g/100 g

Tocochromanols (86.6 mg/100 g)

[γ-Tocopherol] 5 81.0 mg/100 g [α-Tocopherol] 5 3.1 mg/100 g [δ-Tocopherol] 5 2.5 mg/100 g

Fatty acids

[Oleic acid] 5 41.1
66.8% [Linoleic acid] 5 24.4
45.6% [Palmitic acid] 5 4.9
7.1%

Tocochromanols (2.4
6.5 mg/100 g)

[γ-Tocopherol] 5 2.3
5.8 mg/100 g

Fatty acids

With skin/unroasted: [Oleic acid] 5 67.8 g/100 g oil [Linoleic acid] 5 25.7 g/100 g oil [Palmitic acid] 5 4.7 g/100 g oil With skin/roasted (180 C): [Oleic acid] 5 68.2 g/100 g oil [Linoleic acid] 5 27.1 g/100 g oil [Palmitic acid] 5 4.9 g/100 g oil No skin/unroasted: [Oleic acid] 5 68.6 g/100 g oil [Linoleic acid] 5 22.5 g/100 g oil [Palmitic acid] 5 4.7 g/100 g oil No skin/roasted (180 C): [Oleic acid] 5 71.8 g/100 g oil [Linoleic acid] 5 21.9 g/100 g oil [Palmitic acid] 5 4.5 g/100 g oil

Phenolic compounds

TPCskin/unroasted 5 1.0 μg GAE/g oil TPCno skin/unroasted 5 0.2 μg GAE/g oil TPCskin/roasted 5 3.3 μg GAE/g oil TPCno skin/roasted 5 1.2 μg GAE/g oil

Bitter seeds: 45.2 g/100 g

2 g ground seeds 1 70 mL petroleum ether (Twisselmann extractor, 6 h), solvent rotary evaporation, and drying with nitrogen stream

Kernel sample (kernels with and without skin) roasted at different temperatures (120 C, 150 C, and 180 C, 10 min), and cold pressing of kernels with a lab-type oil press

28.0
50.2 g/ 100 g




Mattha¨us et al. (2015)

Zhou et al. (2018)

(Continued )

TABLE 3.1 (Continued) Oil extraction method

Oil yield

Bioactive compounds

Composition

Ref.

Kernels crumbling and sift, roasting (180 C for 0, 5, 10, 15, 20, and 30 min), and oil extraction by cold pressing with a lab-type oil press




Fatty acids

[Oleic acid] 5 68.3
68.7% [Linoleic acid] 5 23.2
23.6% [Palmitic acid] 5 6.0%

Durmaz et al. (2010)

Tocochromanols

[α-Tocopherol] 5 2.1
2.4 mg/100 g oil [γ-Tocopherol] 5 37.5
45.2 mg/100 g oil [δ-Tocopherol] 5 1.2
1.3 mg/100 g oil

Fatty acids

[Oleic acid] 5 62.1
70.7% [Linoleic acid] 5 20.5
27.8% [Palmitic acid] 5 5.0
7.8% [Linolenic acid] 5 0.4
1.4%

Tocochromanols (72
193.7 mg/ 100 g)




Carotenoids (0.262
0.267 mg/ 100 g)










Bisht et al. (2015)

Passing apricot kernels through a table oil expeller and filtration through a filter press

3 kg powdered kernels 1 0.3% cellulase/pectinase combination (50 C, 2 h). Oil extraction with an oil expeller

45.6%
46.3%

Control: 33.1%

Gupta et al. (2012)

Enzymes treatment: 47.3%





Tocochromanols (45.2
77.3 mg/ 100 g kernel)

[α-Tocopherol] 5 1.4
4.4 mg/100 g kernel [γ-Tocopherol] 5 42.5
73.3 mg/100 g kernel [δ-Tocopherol] 5 0.8
2.1 mg/100 g kernel

Go´rna´s et al. (2015)







Sterols (215.7
973.6 mg/ 100 g oil)

[β-Sitosterol] 5 4.5
821.5 mg/100 g oil [Cholesterol] 5 0.3
52.6 mg/100 g oil [Campesterol] 5 0.2
48.7 mg/100 g oil [Δ5-Avenasterol] 5 0.2
27.6 mg/100 g oil

´ Rudzinska et al. (2017)

Squalene (12.6
43.9 mg/ 100 g oil)




TPC, total phenolic content.

Apricot Chapter | 3

49

the oil, the evaporation/concentration under reduced pressure/vacuum and/or at elevated temperature, and, in some cases, drying. Both Soxhlet and Twisselmann extractors are available at pilot scale, and thus can be used at an industrial level to extract the oil from apricot kernels (Kukula-Koch et al., 2015). However, they require high solvent volumes, which are not suitable from an environmental point of view. Unlike solvent extraction, mechanical strategies, such as oil presses and expellers, do not need solvents and are more sustainable. Nevertheless, they have been less exploited and need a greater development (Zhou et al., 2018; Durmaz et al., 2010; Gupta et al., 2012; Bisht et al., 2015). Oil content and, thus, the oil yield, can greatly vary among apricot varieties. Indeed, the Kalecik variety showed half of the oil yield of the Malatya variety (21.8% and 43.6%, respectively) when the oil was extracted with hexane at room temperature for 2 days (Orhan et al., 2008). A more significant difference was found by Go´rna´s et al., who observed that HL PSSˇ 5 variety produced only 27.2% of oil compared to 61.4% from Veselka variety when extracting with hexane in an ultrasonic bath at 35 C for 5 min (Go´rna´s et al., 2017). On the other hand, Mattha¨us et al. found out ¨ zcan, 2015) and that that sweet kernels were more profitable for the extraction of oil than bitter kernels (Mattha¨us and O the harvest time greatly influenced the yield, achieving increases of up to 20% in 3 weeks (Mattha¨us et al., 2015). Additionally, the treatment of kernels with enzymes could also enhance the oil extraction yield. In fact the treatment of the powdered kernels with 0.3% of an enzyme mixture (cellulase 1 pectinase) for 2 h at 50 C enabled an increase in the oil extraction yield from 33.1% to 47.3% in an apricot variety from India (Bisht et al., 2015). Regarding composition, the apricot kernel oil is rich in fatty acids and presents a great variety of minor high-value compounds such as tocochromanols, phytosterols, carotenoids, and phenolic compounds.

3.2.1.1 Fatty acids Fatty acids are monocarboxylic organic acids constituted by a chain of up to 80 carbon atoms, although most naturally occurring and appreciated fatty acids present between 10 and 22 carbons. They can present double bonds which makes it possible to differentiate between saturated fatty acids (SFAs) and unsaturated fatty acids (UFAs) (Kenar et al., 2017). The most important fatty acids are those that cannot be synthesized by the body and must be obtained through the diet (e.g., UFAs such as linoleic and linolenic acids) (Pasquele, 2009). These are called essential fatty acids and they are involved in the construction and reparation of cell membranes, the production of prostaglandins, the regulation of heart rate and blood pressure, and the performance of the immune system. Moreover, they have shown antitumorigenic properties (Connor, 2000; Torres-Duarte and Vanderhoek, 2003). As shown in Table 3.1, apricot kernel oils present high concentrations of UFAs and low concentrations of SFAs. The main fatty acid in the apricot kernel oil is the oleic acid (C18:1), followed by linoleic acid (C18:2), palmitic acid (C16:0), linolenic acid (C18:3), stearic acid (C18:0), and myristic acid (C14:0). Fatty acids content depends on the apricot variety and factors such as soil properties, climate, and harvest environmental conditions (Orhan et al., 2008). Studies carried out with sweet and bitter apricot kernels demonstrated that the oil from sweet kernels is richer in oleic acid than the oil from bitter kernels, while bitter kernels presented higher amount of linoleic and palmitic acids ¨ zcan, 2015). On the other hand, the studies of Zhou’s group (Zhou et al., 2018) revealed that the ther(Mattha¨us and O mal pretreatment of kernels, usually employed to increase oil yield, did not have any significant influence on the profile and content of fatty acids. However, the presence of the kernel skin increased the concentration of linoleic acid and decreased the concentration of oleic acid. Furthermore, the previous fermentation of the kernels by filamentous fungi increased the content of UFAs and thus the oil quality (Dulf et al., 2017).

3.2.1.2 Vitamin E active compounds: tocopherols and tocotrienols Vitamin E active compounds refer to a group of vitamers (isoforms of vitamins) constituted by four tocopherols and four tocotrienols, collectively known as tocochromanols. All tocochromanols present a chromanol ring and a polyprenyl lateral chain. The main difference between tocopherols and tocotrienols is on this chain; while tocopherols have a saturated chain, tocotrienols possess an unsaturated chain with three double bonds (C-3, C-7, and C-11). Within tocochromanols there are four homologues, designated by the Greek letters α, β, γ, and δ, that differ in the number and position of methyl groups in the chromanol ring (Sayago et al., 2007). The eight vitamers are lipid-soluble molecules that appear in the unsaponifiable lipid fraction of kernel oils. They are essential since they cannot be synthesized by the human organism. The health benefits of tocochromanols have been widely studied. They protect lipids and other membrane components against oxidative damage (Falk and MunneBosch, 2010) and possess anticancerogenic effects (Srivastava and Gupta, 2006). Although α-tocopherol, the most

50

Valorization of Fruit Processing By-products

abundant vitamer, has been traditionally considered the most active form of vitamin E, this fact is not completely proved, and many works indicate that γ-tocopherol or tocotrienols could be more active (Yoshida et al., 2003). As seen in Table 3.1 apricot kernel oil can present high contents of tocochromanols, although it is strongly affected by the genotype. The variety with the highest tocochromanols content is Veselka with 258.5 mg/100 g oil (Go´rna´s et al., 2017). The most abundant vitamer in Veselka kernel oil is γ-tocopherol, followed by α-tocopherol, while the rest of tocopherol homologues and tocotrienols are in trace concentrations (Pop et al., 2015; Go´rna´s et al., 2017, 2015). As ¨ zcan (2015), bitter apricot kernels presented slightly higher contents of tocochromanols demonstrated by Mattha¨us and O than sweet kernels. This behavior was opposite to that observed with regards to oil yield, which was higher in sweet kernels. This tendency was also observed by Go´rna´s et al., who concluded that tocochromanols content and oil yield were negatively correlated (Go´rna´s et al., 2017). The effect of the harvest time was also considered by Mattha¨us et al. (2015). They observed that γ-tocopherol content could decrease by half in 2 or 3 weeks of maturation, while the rest of the tocochromanols did not present a significant variation. Similarly the roasting of kernels considerably decreased γ-tocopherol content but did not affect α-tocopherol and δ-tocopherol contents (Durmaz et al., 2010).

3.2.1.3 Triterpenoids: phytosterols/phytostanols and squalene Plant sterols or phytosterols and their saturated derivatives, phytostanols, are a group of compounds that belong to the triterpenoids family. They are constituted by a tetracyclic structure with a side chain in the C17 position. They are cholesterol analogues differing in the substitution of the C4 and C24 carbons and in the number and position of the unsaturations in the rings and the side chain (Moreau et al., 2018). Their beneficial health effects have been widely studied, specially their cholesterol-lowering properties (Chen et al., 2008). This effect is associated with their capability to decrease cholesterol absorption and cholesterol synthesis (Calpe-Berdiel et al., 2009). Phytosterols, such as β-sitosterol, campesterol, or stigmasterol, have been utilized in the elaboration of nutraceuticals for cholesterol-lowering purposes. Moreover, they can also be applied to the production of enriched edible oils, butters, or margarines (Chen et al., 2008; Weststrate and Meijer, 1998). Since the absorption of phytosterols by the intestine is approximately half the intake and the absorption of phytostanols is even lower, the consumption of enriched foods is favored for the reduction of cholesterol levels (Chen et al., 2008). Apricot kernel oil is rich in phytosterols, although they have scarcely been studied (see Table 3.1). Like other compounds the phytosterols content in kernel oil depends greatly on the apricot variety and ranges between 176.2 and 973.6 mg/100 g oil (Hassanien et al., 2014; Rudzi´nska et al., 2017). Rudzi´nska et al. (2017) identified nine sterols in apricot kernel oil (β-sitosterol, campesterol, Δ5-avenasterol, Δ7-stigmasterol, gramisterol, cholesterol, 24-methylenecycloartanol, Δ7-avenasterol, and citrostadienol) with β-sitosterol, campesterol, and Δ5-avenasterol being the most abundant. Additionally, Hassanien et al. (2014) also identified sitostanol and campestanol among apricot kernel phytosterols, although in concentrations lower than 1% of total phytosterols. On the other hand, squalene is a linear triterpene compound synthesized by animals or plants. It is the precursor for the synthesis of steroid hormones, vitamins (e.g., vitamin D), cholesterol, and other sterols. Squalene has great health benefits that include the reduction of cholesterol levels as well as antioxidant, antibacterial, and anticancer properties (Lozano-Grande et al., 2018). Squalene concentration in the apricot kernel oil ranged from 12.6 to 43.9 mg/100 g oil depending on the apricot variety (Rudzi´nska et al., 2017). These values are higher than those observed in edible nuts such as hazelnut, macadamia, peanut, walnut, or almond (Maguire et al., 2004), but lower than those found in amaranth (2000
8000 mg/100 g oil) (Naziri et al., 2011) or olive (150
747 mg/100 g oil) (Salvo et al., 2017). Although both mechanical expression and solvent extraction can be utilized to extract squalene, the mechanical methodology is preferred since it results in a less modified and higher-quality squalene.

3.2.1.4 Carotenoids Carotenoids are another group of compounds commonly found in oils. They are naturally occurring pigments present in most vegetables and fruits which are also essential for the human body. They possess antioxidant and antiinflammatory capacities, prevent the development of cardiovascular diseases and cancer, improve cognitive functions, and provide benefits to ocular health, among others (Eggersdorfer and Wyss, 2018). They can be classified into two different groups: carotenes and xanthophylls. Carotenes are constituted by a hydrocarbon chain with four carbon atoms, while xanthophylls are oxygen derivatives of carotenoids. Carotenoids such as β-carotene, lutein, and zeaxanthin are commercialized as supplements or used to produce functional foods. Moreover, they have been also utilized as colorants in foods and beverages and even in pharmaceutical formulations (Eggersdorfer and Wyss, 2018).

Apricot Chapter | 3

51

80

Contents of individual carotenoids (%)

70

60

50

40

30

20

10

Neoxanthin

Not identified

Antheraxanthin

Lutein

Zeaxanthin

beta-Cryptoxanthin

ok m Po gr e

Sp

ic

a

s zi D

ld

nt

es

ar

1

a gu Ap

Ap Violaxanthin

Ilg

ga D

gu

ld

ai

3 es

64 50

a as R

07 11

01

g er sb Ai

el

ka

s Ve s

ve i el Ed

es ld gu Ap

H

L

PS

S

4

5

0

beta-Carotene

FIGURE 3.2 Individual carotenoids contents (%) in kernel oils recovered from different apricot varieties. Results are expressed as means 6 standard ´ deviations (n 5 3). Reproduced with permission from Go´rna´s, P., Radziejewska-Kubzdela, E., Miˇsina, I., Bieganska-Marecik, R., Grygier, A., ´ Rudzinska, M., 2017. Tocopherols, tocotrienols and carotenoids in kernel oils recovered from 15 apricot (Prunus armeniaca L.) genotypes. J. Am. Oil Chem. Soc. 94, 693
699.

As observed in Table 3.1, carotenoids are present in the apricot kernel oil in concentrations ranging from 0.15 to 6.11 mg/100 g oil depending on the apricot genotype (Go´rna´s et al., 2017; Popa et al., 2011; Gupta et al., 2012). Fig. 3.2 shows that lutein, zeaxanthin, β-cryptoxanthin, and β-carotene are the main carotenoids in the apricot kernel oil, while neoxanthin, antheraxanthin, and violaxanthin do not exceed the 10% (Go´rna´s et al., 2017). Surprisingly, other authors could only identify lycopene in the apricot kernel oil (Pop et al., 2015).

3.2.1.5 Polyphenols Polyphenols comprise a group of more than 8000 compounds with extraordinary antioxidant properties. They are secondary metabolites of plants that present aromatic rings and one or more hydroxyl moieties. Depending on the number of phenol rings and the structural elements that bind these rings, polyphenols can be classified into five groups, namely phenolic acids, flavonoids, stilbenes, lignans, and tannins. Phenolic acids may be subdivided into those derived from cinnamic acid (e.g., caffeic acid) and those derived from benzoic acid (e.g., gallic acid). Flavonoids, the most abundant polyphenols with more than 4000 structural varieties, can be divided into anthocyanidins and anthoxanthins. The latter include flavonols, flavanols, flavones, isoflavones, and flavanones (Han et al., 2007; Pandey and Rizvi, 2009). The high antioxidant power of polyphenols is derived from their capacity to scavenge reactive oxygen species (ROS), to remove ROS, and to inhibit the enzymes involved in ROS production (Belˇscˇ ak-Cvitanovi´c et al., 2018). These antioxidant fractions can be used either as functional ingredients in the preparation of supplements or as food antioxidants (Monagas et al., 2007). The apricot kernel oil is also a source of polyphenols (Popa et al., 2011; Rai et al., 2013; Zhou et al., 2018). The oil obtained by Shoxlet extraction with hexane presented a total phenolic content (TPC) of 0.88
1.30 mM gallic acid/L depending on the apricot variety (Popa et al., 2011). In other work, a similar extraction resulted in a TPC of 270 mg/ 100 g oil (Rai et al., 2013). Moreover, Zhou et al. investigated the variation of TPC in the oil extracted after the roasting of kernels with and without skin (see Fig. 3.3). As observed, roasting of peeled kernels at 180 C increased the TPC

52

Valorization of Fruit Processing By-products

3.6 Cb AKO S-AKO

3.2

TPC in oil (μ μg GAE/g)

2.8 Bb 2.4

Bb

2.0 1.6 Ca 1.2

Ab

0.8 0.4

FIGURE 3.3 Effect of roasting on the extraction of phenolic compounds from apricot kernel oil. Different capital letters indicate significant differences between samples under different roasting conditions (Tukey’s test, P , .05); different lowercase letters indicate significant differences between samples under the same roasting conditions (Tukey’s test, P , .05). Reproduced with permission from Zhou, B., Sun, Y., Li, J., Long, Q., Zhong, H., 2018. Effects of seed coat on oxidative stability and antioxidant activity of apricot (Prunus armeniaca L.) kernel oil at different roasting temperatures. J. Am. Oil Chem. Soc. 95, 1297
1306.

Ba Ba

Aa

0.0 Unroasted

120

150

180

Temperature (ºC)

from 0.2 to 1.2 μg gallic acid/g of oil. However, the effect of roasting was even more pronounced in kernels with skin, where TPC increased from 1.0 to 3.3 μg gallic acid/g of oil (Zhou et al., 2018).

3.2.2

Kernel: skin and press cake

The whole kernel, as well as its skin and the press cake remaining from oil extraction, are other by-products obtained during apricot processing. They are rich in bioactive compounds, such as polyphenols, but they are an especially great source of proteins and peptides (see Table 3.2).

3.2.2.1 Polyphenols Polyphenols have been extracted from the whole kernel using methanol/water (70:30, v/v) at 30 C for 30 min obtaining between 7.5 and 21.1 mg/100 g kernel, depending on the genotype. However, most polyphenols are concentrated in the kernel skin. In fact, despite the kernel skin representing just 8% of the total kernel weight, it contains around 88% of total polyphenols in the kernel. Han et al. (2013), extracted polyphenols from the kernel skin and observed that the methodology employed to obtain the skins influenced both the TPC and the radical-scavenging activity (RSA) of extracts. The blanching treatment at 95 C for 3 min resulted in an RSA of 66.6%, while the skins obtained by water immersion or acid immersion showed lower RSAs (63.8% and 58.3%, respectively). Furthermore, the technique employed to extract kernel skin polyphenols also affected their RSA. Microwave-assisted extraction of polyphenols from kernel skins using methanol resulted in better results (RSA 5 66.6%) than the use of ultrasonic-assisted extraction or solvent extraction (RSA 5 45.3% and 35.2%, respectively). Regarding polyphenols composition, hydroxycinnamic acids, flavonones, and flavonols are the main components of the whole apricot kernel (Senica et al., 2017), while chlorogenic acids, procyanidins, and propelargonidins are the most abundant in the kernel skin (Han et al., 2013).

3.2.2.2 Proteins There is an increasing protein demand mainly driven by the increasing world population. For that reason the search for new and cheap protein sources has attracted, in recent years, much attention. Fruit kernels present high protein contents and thus constitute a cheap alternative to other protein sources. Protein extraction from vegetable sources is a challenging process and usually requires the use of alkali conditions, denaturing, reducing, or chaotropic agents and/or ultrasounds (Wu et al., 2014; Feist and Hummon, 2015; Geciova et al., 2002). Moreover, a purification step, frequently based on protein precipitation, is usually required. The amount of proteins extracted from apricot kernels depends on the apricot variety and the used methodology

Apricot Chapter | 3

53

TABLE 3.2 Extraction method, composition, and activity of bioactive compounds obtained from different apricot byproducts. Byproduct

Bioactive compounds

Extraction of bioactive compounds

Composition/activity

Ref.

Kernel skins

Phenolic compounds (TPC 5 2204 mg gallic acid/100 g skin)

Skins removal: kernels blanching with water (95 C, 3 min), manual removing, oven-drying (45 C), milling, and sifting (40-mesh)

Mainly chlorogenic acids, procyanidins, and propelargonidins

Han et al. (2013)

Phenolic compounds extraction: 1 g skin 1 44.5 mL ethanol (43%, v/v), microwave-assisted extraction (400 W, 78.21 C, 17.6 min), filtration, and condensation Whole kernel

Proteins (175 proteins)

0.5 g ground kernels, washing with hexane, protein extraction (12 mL extraction buffer (1 M urea, 50 mM Tris
HCl pH 8.0, 1% CHAPS, 60 mM DTT), 4 C, 2 h), centrifugation, supernatant recovery, protein precipitation (13% TCA and 0.007% β-mercaptoethanol in acetone,
20 C overnight and 4 C for 2 h), centrifugation, and pellet recovery

Nucleotide binding proteins (20.9%), hydrolase activity proteins (10.6%), kinase activity proteins (7%), and catalytic activity proteins (5.6%)

Ghorab et al. (2018)

Kernel press cake

Proteins (protein yield 5 71.3%)

Boiling in water (1:20, w/v, 1 h), protein solubilization (pH 8), filtration, protein coagulation (pH 4), filtration, pressing, drying, and grinding




Sharma et al. (2010)

Whole kernel

Proteins (23 g/100 g defatted and dried seed)

30 mg defatted seeds 1 5 mL extraction buffer (Tris
HCl (100 mM, pH 7.5) 1 SDS (0.5%, w/v) 1 DTT (0.5%, w/v)), high-intensity focused ultrasound probe (30% amplitude, 1 min), centrifugation, supernatant recovery, protein precipitation (acetone, 4 C, 15 min), centrifugation, and pellet recovery




Garcı´a et al. (2016)

Antioxidant, ACEinhibitory and hypocholesterolemic peptides

Simulated gastrointestinal digestion with pepsin and pancreatin In vitro digestion with Alcalase (borate buffer, pH 8.5, 0.15 AU/g protein, 50 C, 4 h), Thermolysin (phosphate buffer, pH 8.0, 0.05 g enzyme/g protein, 50 C, 4 h), or flavourzyme (phosphate buffer, pH 8.0, 75 AU/g protein, 50 C, 8 h), enzyme inactivation (100 C, 10 min), centrifugation, and supernatant recovery

Gastrointestinal hydrolysate: ABTS scavenging capacity  58% IC50 5 140 μg/mL Micellar cholesterol solubility inhibition , 1% Alcalase hydrolysate (DH 5 59%): ABTS scavenging capacity  81% Micellar cholesterol solubility inhibition , 1% Thermolysin hydrolysate (DH 5 60%): ABTS scavenging capacity  55% IC50 5 140 μg/mL Micellar cholesterol solubility inhibition  33% Flavourzyme hydrolysate (DH 5 46%): ABTS scavenging capacity  50% Micellar cholesterol solubility inhibition , 1% (Continued )

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Valorization of Fruit Processing By-products

TABLE 3.2 (Continued) Byproduct

Bioactive compounds

Extraction of bioactive compounds

Composition/activity

Ref.

Whole kernel

ACE-inhibitory peptides

Alkali extraction and acid precipitation

Protamex: DH 5 7.5%, ACE-inh 5 76%

Zhu et al. (2010)

Protein (2%, v/v) hydrolysis with different enzymes (Protamex, pH 7.0, 50 C; Alcalase 2.4 L, pH 8.0, 55 C; Proleather FG-F, pH 10, 60 C; Neutrase, pH 7.0, 50 C; Flavourzyme, pH 7.0, 50 C; papain, pH 7.0, 55 C) (240 min), enzyme inactivation (90 C, 10 min), neutralization, centrifugation, and supernatant lyophilization

Alcalase 2.4 L: DH 5 18%, ACE-inh 5 82%

Whole kernel

ACE-inhibitory peptides

Protein extraction: 30 mg defatted seeds 1 5 mL extraction buffer (Tris
HCl (100 mM, pH 7.5) 1 SDS (0.5%, w/v) 1 DTT (0.5%, w/v)), highintensity focused ultrasound probe (30% amplitude, 5 min), centrifugation, supernatant recovery, protein precipitation (acetone (1:2), 220 C, 1 h), centrifugation, and pellet recovery

Proleather FG-F: DH 5 18%, ACE-inh 5 67% Neutrase: DH 5 5%, ACE-inh 5 69% Flavourzyme: DH 5 5%, ACE-inh 5 4% Papain: DH 5 3%, ACE-inh 5 74% [IYSPH] 5 319
607 μg/g kernel [IYTPH] 5 13.2
20.6 μg/g kernel [IFSPR] 5 112
357 μg/g kernel [VAIP] 5 26.4
46 μg/g kernel

Gonza´lezGarcı´a et al. (2018)

DH 5 34.1 6 5.3% Yield 5 72.4 6 2.3%

Wang et al. (2010)

In vitro digestion: pellet solution (5 mg/mL, in phosphate buffer (5 mM, pH 8.0)), hydrolysis with thermolysin (0.05 g enzyme/g protein, 50 C, 4 h), inactivation of enzyme (100 C, 10 min), centrifugation, and supernatant recovery Hydrolysate fractionation: molecular weight cut-off filters (3 kDa, 7000 3 g, 90 min) Kernel meal

Oligopeptides

Defatted kernel meal in water (2%, w/v), stirring (85 C, 15 min), hydrolysis with Neutrase 0.8 L/N120P (2:1, E/S 5 7200 U/g, pH 6.5, 52.5 C, 173 min), hydrolysis stop (90 C, 10 min), cooling at room temperature, centrifugation, and freeze-drying of supernatant

ABTS, 2,20 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid; AU, activity units; CHAPS, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate; DH, degree of hydrolysis; DTT, dithiothreitol; IC50, half maximal inhibitory concentration; SDS, sodium dodecyl sulfate; TCA, trichloroacetic acid; Tris, tris (hydroxymethyl)aminomethane.

(Ghorab et al., 2018; Sharma et al., 2010; Garcı´a et al., 2016) (see Table 3.2). Ghorab et al. (2018) extracted proteins from defatted kernels with a buffered solution containing urea, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), and dithiothreitol (DTT). Proteins were then precipitated under acidic conditions, with β-mercaptoethanol and acetone. The obtained extract was submitted to a proteomic study by the previous protein capture using combinatorial peptide ligand libraries. They identified 175 proteins with different activities: nucleotide binding, hydrolase activity, kinase activity, or catalytic activity. In other work (Sharma et al., 2010), apricot kernel proteins were extracted by boiling the press cake and increasing the pH, followed by protein coagulation under acidic conditions. This strategy enabled the extraction of 71.3% of the proteins present in the kernel and to obtain a protein isolate with

Apricot Chapter | 3

55

68.8% of protein. On the other hand, Garcı´a et al. (2016) could extract 23 g of protein per 100 g of dried and defatted kernels when extracting with a Tris
HCl buffer containing sodium dodecyl sulfate (SDS) and DTT under highintensity focused ultrasound followed by precipitation with cold acetone. All these methodologies require large amounts of polluting reagents and organic solvents that are not environmentally friendly. Therefore the development of greener strategies for the extraction of proteins is needed. Some authors have successfully applied nanomaterials for the extraction and purification of proteins from fruit kernels pertaining to the same family as apricot. In fact the use of carbosilane dendrimers with different functional groups enabled the extraction and purification of kernel proteins without requiring solvents (Gonza´lez-Garcı´a et al., 2016, 2017).

3.2.2.3 Peptides Other valuable substances that can be obtained from apricot kernels are bioactive peptides. A bioactive peptide is a specific protein fragment that has a positive impact on body functions and conditions and may eventually influence health (Diplock et al., 1999). Although these peptides can be found as independent molecules in foods, they are usually encrypted within the sequence of a precursor protein. In the latter case, they can be released through a proteolytic process. Different bioactive peptides from apricot kernels have been described, exhibiting antioxidant, angiotensinconverting enzyme (ACE)-inhibitory, or hypocholesterolemic activities (Garcı´a et al., 2016; Zhu et al., 2010; Gonza´lezGarcı´a et al., 2018). Garcı´a et al. (2016) prepared apricot kernel hydrolysates using different proteases as well as a simulated gastrointestinal digestion with pepsin and pancreatin and evaluated their different bioactivities. Despite simulated gastrointestinal digestion producing a hydrolysate with high antioxidant and ACE-inhibitory capacities, hydrolysates obtained with the other proteases showed even higher activities, especially the hydrolysates obtained with Alcalase and thermolysin enzymes. Indeed, the hydrolysate obtained with Alcalase showed the highest antioxidant capacity. On the other hand, the hydrolysate obtained with thermolysin showed the highest ACE inhibition (IC50 5 18.6 μg/mL) and the highest micellar cholesterol solubility inhibition (33% of inhibition). Zhu et al. (2010) also obtained hydrolysates with elevated ACE inhibition, highlighting the one obtained with Alcalase enzyme with an IC50 5 378 μg/mL. The study on the effect of the molecular weight of peptides on the activity of the hydrolysate concluded that the fraction of peptides with molecular masses lower than 1 kDa presented most of the activity of the hydrolysate with an IC50 5 150 μg/mL. In other work, Gonza´lez-Garcı´a et al. (2018) quantified four ACE-inhibitory peptides (Isoleucine-Tyrosine-Serine-ProlineHistidine (IYSPH), Isoleucine-Tyrosine-Threonine-Proline-Histidine (IYTPH), Isoleucine-Phenylalanine-Serine-ProlineArginine (IFSPR), and Valine-Alanine-Isoleucine-Proline (VAIP)) that had been previously described in different kernels from the Prunus genus. They observed that these peptides were also in apricot kernels in concentrations ranging from 13.2 to 607 μg/g depending on the peptide and genotype. Finally, Wang et al. (2010) optimized the conditions (hydrolysis time and temperature, enzyme-to-substrate ratio, and substrate concentration) for the hydrolysis of the apricot kernel with neutrase enzyme obtaining a hydrolysis degree of 34.1% and a peptide yield of 72.42%.

3.2.3

Essential oil

Essential oils are valuable natural products extracted from different aromatic plant organisms as fruits, fruit seeds, leaves, roots, flowers, or resins. They exhibit a huge range of applications in the food, cosmetic, or pharmaceutical fields, among many others (Khayyat and Roselin, 2018; Pateiro et al., 2018). In fact essential oils from different plants are commercially exploited (Rassem et al., 2016). They are composed of more than 200 volatile compounds. Alcohols, aldehydes, hydrocarbons, esters, phenols, or ketones are the main components of essential oils (Tavakolpour et al., 2017). These oils present numerous therapeutic effects such as antimicrobial, antiinflammatory, and antioxidant properties (Giacometti et al., 2018). Moreover, their capability to penetrate into the layers of the skin, due to their low size, facilitates their absorption and passage to the bloodstream. They have been used to treat diseases such as headaches, digestive disorders, or high blood pressure (Khayyat and Roselin, 2018). Traditional essential oil extraction methodologies are hydrodistillation, steam distillation, solvent extraction, or cold pressing, while more innovative extraction strategies are based on supercritical fluids, microwaves, or ultrasounds (Khayyat and Roselin, 2018). The use of innovative techniques enables the reduction of extraction times and improves the efficacy of the extraction (Tavakolpour et al., 2017). In the case of the apricot kernel, the most used strategy to extract the essential oil is hydrodistillation (see Table 3.3) (Lee et al., 2014; Li et al., 2016; Geng et al., 2016). The main advantages of this technique are its low cost, easiness, and scalability (Rassem et al., 2016). Hydrodistillation consists of oil distillation by boiling the apricot kernel in water for 1
3 h. Essential oil yield varies from 0.27% to 0.79%

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Valorization of Fruit Processing By-products

TABLE 3.3 Extraction methodology, yield, and composition of essential oil from apricot kernels. Extraction method

Oil yield

Composition

Ref.

Kernel air-drying and grinding (300 g), and hydrodistillation in 1.5 L water (clevenger type extractor, 3 h)

0.27% (w/w)

[Benzaldehyde] 5 90.6% [Mandelonitrile] 5 5.2% [Benzoic acid] 5 4.1%

Lee et al. (2014)

Powdered seed (200 g, 40-mesh) soaking in water (1 L, room temperature, 4 h), and hydrodistillation (clevenger extractor, 1 h)

0.79% (v/w)

[Benzaldehyde] 5 75.4% [Benzoic acid] 5 6.2% [Mandelonitrile] 5 5.4%

Li et al. (2016)

Removal of fatty oil, extractions of 100 mg press cake with 500 mL weak acid water (pH 5, 40 C, 1 h), hydrodistillation (1 h), separation of organic phase, and drying with anhydrous sodium sulfate

0.70%

[Benzaldehyde] 5 62.5% [Benzoic acid] 5 14.8% [Hexadecane] 5 4.0%

Geng et al. (2016)

depending on the apricot variety and the extraction procedure. In fact the powdering of the sample, its defatting, or its soaking in water results in higher oil yields (Lee et al., 2014; Li et al., 2016; Geng et al., 2016). Up to 21 different components have been identified within the apricot kernel essential oil, with benzaldehyde being the main constituent (62.5%
90.6%), followed by benzoic acid (4.1%
14.8%), mandelonitrile (5.2%
5.4%), and hexadecane (3.97%) (Lee et al., 2014; Li et al., 2016; Geng et al., 2016). Apricot kernel essential oil exhibits different bioactivities. Indeed it presents a certain degree of antimicrobial activity against some bacteria and yeasts, both through gaseous or direct contact with microorganisms. This behavior makes it a promising candidate to be used as an air disinfectant, preservative, or antimicrobial agent (Lee et al., 2014). Apricot essential oil has also been demonstrated to be a potent proapoptotic factor for human keratinocytes. Thereby it has a great potential in the treatment of psoriasis (Li et al., 2016). Finally, 1 mg/mL of this essential oil inhibited 44.8%
100% of 19 pathogenic fungi and exhibited low median effective concentrations (EC50) of 50.2
642.0 μg/mL. These results suggest that apricot essential oil could be useful in the development of botanical and agricultural fungicides (Geng et al., 2016).

3.3

Other apricot by-products

Although just a few works have been devoted to their study in the last decade (see Table 3.4), there are other byproducts generated by the apricot industry such as apricot pomace, thinned apricots, and the residues obtained after blanching or debittering apricot kernels.

3.3.1

Pomace

Apricot processing by the food industry to produce juices, drinks, and beverages generates by-products. The main byproduct, known as pomace, is mainly constituted by skins and pulp and thus presents a significant portion of the bioactive compounds. Polyphenols have been the bioactive compounds studied in the works devoted to this by-product (Dulf et al., 2017; Tabaraki et al., 2016) (see Table 3.4). Polyphenols extraction from the apricot pomace has been carried out by sonication with an alcohol/water mixture. Tabaraki et al. (2016) optimized the polyphenols extraction and obtained the best results with ethanol/water (70:30, v/v) and sonication at 35 C for 1 h. Dulf et al. (2017) opted for the utilization of HCl/methanol/water (1:80:19, v/v/v) and sonication at 40 C for 30 min. Significant differences were observed in the TPC obtained in both extracts that ranged from 19.3 to 120 mg gallic acid/100 g of sample. However, antioxidant capacity of both extracts, measured through the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay, was very high (70%
88%) (Dulf et al., 2017; Tabaraki et al., 2016). On the other hand, Dulf et al. studied the effect of the solid-state fermentation of the apricot pomace on the extraction and composition of phenolic compounds. For this purpose, two different filamentous fungi and five different fermentation times were tested. Results showed that TPC significantly increased from 120 to 150
200 mg gallic acid/ 100 g of pomace upon fermentation. Furthermore, total flavonoids content also increased. Moreover, individual phenolics concentrations decreased along with the fermentation time, except for quercetin-3-rutinoside which slightly

TABLE 3.4 Extraction method and characteristics of bioactive compounds obtained from kernel pomace, thinned apricots, and wastewaters obtained during apricot processing. By-product

Bioactive compound

Extraction of bioactive compounds

Content/composition

Ref.

Juice industry residuals

Phenolic compounds (TPC 5 19.3 mg gallic acid/100 g sample)

5 g sample 1 5 mL ethanol/water (70:30, v/v), sonication (35 C, 60 min), centrifugation, and concentration by evaporation at 40 C




Tabaraki et al. (2016)

Pomace

Phenolic compounds (TPC  120 mg gallic acid/100 g pomace)

2 g dried sample 1 3 3 20 mL HCl/methanol/ water (1:80:19, v/v/v), and ultrasonic bath (40 C, 30 min)

Total flavonoids  26 mg quercetin/100 g pomace Flavonols: [Quercetin-3-rutinoside] 5 16.5 mg/100 g [Quercetin-3(6vacetyl-glucoside)] 5 5.7 mg/100 g Cinnamic acids: [3-Caffeoylquinic acid] 5 7.8 mg/100 g [5-Caffeoylquinic acid] 5 15.1 mg/100 g

Dulf et al. (2017)

Pomace fermented by filamentous fungi

Phenolic compounds (TPC  150
200 mg gallic acid/ 100 g fermented pomace)

Thinned apricot

Phenolic compounds (TPC 5 932 mg gallic acid/100 g)

1 g freeze-dried sample 1 100 mL methanol/ water (80:20, v/v), homogenization by ultraturrax (30 s), and centrifugation. Repeat extraction

Total flavonoids 5 772 mg catechin/100 g [Flavan-3-ols] 5 304 mg/100 g dry weight: [Proanthocyanides] 5 304 mg/100 g dry weight) [Flavonols] 5 26 mg/100 g dry weight: [Quercetin-3-rutinoside] 5 23 mg/100 g dry weight [Hydroxycinnamic acids] 5 667 mg/100 g dry weight: [Chlorogenic acid] 5 434 mg/100 g dry weight [Neochlorogenic acid] 5 165 mg/100 g dry weight)

Redondo et al. (2017)

Blanching water concentrate (BWC)

Proteins, reducing sugars, polysaccharides, phenolic compounds, flavonoids, and amygdalin




[Proteins] 5 4.2 g/100 g [Reducing sugars] 5 4.6 g/100 g [Polysaccharides] 5 23.6 g/100 g [Phenolics] 5 1.4 g/100 g [Flavonoids] 5 2.5 g/100 g [Amygdalin] 5 33.5 g/100 g

Zhang et al. (2018)

Debittering water concentrate (DWC)

Proteins, reducing sugars, polysaccharides, phenolic compounds, flavonoids, and amygdalin




[Proteins] 5 10.3 g/100 g [Reducing sugars] 5 7.1 g/100 g [Polysaccharides] 5 14.3 g/100 g [Phenolics] 5 0.8 g/100 g [Flavonoids] 5 0.5 g/100 g [Amygdalin] 5 23.9 g/100 g

TPC, total phenolic content.

Total flavonoids  29
36 mg quercetin/100 g fermented pomace Flavonols: [Quercetin-3-rutinoside] 5 14.1
18.2 mg/100 g [Quercetin-3(6vacetyl-glucoside)] 5 4.1
5.2 mg/100 g Cinnamic acids: [3-Caffeoylquinic acid] 5 4.2
6.6 mg/100 g [5-Caffeoylquinic acid] 5 11.3
13.5 mg/100 g

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Valorization of Fruit Processing By-products

increased. Additionally, the fermented pomace extract exhibited higher DPPH inhibition (85%) than the extract obtained from the nonfermented pomace (70%).

3.3.2

Thinned apricots

When a fruit tree carries a heavy crop, fruits usually present small size and poor quality. The thinning of some fruits is a usual strategy to allow the rest of fruits to grow to a marketable size, as well as to remove injured, scarred, or misshapen fruits (Yoshikawa and Johnson, 1989). Thinned fruits can be directly sent to be dumped or incinerated, both causing environmental problems. However, fruits in early maturation stages present higher contents of phenolic compounds than ripe fruits (Manach et al., 2004). As shown in Table 3.4, just one work was devoted to the study of thinned apricots (Redondo et al., 2017). Polyphenols extraction was carried out employing a methanol/water mixture (80:20, v/v) and an ultraturrax homogenizer. Results showed a high TPC (932 mg gallic acid/100 g), much higher than that previously obtained in the fruit pomace or in the kernel oil (Dulf et al., 2017; Senica et al., 2017; Rai et al., 2013; Zhou et al., 2018; Tabaraki et al., 2016). Regarding polyphenols composition, all individual polyphenolic compounds presented higher concentrations in thinned apricots than in apricot pomaces or kernel oil, except flavonols that showed similar concentrations (Dulf et al., 2017; Senica et al., 2017). Consequently, the extract presented a high antioxidant capacity (DPPH scavenging 5 31.93 mg Trolox/g and ferric reducing antioxidant power (FRAP) 5 20.73 mg Trolox/g) (Redondo et al., 2017).

3.3.3

Blanching water concentrate and debittering water concentrate

A huge portion of apricot kernels are consumed as appetizers or added to different processed foods such as bakery products. However, the high concentration of amygdalin in apricot kernels makes necessary their prior blanching and debittering. The first step usually consists of the immersion of kernels in hot water (90 C
100 C) for a few minutes, followed by the manual or mechanical removal of the skin. The second step involves the soaking of peeled kernels in water at moderate temperature (30 C
70 C) for some hours or days (Zhang et al., 2018). These processes eliminate the amygdalin, but also produce the loss of proteins, fatty acids, polyphenols, or sugars. Moreover, the wastewaters from these processes are environmental pollutants and should not be directly discarded (Song et al., 2018). According to a survey carried out in different factories, these procedures resulted in a loss of up to 25% of the gross weight, specifically 70 kg of proteins, 100 kg of dietary fiber, 20 kg of amygdalin, and 5 kg of flavonoids per ton of apricot kernels. This wastewater, together with different medicinal herbs, has been used to prepare a cough syrup. However, in most cases these wastewaters are concentrated (blanching water concentrate (BWC) and the debittering water concentrate (DWC)) and these concentrates present high concentrations of valuable compounds (Zhang et al., 2018). Indeed, BWC is rich in polysaccharides, phenolic compounds, and amygdalin, while DWC shows high concentrations of proteins and reducing sugars. Furthermore, these concentrates have significant antioxidant properties as observed in Fig. 3.4. Both BWC and DWC showed a high reducing capacity, measured by the FRAP assay. The DPPH radical-scavenging capacities were high, with IC50 values of 4.24 and 14.77 mg/mL for BWC and DWC, respectively. The hydroxyl scavenging assay demonstrated that 2.4 mg/mL of BWC produces 60.9% inhibition, while 5.0 mg/mL of DWC inhibits 49%. These results enabled the conclusion that BWC was more antioxidative than DWC, which is consistent with its phenolics concentration.

3.4

Application of apricot by-products

Table 3.5 shows different applications of apricot by-products related either to the food or medical fields. Apricot kernel flour, obtained by the grinding of dried and peeled kernels, has been widely exploited (Eyidemir and Hayta, 2009; Seker et al., 2010; Dhen et al., 2017, 2018). This can be obtained from undersize or broken kernels and constitutes a cheap alternative to other ingredients. Eyidemir and Hayta (2009) evaluated the use of kernel flour as a substitute product of wheat flour in the preparation of noodles. They tested four different substitution levels (5%, 10%, 15%, and 20% flour weight basis) and observed that all of them resulted in noodles with higher contents of proteins, lipids, and ash than control noodles, while the noodles’ moisture decreased with the apricot kernel incorporation. Moreover, the authors studied the effect of the apricot flour incorporation on noodles’ color, cooking attributes, and sensory properties. They observed that the addition of apricot kernel flour at all levels affected all the characteristics and that they were acceptable up to a 15% flour weight basis.

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59

FIGURE 3.4 Antioxidant capacity of blanching water concentrate (BWC) and debittering water concentrate (DWC) evaluated through the measurement of (A) the reducing power, (B) the scavenging of DPPH free radical, and (C) the scavenging of OH free radical. Reproduced with permission from Zhang, Q., Wei, C., Fan, X., Shi, F., 2018. Chemical compositions and antioxidant capacity of by-products generated during the apricot kernels processing. CyTA-J. Food 16, 422
428.

Apricot kernel flour has been also applied to the preparation of cookies (Seker et al., 2010). In this case, the fat content in a cookie formulation was replaced by 10%, 20%, 30%, or 40% of apricot kernel flour. Results showed that the replacement of fat by apricot kernel flour did not affect the sensory properties of cookies and produced a considerably increase in fiber (up to a 12.86% fiber content with a 40% replacement). However, these conditions decreased the spread ratio and more than doubled the hardness. The study revealed that the best cookies were obtained when using a 10% or 20% of replacement, since they presented high fiber content and acceptable spread ratio, hardness, and sensory properties.

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Valorization of Fruit Processing By-products

TABLE 3.5 Applications of apricot by-products. Byproduct

Application

Preparation

Composition/characteristics

Ref.

Kernel flour

Preparation of noodles

Sieved kernel flour (1 mm) incorporation to noodles by replacing wheat flour (up to 15%)

Noodle: protein (11.5%), lipid (0.4%) Enriched noodle (15% apricot kernel): protein (13.5%), lipid (8.0%)

Eyidemir and Hayta (2009)

Kernel flour

Fat replacer in cookies

Kernels soaking in warm distilled water (1 h), removing of coat, drying, and grinding

Unmodified cookies: total dietary fiber (1.86%) Modified cookies: total dietary fiber (7.52%), decrease the spread ratio, and increase the hardness

Seker et al. (2010)

Replacing fat in cookies formulation (up to 20%) Kernel flour

Enrich wheat flour

Kernels soaking in distilled water (45 C, 1 h), removing of coat, sun-drying (40 C, 4 days), milling, and replacing wheat flour

Increase protein and fat and decrease carbohydrates and pasting properties

Dhen et al. (2017)

Kernel flour

Wheat-apricot kernel composite bread

Drying, peeling, and grinding of kernels

Wheat bread: protein (10.9 g/ 100 g), lipid (5.1 g/100 g), carbohydrates (52.0 g/100 g) Enriched bread (12% apricot kernel): protein (14.2 g/100 g), lipid (15.1 g/100 g), carbohydrates (39.5 g/100 g)

Dhen et al. (2018)

Replacing of wheat flour (up to 12%)

β-Galactosidase to produce free lactose cheese

Grounded kernel (100 g) 1 500 mL (0.02 M, pH 5), homogenization (4 C, 1 h), filtration, centrifugation, supernatant recovery, purification with ammonium sulfate (30%
70%), and dialysis against acetate buffer (0.02 M, pH 5, 4 C, 24 h)

β-Galactosidase specific activity 5 32.7 U/mg protein No significant changes in flavor, texture, and acceptability of free lactose cheese produced with β-galactosidase from apricot seeds and untreated cheese

Yossef and Beltagey (2014)

Probiotic ice creams

0.5% pomace (dietary fiber source) addition to probiotic ice creams before freezing

Improve survival of probiotic strains without adverse effects on ice cream properties

Ayar et al. (2017)

Kernel meal

Substitution of 30% of soybean meal in feed for rabbits (at the same time, substitution of 30% of corn meal by date rebus)

Dried kernels treatment with a hydraulic press and detoxification with 1% sodium bicarbonate

Nitrogen matter 5 47% Fiber 5 32% Reduce costs

Mennani et al. (2017)

Kernel

Kernel extract to treat dry eye disease

500 g dried and ground kernels were boiled in distilled water (100 C, 2 h) followed by extract condensation by freeze-drying

Extract yield 5 6.9% Topical administration of extracts improves dry eye symptoms (promote secretion of tear fluid and mucin)

Kim et al. (2016)

Kernel

Pomace

Dhen et al. (2017) prepared a wheat flour enriched with apricot kernel flour (4%
24%). The partial substitution of the wheat flour by the apricot kernel flour resulted in mixtures with increasing fat and protein contents and a reduced carbohydrate content. Moreover, this replacement affected the pasting, rheological, and swelling properties of the flour. Lately, these flour mixtures were successfully applied to the preparation of bread enriched in proteins and fat and with low carbohydrate content (Dhen et al., 2018). However, replacements higher than 12% were not recommended since they resulted in breads with lower volume, dark crust, and a hardened yellowish crumb.

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Apricot kernel has also been used to obtain β-galactosidase, also known as lactase (Yossef and Beltagey, 2014). This enzyme is usually utilized for the hydrolysis of lactose in the preparation of reduced or lactose-free products. The extraction of this compound from apricot kernels, its purification, and dialysis enabled the obtaining of an enzyme with a specific activity of 32.68 U/mg protein. It is known that β-galactosidase extracted from different microorganisms is inhibited by calcium found in dairy products. Unlike this, β-galactosidase extracted from apricot kernels improves the enzymatic activity with increasing calcium concentrations. Cheese prepared with apricot β-galactosidase showed no significant changes in comparison to untreated cheese related to the flavor, body texture, and overall acceptability. On the other hand, the apricot pomace released by the juice industry has been used for the preparation of probiotic ice creams (Ayar et al., 2017). Apricot pomace is a fiber-rich by-product that has a high dietary fiber content (72.3%). Its addition at a concentration of 0.5% to ice creams containing different microorganisms enhanced their survival rates up to 60 days at
20 C. Moreover, ice creams showed physicochemical and sensory properties comparable with conventional ice creams. Apricot by-products have been also utilized for animal feeding. In fact Mennani et al. (2017) studied the effect of adding apricot kernel meal along with date rebus into the diet of rabbits during the fattening phase. They replaced soybean meal by apricot meal and corn meal by date rebus at different rates (10%, 20%, and 30%). Results showed that this replacement did not affect rabbit growth rates, feed contribution, or slaughter yield. Conversely the chemical composition of rabbit meat was enhanced. Additionally, apricot by-products were used in therapeutic applications. Kim et al. (2016) observed that the extract obtained by boiling the kernels in water was effective for the treatment of dry eye disease. In fact the topical administration of the extract promoted the secretion of tears and mucin. The analysis of the extract showed that the major component was amygdalin, although they could not discover what compound was responsible for this effect. Finally, there are many patents that propose the use of apricot by-products for different applications. Some examples of the most recent patents are the incorporation of apricot by-products into beverages with metabolic and gut health benefits (Shin, 2017) or into beverages with enhanced nutrition and sensory attributes (Balasubramanian et al., 2014); the preparation of edible foodstuffs containing apricot pomace (Rizvi and Paraman, 2015) or apricot by-product slurries (Wenger and Wenger, 2014); the elaboration of a hairstyle-holding product containing apricot kernel oil (Carson, 2014); the preparation of a mixture to exfoliate skin and to treat acne based on crushed apricot kernels (Schwartz, 2010); and the construction of an apricot seed-based composite material (Koc, 2014).

3.5

Conclusions and future trends

Apricot by-products are a potential source of bioactive compounds. Kernels, the main apricot by-product, are a source of oil and are rich in unsaturated fatty acids, vitamin E active compounds, triterpenoids, carotenoids, phytosterols, and polyphenols. Obtaining apricot kernel oil by solvent extraction delivers high yields but the oil quality is low. Moreover, the use of high solvent volumes has a negative environmental impact. Unlike solvent extraction, mechanical expression is a more sustainable strategy but it results in lower extraction yields. The development of greener and more efficient strategies is a requirement for the extraction of oil from apricot kernels. Whole kernels and the apricot press cake are also sources of proteins and peptides with antioxidant, ACE-inhibitory, or hypocholesterolemic activities. Apricot kernels have been used to extract essential oil that is very appreciated by the pharmaceutical and cosmetic industries, due to its antimicrobial, antiinflammatory, and antioxidant properties. Its extraction from apricot kernel has been carried out by hydrodistillation, which is easy, cheap, and scalable. However, more innovative techniques are required in order to reduce extraction times and increase extraction yields. Other less exploited by-products, such as thinned apricots or wastewater concentrates, require deeper study for the better understanding of their potential. Finally, numerous applications of apricot by-products, mostly devoted to the development of foods with better functionalities and less cost, have been carried out.

Acknowledgments This work was supported by the Spanish Ministry of Economy and Competitiveness (Ref. AGL2016-79010-R) and the Comunidad of Madrid and European funding from FEDER program (S2013/ABI-3028, AVANSECAL-CM).

References Alpaslan, M., Hayta, M., 2006. Apricot kernel: physical and chemical properties. J. Am. Oil Chem. Soc. 83, 469
471.

62

Valorization of Fruit Processing By-products

Athar, M., Nasir, S.M., 2005. Taxonomic perspective of plant species yielding vegetable oils used in cosmetics and skin care products. Afr. J. Biotechnol. 4, 36
44. ¨ ztu¨rk, S., Yılmaz, S.O., 2017. Probiotic properties of ice creams produced with dietary fibres from by-products of the food Ayar, A., Sıc¸ramaz, H., O industry. Int. J. Dairy Technol. 71, 174
182. Bachheti, R.K., Rai, I., Joshi, A., Rana, V., 2012. Physico-chemical study of seed oil of Prunus armeniaca L. grown in Garhwal region (India) and its comparison with some conventional food oils. Int. Food Res. J. 19, 577
581. Balasubramanian, S., Hitchcock, B.W., Hsieh, M., Jordan, R.L., Mathews, J.D., Rivera, T., et al., 2014. Preparation and incorporation of co-products into beverages to enhance nutrition and sensory attributes. PCT Int. Appl. 53. WO 2014126806 A1 20140821. Barthet, V.J., Daun, J.K., 2004. Oil content analysis: myths and reality. In: Luthria, D. (Ed.), Oil Extraction and Analysis: Critical Issues and Competitive Studies. AOCS Press, Champaign, IL, pp. 100
117. Belˇscˇ ak-Cvitanovi´c, A., Durgo, K., Huðek, A., Baˇcun-Druˇzina, V., Komes, D., 2018. Overview of polyphenols and their properties. In: Galanakis, C. M. (Ed.), Polyphenols: Properties, Recovery, and Applications. Woodhead Publishing, United Kingdom, pp. 1
44. Bisht, T.S., Sharma, S.K., Sati, R.C., Rao, V.K., Yadav, V.K., Dixit, A.K., et al., 2015. Improvement of efficiency of oil extraction from wild apricot kernels by using enzymes. J. Food Sci. Technol. 52, 1543
1551. Buyukada, M., Aydogmus, E., 2018. Utilization of apricot seed in (co-) combustion of lignite coal blends: numeric optimization, empirical modeling and uncertainty estimation. Fuel 216, 190
198. Calpe-Berdiel, L., Escola-Gil, J.C., Blanco-Vaca, F., 2009. New insights into the molecular actions of plant sterols and stanols in cholesterol metabolism. Atherosclerosis 203, 18
31. Carson, J., 2014. Natural hairstyle holding product containing levan as a film-former. U.S. Pat. Appl. Publ., US 20140302101 A1 20141009, 6 pp. Chen, Z., Jiao, R., Ma, K.Y., 2008. Cholesterol-lowering nutraceuticals and functional foods. J. Agric. Food Chem. 56, 8761
8773. Connor, W.E., 2000. Importance of n-3 fatty acids in health and disease. Am. J. Clin. Nutr. 71, 171S
175S. Dhen, N., Ben Rejeb, I., Martinez, M.M., Roman, L., Gomez, M., Gargouri, M., 2017. Effect of apricot kernels flour on pasting properties, pastes rheology and gels texture of enriched wheat flour. Eur. Food Res. Technol. 243, 419
428. Dhen, N., Ben Rejeb, I., Boukhris, H., Damergi, C., Gargouri, M., 2018. Physicochemical and sensory properties of wheat—apricot kernels composite bread. LWT-Food Sci. Technol. 95, 262
267. Diplock, A.T., Aggett, P.J., Ashwell, M., Bornet, F., Fern, E.B., Roberfroid, M.B., 1999. Scientific concepts of functional foods in Europe consensus document. Br. J. Nutr. 81, S1
S27. Dulf, F.V., Vodnar, D.C., Dulf, E., Pintea, A., 2017. Phenolic compounds, flavonoids, lipids and antioxidant potential of apricot (Prunus armeniaca L.) pomace fermented by two filamentous fungal strains in solid state system. Chem. Cent. J. 11, 92. Durmaz, G., Alpaslan, M., 2007. Antioxidant properties of roasted apricot (Prunus armeniaca L.) kernel. Food Chem. 100, 1177
1181. Durmaz, G., Karabulut, I., Topcu, A., Asilturk, M., Kutlu, T., 2010. Roasting-related changes in oxidative stability and antioxidant capacity of apricot kernel oil. J. Am. Oil Chem. Soc. 87, 401
409. Eggersdorfer, M., Wyss, A., 2018. Carotenoids in human nutrition and health. Arch. Biochem. Biophys. 652, 18
26. El Din Yossef, H., El Dein El Beltagey, A., 2014. Extraction, purification and characterization of apricot seed β-galactosidase for producing free lactose cheese. J. Nutr. Food Sci. 4, 1
5. Eyidemir, E., Hayta, M., 2009. The effect of apricot kernel flour incorporation on the physicochemical and sensory properties of noodle. Afr. J. Biotechnol. 8, 85
90. FAOSTAT (Food and Agricultural Organization of the United Nations), 2018. Crops production data. ,http://www.fao.org/faostat/en/#data/QC. (accessed 09.18). Fadhil, A.B., 2017. Evaluation of apricot (Prunus armeniaca L.) seed kernel as a potential feedstock for the production of liquid bio-fuels and activated carbons. Energy Conv. Manag. 133, 307
317. Falk, J., Munne-Bosch, S., 2010. Tocochromanol functions in plants: antioxidation and beyond. J. Exp. Bot. 61, 1549
1566. Feist, P., Hummon, A.B., 2015. Proteomic challenges: sample preparation techniques for microgram-quantity protein analysis from biological samples. Int. J. Mol. Sci. 16, 3537
3563. Garcı´a, M.C., Gonza´lez-Garcı´a, E., Va´squez-Villanueva, R., Marina, M.L., 2016. Apricot and other seed stones: amygdalin content and the potential to obtain antioxidant, angiotensin I converting enzyme inhibitor and hypocholesterolemic peptides. Food Funct. 7, 4693
4701. Geciova, J., Bury, D., Jelen, P., 2002. Methods for disruption of microbial cells for potential use in the dairy industry
a review. Int. Dairy J. 12, 541
553. Geng, H., Yu, X., Lu, A., Cao, H., Zhou, B., Zhou, L., et al., 2016. Extraction, chemical composition, and antifungal activity of essential oil of bitter almond. Int. J. Mol. Sci. 17, 1421
1434. Gezer, I., Haciseferogullari, H., Demir, F., 2002. Some physical properties of Hacihaliloglu apricot pit and its kernel. J. Food Eng. 56, 49
57. Ghorab, H., Lammi, C., Arnoldi, A., Kabouche, Z., Aiello, G., 2018. Proteomic analysis of sweet algerian apricot kernels (Prunus armeniaca L.) by combinatorial peptide ligand libraries and LC-MS/MS. Food Chem. 239, 935
945. Giacometti, J., Kovacevic, D.B., Putnik, P., Gabric, D., Bilusic, T., Kresic, G., et al., 2018. Extraction of bioactive compounds and essential oils from mediterranean herbs by conventional and green innovative techniques: a review. Food Res. Int. 113, 245
262. Gonza´lez-Garcı´a, E., Maly, M., de la Mata, F.J., Go´mez, R., Marina, M.L., Garcı´a, M.C., 2016. Proof of concept of a “greener” protein purification/ enrichment method based on carboxylate-terminated carbosilane dendrimer-protein interactions. Anal. Bioanal. Chem. 408, 7679
7687. Gonza´lez-Garcı´a, E., Gutie´rrez Ulloa, C.E., de la Mata, F.J., Marina, M.L., Garcı´a, M.C., 2017. Sulfonate-terminated carbosilane dendron-coated nanotubes: a greener point of view in protein sample preparation. Anal. Bioanal. Chem. 409, 5337
5348.

Apricot Chapter | 3

63

Gonza´lez-Garcı´a, E., Garcı´a, M.C., Marina, M.L., 2018. Capillary liquid chromatography-ion trap-mass spectrometry methodology for the simultaneous quantification of four angiotensin-converting enzyme-inhibitory peptides in Prunus seed hydrolysates. J. Chromatogr. A 1540, 47
54. Go´rna´s, P., Miˇsina, I., Gravite, I., Soliven, A., Kaufmane, E., Seglina, D., 2015. Tocochromanols composition in kernels recovered from different apricot varieties: RP-HPLC/FLD and RP-UPLC-ESI/MSn study. Nat. Prod. Res. 29, 1222
1227. Go´rna´s, P., Radziejewska-Kubzdela, E., Miˇsina, I., Biega´nska-Marecik, R., Grygier, A., Rudzi´nska, M., 2017. Tocopherols, tocotrienols and carotenoids in kernel oils recovered from 15 apricot (Prunus armeniaca L.) genotypes. J. Am. Oil Chem. Soc. 94, 693
699. Gupta, A., Sharma, P.C., Tilakratne, B.M.K.S., Verma, A.K., 2012. Studies on physico-chemical characteristics and fatty acid composition of wild apricot (Prunus armeniaca Linn.) kernel oil, Indian. J. Nat. Prod. Resour. 3, 366
370. Han, X., Shen, T., Lou, H., 2007. Dietary polyphenols and their biological significance. Int. J. Mol. Sci. 8, 950
988. Han, Z., Liu, R., Cui, H., Zhang, Z., 2013. Microwave-assisted extraction and LC/MS analysis of phenolic antioxidants in sweet apricot (Prunus armeniaca L.) kernel skins. J. Liq. Chromatogr. Rel. Technol. 36, 2182
2195. Hassanien, M.M.M., Abdel-Razek, A.G., Rudzinska, M., Siger, A., Ratusz, K., Przybylski, R., 2014. Phytochemical contents and oxidative stability of oils from non-traditional sources. Eur. J. Lipid Sci. Technol. 116, 1563
1571. International Organization of Standarization (ISO), 1998. Oilseeds-determination of hexane extract (or light petroleum extract), called “oil content”. International Standard ISO 659, Geneva. Kenar, J.A., Moser, B.R., List, G.R., 2017. Naturally occurring fatty acids: source, chemistry, and uses. In: Ahmad, M. (Ed.), Fatty Acids: Chemistry, Synthesis, and Applications. Academic Press and AOCS Press, Libertyville, IL, pp. 23
82. Khayyat, S.A., Roselin, L.S., 2018. Recent progress in photochemical reaction on main components of some essential oils. J. Saudi Chem. Soc. 22, 855
875. Kim, C., Jo, K., Lee, I., Kim, J., 2016. Topical application of apricot kernel extract improves dry eye symptoms in a unilateral exorbital lacrimal gland excision mouse. Nutrients 8, 750
759. Koc, V., 2014. An apricot seed based composite material and related production method. PCT Int. Appl. 12. WO 2014149014 A1 20140925. Kukula-Koch, W., Baj, T., Sieniawska, E., Koch, W., Widelski, J., Luchowska, K., et al., 2015. Influence of extraction methods on the recovery of astragaloside IV from the roots of Astragalus mongholicus in Soxhlet- and Twisselmann-type apparatus. Open Chem. 13, 938
942. Lee, H., Ahn, J., Kwon, A., Lee, E.S., Kwak, J., Min, Y., 2014. Chemical composition and antimicrobial activity of the essential oil of apricot seed. Phytother. Res. 28, 1867
1872. Li, K., Yang, W., Li, Z., Jia, W., Li, J., Zhang, P., et al., 2016. Bitter apricot essential oil induces apoptosis of human HaCaT keratinocytes. Int. Immunopharmacol. 34, 189
198. Lozano-Grande, M.A., Gorinstein, S., Espitia-Rangel, E., Davila-Ortiz, G., Martı´nez-Ayala, A.L., 2018. Plant sources, extraction methods, and uses of squalene. Int. J. Agron. 2018, 1
13. Maguire, L.S., O’Sullivan, S.M., Galvin, K., O’Connor, T.P., O’Brien, N.M., 2004. Fatty acid profile, tocopherol, squalene and phytosterol content of walnuts, almonds, peanuts, hazelnuts and the macadamia nut. Int. J. Food Sci. Nutr. 55, 171
178. Manach, C., Scalbert, A., Morand, C., Remesy, C., Jime´nez, L., 2004. Polyphenols: food sources and bioavailability. Am. J. Clin. Nutr. 79, 727
747. Manzoor, M., Anwar, F., Ashraf, M., Alkharty, K.M., 2012. Physico-chemical characteristics of seed oils extracted from different apricot (Prunus armeniaca L.) varieties from Pakistan. Grasas Aceites 63, 193
201. ¨ zcan, M.M., 2009. Fatty acids and tocopherol contents of some Prunus spp. kernel oils. J. Food Lipids 16, 187
199. Mattha¨us, B., O ¨ zcan, M.M., 2015. Oil content, fatty acid composition and distributions of vitamin-E-active compounds of some fruit seed oils. Mattha¨us, B., O Antioxidants 4, 124
133. ¨ zcan, M.M., Al Juhaimi, F., 2015. Fatty acid composition and tocopherol content of the kernel oil from apricot varieties (Hasanbey, Mattha¨us, B., O Hacihaliloglu, Kabaasi and Soganci) collected at different harvest times. Eur. Food Res. Technol. 242, 221
226. Mennani, A., Arbouche, R., Arbouche, Y., Montaigne, E., Arbouche, F., Arbouche, H.S., 2017. Effects of incorporating agro-industrial by-products into diet of New Zealand rabbits: case of rebus of date and apricot kernel meal. Vet. World 10, 1456
1463. Monagas, M., Garrido, I., Lebro´n-Aguilar, R., Bartolome, B., Go´mez-Cordove´s, C., 2007. Almond (Prunus dulcis (Mill.) D.A. Webb) skins as a potential source of bioactive polyphenols. J. Agric. Food Chem. 55, 8498
8507. Moreau, R.A., Nystro¨m, L., Whitaker, B.D., Winkler-Moser, J.K., Baer, D.J., Gebauer, S.K., et al., 2018. Phytosterols and their derivatives: structural diversity, distribution, metabolism, analysis, and health-promoting uses. Prog. Lipid Res. 70, 35
61. Naziri, E., Mantzouridou, F., Tsimidou, M.Z., 2011. Squalene resources and uses point to the potential of biotechnology. Lipid Tech. 23, 270
273. Noke, A., Christiansen, T., Klo¨ck, G., 2013. Soxhlet or Twisselmann, an evidential report. Filtr. Sep. 33, 32
33. Orhan, I., Koca, U., Aslan, S., Kartal, M., Ku¨smenoglu, S., 2008. Fatty acid analysis of some Turkish apricot seed oils by GC and GC-MS techniques. Turk. J. Pharm. Sci. 5, 29
34. ¨ zcan, M.M., O ¨ zalp, C., U ¨ nver, A., Arslan, D., Dursun, N., 2010. Properties of apricot kernel and oils as fruit juice processing waste. Food Nutr. Sci. O 1, 31
37. Pandey, K.B., Rizvi, S.I., 2009. Plant polyphenols as dietary antioxidants in human health and disease. Oxidative Med. Cell. Longev. 2, 270
278. Pasquele, M.G.D., 2009. The essentials of essential fatty acids. J. Diet. Suppl. 6, 143
161. Pateiro, M., Barba, F.J., Dominguez, R., Sant’Ana, A.S., Khaneghah, A.M., Gavahian, M., et al., 2018. Essential oils as natural additives to prevent oxidation reactions in meat and meat products: a review. Food Res. Int. 113, 156
166. Pop, E.A., Diaconeasa, Z.M., Fetea, F., Bunea, A., Dulf, F., Pintea, A., et al., 2015. Carotenoids, tocopherols and antioxidant activity of lipophilic extracts from sea buckthorn berries (Hippophae rhamnoides), apricot pulp and apricot kernel (Prunus armeniaca). Bull. UASVM Food Sci. Technol. 72, 169
176.

64

Valorization of Fruit Processing By-products

Popa, V.M., Bele, C., Poiana, M.A., Dumbrava, D., Raba, D.N., Jianu, C., 2011. Evaluation of bioactive compounds and of antioxidant properties in some oils obtained from food industry by-products. Rom. Biotech. Lett. 16, 6234
6241. Rai, I., Bachheti, R.K., Joshi, A., Pandey, D.P., 2013. Physicochemical properties and elemental analysis of some non cultivated seed oils collected from Garhwal region, Uttarakhand (India). Int. J. ChemTech. Res. 5, 232
236. Raj, V., Jain, A., Chaudhary, J., 2012. Prunus armeniaca (apricot): an overview. J. Pharm. Res. 5, 3964
3966. Rassem, H.H.A., Nour, A.H., Yunus, R.M., 2016. Techniques for extraction of essential oils from plants: a review. Aust. J. Basic Appl. Sci. 10, 117
127. Redondo, D., Arias, E., Oria, R., Venturini, M.E., 2017. Thinned stone fruits are a source of polyphenols and antioxidant compounds. J. Sci. Food Agric. 97, 902
910. Rizvi, S.S.H., Paraman, I., 2015. Extrusion of agro-food industry byproducts and protein concentrates into value-added foods. U.S. Pat. Appl. Publ. US 20150282507 A1 20151008, 30 pp. Rudzi´nska, M., Go´rna´s, P., Raczyk, M., Soliven, A., 2017. Sterols and squalene in apricot (Prunus armeniaca L.) kernel oils: the variety as a key factor. Nat. Prod. Res. 31, 84
88. Salvo, A., La Torre, G.L., Rotondo, A., Mangano, V., Casale, K.E., Pellizzeri, V., et al., 2017. Determination of squalene in organic extra virgin olive oils (EVOOs) by UPLC/PDA using a single-step SPE sample preparation. Food Anal. Meth. 10, 1377
1385. Sayago, A., Marı´n, M.I., Aparicio, R., Morales, M.T., 2007. Vitamin E and vegetable oils. Grasas Aceites 58, 74
86. Schwartz, N., 2010. Compound for exfoliating skin and treating acne comprising clay substance. U.S. Pat. Appl. Publ., US 20100040701 A1 20100218, 3 pp. Seker, I.T., Ozboy-Ozbas, O., Gokbulut, I., Ozturk, S., Koksel, H., 2010. Utilization of apricot kernel flour as fat replacer in cookies. J. Food Process. Preserv. 34, 15
26. Senica, M., Stampar, F., Veberic, R., Mikulic-Petkovsek, M., 2017. Fruit seeds of the Rosaceae family: a waste, new life, or a danger to human health?. J. Agric. Food Chem. 65, 10621
10629. Sharma, P.C., Tilakratne, B.M.K.S., Gupta, A., 2010. Utilization of wild apricot kernel press cake for extraction of protein isolate. J. Food Sci. Technol. 47, 682
685. Shin, J., 2017. Preparation and incorporation of co-products into beverages to achieve metabolic and gut health benefits. U.S. Pat. Appl. Publ., US 20170119024 A1 20170504, 29 pp. Song, Y., Zhang, Q., Fan, X., Zhang, X., 2018. Effect of debitterizing treatment on the quality of the apricot kernels in the industrial processing. J. Food Process. Preserv. 42, e13556
e13563. Sostaric, T.D., Petrovic, M.S., Pastor, F.T., Loncarevic, D.R., Petrovic, J.T., Milojkovic, J., et al., 2018. Study of heavy metals biosorption on native and alkali-treated apricot shells and its application in wastewater treatment. J. Mol. Liq. 259, 340
349. Sriti, J., Talou, T., Faye, M., Vilarem, G., Marzouka, B., 2011. Oil extraction from coriander fruits by extrusion and comparison with solvent extraction processes. Ind. Crop. Prod. 33, 659
664. Srivastava, J.K., Gupta, S., 2006. Tocotrienol-rich fraction of palm oil induces cell cycle arrest and apoptosis selectively in human prostate cancer cells. Biochem. Biophys. Res. Commun. 346, 447
453. Tabaraki, R., Heidarizadi, E., Sadeghinezhad, N., Salimpour, S., Yosefi, Z., 2016. Recovery of natural antioxidants from fruit juice industry residuals by ultrasound-assisted extraction and response surface methodology. Acta Aliment. 45, 163
174. Tavakolpour, Y., Moosavi-Nasab, M., Niakousari, M., Haghighi-Manesh, S., Hashemi, S.M.B., Khaneghah, A.M., 2017. Comparison of four extraction methods for essential oil from Thymus daenensis subsp. Lancifolius and chemical analysis of extracted essential oil. J. Food Process. Preserv. 41, e13046
e13052. Torosyan, G., Matevosyan, G., Harutyunyan, S., 2011. Use of natural materials for wastewater treatment & improvement of water quality. In: Hlavinek, P., Winkler, I., Marsalek, J., Mahrikova, I. (Eds.), Advanced Water Supply and Wastewater Treatment: A Road to Safer Society and Environment, NATO Science for Peace and Security Series C: Environmental Security. Springer, Dordrecht, pp. 171
180. Torres-Duarte, A.P., Vanderhoek, J.Y., 2003. Conjugated linoleic acid exhibits stimulatory and inhibitory effects on prostanoid production in human endothelial cells and platelets. Biochim. Biophys. Acta-Mol. Cell Res. 1640, 69
76. Wang, C., Wang, Q., Tian, J., 2010. Optimization of enzymatic production of oligopeptides from apricot almonds meal with neutrase and N120P. Int. J. Mol. Sci. 11, 4952
4961. Wenger, L., Wenger, M.L., 2014. Production of engineered feed or food ingredients by extrusion. U.S. Pat. Appl. Publ., US 20140087044 A1 20140327, 15 pp. Weststrate, J., Meijer, G., 1998. Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesterolaemic and mildly hypercholesterolaemic subjects. Eur. J. Clin. Nutr. 52, 334
343. Willems, P., Kuipers, N.J.M., De Haan, A.B., 2008. Hydraulic pressing of oilseeds: experimental determination and modeling of yield and pressing rates. J. Food Eng. 89, 8
16. Wu, X., Gong, F., Wang, W., 2014. Protein extraction from plant tissues for 2DE and its application in proteomic analysis. Proteomics 14, 645
658. Yadav, A.K., Pal, A., Dubey, A.M., 2017. Experimental studies on utilization of Prunus armeniaca L. (wild apricot) biodiesel as an alternative fuel for CI engine. Waste Biomass Valoriz. 9, 1961
1969. Yildirim, F.A., Askin, M.A., 2010. Variability of amygdalin content in seeds of sweet and bitter apricot cultivars in Turkey. Afr. J. Biotechnol. 9, 6522
6524.

Apricot Chapter | 3

65

Yoshida, Y., Niki, E., Noguchi, N., 2003. Comparative study on the action of tocopherols and tocotrienols as antioxidant: chemical and physical effects. Chem. Phys. Lipids 123, 63
75. Yoshikawa, F.T., Johnson, R.S., 1989. Fruit thinning. In: LaRue, J.H., Jhonson, R.S. (Eds.), Peaches, Plums and Nectarines, Growing and Handling for Fresh Market. Division of Agriculture and Natural Resources, University of California, Oakland, CA, pp. 56
59. Zhang, Q., Wei, C., Fan, X., Shi, F., 2018. Chemical compositions and antioxidant capacity of by-products generated during the apricot kernels processing. CyTA-J. Food 16, 422
428. Zhou, B., Sun, Y., Li, J., Long, Q., Zhong, H., 2018. Effects of seed coat on oxidative stability and antioxidant activity of apricot (Prunus armeniaca L.) kernel oil at different roasting temperatures. J. Am. Oil Chem. Soc. 95, 1297
1306. Zhu, G., Duan, J., Zhao, H., Liu, M., Li, F., 2013. Apricot shell: a potential high-quality raw material for activated carbon. Adv. Mater. Res. 798
799, 3
7. Zhu, Z., Qiu, N., Yi, J., 2010. Production and characterization of angiotensin converting enzyme (ACE) inhibitory peptides from apricot (Prunus armeniaca L.) kernel protein hydrolysate. Eur. Food Res. Technol. 231, 13
19.

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Chapter 4

Avocado Huey Shi Lye1, Mei Kying Ong1, Lai Kuan Teh2, Chew Cheen Chang3 and Loo Keat Wei4 1

Department of Agricultural and Food Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia, 2Department of Biomedical

Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia, 3Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia, 4Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Kampar, Malaysia

Chapter Outline 4.1 4.2 4.3 4.4

Introduction Nutritional composition Extraction of phytochemicals Health benefits 4.4.1 Antioxidant effect 4.4.2 Anticancer 4.4.3 Antidiabetic

4.1

67 70 72 74 74 78 80

4.4.4 Antiatherogenic 4.4.5 Antimicrobial effect 4.4.6 Antiinflammatory effect 4.5 Industrial applications 4.6 Conclusion References Further reading

81 84 86 88 89 89 93

Introduction

With its exquisite nutritional profile, unique taste, and aroma, the avocado (AV) has been called “God’s greatest gift to humanity.” It has been reported that the consumption of AV started 12,000 years ago in Tehuaca´n city, Mexico, with the evidence of pristine AV trees planted along the “Oriental Sierra Madre.” Avocado originates from Central Mexico and has been dispersed to Guatemala, Central America, South America, and other parts of the world (Dorantes et al., 2004). The top 10 producers of AV, according to the Food and Agriculture Organization of the United Nations (Food and Agriculture Organization of the United Nations FAO, 1999), are shown in Fig. 4.1. This fruit has also been exported and consumed throughout the world (Fig. 4.2). Meanwhile, the largest importers of AV are listed in Fig. 4.3. The AV tree is a member of the eukaryote domain, Kingdom Plantae, Phylum Spermatophyte, Subphylum Angiospermae, Class Dicotyledonae, Order Laurales, Family Lauraceae, Genus Persea, and Species Persea americana (The IUCN Red List of Threatened SpeciesTM, 2017; Centre for Agriculture and Biosciences International, 2018). Alternatively, P. americana is also known as Laurus persea, Persea drimyfolia, Persea floccose, Persea gigantean, Persea leiogyna, Persea nubigena, Persea paucitriplinervia, and Persea steyermarkii (The IUCN Red List of Threatened SpeciesTM, 2017). Avocado also goes by a variety of different common names in different countries (Table 4.1). It is an evergreen, medium to large tree with an extremely shallow root system. Its canopy varies from symmetrically lower dense to asymmetrically upright. Leaves are alternately arranged with their shapes vary from oval, elliptic, to lanceolate, spanning 7
41 cm in length. Young leaves are reddish in color and transform to dark green, smooth, glossy, and leathery when mature. The AV tree is a dicotyledonous plant that blooms yellowish green flowers that has panicles 1
1.3 cm in diameter. It might also form inflorescence flowers that terminate in the shoots. Despite thousands of male and female flowers blooming for weeks and months to allow cross- and self-pollinations, only a low number of flowers are successfully fertilized into fruits (Centre for Agriculture and Biosciences International, 2018; Samson, 1991). The fruits are pear-shaped and covered by a yellowish green, purple, reddish, or almost black epidermis, with either shiny and smooth or bumpy brown
black surfaces. Additionally, the size of the edible buttery mesocarp that is attached to a large ovoid shaped seed increases as the fruit matures. Thereby an AV can weigh up to 2.3 kg, subjected to ecotypes (Centre for Agriculture and Biosciences International, 2018; Samson, 1991). Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00004-6 © 2020 Elsevier Inc. All rights reserved.

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FIGURE 4.1 Leading avocado producing countries in 2016. Data modified from FAOSTAT (2018).

FIGURE 4.2 Top 10 avocado exporters in the world in 2013. Data modified from FAOSTAT (2018).

There are three ecotypes of AV, P. americana var. drymifolia (Mexican ecotype), P. americana var. guatemalensis (Guatemalan ecotype), and P. americana var. americana (West Indian ecotype) (Samson, 1991). Although Mexican and Guatemalan ecotypes are native to highlands, they are best adapted to subtropical and tropical habitats, respectively. The West Indian ecotype that originates in the lowlands tends to be adapted to a semitropical habitat (Dorantes et al., 2004). The Mexican ecotype is often surrounded with a green membrane-like peel; the West Indian ecotype is shielded with smooth and leathery to glossy skin; whereas the Guatemalan ecotype is covered with thick corky skin. The fruit shapes vary from asymmetrical, spherical to pyriform. The examples of Mexican cultivars are P. drimyfolia, Bacon,

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FIGURE 4.3 Main importers of avocado in 2013. Data modified from FAOSTAT (2018).

TABLE 4.1 Avocado in different languages or recognizes by different countries. Languages/countries

Name of avocado

Brazil

Abacatte-do-mato, pau-andrade, canela-rosa, canela-mac¸aranduba, canela-ruiva, mac¸aranduba, canela-vermelha, mac¸aranduba-falsa Abacateiro Advokaat Alligator pear and butter fruit Avocado Avocado and apukado Avocadobirne and alligatorbirne Avocat, avocatier, zaboka and zabelbok Avocatoboom Avokaa Avoˆkaa Avokad and adpukat Awokado Bata Kyese, htaw bat Leˆ daˆu` Mafuta, mpea, mwembe and mparachichi Pagua and aguacate Palta Zaboka

Portugese Dutch Indian Amharic, Filipino and Mandinka Malays German French Netherlands Cambodia Khmer Indonesian Thais Pidgin English Burmese Vietnamese Swahili Spanish Chile, Ecuador, Peru Creol

Source: Data were compiled from the Centre for Agriculture and Biosciences International, 2018. Persea americana (avocado). Invasive Species Compendium. Available from: ,https://www.cabi.org/isc/datasheet/39380..

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Valorization of Fruit Processing By-products

Collinson, Ettinger, Hall, Gottifried, Hickson, Mayapa´n, Pernod, Sharwil, Topa-topa, and Zutano (Dorantes et al., 2004; Food and Agriculture Organization of the United Nations FAO, 1999). On the other hand, West Indian cultivars are Persea gratissima, Datton, Donnie, Gaertn, Grothfry, Murashige, Nabal, Pollock, Puebla, Sharwil, Simmonds and Winslowson. Moreover, Guatemalan cultivars that have been widely recognized are Anaheim, Gwen, Hass, Linda, MacArthur, Nabal, Orotava, Pinkerton, Reed and Taylor (Dorantes et al., 2004). These ecotypes of AV are categorized based on their physiological and storage characteristics. The physiological characteristics are oil content, fruit size, climatic adaptation, volume of rainfall, flavor, peel texture, and time to maturity. Tolerance toward cold and diseases are also one of the factors to categorize AV (Samson, 1991). The oil content of an AV is highly dependent on its fruit size, adaptation to volume of rainfall, and resistance to various degrees of temperature. The average fruit weights for Mexican, Guatemalan, and West Indian ecotypes are 75
300, 300
400, and 500
600 g, respectively. The Mexican ecotype with smaller size fruits yields the highest oil content, which is 30% of its fresh weight. The Guatemalan ecotype is an intermediate size of fruit with nutty flavored pulp that yields an intermediate oil content. The larger fruit size of the West Indian ecotype yields relatively lower oil content (Dorantes et al., 2004). These three ecotypes can withstand 200
2500 mm average annual rainfall, in a readily drained and aerated soil with pH 5
5.8 (Centre for Agriculture and Biosciences International, 2018). The Mexican ecotype shows the best resistance to low temperature down to 26 C. Meanwhile, the Guatemalan and West Indian ecotypes can resist down to 24 C and 22 C, respectively (Duarte et al., 2016). However, the qualities of AV may also be affected when they are exposed to abiotic and biotic stresses. Salinity, irradiance, water stress, and temperature are factors of abiotic stress. It has been reported that the root system of the AV tree is intolerant to anaerobic surroundings, and the root becomes mildewed after being exposed to a day of waterlogging. Biotic stresses of AV plant are the result of damage done by insect pests such as the AV looper, the coconut bug AV red mites, and the false codling moth, as well as the fruit fly. Pathogens such as Ewinia carotovora, Phomopsis perseae, Stilbella cinnabarina, and Lasiodiplodia theobromae are known to cause stem-end rot disease. Furthermore, Colletotrichum gloeosportoides is the causative agent for anthracnose disease among AV plants (Centre for Agriculture and Biosciences International, 2018). Nonetheless, somatic embryogenesis has been widely applied to enhance the biotic resistance of AV. For example, the transient expression of uidA reporter gene is induced to regenerate AV plants via in vitro approach (Ahmed et al., 1998). The uidA reporter gene also ligates to the nptII gene in a construct prior to performing Agrobacterium tumefaciens infection to obtain transgenic somatic embryos of AV (Cruz-Herna´ndez et al., 1998). Alternatively, a construct coded with antifungal defensin gene PDF1.2 is transferred into the embryogenic Hass cultivar to enhance the defense mechanism against anthracnose infection (Raharjo et al., 2008). When ligating PDF1.2 gene, uidA reporter gene, and bar gene in a binary vector pGPTV, this construct exerts resistance to phosphinothricin, which is an active ingredient of the herbicide Finale (Raharjo et al., 2008). When an AV embryogenic culture is transformed with a construct containing pPZP200 and pAG4092 binary vectors together with a bacteriophage S-adenosyl-l-methionine gene, an extended shelf life has been observed (Alfaro and Litz, 2007). Fruit ripening of AV can be controlled by transforming Phytophthora cinnamomi, C. gloeosporioides and AV sunblotch viroid into the cultivar, as exampled in the West Indian ecotype (Pagliaccia et al., 2013; Kimaru et al., 2018).

4.2

Nutritional composition

Avocado is a functional food that consists of 65%
75% of flesh with a nutritious content that varies among the cultivars. An edible portion of AV comprises 73.23% water, 14.66% lipids, 8.53% carbohydrates (glucose, sucrose and fructose), and 2% proteins (Table 4.2). It also contains a distinct amount of organic acids, such as 0.32% malic acid, 0.05% citric acid, and 0.03% oxalic acid. The total number of calories of a half AV is 109 kcal (United States Department of Agriculture USDA, 2018). The four categories of lipids identified from an AV are neutral lipids, glycolipids, phospholipids, and free fatty acids. Neutral lipids are the triglycerols, accounting for 96% of the total lipids in AV. Examples of triglycerols are linoleyl diolein, dioleyl palmitin, linoleyl oleyl palmitin, dioleypalmitolein, and triolein. The major fatty acids found in an AV are octadecenoic acid (18:0), palmitoleic acid (16:1), oleic acid (18:1), and octadecadienoic acid (18:2), in the relative lipid contents of 7%
22%, 3%
11%, 59%
81%, and 7%
14%, respectively. A high amount of oleic acid is able to decrease the magnitude of inflammation while preventing breast cancer (Li et al., 2014), diabetes (Palomer et al., 2017), and cardiovascular disease (CVD) (Hioki et al., 2016). The flesh with an abundance of oleic acid can also lead to an easily digestible texture. Therefore it can be used to replace olive oil in cooking and dressing (Carvalho et al., 2015). This easily digestible flesh with a creamy and smooth texture as well as a rich flavor and

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71

TABLE 4.2 Nutritional composition of an avocado fruit. Nutritional composition Water (%) Protein (%) Total lipid (%) Carbohydrate (%) Fiber (%) Ash (%)

Amounta 73.230 2.000 14.660 8.530 6.700 1.580

Minerals (mg/100 g) Potassium, K Phosphorus, P Magnesium, Mg Calcium, Ca Sodium, Na Zinc, Zn Iron, Fe

485.000 52.000 29.000 12.000 7.000 0.640 0.550

Vitamins (mg/100 g) Choline Ascorbic acid Alpha-tocopherol Niacin, B3 Panthothenic acid, B5 Pyridoxine, B6 Riboflavin, B2 Folate, B9 Thiamin, B1 Phylloquinone Biotin (B7)

14.200 10.000 2.070 1.738 1.390 0.257 0.130 0.081 0.067 0.021 0.006

Carotenoids (mg/100 g) Lutein 1 zeaxanthin β-Carotene β-Criptoxanthin α-Carotene

0.271 0.062 0.028 0.024

Lipids (g/100 g) Monounsaturated fatty acids Saturated fatty acids Polyunsaturated fatty acids

9.799 2.126 1.816

a

Data based on 14% Florida and 86% California ecotypes.

supreme nutritional content is also recommended as a puree for infants (Centre for Agriculture and Biosciences International, 2018). Moreover, the ratio of polyunsaturated fatty acids to saturated fatty acids (P/S) for AV is 0.74. A high P/S ratio is found to decrease low-density lipoprotein (LDL) levels while maintaining high-density lipoprotein (HDL) levels (Peou et al., 2016). Thus it is believed that supplementing AV in the diet or substituting AV for butter and margarine might help to improve lipid profiles. This is because high polyunsaturated fatty acids content in AV promotes endothelium vasodilation and antioxidant capacity. Meanwhile, the risks of metabolic syndrome, myocardial infarction, and insulin resistance are reduced upon consumption of AV (Panchal et al., 2018). Hence the Panchal et al. (2018) has made a recommendation to incorporate AV in the diet and to replace meat derivatives with AV pulp. This association also promotes the Mediterranean diet, which contains AV, as the predominant diet among CVD and ischemic stroke patients (Steffel et al., 2018). Furthermore, the consumption of AV was thought to contribute to weight loss, for example, diet supplemented with AV might accelerate basal metabolism rate in human (Fulgoni et al., 2013). However, an energy restricted diet study involving 55 subjects concluded that daily consumption of 200 g AV neither decreases the weight

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Valorization of Fruit Processing By-products

nor reduces serum lipid levels (Pieterse, 2003). Despite its contribution to weight loss still being debatable, it is undeniable that AV contains a high amount of beneficial lipids. In addition, an AV is also rich in insoluble and soluble fibers, minerals, and vitamins. Several vitamins, including provitamin A, vitamin E, and vitamin C, serve as antioxidants that decrease the amounts of free radicals and reactive oxygen species (Dreher and Davenport, 2013). Examples of free radicals are hydroxyl radicals, hydrogen peroxide, nitric oxide radical, superoxide anion, peroxynitrite radical, hypochlorite, and oxygen singlet. Overwhelmed free radicals can destroy essential macromolecules which can deregulate cells’ homeostatic ability, cause lipid peroxidation, and enhance oxidative stress (Au et al., 2015). Extreme oxidative stress leads to inflammation, aging, CVDs, and ischemic stroke (Lye et al., 2018; Wei et al., 2015). Being a powerful antioxidant, vitamin E conspires with vitamin C to counteract oxidative stress by scavenging the aforementioned free radicals (Dreher and Davenport, 2013). High concentrations of persenones A and B obtained from AV mesocarp can inhibit free radical generation and suppress inflammation (Kim et al., 2000a). Nonetheless, the high amount of vitamin B6 (pyridoxine) present in the fruit is able to reduce the risk of ischemic stroke. This is due to the fact that pyridoxine serves as the cofactor for homocysteine and converts homocysteine to cysteine in the one-carbon metabolism. The high amount of pyridoxine in the fruit prevents hyperhomocysteinemia, which is the risk factor for ischemic stroke (Keat Wei et al., 2015). To a lesser extent, the AV fruit also contains a high amount of vitamin B9 or folic acid, which is pertinent for embryo development. The consumption of adequate folic acid is important for women at child-bearing age in order to prevent having a baby with neural tube defects (Loo and Gan, 2012). Other than vitamins, AV fruit also contains high amounts of potassium and chlorophyll. Potassium, a source of glutathione, is an essential mineral that regulates muscle activity and blood pressure. It is also able to reduce susceptible risks of ischemic stroke to a maximum of 40% (Iso et al., 1999). When moving inward from skin to the seed, the green-skinned AV contains the highest amount of chlorophyll (D186 μg/g FW), followed by dark green flesh (D38 μg/ g FW) and yellow flesh (D2.2 μg/g FW). It has been reported that pheophytins a as well as chlorophylls a and b have been identified in the oil, flesh, and skin of AV. These chlorophyllides a and b are associated with reduced risk of cancers (Ashton et al., 2006). Nevertheless, other phenolic compounds isolated from AV include (2)-epigallocatechin3-gallate, (2)-epicatechin, and cyanidin (United States Department of Agriculture USDA, 2018).

4.3

Extraction of phytochemicals

The main industrialized products from AV are its oil and guacamole (Rodrı´guez-Carpena et al., 2011b). The manufacturing procedures of AV oil from AV fruit have produced a huge amount of by-products such as peel and seed. However, these by-products are usually discarded at the industrial level. Nowadays much existing literature has described the great potential of the health benefits of the AV peels and seeds and these are elaborated more in the subsequent sections. There are several common methods of AV fruit extraction, comprising conventional and contemporary extraction techniques. The conventional extraction techniques normally use physical and solvent procedures. Methanol and acetone are the commonly used solvents for the extraction of AV oil. One of the examples of the contemporary extraction technique is accelerated solvent extraction (ASE). It is a solid
liquid extraction process conducted at high pressures of 10
15 MPa and high temperatures of 50 C
200 C. This method has advantages over traditional extraction methods due to the huge reduction in the amount of extraction time and solvents used. This method uses water, ethanol, or their mixtures which are generally recognized as safe (GRAS) solvents for the extraction of phytochemical compounds. Meanwhile, ASE produces a higher yield compared to other traditional methods (Sun et al., 2012). Basically there are three different conventional extraction methods of AV oil: aqueous, pressing, and solvent extractions. Water or aqueous extraction is the most traditional process to recover oil from plant sources. The enzymatic or mechanical destruction of tissue cells containing lipids is followed by centrifugation to separate the oil from the oil
water emulsion. Aqueous separation methods are further classified into three groups depending on the cell walls destruction method and the driving force of the oil layer separation. These three aqueous methods are enzymatically assisted centrifugation separation, mechanically assisted centrifugation separation, and mechanically assisted hot-water separation methods, as shown in Fig. 4.4. The aqueous separation technique has many advantages compared to the solvent and pressing extraction processes. The operation of aqueous extraction is very practical with its simple process and low cost because it does not require a large removal of water volume from fresh pulp. Extraction yield from AV paste was reported to be improved more than 25-fold by enzymatically assisted centrifugation compared with nonenzymeassisted centrifugation (Buenrostro and Lo´pez-Munguia, 1986). The types of endogenous enzymes used are pectinases,

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73

Method of extraction of avocado oil

Contemporary/modern

Conventional

Extraction based on organic solvent

Aqueous extraction

Pressurized liquid extraction

Extraction assisted by ultrasonic bath

Extraction based on maceration/ pressing

Mechanically assisted hot water separation

Supercritical carbon dioxide (SC-CO2)

Accelerated solid–liquid extraction (ASE) Enzymatically assisted centrifugation separation

Coldpressed avocado oil (CPAO)

Mechanically assisted centrifugation separation

FIGURE 4.4 Conventional and contemporary extraction method for avocado oil.

celluloses, pectolytic enzyme, proteases, and α-amylase. These enzymes hydrolyze the cell walls and ease the oil release from the cells. Important factors affecting the extraction yield should be considered, such as enzyme type and concentration, temperature of enzyme reaction, and dilution ratio of paste to water. Oil droplets in the cells in AV pulp are ruptured and released by mechanical force through the mechanically assisted centrifugation method. In this technique the most important factors to ensure high oil yield are the particle size of the ruptured cells, heating temperature, centrifugal force, pulp, and electrolyte concentration. It has been reported that oil recovery was higher (71.45%) at pH 5.5 than at pH 4.0 (65.77%) (Bizimana et al., 1993). This is because appropriate pH and heating are crucial factors to prevent or reduce oil emulsification. Oil emulsification can result in difficult oil separation from the mixture during centrifugation. Inorganic salts such as NaCl, CaSO4, and CaSO3 can be added to the slurries in order to promote separation of oil from water. The fine-ground slurries can be further diluted or heated with hot water in the hot-water separation method. These processes will ease the release of oil from the slurries and inactivate the lipolytic enzymes. These lipolytic enzymes can cause oil hydrolysis and oxidation that lead to the deterioration of quality of the crude AV oil. The temperatures of hot water used are usually from 100 C to 105 C to separate oil parts. Hamzah (2013) reported that homogenization pressures from 7 to 71 kg/cm2 prior to heating are recommended to be employed in order to break down the emulsion easily. Pressing technology is another common method used to extract oil from oilseed material, which contains relatively high oil content. Oil is extracted by the physical action of pressing or squeezing oily materials with a screw or hydraulic press. From the perspective of physicochemical properties, AV fruit contains higher moisture content, about 77%, than other oilseeds. This high water content of fruit pulp can affect the oil yield and quality. Several pretreatment methods, such as drying, slicing of AV flesh, application of solid additives, and microwave-oven drying of AV pulp, are highly recommended prior to processing. After pressing, a drying process will be carried out to dry fruit slices to 4% or 5% water content (Qin and Zhong, 2016). Sun-drying and oven-drying are the common traditional drying methods used to dry the fruit slices. However, these methods have setbacks because they are time-consuming and give poor oil quality. Therefore microwave oven-drying technique is well-accepted because it shortens time and also assists in disrupting the cell walls and structures. The oil-squeezing effect is reported to be improved if the solid additives are nontoxic, insoluble in water or oil, and have a certain level of granularity and hardness. After the squeezing and mixing process, moderate heating increases the cell wall disruption during the extrusion process and subsequently increases the yield of the AV oil extraction. Moreover, a moderate heating process induces lipase inactivation to prevent or reduce the hydrolysis of AV oil during oil storage period. Traditional organic solvent extraction using hexane and acetone is also widely used to separate oil from various oily sources. The first step of solvent extraction usually involves the immersion of sliced, dried, and ground AV fruit in an organic solvent. Extraction yield by hexane and acetone was 54% and 12%, respectively (Moreno et al., 2003).

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Valorization of Fruit Processing By-products

This extraction method using an appropriate solvent can produce a higher yield of oil, but in the long-term this method can cause environmental pollution and leave solvent residues in the end products that degrade the quality of the AV oil. Besides the aqueous pressing and solvent separations, supercritical fluid extraction, also known as supercritical carbon dioxide (SC-CO2), is a new green solvent technique used in AV oil extraction. This new technique is biologically safer without leaving any solvent residues in the end product. Furthermore, suitable SC-CO2 solubility to produce certain desired lipid soluble products can be controlled to manipulate the pressure and temperature of the operation process. Another benefit of using the SC-CO2 extraction method is that chlorophyll or unsaponifiable compounds can be removed from AV oil which gives a better quality of AV oil. This extraction is more selective than that by the solvent extraction method, and thus gives a lower extraction yield and serves as a purification process for the industrial extraction of AV oil (Qin and Zhong, 2016). There are several factors that affect the extractability and quality of AV oil, such as fruit ripeness, pulp moisture, and drying method. Ripe AV fruit will produce hydrolytic enzymes such as cellulases and polygalacturonases, which cause degradation of parenchyma cell walls, for the ease of the solvent to extract oil from the parenchyma cells. Therefore it is reported that both SC-CO2 and hexane extraction methods produce average yields of 626 and 713.5 g/kg from oven- and freeze-dried ripe AV mesocarp, respectively, higher than the yields from unripe fruit. The reduction of pulp moisture is important prior to solvent extraction because high pulp moisture interferes with the oil extraction effect. The oil extraction yield from freeze-dried ripe AV extracted with SC-CO2 was significantly higher than from oven-dried ripe AV (Mostert et al., 2007). The freeze-drying method can produce more brittle and powdery dried material, while oven-dried material has a harder structure caused by starch gelatinization and protein denaturation. These incidences will act as physical barriers surrounding the oil cells and causing solvent transport resistance to the cellular surface. Apart from oil extraction yield and quality, it is also essential to consider the chemical composition of end products before proposing any suitable extraction method. Microwave-assisted squeezing and microwave-assisted hexane extractions showed lower peroxide values and free fatty acids contents of the extracts compared to hexane or acetone extraction. Differences in fatty acid profiles, especially for linolenic cis, linoleic cis, palmitic, oleic cis, and palmitoleic cis acids were found in oil extracted with different extraction methods. This reflected the different solubilities of fatty acids in the solvent used. Among the five types of extraction methods mentioned earlier, the SC-CO2 method provided a wider range for fatty acid profile determination (Reddy et al., 2012) and gave the lowest content of oxidizing metals, such as copper and iron.

4.4

Health benefits

Different parts of the AV have been used as a complementary medical option, especially to improve metabolic syndrome (MetS), as they are regarded as natural and safe. It has also been broadly claimed that AV can improve various components of MetS including obesity, hyperglycemia, hypertension, and dyslipidemia (Fig. 4.5). All these various components could be correlated with an increased risk of developing CVDs and type 2 diabetes mellitus which are found to be an increasing cause of morbidity and mortality in both developed and developing countries (Fulgoni et al., 2013; Tabeshpour et al., 2017).

4.4.1

Antioxidant effect

Free radicals may affect human health by inducing oxidative stress that leads to serious damage to important biomacromolecules and subsequently cell death plus organ dysfunction (Rotta et al., 2016). These antioxidants can counteract with the presence of free radicals such as superoxide (), hydroxyl (OH ), and peroxyl (ROO ). Several isolated and identified antioxidant compounds from AV are shown in Table 4.3. However, the potential of antioxidants is found to be greatly dependent on the AV varieties and the types of extracting solvents, affecting the total phenolic content (TPC) and total flavonoid content (TFC) (Rodrı´guez-Carpena et al., 2011a; Antasionasti et al., 2017; Wang et al., 2010). The antioxidant activity of extracts are normally evaluated using oxygen radical absorbance capacity (ORAC), 1,1,diphenyl-2-picrylhydrazyl (DPPH) assays, 2,2ʹ-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) cation radical scavenging, ferric reducing antioxidant power (FRAP) assays, trolox equivalent antioxidant capacity (TEAC), and cupric ion reducing antioxidant capacity (CUPRAC) (Huang et al., 2005; Ding et al., 2007; Rodrı´guez-Carpena et al., 2011a). G

G

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Avocado (Persea americana) Fuerte Medium to large with an elongated pyriform (pear) shape; lower percentage of pulp

Shepard (available in Australia) Green-skinned with butterfly yellow flesh Hass Dark green-colored skinned, bumpy skin and with better ratio of edible portion

(1) Seed

(3) Peel

(2) Pulp

Improved the risk factor of metabolic syndromes (a–c) (a) High blood glucose (Hyperglycemia)

(b) Dyslipidemia [High density lipoprotein cholesterol (HDL) < 1.0 mmol/L (male); 1.7 mmol/L]

(Fasting blood glucose > 6.1 mmol/L)

(c) Obesity (Waist circumference > 102 cm (male); >88 cm (female)

Able to prevent: Type 2 diabetes mellitus

Cardiovascular diseases

FIGURE 4.5 Avocado improves various components of metabolic syndrome.

TABLE 4.3 Antioxidant compounds of avocado. Extract

Bioactive compound

Seed

References Ding et al. (2007)

OH OH OH OH HO HO

O

O OH OH OH

Peel: Shepard and Hass

O

OH

(+)-catechin

(-)-epicatechin ´ Kosinska et al. (2012)

OH

O OH OH HO

O OH OH

3-O-caffeoylquinic acid (Continued )

75

76

Valorization of Fruit Processing By-products

TABLE 4.3 (Continued) Extract

Bioactive compound

Pulp

References Rodrı´guez-Sa´nchez et al. (2013)

CH3 CH2

O

O

OH

CH3

O

Persediene CH3

O

O

O

OH

CH3

Persenone-A CH3

O

O

CH3

OH

O

Persenone-B CH3

O

O

OH

CH3 O CH3

O

Persenone-C

O

CH3

Persin O

OH

CH2

O

O

OH

OH

1-acetoxy-2,4-dihydroxy-n-heptadeca-16-ene

CH3 O

CH3

O OH

OH

1-acetoxy-2,4-dihydroxy-heneicosa-12,15-diene Seed pulp and peel

Ajani and Olanrewaju (2014)

OH O

Syringic acid H3C

O

O

CH3

OH

OH

OH O OH HO

Epigallocatechin

OH OH

Peel

OH

Antasionasti et al. (2017)

OH

HO

CH2

1,2,4-trihydroxyheptadec-12,16-diene

4.4.1.1 Pulp Due to less attention being paid toon the antioxidant activity of the AV fruit, the antioxidant capacities of lipophilic and hydrophilic phytochemicals at different ripening stages (RSs) over 12 days were studied by Villa-Rodrı´guez et al. (2011). The RSs were denoted as RS1, RS2, RS3, and RS4 which each indicated a 4-day interval. The authors found that total phenols were increased throughout the RSs. Among the RSs studied, the highest antioxidant capacity was found at RS2 for lipophilic extract of Hass AV fruit with 0.0934 g/mL, 8996.34 μmol TE/g FW, and 893.02 μmol TE/g FW for DPPH, TEAC, and ORAC assays, respectively. In contrast, hydrophilic extracts of Hass AV fruit at RS3 stage

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77

were found to possess the greatest antioxidant capacity with 0.3876 g/mL, 3102.32 μmol TE/g FW, and 281.46 μM TE/ g FW for DPPH, TEAC, and ORAC assays, respectively. This result showed that the antioxidant capacity values of hydrophilic extracts were lowered than lipophilic extracts which may be due to the low hydrophilic phytochemical constituents and their antagonist effects. This was supported by Rodrı´guez-Sa´nchez et al. (2013), where lipophilic extract of AV pulp showed a significant higher (P , .05) antioxidant capacity than the hydrophilic extract. The acetogenins present were identified as novel lipophilic antioxidants that present in AV pulp. The antioxidant compounds were 1-acetoxy-2,4-dihydroxy-n-heptadeca-16-ene, persediene, persenone-C, persenone-A, persenone-B, persin, and 1acetoxy-2,4-dihydroxy-heneicosa-12,15-diene. A team of researchers led by Vinha et al. (2013) in Portugal, studied the physicochemical parameters, phytochemical contents, and nutritional properties of Algarvian AV of Hass variety. The bioactive compounds evaluated were phenolics (410.2 6 69.0 mg/100 g), ascorbic acid (4.1 6 2.7 mg/100 g), carotenoids (0.815 6 0.201 mg/100 g), vitamin E (5.36 6 1.77 mg/100 g), and flavonoids (21.9 6 1.0 mg/100 g). The predominant phytochemicals of carotenoids in AV are xantophylls, specifically lutein and cryptoxanthin contributed 90% of the total carotenoids in Hass AV (Lu et al., 2005). This Algarvian AV fruit has comparable levels of phenolics (Wang et al., 2010) and flavonoids (Rodrı´guez-Carpena et al., 2011a) to the Mexican Hass AV. The phenolic levels of this Algarvian fruit are also being reported to be superior to those of Turkish Hass AV fruit (Golukcu and Ozdemir, 2010). Furthermore, another study by Lu et al. (2009) found that the carotenoids content of Californian Hass AV was superior to that of Algarvian AV. However, Algarvian AV has a greater level of carotenoids than that Hass AV fruit from New Zealand (B5.2 μg/g) (Ashton et al., 2006).

4.4.1.2 Seed A study was conducted by Wang et al. (2010) to determine antioxidant capacity, TPC, and major antioxidant compounds in different AV strains and cultivars. Seven cultivars from ripe Florida AVs, that is, Slimcado, Booth 7, Booth 8, Choquette, Loretta, Simmonds, and Tonnage of West Indian or Guatemalan strains were used, while Hass AV of Mexican strain was used for comparison. The AV seed extracts were prepared using a mixture of acetone/water/acetic acid (70:29.7:0.3, v/v/v). Results showed that high TPC and antioxidant capacity were present in AV seed for all cultivars. Overall the seed contained 64% of TPC and contributed 57% antioxidant activity of a whole fruit. Among the cultivars studied the seed of Simmonds showed the highest TPC and antioxidant capacities. Additionally, the TPC and antioxidant activity of AV seed were found to be severalfold higher than raw blueberry. It has been suggested that procyanidins are the major polyphenols found in AV that contributed to the high antioxidant capacities. HPLC-MS data also showed that a small percentage of procyanidins was detected in AV seeds and these had A-type linkage. A-type procyanidins are found to bring additional health-beneficial effects to humans, such as the prevention of urinary tract infections (Howell et al., 2005). In addition, Soong and Barlow (2004) studied the total antioxidant capacity and phenolic content of the edible portion and seed of AV, jackfruit, longan, mango, and tamarind. The authors reported that AV seed and other fruit seeds showed higher phenolic contents and antioxidant activities compared to their edible portions. Ninety-five percent total antioxidant activity and TPC were contributed by the seeds from most of the fruits. The major identified bioactive compounds from AV seed were catechin and epicatechin (Ding et al., 2007). A similar observation was also reported by Matsusaka et al. (2003) where (1)-catechin and (2)-epicatechin isolated from methanol extract of AV seed were found to inhibit lipid peroxidation in 2,20 -azobis (2,4-dimethylvaleronitrile) (AMVN)-induced methyl linoleate peroxidation assay at concentration of 0.1 mM. Moreover, Rodrı´guez-Carpena et al. (2011a) investigated the phenolic composition and antioxidant activity of different solvent extracts of AV seeds from two AV varieties, namely Hass and Fuerte. Different solvents, such as ethyl acetate, 70% acetone, and 70% methanol, were used for the extraction of AV seed. The TPC of Hass seed was significantly (P , .05) higher compared to that of Fuerte. This was due to the high amounts of catechins, procyanidins, and hydrocinnamic acids that were present in Hass seed. However, Fuerte seed extracts showed higher antioxidant activities compared to Hass seed extracts, regardless of the types of solvent used. Among the solvents studied for Fuerte seed, acetone seed extract exhibited the highest antioxidant activity by using CUPRAC, ABTS, and DPPH assays.

4.4.1.3 Peel Avocado was reported to a natural source of antioxidant with the peel presenting with more intense in vitro antioxidant potential than the pulp (Antasionasti et al., 2017; Rodrı´guez-Carpena et al., 2011). Based on the in vitro antioxidant

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Valorization of Fruit Processing By-products

assays using CUPRAC, ABTS, and DPPH assays, peels showed the greatest peroxyl radical scavenging ability when compared to the seeds and pulp, contributed by the presence of the highest TPC and more bioactive compounds (Rodrı´guez-Carpena et al., 2011a,b; Kosi´nska et al., 2012). In a comparison study, Wang et al. (2010) reported that the peel of Hass AV contained the highest TPC and antioxidant activities as shown in ORAC (631.4 6 4.2 μmol TE/g) and DPPH (189.8 6 10.8 μmol TE/g) assays when compared to other AV varieties (Slimcado, Simmons, Loretta, Choquette, Booth 7, Booth 8, and Tonnage). On the other hand, Rodrı´guez-Carpena et al. (2011) reported that the peel of Fuerte contained the highest TPC, followed by Hass, and Shepard. Moreover, Rotta et al. (2016) formulated tea made from AV peel. The total phenolics and flavonoids content, antioxidant activities, chemical and mineral compositions were investigated in dehydrated AV peel and compared with other marketed teas. Avocado peel tea contained 10,848.27 mg GAE/kg phenolic compounds and 1360.34 mg EQ/kg flavonoids, and DPPH antioxidant activity which was the highest (1954.24
2518.27 mg TE/L), followed by apple tea. In 2015, a team of researchers led by Sihombing from Sumatera, Indonesia, conducted phytochemical and antioxidant activity screening of 31 fruit peel extracts. This screening was intended to determine the pharmacological bioactive compounds including saponins, alkaloids, steroids, flavonoids, triterpenoids, and phenolics. This experiment revealed that the fruit peel extracts of AV and mangosteen contained the highest antioxidant activity with the presence of alkaloid, saponins, steroids, flavonoids, triterpenoids, and phenolics. Caffeic acid was found to be present in AV peel by Wong et al. (2016), while p-coumaric acid was detected in AV peel by Saavedra et al. (2017). Several researchers also detected flavanols, namely catechin and epicatechin in AV peel (Fidelis et al., 2015; Morais et al., 2015). In addition to the AV varieties, the extracting solvents also strongly influence the antioxidant activities. Acetone extracts of AV peels (Hass: 8997 mg GAE/100 g; Fuerte: 17,218 mg GAE/100 g) were found to contain the highest TPC, followed by methanolic extracts (Hass: 7841 mg GAE/100 g; Fuerte: 13,770 mg GAE/100 g), and ethyl acetate extracts (Hass: 3293 mg GAE/100 g; Fuerte: 4054 mg GAE/100 g) (Rodrı´guez-Carpena et al., 2011). This was found to be in agreement with Antasionasti et al. (2017) who demonstrated the highest antioxidant activities from methanol-extracted AV peel through DPPH with an IC 50 of 9.467 μg/mL and ABTS of 1.122 μg/mL together with FRAP of 742.863 mg/g sample, when compared to the ethyl acetate and petroleum ether extracts. They also reported that the high antioxidant activity in the methanol extract was strictly contributed by the presence of high levels of phytochemicals, such as phenolics, flavonoids, and vitamin C with reducing properties. To summarize these studies, the seed of AV was found to contain the highest TPC, TFC, and carotenoid, followed by its peel and pulp (Vinha et al., 2013; Wang et al., 2010). However, the peel of AV was reported to be rich in catechins, procyanidins, and hydroxycinnamic acids compared to the seed and pulp (Rodrı´guez-Carpena et al., 2011a, b). Additionally, different active compounds were identified for different varieties of AV. The peel of Shepard variety was found to be devoid of catechins and procyanidins, while peels of Hass and Shepard contained 5-O-caffeoylquinic acid and quercetin derivatives (Kosi´nska et al., 2012). In addition, flavonols were only detected in the peel and seed of AV (Rodrı´guez-Carpena et al., 2011a,b).

4.4.2

Anticancer

Extensive research on chemoprevention has been spurred on by to its high incidence and mortality. Many side effects and expensive costs are faced by the patients when receiving therapy. Therefore it is necessary to explore natural resources as an alternative way to fight cancer (Kristanty et al., 2014). It has been suggested that the risk of human cancers might be reduced by consuming fruits and vegetables. This was due to the presence of phytochemicals which play important roles in cancer prevention (Ding et al., 2007). Avocado is a potential source of anticancer agents due to its secondary metabolites, such as alkaloids, triterpenoids, tannins, flavonoids, saponins, and polyphenols (Abubakar et al., 2017). Phytochemicals extracted from AV fruit were shown to selectively induce cell cycle arrest, inhibit growth, and induce apoptosis in precancerous and cancer cell lines. Glycosylated quercetin and its analogs, luteolin and apigenin, were widely found in AV and quercetin was found to induce G2/M in U937, lung cancer, prostatic carcinoma cells (PC-3) cell lines, and normal tumor fibroblast cells (Ding et al., 2007). Moreover, 1,2,4-trihydroxyheptadec-16-ene, 1,2,4-trihydroxyheptadec-16-yne, and 1,2,4-trihydroxynonadecane were also isolated previously from the unripe fruits of AV (Oberlies et al., 1998). These compounds were shown to be moderately cytotoxic against a small panel of cancer cell lines (Table 4.4).

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TABLE 4.4 Anticancer compounds of avocado. Extract

Bioactive compound

References

Pulp

Ding et al. (2007)

OH OH HO

O

OH OH

O

Quercetin Pulp

D’Ambrosio et al. (2011)

O CH2

O

H3C

OH

OH

(2S,4S)-2,4-dihydroxyheptadec-16-enyl acetate O H3C

CH

O OH

OH

(2S,4S)-2,4-dihydroxyheptadec-16-ynyl acetate

4.4.2.1 Pulp In the study of D’Ambrosio et al. (2011), the authors reported that the chloroform-soluble extract (D003) of AV fruit exhibited a high growth inhibitory effect toward premalignant and malignant human oral cancer cell lines. Two aliphatic acetogenins, namely (2S,4S)-2,4-dihydroxyheptadec-16-enyl acetate and (2S,4S)-2,4-dihydroxyheptadec-16-ynyl acetate, were isolated from the chloroform extract of AV fruit. A synergistic effect of both compounds was observed through the inhibition of c-RAF (Ser338) and ERK1/2 (Thr202/Tyr204) phosphorylation and human cancer cell proliferation. Therefore these aliphatic acetogenins were suggested as the two key components of the EGFR/RAS/RAF/ MEK/ERK1/2 cancer pathway. Moreover, Lu et al. (2005) investigated the effects of the acetone extract of AV on the proliferation of androgen-dependent and androgen-independent prostate cancer cell lines. The authors found that a higher inhibition of the proliferation of prostate cancer cell cells was observed for AV extract compared to that of pure lutein. This also suggests that other constituents such as carotenoids, vitamins, and other components might have contributed to the growth inhibition of prostate cancer cells (Venkateswaran et al., 2002; Williams et al., 2000). In another study, Larijani et al. (2013) evaluated the effect of ethanol, chloroform, ethyl acetate, and petroleum extracts of AV fruit on esophageal squamous carcinoma and colon adenocarcinoma cell lines. Results showed that all extracts inhibited cancer cell growth effectively compared to the normal cells (P , .05). A higher anticancer effect was observed for esophageal squamous cell carcinoma compared to that of colon adenocarcinoma cells. Among the extracts studied, ethanol extract showed the lowest fatal activity. On the other hand, Paul et al. (2011) showed that the extract of AV fruit with 50% methanol (200 mg/kg body weight) showed the proliferation of human lymphocyte cells and decreased chromosomal aberrations induced by cyclophosphamide.

4.4.2.2 Seed Kristanty et al. (2014) studied the cytotoxic effects of AV seed extracts on breast cancer cells T47D using 3-(4,5dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide assay. Aqueous extract, ethanol extract of AV seeds, and a positive control (doxorubicin hydrochloride) were used in this study. The IC50 value obtained for aqueous extract, ethanol extract, and doxorubicin hydrochloride were 560.2, 107.15, and 0.26 μg/mL, respectively. Based on the results obtained, the ethanol extract of AV seeds showed a higher inhibition on the growth of T47D compared to that of the aqueous extract. This was due to the presence of polar groups of active compounds such as phenols, glycosides, saponins, and alkaloids.

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In another study, Abubakar et al. (2017) isolated a triterpenoid compound with molecular mass 505 g/mol from the ethanol extract of AV seed. The isolated triterpenoid showed an inhibition of cell proliferation toward MCF7 and Hep G2 cell lines with an IC50 value of 62 and 12 μg/mL, respectively. According to the American National Cancer Institute (NCI), the recommended IC50 value of bioactive compounds to have in vitro anticancer effect is below 30 μg/mL (Graidist et al., 2015). Additionally, the safe concentration limit on normal cells for the toxicity test of the ethanol extract was 100 μg/mL. Thus this isolated triterpenoid showed a potential effect in inhibiting liver cancer. Lee et al. (2008) also reported that a methanol extract of AV seed at 100 μg/mL was found to be effective in treating malondialdehyde (MDA)-MB-231 human breast cancer cells via apoptosis. This effect was associated with the increased cleavage of caspase-3, caspase-7, and poly (adenosine diphosphate (ADP) ribose) polymerase.

4.4.3

Antidiabetic

In an earlier finding, P. americana was demonstrated as a potent inhibitor for glucose movement in vitro by retarding the diffusion of glucose in the intestinal tract (Gallagher et al., 2003). Diabetic patients are found to be affected by the rise of blood glucose level in a state known as hyperglycemia, caused by the elevation of starch hydrolysis and uptake of glucose through pancreatic α-amylase and intestinal α-glucosidase. The inhibition of hydrolyzing enzymes, α-amylase and α-glucosidase, will delay the absorption of glucose and improve the hyperglycemic condition (Fig. 4.6) (Isaac et al., 2014; Oboh et al., 2014).

4.4.3.1 Pulp For overweight and moderately obese individuals, the addition of 70 g AV to lunch was reported to increase the satiety over a period of 3
5 subsequent hours, and a reduction of insulin secretion in a 3-h postprandial period (Wien et al., 2013). Lerman-Garber et al. (1994) studied the effect of a high-monounsaturated fat diet enriched with AV in 12 noninsulin-dependent diabetes mellitus (NIDDM) women patients. A partial replacement of complex digestible carbohydrates with monounsaturated fatty acids of AV fruit in the diet of NIDDM patients improved the lipid profile with adequate glycemic control. It has been reported that fat, protein, minerals, vitamin E, vitamin C, β-carotene, thiamine, FIGURE 4.6 Mechanism of action of antihyperglycemic effect of avocado.

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riboflavin, nicotinic acid, and foliate from AV exert antidiabetes potential and are beneficial for the treatment of type 2 diabetes (Sharma and Vikrant, 2011). Rao and Adinew (2011) also investigated the insulin-stimulative effect of AV fruit extract in 24 streptozotocin (STZ)-induced diabetic rats over 30 days. The rats were divided into four groups: control normal rats, STZ-induced diabetic rats, STZ-induced diabetic rats treated with aqueous AV fruit extract (300 mg/kg body weight), and STZ-induced diabetic rats treated with gliclazide as positive controls (5 mg/kg body weight). Diabetic rats fed with AV fruit extract and gliclazide showed a decreased in blood glucose level while the insulin level was increased in STZ-induced diabetic rats. In addition, the glycosylated hemoglobin level was also decreased and proteolysis caused by insulin deficiency was inhibited in diabetic rats upon administration of AV fruit extract and gliclazide. This hypoglycemic effect of AV was mainly due to an increased secretion of insulin via stimulation of the remaining pancreatic β cells in animal models. The TPC of AV may also prevent the progressive impairment of pancreatic β cells function caused by oxidative stress and thereby reduce the occurrence of type 2 diabetes (Song et al., 2005). Additionally, Oboh et al. (2014) studied the effect of methanol extracts (phenolic extracts) of AV fruit on some key enzymes that are linked to type 2 diabetes, such as α-amylase and α-glucosidase, and sodium nitroprusside (SNP)induced lipid peroxidation in rats pancrease. The AV fruit extract showed inhibitory effects on both α-amylase and α-glucosidase activities. MDA content in the tissue was also decreased after the introduction of phenolic extracts. Therefore an inhibition of the enzymes linked to type 2 diabetes and prevention of oxidative stress in the pancreas could be the possible mechanisms for the antidiabetes properties of AV fruit.

4.4.3.2 Seed Avocado seed extracts were shown to possess the ability to reduce blood glucose and ameliorate diabetes. The ethanol seed extract (450 or 900 mg/kg body weight) was used to treat 30 alloxan-induced diabetic rats for 14 days. Results showed that the blood glucose levels were reduced by 46.60%
55.14% upon consumption of ethanol seed extract (Edem, 2009). The ethanol seed extract also showed a protective effect on pancreatic islet cells from the histological examination of the pancreases of the treated rats. Edem et al. (2009) also investigated the effects of aqueous extract of AV seed on normal and alloxan-induced diabetic rats (five rats per group). The rats were treated with 300 mg and 600 mg/kg body weight of AV seed extracts. Blood glucose levels of alloxan-induced diabetic and normal rats were reduced by 73%
78% and 35%
39%, respectively. This was due to the presence of insulin-mimetic substance in the extract which stimulated production of insulin by β cells and enhanced the utilization of glucose, leading to hypoglycemic effects. On the other hand, Alhassan et al. (2012) evaluated the effect of AV aqueous seed extract on 25 alloxan-induced diabetes rats. The rats were divided into five groups of five rats each: group 1, normal untreated albino rats (NC); group 2, diabetic untreated albino rats (DC); group 3, diabetic treated albino rats (DGI), 400 mg/kg dose; group 4, diabetic treated albino rats (DGII), 800 mg/kg; and group 5, diabetic treated albino rats (DGIII), 1200 mg/kg dose. The blood sugar of the rats was recorded after 2 weeks and 4 weeks, and 1 week after the withdrawal of the extract. A reduction in blood glucose was observed for all groups after 4 weeks except for group 2. However, the blood glucose was increased after 1 week’s withdrawal of the extract. The hypoglycemic effect of the AV aqueous seed extract might be due to insulin stimulatory substances and probable contents of minerals. Minerals have been suggested to play a crucial role in blood glucose homeostasis by regulating the key enzymes of gluconeogenesis in the liver. Moreover, Ezejiofor et al. (2013) studied the hypoglycemic and tissue-protected effects of hot aqueous AV seed extract on 30 alloxan-induced Wistar albino rats. Hot aqueous AV seed extracts at different concentrations (20, 30, and 40 g/L) were used to treat the rats for 21 days and compared with the reference drug, glibenclamide. The extract exhibited significant (P , .05) hypoglycemic effect and reversed the histopathological damage that occurred in alloxaninduced diabetic rats. The effects were achieved by increasing glucose metabolism, and controlling muscle wasting, that is, the reversal of gluconeogenesis. These results also showed that AV seed not only possessed antidiabetes properties but also showed protective effects on pancreas, kidney, and liver tissues of rats. The presence of flavonoids, tannins, and saponins in the extract was believed to contribute to these beneficial effects. A similar observation was reported by Aigbiremolen et al. (2017) where the blood glucose of diabetic treated rats was reduced upon consumption of 500 mg/kg aqueous extract of AV seed for 28 days.

4.4.4

Antiatherogenic

CVD is one of the leading causes of high mortality and morbidity worldwide. It might happen due to the progression of atherosclerosis. The susceptibility of atherosclerosis might also be due to the continuous consumption of a

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TABLE 4.5 Antiatherogenic and antiplatelet compounds of avocado. Extract

Bioactive compound

Seed

CH 3

H 3C

Properties

References

Antiatherogenic effect

Ovesna´ et al. (2004)

Antiplatelet effect

Rodriguez-Sanchez et al. (2014)

CH 3 CH 3

H 3C

HO

β-sitosterol Pulp

CH3 O

CH3

O OH

O

Persenone C

high-cholesterol diet which subsequent leads to hypercholesterolemia or obesity (Grundy, 2004; Malik et al., 2004). In addition, the occurrence of atherosclerosis can also be attributed to atherothrombotic events. Atherothrombosis is the phenomenon where a blood clot forms within an artery. It has been reported that platelets play an important role in human physiological hemostasis to stop bleeding by forming blood clot. Thus it is crucial to identify the agent with antiplatelet actions to protect against arterial thrombosis and reduce the possibility of CVD (Jennings, 2009). Past studies showed that AV might possess antiatherogenic effects and act as an antiplatelet agent (Table 4.5).

4.4.4.1 Pulp According to Gouegni and Abubakar (2013) significant (P , .05) decreases in prothrombin time (PT) and partial thromboplastin time (pTT) were found for rats (n 5 8) fed with AV at a concentration of 10 g/kg body weight for 8 weeks when compared to control rats fed with a powdered diet. The PT and pTT were used to evaluate extrinsic and intrinsic coagulation pathways using thromboplastin-calcium and kaolin reagent, respectively. These results indicate that AV is able to regulate the blood clotting time due to its significant vitamin K content. Vitamin K is essential for the synthesis of prothrombin and some other clotting factors. Furthermore, Rodriguez-Sanchez et al. (2014) reported that AV pulp demonstrated inhibitory effects on platelet aggregation when tested in vitro using ADP, arachidonic acid, or collagenplatelet aggregation assay. The presence of a bioactive compound, persenone C, was identified from the AV pulp as the most potent antiplatelet acetogenin (IC50 5 3.4 mM). This indicates that the consumption of AV pulp might be useful in preventing the thrombus formation that may occur in ischemic disease. On the other hand, Shehata and Soltan (2013) investigated the antihypercholesterolemic effects of AV pulp on 12 hypercholesterolemia rats over 6 weeks. The rats were randomly divided into treatment and control groups. For the treatment group, the rats were fed with a high-cholesterol diet supplemented with 30% AV pulp while control rats were fed with a high-cholesterol diet (1% cholesterol 1 16% fat and 0.2% cholic acid). The authors reported that the triglyceride (TG), total cholesterol, and LDL levels were decreased in the hypercholesterolemia rats by 38.21%, 22.48%, and 29.27%, respectively, upon consumption of AV pulp. Additionally, the supplementation of AV pulp in the diet also increased the HDL levels by 31.33% in the hypercholesterolemic rats compared to control group. This antihypercholesterolemic effect was due to the presence of monounsaturated fatty acid, fiber (12.84%), flavonoids (2.96 mg/ 100 g CE), sterols, and phenolic compounds (259.15 mg/100 g GAE), such as ellagic acid, in AV pulp which improved the lipid profiles of hypercholesterolemia rats. In another study, Elbadrawy and Shelbaya (2013) reported the hypocholesterolemic effects of AV on the lipid profile of five hypercholesterolemia rats. A significant reduction of artherogenic indices (cholesterol/HDL-cholesterol, P..05; LDL/HDL-cholesterol, P..001) was found for hypercholesterolemia rats fed with 130 and 150 mg/kg of hydroalcoholic extract of AV compared to that of the control group. Monika and Geetha (2016) further validated the in vivo hypocholesterolemic effect of AV pulp extract by treating six high-fat diet (HFD)-induced obesity male Sprague
Dawley rats with HFD together with 25, 50, 100, and 200 mg of hydroalcoholic extract of AV per kg of body

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weight. The administration of hydroalcoholic extract of AV was also found to reduce total cholesterol, TG, and LDL levels in a dose-dependent manner. This significant reduction of blood cholesterol was found to be attributed to the inhibition of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase activity and increased lipoprotein lipase activity when coadministrated with AV. Inhibition of HMG-CoA reductase activity helps in inhibiting the conversion of HMG-CoA to mevalonate while lipoprotein lipase allows the catabolism of triacylglycerol and the release of free fatty acids from lipoproteins (Monika and Geetha, 2016). At the gene expression level, Monika and Geetha (2015) reported that the suppression of lipogenesis, fatty acid oxidation-related gene, and fibroblast growth factor-21 gene were found with coadministration of 100 mg/kg body weight of hydroalcoholic extract of AV. This implied that AV was able to modulate the endogenous fat synthesis and adiponectin formation as well as exhibiting good hypocholesterolemic effect. Moreover, Padmanabhan and Arumugam (2014) found that the body mass index, total fat pad mass, and adiposity index were decreased when six obese rats were fed with a HFD and hydroalcoholic fruit extract of AV at the dosage of 100 mg/kg body weight. An increase in the mRNA level of adiponectin expression, an adipose tissue marker with antiatherogenic function, was found in the obese rats. This finding was further supported by Naveh et al. (2002) in which the authors reported that 10 rats fed with dried defatted AV pulp were found to have lower body weight gain. This suggests that AV pulp may interfere with the hepatic fat metabolism by reducing hepatic total fat levels. Additionally, AlDosari (2011) found a significant (P , .01) reduction in a cardiac tissue damage marker, cardiac nonprotein sulfhydryl, for the rats fed with 1% cholesterol together with 1 mL of viscous slurry-like AV pulp for 70 consecutive days without causing toxicity, and it showed a protection effect for liver and heart tissues against oxidative stress. Other than in vivo studies on animal models, a clinical trial has been conducted to evaluate the antihypercholesterolemic effect of AV pulp on 45 healthy, overweight, and obese subjects (Wang et al., 2015). All the study subjects were randomly assigned to a treatment sequence of three diet periods (lower fat (LF), moderate fat (MF), and avocado (AV) diets) with 5 weeks each and 2-week compliance break. The LF diet was given by substituting 6%
7% of the energy from saturated fatty acid (SFA) with carbohydrate; the MF diet was given by substituting 6%
7% of the energy from SFA with monounsaturated fatty acid using high oleic acid oils including sunflower and canola oils, while the AV diet was given by substituting 6%
7% of the energy from SFA with one fresh AV per day (136 g). The menus were developed using Food processor SQL software for seven calorie levels (1800
3600 kcal) in order to meet the participants’ energy requirements. The study was found to have a good compliance rate where the adherence for all participants to consume all three diets was 43 out of 45 recruited study subjects. All the three diets decreased LDL and total cholesterol levels compared to the baseline average American diet (AAD; 34% fat, 51% cholesterol, 16% protein). Among the diets studied, the AV diet was more effective in reducing the LDL and total cholesterol levels of subjects by 10% and 8%, respectively, compared to the LF and MF diets due to the richness of β-sitosterol in AV.

4.4.4.2 Seed Antiatherogenic activity of AV seed was attributed to the presence of β-sitosterol (Giffoni-Leite et al., 2009). Manal and Sahar (2013) studied the effect of kiwi fruit and AV (pulp and seed) on 25 diet-induced hypercholesterolemia rats. The authors found that the atherogenic index (AI) and LDL-cholesterol/HDL-cholesterol ratio were decreased for hypercholesterolemia rats fed with 10%, 20%, and 30% AV seeds in comparison to the hypercholesterolemia control group. Oral consumption of a diet supplemented with 30% AV seed showed 32.2% reduction in total glyceride level in the liver tissue of hypercholesterolemic rats. This was in accordance with Imafidon and Amaechina (2010), where the authors found a reduction of triacylglycerol levels by 36.19% in the liver tissue of hypertensive rats treated with 500 mg/kg body weight of aqueous extract of AV seed. β-Sitosterol and tocopherols were found in the seeds which lowered the cholesterol level. However, there was an increase of 20%
24% in the cholesterol levels of hypertensive rats compared to the hypertensive controls after the administration of 700 mg/kg body weight of aqueous extract of AV seed. The increased cholesterol levels may be due to the undesirable increase in antioxidant levels. Past studies have shown that antioxidants will lose their beneficial effects when present in excess amounts (Murakoshi et al., 1989; Serbinova et al., 1992). In addition, hypothyroidism may be produced by aqueous AV seed extract, which subsequently increases cholesterol level. Imafidon and Amaechina (2010) also suggested that the use of AV seed in the hypertension treatment should be dosedependent as high concentrations of extract may increase the cholesterol levels that lead to atherosclerosis. A higher TPC (285.43 mg/100 g GAE) was also found in AV seed extract compared to the AV fruit and kiwi fruit (Manal and Sahar, 2013). This was in agreement with Wang et al. (2010), where the AV seed contained the highest TPC and antioxidant activity. Besides phenolic compounds, TFC (3.21 mg/100 g CE) and soluble dietary fiber (38%) were also higher in AV seed, followed by AV and kiwi fruits. Dietary fiber, especially soluble fiber, can effectively decrease serum cholesterol and LDL-cholesterol by decreasing the absorption of bile acids.

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4.4.5

Antimicrobial effect

From time to time, the use of AV for its antimicrobial effect has drawn the attention of people worldwide as it leads to fewer side effects plus reduced toxicity when compared to synthetic drugs (Nedd et al., 2015). Other than being used as synthetic drugs to treat microbial infection, there is potential for those bioactive compounds to be used in the food industry to control the growth of microbial pathogens as well as to inhibit microbial spoilage. Avocado could potentially be used as a natural food additive in food preservation to prevent the production of unsafe food caused by bacterial contamination (Conte et al., 2007). Table 4.6 shows the antimicrobial compounds that have been isolated and identified by some researchers. TABLE 4.6 Antimicrobial compounds of avocado. Extract

Bioactive compound

Seed

References Giffoni-Leite et al. (2009)

CH 3

H 3C

CH 3 CH3

H 3C

HO

β-sitosterol

Pulp

OH

OH

OH

OH

Lu et al. (2012)

HO CH2

Avocadenol A

HO

CH OH

OH

Avocadenol B

HO

CH3

(2R,4R)-1,2,4-trihydroxynonadecane OH

OH HO

CH2

(2R,4R)-1,2,4-trihydroxyheptadec-16-ene Seed

OH

Falodun et al. (2014)

OH

HO

CH2

(2S,4S) 1, 2, 4-trihydroxyheptadec-16-ene OH

OH

HO

CH2 OH

1,2,4,15-tetrahydroxyheptadec-6,16-diene OH

OH CH

HO

1,2,4-trihydroxyheptadec-16-yne OH

OH

HO

CH3

1,2,4-trihydroxynonadecane OH

OH

HO

CH

1,2,4-trihydroxyheptadec-6-ene,16-yne

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4.4.5.1 Pulp Lu et al. (2012) reported antimycobacterial activities by the isolated secondary metabolites from dried unripe AV pulp against Mycobacterium tuberculosis using cold methanol extraction at room temperature. Four isolates from the pulp, consisting of avocadenol A (C17H32O3), avocadenol B (C17H30O3), (2R,4R)-1,2,4-trihydroxynonadecane, and (2R,4R)1,2,4-trihydroxyheptadec-16-ene, were found to have minimal inhibitory concentration (MIC) values of 24.0, 33.8, 24.9, and 35.7 μg/mL, respectively, against M. tuberculosis, using ethambutol as positive control (6.25 μg/mL). Avocodenol A and B are two optically active colorless oils found in the pulp with the triol moiety of the compounds exhibiting antimycobacterial activities. Avocadenol A with a terminal methylene showed the strongest MIC against M. tuberculosis compared to the other tested compounds (Lu et al., 2012). Nedd et al. (2015) also reported the aqueous, ethanol, and hexane extracts of pulp (10 g/100 mL) demonstrated antimicrobial effect on Staphylococcus aureus, Escherichia coli and Aspergillus flavus in disc diffusion method. Ethanol extract of AV showed the strongest antibacterial effect with the highest zone of inhibition on S. aureus (14.75 mm) compared to E. coli (8.75 mm) and A. flavus (10.25 mm). This antibacterial effect could be contributed by the phytochemical activity of the AV pulp due to the presence of phytoconstituents of catecholic tannins, reducing sugars, glycosides, and steroids. However, aqueous-extracted AV demonstrated no antibacterial effects due to its low TPC.

4.4.5.2 Seed Giffoni-Leite et al. (2009) investigated the antimicrobial effect of hexane and methanol extracts of AV seeds against Candida spp., Crytococcus neoformans, and Malassezia pachydermatis using the microdilution method. The results showed that hexane and methanol extracts of AV seed were able to inhibit the growth of Candida spp., Cryptococcus neoformans, and M. pachydermatis with minimum inhibition concentrations (MICs) of less than 1.00 mg/mL. It has been suggested that MIC values # 1.00 mg/mL indicated important data for phytotherapy drugs with potential antifungal effects. Egbuonu et al. (2018) also found that the ethanol extract of AV seed showed antifungal activities against Aspergilus niger (18 6 0.31 mm) and Candida albicans (32 6 0.14 mm). Two chemical constituents, that is, 1,2,4-trihydroxy-nonadecane and β-sitosterol, were isolated and identified from hexane extract of AV seed. β-Sitosterol has been reported to possess not only antiinflammatory but also antibacterial and antifungal effects (Ovesna´ et al., 2004). Additionally, Salinas-Salazar et al. (2016) also reported that fatty acid derivatives (acetogenins) extracted from AV seed showed inhibitory activity against Listeria monocytogenes. Moreover, Chia and Dykes (2010) studied the antimicrobial activity of ethanol and water extracts of AV seed from mature AV fruit of three cultivars: Hass, Shepard, and Fuerte. A higher antimicrobial activity was observed for ethanol extracts of AV seed compared to water extracts, regardless of their cultivars. The ethanol seed extracts of different cultivars also showed higher antibacterial activities against Gram-positive bacteria (L. monocytogenes, S. aureus, and Enterococcus faecalis) and Gram-negative bacteria (Salmonella Enteritidis, Citrobacter freundii, Pseudomonas aeruginosa, Salmonella typhimurium, and Enterobacter aerogenes). The MIC values for L. monocytogenes and S. aureus were 125.0 and 208.3 μg/mL, respectively, using ethanol extract of Fuerte seed, whereas an MIC value of 250 μg/mL was observed for E. faecalis using ethanol extract of Shepard seed. For Gram-negative bacteria, the MIC value for Salmonella Enteritidis was 125.0 μg/mL with the use of ethanol extracts of Hass seed; 145.8, 166.7, and 250 μg/mL for C. freundii, P. aeruginosa, and S. Typhimurium, respectively, using ethanol extract of Shepard seed; and 125.0 μg/mL for E. aerogenes using ethanol extracts of Shepard and Hass seed. A similar observation was reported by Egbuonu et al. (2018), where ethanol extracts of AV seed showed inhibition activities against Proteus mirabilis (23 6 0.14 mm), S. aureus (16 6 0.04 mm), and P. aeruginosa (15 6 0.11 mm). In another comparison study, Rodrı´guez-Carpena et al. (2011a) evaluated the antimicrobial activity of acetone extracts of AV seed from Hass and Fuerte cultivars using the disc diffusion method. The authors reported that Hass exhibited a higher inhibition zone compared to that of Fuerte. Additionally, AV seed extracts showed more intense effects against Gram-positive bacteria than Gram-negative trains. This was due to an extra protective outer membrane on Gram-negative bacteria which is more resistant to antibacterial agents. Among the Gram-positive bacteria studied, the acetone extracts of Hass AV seed showed the highest inhibitory effects against Bacillus cereus and L. monocytogenes with inhibition zones of 9.20 6 1.51 and 9.27 6 0.46 mm, respectively. For the Gram-negative bacteria studied, E. coli was the most sensitive bacteria with an inhibition zone of 7.67 6 2.31 mm in the presence of the acetone extract of Fuerte AV seed, whereas no inhibition was observed for the acetone extract of Hass AV seed.

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Furthermore, Falodun et al. (2014) investigated the potential use of aliphatic fatty alcohols extracted from AV seed as antimicrobial agents. Five known aliphatic fatty alcohols were isolated and identified as (2S,4S)-1,2,4-trihydroxyheptadec16-ene (1), 1,2,4,15-tetrahydroxyheptadecane-6,16-diene (2), 1,2,4-trihydroxyheptadec-16-yne (3), 1,2,4-trihydroxyheptadecane (4) and 1,2,4-trihydroxyheptadec-6-ene-16-yne (5). Among the aliphatic fatty alcohols, compounds (1) and (2) showed moderate activity against S. aureus with IC50 . 200 μg/mL. A strong activity against methicillin-resistant S. aureus (MRSA) with IC50 of 13.81 μg/mL was exhibited by compound (1). Compound (5) showed the most promising antifungal activity with IC50 , 8 μg/mL for all the fungi tested (C. albican, Candida glabrata, Candida krusei, C. neoformans, and Aspergillus fumigatus). Considering that C. neoformans is the dominant pathogenic organism in HIV/AIDS patients, therefore AV seed extracts might be effective and useful in managing HIV infection and AIDS treatment. On the other hand, Cardoso et al. (2016) reported that AV seed extracts showed weak inhibitory activities against Streptococcus agalactiae strains from human sources, with an inhibition zone between 7 and 9.5 mm, and showed no inhibition against S. agalactiae isolated from a fish source. These indicate that antibacterial and antifungal effects of AV seed may depend on the source of bacteria being isolated, the solvent used for extraction, and the type of strain. Other than antibacterial and antifungal properties, Jime´nez-Arellanes et al. (2013) studied the antiprotozoal and antimycobacterial activities of AV seed. The chloroform and ethanol extracts of AV seed exhibited activity against Entamoeba histolytica, Giardia lamblia, and Trichomonas vaginalis with IC50 , 0.634 μg/mL. M. tuberculosis H37Rv, M. tuberculosis MDR SIN 4 isolate, three M. tuberculosis H37Rv monoresistant reference strains, and four nontuberculosis mycobacteria (M. fortuitum, M. avium, M. smegmatis, and M. absessus) were inhibited by chloroform extract with an MIC value of ,50 μg/mL. However, the ethanol seed extract only showed inhibition against two monoresistant strains of M. tuberculosis H37Rv and M. smegmatis with an MIC value of ,50 μg/mL. It was speculated that the extract of AV seed possessed antimicrobial activity due to the presence of antinutrients, notably saponins, alkaloids, and flavonoids (Rimando and Perkins-Veazie, 2005; Okwu and Morah, 2007).

4.4.5.3 Peel Many studies have proved that different varieties of AV peel demonstrate antimicrobial effects on either bacteria or fungi. According to Chia and Dykes (2010), the peel of AV from the Hass, Shepard, and Fuerte cultivars demonstrated different levels of antimicrobial effects. Shepard exhibited a broader antibacterial effect on seven bacterial strains with MIC below 500 μg/mL compared to peel extracts of Hass and Fuerte. The MIC for L. monocytogenes, Salmonella Enteritidis, C. freundii, S. aureus, S. Typhimurium, P. aeruginosa, and E. aerogenes were 416.7, 208.3, 166.7, 416.7, 375, 166.7, and 250 μg/mL, respectively. However, the peel extract of Shepard showed a weaker antifungal effect compared to the peel extract of Fuerte. The peel extract of Fuerte demonstrated the strongest antifungal effect on Zygosaccharomyces bailii with the MIC of 166.7 μg/mL. Additionally, Rodrı´guez-Carpena et al. (2011) reported that AV peel extract only exhibited antimicrobial effects on Gram-positive bacteria but not Gram-negative bacteria. The disc diffusion method was used to test five bacterium strains using 20 μL of peel, seed, and pulp acetone/water-extracts (70:30, v/v) from the AV varieties of Hass and Fuerte. Although peel extracts of AV demonstrated antimicrobial activity, the strongest antimicrobial activity was found in pulp extracts followed by seed and peel extracts. The pulp extracts of AV showed higher inhibition zones against B. cereus (Fuerte: 10.07 mm; Hass: 8.33 mm), Staphylococcus aurues (Fuerte: 8.93 mm; Hass: 6.47 mm), L. monocytogenes (Fuerte: 11.00 mm; Hass: 7.00 mm), and Yarrowia lipolytica (Fuerte: 5.53 mm; Hass: 5.33 mm). Chia and Dykes (2010) also reported that the seed extract demonstrated better antibacterial and antifungal effects compared to the peel extract. Overall, the pulp extract of AV showed the strongest antimicrobial activity despite having lower TPC than the peel and seed extracts. This indicates that pulp may contain more active compounds with antimicrobial activity (Rodrı´guez-Carpena et al., 2011; Chia and Dykes, 2010).

4.4.6

Antiinflammatory effect

Phospholipase A (PLA2) is an enzyme that plays an important role in inflammation. This enzyme releases arachidonic acid from membrane phospholipids at the sn-2 position. Arachidonic acid is the precursor of several eicosanoids such as cyclooxygenase-derived prostaglandins and lipoxygenase-derived leukorienes. These eicosanoids act as lipid mediators of inflammation (Sudhir, 2005). In the earlier study, Kim et al. (2000b) reported that the active compound isolated from AV fruit, persenone A, was able to exhibit antiinflammation effects by acting on lipopolysaccharide and interferon-γ-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in mouse macrophage. Table 4.7 shows antiinflammatory compounds isolated from AV.

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TABLE 4.7 Antiinflammatory compounds of avocado. Extract

Bioactive compound

Seed

References Etozioni (2003)

CH3 CH2

O

O

OH

OH

1-acetoxy-2,4-dihydroxy-n-heptadec-16-ene (olefin A) CH3 O

CH

O OH

OH

1-acetoxy-2,4-dihydroxy-n-heptadec-16-yne (acetylene A) OH

OH

HO

CH2

1,2,4-trihydroxy-n-heptadec-16-ene (olefin B) OH

OH CH

HO

1,2,4-trihydroxy-n-heptadec-16-yne (acetylene B) Whole fruit

Kim et al. (2000a)

CH3 O

CH3

O OH

O Persenone A

4.4.6.1 Pulp A food nutrition human trial study was done by Li et al. (2013) to examine the antiinflammatory effects of AV pulp on 11 healthy male volunteers. The authors reported that consumption of a 250 g hamburger (high-fat meal) with AV pulp was able to attenuate the postprandial vasoconstriction after ingestion of hamburger for 2 h when tested using peripheral arterial tonometry. In addition, there is a significant preservation of IKappa-B-alpha (Iκβ-α) protein concentration, an inverse marker of the stimulation of NF-kB in which NF-kB is one of the transcription factors in the inflammation pathway with no changes on interleukin-6 (IL-6, a plasma inflammatory biomarker). All these suggested that AV pulp is able to inhibit the peripheral inflammation, especially inflammation via the NF-kB pathway (Li et al., 2013).

4.4.6.2 Seed In the study of Etozioni (2003), the author successfully isolated several lipidic polyols from AV seeds and these lipidic polyols were found to inhibit the secretion of PLA2. These lipidic polyols were then identified as 1-acetoxy-2,4dihydroxy-n-heptadec-16-ene (olefin A), 1-acetoxy-2,4-dihydroxy-n-heptadec-16-yne (acetylene A), 1,2,4-trihydroxyn-heptadec-16-ene (olefin B), and 1,2,4-trihydroxy-n-heptadec-16-yne (acetylene B). The concentrations of olefin A, acetylene A, olefin B, and acetylene B for complete inhibition were observed to be 12.2, 7.5, 0.17, and 0.08 mM, respectively. In another study, Rosenblat et al. (2010) investigated the effects of polyhydroxylated fatty alcohols (PFAs) extracted from AV seeds on ultraviolet B (UVB)-induced damage and inflammation in skin cells. The authors found that treatment of keratinocytes with PFA at 1 μg/mL for 60 min prior to exposure to UVB reduced cellular damage and the generation of proinflammatory mediators such as IL-6 and prostaglandin E2 (PGE2) The major antiinflammatory constituents in PFA derived from AV seeds were identified as olefin A and acetylene B. Moreover, Kristanti et al. (2017) used a trial involving 45 male mice to evaluate the antiinflammatory effects of AV seed. All mice were induced paw edema using 1% carrageenan and randomly divided into nine groups. The negative control groups I and II were fed with distilled water and carboxymethyl cellulose sodium, respectively; a positive

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control group III was fed with Cataflam Fast 4.48 mg/kg of body weight, while experiment groups IV
VI were fed with 0.67, 1.33, and 2.67 g/kg of body weight of AV seed infusions, respectively; and experimental groups VII and IX were fed with 0.83, 1.67, and 3.33 g/kg of body weight of AV seed methanolic extract. The feeding was done once after 15 min of carrageenan injection to subplantar and antiinflammatory analysis was carried out over 6 h. The authors reported that all doses of AV seed infusions and methanolic extracts showed antiinflammatory activities in mice. Among the doses studied, AV seed infusion (0.67 g/kg of body weight) and methanolic extract (3.33 g/kg of body weight) showed antiinflammatory activities that were comparable to the positive control. This effect was due to the presence of flavonoids in AV seeds. Flavonoids have been reported to exhibit antioxidant activity by scavenging free radicals produced from inflammation (Arukwe et al., 2012; Gomez et al., 2014; Prochazkova et al., 2011). These findings also suggest that bioactive compounds found in AV seeds may be effective in treating inflammation.

4.5

Industrial applications

This climatic fruit does not ripen on the tree. It is either consumed raw or cooked. It can be served as a culinary herb, salad fruit, or vegetable salad. Additionally, AV is processed into guacamole at 22 C for sandwich spread in Brazil (Duarte et al., 2016). Other than being processed into guacamole, AV is incorporated into sorbets and ice-cream in Brazil and Mexico, squeezed with cheese in Nicaragua, and rolled with sushi in Japan. Avocado pulp is also blended with olive oil, green olive, lemon juice, and capers to steam fish in Cuba. Furthermore, the AV extract is coalesced with rum, coffee, and milk, and served as a refreshing drink. It is also blended with garlic, salt, and coconut to consume as an entre´e in the Caribbean. Moreover, AV pure´e is amalgamated with milk and sugar, and consumed as a sweetened dessert in Taiwan and the Philippines (Food and Agriculture Organization of the United Nations FAO, 1999). Avocado seed was also fully utilized and processed into flour and candy. Various compositions of AV seed flour were blended well with proportionate percentages of ginger to prepare AV seed candies. Physical qualities such as moisture content and total sugar of candy were quantified. The sensorial quality of AV candy was also tested and the scores collected showed above average in terms of texture, taste, and flavor (Ifesan et al., 2015). Apart from being used as the raw material in the food industry, it is also widely used in the production of soap, skin care, shampoo, and oil products. With its supreme mesocarp color and its availability throughout the year, Hass ecotype is the predominant choice for the AV oil industry. Several extraction methods such as pressing (Qin and Zhong, 2016), heating (Berasategi et al., 2012), organic solvents with the use of hexane:acetone and ethanol:carbon dioxide mixtures (Moreno et al., 2003; Corzzini et al., 2017), ultrasound treatment (Martı´nez-Padilla et al., 2018), combination of pressing and organic solvent followed by freeze-drying (Qin and Zhong, 2016), convective drying process (Saavedra et al., 2017), and enzyme-assisted aqueous extraction (Qin and Zhong, 2016) have been used to process AV oil. Even though hexane extraction may yield up to 59% AV oil, there may be a minute amount of hexane residue in the extracted oil and cake still (Qin and Zhong, 2016). Despite drying kinetic analysis of the convective drying process, the data showed a higher water diffusivity among seeds than that of peels, but seeds retained relatively lower amounts of total phenolic compounds than the peel (54.8% vs 62.8%). The convective drying process is less widely used in the AV industries because the valuable nutritional contents of AV such as total phenolic compounds is removed along with its moisture (Saavedra et al., 2017). Therefore cold-pressed technology is always preferred for AV oil extraction. The quality of AV oil that is widely extracted using this technology often outperformed olive oil because of the high amount of monounsaturated fatty acids, coupled with quantifiable amounts of riboflavin, vitamin A, thiamine, niacin, calcium, tocopherols, copper, phosphorus, potassium, iron, and proteins (Costagli and Betti, 2015). Hence AV oil is used in the food industries to prepare sauces, salads, and marinades; and in skin care products as cleansing creams and sunscreen lotions as well as hair conditioners. For example, AV oil is amalgamated with milk for the production of body lotion and facial cream in Korea (Food and Agriculture Organization of the United Nations FAO, 1999). It has also been reported that surfeit AV fruit serves as a pertinent food source for livestock such as swine (Food and Agriculture Organization of the United Nations FAO, 1999). Nonetheless, pulp residues generated from the lipid extraction method are used in the preparation of flour for bakeries (Duarte et al., 2016). Recently, AV seed husks have been suggested to possess potential uses in both plastic and medical industries (Bandyopadhyay, 2017). Benzyl butyl phthalate, identified from the wax of AV seed husks, is a plasticizer for cosmetics production. Likewise, ingredients identified from the AV seed husks oil, such as behenyl alcohol, may serve as antiviral medications, heptacosane can suppress tumor cells growth, and dodecanoic acid is able to promote HDL levels (Bandyopadhyay et al., 2017).

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4.6

89

Conclusion

Avocado is commonly cultivated for human consumption. It has different names in different countries. Its high nutritional value has made it become one of the healthy fruits that is consumed widely. However, the quality of AV may be affected upon exposure to abiotic and biotic stresses. Thus biotechnology has been used to boost the quality and production of AV by increasing its shelf life and controlling fruit ripening. Last but not least, different parts of AV, such as seed, pulp, and peel, have also been evaluated for health-beneficial effects that can be valuable for mankind and industrial applications.

References Abubakar, A.N.F., Achmadi, S.S., Suparto, I.H., 2017. Triterpenoid of avocado (Persea americana) seed and its cytotoxic activity toward breast MCF-7 and liver HepG2 cancer cells. Asian Pac. J. Trop. Biomed. 7 (5), 397
400. Ahmed, M.F., Kantharajah, A.S., Holford, P., 1998. In vitro regeneration of avocado (Persea americana Mill) and transient gene expression. Acta Hort. 461, 339
348. Aigbiremolen, A.A., Ativie, R.N., Aisuodionoe, M.E., Odigie, O.M., Igweh, J.C., Egwaoje, M., 2017. Effect of aqueous extract of Persea americana seed on blood glucose in alloxan-induced diabetic wistar rats.. Asian J. Med. Health 9, 1
10. Ajani, A., Olanrewaju, B.O., 2014. Avocado pear fruits and leaves aqueous extracts inhibit α-amylase, α-glucosidase and snp induced lipid peroxidation
an insight into mechanisms involve in management of type 2 diabetes. Int. J. Appl. Nat. Sci. 3, 21
34. Al-Dosari, M.S., 2011. Hypolipidemic and antioxidant activities of avocado fruit pulp on high cholesterol fed diet in rats. Afr. J. Pharm. Pharmacol. 5, 1475
1483. Alfaro, F.P., Litz, R.E., 2007. Biotechnology and avocado improvement, CAS Yearbooks, 90. pp. 149
167. Alhassan, A.J., Sule, M.S., Atiku, M.K., Wudil, A.M., Abubakar, H., Mohammed, S.A., 2012. Effects of aqueous avocado pear (Persea americana) seed extract on alloxan induced diabetes rats.. Greener J. Med. Sci. 2, 5
11. Antasionasti, I., Riyanto, S., Rohman, A., 2017. Antioxidant activities and phenolics contents of avocado (Persea americana Mill.) peel in vitro. Res. J. Med. Plants 11, 56
61. Arukwe, U., Amadi, B., Duru, M., Agomuo, E., Adindu, E., Odika, P., et al., 2012. Chemical composition of Persea americana leaf, fruit and seed. IJRRAS 11, 346
349. Ashton, O.B., Wong, M., McGhie, T.K., Vather, R., Wang, Y., Requejo-Jackman, C., et al., 2006. Pigments in avocado tissue and oil. J. Agric. Food Chem. 54, 10151
10158. Au, A., Griffiths, L.R., Cheng, K.K., Kooi, C.W., Irene, L., Wei, L.K., 2015. The influence of OLR1 and PCSK9 gene polymorphisms on ischemic stroke: evidence from a meta-analysis. Sci. Rep. 5, 18224
18235. Bandyopadhyay, D., 2017. Avocado seed husks could be a gold mine of medicinal and industrial compounds. Available from: ,https://www.acs.org/ content/acs/en/pressroom/newsreleases/2017/august/avocado-seed-husks-could-be-a-gold-mine-of-medicinal-and-industrial-compounds.html.. Berasategi, I., Barriuso, B., Ansorena, D., Astiasara´n, I., 2012. Stability of avocado oil during heating: comparative study to olive oil. Food Chem. 132, 439
446. Bizimana, V., Breene, W.M., Csallany, A.S., 1993. Avocado oil extraction with appropriate technology for developing countries. J. Am. Oil Chem. Soc. 70, 821
822. Buenrostro, M., Lo´pez-Munguia, A.C., 1986. Enzymatic extraction of avocado oil. Biotechnol. Lett. 8, 505
506. Cardoso, P.F., Scarpassa, J.A., Pretto-Giordano, L.G., Otaguiri, E.S., Yamada-Ogatta, S.F., Nakazato, G., et al., 2016. Antibacterial activity of avocado extracts (Persea americana Mill.) against Streptococcus agalactiae. Int. J. Exp. Bot. 85, 218
224. Carvalho, C.P., Bernal, E., Vela´squez, M.A., Cartagena, V., Re´gulo, J., 2015. Fatty acid content of avocados (Persea americana Mill. cv. Hass) in relation to orchard altitude and fruit maturity stage. Agron. Colomb. 33, 220
227. Centre for Agriculture and Biosciences International, 2018. Persea americana (avocado). Invasive Species Compendium. Available from: ,https:// www.cabi.org/isc/datasheet/39380.. Chia, R.T.W., Dykes, G.A., 2010. Antimicrobial activity of crude epicarp and seed extracts from mature avocado fruit (Persea americana) of three cultivars. Pharm. Biol. 48, 753
756. Conte, A., Speranza, B., Sinigaglia, M., Del Nobile, M.A., 2007. Effect of lemon extract on foodborne microorganisms. J. Food Protect. 70, 1896
1900. Corzzini, S.C., Barros, H.D., Grimaldi, R., Cabral, F.A., 2017. Extraction of edible avocado oil using supercritical CO2 and a CO2/ethanol mixture as solvents. J. Food Eng. 194, 40
45. Costagli, G., Betti, M., 2015. Avocado oil extraction processes: method for cold-pressed high-quality edible oil production versus traditional production. J. Agri. Eng. 46, 115
122. Cruz-Herna´ndez, A., Witjaksono Litz, R.E., Go´mez Lim, M.G., 1998. Agrobacterium tumefaciens
mediated transformation of embryogenic avocado cultures and regeneration of somatic embryos. Plant Cell Rep. 17, 497
503. D’Ambrosio, S.M., Han, C., Pan, L., Kinghorn, A.D., Ding, H., 2011. Aliphatic acetogenin constituents of avocado fruits inhibit human oral cancer cell proliferation by targeting the EGFR/RAS/RAF/MEK/ERK1/2 pathway. Biochem. Biophys. Res. Commun. 409, 465
469. Ding, H., Chin, Y.W., Kinghorn, A.D., D’ Ambrosio, S.M., 2007. Chemopreventive characteristics of avocado fruit. Sem. Cancer Biol. 17, 386
394.

90

Valorization of Fruit Processing By-products

Dorantes, L., Parada, L., Ortiz, A., 2004. Avocado: post-harvest operation. INPho- Post-harvest Compendium. 1
67. Available from: ,http://www. fao.org/fileadmin/user_upload/inpho/docs/Post_Harvest_Compendium_-_Avocado.pdf.. Dreher, M.L., Davenport, A.J., 2013. Hass avocado composition and potential health effects. Crit. Rev. Food Sci. Nutr. 53, 738
750. Duarte, P.F., Chaves, M.A., Borges, C.D., Mendonc¸a, C.R.B., 2016. Avocado: characteristics, health benefits and uses. Cieˆnc. Rural 46, 747
754. Edem, D., Ekanem, I., Ebong, P., 2009. Effect of aqueous extracts of alligator pear seed (Persea americana mill) on blood glucose and histopathology of pancreas in alloxan-induced diabetic rats. Pakistan J. Pharm. Sci. 22, 272
276. Edem, D.O., 2009. Hypoglycemic effects of ethanolic extracts of alligator pear seed (Persea americana mill) in rats. Eur. J. Sci. Res. 33, 669
678. Egbuonu, A.C., Opara, I.C., Onyeabo, C., Uchenna, N.O., 2018. Proximate, functional, antinutrient and antimicrobial properties of avocado pear (Persea americanna) seeds. J. Nutr. Health Food Eng. 8, 1
5. Elbadrawy, E., Shelbaya, L., 2013. Hypolipidemic activities of hydroalcoholic extract of avocado fruit on high cholesterol fed diet in rats and its antioxidant effect in vitro. J. Am. Sci. 9, 337
343. Etozioni, S., 2003. Lipidic polyols from plants as a natural source for phospholipase A2 inhibitors. Biotechnology. Technion Israel Institute of Technology, Haifa. Ezejiofor, A.N., Okorie, A., Orisakwe, O.E., 2013. Hypoglycaemic and tissue-protective effects of the aqueous extract of Persea americana seeds on alloxan-induced albino rats. Malays. J. Med. Sci. 20, 31
39. FAOSTAT, 2018. www.fao.org/faostat/en/. Falodun, A., Erharuyi, O., Imieje, V., Ahomafor, J., Akunyuli, C., Jacobs, M., et al., 2014. In vitro evaluation of aliphatic fatty alcohol metabolites of Persea americana seed as potential antimalarial and antimicrobial agents.. Niger. J. Biotechnol. 27, 1
7. Fidelis, J.C.F., Monteiro, A.R.G., Scapim, M.R.S., Monteiro, C.C.F., Morais, D.R., Claus, T., et al., 2015. Development of an active biodegradable film containing tocopherol and avocado peel extract. Italian Journal of Food Sci. 27 (4), pp. 468
475. Food and Agriculture Organization of the United Nations (FAO), 1999. Report of the expert consultation on avocado production development in Asia and the Pacific. Available from: ,http://www.fao.org/3/a-ab983e.pdf.. Fulgoni, V.L., Dreher, M., Davenport, A.J., 2013. Avocado consumption is associated with better diet quality and nutrient intake, and lower metabolic syndrome risk in US adults: results from the National Health and Nutrition Examination Survey (NHANES) 2001
2008. Nutr. J. 12, 1
27. Gallagher, A.M., Flatt, P.R., Duffy, G., Abdel-Wahab, Y.H.A., 2003. The effects of traditional antidiabetic plants on in vitro glucose diffusion. Nutr. Res. 23, 413
424. Giffoni-Leite, J.J., Salles-Brito, E.H., Cordeiro, R.A., Nogueira-Brilhante, R.S., Costa-Sidrim, J.J., Medeiros-Bertini, L., et al., 2009. Chemical composition, toxicity and larvicidal and antifungal activities of Persea americana (avocado) seed extracts. Med. Trop. 42, 110
113. Golukcu, M., Ozdemir, F., 2010. Changes in phenolic composition of avocado cultivars during harvesting time. Chem. Nat. Compd. 46 (1), 112
115. Gomez, F.S., Sanchez, S.P., Iradi, M.G.G., Azman, N.A.M., Almajano, M.P., 2014. Avocado seeds: extraction optimization and possible use as antioxidant in food. Antioxidants 3, 439
454. Gouegni, E.F., Abubakar, H., 2013. Phytochemical, toxicological, biochemical and haematological studies on avocado (Persea americana) in experimental animals. Niger. Food J. 31, 64
69. Graidist, P., Martla, M., Sukpondma, Y., 2015. Cytotoxic activity of Piper cubeba extract in breast cancer cell lines. Nutrients 7, 2707
2718. Grundy, S.M., 2004. Obesity, metabolic syndrome, and cardiovascular disease. J. Clin. Endocrinol. Metab. 89, 2595
2600. Hamzah, B., 2013. The effect of homogenization pressures on extraction of avocado oil by wet method. Adv. J. Food Sci. Technol. 5, 1666
1667. Hioki, H., Miura, T., Miyashita, Y., Ebisawa, S., Motoki, H., Izawa, A., et al., 2016. Circulating eicosapentaenoic acid to oleic acid ratio and risk for cardiovascular events in patients with coronary artery disease: a sub-analysis of the SHINANO registry. IJC Metabol. Endocr. 10, 1
6. Howell, A.B., Reed, J.D., Krueger, C.G., 2005. A-type cranberry proanthocyanidins and uropathogenic bacteria anti-adhesion activity. Phytochemistry 66, 2281
2291. Huang, D., Ou, B., Prior, R.L., 2005. The chemistry behind antioxidant capacity assays. J. Agric. Food Chem. 53, 1841
1856. Ifesan, B.O.T., Olorunsola, B.O., Ifesan, B.T., 2015. Nutritional composition and acceptability of candy from avocado seed (Persea americana). Int. J. Agric. Innovations Res 3, 1732
1735. Imafidon, K.E., Amaechina, F.C., 2010. Effects of aqueous seed extract of Persea americana Mill (avocado) on blood pressure and lipid profile in hypertensive rats. Adv. Biol. Res. 4, 116
121. Isaac, A.T., Ganiyu, O., Akinyemi, A.J., Agani, R.A., Olanrewaju, B.O., 2014. Avocado pear fruits and leaves aqueous extracts inhibit α-amylase, α-glucosidase and snp induced lipid peroxidation
an insight into mechanisms involve in management of type 2 diabetes. Int. J. Appl. Nat. Sci. 3, 21
34. Iso, H., Stampfer, M.J., Manson, J.E., Rexrode, K., Hennekens, C.H., Colditz, G.A., et al., 1999. Prospective study of calcium, potassium, and magnesium intake and risk of stroke in women. Stroke 30, s1772
s1779. Jennings, L.K., 2009. Mechanisms of platelet activation: need for new strategies to protect against platelet-mediated atherothrombosis. Thromb. Haemost. 101, 248
257. Jime´nez-Arellanes, A., Luna-Herrera, J., Ruiz-Nicola´s, R., Cornejo-Garrido, J., Tapia, A., Ye´pez-Mulia, L., 2013. Antiprotozoal and antimycobacterial activities of Persea americana seeds. BMC Complement. Altern. Med. 13, 1
5. Keat Wei, L., Sutherland, H., Au, A., Camilleri, E., Haupt, L.M., Gan, S.H., et al., 2015. A potential epigenetic marker mediating serum folate and vitamin B12 levels contributes to the risk of ischemic stroke. Biomed. Res. Int. 2015, 167976
167980. Kim, O.K., Murakami, A., Nakamura, Y., Takeda, N., Yoshizumi, H., Ohigashi, H., 2000a. Novel nitric oxide and superoxide generation inhibitors, persenone A and B, from avocado fruit. J. Agri. Food Chem. 48, 1557
1563.

Avocado Chapter | 4

91

Kim, O.K., Murakami, A., Takahashi, D., Nakamura, Y., Torikai, K., Kim, H.W., et al., 2000b. An avocado constituent, persenone A, suppresses expression of inducible forms of nitric oxide synthase and cyclooxygenase in macrophages, and hydrogen peroxide generation in mouse skin. Biosci. Biotechnol. Biochem. 64, 2504
2507. Kimaru, S.K., Monda, E., Cheruiyot, R.C., Mbaka, J., Alakonya, A., 2018. Sensitivity of Colletotrichum gloeosporioides isolates from diseased avocado fruits to selected fungicides in Kenya. Adv. Agric. 2018, 3567161
3567167. Kosi´nska, A., Karama´c, M., Estrella, I., Herna´ndez, T., Bartolome´, B., Dykes, G.A., 2012. Phenolic compound profiles and antioxidant capacity of Persea americana Mill. peels and seeds of two varieties. J. Agric. Food Chem. 60, 4613
4619. Kristanti, C.D., Simanjuntak, F.P.J., Dewi, N.K.P.A., Tianri, S.V., Hendra, P., 2017. Anti-inflammatory and analgesic activities of avocado seed (Persea americana Mill.). J. Farm. Sai. Komunitas 14, 104
111. Kristanty, R.E., Suriawati, J., Sulistiyo, J., 2014. Cytotoxic activity of avocado seeds extracts (Persea americana Mill.). Int. Res. J. Pharm. 5, 557
559. Larijani, L.V., Ghasemi, M., Kenari, S.A., Naghshvar, F., 2013. Evaluating the effect of four extracts of avocado fruit on esophageal squamous carcinoma and colon adenocarcinoma cell lines in comparison with peripheral blood mononuclear cells. Acta Med. Iran. 52, 201
205. Lee, S.G., Yu, M.H., Lee, S.P., Lee, I.-S., 2008. Antioxidant activities and induction of apoptosis by methanol extracts from avocado. J. Korean Soc. Food Sci. Nutr. 37, 269
275. Lerman-Garber, I., Ichazo-Cerro, S., Zamora-Gonza´lez, J., Cardoso-Saldan˜a, G., Posadas-Romero, C., 1994. Effect of a high-monounsaturated fat diet enriched with avocado in NIDDM patients. Diabetes Care 17, 311
315. Li, Z., Wong, A., Henning, S.M., Zhang, Y., Jones, A., Zerlin, A., et al., 2013. Hass avocado modulates postprandial vascular reactivity and postprandial inflammatory responses to a hamburger meal in healthy volunteers. Food Funct. 4, 384
391. Li, S., Zhou, T., Li, C., Dai, Z., Che, D., Yao, Y., et al., 2014. High metastaticgastric and breast cancer cells consume oleic acid in an AMPK dependent manner. PLoS One 9, e97330
e97341. Loo, K.W., Gan, S.H., 2012. Folic acid supplementation is not the sole factor in determining neural tube defects: the possible role of autoantibodies.. Afr. J. Biotechnol. 11, 11767
11771. Lu, Q.Y., Arteaga, J.R., Huerta, S., Go, V.L.W., Heber, D., 2005. Inhibition of prostate cancer cell growth by an avocado extract: role of lipid-soluble bioactive substances. J. Nutr. Biochem. 16, 23
30. Lu, Q.Y., Zhang, Y., Wang, Y., Wang, D., Lee, R.P., Gao, K., et al., 2009. California Hass avocado: profiling of carotenoids, tocopherol, fatty acid, and fat content during maturation and from different growing areas. J. Agric. Food Chem. 57, 10408
10413. Lu, Y.C., Chang, H.S., Peng, C.F., Lin, C.H., Chen, I.S., 2012. Secondary metabolites from the unripe pulp of Persea americana and their antimycobacterial activities. Food Chem. 135, 2904
2909. Lye, H.S., Lee, Y.T., Ooi, S.Y., Teh, L.K., Lim, L.N., Wei, L.K., 2018. Modifying progression of aging and reducing the risk of neurodegenerative diseases by probiotics and synbiotics. Front. Biosci. (Elite edition) 10, 344
351. Malik, S., Wong, N.D., Franklin, S.S., Kamath, T.V., L’Italien, G.J., Pio, J.R., et al., 2004. Impact of the metabolic syndrome on mortality from coronary heart disease, cardiovascular disease, and all causes in United States adults. Circulation 110, 1245
1250. Manal, M.S.M.S., Sahar, S.A.S., 2013. Effects of bioactive component of kiwi fruit and avocado (fruit and seed) on hypercholesterolemic rats. World J. Dairy Food Sci. 8, 82
93. Martı´nez-Padilla, L.P., Franke, L., Xu, X.Q., Juliano, P., 2018. Improved extraction of avocado oil by application of sono-physical processes. Ultrason. Sonochem. 40, 720
726. Matsusaka, Y., Kawabata, J., Takanori, K., 2003. Antioxidative constituents in avocado (Persea americana Mill.) seeds. J. Jpn. Soc. Food Sci. Technol. 50, 550
552. Monika, P., Geetha, A., 2015. The modulating effect of Persea americana fruit extract on the level of expression of fatty acid synthase complex, lipoprotein lipase, fibroblast growth factor-21 and leptin—a biochemical study in rats subjected to experimental hyperlipidemia and obesity. Phytomedicine 22, 939
945. Monika, P., Geetha, A., 2016. Effect of hydroalcoholic fruit extract of Persea americana Mill. on high fat diet induced obesity: a dose response study in rats. Indian J. Exp. Biol. 54, 370
378. Morais, D.R., Rotta, E.M., Sargi, S.C., Schmidt, E.M., Bonafe, E.G., Eberlin, M.N., et al., 2015. Antioxidant activity, phenolics and UPLC
ESI (
)
MS of extracts from different tropical fruits parts and processed peels. Food Res. Int. 77, pp. 392
399. Moreno, A.O., Dorantes, L., Galı´ndez, J., Guzma´n, R.I., 2003. Effect of different extraction methods on fatty acids, volatile compounds, and physical and chemical properties of avocado (Persea americana Mill) oil. J. Agri. Food Chem. 51, 2216
2221. Mostert, M.E., Botha, B.M., Plessis, L.M.D., Duodu, K.G., 2007. Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide. J. Sci. Food Agric. 87, 2880
2885. Murakoshi, M., Takayasu, J., Kimura, O., 1989. Inhibitory effect of alpha-carotene on proliferation of the human neuroblastoma cell line. J. Natl. Cancer Inst. 81, 1649
1652. Naveh, E., Werman, M.J., Sabo, E., Neeman, I., 2002. Defatted avocado pulp reduces body weight and total hepatic fat but increases plasma cholesterol in male rats fed diets with cholesterol. J. Nutr. 132, 2015
2018. Nedd, G., Kurup, R., Ansari, A.A., Holder, K., 2015. Antimicrobial properties of the fruit pulp of three local fruits: Morinda citrifolia, Persea americana and Musa sapientum in Guyana. J. Biol. Nat. 3, 87
93. Oberlies, N.H., Rogers, L.L., Martin, J.M., McLaughlin, J.L., 1998. Cytotoxic and insecticidal constituents of the unripe fruit of Persea americana. J. Nat. Prod. 61, 781
785.

92

Valorization of Fruit Processing By-products

Oboh, G., Isaac, A.T., Akinyemi, A.J., Ajani, R.A., 2014. Inhibition of key enzymes linked to type 2 diabetes and sodium nitroprusside induced lipid peroxidation in rats’ pancreas by phenolic extracts of avocado pear leaves and fruit. Int. J. Biomed. Sci. 10, 208
216. Okwu, D.E., Morah, F.N.I., 2007. Isolation and characterization of flavanone glycose 4, 5, 7-trihydroxyflavanone rhamnoglucose from Garcina kola seed. J. Appl. Sci. 7, 306
309. Ovesna´, Z., Vacha´lkova´, A., Horva´thova´, K., 2004. Taraxasterol and beta-sitosterol: new naturally compounds with chemoprotective/chemopreventive effects. Neoplasma 51, 407
414. Padmanabhan, M., Arumugam, G., 2014. Effect of Persea americana (avocado) fruit extract on the level of expression of adiponectin and PPAR-γ in rats subjected to experimental hyperlipidemia and obesity. J. Complement. Integr. Med. 11, 107
119. Pagliaccia, D., Pond, E., McKee, B., Douhan, G.W., 2013. Population genetic structure of Phytophthora cinnamomi associated with avocado in California and the discovery of a potentially recent introduction of a new clonal lineage. Phytopathology 103, 91
97. Palomer, X., Pizarro-Delgado, J., Barroso, E., Va´zquez-Carrera, M., 2017. Palmitic and oleic acid: the yin and yang of fatty acids in type 2 diabetes mellitus. Trends Endocrinol. Metab. 29, 178
190. Panchal, A.R., Berg, K.M., Kudenchuk, P.J., Del Rios, M., Hirsch, K.G., Link, M.S., 2018. 2018 American Heart Association Focused update on advanced cardiovascular life support use of antiarrhythmic drugs during and immediately after cardiac arrest: an update to the American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 138 (23), e740
e749. Paul, R., Kulkarni, P., Ganesh, N., 2011. Avocado fruit (Persea americana Mill) exhibits chemo-protective potentiality against cyclophosphamide induced genotoxicity in human lymphocyte culture. J. Exp. Ther. Oncol. 9, 221
230. Peou, S., Milliard-Hasting, B., Shah, S.A., 2016. Impact of avocado-enriched diets on plasma lipoproteins: a meta-analysis. J. Clin. Lipidol. 10, 161
171. Pieterse, Z., 2003. Avocados (monounsaturated fatty acids), weight loss and serum lipids. Energy (kJ) 26, 65
71. Prochazkova, D., Bousova, I., Wilhelmova, N., 2011. Antioxidant and prooxidant properties of flavonoids. Fitoterapia 82, 513
523. Qin, X., Zhong, J., 2016. A review of extraction techniques for avocado oil. J. Oleo Sci. 65, 881
888. Raharjo, S.H.T., Witjaksono, N.F.N., Gomez-Lim, M.A., Padilla, G., Litz, R.E., 2008. Recovery of avocado (Persea americana Mill.) plants transformed with the antifungal plant defensing gene PDF1.2. In Vitro Cell Dev. Biol. Plant. 44, 254
262. Rao, U.S.M., Adinew, B., 2011. Remnant β-cell-stimulative and anti-oxidative effects of Persea americana fruit extract studied in rats introduced into Streptozotocin-induced hyperglycaemic state. Afr. J. Tradit. Complement. Altern. Med. 8, 210
217. Reddy, M., Moodley, R., Jonnalagadda, S.B., 2012. Fatty acid profile and elemental content of avocado, Persea americana Mill. Oil-effect of extraction methods. J. Environ. Sci. Health B 47, 529
537. Rimando, A.M., Perkins-Veazie, P.M., 2005. Determination of citrulline in water melon rind. J. Chromatogr. A 1078, 196
200. Rodrı´guez-Carpena, J.G., Morcuende, D., Andrade, M.J., Kylli, P., Este´vez, M., 2011a. Avocado (Persea americana mill.) Phenolics, in vitro antioxidant activities, and inhibition of lipid and protein oxidation in Porcine Patties. J. Agric. Food Chem. 59, 5625
5635. Rodrı´guez-Carpena, J.G., Morcuende, D., Este´vez, M., 2011b. Avocado by-products as inhibitors of color deterioration and lipid and protein oxidation in raw porcine patties subjected to chilled storage. Meat Sci. 89, 166
173. Rodrı´guez-Sa´nchez, D., Silva-Platas, C., Rojo, R.P., Garcı´a, N., Cisneros-Zevallos, L., Garcı´a-Rivas, G., et al., 2013. Acitivity-guided identification of acetogenins as novel lipophilic antioxidants present in avocado pulp (Persea americana). J. Chromatogr. B. 942
943, 37
45. Rodriguez-Sanchez, D.G., Flores-Garcı´a, M., Silva-Platas, C., Rizzo, S., Torre-Amione, G., De la Pen˜a-Diaz, A., et al., 2014. Isolation and chemical identification of lipid derivatives from avocado (Persea americana) pulp with antiplatelet and antithrombotic activities. Food Funct. 6, 192
202. Rosenblat, G., Meretski, S., Segal, J., 2010. Polyhydroxylated fatty alcohols derived from avocado suppress inflammatory response and provide nonsunscreen protection against UV-induced damage in skin cells. Arch. Dermatol. Res. 303, 1
8. Rotta, E.M., Rodrigues, D., Biondo, F., Batoqui, P., Jorge, V., Vergilio, J., 2016. Use of avocado peel (Persea americana) in tea formulation: a functional product containing phenolic compounds with antioxidant activity. Acta Sci. Technol. 38, 23
29. Saavedra, J., Co´rdova, A., Navarro, R., Dı´az-Caldero´n, P., Fuentealba, C., Astudillo-Castro, C., et al., 2017. Industrial avocado waste: functional compounds preservation by convective drying process. J. Food Eng. 198, 81
90. Salinas-Salazar, C., Herna´ndez-Brenes, C., Rodrı´guez-Sa´nchez, D.G., Castillo, E.C., Navarro-Silva, J.M., Pacheco, A., 2016. Inhibitory activity of avocado seed fatty acid derivatives (acetogenins) against Listeria monocytogenes. J. Food Sci. 82, 134
144. Samson, J.A., 1991. Aguacate. Fruticultura Tropical. Limusa, Ciudad de Me´xico, pp. 281
303. Serbinova, E., Chop, Y.M., Packer, J., 1992. Distribution and antioxidant activity of a palm oil carotene fraction in rats. Biochem. Intern. 28, 881
886. Sharma, R., Vikrant, A., 2011. A review on fruits having anti-diabetic potential. J. Chem. Pharm. Res. 3, 204
212. Shehata, M.M.S.M., Soltan, S.S., 2013. Effects of bioactive component of kiwi fruit and avocado (fruit and seed) on hypercholesterolemic rats. World J. Dairy Food Sci. 8, 82
93. Song, Y., Manson, J.E., Buring, J.E., Sesso, H.D., Liu, S., 2005. Association of dietary flavonoids with risk of type 2 diabetes, and markers on insulin resistance and systemic inflammation in women: a prospective study and cross sectional analysis. J. Am. College Nutr. 24, 376
384. Soong, Y.Y., Barlow, P.J., 2004. Antioxidant activity and phenolic content of selected fruit seed. Food Chem. 88, 411
417. Steffel, J., Verhamme, P., Potpara, T.S., Albaladejo, P., Antz, M., Desteghe, L., et al., 2018. The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation. Eur. Heart J. 39, 1330
1393. Sudhir, K., 2005. Lipoprotein-associated phospholipase A2, a novel inflammatory biomarker and independent risk predictor for cardiovascular diseases. J. Clin. Endocrinol. Metab. 90, 3100
3105.

Avocado Chapter | 4

93

Sun, H., Ge, X., Lv, Y., Wang, A., 2012. Application of accelerated solvent extraction in the analysis of organic contaminants, bioactive and nutritional compounds in food and feed. J. Chromatogr. A 1237, 1
23. Tabeshpour, J., Razavi, B.M., Hosseinzadeh, H., 2017. Effects of Avocado (Persea americana) on metabolic syndrome: a comprehensive systematic review. Phytother. Res. 31, 819
837. The IUCN Red List of Threatened Species TM: Persea Americana, 2017. Available from: ,http://www.iucnredlist.org/details/96986556/0.. United States Department of Agriculture (USDA), 2018. National nutrient database for standard reference: release April. The National Agricultural Library. Available from: ,https://ndb.nal.usda.gov/ndb/foods/show/301058?manu 5 &fgcd 5 &ds 5 &q 5 Avocados,%20raw,%20all%20commercial%20varieties.. Venkateswaran, V., Fleshner, N.E., Klotz, L.H., 2002. Modulation of cell proliferation and cell cycle regulators by vitamin E in human prostate carcinoma cell lines. J. Urol. 168, 1578
1582. Villa-Rodrı´guez, J.A., Molina-Corral, F.J., Ayala-Zavala, J.F., Olivas, G.I., Gonza´lez-Aguilar, G.A., 2011. Effect of maturity stage on the content of fatty acids and antioxidant activity of ‘Hass’ avocado. Food Res. Int. 44, 1231
1237. Vinha, A.F., Moreira, J., Barreira, S.V., 2013. Physicochemical parameters, phytochemical composition and antioxidant activity of the algarvian avocado (Persea Americana Mill.). J. Agric. Sci. 5, 100
109. Wang, W., Bostic, T.R., Gu, L., 2010. Antioxidant capacities, procyanidins and pigments in avocados of different strains and cultivars. Food Chem. 122, 1193
1198. Wang, L., Bordi, P.L., Fleming, J.A., Hill, A.M., Kris-Etherton, P.M., 2015. Effect of a moderate fat diet with and without avocados on lipoprotein particle number, size and subclasses in overweight and obese adults: a randomized, controlled trial. J. Am. Heart Assoc. 4, e001355. Wei, L.K., Au, A., Menon, S., Gan, S.H., Griffiths, L.R., 2015. Clinical relevance of MTHFR, eNOS, ACE, and ApoE gene polymorphisms and serum vitamin profile among Malay patients with ischemic stroke. J. Stroke Cerebrovasc. Dis. 24, 2017
2025. Wien, M., Haddad, E., Oda, K., Sabate´, J., 2013. A randomized 3 3 3 crossover study to evaluate the effect of Hass avocado intake on post-ingestive satiety, glucose and insulin levels, and subsequent energy intake in overweight adults. Nutr. J. 12, 1
9. Williams, A.W., Boileau, T.W., Zhou, J.R., Clinton, S.K., Erdman, J.J.W., 2000. Beta-carotene modulates human prostate cancer cell growth and may undergo intracellular metabolism to retinol. J. Nutr. 130, 728
732. Wong, X., Carrasco-Pozo, C., Escobar, E., Navarrete, P., Blachier, F., Andriamihaja, M., et al., 2016. Deleterious effect of p-cresol on human colonic epithelial cells prevented by proanthocyanidin-containing polyphenol extracts from fruits and proanthocyanidin bacterial metabolites. J. Agric. Food Chem. 64 (18), 3574
3583.

Further reading Dabas, D., Shegog, R.M., Ziegler, G.R., Lambert, J.D., 2013. Avocado (Persea americana) seed as a source of bioactive phytochemicals. Curr. Pharm. Des. 19, 6133
6140.

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Chapter 5

Berries Petras Rimantas Venskutonis Department of Food Science and Technology, Kaunas University of Technology, Kaunas, Lithuania

Chapter Outline 5.1 Introduction 5.2 Composition of berry pomace 5.2.1 Cell wall polysaccharides, proteins, and minerals 5.2.2 Berry pomace and seed oil 5.2.3 Phytochemical composition and bioactivities of pomace 5.3 Processing of berry pomace 5.3.1 Postpressing preparation of berry pomace for processing 5.3.2 Extraction of various constituents from berry pomace

96 97 97 99 102 108 108 109

5.4 Application of berry pomace products 5.4.1 Applications of dried berry pomace 5.4.2 Applications of berry pomace extracts 5.4.3 Encapsulation of pomace ingredients 5.5 Conclusion Acknowledgments References Further reading

116 117 118 119 120 120 120 125

Abbreviations AAE ABTS AIS CEs CyGE DM DP DPPH DW EAE FRAP GAEs MAE ORAC PLE PUFAs QEs SE SFE TEs TMAs TPC UAE

ascorbic acid equivalents 2,20 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) alcohol insoluble fiber catechin equivalents cyannidin-3-glucoside equivalents dry matter degree of polymerization 2,2-diphenyl-1-picrylhydrazyl dry weight enzyme-assisted extraction ferric reduction antioxidant power gallic acid equivalents microwave-assisted extraction oxygen radical absorbance capacity pressurized liquid extraction polyunsaturated fatty acids quercetin equivalents Soxhlet extraction supercritical fluid extraction Trolox equivalents total monomeric anthocyanins total phenolic content ultrasound-assisted extraction

Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00005-8 © 2020 Elsevier Inc. All rights reserved.

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5.1

Valorization of Fruit Processing By-products

Introduction

Fruits and vegetables have always been recognized as important parts of healthy diets, mainly due to the presence of bioactive phytochemicals, vitamins, dietary fiber, and minerals. Many of them may be consumed as fresh foods, however due to a short shelf life significant parts of fruits and vegetable harvests are processed into various products that are more durable for storage. Extensive studies on the evaluation of the nutritional value of by-products and waste, which are generated during processing of plant foods, as well as the possibilities of converting them into higher added-value ingredients started approximately 30 years ago. For instance, the first publications with search words “fruit 1 pomace” in Clavirate Analytics Web of Science (CA-WoS) appeared in 1990, while currently (accessed on February 2, 2019) 1454 records with these words are available in this database. The largest number of investigations focused on the most commercially important crops such as citrus fruits, apples, and grapes; however, more recently the results on the pomaces of a remarkably large number of edible and less known fruits have been reported. Many of these studies are aimed at the recovery of bioactive phytochemicals, oil, pectin, and other valuable substances from fruits, vegetables, cereals, sugar beet, and sugar cane (Schieber et al., 2001). Laufenberg et al. (2003) published the first comprehensive review on the transformation of vegetable waste into value-added products, based on a holistic concept of food production. The authors demonstrated that clean production goals may be achieved by (1) upgrading vegetable residues for the production of novel multifunctional ingredients; (2) bioconversion via solid-state fermentation (SSF); and (3) conversion into operating supplies such as bioadsorbents for wastewater treatment. The interest in efficient recovery of vegetable phytochemicals increased due to rapidly growing scientific evidence demonstrating the role of plant secondary metabolites in food and their potential effects on human health. Commonly berries are briefly defined as small and pulpy fruits, although the scientific usage of the term berry differs from the common usage. Many berry species are edible and may be consumed as fresh foods, although some berry fruits are poisonous. In general, many berry species are very rich in dietary phenolic antioxidants, mainly belonging to flavonoids and phenolic acids. However, the content of phenolics as well as the proportions of different classes of these constituents in different berry types is quite variable, as has been reported in many articles, for example, in the study of Ha¨kkinen et al. (1999) who characterized flavonoids and phenolic acids in the berries of 19 plant species. Thus flavonols were the prevailing group of phenolics in cranberries, lingonberries, sea buckthorn berries, and crowberries; hydroxycinnamic acids were dominant in blueberries and bilberries; strawberries, cloudberries, red raspberries, and Arctic brambles were particularly rich in ellagic acid. The highest value of total phenolic content (TPC) among lyophilized seedless berries was determined for blueberries [ . 300 mg/100 g dry weight (DW)], while the lowest was found in currants and gooseberries, ,50 mg/100 g DW (Ha¨kkinen et al., 1999). Moreover, the content and the composition of phenolic compounds may be quite variable even within the same species, for example, as was demonstrated for the cultivars of raspberries (Bobinait˙e et al., 2012, 2016a), blueberries (Kraujalyt˙e et al., 2015), guelder-rose (Kraujalyt˙e et al., 2013), berries, and black currants (Bakowska-Barczak et al., 2009). The health benefits of the phytochemicals belonging to different classes of polyphenols have been demonstrated in numerous studies. The majority of berries are rapidly perishable fruits and therefore large parts of their harvests are dried, frozen, or processed into other, longer shelf life products such as jams, purees, preserves, and juice. Some processing technologies, particularly the pressing of juice, generate large amounts of by-products. Juice, which is prepared mainly by mechanically squeezing berry flesh without the application of heat or solvents, is one of the most important products of some berry species. The residues remaining after the separation of juice are called pomace, marc, or press cake, however the former term is most widely used in the scientific and technical literature. Berry pomace contains the skins, pulp, seeds, and stems of the fruit. Considerable amounts of seeds and skins containing nutritionally valuable substances are discarded after pressing juice from fruits and berries. Berry seeds contain high amounts of polyunsaturated fatty acids (PUFAs) rich oils, and other valuable lipophilic compounds, while other pomace parts are rich in polyphenolic antioxidants and cell wall dietary fiber. Currently large amounts of berry pomace are still discarded as waste or used for composting and animal feeding. Numerous reports outline that substantial amounts of important nutrients, especially cell wall
bound phenolic compounds, are retained in pomace and could be recovered by employing various extraction and fractionation technologies (Kammerer et al., 2014; Wijngaard et al., 2012; Galanakis, 2012, 2013). Upgrading vegetable residues for the production of novel ingredients, which may find applications as food additives and valuable ingredients for functional foods and nutraceuticals, is regarded as a promising trend in developing clean production processes and achieving the zero-waste society target set by the European Union for 2025 (Naziri et al., 2014). Consequently there is a great interest in the recovery of valuable phytochemicals and other substances from berry pomace for their applications in foods and other products. The reports on berry pomace are less numerous than on the pomace of fruits and vegetables in general; 183 records are available in CA-WoS containing a combination of the search words “berry 1 pomace.” One of the first reports

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related to the processing of berry pomace focused on resveratrol in muscadine berries, juice, pomace, purees, seeds, and wines (Ector et al., 1996). This chapter focuses on valorization of the pomace of various berries commonly used for human nutrition, excluding grapes and strawberries because various aspects of wine pomace have been reviewed in several articles, some of them very recent (Peixoto et al., 2018; Muhlack et al., 2018; Yammine et al., 2018; Beres et al., 2017; Garcia-Lomillo and Gonzalez-San Jose, 2017), while valorization of strawberry pomace is discussed in another chapter of this book. Grape pomace has traditionally been used to produce pomace brandy such as grappa, orujo, to¨rko¨lypa´linka, and zivania, while nowadays it is mostly used as fodder, as fertilizer, or for extracting bioactive compounds (Aizpurua-Olaizola et al., 2015). It should be noted that there is some confusion regarding botanical and common names of various berry species; the same type of berries have different names in different regions or even countries. The berries covered in this chapter are listed in Table 5.1.

5.2

Composition of berry pomace

Berry pomaces are generated during the comparatively simple process of mechanical pressing. However, the effectiveness of the equipment and process parameters may produce juice and pomace of different composition. In addition, some technologies use enzymatic treatment for increasing juice yield and such treatments may also change the redistribution of some berry constituents between the juice and the pomace, as well as influence their properties. For instance, industrial enzymes Pectinex and Rohapect, which were used as the aids in pressing sour cherry, increased the yield of juice by up to 6%; the yield of alcohol insoluble fiber (AIS) for fruits of Kelleriis and Dobreczyn Botermo varieties was lower than 10% (Kosmala et al., 2009). Econase, Pectinex Ultra SP-L, Pectinex Smash, Pectinex BE 3-L, and Biopectinase CCM preparations improved bilberry and black currant juice yield and increased the total content of anthocyanins by 13%
41%, leaving lower amounts of these compounds in the pomace (Buchert et al., 2005). In general, a larger part of water-soluble substances, such as monosugars, soluble pectin, organic acids, and vitamin C, occurs in the juice, while water-insoluble fractions, for example, cell wall polysaccharides, proteins, and lipids, remain in the press residue, which is a quite heterogeneous material composed of skin, pulp, and seeds. The redistribution of polyphenolic phytochemicals between juice and pomace is rather complicated due to the differences in their solubility in water and the state in the complex berry matrix; some polyphenolics may be strongly bound to the cell walls. Therefore comprehensive evaluation of berry pomace composition and properties is very important for developing cost-effective processing schemes and technologies for their valorization. Berry pomace substances may be grouped into macro- and microcomponents, lipophilic and hydrophilic compounds, as well as into monomeric, oligomeric molecules, and biopolymers. For instance, cell wall polysaccharides have been most widely studied as the main bulk constituents, while polyphenolics were intensively investigated as the most important microcomponents of berry pomace.

5.2.1

Cell wall polysaccharides, proteins, and minerals

Plant cell walls are very complex structures constituted of various polysaccharides, lignin, and proteins as the major components. From the nutritional point of view, nondigestible polysaccharides and lignin are referred as dietary fiber; their yields as well as the composition may highly depend on the berry pretreatment and analysis procedures, for example, extraction methods, enzymatic, thermal, or chemical hydrolysis. Dietary fibers for nutritional purposes are also divided into water-soluble and water-insoluble substances. Therefore the information on qualitative and quantitative composition of berry cell walls, which is available from various reports, may differ significantly. McDougall and Beames (1994) evaluated the nutritive value of raspberry pomace as a possible feed for monogastric animals; on average it contained [on dry matter (DM) basis] 11.1% crude fat, 10.0% crude protein, 59.5% total dietary fiber, 46.0% acid detergent fiber, 11.7% lignin, 6.0% cutin, 2.2% acid detergent ash, 26.9% cellulose, and 25.13 MJ/kg gross energy. Pieszka et al. (2015) also investigated berry pomace as a source of antioxidants and nutraceuticals in the animal diet and determined the following content of different components in black currant/chokeberry pomaces (in %): crude ash (3.49/1.95), proteins (12.76/10.77), crude fat (10.52/5.15), crude fiber (20.18/21.79), neutral detergent fiber (38.81/34.65), acid detergent fiber (34.36/35.59), lignin (13.13/17.58), and soluble sugars (2/0.35). Black currant proteins were rich in proline, lysine, and cysteine; black currant and chokeberry pomace contained valuable mineral elements: K (4.28 and 2.78 g/kg), Ca (3.32 and 2.75 g/kg), P (92.97 and 2.39 g/kg), Mg (0.85 and 0.88 g/kg), Fe (244 and 197 mg/kg), Mn (18.9 and 31.5 mg/kg), Zn (17.4 and 15.7 mg/kg), and Cu (7.99 and 1.95 mg/kg) (Pieszka et al., 2015). Black currant, sour cherry, and raspberry pomaces, which were used in muffin formula, contained 6.9%, 7.6%, and 8.7% (w/w) proteins, 38.5%, 24.4%, and 54.2% total dietary fiber (TDF), respectively (Go´rna´s et al., 2016).

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TABLE 5.1 The list of berry species covered in the chapter. Botanical name

Common names

Vaccinium spp.a

Blueberry (different spp., e.g., most widely cultivated highbush blueberry) (V. corymbosum)

Vaccinium myrtillus L.

Bilberry (sometimes called “wild blueberry”)

Vaccinium uliginosum L.

Bog bilberry, bog blueberry, bog whortleberry, bog huckleberry, northern bilberry, ground hurts

Vaccinium vitis-idaea L.

Lingonberry, partridgeberry or cowberry b

Vaccinium oxycoccos L.

Cranberry (small cranberry, bog cranberry, swamp cranberry)

Vaccinium macrocarpon L.

American cranberry

c

Blackberry

Rubus spp.

Rubus idaeus L.

Raspberry c

Rubus spp., R. fruticosus species aggregate

Black raspberry

A cross among Rubus idaeus, R. fruticosus, R. aboriginum, and R. 3 loganobaccusd

Boysenberry

Rubus chamaemorus L.

Cloudberry

Rubus spp. L.

Caneberries

Rubus L. subgenus Rubus

Marionberry, Marion blackberry

Rubus glaucus Benth

Andes berry

Ribes nigrum L.

Black currant

Ribes rubrum L.

Red currant, white currant

Ribes uva-crispa L.

Gooseberry

Ribes nidrigolaria Bauer.

Jostaberry

Aronia melanocarpa (Michx.) Elliotte

Chokeberry

Hippophae rhamnoides L.

Sea buckthorn berry

Morus nigra L.

Black mulberry or blackberryf

Empetrum nigrum L.

Crowberry

Viburnum opulus L.

Guelder-rose berry

Physalis peruviana L.

Goldenberry

Eugenia brasiliensis Lam

Grumichama (a little sweet cherry)

Sambucus nigra L.

Black or European elderberry

Sambucus ebulus L.

Dwarf elderberry or danewort

a

V. alaskaense, V. angustifolium, V. boreale, V. caesariense, V. corymbosum, V. constablaei, V. consanguineum, V. darrowii, V. elliottii, V. formosum, V. fuscatum, V. hirsutum, V. myrsinites, V. myrtilloides, V. operium, V. pallidum, V. simulatum, V. tenellum, V. virgatum (syn. V. ashei). V. erythrocarpum, V. macrocarpon, V. microcarpum. c R. ursinus, R. laciniatus, R. argutus, R. armeniacus, R. plicatus, R. ulmifolius, R. allegheniensis. d R. leucodermis, R. occidentalis, R. coreanus. e Also Aronia arbutifolia (L.) Pers. Aronia prunifolia (Marshall) Rehder. f Not to be confused with the blackberries belonging to various Rubus spp. b

Nawirska and Kwa´sniewska (2005) determined different types of dietary fiber in black currant, chokeberry, and cherry pomaces: pectin occurred in the smallest amounts, and the content of lignin was very high (black currant and cherry) or comparatively high (chokeberry). The following percentage proportions of pectin, cellulose, hemicellulose, and lignin were reported in the analyzed berry pomaces: 1.51%, 10.7%, 18.4%, 69.4% (cherry); 7.85%, 33.5%, 34.6%, 24.1% (chokeberry); 2.73%, 25.3%, 12.0%, 59.3% (black currant), respectively (Nawirska and Kwa´sniewska, 2005).

Berries Chapter | 5

99

Later So´jka and Kro´l (2009) comprehensively characterized the composition and the properties of seedless industrial dried black currant pomace from two subsequent harvest seasons, which were separated into ,0.8, 2
5, and .5 mm particle size fractions; some characteristics were highly dependent on pomace fraction and berry harvest year. Mokhtar et al. (2018) reported that goldenberry waste powder contained 5.87% moisture, 15.89% protein, 13.72% fat, 3.52% ash, 16.74% dietary fiber, and 61% carbohydrates; the main mineral elements were K, Na, and P at 560, 170, and 130 mg/100 g, respectively; cysteine/methionine, histidine, and tyrosine/phenylalanine were quantitatively important amino acids. Hilz et al. (2005) characterized black currant and bilberry pomace cell wall polysaccharides regarding their composition in skin, pulp, and seeds as well as the extractability and isolation from juice and press cakes. The amount of AIS in press cake was almost similar (34% and 36%), however their degrees of methylation and acetylation were different, 24%/52% and 58%/38%, respectively. Glucose was the main sugar in AIS of black currant and bilberry pomace (34 mol.% vs 41 mol.%), however black currant AIS had more mannose (24 mol.%) and galacturonic acid (20 mol.%), while bilberry AIS contained higher amounts of xylose (33 mol.%) (Hilz et al., 2005). The amount of proteins was 17% in both pomaces. Hilz et al. (2006) extended their study by identifying and quantifying rhamnogalacturonan II (RGII) in bilberry and black currant juice and pomace via its diagnostic sugar residues; juice contained the free RGII dimer, while it was released from the pomace by the enzymatic degradation of homogalacturonan. When enzymes were used as juice processing aids, the yields of AIS and TDF from sour cherry pomace decreased for all three tested varieties, except for Kelleriis treated with Pectinex where the yields were found to be increased (Kosmala et al., 2009). In addition, the authors fractionated cell wall polysaccharides into water-soluble, chelating agent-soluble, diluted alkali-soluble pectin, concentrated alkali-soluble polysaccharides, and water residue. Glucose (from cellulose), galacturonic acid, and arabinose were the main monomers in sour cherry cell wall polysaccharides; their contents in various pomace fractions were 440
747, 13
550, and 17
168 mg/g. Kosmala et al. (2010) also investigated sugar composition in cell walls of black currant pomace with or without solvent extraction of polyphenols and reported that solvent treatments increased the content of AIS; ethanol increased their swelling and water-binding capacity, while acetone had decreasing effects on these characteristics. The content of sucrose, glucose, fructose, and sorbitol in different chokeberry pomace fractions was in the ranges of 0.03%
0.43%, 0.39%
0.89%, 0.48%
0.58%, and 1.06%
2.32% DW (So´jka et al., 2013). So´jka et al. (2013) applied mechanical processes for pomace prefractionation as the simplest methods for obtaining the products with different composition. They divided dried black chokeberry pomace into six fractions on the basis of their granulation and by air separation and obtained the products with different composition (in DM): TDF, 63.9%
77.9%; proteins, 4.9%
24.1%; fat, 3.1%
13.9%; ash, 1.4%
3.9%; Ca, 2.19%
4.08%; K, 1.81%
3.08%; Mg, 0.37%
2.5%; Na, 52.5
89.0 mg/kg; Fe, 68.9
86.2 mg/kg; Zn, 5.6
36.9 mg/kg; Cu, 5.0
12.4 mg/kg. The air separated fraction from the pomace with seeds contained the highest amount of proteins, fat, and ash, while the highest content of TDF was in .2 mm agglomerates.

5.2.2

Berry pomace and seed oil

Berry oils and lipophilic microconstituents are present mainly in their seeds. Consequently the overwhelming part of these constituents after the pressing of juice remains in the pomace. Two approaches have been used in the recovery of oil and other lipophilic compounds from berry pomace and for investigating their composition: (1) the whole press residue and (2) mechanically separated seeds. For analytical purposes the lipids were extracted by standard methods with nonpolar organic solvents, mainly hexane, while for technological purposes more environment- and food-friendly methods are preferred, namely pressing or supercritical fluid extraction with carbon dioxide (SFE-CO2). Cold pressing is a simple method, which is performed without using solvents; however, pressed oil recoveries usually are not high; for instance sea buckthorn seed oil recoveries were 65.1% and 41.2% for SFE-CO2 (45 C and 35 MPa) and screw pressing, respectively (Yakimishen et al., 2005). Pressed grapeseed oil is a well-known commercial product, while other berry oils are produced by some companies on a very small scale. Berry seed oils are composed mainly of health-beneficial oleic acid and PUFA. For instance, the sum of linoleic and α-linolenic acids in commercially produced by Fruit Smart, Inc. pressed blackberry, black raspberry, and blueberry seed oils was 79.9%, 67.4%, 70.6%, respectively (Li et al., 2016a); linoleic acid was predominant in goldenberry waste powder followed by oleic, palmitic, and stearic acids (Mokhtar et al., 2018). The differences in fatty acid composition of berry pomace and/or seed oils extracted by different methods usually are not significant; however, remarkable variations for the same berry species may be observed between different studies (Table 5.2). Black currant seed oil contains an exceptionally high percentage of γ-linolenic acid, up to 17% (Oktay Basegmez et al., 2017; Bakowska-Barczak et al., 2009), while other Ribes spp., namely red currant, gooseberry, and jostaberry oils also contained remarkable

TABLE 5.2 The yields of lipids and composition of fatty acids of berry pomace (P) and seeds (S), in %. Pomace

Part

18:1n-9

18:2n-6

18:3n-3

Ni

3.3

1.6

14.4

63.4

16.5

Li et al. (2016a)

4.6

2.8

19.2

61.6

15.0

Radoˇcaj et al. (2014)

P

11.8

3.7

4.7

13.9

42.3

15.4

Wajs-Bonikowska et al. (2017)

P

11.4

4.2

2.1

12.1

47.3

10.6

Wajs-Bonikowska et al. (2017)

S

Blackberry

P

Blackberryc Blackberry

a

Black raspberry

Ref.

18:0

b

d

Fatty acids 16:0

a

Blackberry

Yield

18:3n-6

S

Ni

2.0

0.6

9.7

53.4

33.7

Li et al. (2016a)

a

S

Ni

5.2

1.3

22.2

41.9

28.1

Li et al. (2016a)

e

S

5.7

2.8

22.9

43.5

25.1

Parry et al. (2005)

Blueberry Blueberry

f

Blueberry

P

2.80

7.64

3.31

50.74

30.0

7.06

Dulf et al. (2012)

g

Sea buckthorn

S

Ni

18.0

1.9

20.3

37.4

29.0

Yang et al. (2011)

Sea buckthornh

S

30
33

,1

5
7

30

35

´ Zielinska and Nowak (2017) Stoica-Guzun et al. (2018)

i

Sea buckthorn

S

13.7

7.9

2.8

22.7

38.9

26.8

g

S

Ni

5.7

1.5

13.4

46.1

13.6

15.0

Yang et al. (2011)

g

P

14.6

6.4

1.5

11.8

46.9

13.8

14.0

Oktay Basegmez et al. (2017)

b

P

6.0

1.5

11.8

47.2

13.9

14.1

Oktay Basegmez et al. (2017)

j

S

17.6

7.66

1.71

10.87

43.27

14.89

12.33

Piskernik et al. (2018)

k

Black currant

S

14.5

6.5

1.6

10.2

49.1

13.4

13.9

Dobson et al. (2012)

Black currantk

P

7.8

8.6

1.6

9.8

45.6

12.6

11.4

Dobson et al. (2012)

l

S

27.1
32.8

5.8
6.6

1.5
1.9

11.0
12.3

43.9
47.5

14.1
18.1

10.9
16.7

Bakowska-Barczak et al. (2009)

m

Black currant

P

10.52

12.11

1.66

10.47

41.56

15.17

8.01

Pieszka et al. (2015)

g

S

Ni

3.9

1.5

17.9

41.4

22.3

8.8

Yang et al. (2011)

5.24

Piskernik et al. (2018)

Black currant Black currant Black currant Black currant

Black currant

Red currant j

Red currant

S

20.7

5.39

1.78

16.49

35.41

24.40

Raspberry

g

S

Ni

2.6

0.9

11.3

55.4

28.8

Yang et al. (2011)

Raspberry

b

P

3.3

2.1

13.0

55.8

33.0

Radoˇcaj et al. (2014)

Raspberryg

P

14.6

2.3

0.8

12.7

48.7

34.4

Kryˇzeviˇciut˙ ¯ e et al. (2016)

Raspberry

e

S

1.3

1.0

12.4

53.0

32.4

Parry et al. (2005)

Raspberry

f g

Cloudberry

P

7.00

2.61

1.19

26.22

51.07

17.93

Dulf et al. (2012)

S

Ni

3.3

1.6

17.8

43.6

29.8

Yang et al. (2011)

Bilberryg

S

Ni

4.5

1.1

21.8

35.9

36.1

Yang et al. (2011)

Bilberryf

P

3.93

6.99

1.51

47.93

33.71

8.07

Dulf et al. (2012)

S

Ni

5.2

1.0

23.6

35.3

34.3

Yang et al. (2011)

S

Ni

4.8

1.2

23.4

35.0

34.6

Yang et al. (2011)

S

Ni

3.0

1.3

13.7

42.5

37.4

Yang et al. (2011)

P

3.75

3.28

0.68

50.44

36.25

8.22

Dulf et al. (2012)

Eur. rowanberry

S

Ni

7.1

1.3

26.6

62.4

0.8

Yang et al. (2011)

g

Snowball berry

S

Ni

1.6

0.7

45.7

50.1

0.7

Yang et al. (2011)

Lingonberryg

S

Ni

1.0

0.2

19.3

34.1

44.8

Yang et al. (2011)

S

17.9

8.12

1.61

14.32

33.86

20.54

8.48

Piskernik et al. (2018)

S

22.4

8.48

1.83

13.55

31.17

28.01

7.87

Piskernik et al. (2018)

P

21.41

8.46

2.40

14.28

37.16

36.05

Dulf et al. (2015)

P

22.2

7.70

2.78

20.22

43.11

237.8

Dulf et al. (2015)

3.3

3.1

15.1

62.8

15.8

Parry et al. (2005)

Cranberry

g g

Arctic cranberry g

Crowberry f

Cowberry

g

j

Gooseberry j

Jostaberry

n

Black elderberry

n

Dwarf elderberry Marionberry

e

S

Boysenberry

e

S

4.2

4.5

18.0

53.8

19.5

Parry et al. (2005)

P

5.50

7.22

1.37

23.47

64.67

0.34

Dulf et al. (2012)

m

P

5.15

8.60

1.98

17.42

63.97

3.08

Pieszka et al. (2015)

n

P

10.09

16.02

7.80

14.48

46.81

3.47

Dulf et al. (2018)

Chokeberryf Chokeberry Chokeberry

P, whole pomace; S, seeds. a Commercially produced by Fruit Smart, Inc. by pressing. b Extracted with hexane for 8 h. c Hexane extract. d SFE-CO2 extract. e Produced by Badger Oil Company by cold pressing. f Extracted with methanol/chloroform from fresh wet pomace and total lipids expressed on wet pomace basis. g SFE-CO2 of the seeds separated from dried pomace mechanically by wind-screening. h Contains 30%
35% C16:1. i Mean values for the pomace without and with pretreatment by ultrasonication or freezing. j Oil extracted with petroleum ether by Weibull and Stoldt method; mean values from 10 black currant, four red currant, five gooseberry and one jostaberry samples. k Extracted with isohexane. l From five cultivars: Ben tiran, Ben Sarek, Ben Alder, Ben Conand and Ben Nevis, the content of C18:4(n 2 3) was 2.9%
3.5%. m Measured by a standard Association of Official Agricultural Chemists (AOAC) method. n Extracted with chloroform:methanol.

102

Valorization of Fruit Processing By-products

amounts (5.2%
8.5%) of this C18:3n-6 fatty acid (Piskernik et al., 2018). The content of many other fatty acids quantified in berry pomace oils were determined to be lower than 1% with some exceptions; for instance, Piskernik et al. (2018) reported 6.1%, 7.73%, and 8.66% of myristic (C14:0) acid in black currant, red currant, and jostaberry oils, respectively. Dobson et al. (2012) determined ω-hydroxy fatty acids (mainly 16-hydroxy 16:0) and 2-hydroxy fatty acids (mainly 2-hydroxy 24:0) in black currant press residues; they were present at much greater levels in pomace containing seeds (2496, 2097, 958, and 46 mg/100 g oil, respectively) than in the separated seeds (553, 108, 161, and 1 mg/100 g oil, respectively). The yields and the composition of lipophilic constituents recovered from berry press cakes depend on which product part is used for extraction, that is, the whole pomace with the seeds or separated from pulp residues, skins, and seeds. Piskernik et al. (2018) separated the seeds from the pulp, ground them, and extracted using the Weibull and Stoldt method; oil yields were from 17.8% (black currant) to 22.4% (jostaberry) and the oil was composed mainly of PUFA (Table 5.2), which constituted 67.20% (gooseberry) to 73.34% (black currant). Crude fat content recovered from the whole black currant pomace was lower; for instance, extraction with a mixture of chloroform and methanol yielded 13.8% (Juskiewicz et al., 2017), while SFE-CO2 at optimal parameters recovered 14.71% of lipids (Oktay Basegmez et al., 2017). In another study, Dobson et al. (2012) extracted lipophilic components from the separated black currant seeds and the whole pomace with isohexane; the total amount and the content of unsaturated fatty acids was less in pomace than in seed alone (756 mg/g vs 910 mg/g oil), including γ-linolenic acid (86.5 mg/g vs 126.2 mg/g oil); however, the amount of longer chain n-20:0
n-30:0 fatty acids were higher in pomace (40.8 mg/g vs 4.37 mg/g oil). An effect of pretreating sea buckthorn pomace by ultrasonication or freezing for the yield of seed oil extracted with hexane was observed, although it was not remarkable: the yield was in the range of 13.1%
14.5%, while extraction efficiency was 90.5%
93.5% (Stoica-Guzun et al., 2018). Due to the high content of PUFA, berry seed oils are rather unstable in terms of oxidation; for instance, peroxide values (PVs) of commercially produced crude oils from cranberry, red raspberry, blackberry, and blueberry seeds were in the range of 31.97
42.75 mequiv. O2/kg, that is, highly exceeding 15 mequiv. O2/kg, the value set by Codex Standard 19-1981 for virgin oils and cold-pressed fats and oils (Van Hoed et al., 2011). Comparatively high PVs were also determined for commercially produced blueberry, red raspberry, marionberry, and boysenberry seed oils, namely 41.1, 46.5, 85.2, and 41.3 mequiv. O
OH/kg (Parry et al., 2005). Consequently, such oils should be stored at low temperature and protected against direct light. For instance, PV of raspberry oil freshly extracted by SFE-CO2 was only 0.62 mequiv. O2/kg and after 20, 50, and 210 days of storage in a refrigerator increased to 1.65, 2.14, and 7.41 mequiv. O2/kg (Kryˇzeviˇci¯ut˙e et al., 2016). Goldenberry waste powder oil’s iodine value (109.5 g/100 g of oil), acid value (2.36 mg KOH/g of oil), saponification value (183.8 mg KOH/g of oil), peroxide value (PV) (8.2 mequiv./kg of oil), and refractive index (1.4735) were comparable to those of soybean and sunflower oils (Mokhtar et al., 2018). In addition to total lipids, Dulf et al. (2012) determined the amounts of their fractions, namely polar lipids, triacylglycerols (TAGs), and steryl esters in bilberry, blueberry, cowberry, raspberry, and chokeberry pomace, while later the same team (Dulf et al., 2015, 2018) reported the results of the detailed analysis of total lipids, TAGs, polar lipids, mono- and diacylglycerols, and free fatty acids in black and dwarf elderberry and chokeberry pomace before and after SSF. Free fatty acids also are present in berry pomace lipophilic fractions: in blackberry and raspberry pomace their content in oleic acid equivalents, depending on pomace drying methods, was 1.18%
3.54% and 2.66%
8.89% (Radoˇcaj et al., 2014). It is known that the bioavailability of PUFA depends on the fatty acid position in the TAG molecule. However, the information on the TAG composition of berry pomace oils is rather scarce. Li et al. (2016a) determined LLLn, LLL (both 20.16%); LnLLn (24.39%) and LLLn (23.83%); LnLLn (17.96%) and LLLn (16.81) as the dominant TAGs in blackberry, black raspberry, and blueberry seed oils, respectively. Bakowska-Barczak et al. (2009) reported TAG composition in seed oil extracted from five black currant cultivars in HPLC-DAD mean peak area (%): αLnLγLn, LLαLn, LLγLn, and LLL were major TAGs with 9.6 2 10.6, 9.5 2 13.6, 9.5 2 11.9, and 10.1 2 14.0, respectively.

5.2.3

Phytochemical composition and bioactivities of pomace

5.2.3.1 Phenolic compounds Polyphenols are the main phytochemicals in berries and their pomaces. Therefore the majority of articles published to date have focused on the recovery, analysis, and evaluation of berry polyphenols. Different approaches have been used in the performed studies, and therefore the reported results are very variable and in most cases difficult to compare.

Berries Chapter | 5

103

Many studies applied spectrophotometric methods for determining TPCs, flavonoids, flavonols (TFI), total or monomeric anthocyanins (TMAs), and procyanidins (TPCd), and although the values obtained are related to the concentrations of particular groups of phytochemicals, the methods are not sufficiently specific to provide precise data on the target classes of phenolic compounds. For instance, flavonols and anthocyanins belong to flavonoids, while the values of TFI 1 TMA measured for wild and cultivated blackberry pomace were reported to be higher than the value of TFd (Jazi´c et al., 2019). Usually the contents of determined classes of compounds are expressed in gallic acid (GAEs), quercetin (QEs), rutin, cyannidin-3-glucoside (CyGEs), CEs, or other dominant compound equivalents; while their antioxidant and/or radical scavenging capacities are expressed in Trolox (TE) and ascorbic acid equivalents (AAE). Many studies also used more specific and precise methods for the identification and quantification of phenolic constituents, mainly different modifications of chromatography with various detection systems. Some authors expressed the results in fresh pomace weight (FW) or its dry weight or dry matter (DW or DM) [fresh weight (FW), DW], the others in g of extract dry mass or even in the concentration in the diluted with solvents extracts. The results reported in various studies on the content of the main anthocyanins are provided in Table 5.3. In many studies the researchers used different procedures for sample preparation (e.g., grinding procedures resulting in various particle sizes), as well as different extraction methods, solvents, and parameters; however, in some cases they did not measure the recovery of target phytochemicals and/or their classes from the initial pomace material. In fact both the information on the concentration of phytochemicals in the final extract and in the starting material are important for characterizing the product obtained and the raw material. In addition, it should be emphasized that some part of the phenolics may be strongly bound to the matrix of cell wall biopolymers and are not available for conventional extraction without effective pretreatments. Go¨kmen et al. (2009) for better characterization of wholesome foods and their ingredients developed the so-called QUENCHER procedure allowing the measurement of the phenolics and antioxidant capacity of the solid, nonextracted materials. In an ideal case the precise concentration of free and bound phenolics and other constituents should be determined in the initial material for successful development of effective valorization schemes converting berry pomaces into the most valuable ingredients. Many factors influence the concentration of phenolics in berry pomace, first of all, berry species but also their cultivars, ripening phase, growing conditions, etc. (Bobinait˙e et al., 2012, 2016a; Kraujalyt˙e et al., 2013, 2015). For instance, among phenolics determined in 19 berry species, the percentage of kaempferol, quercetin, myricetin, p-coumaric, caffeic, ferulic, p-hydroxybenzoic, and ellagic acids in the total amount of quantified phenolics were in the ranges of 0.0
9.4 (sea buckthorn
gooseberry); 1.7
87.3 (red raspberry
sea buckthorn); 0.0
21.2 (Arctic bramble/sea buckthorn
crowberry); 0.5
34.3 (blueberry
strawberry); 0.0
34.0 (strawberry/sea buckthorn
green currant); 0.0
68.3 (strawberry/gooseberry/white and green currant
blueberry); 0.0
53.7 (blueberry, sweet rowan
white currant); and 0.5
88.0 (sweet rowan
red raspberry), respectively (Ha¨kkinen et al., 1999). Consequently, the composition of berry pomaces also would be very variable. Pressing divides berry phytochemicals between the juice and the pomace in different proportions. Moreover, the composition of the main pomace structural elements, namely, skin, pulp, and seeds, is also different (Hilz et al., 2005, 2006). These factors are important for selecting and developing effective processing, extraction, fractionation, and purification methods, particularly in the case of mechanical separation of different fractions for further processing. In general, the distribution of phenolics depends on their composition in different berry species and cultivars as well as on juice extraction (pressing) peculiarities. It was reported that after pressing crowberries (Laaksonen et al., 2011) and black currants (Sandell et al., 2009) most of the sugars and acids are transferred to the juice, while the majority of phenolic compounds (anthocyanins) remain in the pomace. Holtung et al. (2012) reported that 57% of the phenolic compounds originally present in black currants were extracted into the raw juice, while the remaining 43% were left in the press residue. White et al. (2011) investigated the effects of grinding plus blanching, only grinding, and only blanching on the distribution of phenolics throughout the processing of cranberry juice and reported that flavonols and procyanidins were retained in the juice to a greater extent than anthocyanins; pressing resulted in the most significant losses in polyphenolics due to removal of the seeds and skins. The results also showed that cranberry polyphenolics are relatively stable during processing compared to other berries, although flavonol aglycones were formed during processing because of heat treatment (White et al., 2011). Polyphenolics are partially bound to the cell wall matrix of berry pomace and it may cause their incomplete extraction. White et al. (2010) applied optimized alkaline hydrolysis conditions to liberate procyanidins and depolymerize polymers from dried cranberry pomace and achieved a remarkable increase in low molecular weight (DP1
DP3) procyanidins (3.8
14.9 times compared to conventional extraction), particularly at higher temperature/short time combinations. Enzyme-aided pressing enabled the enhancement of polyphenol content in juice; however, a significant amount of these health-beneficial phytochemicals remained trapped in the pomace (Buchert et al., 2005; Koponen et al., 2008; Aaby et al., 2013). So´jka et al. (2013) reported the redistribution of

TABLE 5.3 Anthocyanins in berry pomace (standard deviations are omitted and the original values rounded up). Compound

BLa

D3gal

130.1

D3glc

4.4

D3ara

97.2

RRa

RCa

BBa

CHb

CHc

SCd

SCe

18.5
78.3

D3rut 60.5

Cy3glcrut

37.3

Cy3sam

2.7
5.6

0.6
1.4

ACRh

BIi

BIj

3.9
8.4

1.2
2.2

BLh

31.41

60.1

7.62

39.70

81

1.83

CRh

ACRh

LIh

6.47

42.8
295 1191
4422

60

18.5
78.3

280

0.7
1.6

0.2
1.0

1185
1657

2390

2.3
4.8

1.4
2.2

124.3 4.89

Cy3rut Cy3ara

BCg

26.27

Cy3sph

Cy3glc

BCf

14.2

Cy3gal

59.5

3.58

166.4

31.7

22.0

26.0

0.24
0.44

79.4

3.7
5.7

533

57.1

0.86

0.71

0.06

1.65

3.07

28.70

38.1

1.15

9.14

3.07

5.44

1.56

9.81

1.73

19.30

25.82

8.18

2.31

0.31

2.31

9.93

Pn3gal

3.04

2.73

20.2l

0.24

12.41

3.04

0.33

Pn3glc

0.36

20.44

42.8m

1.58

3.28

0.36

0.86

11.4

Pn3rut

92

k

26.50

Pt3ara

1112

49.18

1.73

Pn3ara

7.6
12.5

0.06

0
88.3

89.2

Pt3glc

8.55

5.54

8.95

51.1

6.50

M3glc

11.2

26.20

70

5.34

M3ara

355.8

6.39

14.6

19.61

ACR, American cranberries; ara, arabinoside; BB, blackberries; BC, black currant; BI, bilberries; BL, blueberries; CH, chokeberries; CR, cranberries; Cy, cyanidin; D, delphinidin; gal, galactoside; glc, glucoside; LI, lingonberries; M, malvidin; Pn, peonidin; Pt, petunidin; RC, red currant; RR, red raspberries; rut, rutinoside; SC, sour cherries; xyl, xyloside. a Jara-Palacios et al. (2019) (mg/100 g DM; in BL: M3gal 5 363.1; Pt3gal 5 106.8). b Mayer-Miebach et al. (2012) (g/kg wet basis; Cy3xyl 5 0.3
0.6). c Oszmia´nski and Wojdylo (2005) (mg/100 g DW; Cy3xyl 5 105). d Kołodziejczyka et al. (2013) (mg/100 g in three water extract fractions; Cy-dipentosyl-hexoside, 17.0
201). e Bajerska et al. (2016) (mg/kg DM, extracted with acidified 80% methanol). f Pap et al. (2013) (mg/g extract; M3rut 5 0.1
0.2; depending on extraction method and parameters—acidified water pH2 and MAE). g Klavins et al. (2017), in mg/g DW (extracted with ethanol 1 5% formic acid). h Klavins et al. (2018), in mg/g DW (UAE with ethanol 1 5% formic acid). i Bakowska-Barczak et al. (2009) (from 5 black currant cultivars in mg/100 g of defatted seed residue extracted with 50% acetone). j Aaby et al. (2013) (mg Cy3G/100 g pomace; Pt3gal 5 19.7). k 1 D3ara. l 1 Pn3ara. m 1 M3gal.

Berries Chapter | 5

105

individual phenolics in dried black chokeberry pomace, which was separated into six fractions on the basis of their granulation and by air separation. Thus the content of different classes of phenolics were in the following ranges (in mg/100 g DW): hydrocinnamic acids (chlorogenic 1 neochlorogenic), 89.7 2 231.6; total flavonols (sum of quercetin and four its glucosides), 57.0 2 126.8; anthocyanins (sum of four cyanidin glycosides), 616.2 2 1239.0; flavonols (sum of procyanidins and catechins), 7281 2 13,504; and total phenols, 8044 2 15,058. Van Hoed et al. (2011) determined 7.73 and 5.02 g/kg of p-coumaric acid in cold-pressed cranberry and blackberry oils, respectively; while other quantified phenolic acids (o-coumaric, homovanillic, vanillic, and protocatechuic acids) were present at remarkably smaller concentrations. Cranberry oil was also rich in the well-known natural antioxidant tyrosol (0.84 g/kg). Chokeberry pomace was richer in chlorogenic, caffeic, and ellagic acids, compared to black currant pomace (630.3 vs 38.5 mg/100 g), and anthocyanins (191 vs 114 mg/100 g) (Pieszka et al., 2015). TPC values measured for raspberry pomace extracts, depending on the extraction solvent (80% methanol or 80% acetone) and plant cultivar, were in the range of 93.88 2 163.8 GAE mg/g (for the whole berry, 43.64 2 83.13; pulp, 20.35 2 35.47 mg GAE/g); pomace extracts also contained the highest concentration of free ellagic acid (1.14 2 2.97 mg/g), followed by the whole berry (0.37 2 1.54 mg/g) and the pulp (0.27 2 1.09 mg/g) (Bobinait˙e et al., 2013). In the same study the measured concentration of ellagitannins (as ellagic acid) in acetone extracts of pomace after hydrolysis was in the range 36.18
62.42 mg/g. Oszmia´nski and Wojdylo (2005) quantified chokeberry phenolics by HPLC; their total amounts in fruit, pomace, and juice were 78.5, 105.8, and 37.3 mg/g DM, respectively. The content of procyanidins with different degree of polymerization (DP) (23 2 34), which were present in chokeberries at 5181.60 mg/100 g DW, after pressing was remarkably higher in pomace (8191.58 mg/100 g DW) than in juice (1578.79 mg/100 g DW); moreover pomace contained procyanidins with higher DP (Oszmia´nski and Wojdylo, 2005). The content of TPCd was about 45% higher in chokeberry pomace than in fresh berries before pressing and they were distributed as follows: 70% in the flesh, 25% in the skin, and 5% in the kernels (Mayer-Miebach et al., 2012). Skrede et al. (2000) reported that although the yield of press cake during the processing of highbush blueberry juice was only 10% (w/w), the content of total anthocyanins in pomace and juice was 184 and 33.6 mg/100 g, that is, only 32% of anthocyanins were recovered in juice. Recoveries of chlorogenic acid, flavonol glycosides, and procyanidins were 40.2%, 52.8%, and 38.0%, respectively (Skrede et al., 2000). Extraction with acetone demonstrated that black currant pomace contained approximately threefold higher TPC and TMA than fresh berries: 20.04 versus 6.25 mg GAE/g and 6.96 versus 2.36 mg Cy3GE/g, respectively (Holtung et al., 2012). The concentrations of anthocyanins in bilberries’ enzymatically treated mash, press residue, and raw juice were 347, 338, 550, and 268 mg Cy3GE/100 g, respectively (Aaby et al., 2013). TPCs of guelder-rose berries’ unwashed and washed pomace measured by QUENCHER method were 44.5, 50.4, and 42.1 mg GAE/g DW, respectively (Kraujalis et al., 2017). The content of different classes of polyphenolics may be highly variable both between wild and cultivated berries. Thus Jazi´c et al. (2019) reported the following amounts of different classes of phenolics in the pomace of two cultivated and two wild blackberry cultivars (in mg/g DW of fresh pomace): TPC 5 26.30 2 50.16 GAE; TFd 5 3.32 2 7.73 QE; TFI 5 2.55 2 6.63 QE; TMA 5 8.43 2 17.31 CyGE. The sum of phenolic acids and some flavonoids isolated from the pomace of the same blackberry cultivars and determined by HPLC was in the range of 7.79 2 18.59 mg/g DW. The content of polyphenols in sour cherry pomace extracted with aqueous ethanol was 645.3 mg GAE/100 g DW ˇ (Tumbas Saponjac et al., 2016). TPC and anthocyanin levels were remarkably higher in black currant press residue consisting of skins obtained after pressing fruits than in the commercial pomace, consisting of skins seeds and stems; however, acid hydrolysis liberated a much higher concentration of phenols from the pomace than from the press residue (Kapasakalidis et al., 2006). Kurek et al. (2018) quantified polyphenols in blueberry and blackberry pomace ethanol extracts (used for the preparation of novel antioxidant and pH indicator films) by HPLC. They reported 4.65, 2.28, and 4.13 mg/g of anthocyanins, flavonoid glycosides, and phenolic acids in blueberry and 13.90, 1.49, and 1.34 mg/g in blackberry pomace extracts. Delfinidin and malvidin derivatives, kaempferol glycoside, and chlorogenic acid were reported as the quantitatively major phenolics in blueberry; cyanidin derivative (10.24 mg/g) was dominant in blackberry pomace extract (Kurek et al., 2018). Kołodziejczyka et al. (2013) fractionated water extracts of industrial sour cherry pomaces with 20% and 60% ethanol in the Amberlite XAD-7HP column and obtained seven fractions, which were afterward selectively mixed to produce three preparations containing high amounts of phytocompounds (121
127 mg/g) determined by HPLC, including anthocyanins (12.69
67.73 mg/g), hydroxycinnamic acids (0
51.78 mg/g), and flavonols (0
45.22 mg/g), and demonstrated strong antioxidant capacity (192
1628 μmol TE/g). Jara-Palacios et al. (2019) identified and quantified 15 anthocyanins in the pomaces of blueberries, red raspberries, red currants, and blackberries: the highest amounts of anthocyanins were found in blueberries (11.88 mg/g); however, the highest TPC (34.47 mg/g) and antioxidant capacity (0.61 mmol TE/g) values were determined for red currant.

106

Valorization of Fruit Processing By-products

5.2.3.2 Lipophilic constituents TAGs are the major lipophilic components of berry pomace, and they are located mainly in the seeds (their composition is briefly discussed in Section 5.2.3). Besides oil, berry seeds accumulate various lipid-soluble microconstituents, which are extracted together with fat. They are important for berry oil stability; oxidative stability of cold-pressed blackberry, black raspberry, and blueberry seed oils was compromised after the removal of tocols (Li et al., 2016a). Natural tocols, as strong antioxidants and fat-soluble compounds possessing vitamin E activity, are of great interest for their recovery and applications. Tocopherols, which are the group of tocols with a saturated hydrocarbon chain attached to the chromane ring, have been the most widely studied in berry pomaces, and some of the reported results are listed in Table 5.4. However, tocotrienols were major tocols in bilberry, cranberry, arctic cranberry, crowberry, and lingonberry (all belong to Vaccinium spp.) seed oils: for instance, the concentration of the dominant γ-isomer was 0.3
1.9 mg/kg oil (Yang et al., 2011). Li et al. (2016a) determined 1.245 g of δ-tocotrienol per kg bilberry seed oil, Van Hoed et al. (2011) reported high amounts of γ-tocotrienol in cold-pressed cranberry (1105 mg/kg) and blackberry (305.6 mg/kg) oils. Dark color berries usually are rich in polar anthocyanin structure pigments, which are located mainly in the skin and pulp, while yellow-orange color berries may contain reasonable amounts of carotenoids, which are phytochemicals that are well known for their antioxidant properties and other health benefits. Anthocyanins are flavonoid phenolics and are poorly soluble in fats, while carotenoids are lipophilic compounds and therefore may be extracted with nonpolar solvents together with oils. Sterols are another group of lipophilic microconstituents, which have also been reported in berry pomaces; some of them are health-beneficial compounds, which are able to reduce low-density lipid (LDL) cholesterol levels in blood plasma. Only a few reports are available on the composition of sterols and carotenoids in berry pomace. Zieli´nska and Nowak (2017) reported detailed information on the composition and activities of sea buckthorn oil. Parry et al. (2005) quantified four carotenoids in cold-pressed blueberry, red raspberry, marionberry, and boysenberry oils; total contents were 19.0, 12.6, 23.4, and 30.0 μmol/kg, respectively, while zeaxanthin was the most abundant (7800
13,600 μg/kg) followed by β-carotene (82.2
2405 μg/kg), cryptoxanthin (717.6
1812.9 μg/kg), and lutein (53.3
97.7 μg/kg). Dulf et al. (2012) quantified 10 sterols in wild and cultivated Romanian bilberry, blueberry, cowberry, raspberry, and chokeberry pomaces; their total contents were 142.9, 101.7, 168.2, 150.2, and 148.2 mg/100 g lipids, respectively, whereas the major compound of this class, β-sitosterol constituted 55%
74% of the total quantified sterols. Dobson et al. (2012) quantified 10 phytosterols and six polycosanols (n-20:0 to n-28:0) in black currant oils extracted with isohexane from the separated seeds and the whole pomace; their total amount was 553 and 2496 mg/100 g, respectively, β-sitosterol being the major compound (460 and 2116 mg/100 g) followed by campesterol (44 and 184 mg/100 g). The amount of polycosanols was 108 and 2097 mg/100 g in the seed and pomace lipids, respectively. Bakowska-Barczak et al. (2009) quantified phytosterols in the oil extracted from five black currant cultivars: the total concentration was 57.9
69.9 g/kg, including the major constituent β-sitosterol, 38.8
50.5 g/kg. Other quantified sterols were campesterol (4.03
5.11 g/kg), stigmasterol (0.24
0.31 g/kg), Δ5-avenasterol (1.59
2.92 g/kg), Δ7-stigmasterol (1.43
1.82 g/kg), Δ7-avenasterol (0.98
1.35 g/kg), and citrostadienol (3.07
5.58 g/kg).

5.2.3.3 Antioxidant, antimicrobial, and other bioactivities of berry pomace Numerous studies evaluated the antioxidant potential of various berry pomaces, which is closely related to the content of phenolic compounds, most of which are strong radical scavengers. The majority of these studies applied simple in vitro chemical assays, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH ) and 2,20 -azino-bis(3-ethylbenzothiazoline-6sulfonic acid) (ABTS 1) scavenging, ferric reduction antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC). Again the difficulties in comparing previously reported data arise from different analysis methods and different ways of expressing antioxidant capacity values. Thus some authors measured the percentage of inhibition of radicals by the tested extract solutions (difficult to compare because the concentrations of applied solutions differ), while others reported the concentrations of antioxidants required to neutralize 50% of radicals present in the reaction (IC50 values). Antioxidant capacity values expressed in the equivalents of reference antioxidants, mostly TE or AAE, are more convenient for comparison. Moreover, it is important to know antioxidant capacity not only for the particular extract but also the amount of antioxidant units in the initial pomace material, which reflects its wholesome antioxidant potential. Unfortunately, such values have not been reported for many pomaces. Some reports on the in vitro effects of berry pomace extracts in various cell lines are also available, while the in vivo studies are rather scarce. Many studies reported higher antioxidant capacity values for the pomace than for the fresh berries or their pulps. Thus DPPH scavenging capacity values measured for raspberry pomace extracts, depending on the extraction solvent (80% methanol or 80% acetone) and plant cultivar, were in the range of 503 2 629 μM TE/g, while for the whole berries and their pulp they were lower, 300 2 460 and 141 2 240 μM TE/g, respectively (Bobinait˙e et al., 2013). G

G

G

Berries Chapter | 5

107

TABLE 5.4 The content of tocopherols (T) in various berry pomace products (some of the values are rounded up). Raw material

α-T

β-T

γ-T

δ-T

Sea buckthorn pomacea

278

86.1

195

70.6

Sea buckthorn pomacea*

40.6

12.6

28.5

10.3

1143

190

768

104

155

25.7

122

16.5

496

317

30.0

314

623

315

14.8

192

Guelder-rose berry pomace ***

561

229

12.2

162

Sea buckthorn seedc

900

800

100

900

100

35

5

520
1160

1310
2060

5530
11,410

a

Sea buckthorn seeds

a

Sea buckthorn seeds * b

Guelder-rose dried berries

b

Guelder-rose berry pomace ** b

Black currant seedc d

77

Black currant pomace e

Black currant seed c

3

0

600

300

c

700

3200

100

f

Raspberry seed

150.9

558.7

178.9

Raspberry pomaced

196

410

168

Red currant seed Raspberry seed

c

Strawberry seed

c

Cloudberry seed

51

0

200

1100

1500

c

Bilberry seed

Cranberry seedc

40

Cranberry seed oil

g

149

62.8

c

20.9

50

Arctic cranberry seed c

100

Crowberry seed

Snowball berry seedc

1100

400

600

52.4

187

46.3

39.0

1205

34.0

136

446

143

16.5

39.4

2.2

Blueberry

71.1

33.6

6.0

Marionberryf

28.4

328.3

50.0

20.8

688.6

232.0

c

Lingonberry seed

Blackberry seed oilh g

Blackberry seed oil (pressed) h

Black raspberry seed h

Blueberry seed f

Boysenberryf d

Sour cherry pomace i

Chokeberry a

29

9

7

1

1630

330

230

140

Kitryte˙ et al. (2017b) (mg/kg oil extracted at optimized SFE-CO2, *mg/kg pomace DW). Kraujalis et al. (2017) (mg/kg oil extracted at optimized SFE-CO2; **unwashed, ***washed). c Yang et al. (2011) (mg/kg oil extracted with SFE-CO2). d Go´rnas´ et al. (2016) (mg/kg pomace). e Bakowska-Barczak et al. (2009) (mg/kg oil, from five berry cultivars). f Parry et al. (2005) (mg/kg oil produced by cold pressing in Badger Oil Company). g Van Hoed et al. (2011) (mg/kg in pressed from seeds oil). h Li et al. (2016a) (mg/kg oil; also contained 1245 mg/kg δ-tocotrienol). i Grunovaite˙ et al. (2016) (mg/kg SFE-CO2 oil). b

108

Valorization of Fruit Processing By-products

The values of DPPH and ABTS 1 scavenging capacity of chokeberry fruit/pomace/juice were 279/302/127 and 439/780/314 μM TE/100 g DM, respectively (Oszmia´nski and Wojdylo, 2005). Antioxidant capacity values of wild and cultivated blackberry pomace extracts in DPPH , ABTS 1, and OH scavenging assays, expressed in IC50 were in the range of 106 2 206, 23.7 2 47.0, and 135 2 169 μg/mL, respectively; while antiproliferative activities of extracts against HeLa, MFC7, HT-29, and MRC-5 human tumor cell lines were 232 2 476, 232 2 307, 506 2 931, and 268 2 429 μg/mL (Jazi´c et al., 2019). Water extracts obtained from black currant (Holtung et al., 2012) and bilberry (Aaby et al., 2013) pomace at higher temperatures showed a stronger inhibition of Caco-2, HT-29, and HCT 116 cancer cell proliferation than the extracts produced at lower temperatures, possibly due to the decomposition of complex polyphenols, making them more accessible to the cells. Landbo and Meyer (2001) reported that selected black currant pomace extracts exerted a pronounced antioxidant activity against human LDL oxidation in vitro when tested at equimolar phenol concentrations of 7.5
10 μM. Yang et al. (2011) reported that the oils extracted by SFE-CO2 from 13 Northern berry seeds scavenged peroxyl radicals (0.3
2.3 mmol α-tocopherol equivalents per 100 g oil), while sea buckthorn seed and pulp oils protected purified DNA and rat liver homogenate from UV-induced oxidation, inhibited Cu21-induced LDL oxidation, and scavenged superoxide anions with IC50 5 2.0 and 1.1 μg/mg LDL and 2.3 and 0.6 mL/L, respectively (relevant values for Trolox were 1.6 μg/mg LDL and 8.2 mL/L). The total antioxidant activity of aqueous extract of chokeberry pomace was more than two times higher than that of black currant (179 vs 82 μg TE/g pomace), however DPPH scavenging capacities were similar for both berries (Pieszka et al., 2015). In vitro bioactivities of pomaces of Bianchi d’Offagna and Montmorency sour cherry cultivars, depending on genotype and drying method (oven or freeze
drying (FD)), were in the following ranges: α-glucosidase inhibitory activity, 67%
83%; IC50 of DPPH and ABTS 1 scavenging, 0.11
1.02 and 0.11
0.21 mg DW, respectively (Ciccoritti et al., 2018). Some berry pomace extracts were tested for their antimicrobial activity as well. Polyphenol extracts from industrial sour cherry pomaces reduced the growth of Salmonella and Escherichia coli O157:H7 at concentrations higher than 2500 μg/mL, and inhibited the growth of Listeria spp. (Kołodziejczyka et al., 2013). Stobnicka and Gniewosz (2018) produced swamp cranberry pomace extracts with 96% and 40% ethanol and water; they contained stilbenes and more organic acids and flavonols than fruit extracts and inhibited Gram-positive bacteria strains more strongly than Gramnegative, regardless of the used raw material. However the extract did not show antifungal activity, whereas hydroethanolic extracts were stronger antibacterial agents than ethanolic and aqueous extracts (Stobnicka and Gniewosz, 2018). Raspberry pomace extracts demonstrated higher inhibitory effects against Bacillus subtilis, Enterococcus faecalis and Staphylococcus aureus than the extracts isolated from the whole berries or their pulp (Bobinait˙e et al., 2013). Selected sour cherry pomace extracts reduced the growth of Salmonella and E. coli O157:H7 at concentrations higher than 2.5 mg/mL and inhibited Listeria spp. (Kołodziejczyka et al., 2013). The activities of isolates from the frozen cranberries and their pomace anthocyanins, water-soluble, and apolar phenolic compounds against vancomycin-resistant Enterococcus faecium, E. coli O157:H7, E. coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, and S. aureus were in a wide range both for different fractions and bacteria; seven fractions demonstrated maximal tolerated concentration , 2 μg phenol/mL, whereas the minimum inhibitory concentration of five fractions was ,10 μg phenol/mL (Caillet et al., 2012). G

G

G

G

G

G

G

5.3 5.3.1

G

Processing of berry pomace Postpressing preparation of berry pomace for processing

The content of water in the pomace is usually lower than in the fresh berries; however, it is sufficiently large to create good media for microbiological and enzymatic processes. For instance, black currant pomace consisting of peels, seeds, branches, and some remaining flesh had 41.4% DM, while DM in the berries was twofold lower, 21.9% (Holtung et al., 2012). The content of DM (w/w) in chokeberries and their pomaces was 17.9%
26% and 44.6% 2 50%, respectively (Mayer-Miebach et al., 2012). Water content in blackberry and raspberry pomaces was 48.39% and 50.05%, while after drying, depending on the methods applied, it reduced to 6.08%
6.66% and 6.06%
8.55%, respectively (Radoˇcaj et al., 2014). Consequently, fresh pomace cannot be stored at ambient temperature for a long time and should be dried and/or frozen until further handling. The selection of such pretreatments depends on various factors, including processing and application aspects. For instance, in the case of using the pomace for fermentation, most likely freezing would be the preferable preservation method; after thawing its moisture may be adjusted to the optimal level for the fermentation without drying. This process also might be convenient in the case of extraction of pomace with water or the mixtures of protic solvents, for example, ethanol and water. In this case the batch of pomace may be thawed and immediately extracted with the selected solvent. However, for many applications and/or processing purposes the pomace should be

Berries Chapter | 5

109

dried, usually until the moisture content reaches less than 10%, thus reducing water activity to the levels that are unfavorable for microbiological and fermentation processes. To avoid possible negative effects of heat on sensitive bioactive phytochemicals (e.g., their thermal degradation) FD has been frequently used; however, this method in most cases is too expensive for commercial processing and therefore most often was applied for analytical and other purposes in laboratory-scale studies. Cheaper and higher output conventional methods of drying with hot air have been widely used for pomace both for analytical and process development purposes. Drying may induce oxidation of PUFA-rich berry seed oils. For instance, the following PV (in mmol/kg) were determined for oils extracted from the pomace of blackberries and raspberries: from fresh fruits, 3.73 and 4.82; from frozen and dried at 22 C/72 h, 8.84 and 13.97; from frozen and dried in two steps: (1) at 63 C/20 h and (2) at 103 C/20 h (blackberries) and (1) 63 C/6 h and (2) at 103 C/4 h (raspberries), 11.4 and 13.83, respectively (Radoˇcaj et al., 2014). In recent years new innovative thermal and nonthermal processing technologies for berry and berry products have been developed, including microwave, ohmic heating, high-pressure processing, irradiation, dense-phase carbon dioxide, ultrasonic processing, pulsed electric field, ozone, membrane processing technologies, cold plasma, and hydrothermodynamic cavitation (Li et al., 2017). Some advanced drying methods have also been applied to berry pomace. Bilberry pomace dried by FD generated a powder with smaller particles and lower bulk density than either the microwave-assisted hot-air (MWHA)-dried or hot-air-dried powders (Eliasson et al., 2017). Kerbstadt et al. (2015) applied for bilberry pomace infrared (IR) drying, infrared impingement (IRI) drying, and MWHA drying at 40 C and 70 C to moisture contents of 6% and 20% (w/w) and compared with FD; the total anthocyanin content of extracts obtained by SFE-CO2 with 50% cosolvent ethanol, depending on the applied drying technique, temperature, and moisture, varied in the range 13.67
43.66 mg/g DW. Zielinska and Michalska (2018) compared drying kinetics of hot-air convective (HACD), microwave vacuum (MWVD), and combined (HACD 1 MWVD) drying methods and their effects on blueberry pomace bioactive compounds and color; MWVD shortened drying time even by 91%. Drying caused degradation of TPC (39%
76%), TMA (21%
77%), and antioxidant capacity values (24%
76%); however, MWVD resulted in the smallest, while HACD at 60 C had the greatest loss of bioactives and antioxidant capacity. Ciccoritti et al. (2018) evaluated the influence of genotype, drying method, and their interaction on the extractability of phenolics and anthocyanins from sour cherry pomace: Bianchi d’Offagna cultivar pomace had remarkably higher content of phenolics than Montmorency cultivar, including TPC content (45 vs 19 mg GAE/g DW), TMA and HPLC measured anthocyanins (4.3 vs 0.22 mg CyGE/g, and 5.82 vs 0.078 mg CyGE/g, respectively) and flanav-3-ols (23.1 vs 14.2 mg CE/g DW). Drying method also significantly influenced TMA, TFI, TPC, and vitamin C of the analyzed pomaces. Particle size is another important parameter in the preparation of berry pomace for further processing, particularly extraction. For instance, a decrease in black currant pomace particle sizes from 0.5
1 to ,0.125 mm increased the yields of phenols 1.6
5 times, while seedless pomace gave significantly higher yields of phenols than pomace with seeds (Landbo and Meyer, 2001).

5.3.2

Extraction of various constituents from berry pomace

Extraction is the main method for the recovery of target compounds from berry pomace. In general, all extraction methods, which have been applied to berry pomace, may be grouped into conventional (traditional) and more modern processes. Different types of conventional solid
liquid extraction have been widely used for pomace; however, in many cases for analytical purposes, for example, to produce crude extracts or fractions for further determination of chemical composition and properties (see Section 5.2) Soxhlet extraction (SE) and maceration with shaking were among the most frequently used techniques applied for the isolation of the components from the pomace by using different procedures, solvents, and extraction/fractionation parameters. Some of the data obtained in laboratory-scale extractions might be also applied for developing technological processes for the valorization of the pomace, for example, by upscaling the procedures to a pilot plant and even industrial scale processes. SFE-CO2, pressurized liquid extraction (PLE), high pressure (HP), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), enzyme-assisted extraction (EAE), microwave hydrodiffusion and gravity (MHDG), and bead-milling (BM) are other methods of extraction tested for berry pomace. It should be noted that nowadays there is a preference for using green chemistry-based extraction technologies instead of conventional methods, which very often are performed by using large amounts of hazardous organic solvents. Green chemistry principles, among others, include the use of innocuous solvents (5th principle), and the selection in the chemical processes of such substances that minimize the potential for chemical accidents, including releases, explosions, and fires (12th principle) (Erythropel et al., 2018). The use of green chemistry principles is an important trend in developing extraction/fractionation methods for agrofood materials, particularly for recovering the substances intended

110

Valorization of Fruit Processing By-products

for human applications such as foods, nutraceuticals, and cosmetics. Therefore food grade solvents such as water, ethanol, liquid, and supercritical CO2 would be regarded as preferable for the recovery of berry pomace constituents as well. Another trend in green chemistry-based extraction, as an alternative to the use of hazardous organic solvents, includes tailor-made deep eutectic solvents (Jablonsky´ et al., 2018) and ionic liquids (Passos et al., 2014), which have been increasingly applied in the extraction of value-added compounds from biomass in the past few years. The results obtained by different extraction techniques will be shortly discussed in this section using the above listed abbreviations for indicating the methods.

5.3.2.1 Conventional solid
liquid extraction Berry pomace is a complex heterogeneous biomaterial containing a large number of components belonging to various chemical classes of natural compounds and distributed in different berry anatomical parts, namely seeds, skins, and pulp. Therefore numerous factors should be considered when selecting the most suitable extraction methods for each individual berry pomace. In general, “ideal” methods for analytical purposes should provide 100% recovery of the unchanged target constituent(s), whereas for industrial pomace valorization such aspects as technological and economic feasibility of process upscaling, solvent properties (e.g., toxicity, flammability, and environmental impact), and reduction of waste should be considered. In general, conventional extraction methods are simple, however for the exhaustive recovery of target compounds, large amounts of solvents are required, which after the process should be evaporated; therefore extraction time is usually long. Fig. 5.1 illustrates the recovery of soluble substances and product characteristics during a three-step conventional extraction process of raspberry pomace with ethanol and water (Bobinait˙e et al., 2010, 2013). It may be observed that, although the first extraction step recovered the largest portions of total soluble constituents (extract yield) and different groups of compounds, the second and the third steps still extracted some residual amounts. A few years later Bobinait˙e et al. (2016b) extracted raspberry pomace from different plant cultivars with 80% methanol and 80% acetone at room temperature for 60 min under shaking in two steps; the yields of the extracts were almost similar (7.67% and 7.55%), also the differences in the measured characteristics, namely TPC, TMA, ellagic acid, ellagitannins, and DPPH scavenging capacity, were not considerable. For instance, DPPH scavenging capacities of methanol and acetone extracts were in the ranges 489
595 and 548
628 μmol TE/g, respectively (Bobinait˙e et al., 2016b). Consequently, when upscaling such extraction methods for commercial applications, a decision should be made regarding safety and technological/economic feasibility, that is, when extraction should be interrupted and what percentage of targeted compounds should be left in the final residue. So far as several factors may influence extract yield and recovery of target compounds, some studies have optimized the process parameters, for example, particle size of ground material, solvent/solid ratio, extraction time, temperature and others, using response surface methodology (RSM), most often based on the Box
Behnken design. It should also be noted that due to a large variability in extraction methods and parameters, which have been used in the reviewed literature sources, the reported results sometimes are rather difficult to compare, even for pomace of the same berry species. Lapornik et al. (2005) reported that ethanol and methanol extracts of red and black currant pomace contained twofold more anthocyanins and polyphenols than water extracts; in water extracts the yields of polyphenols decreased, while in methanol and ethanol extracts their content increased with the time of extraction. Ethanol extracted nearly all the phenolic compounds from the crowberry pomace leaving only fibers and seeds (Laaksonen et al., 2011). Wajs-Bonikowska et al. (2017) compared SE of blackberry pomace with hexane and ethanol and SFE-CO2: SE with ethanol gave the highest yield (14.2%) and the extract contained the highest TPC (9443 mg GAE/100 g) and exhibited the highest antioxidant capacity. Flores et al. (2013) compared acetone, ethanol, and methanol for extraction of whole blueberries and their pomace: ethanolic crude Amberlite extracts demonstrated the highest TMA (160 ppm), TPC (382 ppm GAE), FRAP (3.4 mM Fe21), and α-amylase inhibitory activity (36.8%), while the rehydrated powder from the acetone extract showed the greatest FRAP (5.19 mM Fe21) and TPC (422.7 ppm GAE) values. Yılmaz et al. (2015) applied RSM for the extraction of sour cherry pomace and reported that optimal conditions were 51% ethanol, 75 C temperature, and 12 mL/g solvent to solid ratio; at these conditions TPC and TMA values, cyanidin-3-glucosyl rutinoside, neochlorogenic acid, and catechin contents were 14.23, 0.41, 0.19, 0.22, and 0.22 mg/g, respectively. The yields of SFE-CO2 and hexane extracts from blackberry pomace were almost equal, 11.4% and 11.8%, respectively; while that obtained by extraction with ethanol as a solvent was the highest (14.2%) (Wajs-Bonikowska et al., 2017). Polar solvents recovered remarkably higher amounts of polyphenolic antioxidants: the ethanol extract of blackberry pomace had 148 and 50 times higher TPC than the hexane and CO2 extract, respectively, and was a remarkably stronger ABTS 1 and DPPH scavenger, 1011 and 1224 μmol TE/g versus 12.19 and 14.22 μmol TE/g (CO2 extract), respectively (Wajs-Bonikowska et al., 2017). Extraction temperature is an important extraction factor; usually the process rate and G

G

G

G

FIGURE 5.1 Characteristics of three-step extraction of raspberry pomace.

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Valorization of Fruit Processing By-products

extract yields increase with the increasing temperature. For instance, Aaby et al. (2013) evaluated the effect of water temperature (22 C
100 C) and duration (4
45 min) on the extraction yield of phenolic compounds from bilberry pomace: the highest recovery of TPC and TMA, 37% and 67%
68%, respectively, was obtained at 80 C/15 min and 100 C/4 min. The recovery of anthocyanins increased from 70 mg Cy3GE/g pomace at 22 C/30 min to 332 mg Cy3GE/g pomace at 80 C/30 min, and that of flavonols from 62 to 173 mg/100 g; however, a further increase of temperature to 100 C/30 min resulted in a decreased recovery of anthocyanins to 234 mg Cy3GE/g (Aaby et al., 2013). Most recently Wathon et al. (2019) developed a novel and industrially scalable integrated extraction
adsorption method using acidified 60 C water for extraction and Amberlite XAD-7 for adsorption for producing large quantities of anthocyanin concentrates from chokeberry skins, consisting of cyanidin-3-O-galactoside (45.7%), cyanidin-3-O-arabinoside (16%), cyanidin-3-O-glucoside (3.6%), cyanidin-3-O-xyloside (2.7%), and the cyanidin aglycone (32%).

5.3.2.2 Ultrasound- and microwave-assisted extraction UAE and MAE have been widely used for increasing extraction rate and extract yields from different plant origin materials. Chemat et al. (2017) comprehensively reviewed the merits of UAE by its benefits, including process intensification among others. Klavins et al. (2017) compared UAE, MAE, and SE for the recovery of polyphenols from American cranberries; UAE showed the highest potential of all the studied methods, whereas acidified aqueous ethanol and methanol (with trifluoroacetic acid for anthocyanins and HCl for polyphenols) were recognized as the best solvents: cyanidin-3-O-arabinoside, peonidin-3-O-galactoside, peonidin-3-O-glucoside, and peonidin-3-O-arabinoside were found to be the major anthocyanins in cranberry pomace extracts. Later Klavins et al. (2018) applied optimized by RSM UAE parameters for Vaccinium berry press residues: the total anthocyanin concentration in the extracts measured by ultra performance liquid chromatography (UPLC) (in mg/g extract) was 284.95 for bilberries, 84.12 for highbush blueberries, 43.53 for cranberries, 7.08 for American cranberries and 27.58 for lingonberries (Table 5.3). He et al. (2016) optimized UAE at 400 W of phenolics from blueberry (Vaccinium virgatum) wine pomace using Box
Behnken design: the recovery of TMA did not remarkably depend on temperature (50 C
70 C), liquid
solid ratio (15
25 mg/L) and sonication time (15
35 min) and was in the range of 3.65
4.11 mg Cy3GE/g; while TPC values were in a wider range, 7.19
16.01 mg GAE/g. Conventional extraction with acidified 70% ethanol at 61 C/35 min gave only 1.72 mg Cy3GE/g of TMA and 5.08 mg GAE TPC. The MAE gave significantly better results than hot water in the extraction of pectin from press residues of red (68.3% vs 50.1% to total water-soluble pectin content) and black currant (64.1% vs 41.4%), raspberry (83.7% vs 73.8%), and elderberry (59.4% vs 41.3%); the gels of pectin from berry pomaces were somewhat weaker than the gel of commercial citrus pectin, but stronger than that of commercially available apple pectin (Be´lafi-Bako´ et al., 2012). MAE using acidic solvents was optimized for anthocyanin extraction from black currant pomace and maximum yields were achieved at pH 2 with an extraction time of 10 min with a microwave power of 700 W; compared to conventional extraction MAE was many times faster, used twofold less solvents and gave a 20% higher final anthocyanin concentration (Pap et al., 2013). Li et al. (2016b) optimized the extraction of flavonols and anthocyanins from black currant pomace by using homogenate
MAE. Under optimum conditions (60% ethanol, homogenate time, 3 min; liquid
solid ratio, 28.3 mL/g; 0.3% tert-butylhydroquinone; pH 2.5; microwave irradiation power and time 551 W and 16.4 min) the yields of flavonols and anthocyanins were 2323.3 and 473.7 μg/g, respectively. Simsek et al. (2012) reported that TPC and antiradical efficiency (AE) of sour cherry pomace extracted by MAE at optimal conditions (700 W, ethanol
water, 12 min, 20 mL solvent/g solid) was only slightly higher compared to conventional extraction during 6 h, 14.14 versus 13.78 mg GAE/g sample and 28.32 versus 24.74 mg DPPH mg GAE/g sample; however extraction time was reduced many times.

5.3.2.3 Supercritical fluid, pressurized liquid, and high-pressure extraction Conventional extractions are usually performed at atmospheric pressure with liquid solvents, while gases are not suitable for extraction due to a very low density; therefore they should be liquefied by compressing. Moreover, increasing pressure and temperature above a critical point converts the gas into a supercritical fluid, which can be used for extraction; its solubilization power highly depends on pressure and temperature. Nowadays this principle is widely used for the extraction of natural raw materials mainly using CO2, which is recognized as a benign solvent and therefore particularly suitable for the production of food grade extracts. High-pressure extraction (HPE), including the use of supercritical CO2, which has gained popularity in the processing of biomass, is emphasized as a technology of increasing importance due to the numerous CO2 advantages over traditional organic solvents: it is renewable, nontoxic, and easily recyclable (Arshadi et al., 2016). However, CO2 is a nonpolar solvent and may effectively dissolve only lipophilic substances. Cosolvents, mainly ethanol, are used for increasing the system polarity and the recovery of higher polarity

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constituents. The efficiency of SFE-CO2 in the recovery of lipids in most cases is evaluated by comparing extract yields with standard SE or other methods using nonpolar organic solvents, for example, hexane, petrol ether, or others. SFECO2 has been applied for extracting various berry pomaces and particularly berry seeds. SFE-CO2 effectiveness highly depends on various process parameters, mainly pressure, temperature, and time; therefore many studies applied RSM for determining the optimal extraction conditions for berry pomace. For instance, the yield of raspberry pomace oil at 10 MPa was only up to 2.59%, while at optimized parameters (45 MPa, 60 C, and 120 min) it reached 14.6% (Kryˇzeviˇci¯ut˙e et al., 2016). The yields of bilberry seed oils depending on pressure (20
50 MPa) and temperature (40 C 2 60 C) were from 7.6% (20 MPa, 60 C) to 22.2% (50 MPa, 60 C) (Gustinelli et al., 2018); however, the differences in the main fatty acid composition between oils extracted at various parameters were not significant. When a narrower interval (30 2 55 MPa) of HP was used for RSM optimization, extract yield varied less significantly, for example, 12.88% 2 14.76% in the 30 C 2 60 C temperature and 60 2 150 min extraction time range (Oktay Basegmez et al., 2017). Consequently for upscaling the process comparatively low temperatures and short extraction time may be selected to obtain good recoveries of lipophilic substances from berry pomaces. Manninen et al. (1997) extracted dried cloudberry pomace by large-scale SFE-CO2; oil yield at optimal conditions was 15% lower than in a laboratory SE with diethyl ether. SE of the original pomace yielded 93.0% neutral lipids, 3.8% glycolipids, and 3.2% phospholipids, whereas the corresponding proportions of the fractions in the oil of the residue after SFE-CO2 were 70.3%, 23.5%, and 6.2%, respectively; it means that approximately 11% of the total neutral lipids remained unextracted (Manninen et al., 1997). The yields of SFE-CO2 and hexane extracts from blackberry pomace were almost equal, 11.4% and 11.8%, respectively (Wo´zniak et al., 2016); however, in the case of black currant pomace SFE-CO2 at optimized parameters recovered 14.6% of lipids and it was 28% higher than in SE (Oktay Basegmez et al., 2017). SFE-CO2 and hexane extracts were characterized by the highest content of phytosterols (1445 and 1583 mg/100 g extract, respectively), among which β-sitosterol was the main one (1026
1383 mg/100 g), while the concentration of tocopherols, with the predominant γ-isomer, was the highest in hexane and ethanol extracts, 2364 and 2334 mg/100 g, respectively (Wajs-Bonikowska et al., 2017). Yang et al. (2011) determined fatty acid and tocol composition as well as antioxidative properties of seed oils extracted by SFE-CO2 (35 MPa, 50 C, CO2 flow rate 0.4 L/min, 120 min) from 13 Northern berry species; however, extract yields were not reported. After ethanol extraction of crowberry pomace, only fibers and seeds were left, and a pilot-scale SFE-CO2 recovered less than 1% of compounds from this residue (Laaksonen et al., 2011). The SFE-CO2 oil at 20 MPa and 60 C from bilberry seed had the best recovery of vitamin E and the lowest EC50 and PV values (Gustinelli et al., 2018). Some studies tried to use SFE-CO2 for the recovery of polyphenols; however, unpolar CO2 is not effective for the solubilization of higher polarity and hydrophilic compounds. Therefore the use of polar cosolvents is required to obtain higher yield of phenolic compounds from berry pomace. For SFE-CO2 of berry pomaces, polar solvents were simply mixed with plant materials before extractions or supplied by extra pump during the whole extraction time. For instance, Wo´zniak et al. (2016) added an increasing amount of ethanol (20%
80% of pomace mass) to sour cherry pomace before SFE-CO2: the best results for the recovery of anthocyanins (58%) and TPC (48%) were obtained at 10 MPa, 35 C, and 80% ethanol. Eliasson et al. (2017) extracted hot-air, microwave, and freeze-dried bilberry pomace at 35 MPa and 50 C using equal flows (3 g/min) of 80% ethanol and CO2: the yields of anthocyanins, depending on drying method and particle size (,0.71 mm and .0.71 mm) were 50
85 g/kg (in conventional methanol extraction 60
85 g/kg). However, this study applied an unusually high proportion of cosolvent (50%) for SFE-CO2, which is not convenient in terms of obtaining solvent-free extracts. Kerbstadt et al. (2015) also used 50% acidified with 1% HCl ethanol for bilberry pomace dried by IR drying, IRI drying, MWHA drying, and FD (final moisture content 5 6% or 20% at 40 C or 70 C): total anthocyanin content varied from 13.67 to 43.66 mg/g DW; while the highest recovery was obtained from IRI dried at 70 C to 20% moisture pomace. Grunovait˙e et al. (2016) demonstrated that increasing the amount of cosolvent ethanol from 0% to 10% enabled an increase in chokeberry pomace SFE-CO2 yield from 2.95% to 7.08%; the TPC value in the extract also increased from 23.9 to 34.3 mg GAE/g; however, it still was 15 times lower than in the ethanol extract, showing the low effectiveness of SFE-CO2 for polyphenols. SFE-CO2 was used for obtaining extracts with increased concentrations of selected constituents. Manninen et al. (1997) applied countercurrent extraction of cloudberry oil in 3 m 46 mm diameter column at 23 MPa and 40 C; the content of α 1 β carotenes in the raffinates decreased approximately with a factor of 8, while the enrichment factor for tocopherols was the opposite, 1.7 on average. Tocopherol-rich extracts may be obtained by changing CO2 extraction parameters; for instance, bilberry seed oil extracted at 20 MPa and 60 C contained 129.2 mg/100 g oil tocopherols, approximately twofold more than in the oils obtained at 35 and 50 MPa; however, due to a low yield of oil at 20 MPa the total amount of recovered tocopherols from 100 g dry seeds was lower, 9.8 versus 12.9
14.5 mg/100 g dry seeds (Gustinelli et al., 2018).

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High hydrostatic pressure is mainly used for preservation purposes and only a few studies have tested it for extraction. For instance, Adil et al. (2008) reported that at the optimal HPE conditions applied to sour cherry pomace (176
193 MPa, 60 C, 0.06
0.07 g solid/mL solvent, 25 min extraction time), TPC and AE values were 3.80 mg GAE/g and 22 mg DPPH/g, respectively; while in the case of SFE at optimal parameters (54.8
59 MPa, 50.6 C
54.48 C, 20 wt.% ethanol, 40 min) these values were only 0.60 mg GAE/g and 2.30 mg DPPH/g, respectively.

5.3.2.4 Extraction with pressurized liquids and at high pressure In principle, extraction with PLE is similar to the conventional solid
liquid extraction, however, the main advantage of increasing process pressure is related to the possibility of keeping low-temperature boiling solvents, both water and organic ones, in a liquid state at higher temperatures. In addition, the dielectric constant of solvents decreases when increasing their pressure and therefore the solubility of different analytes in the solid matrix present changes. For instance, the dielectric constant of water at HP and temperature decreases toward the dielectric constant of such powerful protic organic solvents as ethanol and methanol. Sometimes pressurized extraction is called “subcritical extraction.” PLE remarkably reduces extraction time and, in many cases, increases extract yields. Currently PLE is used mostly at laboratory scale in commercial instruments such as Dionex accelerated solvent extractors (ASE 200, ASE 300) operating at the constant 10.3 MPa pressure. HPE is performed by placing the extraction mixture (solvent and solid material) in a high-pressure apparatus. Both methods intensify the mass transfer processes and extraction rate. However, the industrial implementation of PLE and HPE is restricted mainly by high industrial equipment costs or its absence in the market as well as insufficient technological and economic evidence substantiating investments required for process commercialization. Very few publications are available on the use of PLE for valorizing pomace, most deal with grape (Yammine et al., 2018) and apple (Perussello et al., 2017) pomaces. In the case of other berries PLE was demonstrated as a useful downstream green process for the valorization of black chokeberry pomace residues remaining after SFE-CO2 (Brazdauskas et al., 2016). PLE proceeds vary fast, for instance, the yields of extracts from raspberry pomace with hexane and methanol in the range of 5
20 min time and 50 C
110 C were 13.6%
14.8% and 21.6%
25.1%, respectively (Kryˇzeviˇci¯ut˙e et al., 2016). However, TPC and ABTS 1 scavenging values of the extracts obtained at the same parameters were in a wider range (in μmol TE/g): 5.55
11.04 (hexane) and 26.31
38.95 mg GAE/g (methanol); 48.5
122.7 (hexane) and 308
561 (methanol), respectively. PLE and EAE with acetone, ethanol, or water was able to obtain an additional 12.3%
39.9% of extracts from SFE-CO2 residues (Oktay Basegmez et al., 2017). Grunovait˙e et al. (2016) tested different variations of solvents (hexane, methanol, water, acetone/water, and methanol/water mixtures) and temperatures (40 C
130 C) for PLE of chokeberry pomace and its residues after SFE-CO2: extract yields and TPC values were in the ranges of 4.26%
48.13% (in SE 5.3%
25.92%) and 26.25
490.4 mg GAE/g extract (in SE 21.62
512.4 mg GAE/g), respectively. The highest recoveries of the main flavonoids, hyperoside and rutin, were achieved by PLE of the whole pomace with methanol/water at 130 C, and that of chlorogenic acid by PLE of SFE-CO2 residue with acetone at 70 C (Grunovait˙e et al., 2016). PLE of chokeberry pomace residue after SFE-CO2 using green solvent ethanol gave 28.6% yield (Kitryt˙e et al., 2017a,b). Brazdauskas et al. (2016) optimized PLE temperature (50 C
170 C), ethanol (0%
100%) and formic acid (0%
2%) concentration for PLE of chokeberry pomace residue after SFE-CO2: the yield was from 20.82% to 75.66% (170 C, 50% ethanol, and 2% formic acid), TPC values were in the range of 86.7
258.3 mg GAE/g extract. In general, the studies on PLE demonstrated the importance of process optimization for obtaining high yields and extracts with a high content of phenolics and antioxidant capacity. Da Fonseca Machado et al. (2017) compared UAE, PLE, and UAE 1 PLE for the extraction of polyphenols (anthocyanins). Depending on the method and solvent (acidified water pH 2.0; 50% and 70% ethanol) global extract yields from blackberry, blueberry, and grumichama pomace were 5.70%
80.74%, 6.96%
89.89%, and 6.69%
85.06% (SE with ethanol: 12.03%, 15.30%, and 11.51%), respectively; TPC 20.8
8.84, 2.47
8.54, and 2.26
14.78 mg GAE/g (SE: 7.84, 6.83, 9.44) dry residue (DR); TMA 1.02
2.38, 1.07
2.15, 0.10
0.87 mg Cy3GE/g DR (SE: 2.82, 2.58, 0.97). In general, extraction efficiency for TPC and antioxidant capacity in decreasing order was UAE 1 PLE . PLE  Soxhlet . UAE, and for TMA Soxhlet  UAE . UAE 1 PLE . PLE using hydroethanolic mixtures as solvents (Da Fonseca Machado et al., 2017). G

5.3.2.5 Enzyme-assisted processing The application of enzymes for improving juice extraction is briefly discussed above. Enzymatic treatment may also be applied for the recovery of berry pomace fractions that are insoluble in various solvents, for instance, from the residues remaining after extraction with different polarity solvents. The treatment with enzymes may also be applied to the

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initial materials before extraction in order to facilitate the release of cell wall
bound phytochemicals or to increase the amount of extractable saccharides. Therefore the interest in EAE applications for the recovery of valuable berry constituents is increasing. Commercially available pectinolytic and cellulolytic enzymes allow the selective extraction of nutrients (e.g., pectin, sugars, proteins), essential oils, and phenolic phytochemicals, facilitating cell wall breakdown and/or enzymatic cleavage of glycosylated conjugates thereof (Acosta-Estrada et al., 2014). EAE depends on many factors such substrate type, selected responses, enzyme concentration, incubation time, temperature, and others; therefore process optimization is critical for effective enzyme treatment as was shown by Kitryt˙e et al. (2017a,b) who optimized commercial enzyme preparation Viscozyme L for EAE of chokeberry pomace. Promising results in terms of increased extraction yields, improved extract composition and bioactive constituent concentration have been demonstrated for black currant (Landbo and Meyer, 2001; Kapasakalidis et al., 2009; Oktay Basegmez et al., 2017), elderberry (Dulf et al., 2015), chokeberry (Kitryt˙e et al., 2017a,b; Dulf et al., 2018), and sea buckthorn (Kitryt˙e et al., 2017a,b) pomaces. Landbo and Meyer (2001) reported that commercial pectinolytic (Grindamyl pectinase, Macer8 FJ, Macer8 R, and Pectinex BE) and proteolytic (Novozym 89 protease) enzyme preparations significantly increased plant cell wall breakdown and the amount of extracted phenols (except for Grindamyl pectinase) in processing of black currant pomace; however the effects on anthocyanin extraction were different: Macer8 FJ and Macer8 R decreased; Pectinex BE and Novozym 89 protease had no effect. Cellulase also increased plant cell wall polysaccharide degradation of black currant pomace and enhanced the extractability of phenolic compounds with methanol; for instance, at 50 C anthocyanin yields increased by 44% after 3 h and by 60% after 1.5 h for the lower and higher enzyme/substrate ratio, respectively (Kapasakalidis et al., 2009). EAE of raspberry pomace with an hydroethanolic mixture (75:25, v/v) for 18 h at 50 C increased TPC up to 35% and antioxidant capacity by approximately 50%, 15%, and 30% in DPPH, ABTS, and FRAP assays, respectively (Laroze et al., 2010). According to Dulf et al. (2015) SSF of black and dwarf elderberry pomace resulted in the increase of the extractable phenolics by 11.11% and 18.82%, respectively; the levels of antioxidant capacity of pomace methanolic extracts also was significantly enhanced after SSF. However, a longer fermentation period resulted in a loss of anthocyanins, for example, before fermentation the content of cyanidin-3-sambubioside-glucoside, cyanidin-3-sambubioside, cyanidin-3,5-diglucoside, and cyanidin-3-glucoside in Sambucus nigra was 44.94, 4.46, 18.70, and 7.90 mg/100 g DW (black elderberry) and 28.90, 3.56, 13.71, and 2.59 mg/100 g DW (dwarf elderberry), respectively; whereas after 7 days of fermentation these values were 37.02, 4.16, 11.68, 1.80 mg/100 g DW and 27.52, 2.19, 13.19, 1.28 mg/100 g DW, respectively. The content of quantified by HPLC-MS chlorogenic acid, rutin, and isoquercetin after 7 days of fermentation was 0.82
4.49, 30.07
45.50, and 13.10
25.45 mg/100 g DW in black and 18.16
25.04, 5.82
13.01, 7.34
10.69 mg/100 g DW in dwarf elderberry, respectively (Dulf et al., 2015). More recently, positive effects of SSF with the same microorganisms on the amounts of extractable phenolics, total flavonoids, and lipids were shown for chokeberry pomace (Dulf et al., 2018). Kitryt˙e et al. (2017a,b) applied cellulolytic and xylanolytic enzyme preparations Viscozyme L and CeluStar XL for chokeberry pomace prior to and after SFE-CO2: the more effective Viscozyme L increased the yield of water-soluble fraction by 44%
113%, monosaccharide content by 12%
140%, TPC by 29%
41%, and radical scavenging capacity by 20%
39%. EAE with Viscozyme L at 40 C, pH 3.5, and 7 h also increased the yield of soluble compounds extracted from initial black currant pomace material, and the residues after SFE-CO2 and PLE with ethanol by 36.9%, 39.5%, and 31.6%, respectively (Oktay Basegmez et al., 2017).

5.3.2.6 Multistep biorefining processes Every type of berry pomace processing, for example, extraction, generates the main product and residues. The majority of this chapter has reviewed investigations focused on the main products, while the residues have remained neglected. For instance, the extraction and/or fractionation of berry pomace provides valuable products with the increased concentration of targeted groups of compounds; however, since the yield of the main product may be comparatively low, for example, in case of lipids approx. 3%
30%, large amounts of extraction residues still remain after pomace extraction. Consequently, a more holistic approach, preferably using biorefining and zero-waste concepts should be more widely applied for valorizing berry pomace. The International Energy Agency Bioenergy Task 42 on Biorefineries defined the concept of biorefining as: “a sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, and materials) and bioenergy (biofuels, power and/or heat).” Such a systematic approach facilitates the development of innovative processing schemes for the isolation and fractionation of berry pomace into high added-value food grade ingredients with plausible nutraceutical and pharmaceutical applications. A schematic diagram of the patented method (Arumughan et al., 2004) for processing sea buckthorn berries for oil, pulp, and juice is presented in the review of Zieli´nska and Nowak (2017) on the abundance of active ingredients in sea

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buckthorn oil; however, press residue in this scheme is used for producing seed oil and fibrous residue containing polar polyphenolic antioxidants. More recently the biorefining concept was applied for converting raspberry (Kryˇzeviˇci¯ut˙e et al., 2016), black currant (Oktay Basegmez et al., 2017), chokeberry (Grunovait˙e et al., 2016; Kitryt˙e et al., 2017a,b; Brazdauskas et al., 2016), bilberry (Ravi et al., 2018), sea buckthorn (Kitryt˙e et al., 2017a,b), guelder-rose berry (Kraujalis et al., 2017), cranberry, blackberry, and strawberry (unpublished data) pomaces into higher added-value ingredients by using multistep processes, including SFE-CO2, PLE, MHDG, UAE, BM, and EAE methods. It was demonstrated that different fractions containing high-value substances may be recovered from berry pomace by the combination of various methods. Kryˇzeviˇci¯ut˙e et al. (2016) demonstrated that two-step fractionation of raspberry pomace with SFE-CO2 and PLE provides high-value lipophilic and polar fractions, yielding approximately 15% and 25% of the pomace DM and containing PUFA-rich oils, tocopherols, and polyphenolic antioxidants: TPC and ORAC values of PLE ethanol extract were 208 mg GAE/g and 0.94 mmol TE/g, respectively. The PLE residue (approximately 60%), consisting of insoluble dietary fiber, proteins, minerals, and possibly some bound polyphenolics, was not further processed. Kraujalis et al. (2017) applied the same scheme for guelder-rose berries; SFE-CO2 yield of lipids at optimized parameters was 14.6%, while PLE of the residue with acetone, ethanol, and water gave 11.6%, 27.6%, and 30.7% of extract. Aqueous extracts demonstrated the highest TPC, DPPH , ABTS 1 scavenging, and ORAC values, 174.9 mg GAE/g, 267.4 mg TE/g, 602.3 mg TE/g, and 8.72 mmol TE/g, respectively. Kitryt˙e et al. (2017a,b) proposed a threestep fractionation scheme for the whole sea buckthorn pomace or separated seeds, including SFE-CO2, PLE with ethanol, and EAE, which generated several interesting products, namely PUFA- and tocopherol-rich oils, polyphenol-rich antioxidants, soluble sugar with additionally released phenolics and insoluble fiber fractions. Ravi et al. (2018) applied an innovative scheme, consisting of a combination of MHDG, UAE, and BM, for the separation of different fractions from bilberry pomace. The composition of solvent (0%
100% ethanol in water) in this study was selected based on COSMO-RS relative solubility of target polyphenols: MHDG extracts demonstrated the highest TPC (43.46 GAE/g), total flavonol content (TFC) (4.17 mg QE/g), TMA (12.19 mg delphinidin-3-O-glucoside equivalents/g of extract), and radical scavenging capacity (22.64 mg TE)g; whereas in UAE the highest TFC (10.41 mg QE/g) and TMA (12.19 D3GE mg/g) was present at 100% ethanol (Ravi et al., 2018). The integral flowchart of berry pomace biorefining is proposed in Fig. 5.2, which shows that a large number of processing methods and schemes may be applied for biorefining and valorizing berry pomace. Their selection depends on berry species, target products, technological upscaling, economics, and other aspects. G

5.4

G

Application of berry pomace products

The application of any new ingredients for human nutrition is first associated with its safety. The pomaces are generated from many edible berries, which have been consumed fresh and processed into various products during the entire history of modern humankind. Therefore the safety of berry pomace and its ingredients is not a complicated issue, unless materials and methods applied for their production do not imply any regulatory restrictions. For instance, the laws regulate the uses of hazardous organic solvents and particularly their residues in the final product. However, fruit seeds may contain some natural hazardous constituents as well. For instance, So´jka et al. (2013) in different mechanically separated fractions of black chokeberry pomace determined 7.8 2 185.7 mg/100 g DM cyanogenic glycoside amygdalin, the highest concentration being in the 1.25 2 2 mm fraction of seeds, which constituted 21.1% of the total pomace. Other important aspects in applying berry pomace origin ingredients in foods are related to their compatibility with different types of foods, the impact on product quality characteristics, required adjustments in technological processes, and others. The stability of added beneficial phytochemicals during thermal processing and storage should also be considered. So far as numerous ingredients may be obtained from berry pomace, it is important to decide what is the main goal of their application. Such a decision also would highly depend on economic and consumer acceptance issues. Most likely, increasing the healthiness and nutritive value of food fortified with pomace bioactive constituents is the most attractive aspect of their application. This issue has become particularly important in the era of functional foods. The food supplement (nutraceutical) and cosmetic industries are also wide and promising fields for the effective application of health-beneficial berry pomace constituents. Grape marc has been used for the production of fermented alcoholic beverages and distillates. Possibly fresh pomaces from other berries also could find this type of application; however, due to the low concentration of available sugars for microorganisms the studies on the fermentation of berry pomace for such purposes are not available, except for grapes. Bioconversion of vegetable residues via SSF for the generation of fruity food flavors was also noted as one possible practical implementation (Laufenberg et al., 2003); however, this possible application of berry pomaces, which is covered in this chapter, has not been reported.

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FIGURE 5.2 Integrated flowchart for berry pomace processing and valorization by using biorefining concept.

5.4.1

Applications of dried berry pomace

Dried and ground pomace powder may be considered as the simplest product for applications in foods. However, several problems are associated with the direct inclusion of such ingredients into the recipe: first, adverse effects of the additive on product quality; second, limited doses of berry phytochemicals, which are diluted and embedded with macrocomponents; and finally, their low accessibility from the solid pomace particles during gastrointestinal digestion. Sensory properties are very important in developing foods with the addition of berry pomace ingredients. Negative effects of pomace products may be the most important limiting factor for their application and particularly for the effective and acceptable doses of addition. Dried pomaces, depending on their composition and nutrients, usually exhibit some bitterness and sweetness, however, only a few studies have reported the sensory properties of berry pomace extracts. Nevertheless, some studies have reported the application of dried ground berry pomace in different foods, most often flour-based bakery products. Thus black currant pomace, used for partial (10%
30%) replacement of flour in crackers, significantly affected dynamic rheology in simulated baking, the extensibility and adhesiveness of dough and color, and the texture and sensory properties of the baked product; however, even 30% replacement produced acceptable crackers (Schmidt et al., 2018). The partial replacement of wheat flour by dried black currant pomace increased the water absorption of dough and dough development time, while after simulated baking, the dough with 30% pomace showed higher storage and loss moduli compared to the control and to the dough with lower levels of pomace additives (Struck et al., 2018). The authors concluded that 10% of black currant pomace is acceptable for obtaining satisfactory characteristics of dough, whereas higher levels would require gluten strength-increasing aids. Mokhtar et al. (2018) reported

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good technofunctional properties of goldenberry waste powder, including water absorption index (3.38 g/g), swelling index (5.24 mL/g), foaming capacity (4.09%), and stability (72.0%). Addition of 15%
25% (w/w) of ground wet blueberry and cranberry pomaces to Dijon-style mustard significantly increased TDF of mustards both from chemical extraction and in simulated gastrointestinal digestion, and radical scavenging capacity; however, sensory scores of pomace-fortified samples were significantly lower than the control (Davis et al., 2018). Bilberry pomace, which was dried at 40 C by hot-air and MWHA drying until 17% moisture content and then powdered, was incorporated in wholegrain rye flour-based extruded snacks at 10% or 25% with the purpose of enhancing TPC and potential for palatable sensory properties. MWHA drying reduced processing time by 40%; however, the retention of TPC and physical characteristics was independent on drying techniques (Ho¨glund et al., 2018). Incorporation of up to 30% sour cherry pomace into muffin formulas was reported to be acceptable: glucose responses to pomace-enriched muffins were significantly lower at 30, 45, and 60 min postprandial intervals, while the incremental peak glucose was 0.40 and 0.60 mmol/L lower than for control muffins (Bajerska et al., 2016). In addition, 30% additive increased TDF, TPC, and DPPH -scavenging capacity of serving size of the muffins (1700 kJ) 4.3, 9.9, and 11.3 times, respectively. Go´rna´s et al. (2016) used 5% of black currant, sour cherry, and raspberry pomace powder in a muffin recipe and reported that during baking at 140 C, 180 C, and 220 C, 36%
97% of anthocyanins were lost, while flavonols glycosides were quite stable. Moreover, the content of free ellagic acid was positively correlated with baking time, most likely due to the thermal hydrolysis of ellagitannins and ellagic acid glycosides. Greiby et al. (2017) estimated anthocyanin degradation kinetic parameters in cherry pomace with 25%, 41%, and 70% moisture during nonisothermal heating at 105 C and 127 C in a steam retort up to 125 min and measured their retention; the data could be used to design processes that will minimize the degradation of anthocyanins. Khanal et al. (2000) in order to enhance the contents of monomers and dimers at the expense of large molecular weight procyanidin oligomers and polymers applied extrusion for the mixtures of blueberry pomace with white sorghum flour (30:70): the treatment remarkably increased the monomer, dimer, and trimer contents and the highest monomer content obtained at 180 C and 150 rpm screw speed was 84% higher than the nonextruded control. However, extrusion processing reduced the total anthocyanin contents by 33%
42% and the authors concluded that additional treatments are needed to retain the pigments. Berry pomaces were also tested for animal feeding as ingredients for improving the nutritional quality of animal origin raw materials. Thus Juskiewicz et al. (2017) showed that the dietary application of dried black currant pomaces in the turkey diet increased the oxidative stability of meat from turkeys fed linseed oil. G

5.4.2

Applications of berry pomace extracts

For more effective application, pomace extracts should be processed into more specific ingredients, usually with higher concentrations of target compounds. A large variety of possible ingredients, which may be obtained by using different extraction/fractionation techniques, was revealed in one of the previous sections on multistep biorefining of pomace. Even mechanical separation into different particle size and/or specific gravity fractions may provide the products with increased protein, fat, and dietary fiber content (So´jka et al., 2013). The fractions with the increased amount of soluble pomace constituents may be produced by different extraction methods. The extracts obtained were tested in various products and their effects were evaluated. Swamp cranberry pomace extract prepared with 40% ethanol and added to minced pork meat at 2.5% dose reduced the number of pathogenic cells by four log cycles after 4 days of refrigeration storage; baked burgers obtained high ratings for color, taste, odor, juiciness, and overall acceptability that did not differ from the control samples (Schmidt et al., 2018). Hydroethanolic raspberry pomace extracts isolated by PLE effectively inhibited lipid oxidation during the prolonged storage of beef burgers and also demonstrated antimicrobial effects against Enterobacteriaceae, Brochothrix thermosphacta, Pseudomonas spp., and lactic acid bacteria, which are the most important spoilage microorganisms in raw meat (Kryˇzeviˇci¯ut˙e et al., 2017). However, the effects of lipophilic SFE-CO2 extracts had some prooxidative effects, most likely due to the addition of highly unsaturated oil. It is important that ethanolic extract at applied concentrations of up to 1% did not have any negative influence on sensory properties of beef burgers and may be considered as a promising natural additive for increasing the stability of meat products and enriching them with bioactive phytochemicals (Kryˇzeviˇci¯ut˙e et al., 2017). The addition of raspberry pomace ethanol extract (up to 2%) to pears/apples/yellow cherry plums and apples/black currants purees increased their TPC 3.28 and 2.25 times, respectively; TMA, ellagic acid and ellagitannins concentrations as well as antioxidant capacity also remarkably increased (Bobinait˙e et al., 2016b). However, higher levels of extract additives increased product bitterness and astringency, therefore the authors recommended not to exceed 1.6% of pomace extract in the purees.

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FIGURE 5.3 Effect of raspberry pomace extract additives (1%
5%) on appearance (left) and oxidative stability (right) of goat curd cheese (measured in Oxipres apparatus, showing absorption of oxygen at elevated temperature, which correlated with oxidation).

Aqueous extract from black currant pomace was used for developing a yogurt beverage with antidiabetic properties: at the end of a 4-week storage at 4 C α-amylase, β-glucosidase, and dipeptidyl peptidase IV inhibition was .61%, 62%, and 56%, respectively; whereas IC50 for .90% α-glucosidase inhibition was 0.20 mg/mL (Ni et al., 2018). “Ice” fruit tea and jellies prepared with the ethanol extracts from black currant and chokeberry pomace were characterized by a more natural aroma and fruit taste and more distinct color (Baranowski et al., 2009). Berry pomace extracts isolated with polar solvents and containing high amounts of phenolic antioxidants and anthocyanin pigments may be considered to be good candidates to replace synthetic food additives; however, the media for protective effects should be properly selected. For instance, crude extracts of Andes berry pomace was effective for controlling lipid oxidation of an O/W emulsion, however it did not inhibit lipid oxidation of the bulk oil (Ospina et al., 2019). Raspberry pomace ethanol extracts were added to the cottage-type goat curd cheese (unpublished results). The additive remarkably increased oxidative stability measured by the Oxipres methods and TPC; however it completely changed the product color (Fig. 5.3) and had strong effects on different sensory attributes, particularly bitterness, graininess, and fruity flavor notes. Consequently such cheese may be considered as a novel, specialty food product for selected consumers. The anthocyanin-rich fractions may find food applications as natural color additives as well (Wathon et al., 2019). Berry pomace may serve in the development of healthy ingredients in combination with food grade biopolymers. Recently Hoskin et al. (2019) produced freeze- or spray-dried polyphenol
protein particles from wild blueberry pomace extract complexed with wheat or chickpea flour or soy protein isolate and tested them in vitro; the extracts from particles significantly decreased reactive oxygen species production, downregulated the gene expression of inflammation markers (COX-2 and IL-b), inhibited phosphoenolpyruvate carboxykinase, and accelerated fibroblast cell migration. Phenolics extracts usually possess a bitter taste. The ethanol extracts of black currant pomace were perceived as most astringent and three flavonol glycosides (kaempferol-3-O-(60 -malonyl)glucoside, myricetin-3-O-galactoside, and an unknown kaempferol glycoside) were found to be the compounds contributing to astringency (Sandell et al., 2009). The extracts of crowberry pomace were the most bitter and astringent of the all assessed berry fractions; eight flavonol glycosides and two flavonol aglycones were reported to contribute particularly to bitterness and astringency (Laaksonen et al., 2011). The authors reported that the stepwise fractionation of crowberries, which are rich in different nutrients, gave products with substantial differences in their orosensory characteristics and composition and concluded that such processes may provide versatile and beneficial ways to exploit the berries and their pomaces in the food industry. The stability of phytochemicals in berry pomace extracts during storage also should be considered. Baranowski et al. (2009) reported that after a 6-month storage at 5 C
6 C without access to the light the content of TPC and anthocyanins in concentrated black currant and chokeberry pomace extracts decreased by 10% and 15% and 22% and 25%, respectively.

5.4.3

Encapsulation of pomace ingredients

Encapsulation has been widely used for increasing the stability of natural compounds during storage, improving their technological applicability (e.g., dosing), and enhancing bioaccessibility and for other purposes. Several studies have focused on developing encapsulated products with berry pomace constituents as well. Thus Cilek et al. (2012) investigated the effects of maltodextrin (MD) and gum Arabic (GA), ultrasonication, and core/coating ratio on the encapsulation of sour cherry pomace extract by FD: increasing GA ratio in the coating material increased process efficiency and the capsules prepared by sonication for 20 min and with a core to coating ratio of 1:20 were selected as the best

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conditions. Luca et al. (2013) encapsulated extracted phenolic powder (EPP) and purified extracted phenolic powder (PEPP), which were produced from sour cherry pomace, in 10% MD or 8% MD 1 2% GA: as a result of purification, encapsulation efficiency increased from 86.07%
88.45% to 98.01%
98.29%. Afterward a positive effect of encapsulation on storage and baking stability as well as in vitro digestibility was demonstrated; for instance, during storage at 43% relative humidity the loss of TPC in EPP and PEPP was 10% and 15%, respectively; while under the same conditions, uncoated pomace powders lost 37% and 43% of TPC, respectively. In addition, encapsulation was effective in the masking of the flavor of the phenolic powders when capsules were incorporated into cakes (Luca et al., 2014). ˇ Tumbas Saponjac et al. (2017) demonstrated that soy proteins were more effective than whey proteins for encapsulating hydroethanolic cherry pomace extract in terms of retention of TPC, TMA, and antioxidant activity during storage. They incorporated the encapsulated cherry pomace extracts into cookies, by replacing 10% and 15% (WE10/15 and SE10/15) of flour: retention of polyphenols and anthocyanins after cooking was 11% (WE10)
43% (SE10) and 19% (WE15)
59% (SE10), while after 4 months of storage TPC of WE10, SE10, WE15, and SE15 slightly increased (by 23.47%, 42.00%, 4.12%, and 1.16%, respectively), TMA (by 67.92%, 64.33%, 58.75%, and 35.91%) and antioxidant activity decreased (by 9.31%, 24.30%, 11.41%, and 12.98%). Color parameters of cookies were influenced by the color ˇ of encapsulates, however fortified cookies received satisfactory sensory acceptance as well (Tumbas Saponjac et al., 2016). Hala´sz and Cso´ka (2018) immobilized black chokeberry pomace extract in chitosan for colorimetric pH indicator film application; the indicator films maintained their integrity even at acidic pH, which was attributed to the interactions between the polymer chains and the phenolic components of the extract. Kurek et al. (2018) developed chitosan-based smart films with (1%
4% w/v) of blueberry and blackberry pomace extracts as active agents and showed that antioxidant potential was not diminished after the film production; while the chitosan matrix was not significantly changed regarding permeability to oxygen and mechanical properties. Water vapor permeability slightly decreased, and visible and significant color changes of dry pH indicator films occurred with changing pH (Kurek et al., 2018).

5.5

Conclusion

It is evident that numerous valuable food grade ingredients may be produced from berry pomace. Such ingredients may find wide applications for increasing nutritive value and health benefits of foods, for developing new ingredients for functional foods, nutraceuticals, natural food additives, and cosmetics. A large body of scientific and technological knowledge on the composition and processing of berry pomace has been generated during last two decades and it may serve for developing and upscaling laboratory-tested methods for industrial implementation. On the other hand, the currently available information is not sufficient for developing the most effective berry pomace processing schemes for their valorization. From this point of view, the wider use of the biorefining concept leading to “zero-waste” technologies may be considered as the most promising trend for future investigations and applications. The effectiveness of applying the biorefining concept has already been proven in multistep processing of various berry pomaces.

Acknowledgments This research is funded by the European Regional Development Fund according to the supported activity “Research Projects Implemented by World-class Researcher Groups” under Measure No. 01.2.2-LMT-K-718.

References Aaby, K., Grimmer, S., Holtung, L., 2013. Extraction of phenolic compounds from bilberry (Vaccinium myrtillus L.) press residue: effects on phenolic composition and cell proliferation. LWT Food Sci. Technol. 54 (1), 257
264. Acosta-Estrada, B.A., Gutie´rrez-Uribe, J.A., Serna-Saldı´var, S.O., 2014. Bound phenolics in foods, a review. Food Chem. 152, 46
55. Adil, ˙I.H., Yener, M.E., Bayındırlı, A., 2008. Extraction of total phenolics of sour cherry pomace by high pressure solvent and subcritical fluid and determination of the antioxidant activities of the extracts. Sep. Sci. Technol. 43, 1091
1110. Aizpurua-Olaizola, O., Ormazabal, M., Vallejo, A., Olivares, M., Navarro, P., Etxebarria, N., et al., 2015. Optimization of supercritical fluid consecutive extractions of fatty acids and polyphenols from Vitis vinifera grape wastes. J. Food Sci. 80 (1), E101
E107. Arshadi, M., Attard, T.M., Bogel-Lukasik, R.M., Brncic, M., da Costa Lopes, A.M., Finell, M., et al., 2016. Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain. Green Chem. 18, 6160
6204. Arumughan, C., Venugopalan, V.V., Ranjith, A., Sarinkumar, K., Mangalagowri, P., Sawhney, R.C., et al., 2004. A novel green approach to the integrated processing of sea buckthorn berries for therapeutic and nutraceutical values. Indian Patent 648/DEL. Bajerska, J., Mildner-Szkudlarz, S., Go´rna´s, P., Seglina, D., 2016. The effects of muffins enriched with sour cherry pomace on acceptability, glycemic response, satiety and energy intake: a randomized crossover trial. J. Sci. Food Agric. 96, 2486
2493.

Berries Chapter | 5

121

Bakowska-Barczak, A.M., Schieber, A., Kolodziejczyk, P., 2009. Characterization of Canadian black currant (Ribes nigrum L.) seed oils and residues. J. Agric. Food Chem. 57 (24), 11528
11536. Baranowski, K., Baca, E., Salamon, A., Michałowska, D., Meller, D., Kara´s, M., 2009. Possibilities of retrieving and making a practical use of pheno´ Nauka. Technologia. Jako´sc´ 4 (65), ˙ lic compounds from the waste products: black currant and chokeberry pomace and spent hops. ZYWNO S´ C. 100
109. Be´lafi-Bako´, K., Cserje´si, P., Besze´des, S., Csana´di, Z., Hodu´r, C., 2012. Berry pectins: microwave-assisted extraction and rheological properties. Food Bioprocess Technol. 5, 1100
1105. Beres, C., Costa, G.N.S., Cabezudo, I., da Silva-James, N.K., Teles, A.S.C., Cruz, A.P.G., et al., 2017. Towards integral utilization of grape pomace from winemaking process: a review. Waste Manag. 68, 581
594. Bobinait˙e, R., Viˇskelis, P., Buskien˙e, L., 2010. Extraction of phenolic compounds from raspberry press cake. Scientific Works of the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry and Lithuanian University of Agriculture. Sodininkyst˙e Darˇzininkyst˙e 29 (2), 19
31. Bobinait˙e, R., Viˇskelis, P., Venskutonis, P.R., 2012. Variation of total phenolics, anthocyanins, ellagic acid and radical scavenging capacity in various raspberry (Rubus spp.) cultivars. Food Chem. 132, 1495
1501. ˇ Bobinait˙e, R., Viˇskelis, P., Sarkinas, A., Venskutonis, P.R., 2013. Phytochemical composition, antioxidant and antimicrobial properties of raspberry fruit, pulp, and marc extracts. CyTA J. Food 11 (4), 334
342. Bobinait˙e, R., Viˇskelis, P., Venskutonis, P.R., 2016a. Chemical composition of raspberry (Rubus spp.) cultivars. In: Simmonds, M.S.J., Preedy, V.R. (Eds.), Nutritional Composition of Fruit Cultivars. Academic Press, pp. 713
731. ˇ Mieˇzelien˙e, A., Alenˇcikien˙e, G., Venskutonis, P.R., 2016b. Raspberry marc extracts increase antioxidative Bobinait˙e, R., Viˇskelis, P., Bobinas, C., potential, ellagic acid, ellagitannin and anthocyanin concentrations in fruit purees. LWT Food Sci. Technol. 66, 460
467. Brazdauskas, T., Montero, L., Venskutonis, P.R., Iban˜ez, E., Herrero, M., 2016. Downstream valorization and comprehensive two-dimensional liquid chromatography-based chemical characterization of bioactives from black chokeberries (Aronia melanocarpa) pomace. J. Chromatogr. A 4168, 126
135. Buchert, J., Koponen, J.M., Suutarinen, M., Mustranta, A., Lille, M., To¨rro¨nen, R., et al., 2005. Effect of enzyme-aided pressing on anthocyanin yield and profiles in bilberry and black currant juices. J. Sci. Food Agric. 85 (15), 2548
2556. Caillet, S., Cote, J., Sylvain, J.F., Lacroix, M., 2012. Antimicrobial effects of fractions from cranberry products on the growth of seven pathogenic bacteria. Food Control 23 (2), 419
428. Chemat, F., Rombaut, N., Sicaire, A.G., Meullemiestre, A., Fabiano-Tixier, A.S., Abert-Vian, M., 2017. Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review. Ultrason. Sonochem. 34, 540
560. Ciccoritti, R., Paliotta, M., Centioni, L., Mencarelli, F., Carbone, K., 2018. The effect of genotype and drying condition on the bioactive compounds of sour cherry pomace. Eur. Food Res. Technol. 244, 635
645. Cilek, B., Luca, A., Hasirci, V., Sahin, S., Sumnu, G., 2012. Microencapsulation of phenolic compounds extracted from sour cherry pomace: effect of formulation, ultrasonication time and core to coating ratio. Eur. Food Res. Technol. 235, 587
596. Da Fonseca Machado, A.P., Duarte Pereira, A.L., Barbero, G.F., Martı´nez, J., 2017. Recovery of anthocyanins from residues of Rubus fruticosus, Vaccinium myrtillus and Eugenia brasiliensis by ultrasound assisted extraction, pressurized liquid extraction and their combination. Food Chem. 231, 1
10. Davis, L., Jung, J., Colonna, A., Hasenbeck, A., Gouw, V., Zhao, Y.Y., 2018. Quality and consumer acceptance of berry fruit pomace-fortified specialty mustard. J. Food Sci. 83 (7), 1921
1932. Dobson, G., Shrestha, M., Hilz, H., Karjalainen, R., McDougall, G., Stewart, D., 2012. Lipophilic components in black currant seed and pomace extracts. Eur. J. Lipid Sci. Technol. 114, 575
582. Dulf, F.V., Andrei, S., Bunea, A., Socaciu, C., 2012. Fatty acid and phytosterol contents of some Romanian wild and cultivated berry pomaces. Chem. Papers 66 (10), 925
934. Dulf, F.V., Vodnar, D.C., Dulf, E.H., Tosa, M.I., 2015. Total phenolic contents, antioxidant activities, and lipid fractions from berry pomaces obtained by solid-state fermentation of two Sambucus species with Aspergillus niger. J. Agric. Food Chem. 63 (13), 3489
3500. Dulf, F.V., Vodnar, D.C., Dulf, E.-H., Diaconeasa, Z., Socaciu, C., 2018. Liberation and recovery of phenolic antioxidants and lipids in chokeberry (Aronia melanocarpa) pomace by solid-state bioprocessing using Aspergillus niger and Rhizopus oligosporus strains. LWT Food Sci. Technol. 87, 241
249. Ector, B.J., Magee, J.B., Hegwood, C.P., Coign, M.J., 1996. Resveratrol concentration in muscadine berries, juice, pomace, purees, seeds, and wines. Am. J. Enol. Viticult. 47 (1), 57
62. Eliasson, L., Labrosse, L., Ahrne´, L., 2017. Effect of drying technique and particle size of bilberry press cake on the extraction efficiency of anthocyanins by pressurized carbon dioxide extraction. LWT Food Sci. Technol. 85, 510
516. Erythropel, H.C., Zimmerman, J.B., de Winter, T.M., Petitjean, L., Melnikov, F., Lam, C.H., et al., 2018. The Green ChemisTREE: 20 years after taking root with the 12 principles. Green Chem. 20, 1929
1961. Flores, F.P., Singh, R.K., Kerr, W.L., Pegg, R.B., Kong, F., 2013. Antioxidant and enzyme inhibitory activities of blueberry anthocyanins prepared using different solvents. J. Agric. Food Chem. 61, 4441
4447. Galanakis, C.M., 2012. Recovery of high added-value components from food wastes: conventional, emerging technologies and commercialized applications. Trends Food Sci. Technol. 26, 68
87. Galanakis, C.M., 2013. Emerging technologies for the production of nutraceuticals from agricultural by-products: a viewpoint of opportunities and challenges. Food Bioprod. Process. 91, 575
579.

122

Valorization of Fruit Processing By-products

Garcia-Lomillo, J., Gonzalez-San Jose, M.L., 2017. Applications of wine pomace in the food industry: approaches and functions. Compr. Rev. Food Sci. F 16 (1), 3
22. Go¨kmen, V., Serpen, A., Fogliano, V., 2009. Direct measurement of the total antioxidant capacity of foods: the ‘QUENCHER’ approach. Trends Food Sci. Technol. 20, 278
288. Go´rna´s, P., Juh¸neviˇca-Radenkova, K., Radenkovs, V., Miˇsina, I., Pugajeva, I., Soliven, A., et al., 2016. The impact of different baking conditions on the stability of the extractable polyphenols in muffins enriched by strawberry, sour cherry, raspberry or black currant pomace. LWT Food Sci. Technol. 65, 946
953. Greiby, I., Mishra, D.K., Dolan, K.D., Siddiq, M., 2017. Inverse method to estimate anthocyanin degradation kinetic parameters in cherry pomace during non-isothermal heating. J. Food Eng. 198, 54
62. Grunovait˙e, L., Pukalskien˙e, M., Pukalskas, A., Venskutonis, P.R., 2016. Fractionation of black chokeberry pomace into functional ingredients using high pressure extraction methods and evaluation of their antioxidant capacity and chemical composition. J. Funct. Foods 24, 85
86. Gustinelli, G., Eliasson, L., Svelander, C., Alminger, M., Ahrne´, L., 2018. Supercritical CO2 extraction of bilberry (Vaccinium myrtillus L.) seed oil: fatty acid composition and antioxidant activity. J. Supercrit. Fluid. 135, 91
97. Ha¨kkinen, S., Heinonen, M., Ka¨renlampi, S., To¨rro¨nen, R., Ruuskanen, J., To¨rro¨nen, R., 1999. Screening of selected favonoids and phenolic acids in 19 berries. Food Res. Int. 32, 345
353. Hala´sz, K., Cso´ka, L., 2018. Black chokeberry (Aronia melanocarpa) pomace extract immobilized in chitosan for colorimetric pH indicator film application. Food Pack. Shelf Life 16, 185
193. He, B., Zhang, L.-L., Yue, X.-Y., Liang, J., Jiang, J., Gao, X.-L., et al., 2016. Optimization of ultrasound-assisted extraction of phenolic compounds and anthocyanins from blueberry (Vaccinium ashei) wine pomace. Food Chem. 204, 70
76. Hilz, H., Bakx, E.J., Schols, H.A., Voragen, A.G.J., 2005. Cell wall polysaccharides in black currants and bilberries—characterisation in berries, juice, and press cake. Carbohydr. Polym. 59, 477
488. Hilz, H., Williams, P., Doco, T., Schols, H.A., Voragen, A.G.J., 2006. The pectic polysaccharide rhamnogalacturonan II is present as a dimer in pectic populations of bilberries and black currants in muro and in juice. Carbohydr. Polym. 65, 521
528. Ho¨glund, E., Eliasson, L., Oliveira, G., Almli, V.L., Sozer, N., Alminger, M., 2018. Effect of drying and extrusion processing on physical and nutritional characteristics of bilberry press cake extrudates. LWT Food Sci. Technol. 92, 422
428. Holtung, L., Grimmer, S., Aaby, K., 2012. Effect of processing of black currant press-residue on polyphenol composition and cell proliferation. J. Agric. Food Chem. 59, 3632
3640. Hoskin, R.T., Xiong, J., Esposito, D.A., Lila, M.A., 2019. Blueberry polyphenol-protein food ingredients: the impact of spray drying on the in vitro antioxidant activity, anti-inflammatory markers, glucose metabolism and fibroblast migration. Food Chem. 280, 187
194. ˇ ˇ ´ , A., Malvis, A., Sima, Jablonsky´, M., Skulcova J., 2018. Extraction of value-added components from food industry based and agro-forest biowastes by deep eutectic solvents. J. Biotechnol. 282, 46
66. Jara-Palacios, M.J., Santisteban, A., Gordillo, B., Hernanz, D., Heredia, F.J., Escudero-Gilete, M.L., 2019. Comparative study of red berry pomaces (blueberry, red raspberry, red currant and blackberry) as source of antioxidants and pigments. Eur. Food Res. Technol. 245, 1
9. ˇ Jazi´c, M., Kukri´c, Z., Vuli´c, J., Cetojevi´ c-Simin, D., 2019. Polyphenolic composition, antioxidant and antiproliferative effects of wild and cultivated blackberries (Rubus fruticosus L.) pomace. Int. J. Food Sci. Technol. 54 (1), 194
201. Juskiewicz, J., Jankowski, J., Zielinski, H., Zdunczyk, Z., Mikulski, D., Antoszkiewicz, Z., et al., 2017. The fatty acid profile and oxidative stability of meat from turkeys fed diets enriched with n-3 polyunsaturated fatty acids and dried fruit pomaces as a source of polyphenols. PLoS One 12 (1), Art. No. e0170074. Kammerer, D.R., Kammerer, J., Valet, R., Carle, R., 2014. Recovery of polyphenols from the by-products of plant food processing and application as valuable food ingredients. Food Res. Int. 65, 2
12. Kapasakalidis, P.G., Rastall, R.A., Gordon, M.H., 2006. Extraction of polyphenols from processed black currant (Ribes nigrum L.) residues. J. Agric. Food Chem. 54, 4016
4021. Kapasakalidis, P.G., Rastall, R.A., Gordon, M.H., 2009. Effect of a cellulase treatment on extraction of antioxidant phenols from black currant (Ribes nigrum L.) pomace. J. Agric. Food Chem. 57, 4342
4351. Kerbstadt, S., Eliasson, L., Mustafa, A., Ahrne´, L., 2015. Effect of novel drying techniques on the extraction of anthocyanins from bilberry press cake using supercritical carbon dioxide. Innov. Food Sci. Emerg. 29, 209
214. Khanal, R.C., Howard, L.R., Prior, R.L., 2000. Influence of extrusion processing on procyanidin composition and total anthocyanin contents of blueberry pomace. J. Food Sci. 74, H52
H58. ˇ Kitryt˙e, V., Kraujalien˙e, V., Sulni¯ ut˙e, V., Venskutonis, P.R., 2017a. Chokeberry pomace valorization into food ingredients by enzyme-assisted extraction: process optimization and product characterization. Food Bioprod. Proc. 105, 36
50. ˇ Kitryt˙e, V., Povilaitis, D., Kraujalien˙e, V., Sulni¯ ut˙e, V., Pukalskas, A., Venskutonis, P.R., 2017b. Fractionation of sea buckthorn pomace and seeds into valuable components by using high pressure and enzyme-assisted extraction methods. LWT Food Sci. Technol. 85 (B), 534
538. Klavins, L., Kviesis, J., Klavins, M., 2017. Comparison of methods of extraction of phenolic compounds from American cranberry (Vaccinium macrocarpon L.) press residues. Agron. Res. 15 (2), 1316
1330. Klavins, L., Kviesis, J., Nakurte, I., Klavins, M., 2018. Berry press residues as a valuable source of polyphenolics: extraction optimisation and analysis. LWT Food Sci. Technol. 93, 583
591. Kołodziejczyka, K., So´jka, M., Abadias, M., Vin˜as, I., Guyot, S., Baron, A., 2013. Polyphenol composition, antioxidant capacity, and antimicrobial activity of the extracts obtained from industrial sour cherry pomace. Ind. Crops Prod. 51, 279
288.

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123

Koponen, J.M., Happonen, A.M., Auriola, S., Kontkanen, H., Buchert, J., Poutanen, K.S., et al., 2008. Characterization and fate of black currant and bilberry flavonols in enzyme-aided processing. J. Agric. Food Chem. 56 (9), 3136
3144. Kosmala, M., Milala, J., Kołodziejczyk, K., Markowski, J., Mieszczakowska, M., Ginies, et al., 2009. Characterization of cell wall polysaccharides of cherry (Prunus cerasus var. Schattenmorelle) fruit and pomace. Plant Foods Hum. Nutr. 64, 279
285. Kosmala, M., Kołodziejczyk, K., Markowski, J., Mieszczakowska, M., Ginies, C., Renard, C.M.G.C., 2010. Co-products of black-currant and apple juice production: hydration properties and polysaccharide composition. LWT Food Sci. Technol. 43, 173
180. Kraujalis, P., Kraujalien˙e, V., Kazernaviˇci¯ut˙e, R., Venskutonis, P.R., 2017. Supercritical carbon dioxide and pressurized liquid extraction of valuable ingredients from Viburnum opulus pomace and berries and evaluation of product characteristics. J. Supercrit. Fluid 122, 99
108. ˇ Kraujalyt˙e, V., Venskutonis, P.R., Pukalskas, A., Cesonien˙ e, L., Daubaras, R., 2013. Antioxidant properties and polyphenolics composition of fruits from different European cranberry bush (Viburnum opulus L.) genotypes. Food Chem. 141, 3695
3702. ˇ Kraujalyt˙e, V., Venskutonis, P.R., Pukalskas, A., Cesonien˙ e, L., Daubaras, R., 2015. Antioxidant properties, phenolic composition and potentiometric sensor array evaluation of commercial and new blueberry (Vaccinium corymbosum) and bog blueberry (Vaccinium uliginosum) genotypes. Food Chem. 188, 583
590. Kryˇzeviˇci¯ut˙e, N., Kraujalis, P., Venskutonis, P.R., 2016. Optimization of high pressure extraction processes for the separation of raspberry pomace into lipophilic and hydrophilic fractions. J. Supercrit Fluids 108, 61
68. Kryˇzeviˇcu¯ t˙e, N., Jaime, I., Diez, A.M., Rovira, J., Venskutonis, P.R., 2017. Effect of raspberry pomace extracts isolated by high pressure extraction on the quality and shelf-life of beef burgers. Int. J. Food Sci. Technol. 52 (8), 1852
1861. ˇ cetar, M., Uzelac, V.D., Gali´c, K., 2018. Development and evaluation of a novel antioxidant and pH indicaKurek, M., Garofuli´c, I.E., Baki´c, M.T., Sˇ tor film based on chitosan and food waste sources of antioxidants. Food Hydrocolloid. 84, 238
246. Laaksonen, O., Sandell, M., Ja¨rvinen, R., Kallio, H., 2011. Orosensory contributing compounds in crowberry (Empetrum nigrum) press-byproducts. Food Chem. 124, 1514
1524. Landbo, A.-K., Meyer, A.S., 2001. Enzyme-assisted extraction of antioxidative phenols from black currant juice press residues (Ribes nigrum). J. Agric. Food Chem. 49, 3169
3177. Lapornik, B., Proˇsek, M., Golc Wondra, A., 2005. Comparison of extracts prepared from plant by-products using different solvents and extraction time. J. Food Eng. 71, 214
222. Laroze, L., Soto, C., Zu´n˜iga, M.E., 2010. Phenolic antioxidants extraction from raspberry wastes assisted by-enzymes. Electron. J. Biotechnol. 13, 6. Available from: http://dx.doi.org/10.2225/vol13-issue6-fulltext-12. Laufenberg, G., Kunz, B., Nystroem, M., 2003. Transformation of vegetable waste into value added products: (A) the upgrading concept; (B) practical implementation. Bioresour. Technol. 87 (2), 167
198. Li, Q.Q., Wang, J.K., Shahidi, F., 2016a. Chemical characteristics of cold-pressed blackberry, black raspberry, and blueberry seed oils and the role of the minor components in their oxidative stability. J. Agric. Food Chem. 64 (26), 5410
5416. Li, X., Chen, F., Li, S., Jia, J., Gu, H., Yang, L., 2016b. An efficient homogenate-microwave-assisted extraction of flavonols and anthocyanins from black currant marc: optimization using combination of Plackett-Burman design and Box-Behnken design. Ind. Crops Prod. 94, 834
847. Li, F., Chen, G., Zhang, B., Fu, X., 2017. Current applications and new opportunities for the thermal and non-thermal processing technologies to generate berry product or extracts with high nutraceutical contents. Food Res. Int. 100, 19
30. Luca, A., Cilek, B., Hasirci, V., Sahin, S., Sumnu, G., 2013. Effect of degritting of phenolic extract from sour cherry pomace on encapsulation efficiency—production of nano-suspension. Food Bioprocess Technol. 6, 2494
2502. Luca, A., Cilek, B., Hasirci, V., Sahin, S., Sumnu, G., 2014. Storage and baking stability of encapsulated sour cherry phenolic compounds prepared from micro- and nano-suspensions. Food Bioprocess Technol. 7, 204
211. Mayer-Miebach, E., Adamiuk, M., Behsnilian, D., 2012. Stability of chokeberry bioactive polyphenols during juice processing and stabilization of a polyphenol-rich material from the by-product. Agriculture 2, 244
258. Manninen, P., Pakarinen, J., Kallio, H., 1997. Large-scale supercritical carbon dioxide extraction and supercritical carbon dioxide countercurrent extraction of cloudberry seed oil. J. Agric. Food Chem. 45, 2533
2538. McDougall, N.R., Beames, R.M., 1994. Composition of raspberry pomace and its nutritive-value for monogastric animals. Anim. Feed Sci. Technol. 45, 139
148. Mokhtar, S.M., Swailam, H.M., El-Sayed Embaby, H., 2018. Physicochemical properties, nutritional value and techno-functional properties of goldenberry (Physalis peruviana) waste powder concise title. Food Chem. 248, 1
7. Muhlack, R.A., Potumarthi, R., Jeffery, D.W., 2018. Sustainable wineries through waste valorisation: a review of grape marc utilisation for valueadded products. Waste Manag. 72, 99
118. Nawirska, A., Kwa´sniewska, M., 2005. Dietary fibre fractions from fruit and vegetable processing waste. Food Chem. 91, 221
225. Naziri, E., Nenadis, N., Mantzouridou, F.T., Tsimidou, M.Z., 2014. Valorization of the major agrifood industrial by-products and waste from Central Macedonia (Greece) for the recovery of compounds for food applications. Food Res. Int. 65, 350
358. Ni, H., Hayes, H.E., Stead, D., Raikos, V., 2018. Incorporating salal berry (Gaultheria shallon) and black currant (Ribes nigrum) pomace in yogurt for the development of a beverage with antidiabetic properties. Heliyon 4 (10), Art. No. e00875. ˇ Oktay Basegmez, H.I., Povilaitis, D., Kitryt˙e, V., Kraujalien˙e, V., Sulni¯ ut˙e, V., Alasalvar, C., et al., 2017. Biorefining of black currant pomace into high value functional ingredients using supercritical CO2, pressurized liquid and enzyme assisted extractions. J. Supercrit. Fluids 124, 10
19. ´ ., Toloza-Daza, H., Narva´ez-Cuenca, C.E., 2019. Utilization of fruit pomace, overripe fruit, and bush Ospina, M., Montan˜a-Oviedo, K., Dı´az-Duque, A pruning residues from Andes berry (Rubus glaucus Benth) as antioxidants in an oil in water emulsion. Food Chem. 281, 114
123.

124

Valorization of Fruit Processing By-products

Oszmia´nski, J., Wojdylo, A., 2005. Aronia melanocarpa phenolics and their antioxidant activity. Eur. Food Res. Technol. 221, 809
813. Pap, N., Besze´des, S., Pongra´cz, E., Myllykoski, L., Ga´bor, M., Gyimes, E., et al., 2013. Microwave-assisted extraction of anthocyanins from black currant marc. Food Bioprocess Technol. 6, 2666
2674. Parry, J., Su, L., Luther, M., Zhou, K.Q., Yurawecz, M.P., Whittaker, P., et al., 2005. Fatty acid composition and antioxidant properties of coldpressed marionberry, boysenberry, red raspberry, and blueberry seed oils. J. Agric. Food Chem. 53 (3), 566
573. Passos, H., Freire, M.G., Coutinho, J.A.P., 2014. Ionic liquid solutions as extractive solvents for value-added compounds from biomass. Green Chem. 16, 4786
4815. Peixoto, C.M., Dias, M.I., Alves, M.J., Calhelha, R.C., Barros, L., Pinho, S.P., et al., 2018. Grape pomace as a source of phenolic compounds and diverse bioactive properties. Food Chem. 253, 132
138. Perussello, C.A., Zhang, Z.H., Marzocchella, A., Tiwari, B.K., 2017. Valorization of apple pomace by extraction of valuable compounds. Compr. Rev. Food Sci. Food Saf. 16 (5), 776
796. Pieszka, M., Gogol, P., Pietras, M., Pieszka, M., 2015. Valuable components of dried pomaces of chokeberry, black currant, strawberry, apple and carrot as a source of natural antioxidants and nutraceuticals in the animal diet. Ann. Anim. Sci. 15, 475
491. ˇ Piskernik, S., Vidrih, R., Demˇsar, L., Koron, D., Rogelj, M., Zontar, T.P., 2018. Fatty acid profiles of seeds from different Ribes species. LWT Food Sci. Technol. 98, 424
427. Radoˇcaj, O., Vujasinovi´c, V., Dimi´c, E., Basi´c, Z., 2014. Blackberry (Rubus fruticosus L.) and raspberry (Rubus idaeus L.) seed oils extracted from dried press pomace after longterm frozen storage of berries can be used as functional food ingredients. Eur. J. Lipid Sci. Technol. 116 (8), 1015
1024. Ravi, H.K., Breil, C., Vian, M.A., Chemat, F., Venskutonis, P.R., 2018. Biorefining of bilberry (Vaccinium myrtillus L.) pomace using microwave hydrodiffusion and gravity, ultrasound-assisted, and bead-milling extraction. ACS Sustain. Chem. Eng. 6, 4185
4193. Sandell, M., Laaksonen, O., Ja¨rvinen, R., Rostiala, N., Pohjanheimo, T., Tiitinen, K., et al., 2009. Orosensory profiles and chemical composition of black currant (Ribes nigrum) juice and fractions of press residue. J. Agric. Food Chem. 57, 3718
3728. Schieber, A., Stintzing, F.C., Carle, R., et al., 2001. By-products of plant food processing as a source of functional compounds—recent developments. Trends Food Sci. Technol. 12, 401
413. Schmidt, C., Geweke, I., Struck, S., Zahn, S., Rohm, H., 2018. Black currant pomace from juice processing as partial flour substitute in savoury crackers: dough characteristics and product properties. Int. J. Food Sci. Technol. 53, 237
245. Simsek, M., Sumnu, G., Sahin, S., 2012. Microwave assisted extraction of phenolic compounds from sour cherry pomace. Sep. Sci. Technol. 47, 1248
1254. Skrede, G., Wrolstad, R.E., Durst, R.W., 2000. Changes in anthocyanins and polyphenolics during juice processing of highbush blueberries (Vaccinium corymbosum L.). J. Food Sci. 65, 357
364. So´jka, M., Kro´l, B., 2009. Composition of industrial seedless black currant pomace. Eur. Food Res. Technol. 228, 597
605. So´jka, M., Kołodziejczyk, K., Milala, J., 2013. Polyphenolic and basic chemical composition of black chokeberry industrial by-products. Ind. Crops Prod. 51, 77
86. Stobnicka, A., Gniewosz, M., 2018. Antimicrobial protection of minced pork meat with the use of Swamp Cranberry (Vaccinium oxycoccos L.) fruit and pomace extracts. J. Food Sci. Technol. 55 (1), 62
71. Stoica-Guzun, A., Paˆrvulescu, O.C., Bro¸steanu, A., Chira, N., Stroescu, M., Dobre, T., 2018. Influence of sea buckthorn pomace pre-treatment and drying conditions on the drying kinetics, quantity and quality of seed oil. J. Food Nutr. Res. 57 (4), 363
372. Struck, S., Straube, D., Zahn, S., Rohm, H., 2018. Interaction of wheat macromolecules and berry pomace in model dough: rheology and microstructure. J. Food Eng. 223, 109
115. ˇ ´ ˇ Tumbas Saponjac, V., Cetkovi´ c, G., Canadanovi´ c-Brunet, J., Pajin, B., Djilas, S., Petrovi´c, J., et al., 2016. Sour cherry pomace extract encapsulated in whey and soy proteins: incorporation in cookies. Food Chem. 207, 27
33. ˇ ´ ˇ Tumbas Saponjac, V., Cetkovi´ c, G., Canadanovi´ c-Brunet, J., Ðilas, S., Pajin, B., Petrovi´c, J., et al., 2017. Encapsulation of sour cherry pomace extract by freeze drying: characterization and storage stability. Acta Chim. Slov. 64, 283
289. Van Hoed, V., Barbouche, I., De Clercq, N., Dewettinck, K., Slah, M., Leber, E., et al., 2011. Influence of filtering of cold pressed berry seed oils on their antioxidant profile and quality characteristics. Food Chem. 127 (4), 1848
1855. Wajs-Bonikowska, A., Stobiecka, A., Bonikowski, R., Krajewska, A., Sikora, M., Kula, J., 2017. A comparative study on composition and antioxidant activities of supercritical carbon dioxide, hexane and ethanol extracts from blackberry (Rubus fruticosus) growing in Poland. J. Sci. Food Agric. 97, 3576
3583. Wathon, M.H., Beaumont, N., Benohoud, M., Blackburn, R.S., Rayner, C.M., 2019. Extraction of anthocyanins from Aronia melanocarpa skin waste as a sustainable source of natural colorants. Color. Technol. 135 (1), 5
16. White, B.L., Howard, L.R., Prior, R.L., 2010. Release of bound procyanidins from cranberry pomace by alkaline hydrolysis. J. Agric. Food Chem. 58, 7572
7579. White, B.L., Howard, L.R., Prior, R.L., 2011. Impact of different stages of juice processing on the anthocyanin, flavonol, and procyanidin contents of cranberries. J. Agric. Food Chem. 59, 4692
4698. Wijngaard, H., Hossain, M.B., Rai, D.K., Brunton, N., 2012. Techniques to extract bioactive compounds from food by-products of plant origin. Food Res. Int. 46, 505
513. Wo´zniak, Ł., Marszałek, K., Ska˛pska, S., 2016. Extraction of phenolic compounds from sour cherry pomace with supercritical carbon dioxide: impact of process parameters on the composition and antioxidant properties of extracts. Sep. Sci. Technol. 51 (9), 1472
1479.

Berries Chapter | 5

125

Yakimishen, R., Cenkowski, S., Muir, W.E., 2005. Oil recoveries from sea buckthorn seeds and pulp. Appl. Eng. Agric. 21 (6), 1047
1055. Yammine, S., Brianceau, S., Manteau, S., Turk, M., Ghidossi, R., Vorobiev, E., et al., 2018. Extraction and purification of high added value compounds from by-products of the winemaking chain using alternative/nonconventional processes/technologies. Crit. Rev. Food Sci. Nutr. 58 (8), 1375
1390. Yang, B., Ahotupa, M., Ma¨a¨tta¨, P., Kallio, H., 2011. Composition and antioxidative activities of supercritical CO2-extracted oils from seeds and soft parts of northern berries. Food Res. Int. 44 (7), 2009
2017. Yılmaz, F.M., Karaaslan, M., Vardin, H., 2015. Optimization of extraction parameters on the isolation of phenolic compounds from sour cherry (Prunus cerasus L.) pomace. J. Food Sci. Technol. 52 (5), 2851
2859. Zieli´nska, A., Nowak, I., 2017. Abundance of active ingredients in sea-buckthorn oil. Lipids Health Dis. 16, 95. Zielinska, M., Michalska, A., 2018. The influence of convective, microwave vacuum and microwave-assisted drying on blueberry pomace physicochemical properties. Int. J. Food Eng 14 (3), 20170332.

Further reading Rødtjer, A., Skibsted, L.H., Andersen, M.L., 2006. Antioxidative and prooxidative effects of extracts made from cherry liqueur pomace. Food Chem. 99, 6
14.

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Chapter 6

Chestnut Diana Pinto1, Nair Braga1, Ana Margarida Silva1, Paulo Costa2, Cristina Delerue-Matos2 and Francisca Rodrigues1 1

REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto, Instituto Polite´cnico do Porto, Porto, Portugal, 2REQUIMTE/UCIBIO, Department

of Drug Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal

Chapter Outline 6.1 Introduction 6.2 Castanea sativa by-products 6.2.1 Leaves 6.2.2 Flowers 6.2.3 Shells

128 128 129 133 135

6.2.4 Burs 6.3 Future perspectives 6.4 Conclusion Acknowledgments References

137 140 140 141 141

Abbreviations CBMN BHA CEQ DNA DPPH DW EC50 FAO FW GAE HPLC IC50 MBC MIC PUFAs RH RNS ROS SFAs STZ TPC TE TEWL TFC UV

cytokinesis-block micronucleus Butylated hydroxyanisole catechin equivalents deoxyribonucleic acid 2,2-diphenyl-1-picrylhydrazyl dry weight half maximal effective concentration Food and Agriculture Organization of the United Nations fresh weight gallic acid equivalents high-performance liquid chromatography half maximal inhibitory concentration minimum bactericidal concentration minimum inhibitory concentration polyunsaturated fatty acids relative humidity reactive nitrogen species reactive oxygen species saturated fatty acids streptozotocin total phenolic content Trolox equivalents transepidermal water loss total flavonoid content ultraviolet

Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00006-X © 2020 Elsevier Inc. All rights reserved.

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6.1

Introduction

Castanea sativa Mill. is a species of the Fagaceae family that can be found in south Europe and Asia (China). The fruit, chestnut, is extremely appreciated all over the world, being a seasonal nut (autumn) in the Mediterranean countries (Cruz et al., 2013). The European or sweet chestnut (C. sativa Mill.) is an important tree species, with an invaluable historical and cultural heritage, that plays an important role in the economic and environmental context of mountain areas. Across the world’s regions other species are predominant: Castanea crenata Sieb. and Zucc. is widely disseminated in Japan, while Castanea mollissima Bl. is present in China and Korea, and Castanea dentata Borkh in North America. According to Food and Agriculture Organization of the United Nations (FAO) data, the production of chestnuts has been increasing since 2001, from about 691,279 K in 2001 to 2,327,495 K in 2017 (FAO, 2019). Asia is the major chestnut producer (87.1%), followed by Europe (9.1%) and America (3.8%) (FAO, 2019). In 2017 China was the country with the largest volume of chestnut output (1095 thousand tonnes), accounting for 83% of global production, followed by the Republic of Korea, Turkey, Italy, and Bolivia (FAO, 2019). Portugal, Spain, and Greece are also in the top 10 producers (FAO, 2019). The chestnut tree has a variety of applications. The nuts are used for human and animal feed, being widely appreciated and even transformed into many typical dishes and desserts, while the wood is used for high class furniture. Chestnut is composed by the fruit, pericarp (outer shell), integument (inner shell), and bur that surrounds the edible nuts (Braga et al., 2015). From a nutritional point of view, chestnut fruits can be used as an important source of dietary energy, due to their starch, carbohydrates, and low fat content (de Vasconcelos et al., 2010; Barreira et al., 2012). New applications for chestnuts are being explored. An example is the significant importance of chestnut fruits in celiac disease due to their gluten-free properties, ameliorating the response of the body’s immune system to gluten proteins (Demirkesen et al., 2010). Actually it is easy to find new products in the market that are gluten-free, such as breads made from chestnut flour (Demirkesen et al., 2010). Nevertheless, during fruit processing, different by-products are generated, namely leaves, shells, and burs, which are still a valuable source of bioactive molecules (Braga et al., 2015). According to different authors, the bioactive compounds determined are associated with health benefits, such as antioxidant, anticarcinogenic and cardioprotective properties (Barreira et al., 2008; Squillaci et al., 2018). In addition, in some cases, flowers could be considered a by-product. The concepts of sustainability and circular economy gained attention in the last decade,particularly from food industries, governments, and consumers. According to the new policies developed by the European Commission (EU), the main goal for sustainable development is to achieve “a continuous long-term improvement of quality of life through the creation of sustainable communities able to manage and use resources efficiently, (. . .) to tap the ecological and social innovation potential of the economy and (. . .) to ensure prosperity, environmental protection and social cohesion” (EU, 2017). In this way the chestnut industry can be part of the sustainable and circular economy. Taking into consideration the Sustainable Development Goals of 2030 Agenda, chestnut production and by-products processing perfectly fit in almost all of these new goals (Nations, 2018). On the other hand, since it is a product spread all over the world it is expected a huge impact on different economies in the future. From a sustainable point of view, these chestnut by-products could provide a way to recycle for chestnut-processing companies, developing cost-efficient processing methods, decreasing the negative impacts of wastes on the environment, and providing other economical advantages. Three main goals have been established as policies for the EU: “more value
less impact
better alternatives” (Behrens et al., 2007). The reutilization impact of these wastes as valuable products leads to benefits for the environment, pollution costs, and economy at a world level (Lang et al., 2007). Chestnut worldwide production can provide the conservation and management of all natural resources (fruit, wood, and by-products) with health and social benefits for the population and economic benefits for several industries that directly or indirectly can be part of the process. After valorization these agroindustrial wastes can be used by other industries, such as pharmaceuticals, food, or cosmetics, generating more profits, reducing pollution costs, and improving social, economic, and environmental sustainability (Braga et al., 2015). The aim of this chapter is to revise the biochemical composition and the potential sustainable use of chestnut by-products. A particular emphasis is given to each by-product, namely leaves, flowers, shells, and burs. The challenge is to recover bioactive compounds from chestnut by-products, in order to valorize the chestnut-processed materials, and simultaneously place them on the verge of commercialization.

6.2

Castanea sativa by-products

Fig. 6.1 summarizes the different by-products of chestnut processing.

Chestnut Chapter | 6

129

FIGURE 6.1 Chestnut by-products.

6.2.1

Leaves

C. sativa leaves are used in folk medicine for the treatment of several diseases such as bronchitis, cough, diarrhea, rheumatic conditions, lower back pain, and stiff joints or muscles (Almeida et al., 2008a; Dı´az Reinoso et al., 2012). Nowadays topical natural antioxidants have been described as useful ingredients in the prevention of photoaging and oxidative stress-mediated skin diseases. The skin exposure to ultraviolet (UV) radiation initiates an imbalance between the generation of prooxidant reactive species [such as reactive oxygen species (ROS) and reactive nitrogen species (RNS)] and the antioxidant defense capacity of cells (including enzymes, such as catalase and superoxide dismutase, and nonenzymatic antioxidants, namely ascorbic acid, glutathione, and α-tocopherol), resulting in oxidative stress. ROS can react with various cellular components, including cell walls, lipid membranes, mitochondria, and deoxyribonucleic acid (DNA), inducing skin damage. On the other hand, RNS might interfere with cellular functionalities through DNA injuries, promoting lipid peroxidation and nitrosylation of tyrosine residues in proteins. UV radiation affords toxic effects on skin such as DNA damage and lipid and protein oxidation, presenting a key role in photoaging and photocarcinogenesis. In this sense, plants extracts with scavenging capacity against ROS and RNS may have an important function in the prevention of photoinduced oxidative stress in the skin (Almeida et al., 2008b). The growing evidence of the UV-mediated generation of ROS and RNS in skin supports the rationale for the inclusion of antioxidants in topical formulations. For instance, some of these natural extracts present considerable amounts of potent antioxidants such as polyphenols and vitamin C and E, which have been reported as effective in protecting skin against UV-mediated damage. Although isolated polyphenols can be used, they might be better employed as a set of components present in plant extracts with potential synergetic effects. In order to develop novel topical antioxidant formulations, the screening of natural plant extracts with a marked scavenging capacity for prooxidant reactive species is of great importance. For this reason, Calliste et al. analyzed aqueous, ethyl acetate, and methanolic extracts from chestnut leaves as a new source of natural antioxidants through an electronic spin resonance study. Regarding the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the ethyl acetate extract was the most effective (IC50 5 17 μg/mL). Likewise the ethyl acetate and the water fractions from the aqueous extract were the most active scavengers against superoxide anion radical (O2 2 ; IC50 5 1.6
1.9 μg/mL) and hydroxyl radical (HO ; IC50 5 160
310 μg/mL). Also the same ethyl acetate fraction presented the highest total phenolic content [TPC; 29.1 g/100 g dry weight (dw)]. Therefore, the concentration of the bioactive compounds of the ethyl acetate fraction in C. sativa leaf extract prepared as an infusion with distilled water: acetone (1:2) evidenced their high antioxidant potential comparing to reference antioxidants (such as quercetin and vitamin E) and standard extracts (pycnogenol, from French Pinus maritima bark, and grape marc extract) (Calliste et al., 2005). In 2008 Almeida et al. prepared an ethanol:water (7:3) extract from C. sativa leaves that displayed a high effectiveness to scavenge ROS and RNS (Almeida et al., 2008a). According to the authors the IC50 value for O2 2 was G

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13.6 μg/mL, for HO 216 μg/mL, for hydrogen peroxide (H2O2) 410 μg/mL, for singlet oxygen (1O2) 12.3 μg/mL, for nitric oxide (NO ) 3.10 μg/mL, for peroxynitrite (ONOO2) without NaHCO3 149 μg/mL, and for ONOO2 with NaHCO3 1.95 μg/mL. These results are similar or even better than the scavenging power of the controls and standards (Almeida et al., 2008a). The remarkable scavenging ability of chestnut leaves extract against O2 2 and hydroxyl radical (HO ) was attributed to the phenolic composition, as previously described by Calliste et al. (2005). Thus, the leaves extract exerted a more potent scavenging capacity against RNS than ROS. The scavenging ability of the extract against peroxyl radical (ROO ), through oxygen radical absorbance capacity assay, was 1.24 μmol of Trolox equivalents (TEs)/ mg dw, being similar to ascorbic acid (1.24 μmol TE/mg dw), while the TPC was 284 mg of gallic acid equivalents (GAEs)/g dw. In addition, chestnut leaves revealed a scavenging power similar to quercetin and its derivatives (Boeing et al., 2017; Almeida et al., 2018; Marangi et al., 2018). Thus Almeida et al. (2008a) proved the protective effect of C. sativa leaves extracts against ROS and RNS, highlighting their remarkable antioxidant activity (Almeida et al., 2008a). In another study, Almeida et al. studied the relationship between the antioxidant activity observed in C. sativa leaves and the phenolic composition (Almeida et al., 2008b). The extraction method optimized comprised five short extractions (10 min each) with ethanol:water (7:3) at 40 C, with the extraction efficiency being approximately 86%. This extract was also selected based on the highest TPC (283.8 mg GAE/g dw) and antioxidant activity (DPPH assay: IC50 5 12.58 6 0.54 μg/mL; iron chelation assay: IC50 5 132.94 6 9.72 μg/mL) among other aqueous and ethanolic extracts (Almeida et al., 2008b). Several phenolic compounds were identified, including phenolic acids (chlorogenic acid and ellagic acid) and flavonoids (hyperoside, isoquercitrin and rutin) (Almeida et al., 2008b, 2010) that have been described as good ROS and RNS scavengers (Foley et al., 1999; Zou et al., 2004; Aboul-Enein et al., 2007). The major phenolic compound detected was rutin, a compound with a preventive effect against photooxidative stress induced by UVA radiation and one of the less toxic flavonoids (Filipe et al., 2005; Matsuo et al., 2005; Almeida et al., 2008b). A strong absorption of this extract at 280 nm (UVB) evidences the potential effectiveness as a preventive agent of UV radiation-induced skin damage. In addition, an in vivo patch test in 20 volunteers demonstrated no irritant effects when analyzed 2 and 24 h after patch removal, concluding that the extract is safe for topical application. Therefore, this study proved a good skin tolerance for C. sativa leaves extract, highlighting its promising application in the cosmetic industry (Almeida et al., 2008b). In fact there are essential requirements for cosmetic and pharmaceutical applications of plants extracts, not only in terms of efficacy but also quality and safety (Almeida et al., 2008b). Almeida et al. evaluated the reproducibility of the extraction procedure and the functional stability of the extract in aqueous and glycerin solutions (0.025%, w/v) on three different batches for a 3-month period (Almeida et al., 2010). All the batches presented similar TPC, antioxidant activity (through DPPH assay), and extraction yield. Although the high-performance liquid chromatography (HPLC) chromatograms were similar for the three batches, some variations were found in the amounts of phenolic compounds that might be related to the plant extract complexity and method variability. Taking all these results together, the authors proved the reproducibility of the extraction method, yielding extracts with suitable quality with regards to TPC and antioxidant activity. Concerning pH, a major decrease on antioxidant activity was observed at 7.1. At 40 C and pH 5 a well-marked decrease on antioxidant activity was observed at day 7 with even higher decreases throughout the test period since the extract functional stability can be influenced by pH and temperature. Moreover, glycerin solutions with this extract were more stable than aqueous ones over the storage period. These differences might be explained by the beneficial role of glycerin in the polyphenols stability. Particularly, in a study with glycerin-based carbopol gel, epigallocatechin remained stable at 50 C (Proniuk and Blanchard, 2002). Also, glycerin has a well-known skin hydration effect and, at higher concentration, could reduce the transepidermal water loss (TEWL) (Loden and Wessman, 2001; Almeida et al., 2010). In conclusion, the storage at 4 C and pH 5 seems to protect these extracts from degradation as minor differences were detected in the IC50 values during 90 days. The overall outcomes suggested the preparation of formulations of C. sativa leaves extract containing glycerin and adjusting the pH to 5 (Almeida et al., 2010). According to the same authors, C. sativa leaves extract presented a concentration-dependent protective effect against UV-mediated DNA damage in keratinocytes (HaCaT) evaluated through cytokinesis-block micronucleus (CBMN) assay, with the maximum protection (66.4%) being afforded for the concentration of 0.1 μg/mL (Almeida et al., 2015a). The CBMN assay has emerged as a valuable tool to analyze the protective effects of potential cosmetic ingredients against genotoxic agents as well as characterizing their genotoxicity through the evaluation of chromosome loss and chromosome breakage. The photoprotective effect of C. sativa leaves extract can be attributed to the direct antioxidant effect involving singlet oxygen (1O2) since this ROS is generated in human skin after UVA exposure (Baier et al., 2007). More recently, other ROS (including O2 2 , HO , and ROO ) have been identified in skin after UV exposure (Masaki et al., 1995; Sakurai et al., 2005). The electrochemical studies suggested that the good antioxidant ability of the chestnut leaves extract (anodic wave at Ep 5 10.207 V) is probably related to the presence of different phenolic G

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compounds, such as rutin (Ep 5 10.215 V), chlorogenic acid (Ep 5 10.191 V), and ellagic acid (Ep 5 10.227 V) (Almeida et al., 2015a). Additionally, in concentrations up to 5 μg/mL this extract was considered as noncytotoxic for HaCaT cells since the cell viability was approximately 100%. Also no genotoxic or phototoxic effects were found in concentrations up to 0.1 μg/mL. The ability of this extract to protect HaCaT cells against UVA-induced DNA damage could be related to the presence of ellagic acid, which was one of the phenolic compounds identified in this extract (Almeida et al., 2008b; Hseu et al., 2012). Overall this paper highlighted a moderate to high antioxidant capacity and good skin compatibility, considering the application of this extract in skin care products (Almeida et al., 2008a,b, 2015b). For this reason Almeida et al. incorporated 0.5% of ethanol:water (7:3) chestnut leaves extract into a semisolid surfactant-free formulation (Almeida et al., 2015b). The formulation presented a rheofluidificant behavior (viscosity decreases with increasing shear stress) that is typical of water in oil emulsions. In a preliminary stability study no significant changes were found in pH, firmness, organoleptic features (after a vibrational test), and antioxidant activity (evaluated through thermal stress). Otherwise, in the long-term stability study, minor changes in the textural and rheological properties were detected at 20 C after 6 months of storage, while the pH (B4.7) and antioxidant activity (IC50 5 17.1
19.9 μg/mL) remained constant. After a 6-month period, no microbial contamination was detected at 20 C, proving the microbiological quality of formulations. Therefore physical, functional, and microbiological stability of the formulation was confirmed when stored at 20 C. However, after 6 months of storage at 40 C and 75% relative humidity (RH) considerable changes in the rheological properties were detected, with a decrease in consistency coefficient and firmness. The DPPH scavenging activity slightly decreased with time probably due to the thermal degradation of some antioxidant compounds. Comparing the results for C. sativa leaves extract and the formulation containing this extract, it was possible to conclude that the extract preserved its antioxidant activity and afforded a protection from thermal oxidation after incorporation in the semisolid base. The release rate of the antioxidant compounds from the formulation followed the Higuchi model (610 6 70 μgh20.5), comprising a delivery of antioxidants for a long period of time. In addition, this formulation showed a significant in vivo moisturizing effect that lasted at least 4 h after application and no effect on TEWL was observed, suggesting a good skin tolerance with no barrier disruption. Overall, this topical formulation might be used in the prevention or treatment of oxidative stress-mediated dysfunctions (Almeida et al., 2015b). According to different studies of Barreira et al. the water extracts of chestnut leaves showed the ability to promote the inhibition of β-carotene bleaching, lipid peroxidation, and hemolysis as well as a considerable reducing power (Barreira et al., 2008, 2010a). Barreira et al. (2010b) studied aqueous extracts of chestnut by-products from different cultivars and reported better results for skins and leaves, with the extraction yields being generally low (13.73%
17.67%). The TPC (228.37
522.98 mg GAE/g dw) and total flavonoid content (TFC) (73.31
90.39 mg CE/g dw) of C. sativa leaves were lower than the ones obtained for skins. Although skins showed higher antioxidant power, the leaves presented lower IC50 values (64.14
160.04 μg/mL) for β-carotene bleaching inhibition assay. Chestnut leaves from “Longal” cultivar had the highest TPC (522.98 mg GAE/g dw), TFC (90.39 mg CE/g dw), and antioxidant activity (β-carotene bleaching inhibition: IC50 5 64.14 μg/mL; thiobarbituric acid reactive substances (TBARS): IC50 5 69.04 μg/mL; DPPH: IC50 5 129.91 μg/mL; reducing power: IC50 5 152.38 μg/mL) (Barreira et al., 2010a). ˇ A study performed by Zivkovi´ c et al. reported that catkins, leaves, and spiny burs extracts from C. sativa showed 2 high antioxidant activity against O2 2 , but lower capacity against HO . The inhibition of O2 production decreased in the following order: spiny burs . leaves 5 catkins. The antioxidant activity of C. sativa extracts against O2 2 seems to be related to the content of ellagitannins derivatives. Moreover, the antioxidant capacity of extracts against HO followed the order: leaves . catkin 5 spiny burs and is possibly related to the flavonoids content. These chestnut extracts also presented a protective effect on the fluidity of erythrocytes membranes exposed to H2O2 based on the similarity between order parameter, as well as prevented changes in their integrity through the reduction on efflux of potassium, with catkins and leaves extracts being more efficient than spiny burs. Hydrolyzable tannins, namely ellagitannins and gallotannins, were also reported as the main phenolic compounds. In conclusion, through electron paramagnetic resonance techniques it was possible to observe that chestnut extracts were good scavengers for O2 2 and HO , as well as ˇ c et al., 2009). provide protection to cellular membranes from oxidative damage (Zivkovi´ In another study a response surface methodology was undertaken to determine the optimal extraction conditions, since the aqueous extract displayed the highest phenolic release and highest antioxidant activity (Dı´az Reinoso et al., 2012). An extraction time from 50 to 90 min and temperatures below 30 C were selected as the optimal extraction conditions. Although the methanolic extracts showed the highest extraction yields, aqueous extracts allowed a selective extraction (with phenolic yields up to 9 mg GAE/100 mg dw). Moreover, the main structural fraction in C. sativa leaves was lignin (37.2 g/100 g), followed by hemicelluloses (24.3 mg/100 g), xylose (9.41 g/100 g), and uronic acids (9.39 g/ G

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1 100 g). Aqueous extract from chestnut leaves showed a marked scavenging ability for O2 2 (IC50 5 15.1 μg/mL) and O2 (IC50 5 11.6 μg/mL), while a lower scavenging power was observed against H2O2 (32.3% at the highest tested concentration (50 μg/mL)) and hypochlorous acid (HClO; IC50 5 63.8 μg/mL) (Dı´az Reinoso et al., 2012). However, aqueous extract from C. sativa leaves was a better scavenger for the studied RNS (NO : IC50 5 7.15 μg/mL; ONOO2 without NaHCO3: IC50 5 1.56 μg/mL; ONOO2 with NaHCO3: IC50 5 3.24 μg/mL) than for ROS, as already reported by Almeida et al. (2008a) and Dı´az Reinoso et al. (2012). The major phenolic compounds identified in these extracts were gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid, rutin, quercetin, and apigenin (Dı´az Reinoso et al., 2012). Dı´az-Reinoso et al. (2011) proposed a scale-up for aqueous extract from C. sativa leaves by an environmentfriendly process coupled to two UF membranes (5 and 10 kDa) that proved to be suitable for the concentration and selective recovery of antioxidants (Dı´az-Reinoso et al., 2011). The precipitation of concentrates with ethanol increased their purity and the activity of the final products by about 15%. A high amount of phenolic compounds, particularly tannins, were concentrated in water fractions. The final concentrated extracts displayed radical scavenging activities comparable to butylated hydroxyanisole (BHA) and Trolox. Based on a high cell viability (83.74%) and a low IL-1α content (16.2 pg/mL), the aqueous extract from chestnut leaves was confirmed as a nonirritant at 1% through an assay with reconstituted human epidermis (Episkin), being classified as safe for topical use. Also, the use of membranes resulted in an increase of 18% in the TPC (Dı´az-Reinoso et al., 2011). In particular, pancreatic β-cells are responsible for the synthesis and secretion of insulin, being more vulnerable to oxidative stress than other cell types based on their low levels of enzymatic antioxidant defenses (Moussa, 2008). Therefore, the interest in plants extracts described as useful in the control of diabetes through hypoglycemic and antioxidant effects is growing as a result of their richness in phenolic compounds with the ability to inhibit ROS and inflammation processes (Calliste et al., 2005; Le Corre et al., 2005). Muji´c et al. (2011) studied the antioxidant effects of phenolic-rich chestnut extracts from leaves, catkins, and spiny burs in streptozotocin (STZ)-treated rat pancreatic β-cells (Rin-5F). A diabetogenic agent, STZ, was used to induce the Rin-5F cell death (final concentration of 5 mM caused 54.7% of cells death). Chestnut leaves showed a higher TPC (1.40 g GAE/100 g dw) and TFC (0.32 g CE/100 g dw) than spiny burs (TPC: 0.49 g GAE/100 g dw; TFC: 0.13 g CE/100 g dw), but lower than catkins (TPC: 3.28 g GAE/100 g dw; TFC: 0.60 g CE/100 g dw). Regarding DPPH assay the antioxidant activity increased in the following order: catkin . leaf . spiny burs. This study also proved that chestnut extracts increased the cell viability of STZinduced cells through the protection of DNA from oxidative damage with an increase of 17.7%, 9.9%, and 23.8% for catkin, leaf, and spiny burs, respectively. Chestnut extracts also attenuated the effects of oxidative stress in pancreatic β-cells, inhibiting the lipid peroxidation (with malondialdehyde levels in STZ/chestnut extracts-treated cells between 2.1 and 3 fold lower than in the STZ-treated cells) and enhancing the natural antioxidant system by reducing glutathione levels. In addition, 2.7-, 2.6-, and 1.9-fold increases on the activity of superoxide dismutase were detected for catkin, leaf, and spiny burs, respectively. Overall, after STZ treatment, the chestnut extracts increased cell viability based on their antioxidant properties and significantly lowered the risk of oxidative stress-induced cell death (Muji´c et al., 2011). In another study Basile et al. suggested a strong antibacterial activity against Gram-positive and Gram-negative bacteria (minimum inhibitory concentration (MIC): 64
256 μg/mL; minimum bactericidal concentration (MBC): 256
512 μg/mL) for the ethyl acetate soluble fraction of the chestnut leaves aqueous extracts, being this possible related to the content of flavonoids (Basile et al., 2000). A pronounced allelopathic activity against Raphanus sativus seed germination was also observed through a decrease in the percentage of seed germination and root and epicotyl growth (Basile et al., 2000). Recently, Zamuz et al. suggested the incorporation of chestnut extracts, preferably a mixture from different chestnut by-products such as bur, hull, and leaf, in beef patties stored under modified atmosphere packaging, emphasizing their potential as food ingredients based on the preservation of sensorial properties of the beef patties and improved shelf life. The natural antioxidants present in these extracts can substitute the synthetic ones (Zamuz et al., 2018). Even though the natural products can cause adverse skin effects such as allergic and irritant contact dermatitis, the topical use of natural antioxidants has proven to be effective in skin protection against UV-mediated oxidative damage and reinforces the endogenous antioxidant protection system. Thus, antioxidants from natural products have been described as novel possibilities for the treatment and prevention of oxidative stress-mediated skin diseases. This agroresidue is a biorenewable material extensively used in traditional medicine and with huge availability. Overall C. sativa leaves have been described as a promising raw material for food, pharmaceutical, and cosmetic industries and a good source of bioactive compounds responsible for noteworthy biological activities, namely scavenging capacity against ROS and RNS (Calliste et al., 2005; Almeida et al., 2008a), antioxidant activity (Almeida et al., 2008b, 2015b), interesting phenolic profile (Calliste et al., 2005; Almeida et al., 2008b), as well as stability (Almeida et al., 2010, 2015b) and skin compatibility (Almeida et al., 2008b, 2015a). G

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6.2.2

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Flowers

Flowers from semiwild and wild species, such as C. sativa, have been traditionally used for several folk medicinal applications (Barros et al., 2013). Chestnut flowers, also known as catkins, are by-products of the nut harvesting with no use, except being fertilizer. Although chestnut fruit is a good source of antioxidant compounds, flowers are richer polyphenolic matrices presenting some of the most antioxidant molecules that are not always found in fruits. Several studies have proven the antioxidant and antimicrobial potential of C. sativa flowers as raw matrix (Barros et al., 2010, 2013; Carocho et al., 2014b,c). The consumption of C. sativa flowers has been related to beneficial outcomes toward health (Barros et al., 2010, 2013; Carocho et al., 2014b,c). Therefore some of the ancient claims based on the benefits of the consumption of chestnut flowers infusions and decoctions have been recently related to their antioxidant, antitumor, and antimicrobial effects (Carocho et al., 2014b,c). Although these flowers have a large range of benefits, they should not be harvested from the tree, but preferably be picked up from the ground to avoid interference with pollination (Barros et al., 2010). In folk medicine herbal and plant infusions are frequently used based on their antioxidant and pharmacological properties linked to the presence of phenolic compounds (Le Marchand, 2002; Dawidowicz et al., 2006). Folk medicine and traditional healing practices simultaneously coexist with institutionalized medicine systems in rural areas (Barros et al., 2010). A study conducted by Barros et al. revealed the interesting in vitro antioxidant properties, as well as nutrients and phytochemical composition, of six medicinal plants (including C. sativa flowers) widely used in the northeastern Portuguese region, finding correlations with their folk medicinal uses (Barros et al., 2010). The methanolic extracts of C. sativa flowers displayed higher DPPH scavenging capacity (IC50 5 0.07 mg/mL), reducing power (IC50 5 0.07 mg/ mL), β-carotene bleaching inhibition (IC50 5 0.11 mg/mL), and TBARS inhibition (IC50 5 0.03 mg/mL) than five samples also analyzed in this study. These values were only lower than the ones obtained for Rubus ulmifolius (Barros et al., 2010). In addition, these results were lower than the ones reported by Barreira et al. for chestnut flowers aqueous extract (DPPH: IC50 5 0.08 mg/mL; reducing power: IC50 5 0.09 mg/mL; β-carotene bleaching inhibition: IC50 5 0.16 mg/mL), except for TBARS inhibition that had a lower value (IC50 5 0.01 mg/mL) (Barreira et al., 2008; Barros et al., 2010). The same conclusion was observed for TPC and TFC since Barreira et al. obtained lower values (TPC: 298.18 mg GAE/g extract; TFC: 159.56 mg CE/g extract) than the ones reported in this study (TPC: 587.61 mg GAE/g extract; TFC: 165.45 mg CE/g extract) (Barreira et al., 2008). These differences prove that the solvent used for extraction has a significant influence on the TPC, TFC, and antioxidant activity. Moreover, the variety of chemical composition and biological activities of medicinal plants depend on various factors, such as climatic conditions, genetic changes, growth habitat, and vegetation phase (Miliauskas et al., 2004). Also Barros et al. demonstrated that methanolic extracts from chestnut flowers displayed the highest amount of phenolic compounds [18,973 μg/g fresh weight (fw)] and hydrolyzable tannins (14,873 μg/g fw) among other medicinal plants (Barros et al., 2013). Hydrolyzable tannins (e.g., tri and digalloyl hexahydroxydiphenic acid (HHDP) glucose) was the main group of phenolic compounds reported in C. sativa flowers (Barros et al., 2013). In these two studies Barros et al. obtained similar extraction yields for methanolic extracts prepared from chestnut flowers (38%) (Barros et al., 2010, 2013). However, the use of methanol in food industry is not recommended since this is not a green solvent. On the other hand, extractions performed with this solvent might recover hydrophobic antioxidant compounds. Similarly to Filipendula ulmaria and Rosa micrantha, the methanolic extracts of chestnut flowers presented a promising antifungal activity against four Candida species (C. albicans, C. glabrata, C. parapsilosis, and C. tropicalis), revealing a fungistatic effect even at the highest concentrations tested for all fungi studied (Barros et al., 2013). Regarding the vitamin E profile, C. sativa flowers presented the highest content of tocopherols (163.42 mg/100 g dw) with the highest levels of all isoforms (α-, β-, δ-, and γ-tocopherols), being α-tocopherol the major compound (124.64 mg/100 g dw) (Barros et al., 2010). Ascorbic acid was the most abundant vitamin in all studied medicinal plants with 163.48 mg/100 g dw for C. sativa flowers, whereas carotenoids (β-carotene: 43.53 mg/100 g dw; lycopene: 0.05 mg/100 g dw) and chlorophylls (chlorophyll a: 1.06 mg/100 g dw; chlorophyll b: 0.46 mg/100 g dw) were also found in these flowers (Barros et al., 2010). The considerable levels of vitamins C and E, polyphenols, and carotenoid pigments present in medicinal plants contribute to their use as suitable sources of antioxidants that could be employed commercially in food manufacturing to retard rancidity in fatty products, protect against lipid oxidation, reduce the aging effects, and prevent oxidative stress-related diseases (Dewick, 2002). With regards to sugars, chestnut flowers showed the highest content (11.91 g/100 g dw), with fructose (5.05 g/100 g dw) and glucose (4.62 g/100 g dw) as main sugars. Some of the identified sugars, mainly the reducing sugars fructose, glucose, and raffinose, might contribute to the antioxidant activity of these plants (Barros et al., 2010). Twenty-one fatty acids were identified and quantified in chestnut flowers with α-linolenic acid (C18:3n3) (21.24%) and linoleic acid (C18:2n6) (20.88%) being the major ones.

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The high amounts of palmitic acid (C16:0), arachidic acid (C20:0), and behenic acid (C22:0) contribute to the prevalence of saturated fatty acids (SFAs) in this sample (51%) (Barros et al., 2010). The presence of α-linolenic and linoleic acids, high ratios of polyunsaturated fatty acids (PUFAs)/SFAs ( . 0.45), and low n 2 6/n 2 3 fatty acids ratios (,4.0) can decrease the total fat content in blood (cholesterol) and reduce the risk of cancer and autoimmune, cardiovascular, and inflammatory diseases (Kanu et al., 2007). In order to preserve the ancestral knowledge and the local traditional medicine Neves et al. performed an ethnopharmacological study on medicinal plants from Tra´s-os-Montes (a northern region of Portugal), demonstrating that the most frequently used part of the plants were leaves (37.9%), closely followed by flowers (34.7%) (Neves et al., 2009). The main preparation modes were infusions or decoctions of leaves, aerial parts, and flowers. C. sativa leaves, flowers, and bark macerated are popularly used for the “treatment” of cough (in children), diarrhea, and infertility, while their therapeutic properties focused on antidysenteric, antispasmodic, and mucolytic effects (Neves et al., 2009). Infusions and decoctions of C. sativa flowers have been studied to provide scientific evidence to the ancestral claims regarding their consumption. With regards to phenolic profile, antioxidant activity, and organic acids composition, Carocho et al. (2014b) concluded that the infusions were quite poor compared to the decoctions. In this study three free sugars were reported in C. sativa flowers decoctions and infusions from “Judia” and “Longal” cultivars, namely fructose, glucose, and sucrose. Fructose and glucose were the most abundant free sugars in both cultivars with higher levels in decoctions (fructose: 152.08
160.41 mg/g; glucose: 149.09
191.91 mg/g) than in infusions (fructose: 123.58
148.94 mg/g; glucose: 145.71
164.07 mg/g) probably due to the longer extraction time. However, infusions showed higher amounts of sucrose (26.67
35.68 mg/g) than decoctions (25.69
27.01 mg/g) (Carocho et al., 2014b). Regarding organic acids, quinic acid was the most abundant followed by oxalic, malic, and shikimic acids, except for a decoction from the “Longal” cultivar that had a higher level of oxalic acid. The decoction from “Judia” cultivar displayed the highest amount of total organic acids (186.52 mg/g) (Carocho et al., 2014b). Organic acids are another type of antioxidant molecules with beneficial effects, such as the scavenging activity against free radicals (Barros et al., 2010; Pereira et al., 2013). Thus some antioxidant power could be attributed to the organic acids. For all samples, 27 phenolic compounds were identified. The main polyphenols present in decoctions and infusions from C. sativa flowers were trigalloyl-HHDP-glucoside and pentagalloyl glucose, while quercetin 3-O-glucuronide and quercetin hexoside were the prevailing flavonoids in “Judia” and “Longal” cultivars, respectively (Carocho et al., 2014b). The highest TPC was found in the infusion of “Judia” (72.20 mg/g) followed by the decoction of “Longal” cultivar (69.88 mg/g), whereas the higher TFC was determined for infusions (12.94 mg/g) and decoctions (14.26 mg/g) of “Judia” cultivar. Concerning the hydrolyzable tannins, the preparations of “Longal” cultivar showed higher levels (decoction: 61.49 mg/g; infusion: 60.32 mg/g) than those of “Judia”. In terms of antioxidant activity, decoctions displayed a greater antioxidant activity (DPPH: IC50 5 99.47
100.04 mg/g; reducing power: IC50 5 68.51
76.07 mg/g; β-carotene bleaching inhibition: IC50 5 47.89
184.92 mg/g) than infusions (DPPH: IC50 5 126.61
133.56 mg/g; reducing power: IC50 5 90.65
98.79 mg/g; β-carotene bleaching inhibition: IC50 5 177.23
195.10 mg/g) possibly due to the longer extraction time at boiling point for decoctions. However, infusions had lower IC50 values (15.24
19.79 mg/g) for TBARS assay that could be related to the low heat resistance of antioxidants responsible for the inhibition of lipid peroxidation, such as tocopherols and other vitamins. Among the samples analyzed, a decoction of “Judia” cultivar was the most antioxidant (Carocho et al., 2014b). The differences between cultivars could be clarified based on the antioxidant variability of cultivars. In addition, infusions and decoctions of C. sativa flowers proved to be powerful antioxidants compared with other herbal matrices (Barros et al., 2010, 2013). The antitumoral and antimicrobial potential of chestnut flowers was also studied by Carocho et al. (2014c) including “Judia” and “Longal” cultivars extracted through infusions and decoctions. Relative to the nontumor liver primary culture (PLP2), the extracts showed no toxicity (GI50 . 500 μg/mL) which confirmed the safety of the consumption of flowers. The human tumor cell lines of breast (MCF7), colon (HCT15), cervical (HeLa), and liver (HepG2) carcinoma were used for the primary antitumor screening. Regarding antitumoral activity, the most sensitive cell lines were HepG2 and HCT15. In particular, “Longal” cultivar showed higher activity for HepG2 (infusion: GI50 5 266.01 μg/mL; decoction: GI50 5 278.09 μg/mL) while “Judia” cultivar was more active for HCT15 (infusion: GI50 5 276.84 μg/mL; decoction: GI50 5 259.85 μg/mL). For HeLa cells, no effect was observed at the highest concentration tested (GI50 . 500 μg/mL), whereas the same effect was detected for all the samples toward MCF7 cells (GI50 5 287.95 2 293.14 μg/mL) (Carocho et al., 2014c). The in vitro antitumoral activity of C. sativa flowers could be related to the presence of polyphenols, mainly trigalloyl-HHDP-glucoside and pentagalloyl glucoside (Carocho et al., 2014b). In fact pentagalloyl glucoside, which belongs to the ellagitannins family, has been described as an effective antitumoral agent (Zhang et al., 2009). With regards to antibacterial activity, decoctions had better results (with the eight lowest MIC values) toward different Gram-positive and Gram-negative bacteria, whereas infusions (mainly of

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“Longal” cultivar) had more effective antifungal activity (Carocho et al., 2014c). The better antibacterial effects for decoctions is probably related to the higher amount of trigalloyl-HHDP-glucoside and quercetin-3-O-glucuronide, as well as the higher content of organic acids and antioxidant activity (Carocho et al., 2014b). Otherwise the higher antifungal activity of infusions might be explained by a higher sensitivity of fungicidal compounds to heat extraction, since heating time for infusions were less than for decoctions (Carocho et al., 2014c). The antimicrobial properties provide a potential applicability of C. sativa flowers as natural antimicrobials in the food processing chain (Carocho et al., 2014c). The promising results obtained for methanolic and aqueous extracts of C. sativa flowers, as well as for their decoctions and dried flowers, justify the selection of these flowers to functionalize foods (Barreira et al., 2008; Barros et al., 2010, 2013; Carocho et al., 2014b,c). Besides the chestnut honey produced from flowers, another potential application is the incorporation of chestnut flowers and their decoctions in Portuguese traditional pastry with satiating qualities (Alissandrakis et al., 2011; Carocho et al., 2014a, 2015). Therefore these flowers were described as functionalizing ingredients with the ability to enhance the nutritional and antioxidant properties of highly appreciated traditional pastry (Carocho et al., 2014a, 2015). For instance, decoctions of chestnut flowers and dried flowers were added to Portuguese traditional cakes (Carocho et al., 2014a, 2015). Compared with the control, the functionalized cakes presented higher TPC and antioxidant activity. The samples functionalized with decoctions obtained results slightly higher than the ones reported for dried flowers. After a storage time of 15 and 30 days, it was possible to observe changes in the antioxidant ability (Carocho, 2014a). With regards to nutritional properties, Carocho et al. also described some variations with storage time (Carocho et al., 2015). The water content decreased (0 days: 14.3
18.7 g/100 g fw; 15 days: 14.7
18.0 g/100 g fw; 30 days: 11.0
13.0 g/100 g fw) in all samples. After 30 days of storage the cakes functionalized with decoctions showed higher contents of ash and carbohydrates, higher energy values, and lower protein levels, while a high insoluble fiber level was observed for cakes functionalized with dried flowers and decoctions. The organic acids (oxalic, quinic, malic, citric, succinic, and fumaric acids) were present in low quantities, with succinic acid being the most abundant. Fructose, glucose, and sucrose were the only three free sugars detected, with a high prevalence of sucrose. With regards to minerals composition, Ca, Mg, Na, and K were the macroelements found, whereas the microelements detected were Fe and Zn. The main fatty acids were palmitic acid (C16:0), stearic acid (C18:0), linoleic acid (C18:1n9c), linoleic acid (C18:2n6c), and linolenic acid (C18:3n3) in a total of 23 fatty acids detected. The amount of PUFA tended to decrease along storage since these fatty acids have a higher propensity to oxidation. Regarding vitamin E profile, α-, β-, and γ-tocopherol were detected, with α-tocopherol being the most prevalent (Carocho et al., 2015). According to Carocho et al., the incorporation of C. sativa dried flowers and respective decoctions are an advantageous practical application, as consumers might benefit from the bioactive compounds present in these natural ingredients and their antioxidant activity, without compromising the organoleptic qualities, as well as aiding the chemical and nutritional profiles of this appreciated pastry (Carocho et al., 2014a, 2015). Moreover, some patents refer to the use of chestnut flowers in beverages such as teas and refreshments (Patent CN102334573 B; Patent CN102524895 B). Additionally, the reuse of chestnut flowers might boost the local agriculture by increasing the demand for these discarded by-products. Based on the phytochemical profile and antioxidant potential, chestnut flowers could be interesting for use in the food industry through adding antioxidant extracts to foodstuffs or using them in coatings (Day et al., 2009). The potentialities of these flowers for pharmaceutical and food industries might be a promising field of research. Indeed pharmaceutical industries could use this by-product as excipients for dietary supplements and take advantage of their natural content in polyphenols for health purposes. On the other hand, food industries that are looking for new and natural preservatives and additives might use them to add to and transform foodstuffs, exploiting the high antioxidant potential and natural abundance of tannins in these flowers to preserve food, inhibit lipid deterioration, and prevent the development of microorganisms. Overall, the results of all these studies on chestnut flowers supporting their use for health purposes, and provide some basis to the folk recommendations.

6.2.3

Shells

Shells are another chestnut agroresidue with a huge potential to be reused and valorized. Different studies have been performed with this by-product in order to improve their value and application in different fields (Ozcimen and ErsoyMericboyu, 2009; Va´zquez et al., 2009a,b, 2012; de Vasconcelos, 2010; Rodrigues, 2015b). In the last decade a variety of studies have reported the richness of chestnut shells extracts in phenolic compounds, mainly phenolic acids and tannins (condensed and hydrolyzable) (Va´zquez et al., 2009b; de Vasconcelos, 2010; Rodrigues et al., 2015b). As an example, in 2008 Barreira et al. employed different biochemical assays to analyze the antioxidant properties of chestnut (flowers, leaves, skins, and fruits) extracts (Barreira et al., 2008). According to the authors, chestnut skins revealed the

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best antioxidant properties, presenting a proximate EC50 of 40 μg/mL. Furthermore, the highest antioxidant contents (polyphenols and flavonoids) were found for chestnut skins. The solvent employed by the authors for the extractions was water at boiling point. In 2010 the same authors reported a very low EC50 value (,380 μg/mL), particularly for lipid peroxidation inhibition (,140 μg/mL), for this chestnut by-product. The total phenols were also higher than 500 mg/g db sample and a good radical-scavenging activity was reported (Barreira et al., 2008, 2010b). Va´zquez et al. (2009b) also evaluated the phenolic content of chestnut shell extracts. The authors employed organic and aqueous solvents for the extraction, obtaining high yields and antioxidant activities with aqueous sodium sulfite and a mixture of sodium hydroxide and aqueous sodium sulfite at 90 C. The phenol content ranged between 13.4 and 188.4 g GAE/100 g extract for 2.5% aqueous sulfite hydroxide and sodium sulfite and sodium hydroxide (2.5%) at 90 C, respectively. The authors concluded that the solvent polarity and temperature clearly improved the extraction yields. In 2010 de Vasconcelos et al. also reported a good total phenolic for chestnut outer and inner shells, using different solvents (namely acetone, methanol, ethanol, and water), with the most efficient extraction solvent for the total phenolics, total condensed tannins, and low molecular weight phenolics being a mixture of acetone:water (70:30) at 20 C (de Vasconcelos et al., 2010). Ham et al. (2015) extracted the phenolic compounds from chestnut inner shell using aqueous alcohols and alkaline solutions (50% ethanol, 50% methanol, 1% NaOH, and 2% NaOH) at different temperatures (25 C 2 90 C). The phenolic composition, antioxidant activity, and deodorizing activity of the extracts were evaluated. According to the authors, the TPC and antioxidant activity were increased as the extraction temperature increased, with the hidroalcoholic (50%, v/w) being the most effective solvent to extract the total phenolics (558.12 mg GAE/g db sample) and resulting in the highest DPPH radical scavenging activity (174.61 mM TEs). Also Squillaci et al. evaluated a blend of inner and outer chestnut shells extracted through an ecofriendly method, and reported a high content (205.99 mg of GAE/g db), with gallic acid being the most abundant compound among those identified by HPLC (63.51 mg/g db) (Squillaci et al., 2018). The extracts also presented a protective activity against inflammation, decreased the nitric oxide and inducible nitric oxide synthase production, as well as offered protection against collagen degradation in HaCaT keratinocytes. This richness in antioxidants was also reported by Rodrigues et al. (2015b). These authors evaluated not only the antioxidant activity but also the macronutrient composition, the amino acid, and vitamin E profiles of C. sativa shells from different production regions of Portugal (Minho, Tra´s-os-Montes, and Beira-Alta). The antimicrobial activity of the different extracts was also reported. According to the authors, chestnut shells presented high moisture content and low fat amounts. Arginine and leucine were the predominant essential amino acids accounting for 3.55% 2 7.21% and 1.59% 2 2.08%, respectively. The predominant vitamer was γ-tocopherol (670 mg/100 g sample for Tra´s-os-Montes). The TPC varied from 241.9 mg to 796.8 mg GAE/g db sample, while the TFC ranged between 31.4 and 43.3 mg catechin equivalents (CEQ)/g db sample. No antimicrobial activity was observed. Recently, Gullo´n et al. (2018) used a hydrothermal treatment to solubilize hemicellulosic oligosaccharides from chestnut shells for potential use as prebiotics. The authors obtained the highest content of oligosaccharides (18.3 g/L) and a low level of monosaccharides (2.4 g/L) and degradation products (0.5 g/L) at 180 C. The GC
MS revealed that the most abundant phenolic compound was pyrogallol (13.2%). Taking into consideration the richness of chestnut shells in antioxidants compounds, a possible application in the field of cosmetics is of huge interest. For example, antioxidant activity is involved in the prevention of skin aging. The oxidative stress induced by UV radiation promotes skin injury and melanogenesis, releasing cytokines such as endothelin-1 and R-melanocyte-stimulating hormone from keratinocytes or melanocytes (Nunes et al., 2017). On the other hand, ROS are involved in skin UV-induced pigmentation. When in excess, ROS have deleterious effects, such as lipid and protein oxidation, DNA strand breakage, and modulation of gene expression (Esteve et al., 2015). The antioxidant compounds can act by preventing the melanogenesis process through the improvement of the skin’s oxidative stress defense (Rizza et al., 2012). Nevertheless, to the best of our knowledge, until now no studies have reported their incorporation in a final formulation. Further studies are needed to explore this application. With regards to its potential use as an adsorbent for heavy metals (e.g., for copper, lead, zinc, or cadmium) commonly found in industrial effluents, different authors have reviewed the shells’ potentials (Demirbas, 2008; O’Connell et al., 2008; Bilal et al., 2013). Biosorption is a recent alternative technology to remove and/or recover toxic metals from wastewater employing inexpensive biosorbent materials with high levels of effectiveness (Demirbas, 2008). When compared to the existing conventional technologies, this technology has also other advantages such as its high efficiency, low cost, regeneration of biosorbents, and possibility of metal recovery (Braga et al., 2015). In 2009 Va´zquez et al. (2009a) reported the great potential of chestnut shells as heavy metal adsorbents. According to the authors, Pb21, Cu21, and Zn21 can be removed from an aqueous solution using acidic formaldehyde pretreated chestnut shell as an adsorbent. The effectiveness is dependent on the initial cation concentration, the temperature, and the pH (Va´zquez et al., 2009a).

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The authors stated that carboxyl, carbonyl, amino, and alcoholic groups are involved in the metal uptake. In another study, Ozcimen and Ersoy-Meric¸boyu prepared activated carbon from chestnut shells to adsorbe copper ions from aqueous solutions, reporting that an increase in temperature, pH, and surface area leads to an increase in the adsorbent efficiency of the chestnut shell due to its high surface area and porosity (Ozcimen and Ersoy-Mericboyu, 2009).

6.2.4

Burs

Chestnut bur is a forest waste by-product that results from chestnut processing, representing about 20% of the total weight of this crop. After the fruit harvesting, this agroresidue generally remains in the woodland and could damage the crops due to the proliferation of insect larvae (Va´zquez et al., 2012). This chestnut by-product is a good source of fiber and polyphenols with remarkable antioxidant properties, being able to protect living tissues against oxidative stressrelated diseases, such as cardiovascular and neurodegenerative diseases, as well as photoaging (Barrera, 2012; Balboa et al., 2014). According to various authors, chestnut bur is a lignocellulosic waste rich in natural antioxidants (Conde et al., 2011; Va´zquez et al., 2012; Moure et al., 2014; Pinto et al., 2017b). Previous studies have demonstrated the potential of C. sativa bur as a cosmetic, nutraceutical, and food ingredient (Va´zquez et al., 2012; Pinto et al., 2017a,b). The nutritional composition of C. sativa bur is of great importance for the possible valorization of this agroresidue as a nutraceutical and cosmetic ingredient. Pinto et al. reported similar macronutrient profiles in C. sativa bur from three different Portuguese regions (Minho, Tra´s-os-Montes, and Beira-Alta), highlighting a high moisture content (15.5% 2 26.9%) and a low fat amount (0.85% 2 1.59%) (Pinto et al., 2017b). The ash content ranged between 1.37% and 5.61%, while the protein was between 2.22% and 3.16%. Carbohydrates were the major group of macronutrients (B60% 2 80%), comprising the nondigestible (namely lignins, pectins, or resistant starch) and indigestible components (dietary fiber fraction). Therefore the technological properties described by fiber fractions (such as water binding, gelling, and structure building capacities) linked to a high carbohydrates content can provide compositional advantages for this food by-product (Pinto et al., 2017b). Compared with the results reported by Moure et al. for ground chestnut bur, similar protein (4.2%) and ash (3.1%) contents were determined, but the moisture amount was lower (B10%) (Moure et al., 2014). In the proximate composition of chestnut bur was also detected 25.2% of glucan, 15.8% of xylan, 4.5% of arabinan, 1.80% of acetyl groups, and 24.2% of Klason lignin (Moure et al., 2014). In addition, the total dietary fiber content (70.8%) was in the same range as other dietary fiber-rich products such as fruits and vegetables (Elleuch et al., 2011) and roasted coffee silverskin (Borrelli et al., 2004). The ethanol-precipitated fiber obtained from chestnut burs through autohydrolysis at 120 C presented a considerable amount of neutral sugars (11.9 2 45.2 g/100 g) and phenolic compounds (22.8 2 41.9 g GAE/100 g), followed by ash (4.4 2 29.8 g/100 g) and uronic acids (6.80 2 18.8 g/100 g) (Moure et al., 2014). These compositional data suggest the potential application of the ethanol-precipitated solubilized fraction as dietary antioxidant fiber. The phenolic contents were similar or higher than the results reported for bran products (Zhao et al., 2005) and fenugreek seed husks (Madhava Naidu et al., 2011). The soluble fiber yield (6.19% 2 8.84%) was in the same range as the value found in coffee silverskin (8.8%) (Borrelli et al., 2004), highlighting the possible use in the supplementation of different foodstuffs and for the balance of fiber products with a high portion of insoluble fiber. Thus chestnut bur could be a useful source of antioxidant and fibers for food and pharmaceutical industries (Moure et al., 2014). The chemical composition of burs might be influenced by several factors, including cultivar, environment, and growth conditions. Pinto et al. observed significant differences (P , .05) between the amino acid profiles of burs from different production regions (Pinto et al., 2017b). In fact the essential amino acids were the main contributors for the protein fraction (57.86%
63.28%) in all bur samples, with arginine and leucine being the predominant essential amino acids. Glutamic and aspartic acid followed by proline were the most representative nonessential amino acids (Pinto et al., 2017b). Vitamin E is the major lipid-soluble antioxidant in the cell antioxidant defense system, being considered an essential nutrient that only can be provided from the diet. This vitamin is comprises eight chemical forms, including four tocopherols (α-, β-, γ-, and δ-) and four tocotrienols (α-, β-, γ-, and δ-) (Hasanuzzaman et al., 2014). Pinto et al. reported a substantially high amount of vitamin E for burs from Tra´s-os-Montes when compared with Minho and Beira-Alta, emphasizing that δ-tocopherol was the most representative vitamer in Tra´s-os-Montes samples, while α-tocopherol was the prevalent in Minho and Beira-Alta burs (Pinto et al., 2017b). Thus the vitamin E profiles of burs can be influenced by geographical origin (Pinto et al., 2017b). C. sativa bur presented a vitamin E profile slightly different from chestnut (Zlatanov et al., 2013) and shell (Barreira et al., 2009) for which γ-tocopherol was the main vitamer (representing more than half of the total amount).

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Polyphenols content and antioxidant activity might be influenced by the extraction conditions, such as the type of solvents and their concentration, the temperature, the time, and the stirring conditions. Using conventional extraction methodologies, Pinto et al. and Rodrigues et al. obtained similar extraction yields for hydroalcoholic extracts of bur (4.70% and 11.50% from Beira-Alta and Minho, respectively) and shell (4.10%
13.67% from different geographical origins), respectively (Rodrigues et al., 2015b; Pinto et al., 2017b). According to Va´zquez et al., the analysis of the response surfaces obtained for dependent variables could be a powerful tool in the selection of the best extraction conditions to prepare extracts with high extraction yields and antioxidant capacity (Va´zquez et al., 2012). Therefore this procedure has been described as useful for the optimization of the experimental conditions (Liyana-Pathirana and Shahidi, 2005). This study reported similar extraction yields for methanolic (10.52% 2 19.70%) and ethanolic (11.82% 2 18.93%) extracts of chestnut bur (Va´zquez et al., 2012). For both extracts the extraction conditions selected to obtain high yields and significant antioxidant capacity were solvent concentration of 50%, temperature of 75 C, and an extraction time of 30 and 75 min for ethanolic and methanolic extracts, respectively (Va´zquez et al., 2012). Another extraction methodology that has been reported is autohydrolysis using nonpolar solvents (Cruz et al., 1999). This procedure has two main purposes: (1) the separation of nonsaccharide compounds from monomeric, oligomeric, or polymeric soluble carbohydrates which result in a refined aqueous solution with improved potential for manufacturing prebiotic food additives or preparing fermentation media; and (2) the recovery of a soluble fraction in the organic solvent with improved antioxidant activity (Cruz et al., 1999). This environment-friendly procedure leads to a solid fraction (enriched in cellulose and acid-soluble lignin) appropriate for many applications. Moure et al. prepared chestnut bur extracts with absolute ethanol, a mixture of toluene:ethanol (2:1, v/v) or n-hexane using a Soxhlet apparatus, followed by a hydrolytic treatment (Moure et al., 2014). However, this unconventional process did not increase the extraction yields (1.25% 2 11.8%) compared with the previous studies cited. Furthermore, the most favorable operational conditions for antioxidant recovery from bur ethanolic extracts obtained by acid hydrolysis corresponded to 120 C, 0.5 h, and 0.5% H2SO4, while for the autohydrolysis process it was 120 C 2 130 C, 1 h, and 0% H2SO4. Even though both types of liquors had a high antioxidant activity, the fraction obtained by autohydrolysis at 120 C presented a high yield of phenolics, and is the hydrolytic treatment selected for burs processing (Moure et al., 2014). Applying a quite similar extraction, Conde et al. (2011) did not achieve an increase in extraction yield (5.64%) for chestnut bur. Several authors have reported biological activities for C. sativa bur, namely antioxidant activity. A study performed by Va´zquez et al. suggested a considerable antioxidant activity (determined by DPPH, ferric reduction antioxidant power (FRAP) and 2,20 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) antioxidant capacity assays) and TPC for methanolic and ethanolic extracts of chestnut bur, with the most remarkable properties being observed for methanolic extractions (Va´zquez et al., 2012). Based on extremely positive correlations observed between TPC and FRAP (r2 5 0.8923), DPPH (r2 5 0.8258), and ABTS (r2 5 0.7376), it was possible to conclude that the phenolic compounds contributed highly for the antioxidant activity of the extracts (Va´zquez et al., 2012). Otherwise slightly higher results were found by Pinto et al. (2017b) for TPC in hydroalcoholic extracts. Although Tra´s-os-Montes bur hydroalcoholic extract obtained a higher extraction yield (43.30%), Beira-Alta and Minho samples had the highest TPC (85.28 2 92.24 mg GAE/g db) and TFC (26.24 2 33.67 mg CEQ/g db). The differences between the outcomes can be explained by the changes in environmental conditions and soil composition. Regarding the antioxidant activity, the burs from Minho showed better results for DPPH (IC50 5 38.67 μg/mL) and FRAP (4510.4 μmol ferrous sulfate equivalent (FSE)/g db) assays (Pinto et al., 2017b). Another study analyzed bur extracts prepared with ethanol and toluene:ethanol (2:1, v/v) through a hydrolytic process and a final extraction with ethyl acetate (Moure et al., 2014). Bur ethanolic extracts obtained the best results for TPC (21.0 g GAE/100 g) and radical scavenging activity by DPPH (IC50 5 0.38 g/ L) (Moure et al., 2014). These extracts had a TPC similar to the ones reported by Va´zquez et al. (2012), while the antioxidant activity was lower than that reported by Pinto et al. (2017b). Likewise a freeze-dried bur ethyl acetate extract prepared by a nonisothermal autohydrolysis process presented similar radical scavenging activity against DPPH (IC50 5 346 mg/L) and a slightly higher TPC (0.43 g GAE/g) compared with the previous study (Conde et al., 2011). According to Moure et al. (2014), fatty acids, alcohols, and volatile phenols were the main volatile compounds present in bur ethanolic extracts, such as in Portuguese chestnut (Canas et al., 1999) and chestnut wood (Borges et al., 2007). Aldehydes (furfural and benzaldehyde), previously reported in chestnut flours (Cirlini et al., 2012), and terpenoids (3-oxo-α-ionol, α-cadinol, limonene and lupeol) were also identified (Moure et al., 2014). Additionally, lupeol was described as a component of the hexane extracts of C. sativa barks (Hafizo˘glu et al., 2002). Nevertheless, through a reverse phase HPLC-ESI-TOF mass spectrometry, it was possible to identify in methanol: water and ethanol:water bur extracts gallic acid esters of glucose (mono-, di-, and trigalloyl glucoses, m/z 331, m/z 481, and m/z 631, respectively), ellagic acid (m/z 301), and quercetin-3-β-Ɒ-glucoside (m/z 463) (Va´zquez et al., 2012). These phenolic compounds have demonstrated antioxidant properties, highlighting the phytochemical composition as

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responsible for the antioxidant properties of chestnut bur extracts (Va´zquez et al., 2012). In contrast to coffee silverskin (Rodrigues et al., 2015a) or Medicago sativa extracts (Rodrigues et al., 2014), chestnut bur did not present isoflavones in its composition (Pinto et al., 2017b). On the other hand, Conde et al. (2011) analyzed the phytochemical profile of ethyl acetate extracts from different vegetable wastes through HPLC-DAD, describing a higher amount of phenolic acids (31.07 mg/g) and flavonoids (6.96 mg/g) in C. sativa bur than in eucalypt wood, almond shells, or grape pomace. In chestnut bur extract, it was possible to identified nine phenolic compounds, with gallic acid (26.58 mg/g db) being the main phenolic acid, whereas rutin (4.23 mg/g db) was the main flavonoid (Conde et al., 2011). Moreover, two sugar-derived compounds, hydroxymethylfurfural and 2-furfuraldehyde, were also reported (Conde et al., 2011). During the hydrothermal process hemicelluloses present in lignocellulosic materials are partially hydrolyzed and decomposed, generating sugar degradation compounds such as furfural and 5-hydroxymethylfurfural, resulting from the dehydration of pentoses and hexoses, respectively (Conde et al., 2011). Similarly to chestnut shell (Rodrigues et al., 2015b), the bur did not reveal inhibitory activity against Gram-positive (Staphylococcus aureus and S. epidermidis) and Gram negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) or yeasts (C. albicans) (Pinto et al., 2017b). In order to evaluate the safeness of chestnut bur extracts, Pinto et al. (2017b) selected keratinocyte (HaCaT) cells as suitable for testing the toxicity potential of substances or products intended for dermatological use. Based on the results, chestnut bur hydroalcoholic extract from Tra´s-os-Montes did not achieve a cytotoxic effect until reaching a concentration of 100 μg/mL, and was considered as safe for skin application (Pinto et al., 2017b). With regards to the use of this chestnut by-product for food purposes, Zamuz et al. suggested an appropriate combination of chestnut extracts from different parts (bur, leaf, and hull) as a substitute for commercial antioxidants (Zamuz et al., 2018). The incorporation of chestnut extracts in beef meat patties inhibited lipid oxidation and retarded the formation of metmyoglobin, without significant changes on sensorial properties, also extending the shelf life of these products (Zamuz et al., 2018). Besides the actual application of these lignocellulosic residues in biomass refining, recent studies suggested the application of C. sativa bur for other purposes based on the richness in bioactive compounds (Balboa et al., 2014; Pinto et al., 2017b). Briefly, the substantial amount of carbohydrates and low fat content support the potential of this byproduct as an useful ingredient for the food industry (Pinto et al., 2017b). On the other hand, the high HaCaT viability in the presence of these extracts encourage its application in the cosmetic field (Pinto et al., 2017b). The richness in vitamin E and phenolic compounds associated with the substantial antioxidant activity confirmed the potential of chestnut bur as a new supplier of bioactive compounds for the development of novel applications (Pinto et al., 2017b). Nowadays antioxidants are appealing ingredients in cosmetic products since they can protect against lipid oxidation that might cause rancidity and undesirable changes in the texture, appearance, and quality of cosmetic products. Due to the high susceptibility of emulsified lipids to oxidation, the combination of antioxidant techniques could be effective in retarding lipid oxidation, improving the shelf life and quality of the emulsion systems (Waraho et al., 2011). Balboa et al. (2014) and Pinto et al. (2017a) evaluated the potential of chestnut bur extracts to be incorporated in cosmetic formulations. Using the same extraction technique and solvents employed by Conde et al. (2011), chestnut bur autohydrolysis extract was prepared and added as an antioxidant in the cosmetics preparations (Balboa et al., 2014). These extracts were rich in phenolic compounds (56.0 g/100 g) and showed in vitro antioxidant properties, measured as radical scavenging activity (DPPH: IC50 5 0.297 mg/mL; Trolox equivalent antioxidant capacity (TEAC): 1.13 g of TEs/g), reducing power (FRAP: 574.59 μM FSE), and protection of oxidation in a β-carotene-linoleic acid emulsion (β-carotene (antioxidant activity coefficient): 769.04) comparable to commercial antioxidants. The skin-irritation effects using reconstructed human tissues also confirms the safeness for topical application. The incorporation of chestnut bur extract at 0.4%
0.5% in an oil-in-water emulsion (avocado cream) inhibited the lipid oxidation (97.64%) during storage (after 34 days), providing a protective effect of cell systems against oxidation (Balboa et al., 2014). In fact, the extracts with higher phenolic content, such as chestnut bur extracts, inhibited the lipid oxidation more effectively. Based on these properties, it is possible to conclude that C. sativa bur extract might be a good candidate for use as natural antioxidants in cosmetic products. Compared with synthetic antioxidants, chestnut bur extracts used in this work could be added at higher levels due to their nontoxic character, which supports their use in cosmeceutical preparations also associated with a strong antioxidant activity and concomitant bioactivities (Balboa et al., 2014). In O/W emulsions, polysaccharides (such as those present in chestnut bur) inhibit the lipid oxidation by free radical scavenging, viscosity enhancement, and chelation through decreasing metal reactivity or partitioning the metal away from the lipid. Regarding the antioxidant activity in cell systems, rat red blood cells were used as a model to investigate the oxidative damage in biomembranes based on their susceptibility to peroxidation. Thus chestnut bur extract was the most efficient inhibitor of

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hemolysis induced by APPH (IC50 5 48.2 μg/mL) (Balboa et al., 2014). The TBARS method was used to measure the in vitro inhibition of lipid peroxidation on erythrocytes, being representative for skin oxidative stress (Andreassi and Andreassi, 2003; Polefka et al., 2012). A low protection against H2O2 lipid peroxidation was observed. The differences in these two antioxidant activity methodologies could be explained by the different hemolytic mechanisms used by the two oxidants (thiobarbituric acid versus 2,2’-azobis(2-amidinopropane (AAPH)) once thiobarbituric acid causes both lipid and protein oxidation. In order to evaluate the potential of the extracts for topical use, irritability assays employing Episkin test (RhE-models using human keratinocytes) were performed (Balboa et al., 2014). An inflammatory cascade is activated during the in vivo skin irritation, with the decrease in cell viability and the release of cytokine interleukin1α (IL-1α) being some of the indicative signals. Since irritant substances cause a decrease in cell viability, chestnut bur extract was identified as a nonirritant for topical use in cosmetic formulations at 0.1% based on a cell viability higher than 50% and a low release of IL-1α (Balboa et al., 2014). Also Pinto et al. (2017a) suggested the reuse of this undervalued by-product as a promising ingredient for cosmetic formulations. In fact C. sativa bur was described as an excellent source of phytochemicals with beneficial health effects in skincare formulations, contributing to the advance of cosmetic industries and, simultaneously, to environmental and economic sustainability. In the study performed by Pinto et al. different percentages of bur hydroalcoholic extracts were incorporated in a hydrogel base (Pinto et al., 2017a). A proportional ratio between the extract concentrations added to the hydrogel and the TPC, TFC, and antioxidant activity was observed. The gel with 50% of extract was selected as the best one for potential cosmetic purposes due to its high TPC, TFC, and antioxidant activity, the appropriate pH to skin application, and its good technological properties (Pinto et al., 2017a). Therefore Balboa et al. (2014) and Pinto et al. (2017a) suggested that chestnut bur extracts are good candidates to be considered for use in cosmetic formulations. Finally, Lee et al. (2005) produced chestnut bur-like particles covered with zinc oxide (ZnO) nanowires by thermal oxidation of metallic Zn particles in air. These particles seem to have ultrahigh surface sensitivity based on their large surface area, suggesting that they might provide a possibility to produce chemical sensors with high sensitivity and probably afford a novel practical application for optoelectronic devices (Lee et al., 2005). Another application of this forest waste as a biosorbent for the removal of cationic heavy metals was also described by Kim et al. (2015), highlighting the high uptake capacity of Cd(II) and Pb(II).

6.3

Future perspectives

In this chapter it has been well-documented that the different chestnut by-products have a diversity of interesting compounds with promising applications in different fields. Nevertheless, the main concern that surrounds the use of these different by-products (and in general all food by-products) is toxicity. In fact the bioavailability and toxicity of food byproducts need to be carefully assessed by in vitro and in vivo assays prior to being used in the different fields. For example, the richness in antioxidants raises their possible use in the cosmetic field as antiaging products. However, the European legislation (Regulation (EC) No. 1223/2009) is very restrictive (EU, 2009). The animal tests are forbidden not only for cosmetic products but also for cosmetic ingredients, which leads to the use of new in vitro models to assess the safety of new ingredients (Almeida et al., 2017). Also, according to the Scientific Committee on Consumer Safety (SCCS), the evaluation of a new ingredient for cosmetic purposes should focus on (1) acute toxicity; (2) corrosivity and irritation; (3) skin sensitization; (4) dermal/percutaneous absorption; (5) repeated dose toxicity; (6) reproductive toxicity; (7) mutagenicity/genotoxicity; (8) carcinogenicity; (9) toxicokinetics studies; (10) photoinduced toxicity; and (11) human data (SCCS, 2015). As it is possible to observe in this chapter, few assays have been performed with chestnut by-products, opening new fields of research. Further studies should be performed in order to guarantee the safety of these new cosmetic ingredients. In addition, the isolation of compounds using green techniques could represent a solution for solubility and bioavailability concerns. Most of the studies performed until now have only focused on traditional extraction techniques but more robust and new techniques could be employed to improve the extraction yields or to isolate specific compounds. Also these processes should be green and ecofriendly, allowing a decrease in the negative impacts of wastes on the environment and providing other economical advantages for companies.

6.4

Conclusion

This chapter summarizes the state-of-the-art of the different C. sativa Mill. by-products—leaves, flowers, shells, and burs—summarizing not only the chemical composition but also the different applications already evaluated. In addition, the future perspectives of applications are reviewed. Chestnut is one of the most consumed fruits in Europe, generating huge amounts of by-products during processing. Taking into account the concept of sustainability that involves not only

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the economy, but also society and environment, the effective reuse of chestnut by-products is extremely important. In this chapter different applications have been suggested based on the bioactive compounds reported, particularly phenolic compounds, flavonoids, and tannins. Most of them have been reported to exhibit beneficial properties in the cosmetic field, for example, due to their antioxidants that scavenge radical species, suggesting their incorporation in topical formulations for the prevention and treatment of skin oxidative stress-mediated diseases. Other fields, such as the leather industry, are also suggested. Nevertheless, further studies are requested, particularly in vitro and in vivo assays, to allow their incorporation in final formulations.

Acknowledgments This work received financial support from project PTDC/ASP-AGR/29277/2017-Castanea sativa shells as a new source of active ingredients for Functional Food and Cosmetic applications: a sustainable approach, supported by national funds by FCT/MCTES and cosupported by Fundo Europeu de Desenvolvimento Regional (FEDER) throughout COMPETE 2020—Programa Operacional Competitividade e Internacionalizac¸a˜o (POCI-01-0145-FEDER-029277). Diana Pinto is thankful for the research grant from project POCI-01-0145-FEDER029277. The work was also supported by UID/QUI/50006/2019 with funding from FCT/MCTES through national funds.

References Aboul-Enein, H.Y., Kruk, I., Kladna, A., Lichszteld, K., Michalska, T., 2007. Scavenging effects of phenolic compounds on reactive oxygen species. Biopolymers 86 (3), 222
230. Alissandrakis, E., Tarantilis, P.A., Pappas, C., Harizanis, P.C., Polissiou, M., 2011. Investigation of organic extractives from unifloral chestnut (Castanea sativa L.) and eucalyptus (Eucalyptus globulus Labill.) honeys and flowers to identification of botanical marker compounds. LWTFood Sci. Technol. 44 (4), 1042
1051. Almeida, I.F., Fernandes, E., Lima, J.L., Costa, P.C., Bahia, M.F., 2008a. Protective effect of Castanea sativa and Quercus robur leaf extracts against oxygen and nitrogen reactive species. J. Photochem. Photobiol. B 91 (2-3), 87
95. Almeida, I.F., Valentao, P., Andrade, P.B., Seabra, R.M., Pereira, T.M., Amaral, M.H., et al., 2008b. In vivo skin irritation potential of a Castanea sativa (Chestnut) leaf extract, a putative natural antioxidant for topical application. Basic Clin. Pharmacol. Toxicol. 103 (5), 461
467. Almeida, I.F., Costa, P.C., Bahia, M.F., 2010. Evaluation of functional stability and batch-to-batch reproducibility of a Castanea sativa leaf extract with antioxidant activity. AAPS PharmSciTech 11 (1), 120
125. Almeida, I.F., Pinto, A.S., Monteiro, C., Monteiro, H., Belo, L., Fernandes, J., et al., 2015a. Protective effect of C. sativa leaf extract against UV mediated-DNA damage in a human keratinocyte cell line. J. Photochem. Photobiol. B 144, 28
34. Almeida, I.F., Maleckova, J., Saffi, R., Monteiro, H., Goios, F., Amaral, M.H., et al., 2015b. Characterization of an antioxidant surfactant-free topical formulation containing Castanea sativa leaf extract. Drug Dev. Ind. Pharm. 41 (1), 148
155. Almeida, A., Sarmento, B., Rodrigues, F., 2017. Insights on in vitro models for safety and toxicity assessment of cosmetic ingredients. Int. J. Pharm. 519 (1-2), 178
185. Almeida, D., Pinto, D., Santos, J., Vinha, A.F., Palmeira, J., Ferreira, H.N., et al., 2018. Hardy kiwifruit leaves (Actinidia arguta): an extraordinary source of value-added compounds for food industry. Food Chem. 259, 113
121. Andreassi, M., Andreassi, L., 2003. Antioxidants in dermocosmetology: from the laboratory to clinical application. J. Cosmet. Dermatol. 2 (3-4), 153
160. Baier, J., Maisch, T., Maier, M., Landthaler, M., Baumler, W., 2007. Direct detection of singlet oxygen generated by UVA irradiation in human cells and skin. J. Invest. Dermatol. 127 (6), 1498
1506. Balboa, E.M., Soto, M.L., Nogueira, D.R., Gonza´lez-Lo´pez, N., Conde, E., Moure, A., et al., 2014. Potential of antioxidant extracts produced by aqueous processing of renewable resources for the formulation of cosmetics. Ind. Crops Prod. 58, 104
110. Barreira, J.C.M., Ferreira, I.C.F.R., Oliveira, M.B.P.P., Pereira, J.A., 2008. Antioxidant activities of the extracts from chestnut flower, leaf, skins and fruit. Food Chem. 107 (3), 1106
1113. Barreira, J.C.M., Alves, R.C., Casal, S., Ferreira, I.C.F.R., Oliveira, M.B.P.P., Pereira, J.A., 2009. Vitamin E profile as a reliable authenticity discrimination factor between chestnut (Castanea sativa Mill.) cultivars. J. Agric. Food Chem. 57 (12), 5524
5528. Barreira, J.C.M., Ferreira, I.C.F.R., Oliveira, M.B.P.P., Pereira, J.A., 2010a. Antioxidant potential of chestnut (Castanea sativa L.) and almond (Prunus dulcis L.) by-products. Food Sci. Technol. Int. 16 (3), 209
216. Barreira, J.C., Ferreira, I.C., Oliveira, M.B., Pereira, J.A., 2010b. Antioxidant potential of chestnut (Castanea sativa L.) and almond (Prunus dulcis L.) by-products. Food Sci. Technol. Int. 16 (3), 209
216. Barrera, G., 2012. Oxidative stress and lipid peroxidation products in cancer progression and therapy. ISRN Oncol. 2012, 137289. Barreira, J.C.M., Casal, S., Ferreira, I.C.F.R., Peres, A.M., Pereira, J.A., Oliveira, M.B.P.P., 2012. Chemical characterization of chestnut cultivars from three consecutive years: chemometrics and contribution for authentication. Food Chem. Toxicol. 50 (7), 2311
2317. Barros, L., Oliveira, S., Carvalho, A.M., Ferreira, I.C.F.R., 2010. In vitro antioxidant properties and characterization in nutrients and phytochemicals of six medicinal plants from the Portuguese folk medicine. Ind. Crops Prod. 32 (3), 572
579.

142

Valorization of Fruit Processing By-products

Barros, L., Alves, C.T., Duen˜as, M., Silva, S., Oliveira, R., Carvalho, A.M., et al., 2013. Characterization of phenolic compounds in wild medicinal flowers from Portugal by HPLC
DAD
ESI/MS and evaluation of antifungal properties. Ind. Crops Prod. 44, 104
110. Basile, A., Sorbo, S., Giordano, S., Ricciardi, L., Ferrara, S., Montesano, D., et al., 2000. Antibacterial and allelopathic activity of extract from Castanea sativa leaves. Fitoterapia 71 (Suppl. 1), S110
S116. Behrens, A., Giljum, S., Kovanda, J., Niza, S., 2007. The material basis of the global economy: worldwide patterns of natural resource extraction and their implications for sustainable resource use policies. Ecol. Econ. 64 (2), 444
453. Bilal, M., Shah, J.A., Ashfaq, T., Gardazi, S.M.H., Tahir, A.A., Pervez, A., et al., 2013. Waste biomass adsorbents for copper removal from industrial wastewater—a review. J. Hazard. Mater. 263 (Part 2), 322
333. Boeing, J.S., Ribeiro, D., Chiste, R.C., Visentainer, J.V., Costa, V.M., Freitas, M., et al., 2017. Chemical characterization and protective effect of the Bactris setosa Mart. fruit against oxidative/nitrosative stress. Food Chem. 220, 427
437. Borges, O.P., Soeiro Carvalho, J., Reis Correia, P., Paula Silva, A., 2007. Lipid and fatty acid profiles of Castanea sativa Mill. Chestnuts of 17 native Portuguese cultivars. J. Food Compos. Anal. 20 (2), 80
89. Borrelli, R.C., Esposito, F., Napolitano, A., Ritieni, A., Fogliano, V., 2004. Characterization of a new potential functional ingredient: coffee silverskin. J. Agric. Food Chem. 52 (5), 1338
1343. Braga, N., Rodrigues, F., Oliveira, M.B.P.P., 2015. Castanea sativa by-products: a review on added value and sustainable application. Nat. Prod. Res. 29 (1), 1
18. Calliste, C.A., Trouillas, P., Allais, D.P., Duroux, J.L., 2005. Castanea sativa Mill. leaves as new sources of natural antioxidant: an electronic spin resonance study. J. Agric. Food Chem. 53 (2), 282
288. Canas, S., Leandro, M.C., Spranger, M.I., Belchior, A.P., 1999. Low molecular weight organic compounds of chestnut wood (Castanea sativa L.) and corresponding aged brandies. J. Agric. Food Chem. 47 (12), 5023
5030. Carocho, M., Barreira, J.C., Bento, A., Morales, P., Ferreira, I.C., 2014a. Chestnut flowers as functionalizing agents to enhance the antioxidant properties of highly appreciated traditional pastry. Food Funct. 5 (11), 2989
2995. Carocho, M., Barros, L., Bento, A., Santos-Buelga, C., Morales, P., Ferreira, I.C.F.R., 2014b. Castanea sativa Mill. Flowers amongst the most powerful antioxidant matrices: a phytochemical approach in decoctions and infusions. BioMed. Res. Int. . Available from: https://doi.org/10.1155/2014/ 232956Article ID: 232956, 232957 pages). Carocho, M., Calhelha, R.C., Queiroz, M.-J.R.P., Bento, A., Morales, P., Sokovi´c, M., et al., 2014c. Infusions and decoctions of Castanea sativa flowers as effective antitumor and antimicrobial matrices. Ind. Crops Prod. 62, 42
46. Carocho, M., Barreira, J.C.M., Barros, L., Bento, A., Ca´mara, M., Morales, P., et al., 2015. Traditional pastry with chestnut flowers as natural ingredients: an approach of the effects on nutritional value and chemical composition. J. Food Compos. Anal. 44, 93
101. Cirlini, M., Dall’asta, C., Silvanini, A., Beghe, D., Fabbri, A., Galaverna, G., et al., 2012. Volatile fingerprinting of chestnut flours from traditional Emilia Romagna (Italy) cultivars. Food Chem. 134 (2), 662
668. Conde, E., Moure, A., Domı´nguez, H., Parajo´, J.C., 2011. Production of antioxidants by non-isothermal autohydrolysis of lignocellulosic wastes. LWT-Food Sci. Technol. 44 (2), 436
442. Cruz, J.M., Domı´nguez, J.M., Domı´nguez, H., Parajo´, J.C., 1999. Solvent extraction of hemicellulosic wood hydrolysates: a procedure useful for obtaining both detoxified fermentation media and polyphenols with antioxidant activity. Food Chem. 67, 147
153. Cruz, B.R., Abraa˜o, A.S., Lemos, A.M., Nunes, F.M., 2013. Chemical composition and functional properties of native chestnut starch (Castanea sativa Mill). Carbohydr. Polym. 94 (1), 594
602. Dawidowicz, A.L., Wianowska, D., Baraniak, B., 2006. The antioxidant properties of alcoholic extracts from Sambucus nigra L. (antioxidant properties of extracts). LWT-Food Sci. Technol. 39 (3), 308
315. Day, L., Seymour, R.B., Pitts, K.F., Konczak, I., Lundin, L., 2009. Incorporation of functional ingredients into foods. Trends Food Sci. Technol. 20 (9), 388
395. Demirbas, A., 2008. Heavy metal adsorption onto agro-based waste materials: a review. J. Hazard. Mater. 157 (2), 220
229. Demirkesen, I., Mert, B., Sumnu, G., Sahin, S., 2010. Utilization of chestnut flour in gluten-free bread formulations. J. Food Eng. 101 (3), 329
336. de Vasconcelos, M.D.C.B.M., Bennett, R.N., Quideau, S., Jacquet, R., Rosa, E.A.S., Ferreira-Cardoso, J.V., 2010. Evaluating the potential of chestnut (Castanea sativa Mill.) fruit pericarp and integument as a source of tocopherols, pigments and polyphenols. Ind. Crops Prod. 31 (2), 301
311. Dewick, P.M., 2002. Medicinal Natural Products. John Wiley and Sons, Lda. Dı´az-Reinoso, B., Moure, A., Domı´nguez, H., Parajo´, J.C., 2011. Membrane concentration of antioxidants from Castanea sativa leaves aqueous extracts. Chem. Eng. J. 175, 95
102. Dı´az Reinoso, B., Couto, D., Moure, A., Fernandes, E., Domı´nguez, H., Parajo´, J.C., 2012. Optimization of antioxidants
extraction from Castanea sativa leaves. Chem. Eng. J. 203, 101
109. EU, 2009. Regulation (EC) No. 1223/2009 of the European Parliament and of the Council of 30 November 2009 on Cosmetic Products. European Parliament and Council of European Union - Official Journal of the European Union, Brussels. EU, 2017. EU Sustainable Development Strategy. European Commission, Brussels. Elleuch, M., Bedigian, D., Roiseux, O., Besbes, S., Blecker, C., Attia, H., 2011. Dietary fibre and fibre-rich by-products of food processing: characterisation, technological functionality and commercial applications: a review. Food Chem. 124 (2), 411
421. Esteve, C., Marina, M.L., Garcı´a, M.C., 2015. Novel strategy for the revalorization of olive (Olea europaea) residues based on the extraction of bioactive peptides. Food Chem. 167, 272
280. FAO, 2019. From ,http://www.fao.org/faostat/en/?fbclid 5 IwAR0HODyYs-D3AYvKVIjfi3cUdlDYfkQjpT3tjtN5IE9KUkB38Im_TUUxZMY#data/ QC/visualize..

Chestnut Chapter | 6

143

Filipe, P., Silva, J.N., Haigle, J., Freitas, J.P., Fernandes, A., Santus, R., et al., 2005. Contrasting action of flavonoids on phototoxic effects induced in human skin fibroblasts by UVA alone or UVA plus cyamemazine, a phototoxic neuroleptic. Photochem. Photobiol. Sci. 4 (5), 420
428. Foley, S., Navaratnam, S., McGarvey, D.J., Land, E.J., Truscott, T.G., Rice-Evans, C.A., 1999. Singlet oxygen quenching and the redox properties of hydroxycinnamic acids. Free Radic. Biol. Med. 26 (9
10), 1202
1208. Gullo´n, B., Eibes, G., Da´vila, I., Moreira, M.T., Labidi, J., Gullo´n, P., 2018. Hydrothermal treatment of chestnut shells (Castanea sativa) to produce oligosaccharides and antioxidant compounds. Carbohydr. Polym. 192, 75
83. Hafizo˘glu, H., Holmbom, B., Reunanen, M., 2002. Chemical composition of lipophilic and phenolic constituents of barks from Pinus nigra, Abies bornmu¨lleriana and Castanea sativa. Holzforschung 56, 257. Ham, J.-S., Kim, H.-Y., Lim, S.-T., 2015. Antioxidant and deodorizing activities of phenolic components in chestnut inner shell extracts. Ind. Crops Prod. 73, 99
105. Hasanuzzaman, M., Nahar, K., Fujita, M., 2014. Chapter 12: role of tocopherol (vitamin E) in plants: abiotic stress tolerance and beyond. In: Rasool, S. (Ed.), Emerging Technologies and Management of Crop Stress Tolerance. Academic Press, San Diego, pp. 267
289. Hseu, Y.C., Chou, C.W., Senthil Kumar, K.J., Fu, K.T., Wang, H.M., Hsu, L.S., et al., 2012. Ellagic acid protects human keratinocyte (HaCaT) cells against UVA-induced oxidative stress and apoptosis through the upregulation of the HO-1 and Nrf-2 antioxidant genes. Food Chem. Toxicol. 50 (5), 1245
1255. Kanu, P.J., Zhu, K., Kanu, J.B., Zhou, H., Qian, H., Zhu, K., 2007. Biologically active components and nutraceuticals in sesame and related products: a review and prospect. Trends Food Sci. Technol. 18, 599
608. Kim, N., Park, M., Park, D., 2015. A new efficient forest biowaste as biosorbent for removal of cationic heavy metals. Bioresour. Technol. 175, 629
632. Lang, P., Dane, F., Kubisiak, T.L., Huang, H., 2007. Molecular evidence for an Asian origin and a unique westward migration of species in the genus Castanea via Europe to North America. Mol. Phylogenet. Evol. 43 (1), 49
59. Le Corre, L., Chalabi, N., Delort, L., Bignon, Y.J., Bernard-Gallon, D.J., 2005. Resveratrol and breast cancer chemoprevention: molecular mechanisms. Mol. Nutr. Food Res. 49 (5), 462
471. Le Marchand, L., 2002. Cancer preventive effects of flavonoids
a review. Biomed. Pharmacother. 56 (6), 296
301. Lee, G.H., Jeon, H.D., Lee, W.J., Shin, B.C., Kim, I.S., 2005. Fabrication of chestnut bur-like particles covered with ZnO nanowires. J. Cryst. Growth 277 (1), 1
5. Liyana-Pathirana, C., Shahidi, F., 2005. Optimization of extraction of phenolic compounds from wheat using response surface methodology. Food Chem. 93 (1), 47
56. Loden, M., Wessman, W., 2001. The influence of a cream containing 20% glycerin and its vehicle on skin barrier properties. Int. J. Cosmet. Sci. 23 (2), 115
119. Madhava Naidu, M., Shyamala, B.N., Pura Naik, J., Sulochanamma, G., Srinivas, P., 2011. Chemical composition and antioxidant activity of the husk and endosperm of fenugreek seeds. LWT-Food Sci. Technol. 44 (2), 451
456. Marangi, F., Pinto, D., de Francisco, L., Alves, R.C., Puga, H., Sut, S., et al., 2018. Hardy kiwi leaves extracted by multi-frequency multimode modulated technology: a sustainable and promising by-product for industry. Food Res. Int. 112, 184
191. Masaki, H., Atsumi, T., Sakurai, H., 1995. Detection of hydrogen peroxide and hydroxyl radicals in murine skin fibroblasts under UVB irradiation. Biochem. Biophys. Res. Commun. 206 (2), 474
479. Matsuo, M., Sasaki, N., Saga, K., Kaneko, T., 2005. Cytotoxicity of flavonoids toward cultured normal human cells. Biol. Pharm. Bull. 28 (2), 253
259. Miliauskas, G., Venskutonis, P.R., van Beek, T.A., 2004. Screening of radical scavenging activity of some medicinal and aromatic plant extracts. Food Chem. 85 (2), 231
237. Moure, A., Conde, E., Falque´, E., Domı´nguez, H., Parajo´, J.C., 2014. Production of nutraceutics from chestnut burs by hydrolytic treatment. Food Res. Int. 65, 359
366. Moussa, S.A., 2008. Oxidative stress in diabetes mellitus. Rom. J. Biophys. 18, 225
236. ˇ Muji´c, A., Grdovi´c, N., Muji´c, I., Mihailovi´c, M., Zivkovi´ c, J., Poznanovi´c, G., et al., 2011. Antioxidative effects of phenolic extracts from chestnut leaves, catkins and spiny burs in streptozotocin-treated rat pancreatic β-cells. Food Chem. 125 (3), 841
849. Nations, U., 2018. Transforming our world: the 2030 agenda for sustainable development, from ,https://sustainabledevelopment.un.org/content/documents/21252030%20Agenda%20for%20Sustainable%20Development%20web.pdf. Neves, J.M., Matos, C., Moutinho, C., Queiroz, G., Gomes, L.R., 2009. Ethnopharmacological notes about ancient uses of medicinal plants in Tras-osMontes (northern of Portugal). J. Ethnopharmacol. 124 (2), 270
283. Nunes, M.A., Rodrigues, F., Oliveira, M.B.P.P., 2017. 11
grape processing by-products as active ingredients for cosmetic proposes A2. In: Charis, M. (Ed.), Handbook of Grape Processing By-Products. Academic Press, pp. 267
292. Ozcimen, D., Ersoy-Mericboyu, A., 2009. Removal of copper from aqueous solutions by adsorption onto chestnut shell and grapeseed activated carbons. J. Hazard. Mater. 168 (2-3), 1118
1125. O’Connell, D.W., Birkinshaw, C., O’Dwyer, T.F., 2008. Heavy metal adsorbents prepared from the modification of cellulose: a review. Bioresour. Technol. 99 (15), 6709
6724. Patent CN102334573 B, Chestnut flower composite tea drink and preparation method thereof, Available from https://www.patents.google.com/patent/ CN102334573B/en?oq 5 chestnut 1 flower Patent CN102524895 B,Chestnut flower beverage, Available from https://www.patents.google.com/patent/CN102524895B/en?oq 5 chestnut 1 flower

144

Valorization of Fruit Processing By-products

Pereira, C., Barros, L., Carvalho, A.M., Ferreira, I.C.F.R., 2013. Use of UFLC-PDA for the analysis of organic acids in thirty-five species of food and medicinal plants. Food Anal. Methods 6, 1337
1344. Pinto, D., Braga, N., Rodrigues, F., Beatriz, M., Oliveira, P.P., 2017a. Castanea sativa Bur: an undervalued by-product but a promising cosmetic ingredient. Cosmetics 4 (4), 50. Pinto, D., Rodrigues, F., Braga, N., Santos, J., Pimentel, F.B., Palmeira-de-Oliveira, A., et al., 2017b. The Castanea sativa bur as a new potential ingredient for nutraceutical and cosmetic outcomes: preliminary studies. Food Funct. 8 (1), 201
208. Polefka, T.G., Meyer, T.A., Agin, P.P., Bianchini, R.J., 2012. Cutaneous oxidative stress. J. Cosmet. Dermatol. 11 (1), 55
64. Proniuk, S., Blanchard, J., 2002. Anhydrous carbopol polymer gels for the topical delivery of oxygen/water sensitive compounds. Pharm. Dev. Technol. 7 (2), 249
255. Rizza, L., Bonina, C., Frasca, G., Puglia, C., 2012. Skin-whitening effects of mediterranean herbal extracts by in vitro and in vivo models. J. Cosmet. Sci. 63 (5), 311
320. Rodrigues, F., Almeida, I., Sarmento, B., Amaral, M.H., Oliveira, M.B.P.P., 2014. Study of the isoflavone content of different extracts of Medicago spp. as potential active ingredient. Ind. Crops Prod. 57, 110
115. Rodrigues, F., Palmeira-de-Oliveira, A., das Neves, J., Sarmento, B., Amaral, M.H., Oliveira, M.B., 2015a. Coffee silverskin: a possible valuable cosmetic ingredient. Pharm. Biol. 53 (3), 386
394. Rodrigues, F., Santos, J., Pimentel, F.B., Braga, N., Palmeira-de-Oliveira, A., Oliveira, M.B., 2015b. Promising new applications of Castanea sativa shell: nutritional composition, antioxidant activity, amino acids and vitamin E profile. Food Funct. 6 (8), 2854
2860. SCCS, 2015. The SCCS’s Notes of Guidance for the Testing of Cosmetic Substances and Their Safety Evaluation. S.C.o.C Safety, Brussels, p. 133p, European Comission. Sakurai, H., Yasui, H., Yamada, Y., Nishimura, H., Shigemoto, M., 2005. Detection of reactive oxygen species in the skin of live mice and rats exposed to UVA light: a research review on chemiluminescence and trials for UVA protection. Photochem. Photobiol. Sci. 4 (9), 715
720. Squillaci, G., Apone, F., Sena, L.M., Carola, A., Tito, A., Bimonte, M., et al., 2018. Chestnut (Castanea sativa Mill.) industrial wastes as a valued bioresource for the production of active ingredients. Process Biochem. 64, 228
236. Va´zquez, G., Calvo, M., Sonia Freire, M., Gonza´lez-Alvarez, J., Antorrena, G., 2009a. Chestnut shell as heavy metal adsorbent: optimization study of lead, copper and zinc cations removal. J. Hazard. Mater. 172 (2
3), 1402
1414. Va´zquez, G., Gonza´lez-Alvarez, J., Santos, J., Freire, M.S., Antorrena, G., 2009b. Evaluation of potential applications for chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark extracts. Ind. Crops Prod. 29 (2
3), 364
370. ´ lvarez, J., 2012. Response surface optimization of antiVa´zquez, G., Ferna´ndez-Agullo´, A., Go´mez-Castro, C., Freire, M.S., Antorrena, G., Gonza´lez-A oxidants extraction from chestnut (Castanea sativa) bur. Ind. Crops Prod. 35 (1), 126
134. Waraho, T., McClements, D.J., Decker, E.A., 2011. Mechanisms of lipid oxidation in food dispersions. Trends Food Sci. Technol. 22 (1), 3
13. Zamuz, S., Lo´pez-Pedrouso, M., Barba, F.J., Lorenzo, J.M., Domı´nguez, H., Franco, D., 2018. Application of hull, bur and leaf chestnut extracts on the shelf-life of beef patties stored under MAP: evaluation of their impact on physicochemical properties, lipid oxidation, antioxidant, and antimicrobial potential. Food Res. Int. 112, 263
273. Zhang, J., Li, L., Kim, S.H., Hagerman, A.E., Lu, J., 2009. Anti-cancer, anti-diabetic and other pharmacologic and biological activities of pentagalloyl-glucose. Pharm. Res. 26 (9), 2066
2080. Zhao, Z., Egashira, Y., Sanada, H., 2005. Phenolic antioxidants richly contained in corn bran are slightly bioavailable in rats. J. Agric. Food Chem. 53 (12), 5030
5035. ˇ Zivkovi´ c, J., Zekovi´c, Z., Muji´c, I., Goðevac, D., Mojovi´c, M., Muji´c, A., et al., 2009. EPR spin-trapping and spin-probing spectroscopy in assessing antioxidant properties: example on extracts of catkin, leaves, and spiny burs of Castanea sativa. Food Biophys. 4 (2), 126
133. Zlatanov, M.D., Antova, G.A., Angelova-Romova, M.J., Teneva, O.T., 2013. Lipid composition of Castanea sativa Mill. and Aesculus hippocastanum fruit oils. J. Sci. Food Agric. 93 (3), 661
666. Zou, Y., Lu, Y., Wei, D., 2004. Antioxidant activity of a flavonoid-rich extract of Hypericum perforatum L. in vitro. J. Agric. Food Chem. 52 (16), 5032
5039.

Chapter 7

Citrus fruits Debajyoti Kundu1, Mohan Das1, Reddhy Mahle1, Pritha Biswas2, Sandipan Karmakar3 and Rintu Banerjee1 1

Department of Agricultural and Food Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India, 2School of Medical Science and

Technology, Indian Institute of Technology Kharagpur, Kharagpur, India, 3Xavier Institute of Management, Xavier University, Bhubaneswar, India

Chapter Outline 7.1 Introduction 7.2 Citrus fruit waste generation and management 7.3 Valorization of citrus waste 7.3.1 Recovery of phytochemicals/bioactive compounds 7.3.2 Recovery of essential oil 7.3.3 Recovery of energy 7.4 Other value-added products 7.4.1 Production of enzymes 7.4.2 Organic acid production

7.1

145 146 148 148 151 152 157 157 159

7.4.3 Dietary fibers production 7.4.4 Production of single cell protein 7.4.5 Candy preparation 7.5 Bioeconomy concept in citrus waste valorization 7.6 Future scope 7.7 Conclusion References Further reading

159 160 160 161 162 162 162 166

Introduction

Generation of food waste is a great concern from the social, economical, and environmental points of view. Advancements in waste management strategies and volume reduction processes are developing gradually all over the world. Primarily food waste has been produced in the whole food supply chain while major wastage has been found in its consumption and manufacturing stage. This food waste corresponds to a prospective source of value-added products which can replace the virgin resource (Cristo´bal et al., 2018). Among all the fruits, citrus fruits and juice have a great reputation for a large number of people as a nutritious food. The presence of vitamin C content in the fruits makes it more popular among the community (Kundu et al., 2018; Singh et al., 2019). Recently people are more concerned about bioactive compounds, which include vitamins, flavonoids, limonoids, phenolic acids, and volatile terpenoids that prevent different diseases. Citrus fruits contain all the constituents mentioned above which help to maintain good health (Berk, 2016). Basically “citrus” is a generic term. Different varieties of citrus genus like sweet oranges (Citrus sinensis), sour and bitter oranges (Citrus aurantium), pomelo (Citrus grandis), limon (Citrus limetta), sweet lime (Citrus limettioides), rough lemon (Citrus jambhiri), rangpur (Citrus limonia), citrus hybrid mandarin 3 pomelo (Citrus deliciosa), mandarins (Citrus reticulata), and Karna Nimbu/ Khatta Nimbu (Citrus karna) are some of the examples of citrus fruits (Sidana et al., 2013; Berk, 2016). In 2017, global production of citrus was 92,088,000 metric tons where oranges, tangerines, mandarins, and grapefruit comprised 51.86%, 32.60%, 7.20%, and 8.34%, respectively. USDA (2018) citrus data depicts 68.44% citrus is consumed while 21.51% is used for further processing. According to the FAO (2017) database, India holds the third rank in citrus production after China and Brazil. Although production of citrus in India includes all varieties of lemon but the most prominent varieties include oranges followed by lemons and grapefruits (Fig. 7.1). In India the production of citrus has increased by 1.3-fold since 2008. Further detail of the production, export, and import of citrus from 2008 is given in Fig. 7.1. It can be observed that along with the production of citrus, imports and exports has also increased. Approximately, a 10-fold increase in imports from 2008 to 2016 was established showing the increasing demand and popularity of citrus in India.

Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00007-1 © 2020 Elsevier Inc. All rights reserved.

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FIGURE 7.1 World production, export, and import of citrus varieties from 2008 to 2016.

Gigantic popularity and demand for citrus fruits led to the establishment of the enormous size of the fruit processing industry. Along with the food product development, these industries contribute a vast amount of waste into the environment. After the processing of raw fruits into different products, the citrus industry produces two types of waste, one is solid and the other is a liquid. Solid waste includes rotten fruits, peel, pulp, and seed, whereas wastewater comes from fruit washing, instrument and plant washing, cooling devices, oil extraction, etc. These huge amounts of wastes suffer from improper management and have led to environmental problems due to their open dumping. These waste materials contain different components like sugars, lipids, organic acids, carbohydrates, flavonoids, essential oil, vitamins, and minerals (Mamma and Christakopoulos, 2014). The characterization of citrus waste has revealed the presence of organic matter, sugar residues, and other potential residues for energy production. The world is in dire need of renewable energy due to the diminution of conventional sources of fuel and further environmental concerns. World fuel consumption is likely to increase to 115 million barrels/ day by 2040 and this increment corresponds to a 57% increment in the consumption of liquid fuel by the transportation sector (IEO, 2013). Biomass-derived fuels have invariably been utilized for a long time as a route or method to increase the energy predicament persisting in the world and also to strengthen agricultural waste management (Arau´jo et al., 2017). As citrus wastes contain different types of valuable components, they can be further utilized for energy and fertilizer production, thus improper disposal also accelerates economic loss. Hence the recovery of value-added products and energy production from the residue is a wise management approach targeting revenue generation. This book chapter discusses citrus waste valorization strategies for the sustainable production of phytochemicals, food materials, enzymes, energy, and biofertilizer. It also illustrates the role of citrus waste in revenue generation based on the bioeconomy concept.

7.2

Citrus fruit waste generation and management

Waste production is an integral part of any processing industry. Not only in the processing industry, it starts in postharvesting loss in cultivation. For the estimation of waste generation from the cultivation to end user, a conceptual framework considering the food supply chain (FSC) has been proposed by Cristo´bal et al. (2018). In the citrus processing industry only one third of citrus fruit is being processed. Oranges, grapefruits, and lemon are the dominant varieties

Citrus fruits Chapter | 7

147

FIGURE 7.2 An outline of waste generation in different citrus processing steps.

from which fruit juice are produced, as well as different products such as jam, jelly, pickles, flavonoids, and essential oils. These processed citrus fruits products are subjected to deliver in open market. Processing technology starts with receiving the fruits followed by washing, grading, sorting, and proper storage. In the different production steps of these various products, diverse composition of waste is generated (Calabro et al., 2017). Basically, citrus processing at the industrial scale involves four different operational stages (Sataria and Karimi, 2018): 1. 2. 3. 4.

harvesting and transportation to the industry gradation, sorting, and washing juice extraction and quality maintenance sterilization, labeling, and packing

During citrus processing the possible routes of waste generation from various units’ operations have been represented in Fig. 7.2. Based on the total industrial processing of citrus fruits, approximately 50% waste are being generated (Vergamini et al., 2015). By considering waste generation and observing the global citrus production data from USDA (2018) the estimated waste generated from citrus processing industries is 10,929.50 metric tons in 2016. With the increased production and processing in the citrus industry, the generation of the by-products has become a great concern as these organic materials are very much prone to microbial contamination. Solid waste generated from the industry has a low pH range from 3 to 4, high organic load of about 95%, and high moisture content (80%
90%). With regards to the proximate composition of the waste it contains 3.73%
4.75% ash, 22.9%
33.09% sugar, 15.30%
25% pectin, 1.95%
2.19% lignin, 8.82%
22% cellulose, and 7.96%
11.09% hemicelluloses (Pourbafrani et al., 2010; Satari et al., 2017). Apart from these, citrus waste contains a meager amount of fat, free sugar, organic acid, some amounts of enzymes, phytochemicals, essential oil, pigments, and organic acids (Sataria and Karimi, 2018). A typical composition of citrus waste has been elaborated in Table 7.1. Along with the enormous amount of solid waste, citrus processing industries also generate huge amounts of wastewater every day. This wastewater is characterized by the variability of its organic load, pH, flow, suspended and settable solids (as pulp and peel residues), soluble (mainly sugars and acid) and insoluble (essential oil) compounds, turbidity, color, and nutrient load. Qualitative attributes are the hydraulic loading, high chemical oxygen demand (COD) (10 g/L from oil extraction unit and 12 g/kg of processed fruit from processing unit), pH due to use of neutralizing agent, nutrients, etc. (Calabro et al., 2017). Hence the storage and transport of these by-products are also limiting factors. On the other hand, their utilization as fertilizer in crop production is infrequent (Vergamini et al., 2015). The disposal of waste materials is another issue that is strongly associated with detrimental environmental effects. Prior to disposal, pretreatment is necessary for these wastes in order to comply with environmental legislation. But apart from the disposal, a huge interest lies in the valorization of the waste materials for value-added product recovery. This practice expedites the utilization of citrus processing waste by others. Until now conventional disposal practices like open dumping in an adjacent area, animal feed production, or burning has led to several environmental, societal, and economic issues. However, open dumping of

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Valorization of Fruit Processing By-products

TABLE 7.1 Characteristics of dried and wet citrus fruit waste. Parameter

Dried citrus waste

Wet citrus waste

pH




3.9
4.3

Water content (%)

10.0
14.2

72.5
87.0

Volatile solid (% dry matter)

93.5
94.1

93.8
96.7

Protein (% dry matter)

3.3
8.5

6.53
8.3

Fat (% dry matter)

1.7
3.7

0.9
3.3

Fiber (% dry matter)

7.3
13.9

10.6
42.1

Neutral detergent fiber (% dry matter)

19.3
24.2

n.a

Acid detergent fiber (% dry matter)

16.0
22.2

n.a

Starch (% dry matter)

2.3

, 1.0
2.9

Sugar (% dry matter)

24.1
40.0

15.0
46.6

Organic C (% dry matter)

50

39

Total N (% dry matter)

1.3

1.5

C/N ratio (% dry matter)

38

26

P2O5 (% dry matter)

0.28

0.36

K2O (% dry matter)

1.1

1.5

Source: Data has been taken from Zema, D.A., Calabro`, P.S., Folino, A., Tamburino, V., Zappia, G., Zimbone, S.M., 2018. Valorisation of citrus processing waste: a review. Waste Manage. 80, 252
227 (Zema et al., 2018).

citrus waste or any other organic waste has been prohibited by EU directives, unless or until it goes through the valorizaton process. In this juncture alternative management practices help to maintain the balance between environmental and societal economics (Sataria and Karimi, 2018). A strategic approach of citrus waste management has been represented in Fig. 7.3.

7.3

Valorization of citrus waste

Juices from citrus fruit are widely enjoyed drinks around the world among all sections of society. As a result a huge amount of waste is generated after the extraction of juice. The residual biomass mostly consists of peel (flavedo and albedo), rag (membranes and cores), pulp (juice sac residues), and seeds. The biomolecular arrangement and composition are different from species to species of citrus fruits. Based on the processing industry, different components of the aforementioned feedstock act as the base material to be used as the by-product feedstock of citrus fruits (Mamma and Christakopoulos, 2014). The composition of citrus fruits mostly depends on a range of factors, including maturity of fruit, variety and type of citrus fruit, spatial and temporal conditions. However, in an overall perspective, citrus fruits consist of insoluble carbohydrates (pectin, cellulose), lipids (palmitic acid, oleic acid, linoleic acid, linolenic acid, stearic acid, phytosterol), organic acids (citric acid, malic acid, tartaric acid, benzoic acid, oxalic acid, succinic acid), simple sugars (glucose, sucrose, fructose), bitter components (limonin, isolimonin), flavonoids (naringin, hesperidin), volatile compounds, pigments, vitamins, and essential oils. All these are high added-value components that could be recovered and reutilized in further applications (Lv et al., 2015; Kundu et al., 2019).

7.3.1

Recovery of phytochemicals/bioactive compounds

Citrus fruits are generally considered as a “treasure trove” of biologically active metabolites. Pharmacological activities are mainly attributed to the secondary metabolites, which include alkaloids, coumarins, limonoids, flavonoids, carotenoids, and essentials oils. These pharmacogenic agents mostly possess positive effects on human health, acting as antioxidative, antiinflammatory, anticancer, neuroprotective, and cardioprotective agents (Das et al., 2018). Both Indian

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149

FIGURE 7.3 Strategic management of waste from the citrus processing industry.

FIGURE 7.4 Diagrammatic representation of transectorial anatomy of (A) Citrus limetta; (B) Citrus maxima; (C) Citrus sinensis; (D) Citrus limon Burm. f.; (E) Citrus aurantiifolia; and (F) Citrus medica.

and Chinese pharmacopeia consider several species of Citrus in traditional medicinal practices. The anatomy of some citrus fruits is depicted in Fig. 7.4. Lv et al. (2015) reported, about 48 flavonoids from 22 Citrus species belonging to five classes including flavones, flavanones, flavonols, flavanonols, and polymethoxylated flavones. Flavonoids derived from Citrus are mostly present in aglycone or glycoside forms (Lv et al., 2015; Putnik et al., 2017).

150

Valorization of Fruit Processing By-products

7.3.1.1 Ultrasound treatment Ultrasound-assisted extraction (UAE) of bioactive compounds from citrus waste is reported as a simple, reproducible, and economically viable process. The principle works on the basis of ultrasound’s ability to disrupt cell by cavitation. As a result, internal diffusion is accelerated which in turn increases mass transfer. Several researchers have reported that although intricate UAE conditions have to be maintained in this method, significant improvement in the recovery of bioactive compounds was observed in comparison to conservative technologies. Based on the reported literature, it is worth mentioning the positive impact of the technology but the bioactivity of the compounds is also to be considered. Qiao et al. (2014) studied the sonochemical effects on 14 flavonoids present commonly in citrus fruits. It has been observed that flavonoids like eriocitrin, eridictyol, hesperidin, neohesperidin, naringin, naringenin, narirutin, didymin, quercitrin, luteolin, nobiletin, tangeretin, and sinensetin were stable under ultrasound treatment but quercitin significantly degraded during such treatments. During ultrasound treatments, quercitin underwent four types of reactions: oxidation, addition, polymerization, and decomposition. On the other hand, Sun et al. (2011) evaluated the effects of particle size, temperature, extraction time, extraction solvent and its ratio, electrical acoustic intensity, duty cycle of exposure, and height of liquid in improving the efficiency of extraction of all-trans-β-carotene from the residual peel of citrus fruits by UAE technology. Particle size and solvent for extraction had significant effects on the yield of bioactive compounds. Ethanol showed significantly positive effects by enhancing yield, whereas dichloromethane had negative impact as it degrades all-trans-β-carotene. LondonoLondono et al. (2010) reported that the extraction of total phenolic compounds by UAE from tangerine (Citrus tangerine), orange, and lime obtained 58.68 6 4.01, 66.36 6 0.75, and 74.80 6 1.90 mg gallic acid equiv./g, respectively. Optimal conditions of 40 C temperature, 30 min extraction time, 60 kHz frequency, peel:water ratio 1:10 (g/mL), and Ca(OH)2 were standard parameters for UAE. Under these technical considerations, the total phenolic content extracted was 19.595 6 2.114 mg gallic acid equiv./g of dry matter (peel).

7.3.1.2 High-pressure-assisted extraction In this process air pores present in fruit tissues are mostly filled with liquid during the extraction process. During the release of pressure, blocked air is discharged, causing the breakage of cell membranes. Treatment with high pressure causes charged groups’ deprotonation and the disruption of hydrophobic bonds, which in turn causes protein denaturation and its conformational changes. This makes the cellular membranes more accessible to the desired compounds and enhances yield efficiency. While comparing the extraction yield of polyphenols, higher yields were obtained from orange and lemon peels in comparison to the control under operational conditions: 300 MPa/10 min; 500 MPa/3 min. Polyphenolic content was significantly higher in orange, except at 500 MPa. At more intense conditions of 500 MPa/ 10 min the total antioxidant activity (by 1,1-diphenyl-2-picrylhydrazyl) significantly decreased for both orange and lemon peels. In addition, the orange peel extracts have effective antimicrobial activity against a wide array of microbes (both Gram-positive and Gram-negative) (Putnik et al., 2017).

7.3.1.3 Microwave-assisted extraction Microwave-assisted extraction (MAE) is considered as the most convenient, reliable, and rapid method of obtaining biologically active compounds from citrus wastes using nominal amounts of solvent. For the study statistical optimization tools were employed to obtain optimal parameters for maximum recovery and results were compared with UAE. At a microwave power of 152 W, 66% methanol concentration and 49 s extraction time was reported as the optimal conditions for maximum yield by MAE method. While comparing the yield of polyphenols from lemon peels by UAE and MAE, the results were satisfactory as 15.78 6 0.8 mg/g gallic acid equivalent and 15.22 6 0.88 mg/g gallic acid equivalent were obtained by MAE and UAE, respectively. Another research group evaluated the impact of MAE, UAE, HPE (high pressure extraction), and SCE (supercritical CO2 extraction) technologies for the extraction process. The conditions maintained for operation were 125 W/35 C/30 min (UAE); 50 MPa/35 C/30 min (HPE); 200 W/180 s (MAE); 10 MPa/80 C (SCE). It has been observed that under these conditions the antioxidant activity was not optimum. The highest antioxidant activity was observed for MAE and HPE at 300 W/100 MPa. Despite its “green” nature, SCE is not recommended as an effective process for bioactive compound extraction. As subcritical CO2 is nonpolar in nature the yield is very low in comparison to MAE technology (Putnik et al., 2017).

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7.3.2

151

Recovery of essential oil

Essential oils are naturally outsourced, aromatic, complex, plant secondary metabolites. The discovery of these compounds was first attempted via steam- or hydrodistillation in the Middle Ages by Arabic individuals. These oils gained popularity for their role as antiinflammatory, antimicrobial, and analgesic agents. They are mostly volatile, lipid-soluble compounds with density less than water. Almost every organ of plants including leaves, seeds, flowers, buds, stem, fruits, stem, bark, and more specifically secretory cells, grandular trichomes, and epidermal cells synthesize essential oils in the form of metabolites. At present B3000 essential oils have been identified, out of which 300 have gained importance due to their commercial application in the cosmetic, food, sanitary, perfume, and pharmaceutical industries. In this context citrus fruits are also rich in essential oils, stored mostly in oil glands or oil sacs (diameter of 0.4
0.6 mm) located at irregular pits of flavedo, positioned in the outer skin of the fruit (Tranchida et al., 2011; Mustafa, 2015; Putnik et al., 2017). Therefore waste residues of the citrus fruit processing industry could be an ideal source for the extraction of these oils. It has been estimated that 5436 kg of oil can be extracted from 1000 kg of orange peel, where 90% of the composition consists of a cyclic terpene named D-limonene. While considering the economics of the process, the extraction of essential oil from citrus peel is a viable process because of the high value of the by-product. But proper extraction of the oil depends mostly on the extraction process, which in turn defines the purity, amount, and cost of the oil (Mamma and Christakopoulos, 2014).

7.3.2.1 Steam stripping and distillation This process is one of the very first methods used for extracting oils from plants, as it is very effective in removing oil from the activated sludge of the citrus mill. Distillation is still considered as one of the most promising and economically viable techniques in many countries, due to its better yield in comparison to other physical techniques. Citrus fruit peels are exposed to the presence of boiling steam or water, and essential oils are released by evaporation. The principle of the process is that the ambient and vapor pressure is equal at constant boiling temperature. As a result the components of the oil evaporate with water whose boiling point is in the range of 200 C
300 C. Thereafter the essential oils and steam vapors get condensed and collected in a vessel called a “Florentine flask.” Recovery of the essential oil is easy, since essential oil floats on the surface, being lighter than water. Efficiency of the process is determined by four main criteria: 1. 2. 3. 4.

duration of distillation time temperature pressure quality of the starting material

Since in this process high temperature is applied, chemical modification of the components of essential oil may occur, which in turn compromises with the quality of the essential oil (Chemat, 2010).

7.3.2.2 Expression or cold-pressing The technique uses the mechanical laceration of the epidermis and cuticle with a needle, followed by the creation of a pressure tension on the peel for the exterior movement of the oil from the inner surface. The oil is carried by a stream of water, obtaining a watery emulsion. From the emulsion the oil is separated by centrifugation. In these techniques the immediate processing of the citrus biomass is imperative prior to the commencement of the changes in chemical composition. It has been reported that D-limonene gets converted to α-terpinol due to the activities of the microflora present within the citrus biomass. Therefore immediate pressing and finer sanitation of the pressed oil is an utmost prerequisite of the cold-pressing process.

7.3.2.3 Supercritical fluid extraction The technique was invented back in the 1970s and is mostly employed for the extraction of low-quantity, high-value products. In this technique compressed CO2 gas at a temperature of 30 C
40 C and a pressure of 300 MPa is used in the recovery process. There are many advantages of this process including: 1. minimum consumption of solvents 2. rapid extraction process

152

Valorization of Fruit Processing By-products

3. highly selective 4. gas used is nonflammable and easily available, whereas the main lacunae involves high establishment costs and difficulty in continuous extractions

7.3.2.4 Subcritical water extraction The process proceeds as its name would suggest with water playing the role of an extractant. Temperature and pressure are two crucial factors in this technique. The temperature is maintained in-between 100 C and 374 C and pressure at B22.4 MPa, in order to maintain water in its liquid state. The unique property of this technique, is its application for low molecular weight compounds. Nutraceuticals from solid samples like citrus fruits pomace can be isolated by this technology (Gamiz-Gracia and de Castro, 2000; Carr et al., 2011).

7.3.2.5 Instantaneous controlled pressure drop This technique is one of the most popular techniques for the extraction of essential oil which was developed and patented by Allaf et al. (1998). The process mainly proceeds by enforcing the plant material into a rapid transition phase of high steam pressure to a vacuum. It is highly effective in comparison to classical techniques and it does not require any solvent or further distillation. “Flash evaporation” of the bulk water not only improves diffusivity and accessibility of the oil but also prevents thermal degradation of the components that are present in the oil.

7.3.2.6 Microwave extraction This technique is one of the most advanced methods invented, and it is well described and practiced to date. The advantages of the procedure are less extraction time, significant increased yield, and improved quality and purity of the product. Microwave steam diffusion is another innovation in the extraction of essential oils. In particular, microwave heating in the presence of saturated steam is used for releasing the trapped oils from the inner zone to the outer zone. In 2008 researchers at the Laboratory of Green Extractions, Universite d’ Avignon, France discovered solvent-free microwave-based technology for the extraction of essential oils as well as colors and antioxidants. The process is an amalgamation of microwave heating and gravity of Earth maintained at an atmospheric pressure. Here, the sample is placed (in the absence of water or solvent) within the microwave. An increase in temperature causes the internal moisture or water content present within the plant material to expand, leading to the rupture of oleiferous glands and receptacles. The essential oil and the internal water content get secreted by the action of the microwave. The process has been successfully applied for the extraction of essential oils from citrus peel by Bousbia et al. (2009). In 1994 Archimex patented a technology elaborated as vacuum microwave hydrodistillation. This technique is based on two basic principles, where a sequential vacuum is merged with a microwave. Initially, to refresh the dry plant material, substrates have been kept in a microwave cavity with water. Thereafter the material is exposed to microwave radiation to separate the components. The water
volatile oil mixture, being azeotropic in nature, is evaporized by reducing the pressure to 100
200 mbar. To increase the essential oil content the process is repeated so as to render absolute extraction from the source (Mamma and Christakopoulos, 2014).

7.3.3

Recovery of energy

Inevitable depletion of fossil fuel
derived fuels has been the force driving the worldwide development of the biofuel industries. With the birth of the food versus fuel controversy, second-generation biofuel production from agricultural, industrial, and other lignocellulosic wastes came into the picture (Kumar and Banerjee, 2018a; Sherpa et al., 2018; Rajak et al., 2018). Due to the presence of considerably high organic matter residues, it seems to be a promising approach to use processed citrus waste as a substrate to overcome the mitigating energy availability. The general pathway of diversified energy production from citrus waste has been depicted in Fig. 7.5. Details of the energy production are discussed below.

7.3.3.1 Bioethanol The suitability of citrus waste for bioethanol production lies in the presence of soluble and insoluble sugars. During the conversion of citrus waste to ethanol, there are primarily three checkpoints which determine the efficiency and yield of the conversion process: pretreatment, hydrolysis, and fermentation.

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153

FIGURE 7.5 Pathway of different energy production from citrus waste.

Pretreatment is carried out to enhance the vulnerability of cellulosic biomass for the action of polysaccharidedegrading enzymes (John et al., 2017). In the case of citrus waste, the necessity of pretreatment depends on the removal of limonene and pectin. Ordinarily, the most suitable methods of pretreatment are considered to be physically, thermally, and chemically assisted steps (John et al., 2017). In postprimary treatment of citrus waste, the vulnerable and accessible polysaccharide is converted into simple sugars, which is known as hydrolysis/saccharification. The most commonly used methods are enzyme- and chemical-mediated hydrolysis. Due to a number of constraints associated with acid hydrolysis, such as neutralization, and additional steps, including inhibitor removal, enzymatic saccharification is preferred for the hydrolysis of waste as it is performed under mild conditions of pressure and temperature (Althuri et al., 2017a; Banerjee et al., 2017). In the last stage the fermentation of the five or six carbon sugars, obtained from the saccharification process, is carried out to produce ethanol. Saccharification and fermentation can be performed separately or simultaneously, referred to as separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF), respectively. SHF allows the optimization of the hydrolysis and fermentation individually and hence promises better productivity, although it may lead to the inhibition of hydrolytic enzymes by hydrolysis products (Silverstein et al., 2007). Mandarin peel under SSF and SHF could yield 60 and 50 L of ethanol/1000 kg of peel, respectively (Boluda-Aguilar et al., 2010); SHF produced a higher amount of pulp pellet at the end which indicated the inhibition of enzymatic hydrolysis by glucose. One of the major bottlenecks in the conversion of waste to fuel is the limited availability of the strains for the fermentation (Althuri et al., 2017b; Avanthi et al., 2017). The inability of Saccharomyces cerevisiae and other bacterial strains to ferment pentose remains a roadblock for the efficient conversion of citrus waste into ethanol. Some yeast species such as Pichia stipitis, Candida shehatae, Kluyveromyces marxianus, and Pachysolentanno philius are efficient in utilizing pentoses, which can be used to coferment along with S. cerevisiae for complete ethanol fermentation. In SSF more than one species can be utilized for hydrolysis and fermentation which is often referred as coculturing. During citrus waste fermentation, Candida and Saccharomyces species were employed and it showed better productivity than a monoculture medium (John et al., 2017). Other than yeast thermophilic anaerobic bacterial species can also be used for the fermentation of the hydrolyzed products to produce fuel. Coculturing of Clostridium thermocellum and Clostridium thermohydrosulfuricum leads to ethanol production (Ng et al., 1981). Zymomonas mobilis has also vouched to be a potential ethanol-producing bacteria owing to its faster growth rate, high sugar uptake, increased tolerance to ethanol up to 16% (v/v), and ability to ferment under low/no oxygen conditions (Yang et al., 2016). Comprehensive details of ethanol production from citrus waste along with their pretreatment and fermentation processes are shown in Table 7.2.

154

Valorization of Fruit Processing By-products

TABLE 7.2 Ethanol yield using different citrus waste. Waste type

Pretreatment process

Fermentation process

Microorganism

Ethanol yield

Orange peel

Milling

SHF

E. coli

4.7 g/L

Citrus peel waste

Steam explosion

SSF

S. cerevisiae

3.96% (w/v)

Orange

Autohydrolysis

SHF

C. parapsilosis

4.3% (w/v)

Orange

Autohydrolysis

SHF

S. cerevisiae 1 Candida parapsilosis

5.4% (w/v)

Valencia orange

Steam explosion

SSF

S. cerevisiae

4.05% (w/v)

Orange

Acid 1 steam explosion

SHF

S. cerevisiae

0.495 g/g

Mandarin

Popping

SHEF

S. cerevisiae

46.2% (w/v)

Lemon peel

Steam explosion

SSF

S. cerevisiae

67.8 g/1000 kg

Orange

Steam explosion

SHF

C. parapsilosis

20.2% (w/v)

Mandarin

Steam explosion

SSF

S. cerevisiae

59.3% (w/v)

Orange

Steam explosion

SSF

Kluyveromyces marxianus

3.45% (w/v)

Source: Data has been taken from Satari, B., Karimi, K., 2018. Citrus processing wastes: environmental impacts, recent advances, and future perspectives in total valorization. Resour. Conserv. Recycl. 129, 153
167; John, I., Muthukumar, K., Arunagiri, A., 2017. A review on the potential of citrus waste for Dlimonene, pectin, and bioethanol production. Int. J. Green Energy 14(7), 599
612; Santi, G., Crognale, S., D’Annibale, A., Petruccioli, M., Ruzzi, M., Valentini, R., et al., 2014. Orange peel pretreatment in a novel lab-scale direct steam-injection apparatus for ethanol production. Biomass Bioenergy 61, 146
156; Choi, I.S., Kim, J.H., Wi, S.G., Kim, K.H., Bae, H.J., 2013. Bioethanol production from mandarin (Citrus unshiu) peel waste using popping pretreatment. Appl. Energy 102, 204
210; Boluda-Aguilar, M., Lo´pez-Go´mez, A., 2013. Production of bioethanol by fermentation of lemon (Citrus limon L.) peel wastes pretreated with steam explosion. Ind. Crop. Prod. 41, 188
197; Tsukamoto, J., Dura´n, N., Tasic, L., 2013. Nanocellulose and bioethanol production from orange waste using isolated microorganisms. J. Braz. Chem. Soc. 24(9), 1537
1543; Boluda-Aguilar, M., Garcı´a-Vidal, L., del Pilar Gonza´lez-Castan˜eda, F., Lo´pez-Go´mez, A., 2010. Mandarin peel wastes pretreatment with steam explosion for bioethanol production. Bioresour. Technol. 101(10), 3506
3513; Widmer, W.W., Narciso, J.A., Grohmann, K., Wilkins, M.R., 2009. Simultaneous saccharification and fermentation of orange processing waste to ethanol using Kluyveromyces marxianus. Biol. Eng. Trans. 2(1), 17
29 (Satari and Karimi, 2018; John et al., 2017; Santi et al., 2014; Choi et al., 2013; Boluda-Aguilar and Lo´pez-Go´mez, 2013; Tsukamoto et al., 2013; Boluda-Aguilar et al., 2010; Widmer et al., 2009).

7.3.3.2 Biodiesel Fatty acid profiles of vegetable oils, nonedible oils, tree-based oils and animal fats are considered as potential feedstocks for biodiesel production (Kumar and Banerjee, 2018b). Fatty acid composition of citrus waste, consisting of palmitic, oleic, and linoleic acid showed similarity to other biodiesel-producing substrates like palm, canola, and soybean oils (Reazai et al., 2014). One of the major drawbacks associated with the utilization of these citrus oils is the high acid value which is the consequence of the huge amount of free fatty acids (FFAs) and cannot be transformed into biodiesel in the presence of alkali catalysts (Canakci and Van Gerpen, 2001). Thus this fact raises the necessity of an additional pretreatment step in which FFAs are treated with methanol in the presence of an acid catalyst (Javidialesaadi and Raeissi, 2013) to convert both FFA and oil into biodiesel. But the reaction rate has been observed to be very low with an insignificant yield. Another means to circumvent the predicament is to utilize two-step transesterification where the acid treatment of the high FFA-containing oil is followed by alkali-catalyzed transesterification (Chai et al., 2014). Details of biodiesel yields using different citrus oils and their characteristics are given in Table 7.3.

7.3.3.3 Biohydrogen The operation of an anaerobic reactor depends largely on the physicochemical characteristics of the citrus waste, such as volatile solid content (VS), moisture content, biodegradability, COD, C/N ratio, carbohydrate, and fat composition. Hydrogen production from hydrocarbon-containing wastes has been reported from anaerobes, such as Clostridium butyricum, Clostridium thermolacticum, and Enterobacter cloacea. An aerobic consortium has also been utilized which involves Aeromonas, Pseudomonas, and Vibrio species (Kapdan and Kargi, 2006). Citrus waste effluents from the fruits processing industries have been found to contain high amounts of organic residues and nutrients which facilitate biohydrogen generation through dark fermentation (Torquato et al., 2017). Dark fermentation, carried out by anaerobes, utilizes the hydrogen-containing organic substrates. Hydrogen is oxidized by microbes to generate electrons which further reduce protons to yield hydrogen molecules (Łukajtis et al., 2018). Apart from effluent, anaerobic digestion of solid citrus waste, such as orange and grape waste, generates 400 mL/g VS and 500 mL/g VS biohydrogen

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155

TABLE 7.3 Biodiesel yields from citrus oils and their characteristics. Waste type

Viscosity (mm2/s)

Density (kg/m3)

Pour point

Flash point

Yield (oil content) (%)

Citrus limetta

36.2

924




164

92 (ester yield)

Citrus sinensis

2.1

825







93

Tangerine seed

37.3

568

215




25.8

Citrus reticulata seeds

4.17

882

8.00

164

28.5

Grape seed oil diesel

4.80

890

222




30.4

Orange seed oil diesel

5.60

892

225




35.2

Source: Data has been taken from Musthafa, M.M., 2016. Production of biodiesel from Citrus limetta seed oil. Energ. Source A 38(20), 2994
3000; Bull, O. S., Obunwo, C.C., 2014. Biodiesel production from oil of orange (Citrus sinensis) peels as feedstock. J. Appl. Sci. Environ. Manag. 18(3), 371
374; Agarry, S.E., Aremu, M.O., Ajani, A.O., Aworanti, O.A., 2013. Alkali-catalysed production of biodiesel fuel from Nigerian citrus seeds oil. Int. J. Eng. Sci. Technol. 5(9), 1682
1687; Rashid, U., Ibrahim, M., Yasin, S., Yunus, R., Taufiq-Yap, Y.H., Knothe, G., 2013. Biodiesel from Citrus reticulata (mandarin orange) seed oil, a potential non-food feedstock. Ind. Crop Prod. 45, 355
359 (Musthafa, 2016; Bull and Obunwo, 2014; Agarry et al., 2013; Rashid et al., 2013; Agarry et al., 2013).

(Akinbomi and Taherzadeh, 2015). Waste generated from citrus processing industries which generally includes raw wastewater and citrus vinnase is anaerobically digested in batch fermenters and yields 2.0 and 14.2 mmol H2/g COD influent for citrus vinnase and raw wastewater, respectively (Torquato et al., 2017).

7.3.3.4 Biogas Biogas production from citrus waste involves the anaerobic digestion of the organic matter by different groups of facultative and obligatory anaerobic microorganisms. Anaerobic digestion includes the steps hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Hydrolytic bacteria (Group I organisms), acetogenic bacteria (Group II organisms, Clostridium, Actionomycetes, Lactobacillus, etc.) and methanogens (Group III organisms, Methanobacterium, Methanococcus, and Methanobacillus) are the key players of biogas production (Molino et al., 2013; Bhattacharyya and Banerjee, 2007). The characterization of the citrus waste reveals the high organic matter, for example, carbohydrate present in its cell wall and significantly lower amounts of the lignin. It has been observed that ethanol from the citrus waste could produce approximately 300 kWh/ton of waste which is approximately half of the energy yield generated by methane, which is around 700 kWh/ton (Ruiz and Flotats, 2016). The biogas synthesizing procedure is influenced by a number of parameters, which include temperature, organic loading rate or solid retention time, C/N ratio, and volatile fatty acids accumulation. Optimum conditions for biogas production have been illustrated in Table 7.4. There are principally two issues associated with the utilization of the citrus waste as a substrate for anaerobic digestion, which are rapid acidification and inhibition of the microbial activity by limonene. Rapid acidification is fixed by optimizing the conditions for the individual groups in a two-stage digester. Steam explosion has been defined as an effective treatment method to remove limonene. The details of limonene recovery have been explored in the previous section. Limonene removal using membranes was carried out for effective digestion and the observed methane yield was 0.25
0.38 Nm3/kg VS (Wikandari et al., 2014). Limonene can also be extracted using solvents, such as hexane, which produces a methane yield of 0.217 Nm3/kg VS (Wikandari et al., 2014). Similarly a methane yield of 350 L/kg VS was reported from orange peel waste (Ruiz and Flotats, 2016). Wastewater, from citrus processing industries, was treated in a leach-bed reactor and yielded 2.1 Nm3 of biogas/m3 of wastewater (Koppar and Pullammanappallil, 2013). In anaerobic digestion cow dung, dairy manure, wastewater digested sludge, etc., nonavailability or availability in insufficient quantities of the inoculum becomes a hindrance in commercial biogas production. Utilization of mixed anaerobic consortia may be good alternatives to traditional inoculum in commercial biogas production (Jacob and Banerjee, 2016a).

7.3.3.5 Biofertilizer Organic fertilizers using citrus waste bear the potential to enrich soil quality via the addition of nutrient components and by maintaining pH, thus enriching the soil with beneficial microbes. Microbial action in turn digests complex

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TABLE 7.4 Optimum conditions for biogas production. Parameter

Best condition for biogas production

Temperature

Mesophilic (30 C
40 C) Thermophilic (50 C
60 C)

pH

6
7

Retention time

20
50 days

Organic loading rate

0.5
1.5 kg/VS/m3/day

C/N ratio

30
50:1

Acetic acid

,1000 mg/L (pH 7)

Butyric acid

,50 mg/L (pH 7)

NH3

80 mg/L

Source: Data has been taken from Bhattacharyya, B.C., Banerjee, R., 2007. Environmental Biotechnology. Oxford University Press, New Delhi; Wikandari, R., Millati, R., Cahyanto, M.N., Taherzadeh, M.J., 2014. Biogas production from Citrus waste by membrane bioreactor. Membranes 4, 596
607; Deublein, D., Steinhauser, A., 2008. Biogas from Waste and Renewable Resources. Wiley-VCH, Weinheim; Sung, S., Liu, T., 2003. Ammonia inhibition on thermophilic anaerobic digestion. Chemosphere 53(1), 43
52 (Bhattacharyya and Banerjee, 2007; Wikandari et al., 2014; Deublein and Steinhauser, 2008; Sung and Liu, 2003).

biomolecules into simpler ones, which may allow easier uptake by plants. Guerrero et al. (1995) reported faster growth of lettuce while using orange pulp and peel as fertilizer compared to the control. Dry orange waste exhibits the same effects as mineral fertilizers and has been associated with positive effects on soil (Tuttobene et al., 2009). In Valencia orange production utilization of organic fertilization with industrial orange wastes improved the nutritional status, fruit set, and yield of fruits (Maksoud et al., 2015). Soil to soil technology claims to use the natural, unutilized resources to produce fuel where by-products can be converted into fertilizers. The residual citrus waste after bioethanol or biogas production can be further valorized to biomanure as the solid residue. Nutrient-enriching microorganisms like Nostoc muscorum, Fischerella muscicola, Anabaena variabilis, Aulosira fertilissima, Cylindrospermum muscicola, Azospirillium lipoferum, and Azotobacter chroococcum facilitate in the enrichment of nitrogen (N), phosphorous (P), and potassium (K) composition in biomanure with the desired ratio. The utmost important of this enrichment lies in the production of biomanure with customized NPK ratios for any specific crop production, since NPK ratios for different crops like rice, potato, sorghum, cotton, and wheat vary from 4:2:1 to 4:2:2. These enriched biomanure residues act as excellent sources of essential nutrients for plant growth and humus development (Jacob and Banerjee, 2016b; Chintagunta et al., 2015; Bhattacharyya and Banerjee, 2007). Hence citrus waste from ethanol or biogas manufacturing units can be applied to the soil for better crop yield upon the characterization of N, P, K, other nutrients, and organic matter content.

7.3.3.6 Biorefinery—integrative approach to maximize waste valorization With an enormous evolution in the waste utilization technology, there has been an assurance of maximum waste utilization. But there is still a significant proportion of the undigested, yet utilizable feedstock left in the digestate. To overcome this predicament regarding the efficient utilization of the waste, an integrative biorefinery approach has been defined where the digestate from the anaerobic digestion and aerobic fermentation is further converted to a valuable product (Alrefai et al., 2017). Stillage, solid residue generated after fermentation, has significantly higher COD values which renders it a potential substrate for biogas production. It has been strongly anticipated that 50% of the stillage can be transformed into ethanol (Wilkie et al., 2000). Starch-based stillage has been evaluated by Eskicioglu et al. (2011) for anaerobic potential and has been found to produce 50 L methane/kg of the stillage in mesophilic conditions. The residues generated after biogas production can be utilized as valuable organic fertilizer (Lukehurst et al., 2010). Cumulative energy recovery can be expected to be higher for the integrative approach than the individual processes along with efficient waste utilization. From Fig. 7.6 it seems apparent that energy recovery from the citrus waste forms an interconnected network in which each step can be further forwarded for by-product conversion into value-added products. Waste segregation is ordinarily followed by oil recovery or nutrients removal and consequently solid residues are utilized for biofuel production. However, segregated waste can be directly utilized for bioenergy generation with eventual use as a biofertilizer. The waste transformation into the biofertilizers

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FIGURE 7.6 A schematic representation toward the integrated biorefinery approach from citrus fruit waste.

throws light on the very idea of the circular economy where waste originating from the citrus fruits leads to the production of biofertilizers which are applied for crop yield enhancement.

7.4 7.4.1

Other value-added products Production of enzymes

From the industrial point of view, enzymes have immense prominence for their substrate specificity, high activity, biodegradability, mild reaction conditions, high yield, low waste production, and turnover number, recyclable, low-cost, and environment-friendly properties. For enzyme production about 30% of the cost depends on the raw substrate. The food processing industry generates profuse volumes of wastes which can be used as raw materials for enzyme production. Nowadays in order to minimize enzyme production costs and reduce resource depletion the scientific community is searching for feasible alternative sources (Dash et al., 2016; Ravindran and Jaiswal, 2016a). For enzyme production the utilization of low-cost raw materials has been extensively explored. The search for new substrates for cost minimization is also an ongoing issue. The utilization of agroindustrial waste, as a low-cost raw material has immense advantages from production and environmental points of view. When considering agricultural waste for enzyme production, different residues like stem, stalk, leaves, and seed pod of crop have been used. On the other hand, from the processing steps different crop residues like husk, bran, seed, roots, bagasse, and molasses have also been explored. From the industrial residue peel from fruits and vegetables, ground nut cake, soybean cake, and coconut oil cake were also used (Sadh et al., 2018). Apart from the carbohydrate content, the presence of nutrients in food processing waste makes them more favorable for microbial growth, which facilitates in the replacement of conventional growth media. Types of enzyme production may differ with the disparity of the raw material and microbial strains involved. The following subsection deals with the production of different enzymes utilizing citrus fruit waste.

7.4.1.1 Pectinases Pectinases hold a special position in the industrial sector, as they were one of the first few groups of enzymes used at a commercial level. They have a wide spectrum of applications starting from the wine industry to the pulp-processing industry. These groups of enzymes bear the potential to hydrolyze huge pectic polysaccharides into monomeric forms. Broadly, they are classified as depolymerizing (e.g., galacturonase, pectin lyase) and demethoxylating (e.g., pectin esterase) enzymes. These enzymes are mostly used for the extraction of pulp and juices from a variety of fruits. But

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cost-effective production of these enzymes at an industrial scale is a challenge faced by scientists, researchers, and industrialists. Systematic use of citrus waste could be smart choice to serve this purpose. At the same time the selection of a robust microbial system is very important, as microbes play crucial roles in the production of enzymes (Swain et al., 2011). Mrudula and Anitharaj (2011) portrayed the production of pectinase using different waste biomass using Apergillus niger under solid-state fermentation (SSF). From their studies, they concluded that orange peel was best suited for production with an enzyme titer of 1224 U/g DMS (dry matter substrate). Another study by Sandhya and Kurup (2013) described the screening of Penicillium citrinum from rotten fruits and vegetables and its application in polygalacturonase production using orange peel as the substrate. The enzyme titer was 287.22 (U/g) DMS when using orange peel as the sole carbon source. It has been observed that orange peel in combination with basal medium have inducing effects on polygalacturonase production. The induction effects of the system enhanced polygalacturonase productivity and its specific activity to 166% in comparison to a synthetic pectin inducer. The outcome of such studies was promising and encouraging, which thereby led to scaling-up studies of polygalacturonase from Bacillus licheniformis SHG10 (Embaby et al., 2014). Based on several research reports, the use of combinations of substrates was found to be more successful in the production of hydrolytic enzymes. A study performed by Khan et al. (2012) showed that wheat straw in combination with mosambi peel extract, lemon peel extract, and orange peel extract produced pectinase with a titer value of 5.38 IU/mL in comparison to wheat straw with mosambi peel extract having an enzyme titer of 2.12 IU/mL. Apart from the several aforementioned criteria, the rheology and viscosity of the enzyme production system play crucial roles in the design of a bioreactor during the scaling-up process. As citrus peel, irrespective of its source, is rich in pectin and it naturally gelatinizes, it is also used as a commercial gelling agent. Therefore proper biochemical characterization of the peel is one of the few prerequisites before enzyme production. Therefore proper research should be performed to optimize the system, so that the substrate should not block the bioreactor and also should not compromise with the respective enzyme titer.

7.4.1.2 Cellulases The most abundant natural compound present in the world is in the form of a polysaccharide, known as cellulose. With the growth of industrialization, the supply of fuel is unable to meet the existing demand. In this scenario the enzymatic breakage of cellulose into monomeric units and its utilization for the production of ethanol can solve the issue. Cellulase is the enzyme system with the ability to cleave the β-1,4 glucan linkages of cellulose. The role of cellulase is significant in the global market, for its application as the sole saccharifying enzyme used for cleaving the lignocellulosic biomass. But the main hindrance of biomass-based biorefineries is the high cost of cellulases (Zhang and Zhang, 2013). Cellulase is an inducible enzyme controlled by molecular switching mechanisms. Therefore external supplementation of inducers, for example, sophorose, cellobiose, and lactose, promotes the elevated production of the enzyme. The enzyme is produced by a wide spectrum of microorganisms. Proper selection of the substrate, media composition, inducer, and the microbial system will not only reduce the cost but also produce enzymes with high titer. Oberoi et al. (2010) reported that dried kinnow pulp and wheat bran in the ratio 4:1 resulted in the highest FPase activity, whereas the maximum endo-1,4-β-glucanase activity was observed when dried kinnow pulp and wheat bran was used in the ratio 3:2, using Trichoderma reesei in both cases. Omojasola and Jilani (2008) demonstrated the use of residual waste biomass of C. sinensis (sweet orange) for cellulase production by Trichoderma longibrachiatum, A. niger, and S. cerevisiae. Glucose released from carboxymethyl cellulose (CMC) by the cellulase of T. longibrachiatum, A. niger, and S. cerevisiae was 3.86, 2.96, and 2.30 mg/mL, respectively.

7.4.1.3 Amylase Enzymatic catalysis of starch by amylase is among the most important industrially applied enzyme reactions. The efficiency of amylase activity depends on the properties of starch and the methodology adopted for the gelatinization. Amylase and its related properties are defined by its specific action on amylose and amylopectin components of starch. The word amylase, derived from the Greek word “amylon” meaning starch, by itself defines its specificity of action. Amylase, also known as glucoside hydrolases, acts upon linkages present in-between glucose units of starch. Thereby knowing the industrial importance of such an enzyme, it is of the utmost importance to produce the enzyme at a very cheap cost but maintain its high activity and the other desired properties to meet the global demands.

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For large-scale production of the enzyme, several starch-rich waste biomasses have been studied. However, enzyme production using citrus waste was found to be significant and interesting. Mounaimen and Mahmoud (2015) isolated a new strain of Streptomyces sp. from the soil of Algeria which they employed for the production of amylase using orange peel as the sole source of carbon. They used Plackett
Burman design as the statistical technique and as a result they found 8.26 U/mL of enzyme to be the outcome of the experiment.

7.4.1.4 Lipases While considering lipases, an interesting result regarding the presence of lipase in the peel, core, and frit of oranges has been reported by Okino-Delgado and Fleuri (2014). The species considered for the study was C. sinensis L. Osbeck Pear variety, planted in Araraquara city, Brazil. The enzyme is biologically active in a wide range of pH of 6
7 (neutral) and 8
9 (acidic). Lipases are thermostable at 20 C
70 C. The activity assay was measured on p-NP-butyrate, pNP-laurate, and p-NP-palmitate. The activity of the crude extract from the frit showed an activity of 68.5 U/g. This result shows that normal processing of the waste can also produce valuable products without fermentation. Apart from the aforementioned enzymes, other enzymes like xylanases, phytases, invertases, and β-glucanases have been reported to be produced by different microbes from citrus wastes. And from this it is possible to portray the fact that citrus waste can be a substrate for a wide spectrum of enzymes.

7.4.2

Organic acid production

In citrus fruits the organic acids account for the second most abundant class of soluble solids. Citric acid, being the predominant part of the total organic acids present in the citrus fruits, can be extracted out from citrus peel and pith waste, while malic, tartaric, benzoic, oxalic, and succinic acids, which are found in trace amounts, cannot be extracted from citrus waste efficiently (Randhawa et al., 2014). The citrus pith and peel waste contains soluble (e.g., glucose, fructose, and sucrose) and insoluble carbohydrates (e.g., cellulose, hemicelluloses, and pectin), which make the waste a tempting feedstock for organic acid production. Extraction of organic acids from the citrus peel and pith waste has been a challenge, as in most cases the waste gets contaminated with pathogens and thus the first step involved is to eliminate the unwanted pathogens by radiation treatment (Betancurt et al., 2009). After radiation treatment, the waste is subjected to enzymatic hydrolysis followed by the subsequent biological conversion by microorganisms. Investigations have found that A. niger has the potential to assemble substantial amounts of citric acid in a sugar-based medium during the fermentation process (Vandenberghe et al., 1999). This hydrolyzed liquor from citrus waste is used to make fermentation media for A. niger for the production of citric acids. This fermentation yields 4.9 g/L citric acids on the 4th day (Rivas et al., 2008). The other prevalent method of producing citric acid from citrus waste includes SSF using dried citrus peel as substrate and A. niger as inoculum. The highest concentration of citric acid obtained by this process was measured at 170.5 mg of citric acid/g dried orange peel (Torrado et al., 2011). The obtained citric acid finds extensive applications in food, beverage, cosmetic, and pharmaceutical industries. It is also widely used in other industries like textiles and electroplating. The other organic acids found in the peel and pith waste of citrus fruits include malic, tartaric, benzoic, oxalic, and succinic acids (Ikotun et al., 1988). The oxalic acid present in the peel of the citrus fruit is in the form of insoluble calcium oxalate. So, the organic acids from the citrus waste are obtained in the form of citric acid. Thus the production of citric acid has potential application in the flavoring of fruit beverages.

7.4.3

Dietary fibers production

In recent years dietary fiber (DF) has attracted a great deal of attention from research in the food industries due to its immense health benefits in the health care sector (Wang et al., 2015). In comparison to other alternative sources of DF like mango peel, guava peel, apple pomace, and grape skin, fibers from citrus fruit peels yield a high amount of soluble fibers, thereby, making citrus fruits’ waste (predominantly the peel) an inexpensive and inevitable source for obtaining DF. The content of DF varies with the varieties of citrus like lime peel 66.7%
70.4%, orange 64.3%, grapefruit peel 44.2%
62.6%, and limon peel content 60.1%
68.3% DF on the basis of dry matter (Figuerola et al., 2005). Studies say that 14.0
16.0 g of total DF can be extracted from 100 g of dried citrus peel waste (O’Shea et al., 2012). The different approaches of extraction of fibers from citrus peel include conventional solvent extraction, UAE, and MAE. The prevalent method of conventional solvent extraction of DF from peel is carried out following the enzymatic
gravimetric procedure where citrus fruits’ peels after radiation treatment were air-dried. This moisture-free

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Valorization of Fruit Processing By-products

peel powder is enzymatically hydrolyzed by heat-stable α-amylase and protease. The hydrosalate, on being centrifuged, gives a supernatant containing soluble DF and sediment containing insoluble DF. The soluble DF of the supernatant is precipitated out with 95% ethanol (Wang et al., 2015). The conventional solvent extraction procedure is time-consuming, so researchers have come up with other techniques, namely, the UAE process and MAE procedure. UAE of fibers from the citrus peel requires the dried and grounded peel powder to be mixed with sodium hexametaphosphate buffers, followed by ultrasonic processing (Keke et al., 2014). In the MAE method the process time and energy consumption are reduced by 92% and 78%, respectively, while the yield of total DF is close to 0.6 kg/kg dried peel with a ratio of soluble DF:insoluble DF of 1:1 (Talens et al., 2017). The DF so obtained can find its application in flour products like biscuits, noodles, pasta, etc., where cookies, biscuits, and other food stuffs are being loaded with DF for the betterment of human health. Meat products, dairy products, etc. can be carefully fortified with DF. The stability of the food can be improved by adding DF into beverages. For designer food formulations DF can be used as an additive agent. Thus valorizing citrus fruit waste for the inexpensive extraction of DF will find numerous commercial applications in a variety of industries.

7.4.4

Production of single cell protein

Single cell protein (SCP) refers to dead and dry cells of microorganisms like yeast, bacteria, fungi, and algae. These SCPs serve as a food or feed supplement and can be an alternative to conventional protein sources. SCP includes a high content of protein with all essential amino acids. Microorganisms serve as excellent SCP due to their rapid growth and ability to utilize agroindustrial wastes as a carbon source. In this scenario the bioconversion of fruit wastes into SCP presents an upcoming technology to solve the worldwide protein scarcity. On the other hand, the utilization of waste materials facilitates the economic production of high-concentration protein sources and the mitigation of pollution burdens by using bioreactors utilizing hardly any land space (Bajpai, 2017). The main barrier in SCP production from citrus wastes is the low nitrogen content. However, early research has already removed this barrier by trapping ammonia in fermented citrus waste. Ammonical nitrogen content was increased by 164-fold in fermented citrus biomass, and thus this increase in nitrogen content facilitated protein formation (Taiwo et al., 1995). In Scerra et al. (1999) increased the nutritional value of citrus waste by SCP through SSF. Slurry-state flask cultivation of A. niger and Trichoderma viride showed SCP production using citrus pulp, after juice extraction, and T. viride (31.9%) showed greater nitrogen content than A. niger (25.6%) (De Gregorio et al., 2002). In another study A. niger and S. cerevisiae were used for SCP production by SSF and submerged fermentation, respectively (Azam et al., 2014). In a recent study Rhodococcus opacus (PD 630 and DSM 1069) was used for the production of SCP utilizing orange waste and lemon waste effluent as low-cost carbon sources. Protein content derived from lemon waste and orange waste using PD 630 strain were 52.1% and 56.9%, respectively, whereas 45.8% and 42.2% protein were obtained using DSM 1069 strain from lemon waste and orange waste, respectively (Mahan et al., 2018).

7.4.5

Candy preparation

The physiological and phytochemical constituents of citrus peel wastes have been well discussed in the previous sections. Nonetheless, it is worth mentioning that the peel of any citrus fruit is more nutritious than the fleshy fruit. Therefore proper processing of these peels in the form of candy, jam, steamed puddings, sweet breads, cookies, and cakes not only enriches the nutritional quotient of any product but also reduces the addition of chemical and artificial additives. The application of such processes not only reduces the waste burden of the citrus fruits processing industry but also promotes the systematic usage of natural products in food industries. Candy making mostly proceeds by impregnating sugar syrup with citrus peel, followed by the draining of excess syrup. Thereafter the sugar-coated peels were dried at low temperatures in the oven or through vacuum drying, in order to retain their shelf life for prolonged periods. The initial processing technique defines the nutritional profile of the finished product. Verma et al. (2006) reported that citrus peel of Darunj (C. medica), popularly known as Gouda Khatta, can be used in making candy. The research group used two techniques, namely slow-set technique and fast-set technique, for the preparation of candy. While comparing the chemical attributes, the moisture and total sugar content were better in the slow-set technique, whereas reducing sugar and acidity were better in the fast-set technique. However, the vitamin C content was the same for both the techniques. The drying technique also plays a crucial role in the candy making process. The reason is that it is not only necessary to reduce the moisture content of the product but also to retain the natural color, flavor, and bioactive constituents of the finished candies. Sidhu et al. (2013) reported on the application of osmotic dehydration for the preparation of

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Kinnow peel candy. The candy was packed in high density polyethylene (HDPE) bags under refrigerated conditions for 60 days. Ascorbic acid, naringin, and limonin contents were found to decrease upon storage for the aforementioned conditions. Osmotic dehydration highly inhibits the growth of microorganisms belonging to the genera Escherichia, Staphylococcus, and Salmonella. Appropriate techniques can balance the nutritional profile and shelf life of the product.

7.5

Bioeconomy concept in citrus waste valorization

Bioeconomy, the renewable part of the circular economy concept, promotes revenue generation from bio-based industry. The emerging “bioeconomy” is “a new concept coined by the European Commission in 2012 to address the possibilities of the conversion of renewable biological resources into economically viable products and bioenergy” (Ravindran and Jaiswal, 2016b). The main principles of circular economy are harmonizing the bioeconomy and encouraging the recycling and reuse of material, which promotes the reutilization of available resources and thus shrinks the production of waste (Maina et al., 2017). It also promotes carbon sequestration in the biomaterial which is further recycled back as a carbon source for plants. Valorization of citrus wastes has great prospects for the evolution toward the bioeconomy. How can wastes from the citrus processing industry participate in bioeconomy? The biorefinery approach for the citrus waste may be a key element for the paradigm shift toward the bioeconomy by developing a consolidated valorization approach to produce marketable intermediates and end products (Satari and Karimi, 2018). Citrus waste has been considered as a potential feedstock for bioethanol production and anaerobic digestion for energy production. Citrus waste valorization has gained further impetus through the extraction, recovery, and production of value-added products, that is, phenolics, bioactive compounds, vitamins, essential oil, organic acid, enzymes, biochemical, and fuel. Thus the secondary use of citrus waste through valorization is a strategic management policy which reduces the volume of waste and reutilizes the available resources. A proposed pathway for revenue generation from citrus processing waste is represented in Fig. 7.7. As any single technology for valorization cannot be beneficial from the economic point of view, the implementation of an integrated process for citrus waste valorization, giving multiple products, may be a promising approach.

FIGURE 7.7 A bioeconomic pathway for citrus waste valorization.

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7.6

Future scope

Despite the potential use of citrus waste, to the best of our knowledge, only one Spanish company has developed a citrus valorization plant to produce cattle feed pellets, essential oils, biofuels, and finally reuse the used water. This poor adoption of alternatives lies in the lacuna of innovative implementations, requiring structural changes to the existing building blocks. The establishment of the proper sustainable, ecofriendly, and cost-effective green route for the extraction of biochemicals, bioactive compounds, vitamins, and essential oil is required. Extensive improvement is needed in the production efficiency and process optimization of organic acids, enzymes, SCP, and production of food ingredients. The development of a consolidated bioprocess, improvement in conversion efficiency and production pathway, cost reduction, the use of engineered strains, and the prohibition of intermediate or by-product formation in bioenergy may be the future of research leading toward the bioeconomy. The improvement of process efficiency and economy for the valorization of citrus waste and its implementation in future biorefineries will be a great contribution toward sustainable societal development. The application of citrus waste as biomanure is certainly encumbered by limited knowledge and little research which can be improved by advanced research and technologies to identify effective pathways for quality improvement. For profitability analysis of a citrus biorefinery, robust research is required, considering the uncertainty associated with the market prices, the proper valorization pathway, and other value-added products (energy), etc. An integrated approach and complete product recovery will facilitate in the increase in profitability. Investigation into the attributes of consumers and stakeholders is imperative in order to create the by-product supply chains, with the aim of the implementation of bioeconomic policies. Joint ventures between various disciplines and industries, along with legislation, improved economics, and awareness, may bring new rays of hope of heading toward a more sustainable society and a bio-based economy.

7.7

Conclusion

In the nexus of energy-food-natural resources, overall environmental footprint reduction and concern for fossil fuels diminution, introduce biomass as sustainable renewable resources for biorefineries. In these circumstances wastes from the citrus processing industry has been established as a sustainable resource in biorefining and has been subjected to the recovery value-added products and also energy generation. The green extraction process of citrus wastes facilitates in the recovery of phenolic and bioactive compounds, vitamins, and essential oils, where biotechnological advancements ensure the production of enzymes, organic acids, DF, and SCP from the wastes. Energy valorization from citrus waste has also gained an impetus by producing different gaseous and liquid biofuels. An integrated approach for valorization started with the recovery of biochemicals, the production of energy, and finally with the biofertilizer which recalls the “cradle to cradle” approach with the additional benefit of revenue generation. Alternative sources of renewable resources, less energy consumption, low pollution emissions and curtailed carbon footprint, and job opportunities which stimulate rural and regional development from citrus biorefineries are the substantiation of the bio-based economy. More advancement in the process of citrus waste valorization should focus on the low environmental impact technologies with the complete valorization of citrus waste by aiming at sustainable development and the bioeconomy. Citrus waste valorization can encourage industries to generate revenue with additional profits and reduce the costs of waste disposal.

References Agarry, S.E., Aremu, M.O., Ajani, A.O., Aworanti, O.A., 2013. Alkali-catalysed production of biodiesel fuel from Nigerian citrus seeds oil. Int. J. Eng. Sci. Technol. 5 (9), 1682
1687. Akinbomi, J., Taherzadeh, M.J., 2015. Evaluation of fermentative hydrogen production from single and mixed fruit wastes. Energies 8 (5), 4253
4272. Allaf, K., Rezzoug, S.A., Cioffi, F., Contento, M.P., 1998. Processus de Traitement Thermo-Me´canique par De´tente Instantane´e Controle´e des Fruits, Jus et Peaux d’Agrumes. French patent no. 98/11105. Alrefai, R., Benyounis, K.Y., Stokes, J., 2017. Integration approach of anaerobic digestion and fermentation process towards producing biogas and bioethanol with zero waste: technical. J. Fundam. Renew. Energy 7, 243. Althuri, A., Chintagunta, A.D., Sherpa, K.C., Rajak, R.C., Kundu, D., Singh, J., et al., 2017a. In: Kuila, A., Sharma, V. (Eds.), Microbial Enzymes and Lignocellulosic Fuel Production. Scrivener Publishing LLC: Wiley, Beverly, MA, pp. 135
170.

Citrus fruits Chapter | 7

163

Althuri, A., Gujjala, L.K.S., Banerjee, R., 2017b. Partially consolidated bioprocessing of mixed lignocellulosic feedstocks for ethanol production. Bioresour. Technol. 245, 530
539. Arau´jo, K., Mahajan, D., Kerr, R., da Silva, M., 2017. Global biofuels at the crossroads: an overview of technical, policy, and investment complexities in the sustainability of biofuel development. Agriculture 7 (32), 1
22. Avanthi, A., Kumar, S., Sherpa, K.C., Banerjee, R., 2017. Bioconversion of hemicelluloses of lignocellulosic biomass to ethanol: an attempt to utilize pentose sugars. Biofuels 8 (4), 431
444. Azam, S., Khan, Z., Ahmad, B., Khan, I., Ali, J., 2014. Production of single cell protein from orange peels using Aspergillus niger and Saccharomyces cerevisiae. Global J. Biotechnol. Biochem. 9 (1), 14
18. Bajpai, P., 2017. Single Cell Protein Production From Lignocellulosic Biomass. Springer, Singapore, pp. 1
71. Banerjee, R., Chintagunta, A.D., Ray, S., 2017. A cleaner and eco-friendly bioprocess for enhancing reducing sugar production from pineapple leaf waste. J. Clean Prod. 149, 387
395. Berk, Z., 2016. Citrus Fruit Processing. Academic Press, Elsevier, London, UK, pp. 1
318. Betancurt, P., Ares, M.I., Montalba´n, A., Arcia, P., Borthagaray, M.D., Curutchet, A., et al., 2009. Effect of irradiation as quarantine treatment on citrus fruit quality. In: 2009 International Nuclear Atlantic Conference-INAC 2009, Rio de Janeiro, RJ, Brazil. Bhattacharyya, B.C., Banerjee, R., 2007. Environmental Biotechnology. Oxford University Press, New Delhi. Boluda-Aguilar, M., Garcı´a-Vidal, L., del Pilar Gonza´lez-Castan˜eda, F., Lo´pez-Go´mez, A., 2010. Mandarin peel wastes pretreatment with steam explosion for bioethanol production. Bioresour. Technol. 101 (10), 3506
3513. Boluda-Aguilar, M., Lo´pez-Go´mez, A., 2013. Production of bioethanol by fermentation of lemon (Citrus limon L.) peel wastes pretreated with steam explosion. Ind. Crop. Prod. 41, 188
197. Bousbia, N., Vian, M.A., Ferhat, M.A., Meklati, B.Y., Chemat, F., 2009. A new process for extraction of essential oil from Citrus peels: microwave hydrodiffusion and gravity. J. Food Eng. 90 (3), 409
413. Bull, O.S., Obunwo, C.C., 2014. Biodiesel production from oil of orange (Citrus sinensis) peels as feedstock. J. Appl. Sci. Environ. Manag. 18 (3), 371
374. Calabro, P.S., Folino, A., Tamburino, V., Zappia, G., Zema, D.A., Zimbone, S.M., 2017. Valorisation of citrus processing waste: a review. Sardinia 2017, Sixteenth International Waste Management and Landfill Symposium. CISA Publisher, Italy. Canakci, M., Van Gerpen, J., 2001. Biodiesel production from oils and fats with high free fatty acids. Trans. ASAE 44 (6), 1429. Carr, A.G., Mammucarib, R., Fosterb, N.R., 2011. A review of subcritical water as a solvent and its utilisation for the processing of hydrophobic organic compounds. Chem. Eng. J. 172 (1), 1
17. Chai, M., Tu, Q., Lu, M., Yang, Y.J., 2014. Esterification pretreatment of free fatty acid in biodiesel production, from laboratory to industry. Fuel Process. Technol. 125, 106
113. Chemat, F., 2010. Techniques for oil extraction. In: Sawamura, M. (Ed.), Citrus Essential Oils: Flavor and Fragrance. Wiley, Hoboken, NJ, pp. 9
36. Chintagunta, A.D., Jacob, S., Banerjee, R., 2015. Integrated bioethanol and biomanure production from potato waste. Waste Manag. 49, 320
325. Choi, I.S., Kim, J.H., Wi, S.G., Kim, K.H., Bae, H.J., 2013. Bioethanol production from mandarin (Citrus unshiu) peel waste using popping pretreatment. Appl. Energy 102, 204
210. Cristo´bal, J., Caldeira, C., Corrado, S., Sala, S., 2018. Techno-economic and profitability analysis of food waste biorefineries at European level. Bioresour. Technol. 259, 244
252. Das, M., Kundu, D., Singh, J., Rastogi, A., Mukherjee, G., Chatterjee, A., et al., 2018. Rejuvenation of metabolic cascades for controlling aging through bioactive compounds: a review. J. Nutr. Food Sci. Forecast. 1 (1), 1
6. Dash, A., Kundu, D., Das, M., Bose, D., Adak, S., Banerjee, R., 2016. Food biotechnology: a step towards improving nutritional quality of food for Asian countries. Recent Pat. Biotechnol. 10, 43
57. De Gregorio, A., Mandalari, G., Arena, N., Nucita, F., Tripodo, M.M., Lo Curto, R.B., 2002. SCP and crude pectinase production by slurry-state fermentation of lemon pulps. Bioresour. Technol. 83, 89
94. Deublein, D., Steinhauser, A., 2008. Biogas from Waste and Renewable Resources. Wiley-VCH, Weinheim. Embaby, A.M., Masoud, A.A., Marey, H.S., Shaban, N.Z., Ghonaim, T.M., 2014. Raw agroindustrial orange peel waste as a low cost effective inducer for alkaline polygalacturonase production from Bacillus licheniformis SHG10. SpringerPlus 3 (327), 1
13. Eskicioglu, C., Kennedy, K.J., Marin, J., Strehler, B., 2011. Anaerobic digestion of whole stillage from dry-grind corn ethanol plant under mesophilic and thermophilic conditions. Bioresour. Technol. 102 (2), 1079
1086. FAO, 2017. Food and Agriculture Organization of the United Nations Citrus Fruit-Fresh and Processed Statistical Bulletin 2016. Figuerola, F., Hurtado, M.L., Estevez, A.M., Chiffelle, I., Asenjo, F., 2005. Fiber concentrates from apple pomace and citrus peel as potential fiber sources for food enrichment. Food Chem. 91, 395
401. Gamiz-Gracia, L., de Castro, M.D.L., 2000. Continuous subcritical water extraction of medicinal plant essential oil: comparison with conventional techniques. Talanta 51 (6), 1179
1185. Guerrero, C.C., de Brito, J.C., Lapa, N., Oliveira, J.S., 1995. Re-use of industrial orange wastes as organic fertilizers. Bioresour. Technol. 53 (1), 43
51. IEO, 2013. International energy outlook 2013. Retrieved from ,http://www.eia.gov/forecasts/ieo/pdf/0484(2013).pdf. (accessed 08.11.18.). Ikotun, T., Faboya, O., Umoh, S.O., 1988. Oxalic acid content of healthy and infected citrus fruits in Nigeria. Mol. Nutr. Food Res. 32 (4), 335
341. Jacob, S., Banerjee, R., 2016a. Modeling and optimization of anaerobic codigestion of potato waste and aquatic weed by response surface methodology and artificial neural network coupled genetic algorithm. Bioresour. Technol. 214, 386
395.

164

Valorization of Fruit Processing By-products

Jacob, S., Banerjee, R., 2016b. Nutrient enrichment of organic manure through biotechnological means. Waste Biomass Valor. 8 (3), 645
657. Javidialesaadi, A., Raeissi, S., 2013. Biodiesel production from high free fatty acid-content oils: experimental investigation of the pretreatment step. APCBEE Proced. 5, 474
478. John, I., Muthukumar, K., Arunagiri, A., 2017. A review on the potential of citrus waste for D-limonene, pectin, and bioethanol production. Int. J. Green Energy 14 (7), 599
612. Kapdan, I.K., Kargi, F., 2006. Biohydrogen production from waste materials. Enzyme Microb. Technol. 38 (5), 569
582. Keke, C., Wei, Y., Xiaofang, Z., Xiujuan, T., Xiaoxiang, H., Jianrong, L., 2014. Ultrasound-assisted extraction of dietary fiber from Citrus Changshan-huyou peels. J. Chem. Pharm. Res. 6 (2), 312
318. Khan, A., Sahay, S., Rai, N., 2012. Production and optimization of pectinase enzyme using Aspergillus niger strains in solid state fermentation. Res. J. Biotechnol. 3 (3), 19
25. Koppar, A., Pullammanappallil, P., 2013. Anaerobic digestion of peel waste and wastewater for onsite energy generation in a citrus processing facility. Energy 60, 62
68. Kumar, S., Banerjee, R., 2018a. Enzymatic delignification and saccharification of Bambusa bambos for biobutanol production. Ind. Crop. Prod. 125 (1), 386
394. Kumar, S.P.J., Banerjee, R., 2018b. Enhanced lipid extraction from oleaginous yeast biomass using ultrasound assisted extraction: a greener and scalable process. Ultrason. Sonochem. Available from: https://doi.org/10.1016/j.ultsonch.2018.08.003. Kundu, D., Singh, J., Das, M., Rastogi, A., Banerjee, R., 2018. A sustainable process for nutrient enriched fruit juice processing: an enzymatic venture. In: Kuila, A., Sharma, V. (Eds.), Principle and Applications of Fermentation Technology. Scrivener Publishing LLC, Wiley, Beverly, MA, pp. 387
400. Kundu, D., Karmakar, S., Banerjee, R., 2019. In silico optimization of enzyme mediated debittering of Assam lemon: biochemical and sensory evaluation studies. J. Food Sci. Technol. 56 (4), 2233
2243. Londono-Londono, J., Lima, V.R., Lara, O., Gil, A., Pasa, T.B.C., Arango, G.J., et al., 2010. Clean recovery of antioxidant flavonoids from citrus peel: optimizing an aqueous ultrasound-assisted extraction method. Food Chem. 119, 81
87. Łukajtis, R., Hołowacz, I., Kucharska, K., Glinka, M., Rybarczyk, P., Przyjazny, A., et al., 2018. Hydrogen production from biomass using dark fermentation. Renew. Sust. Energy Rev. 91, 665
694. Lukehurst, C.T., Frost, P., Al Seadi, T., 2010. Utilisation of digestate from biogas plants as biofertiliser. IEA Bioenergy. 1
36. Available from: http:// task37.ieabioenergy.com/files/daten-redaktion/download/publi-task37/Digestate_Brochure_Revised_12-2010.pdf. Lv, X., Zhao, S., Ning, Z., Zeng, H., Shu, Y., Tao, O., et al., 2015. Citrus fruits as a treasure trove of active natural metabolites that potentially provide benefits for human health. Chem. Cent. J. 9 (68), 1
14. Mahan, K.M., Le, R.K., Wells Jr., T., Anderson, S., Yuan, J.S., et al., 2018. Production of single cell protein from agro-waste using Rhodococcus opacus. J. Ind. Microbiol. Biotechnol. 45, 795
801. Maina, S., Kachrimanidou, V., Koutinas, A., 2017. A roadmap towards a circular and sustainable bioeconomy through waste valorization. Curr. Opin. Green Sustain. Chem. 8, 18
23. Maksoud, M.A., El-Shamma, M.S., Saleh, A.M., Zaied, S.N., Hafez, M.O., 2015. Industrial orange wastes as organic amendments in citrus orchards. Am.-Eur. J. Agric. Environ. Sci. 15 (6), 1163
1166. Mamma, D., Christakopoulos, P., 2014. Biotransformation of citrus by-products into value added products. Waste Biomass Valor. 5, 529
549. Molino, A., Nanna, F., Ding, Y., Bikson, B., Braccio, G., 2013. Biomethane production by anaerobic digestion of organic waste. Fuel 103, 1003
1009. Mounaimen, O., Mahmoud, K., 2015. Statistical optimization of cultural conditions of anhalophilic alpha-amylase production by halophilic Streptomyces sp. grown on orange waste powder. Biocatal. Agric. Biotechnol. 4 (4), 685
693. Mrudula, S., Anitharaj, R., 2011. Pectinase production in solid state fermentation by Aspergillus niger using orange peel as substrate. Glob. J. Biotechnol. Biochem. 6 (2), 64
71. Mustafa, N.E.M., 2015. Citrus essential oils: current and prospective uses in the food industry. Recent Pat. Food Nutr. Agric. 7, 115
127. Musthafa, M.M., 2016. Production of biodiesel from Citrus limetta seed oil. Energy Sour. A 38 (20), 2994
3000. Ng, T.K., Ben-Bassat, A., Zeikus, J.G., 1981. Ethanol production by thermophilic bacteria: fermentation of cellulosic substrates by cocultures of Clostridium thermocellum and Clostridium thermohydrosulfuricum. Appl. Environ. Microbiol. 41 (6), 1337
1343. Oberoi, H.S., Chavan, Y., Bansal, S., Dhillon, G.S., 2010. Production of cellulases through solid state fermentation using kinnow pulp as a major substrate. Food Bioprocess. Technol. 3 (4), 528
538. Okino-Delgado, C.H., Fleuri, L.F., 2014. Obtaining lipases from byproducts of orange juice processing. Food Chem. 15 (163), 103
107. Omojasola, P.F., Jilani, O.P., 2008. Cellulase production by Trichoderma longi, Aspergillus niger and Saccharomyces cerevisiae cultured on waste materials from orange. Pak. J. Biol. Sci. 11, 2382
2388. O’Shea, N., Arendt, E.K., Galladher, E., 2012. Dietary fibers and phytochemical characteristics of fruit and vegetable by-products and their recent applications as novel ingredients in food products. Innov. Food Sci. Emerg. Technol. 16, 1
10. Pourbafrani, M., Forga´cs, G., Horva´th, I.S., Niklasson, C., Taherzadeh, M.J., 2010. Production of biofuels, limonene and pectin from citrus wastes. Bioresour. Technol. 101, 4246
4250. Putnik, P., Kovacevic, D.B., Jambrak, A.R., Barba, F.J., Cravotto, G., Binello, A., et al., 2017. Innovative “Green” and novel strategies for the extraction of bioactive added value compounds from citrus wastes—a review. Molecules 22 (5), 680.

Citrus fruits Chapter | 7

165

Qiao, L., Sun, Y., Chen, R., Fu, Y., Zhang, W., Li, X., et al., 2014. Sonochemical effects on 14 flavonoids common in citrus: relation to stability. PLoS One 9 (2), e87766. Rajak, R.C., Singh, A., Banerjee, R., 2018. An eco-friendly process integration for second generation bioethanol production from laccase delignified Kans grass. Energy Convers. Manag. 157, 364
371. Randhawa, M.A., Rashid, A., Saeed, M., Javed, M.S., Khan, A.A., Sajid, M.W., 2014. Characterization of organic acids in juices of some Pakistani citrus species and their retention during refrigerated storage. J. Anim. Plant Sci. 24 (1), 211
215. Rashid, U., Ibrahim, M., Yasin, S., Yunus, R., Taufiq-Yap, Y.H., Knothe, G., 2013. Biodiesel from Citrus reticulata (mandarin orange) seed oil, a potential non-food feedstock. Ind. Crop Prod. 45, 355
359. Ravindran, R., Jaiswal, A.K., 2016a. Microbial enzyme production using lignocellulosic food industry wastes as feedstock: a review. Bioengineering 3, 1
22. Ravindran, R., Jaiswal, A.K., 2016b. Exploitation of food industry waste for high-value products. Trends Biotechnol. 34, 58
69. Reazai, M., Mohammadpourfard, I., Nazmara, S., Jahanbakhsh, M., Shiri, L., 2014. Physicochemical characteristics of citrus seed oils from Kerman, Iran. J. Food Lipids 2014, 1
3. Rivas, B., Torrado, A., Torre, P., Converti, A., Dominguez, J.M., 2008. Submerged citric acid fermentation on orange peel autohydrolysate. J. Agric. Food Chem. 56, 2380
2387. Ruiz, B., Flotats, X., 2016. Effect of limonene on batch anaerobic digestion of citrus peel waste. Biochem. Eng. J. 109, 9
18. Sadh, P.K., Duhan, S., Duhan, J.S., 2018. Agroindustrial wastes and their utilization using solid state fermentation: a review. Bioresour. Bioprocess. 5 (1), 1
15. Sandhya, R., Kurup, G., 2013. Screening and isolation of pectinase from fruit and vegetable wastes and the use of orange waste as a substrate for pectinase production. Int. Res. J. Biol. Sci. 2 (9), 34
39. Santi, G., Crognale, S., D’Annibale, A., Petruccioli, M., Ruzzi, M., Valentini, R., et al., 2014. Orange peel pretreatment in a novel lab-scale direct steam-injection apparatus for ethanol production. Biomass Bioenergy 61, 146
156. Satari, B., Karimi, K., 2018. Citrus processing wastes: environmental impacts, recent advances, and future perspectives in total valorization. Resour. Conserv. Recycl. 129, 153
167. Satari, B., Palhed, J., Karimi, K., Lundin, M., Taherzadeh, M.J., Zamani, A., 2017. Process optimization for citrus waste biorefinery via simultaneous pectin extraction and pretreatment. BioResearch 12, 1706
1722. Sataria, B., Karimi, K., 2018. Citrus processing wastes: environmental impacts, recent advances, and future perspectives in total valorization. Resour. Conserv. Recycl. 129, 153
167. Scerra, V., Caridi, A., Foti, F., Sinatra, M.C., 1999. Influence of dairy Penicillium spp. on nutrient content of citrus fruit peel. Anim. Feed Sci. Technol. 78, 169
176. Sherpa, K.C., Ghangrekar, M.M., Banerjee, R., 2018. A green and sustainable approach on statistical optimization of laccase mediated delignification of sugarcane tops for enhanced saccharification. J. Environ. Manage. 217, 700
709. Sidana, J., Saini, V., Dahiya, S., Nain, P., Bala, S., 2013. A review on citrus—the boon of nature. Int. J. Pharm. Sci. Rev. Res. 18 (2), 20
27. Sidhu, N., Arora, M., Alam, M.S., 2013. Biochemical, microbial stability and sensory evaluation of osmotically dehydrated kinnow peel candy and peel powder. Int. J. Sci. Res. 5 (9), 1428
1437. Silverstein, R.A., Chen, Y., Sharma-Shivappa, R.R., Boyette, M.D., Osborne, J., 2007. A comparison of chemical pretreatment methods for improving saccharification of cotton stalks. Bioresour. Technol. 98 (16), 3000
3011. Singh, J., Kundu, D., Das, M., Banerjee, R., 2019. Enzymatic processing of juice from fruits/vegetables: an emerging trend and cutting edge research in food biotechnology. In: Kuddus, M. (Ed.), Enzymes in Food Biotechnology. Academic Press, Elsevier, pp. 419
432. Sun, Y., Liu, D., Chen, J., Ye, X., Yu, D., 2011. Effects of different factors of ultrasound treatment on the extraction yield of the all-trans-β-carotene from citrus peels. Ultrason. Sonochem. 18, 243
249. Sung, S., Liu, T., 2003. Ammonia inhibition on thermophilic anaerobic digestion. Chemosphere 53 (1), 43
52. Swain, M.R., Ray, R.C., Patra, J.K., 2011. Citric acid: microbial production and applications in food and pharmaceutical industries. In: Vargas, D.A., Medina, J.V. (Eds.), Citric Acid. Nova Science Publisher, New York, pp. 97
118. Taiwo, A.A., Adebowale, E.A., greenhalgh, J.F.D., Akinsoyinu, A.O., 1995. Techniques for trapping ammonia generated from urea treatment of barley straw. Anim. Feed Sci. Tech. 56, 133
141. Talens, C., Arboleya, J.C., Giraldez, M.C., Fito, P.J., 2017. Effect of microwave power coupled with hot air drying on process efficiency and physicchemical properties of a new dietary fiber ingredient obtained from orange peel. LWT-Food Sci. Technol. 77, 110
118. Torquato, L.D., Pachiega, R., Crespi, M.S., Nespeca, M.G., de Oliveira, J.E., Maintinguer, S.I., 2017. Potential of biohydrogen production from effluents of citrus processing industry using anaerobic bacteria from sewage sludge. Waste Manage. 59, 181
193. Torrado, A.M., Corte´s, S., Salgado, J.M., Max, B., Rodrı´guez, N., Bibbins, B.P., et al., 2011. Citric acid production from orange peel wastes by solidstate fermentation. Braz. J. Microbiol. 42, 394
409. Tranchida, P.Q., Bonaccorsi, I., Dugo, P., Mondello, L., Dugo, G., 2011. Analysis of citrus essential oils: state of the art and future perspectives. A review. Flav. Fragr. J. 27 (2), 98
123. Tsukamoto, J., Dura´n, N., Tasic, L., 2013. Nanocellulose and bioethanol production from orange waste using isolated microorganisms. J. Braz. Chem. Soc. 24 (9), 1537
1543. Tuttobene, R., Avola, G., Gresta, F., Abbate, V., 2009. Industrial orange waste as organic fertilizer in durum wheat. Agron. Sustain. Dev. 29 (4), 557
563.

166

Valorization of Fruit Processing By-products

USDA, 2018. Citrus: World Markets and Trade. United States Department of Agriculture, pp. 1
11. Vandenberghe, L.P.S., Soccol, C.R., Pandey, A., Lebeault, J.M., 1999. Microbial production of citric acid. Braz. Arch. Biol. Technol. 42 (3). Available from: https://doi.org/10.1590/S1516-89131999000300001. Vergamini, D., Cuming, D., Viaggi, D., 2015. The integrated management of food processing waste: the use of the full cost method for planning and pricing Mediterranean citrus by-products. Int. Food Agribus. Man. 18 (2), 153
172. Verma, R., Kalia, M., Sharma, H.R., 2006. Effect of method of preparation and storage on the chemical characteristics of peel candy of Darunj (Citrus medica). J. Dairying Foods Home Sci. 25 (2), 113
116. Wang, L., Xu, H., Yuan, F., Pan, Q., Fan, R., Gao, Y., 2015. Physicochemical characterization of five types of citrus dietary fibers. Biocatal. Agric. Biotechnol. 4 (2), 250
258. Widmer, W.W., Narciso, J.A., Grohmann, K., Wilkins, M.R., 2009. Simultaneous saccharification and fermentation of orange processing waste to ethanol using Kluyveromyces marxianus. Biol. Eng. Trans. 2 (1), 17
29. Wikandari, R., Millati, R., Cahyanto, M.N., Taherzadeh, M.J., 2014. Biogas production from citrus waste by membrane bioreactor. Membranes 4, 596
607. Wilkie, A.C., Riedesel, K.J., Owens, J.M., 2000. Stillage characterization and anaerobic treatment of ethanol stillage from conventional and cellulosic feedstocks. Biomass Bioenergy 19 (2), 63
102. Yang, S., Fei, Q., Zhang, Y., Contreras, L.M., Utturkar, S.M., Brown, S.D., et al., 2016. Zymomonas mobilis as a model system for production of biofuels and biochemicals. Microb. Biotechnol. 9 (6), 699
717. Zema, D.A., Calabro`, P.S., Folino, A., Tamburino, V., Zappia, G., Zimbone, S.M., 2018. Valorisation of citrus processing waste: a review. Waste Manage. 80, 252
273. Zhang, X.Z., Zhang, Y.H.P., 2013. Cellulases: characteristics, sources, production, and applications. In: Yang, S.T., El-Enshasy, H.A., Thongchul, N. (Eds.), Bioprocessing Technologies in Biorefinery for Sustainable Production of Fuels, Chemicals, and Polymers. John Wiley & Sons, Inc, Hoboken, NJ, pp. 131
146.

Further reading Tsagkari, M., Couturier, J.L., Kokossis, A., Dubois, J.L., 2016. Early-stage capital cost estimation of biorefinery processes—a comparative study of heuristic techniques. ChemSusChem 9, 2284
2297.

Chapter 8

Mango C.H. Okino-Delgado1, D.Z. Prado2, Milene Stefani Pereira2, Dafne Angela Camargo2, Meliane Akemi Koike2 and Luciana Francisco Fleuri2 1

Agronomic Engineering, University Center of Rio Preto, Sa˜o Jose´ do Rio Preto, Brazil, 2Sa˜o Paulo State University (UNESP), Institute of

Biosciences, Botucatu, Brazil

Chapter Outline 8.1 8.2 8.3 8.4

Introduction Mango waste Mango peel Mango seed

8.1

167 169 170 172

8.5 Mango waste as substrate 8.6 Prospects and conclusion References Further reading

174 177 177 181

Introduction

Annually, about 865 million tons of fruit are produced worldwide. The 10 most produced species are banana, melon, apple, grape, orange, mango, pear, pineapple, peach, and nectarine (Rabobank Food and Agribusiness, 2018; FAO, 2017). Mango is the second most produced tropical fruit; in 2016 around 45 million tons of mangoes were produced worldwide. India is the country with the highest productivity of mango, which corresponds to 50% of world mango productivity, followed by China and Thailand. However, India was the sixth largest exporter in 2017 and China the eighth, indicating that the domestic market is the main destination (FAO, 2017) (Fig. 8.1). The mango is a tree specie originated in Asia that belongs to the Anacardiaceae family, in the Mangifera genus, which comprises over 70 cataloged species. The best-known and most consumed species is Mangifera indica L.

FIGURE 8.1 World production of mango in 2016 (tonnes). Data from FAO—Food and Agriculture Organization of the United Nations, 2017. Global initiative on food loss and waste. Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00008-3 © 2020 Elsevier Inc. All rights reserved.

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Currently there are more than 1,000 different mango cultivars, which explains the diversity of colors, shapes, and sizes of commercial fruits (Berardini et al., 2005). Mango types are commercially divided by the colors of peel red and yellow. When mature the red ones remain with a reddish peel, this group includes the American varieties Haden, Tommy Atkins, Keitt, Kent, and Palmer. Red mangoes have greater acceptance in the world market, high production by area, sweet pulp ($16  Brix), and low fiber content. While yellow mangoes, such as the ones from the varieties Afonso and Totapuri, remain with a yellowish peel when mature, and have greater acceptance in the producing regions (Bally, 2006). The variety Tommy Atkins, from Florida (United States), is the most commercialized and appreciated variety worldwide. The fruits are medium to large (460 g) with thick peel and oval in shape, the fruit color is orange-yellow covered with an intense red and purple peel, the pulp is firm and juicy, and the fiber content is medium (IBRAF, 2013). Currently mango is produced in all tropical areas due to its sweetness, exotic taste, and succulence. Mango has a large number of bioactive compounds and can be considered a functional food, that is, its consumption can improve health and reduce the risks of developing chronic degenerative diseases (Matheyambath et al., 2016). It is estimated that 80% of the mango production is internationally traded in natura, but almost half of the production does not reach the final consumer. Therefore mango is among the foods with a high food loss index, since the overall food loss index (including all food from plant and animal origin) is about 33%, and the fruits and vegetables food loss index is 45% (FAO, 2018; Rabobank Food and Agribusiness, 2018). In this context, “food loss” can be defined as any food that is not consumed due to losses throughout the production chain, including agricultural production, postharvest processing, and transportation. “Food waste” refers to all material discarded or not used during food processing, and “by-products” are the products obtained directly from the food waste, that is, the products from the reuse of food waste (Okino-Delgado et al., 2018; FAO, 2017). The causes of food loss and waste are generally influenced by agricultural production, choices and standards, internal infrastructure and capacity, marketing chains and distribution channels, and consumption and food use. However, the causes may vary depending on the country and the conditions of each production process (FAO, 2017). In developing countries, which include the major mango producing and exporting countries such as India, Mexico, and Brazil, food loss occurs mainly in the early stages of the value chain. It is estimated that, in developing countries 40% food loss occur in postharvest and processing, while in industrialized countries more than 40% losses occur at the retail and consumer stages. Thus the strengthening of the supply chain by supporting farmers and investing in infrastructure, transportation, and expansion of the food and packaging industry can be efficient measures to reduce food loss (FAO, 2011). The mango maturation stage is one of the characteristics that most influences mango postharvest, directly impacting the quality and loss index (Lawson et al., 2019). The impact of the mango maturation stage can be explained by the biological functions of fruits, since during seeds development the fruit serves as a protective layer and contains a high concentration of astringent compounds, green coloration, and resistant texture. Thus the immature fruit is firm and has unattractive aroma and taste, which contribute to its storage and postharvest period (Nzikou et al., 2010). However, when the seed is fully developed the fruit also has the function of attracting dispersing agents. Mango changes to a soft and juicy texture, with intense coloring and a sweet taste and aroma (Martı´nez et al., 2012). Thus due to the loosening of structures and the production of sugar, the mature mango fruit becomes extremely susceptible to degradation, which makes postharvesting difficult and contributes to the high levels of food loss during storage and distribution of mango in natura (Arora et al., 2018). Despite the popularity of mango, only 4% of global production is marketed in the international fresh food market (Mulderji, 2019). Mangoes are fleshy fruits and consequently have a short shelf life due to high water content and nutrient concentration, which contribute to the maintenance of high metabolic and microbial activity, and fast deterioration and decomposition. Thus processes that increase shelf life are beneficial for reducing losses. In addition, although the world market is supplied throughout the year, mango is seasonal in the main exporting countries such as India, Mexico, and the Philippines, which increases food loss indices in periods of high supply. Thus processing is a solution to the surplus production and is a possibility for offering products outside seasonal time (Rabobank Food and Agribusiness, 2018; FAO, 2017; Jawad et al., 2013). Mango is still mostly consumed and commercialized in natura, however, the majority of the commercial cultivars can be used for the production of processed products such as juices, nectars, concentrates, jellies, preserves, chutneys, purees, and dehydrated products (Hui, 2007). The most used part of mango is the pulp, since it serves as a raw material for jelly, juices, nectars, and sweets. The difference between pulp and puree is the amount of fibers and consistency. Puree has fewer fibers and a softer consistency. For the production of puree and pulp it is recommended that the mangoes are fully ripe. After the harvest, fruits

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are washed and depending on the process, it may be necessary to remove the peel, before placing the fruits on a finisher. For the removal of residual parts and peels, the product passes through sieves with different “mesh” sizes. Sugar may be added to the final product until it reaches 42  Brix. The antioxidant, citric acid, is also added in order to maintain the product flavor and color. Before packing, the puree passes through a heat treatment (hot-fill at 85 C and 100 C for 45 min) to ensure increased shelf life (Narain et al., 1998). The dehydrated mango is produced with cut and sanitized ripe fruits. Osmotic dehydration can be performed by immersing mango pieces into a highly concentrated sugar syrup BRIX (70  Brix). After the immersion mangoes are sanitized with sulfite solution and vacuum-dried (2
4 mm Hg and 60oC
66oC) until 2% humidity (Narain et al., % % 1998). Mango juice and nectar are ready-to-drink beverages, which are differentiated by the content of pulp. The concentration criterion varies according to the legislation of each country or region, but the juice always has a higher concentration of pulp and less addition of other compounds. In the mango beverages production, the pulp is diluted with water with the addition of sugar and preservatives. The product also receives heat treatment, which can vary depending on the packaging (Sadiq et al., 2017). Chutney is a mango product prepared with the pulp and the addition of sugar, spice (chilies, salt, and black pepper), and citric acid (0.5%). This mixture is cooked and hot-packed at 85oC. The package is cooled before being stored % (Barta et al., 2006). Mango puree is the raw material of mango powder; its preparation may use various equipment, such as spray drying. Mango puree is mixed with glucose syrup (5%) and tricalcium phosphate (0.5%, an anticaking agent), warmed at 50oC % for 30 min, homogenized, and dehydrated until approximately 3% humidity. The final product is packaged for future commercialization. The chosen dehydration process and packaging may influence the product shelf life and physicochemical properties (Sadiq et al., 2017). In the production of canned mango, mature fruits are cut and bleached, then the cans are filled with sugar syrup (40%) and citric acid (0.3%). The cans are sealed and the thermal processing is carried out with subsequent cooling (Sadiq et al., 2017). Mango products’ consumption has been growing, following the world trend (Hui, 2007). This trend also increased the worldwide market for fruit and vegetable processing equipment, which increased to about US$250 billion in 2017, with expectations of reaching US$340 billion by 2022. Market growth is driven by the demand growth for more practical foods, the development of new postharvest technologies to increase shelf life, and an increase in the awareness of the benefits of fruits and vegetables (Markets and Markets, 2018). During mango processing, 40%
50% of the fruit mass is considered waste, and approximately 400,000 tons of waste is generated every year, which leads to expenses to ensure adequate disposal, transportation, and treatment to reduce environmental damage (Martı´nez et al., 2012; Sruamsiri and Silman, 2009; Puravankara et al., 2000). In addition, the current global economic scenario has forced fruit processing companies to increase profitability linked to sustainability. Therefore transforming waste into by-products has become vital for maintaining industrial competitiveness and longevity (Okino-Delgado et al., 2018). Each agricultural waste may have a different destination. In this sense, fruit processing stands out for the richness and diversity of the wastes’ composition. However, as described by Farnsworth et al. (2015) “to value something, you first have to know what it is,” that is, for transforming waste into by-products it is necessary to bioprospect its components. There are two ways of using food processing wastes: directly, when a biomolecule of interest is a waste component; and indirectly, when wastes are used as substrates in fermentative processes to produce a biomolecule of interest, thereby, wastes are the nutritional sources and support for a microorganism that will produce a biomolecule (Okino-Delgado et al., 2018; Fleuri, 2016). Wastes from mango processing can be used directly or indirectly for the extraction of biomolecules (Fleuri, 2016). However, before discussing the biotechnological applications of mango wastes, it is crucial to understand how wastes are generated and composed. Therefore in the next section, we describe the main wastes and by-products of mango processing obtained directly and indirectly.

8.2

Mango waste

Mango fruits are classified as fleshy drupes with very variable characteristics in relation to size, weight (few grams to approximately 2 kg), shape (reniform, ovate, oblong, rounded, and cordiform) and color (various shades of green, yellow, and red) (Nzikou et al., 2010). The fruits are consumed in all maturation phases, from green/immature (the most consumed form in Asia as salty or bittersweet products like pickles, chutney, and amchur) to completely mature

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(most appreciated by the importing markets, as pulp, puree, juices, and beverages) (Ravani and Joshi, 2013). The composition of the fruit and its wastes, may vary depending on the stage of maturation, region of cultivation, and type of cultivar (Dar et al., 2016; Jahurul et al., 2015; Ma et al., 2011). Notably studies on mango waste have grown exponentially in recent years. Currently there are 3298 scientific articles registered in Science Direct with the term “mango waste,” and 1,951 of these articles were published after 2011. In addition, there are about 6,198 registered studies that include the term “mango seed,” of which 1685 were published after 2015; 3705 studies with the term “mango peel,” 1600 with the term “mango kernel,” and 41 mentioning “mango coproduct.” These data demonstrate the current relevance of the topic, but also show the need for standardization of terms for understanding and comparing data. The ripe fruits are composed of pericarp and seed; pericarp is composed of mesocarp, exocarp, and endocarp. The mesocarp (known as pulp) is the most consumed part of the fruit and consists of 33%
85% of the fruit mass, whose percentage depends on the cultivar, maturation stage, desired final product, and type of processing. The exocarp corresponds to the peel and the endocarp (known as pit) is the woody structure that surrounds the seed. In this context, the endocarp plus the seed are also known as the kernel. In general wastes from mature mango processing can be divided into peel and seed (Okino-Delgado and Fleuri, 2016; Jahurul et al., 2015), as shown in Fig. 8.2.

8.3

Mango peel

The mango peel wastes correspond to approximately 7%
24% of the total mass of the dried fruit and are composed of proteins, soluble carbohydrates, fibers, pectic, and bioactive compounds (Sogi et al., 2015; Ajila et al., 2007). Fig. 8.3

FIGURE 8.2 Morphology of mango fruit and its industrial components (modified from Okino-Delgado and Fleuri (2016)).

FIGURE 8.3 By-products from mango peel.

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summarizes the main mango by-products that can be extracted from mango peel, that is, juice pomace, pectin, pigments, and antioxidants. These by-products can be used as food ingredients in the production of the main mango products or other food products. A percentage of the pulp and mesocarp always remains in the peel after mango processing; this fraction is known as pomace and can be extracted from peel wastes using pectinases. The extraction by-product is commercially nominated as juice from pomace. This juice has an astringent taste due to the presence of tannins and is used in the production of other processed mango products, such as mango slices (Koubala et al., 2008a; Berardini et al., 2005). The consumption of juice from pomace has also been associated with human health benefits, for promoting antilipid peroxidation and lower blood cholesterol levels, and for having anticancer properties (Hu et al., 2018). The commercialization of mango pomace as a food ingredient may become very profitable in the near future, due to changes in the consumers’ wishes to more practical, durable, and high nutritional products. The food industry also needs to establish a balance between the new market demands imposed by the market and the costs of new ingredients and the requirements of food and environmental safety. In this scenario fruit pomaces are an ideal raw material since, in general, they are low-cost by-products, rich in nutritional and bioactive compounds, and are considered safe and natural food ingredients that can receive organic certification. Therefore the growth of the fruit pomace market has been boosted in recent years, mainly because of grape pomace, which accounted for approximately 28% of the pomace market in 2017, with a compound annual growth rate forecast of 4.0% between 2018 and 2027 (Future Market Insights, 2018). Pectin is a polysaccharide that can be extracted from mango peel, as a by-product. This polysaccharide has a high diversity of applications and can be used in the food, cosmetics, and pharmaceutical industries due to its action as a stabilizer and texturizing and gelling agent. Pectin is advantageous because natural products have a better consumer acceptance in relation to synthetic additives and because it has low caloric value when compared to other thickeners such as animal fats (Anthon and Barrett, 2008; Koubala et al., 2008b). The major components of mango peel pectin are methoxyl ester and galacturonic acid (Nwanekezi et al., 1994) and the mango varieties Manila and Tommy Atkins are the most promising regarding pectin content and quality, due to the low concentrations of methoxyl (Berardini et al., 2005). Pectin extraction from the mango peel can be performed by acid treatment, followed by precipitation with organic solvents, filtration, and drying as described by Gragasin et al. (2014). In addition, the pectin extraction from the variety Totapuri for the production of puree has been improved by studies such as the one conducted by Pandit et al. (2015). The authors verified that there is an increase in pectin yield when samples were subjected to microwave and shorter extraction periods, influencing the methoxy and galacturonic acid content, and pectin viscosity. Studies such as the one from Banerjee et al. (2016) have searched for ecofriendly and safe methods for the extraction of mango peel pectin for further product consumption, such as lemon juice as an acidifying agent, which resulted in 26% (w/w) of pectin per dried peel mass. Although previous studies demonstrated that mango peel can be used for the extraction of high quality pectin, these methods are still underutilized on a commercial scale, probably due to the well-established apple and citrus peel pectin industry. However, in regions of high mango production and processing like the Asian continent, mango peel pectin can be considered a promising alternative (Sirisakulwat et al., 2008). The nutritional and functional compounds of mango peel are fibers, minerals, mono- and diterpenes, and antioxidants such as phenolic compounds, mangiferin, kaempferol, quercetin, and anthocyanins (Jahurul et al., 2015). Pigments and antioxidants can be extracted using organic solvents such as ethanol or acetone. For the extraction, peels must be ground, then extracted with an organic solvent, and decantated. The liquid phase is known as the crude extract and the solid phase can be used for the production of mango peel flour. Flour can be used as a functional ingredient in bread products such as pasta, bread, sponge cake, and biscuits, with improved rheological, physical, sensorial, and antioxidant properties (Abdul Aziz et al., 2012). The extracts may be used in the crude form or as raw material to obtain specific compounds by purification processes (Ma et al., 2011; Berardini et al., 2005). Mangiferine is a xanthone classified as a “superantioxidant” as its action is similar to natural antioxidants such as vitamin C and E. This xanthone exerts a protective function on the metabolism of mangoes against static and dynamic stresses, including pathogenic microbial flora (Asif et al., 2016). When applied to human health, mangiferine has shown nutraceutical and pharmaceutical properties against degenerative diseases, such as cardiovascular disease and cancer. Mango peel powder has a significant amount of fiber, carotenoids, minerals, and antioxidants, such as several polyphenols. The synergism between different polyphenols results in maximum antioxidant activity and its potential health benefits (Elhassaneen et al., 2016; Imran et al., 2013). Gondi et al. (2015) fed diabetic rats a diet supplemented with mango peel powder. Results showed a significant increase in high-density lipoprotein, and decreases in lipid peroxidation, sugar in urine, fasting glucose, total cholesterol, and triglycerides, revealing the antidiabetic potential of mango peel. According to Saleh et al. (2014), the

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Valorization of Fruit Processing By-products

hypoglycemic properties of mango peel extracts are attributed to mangiferin. Mango peel extract also showed antibacterial activity against Staphylococcus aureus when associated with antibiotics (Oliveira et al., 2011). The combination of the mango peel extract with fish gelatin resulted in the production of a structured, dense, and continuous biodegradable film. The addition of 1%
5% of the extract to gelatin was the best biofilm composition for food storage and elimination of free radicals. This type of product reuses mango by-products and further contributes to the reduction of food loss as it offers an active packaging that prolongs food shelf life (Adilah et al., 2018). Ajila et al. (2007) evaluated the antioxidant activity of mango peel extracts from the Raspuri and Badami varieties. Mature fruit extracts showed higher anthocyanins and carotenoids content, while immature fruit extracts showed higher polyphenol content. All fruit extracts showed great antioxidant activity in different systems; therefore these extracts could be used in nutraceutical and functional foods. Other uses of mango peel have been proposed, such as dietary fibers extraction by a simple process: grinding, washing with water, and drying as described by Larrauri et al. (1996). The same research group also extracted dietary fibers from mango peel with 0.07 g of total polyphenols, 281 g of water solubility, and 11.4 g of water retention per g of dry matter. Notably, peel by-products are composed of distinct structures, and the methods of extracting a particular by-product, in general, include separating steps (Kansci et al., 2008; Ajila et al., 2007). Thus the joining of processes in order to obtain two or more by-products is an interesting alternative to increase the viability of mango waste use as evidenced by Berardini et al. (2005), who validated two combined methods of pectin and phenolic compounds recovery from mango peel by sulfuric acid acidification followed by precipitation with ethanol and the addition of resins to extract phenolic compounds. Therefore the use of mango peel as a by-product is promising to increase profitability and reduce the environmental impacts of fruit processing.

8.4

Mango seed

Mango core wastes are made up of the pit and seed. The pit is the outermost layer of the kernel that surrounds the almond, corresponds to up to 6% of fruit mass, and contains large amounts of cellulose, hemicellulose, and lignin. The seed (also called the kernel) is the main core part, corresponds to 9%
40% of fruit mass, consists of the embryo and albumen, and contains starch, cellulose, hemicellulose, lignin, and fatty acids (oleic, stearic, palmitic, and linoleic acids). The seed is enveloped by two papyraceous teguments, the testa (seed coat), which are white-silver and well adhered to the endocarp, and the tegmen, which is brown and covers the seed (Manica, 2001). Fig. 8.4 summarizes the main by-products that can be obtained directly from mango seeds (flour, fat, and starch), which can be used as food ingredients for the main products of mango mesocarp. The following describes recent studies into seed composition, methods of extraction, and applications. Mango seed is recalcitrant, intolerant to desiccation, and maintains a high water content even after the complete maturation of the fruit. The high water content hinders the seed conservation and its use as a by-product, and thus

FIGURE 8.4 By-products from mango seed.

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treatments that prevent seed decomposition, such as sterilization, freezing, or dehydration, are necessary (Okoruwa and Omoragbon, 2017; Nzikou et al., 2010). Dehydration is an interesting treatment to avoid rancidification, since mango seeds have a high lipid content (Singhania et al., 2009). Among the mango seed by-products, the flour (also called mango seed powder) is obtained after tegmens removal, kernel grinding, extraction with organic solvents, and drying. The flour can be used as a supplement for animal and human feeding, and as a raw material for the extraction of starch and fat (Farag, 2001; Ravindran and Sivakanesan, 1996). In animal feed the palatability of mango seed powder may be affected by the high content of tannins. The mixture of up to 50% (w/w) of powder to the regular food was well accepted by ruminants, however, formulations above 70% (w/w) showed low acceptance. Alkali and acid treatments can be used to remove the majority of tannins and, consequently, increase food palatability (Sanon et al., 2013). In the animal feed the powder can be used as a supplement in order to increase the digestibility (Okoruwa and Omoragbon, 2017). Regarding human feeding, mango seed flour contains, in general, fewer proteins than other flours, such as wheat, maize, and barley. However, mango seed flour has a higher relative concentration of essential amino acids, such as leucine, arginine, valine, histidine, lysine, isoleucine, threonine, and phenylalanine (Abdalla et al., 2007). Torres-Leo´n et al. (2016) reported a high mineral content in mango seeds that may vary according to the fruit variety. The main found minerals are potassium, phosphorus, and magnesium, all nutrients that play an essential role in the human metabolism. Okpala and Gibson-Umeh (2013) reported the presence of antinutritional substances, such as trypsin and hydrogen cyanide inhibitors, in concentrations that were not harmful to human and animal health. However, seed composition may vary according to the characteristics of the original fruit. Oil is another product that can be obtained from intact mango seeds or flour by alcohol distillation, followed by alkaline treatment. The oil is also called mango seed fat because it remains in the solid state at room temperature (until 27 C) (Jahurul et al., 2014; Abdalla et al., 2007). The oil composition may vary according to each seed, but in general contains 12
25 g of lipids per 100 g of dry seed, similar to soybean grains (Ajiwe et al., 1994), has a low degree of unsaturation, a high oxidative stability, and its major fatty acids are palmitic (C16:0), stearic (C18:0), oleic (C18:1), and linoleic (C18:2) (Jahurul et al., 2014; Abdalla et al., 2007). The mango seed fat has similar physicochemical properties to cocoa butter, and it can substitute for it in foods. Jahurul et al. (2014) proposed the substitution of cocoa butter with a mixture of mango and palm oil, as they have a similar chemical composition, iodine, saponification, and acidity, and advantages regarding temperature resistance. Lipids extracted from mango seeds can also be used for the production of bioresin and can replace petroleum-based resins. In a previous study, the oil extraction from the variety Rosigold resulted in a good quality bioresin with iodine content below 50 mg per 100 g of oil (Sadiq et al., 2017). Methyl ester of mango seed oil was tested as a fuel in blends with diesel. The biodiesel was produced, according to Vijayarai and Sathiyagnanam (2016), using crude mango seed oil by a transesterification method. The combination of 25% methyl ester of mango seed oil and 75% diesel was the best for an effective biofuel. Dutra et al. (2017) studied the physicochemical composition of mango seed oil, which was proved to be a promising raw material for the fuel industry since it has high quality and low cost. Mango seeds can also be used for starch extraction, by mixing the seeds with water and grinding until a pasty texture is reached, then the mixture is alkalized and an organic solvent is added. The content is decanted and the supernatant discarded. The lower fraction is then washed with organic solvents and filtered; the final filtrate is considered the concentrated starch extract (Kaur et al., 2007). Patil et al. (2014) extracted starch from mango seeds belonging to the variety ‘Kala amba’ and the obtained product showed a moisture content of 14.93%, an ash content of 0.12%, and an amylose content of 35.06%, with an initial gelatinization temperature of 50 C, and thus classified as suitable for the food industry. Silva et al. (2013) used seeds from the variety Tommy Atkins and achieved a starch yield rate of 59.82% (w/w), with a moisture content of 10.14% and ash content of 0.35%. The obtained starch was considered suitable as a thickener for the production of dairy drinks, due to having the necessary physicochemical and sensorial characteristics for commercialization. In addition, the functional properties of mango starch can be improved by the addition of guar and xanthan gums, which decrease swelling power, facilitate gelatinization, and increase the cooking temperature, water absorption, viscosity, and firmness of the preparations (Nawab et al., 2016). Mango seeds also showed antioxidant activity due to the high concentration of phenolic compounds, approximately 112 mg in 100 g of dry seed (Abdalla et al., 2007). The antioxidant composition varies according to the characteristics of each seed. Soong and Barlow (2004) reported the presence of campesterol, β-sitosterol, stigmasterol, and tocopherol, while Schieber et al. (2003) found polyphenols, sesquiterpenoids, phytosterols, and minerals such as selenium and zinc.

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Different studies have reported that mango seeds are composed of bioactive compounds and can be used to improve human and animal health. Rajan et al. (2015) reported that mango seeds are popularly used for the treatment of symptoms such as vomiting, dysentery, and heartburn. The same authors evaluated the effect of mango seed extracts in rats treated with castor oil, a diarrhea inducer, and concluded that the extract inhibited intestinal permeability and decreased intestinal motility. Sowmiya et al. (2009) found dried mango seeds consisted of approximately 15% tannins and correlated this compound with the antidiarrhea effect of seeds. Rivera et al. (2006) studied the antiallergic effect of glucosylxanthone mangiferin, expanding the applications of mango seed extracts. Mango seed extracts studied by Vega-Vega et al. (2016), showed a high content of gallic acid. These extracts were applied to fresh mango pulp, aiming to increase antioxidant and antibacterial activity. Treated mango pulp showed higher antioxidant and antimicrobial activity, inhibiting 80% bacteria and 97% fungus. Alok et al. (2013) analyzed the antibacterial properties of M. indica L. seed extracts of two varieties, Bagnapalli and Senthura. Both extracts showed antibacterial activity against S. aureus and Pseudomonas aeruginosa. In addition, the variety Bagnapalli showed similar activity to the standard antibiotic ampicillin. Mutua et al. (2016) also demonstrated a high antimicrobial activity of mango kernel against S. aureus, P. aeruginosa, Bacillus subtilis, and Escherichia coli, proving the potential of the mango kernel for industrial applications as food additives and pharmaceuticals. Mango seed extracts may also have activities against bacteria and toxins. According to Asif et al. (2016), the phenolic groups of kernel, mainly the tannins, interact with the bacterial hydrophilic membranes modifying their permeability and resulting in a proton pump failure, a decline of the membrane potential, an ATP pool deficiency, and a loss of ions, preventing microbial growth. Abdel-Aty et al. (2018) also evidenced the medicinal importance of the phenolic compounds of mango kernel, as treatment for wounds caused by the attack of two vipers, Cerastes cerastes and Echis coloratus (common in Egypt). Carbohydrates of mango seed were extracted through pyrolysis—the transformation and decomposition of compounds by heat treatment—as described by Ganeshan et al. (2017), and three chemicals were obtained: D-allose (C6H12O6), levoglucosan (C6H10O5), and 3-furanmethanol (C5H6O2). D-Allose (C6H12O6) is a glucose epimer, rare and bioactive, that acts by inducing a tumor suppressor gene that interacts with thioredoxin, to inhibit the growth of cancer cells. Levoglucosan (C6H10O5) is an organic compound that can be used to produce fermentable sugar and synthesize chiral polymers, such as nonhydrolyzable glycoside. 3-Furanmethanol (C5H6O2) is a component of carbohydrate aromatic compounds. De-Goes et al. (2019) used mango juice processing waste—peel and seed—as an adsorbent powder for the removal of toxic species of chromium (Cr VI) from aquatic systems and attested the bioremediation capacity of mango waste. Henrique et al. (2013) described other applications of mango seeds, such as in the production of cellulose nanocrystals (CNCs) that can be used as antimicrobial films, transparent films, flexible displays, biomedical implants, molds for electronic components, separation membranes, batteries, electroactive polymers, among others. Silva et al. (2019) used starch nanocrystals and CNCs, both from the mango kernel of variety Tommy Atkins, to produce a consistent biofilm with biodegradable and edible properties as an alternative food packaging. Mango seed is undoubtedly a source of several valuable and novel compounds, which can be used in the manufacture of new products, in nutritional improvement, and food storage prolongation. Mango seed extracts can also be used as an adsorbent of heavy metals, as antioxidants, and as bactericides. These properties show the need for further studies of possible sustainable applications of mango seed and other plant wastes.

8.5

Mango waste as substrate

Among the procedures for the production of microbial bioactive compounds, there are two fermentation processes: submerged/liquid (SmF) and solid state (SSF). SmF demands more water for microbial growth (Lima et al., 2001; Fleuri, 2016), while SSF occurs in solid substrates (Pinto et al., 2005; Fleuri, 2016). Although SmF is the most used technique on the industrial scale because it allows a greater process control, SSF has advantages in the cultivation of filamentous fungi since it mimics their natural habitat (Barrios-Gonzalez, 2012; Ho¨lker et al., 2004), resulting in a higher enzyme yield. In addition, SSF produces less wastewater, which reduces the risk of bacterial contamination, and the enzymes produced through SSF are usually more resistant to temperature and pH variations (Ho¨lker and Lenz, 2005). The technology employed in SSF faces some obstacles, such as the control of physicochemical conditions (temperature and pH), lack of information about transport, and kinetic aspects of microbial growth and enzyme production, as well as difficulties in the reproducibility of the experiments at the industrial scale (Castro and Pereira, 2010). In recent decades SSF has gained significant space due to its advantages such as lower energy use, higher produced volume, use of agroindustrial waste as a carbon source, high amount of combinations of wastes and

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microorganisms, low cost, and wide biotechnological applicability (El-Bakry et al., 2015; Pandey, 1991; Pandey and Radhakrishnan, 1992). SSF is mainly employed in the bioconversion of wastes into biofuels, the bioremediation or biodegradation of toxic substances, the optimization of biomass use in the design of biorefineries, animal feed production, and secondary metabolites with high added value (Maity, 2015; Kamm and Kamm, 2004; Couto and Sanroma´n, 2006). The characteristics of SSF are economical and environmentally advantageous since there is a reduction of expenses and the avoidance of wastes generation due to the exclusion of the stages of extraction and filtration of the global process. The SSF efficiency depends on the interrelation between the physiology of the microorganisms and the culture medium’s physicochemical factors, such as temperature, humidity, macro- and micronutrients, pH and aeration (Singhania et al., 2009). In general, fermentation processes produce microbial biomass or biomolecules of industrial interest, and agroindustrial wastes are indirect sources of these promising compounds. The importance of the use of wastes as substrates in fermentative processes lies in the possibility of producing a great variety of products, due to the great diversity of both agroindustrial wastes and microorganism fermentation products marked in expanding and generating billions of dollars, as the example of biocatalysts that generated 5.5 billion dollars in world trade in 2018, and has a prospect of 7 billion by 2023 (BCC Research, 2018). Mango wastes can also be used as substrates for SSF. Mango peel was tested as substrate for Fusarium moniliforme polygalacturonase (E.C. 3.2.1.15), an important enzyme group that degrades pectin (Sudheer Kumar et al., 2010). When hydrolyzing pectin, polygalacturonase improves fruit preservation or processing (Lima, 2002), and these properties are desired in the food industry in the extraction and clarification of fruit juice, increasing juice yield by 40% (Palanivelu, 2006). Santos et al. (2013) tested mango wastes as substrates for Aspergillus niger, aiming to produce endoglucanases (EC 3.2.1.4), a class of hydrolytic enzymes of wide industrial interest. The enzymes showed optimal performance at low pH, which confirms the potential of endoglucanases to degrade cellulose in acidic pH bioprocesses. It is an interesting characteristic for industry, since one of the biotechnology challenges for cellulases is their stability, as well as low production costs. Beside the enzymes, other products can be obtained using different bioprocesses, such as alcoholic, lactic, and acetic fermentation. Alcoholic fermentation is the metabolization of sugar to produce ethanol and carbon dioxide, and is widely applied in the biofuel and brewery industries (Bastos, 2007). Acetic fermentation is the oxidation of ethyl alcohol to synthesize acetic acid, and it is used for the production of vinegar and the deterioration of food and beverages (Bortolini et al., 2001). Lactic fermentation converts glucose into lactic acid, which is used as a preservative and acidulant in the food industry, and in the manufacture of biodegradable plastics and rigid packaging for food preservation (Tsuji and Fukui, 2003). In the research of Jawad et al. (2013), lactic acid was produced by SmF using microorganism and mango peel, with a maximum yield after 6 days of incubation. Fernando et al. (2014) proposed the production of bioethanol under SmF, combining Saccharomyces cerevisiae Y2034 with different mango by-products (pulp, peel, and seed). They obtained fermentable sugars for the production of bioethanol. In the study conducted by Ethiraj and Suresh (1992) the mixture of peel and seeds was subjected to alcoholic fermentation, using S. cerevisiae var. ellipsoideus until reaching about 3% alcohol. Acetic fermentation was induced using Acetobacter rancans, and the final product was considered a good quality vinegar, with 5% acetic acid and a soft mango flavor. Mango waste can also be used directly to obtain bioactive substances, as shown by Lasano et al. (2019). In this research, the antidiabetic activity of mango wastes was investigated for the first time. In another study different solvents were analyzed regarding the inhibitory effect of mango wastes against α-amylase and α-glucosidase. Mango seed showed higher inhibitory potential against α-amylase and α-glucosidase (2.67
9.83 and 0.29
2.10 mg/mL, respectively), represented by the IC50 value (inhibitor concentration required to reach 50%), when compared to the peel (9.96
33.72 and 10.52
59.45 mg/mL) (Sarmadi et al., 2012). Mutua et al. (2017) investigated the antimicrobial and antioxidant activity of extracts from four mango varieties (Apple, Kent, Ngowe, and Sabine). The results showed higher inhibition rate against E. coli in seed extracts of Apple and Sabine (1.93 and 1.73 cm) in comparison to Kent and Ngowe (1.13 and 1.10 cm). For S. aureus the higher inhibition was 2.07 cm using Ngowe and Kent extracts, while for the inhibition of Candida albicans Ngowe, Apple, and Sabine were more effective (2.23, 2.13, and 1.83 cm) in comparison to Kent (1.63 cm). Mango seeds showed high antioxidant activity (92.22%) at 20 mg/mL and a high polyphenols content (68.71
72.05 mg/gallic acid equiv.).

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Valorization of Fruit Processing By-products

A microemulsion system based on Thai mango seed extract (ESM) was developed and characterized for topical dermal administration (Leanpolchareanchai et al., 2014). Microemulsions have a wide pharmaceutical application when compared to conventional methods of applying medications such as gels, ointments, and creams (Lawrence and Rees, 2000). Thus the analysis of skin absorption and irritation was investigated ex vivo. ESM was not considered cytotoxic, resulting in 1%
33% human fibroblasts deaths. Penetration tests showed a greater penetration of ESM, from 7.7 to 59.9 times, using microemulsions when compared to ESM-only treatments. Regarding irritability, the results confirmed that the microemulsion formulations were nonirritating (ΔTEWL , 6 g/m 2/h). Leanpolchareanchai et al. (2009) measured the antienzymatic activities of ESM against snake venom (Calloselasma rhodostoma and Naja kaouthia). From a molecular point of view, the activities of phospholipase A2, hyaluronidase, and L-amino acid oxidase from the snake venoms could be inhibited by the molecular binding of the enzymatic active site with ESM phenolic molecules. In vivo tests also analyzed antihemorrhagic and antidermonecrotic activities of the ESM against both venoms. The results of Garcia (2017) were promising regarding the obtainment of starch laurate from an ester extracted from mango kernel starch. This starch is used as a stabilizer in drilling fluids of oil wells. The modification of the starch allows a greater thermal stability and a decrease in its solubility in water. In addition, the rheological properties of the product allow its transformation into an additive polymer for nonaqueous drilling fluids. This kind of fluid is indispensable for nonoil activities, as it hampers collapse, prevents clogging, and increases penetrability rates. It is important to point out that the use of mango wastes as a substrate of fermentation processes may occur after the extraction of different products of peel and seed, depending on the microbial ability (Fig. 8.5) (Fleuri, 2016). Thus it is possible to reach a maximum use of all the fractions of mango wastes, extracting a greater number of compounds with different applications. In addition, after fermentation other bioactive compounds, such as enzymes, fermentable sugars, and microbial cell mass, can be produced, leading to a mango biorefinery. Fermentable sugars, for example, may be used for the production of plant growth regulators, sweeteners, enzymes, ethanol, organic acids, pigments, and solvents, among other products (Fleuri et al., 2013). The use of mango waste refers to biorefineries, which are necessary technologies between the biological raw materials, industrial intermediates, and final products (Kamm and Kamm, 2004). An example of success would be an analogue to an oil refinery that produces several fuels and petroleum products (Demirbas, 2009; Forster-Carneiro et al., 2013). The benefit of a biorefinery is also environmental due to the use of and reduced generation of wastes, and the implementation of a sustainable cycle. In this sense, obtaining and/or producing different biomolecules taking into account the basic concept of a biorefinery, with the use of effluents, is an interesting strategy regarding the effective production of any product, with environmental appeal and with an adequate cost. The current approaches of fruit bioremediation include the production of bioactive compounds such as pectin, lipids, flavonoids, dietary fibers, and biofuels from fruit processing waste (FPW). Currently, the use of FPW as a raw material for the extraction of high-value-added biomolecules is limited; however, the efficient utilization of fruit biomass tied to an already existing food production chain makes the process more viable and economical, by sustainably using resources such as water and fertilizers, and efficiently managing soils (Banerjee et al., 2017). Among the problems with resources, the wastewater generated in the processing of fruits is a preponderant factor, since freshwater is scarce. Thus measures aiming to reduce wastewater in the food chain should be adopted by improving water use efficiency in agriculture and food production (Ridoutt et al., 2010). The fruit processing wastewater may contain many nutrients and may be used as a liquid medium for liquid fermentation as well as a moistening solution for the substrates of SSF (Fleuri, 2016). Recently the costs and profitability associated with a biorefinery of mango processing were evaluated, considering the recovery of isolated pectin, the set of pectin and seed oil, and the biorefinery, obtaining of several products. In a plant with a capacity of 10 tons/h, the study conducted by Arora et al. (2018) indicated that mango processing wastes FIGURE 8.5 Maximum utilization of mango processing wastes in an integrative manner and use of the final waste as substrate for fermentation processes.

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can be transformed into higher value products in three scenarios, although the best model was the production of pectin and oil in an integrated manner. The best results occurred with the greater capacity of the pilot plant, however, there were difficulties, such as the unavailability and storage of perishable seasonal raw material for a longer period, and thus problems maintaining the original fruit composition. The authors concluded that the large amounts of mango processing wastes that are currently discarded worldwide could be an excellent raw material for the recovery of multiple products, encouraging a circular economy and wealth generation from surpluses.

8.6

Prospects and conclusion

The mango is among the most consumed fruits worldwide and, although it is still mostly appreciated in fresh form, the consumption of mango processed products have grown and, consequently, its waste generation has also grown, since the pulp (main product) corresponds to approximately half of the fruit mass (El-Kholy et al., 2008). The world economic scenario has forced fruit processing companies to increasingly seek the possibilities of associating profitability with sustainability (Okino-Delgado et al., 2018), which has stimulated the transformation of waste into by-products as a way of maintaining the sector’s competitiveness and longevity. In this context, mango processing wastes have a rich composition, which allows the production of several by-products. Mango by-products can be used by the final consumer or as food ingredients in diverse segments such as foods, pharmaceuticals, fine chemicals, cosmetics, cleaning products, and personal hygiene products (Okino-Delgado and Fleuri, 2016). In addition, mango like other fruits are rich sources of vitamins, minerals, fiber, sugars, and proteins, and play a key role in food security and nutrition. Although the hunger rate is declining, obesity rates in adults and anemia in women of reproductive age continue to grow. Good nutrition is identified by FAO as the lifeblood of sustainable development that will drive the changes to a most sustainable and prosperous future (FAO, 2018; Sharma et al., 2017). Therefore mango processing wastes will also play an important role in achieving balanced diets in the near future, considering the rich composition of mango wastes. Among the challenges of using mango wastes for biotechnological purposes are the seasonality of the main producing countries and the low processing rate. The instability of raw material supplies makes it hard to establish specialized industries. Another challenge is to standardize mango by-products since each mango variety from each producer region has different characteristics, and this framework impacts the yield of pulp/ waste, as well as the composition of each mango fraction. Therefore the use of mango processing wastes as by-products and as substrates for fermentation processes represents a promising path in the search for more profitable and sustainable systems. This new scenario has caused disruptive and innovative changes in the sector, by the incorporation of new products to traditional processes.

References Abdalla, A.E., Darwish, S.M., Ayad, E.H., El-Hamahmy, R.M., 2007. Egyptian mango by-product 1. Compositional quality of mango seed kernel. Food Chem. 103 (4), 1134
1140. Abdel-Aty, A.M., Salama, W.H., Hamed, M.B., Fahmy, A.S., Mohamed, S.A., 2018. Phenolic-antioxidant capacity of mango seed kernels: therapeutic effect against viper venoms.. Rev. Bras. Farmacog. . Available from: https://doi.org/10.1016/j.bjp.2018.06.008. Abdul Aziz, N.A., Wong, L.M., Bhat, R., Cheng, L.H., 2012. Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var. Chokanan) in terms of chemical composition, antioxidant compounds and functional properties. J. Sci. Food Agric. 92 (3), 557
563. Available from: https://doi.org/10.1002/jsfa.4606. Adilah, A.N., Jamilah, B., Noranizan, M.A., Hanani, Z.A.N., 2018. Utilization of mango peel extracts on the biodegradable films for active packaging. Food Packag. Shelf Life 16, 1
7. Available from: https://doi.org/10.1016/j.fpsl.2018.01.006. Ajila, C., Naidu, K., Bhat, S., Rao, U., 2007. Bioactive compounds and antioxidant potential of mango peel extract. Food Chem. 105 (3), 982
988. Available from: https://doi.org/10.1016/j.foodchem.2007.04.052. Ajiwe, V.I.E., Umerie, S.C., Okeke, C.A., Oburota, V.N., 1994. Extraction and utilisation of cassava seed oil. Bioresour. Technol. 47 (1), 85
86. Alok, P., Keerthana, V., Kumar, J.C., Ratan, K., Chand, A.D., 2013. Antibacterial property of two different varieties of Indian mango (Mangifera indica) kernel extracts at various concentrations against some human pathogenic bacterial strains. Int. Res. J. Biol. Sci. 2, 28
32. Anthon, G.E., Barrett, D.M., 2008. Combined enzymatic and colorimetric method for determining the uronic acid and methylester content of pectin: application to tomato products. Food Chem. 110, 239
247. Arora, A., Banerjee, J., Vijayaraghavan, R., Macfarlane, D., Patti, A.F., 2018. Process design and techno-economic analysis of an integrated mango processing waste biorefinery. Ind. Crops Prod. 116, 24
34. Available from: https://doi.org/10.1016/j.indcrop.2018.02.061. Asif, A., Farooq, U., Akram, K., Hayat, Z., Shafi, A., Sarfraz, F., et al., 2016. Therapeutic potentials of bioactive compounds from mango fruit wastes. Trends Food Sci. Technol. 53, 102
112. Available from: https://doi.org/10.1016/j.tifs.2016.05.004. Bally, I.S.E., 2006. Mangifera indica (mango). Traditional Trees of Pacific Islands: Their Culture, Environment, and Use. Permanent Agricultural Resources, Holualoa, HI, pp. 441
464.

178

Valorization of Fruit Processing By-products

Banerjee, J., Singh, R., Vijayaraghavan, R., MacFarlane, D., Patti, A.F., Arora, A., 2017. Bioactives from fruit processing wastes: Green approaches to valuable chemicals. Food Chem. 225, 10
22. Available from: https://doi.org/10.1016/j.foodchem.2016.12.093. Banerjee, J., Vijayaraghavan, R., Arora, A., Macfarlane, D.R., Patti, A.F., 2016. Lemon juice based extraction of pectin from mango peels: waste to wealth by sustainable approaches. ACS Sustain. Chem. Eng. 4 (11), 5915
5920. Available from: https://doi.org/10.1021/acssuschemeng.6b01342. Barrios-Gonzalez, J., 2012. Solid-state fermentation: physiology of solid me´dium, its molecular bases and applications. Process Biochem. 47, 175
185. Barta, J., Cano, M.P., Gusek, T.W., Sidhu, J.S., Sinha, N.K., 2006. Handbook of Fruits and Fruit Processing. Blackwell Publishing. Bastos, V.D., 2007. Etanol, Alcoolquı´mica e Biorrefinarias. BNDS. BCC Research, 2018. Global markets for enzymes in industrial applications. Disponı´vel em ,https://www.bccresearch.com/market-research/biotechnology/global-markets-for-enzymes-in-industrial-applications-bio030k.html. (acessado 12.11.18). Berardini, N., Kno¨dler, M., Schieber, A., Carle, R., 2005. Utilization of mango peels as a source of pectin and polyphenolics. Innov. Food Sci. Emerg. Technol. 6 (4), 442
452. Available from: https://doi.org/10.1016/j.ifset.2005.06.004. Bortolini, F., Sant’anna, E.S., Torres, R.C., 2001. Comportamento das fermentac¸o˜es alcoo´lica e ace´tica de sucos de kiwi (Actinidia deliciosa): composic¸a˜o dos mostos e me´todos de fermentac¸a˜o ace´tica. Food Sci. Technol. 21 (2), 236
243. Castro, A.M., Pereira Jr., N., 2010. Produc¸a˜o, propriedades e aplicac¸a˜o de celulases na hidro´lise de resı´duos agroindustriais. Quı´mica Nova 33, 181
188. Couto, S.R., Sanroma´n, M.A., 2006. Application of solid-state fermentation to food industry—a review. J. Food Eng. 76 (3), 291
302. Dar, M.S., Oak, P., Chidley, H., Deshpande, A., Giri, A., Gupta, V., 2016. Nutrient and flavor content of mango (Mangifera indica L.) cultivars: an appurtenance to the list of staple foods. In: Simmonds, M., Preedy, V. (Eds.), Nutritional Composition of Fruit Cultivars. Academic Press, San Diego, CA, pp. 445
467. De-Goes, C., Silva, J.G.A.E., De-Brito, E.S., Becker, H., Trevisan, M.T.S., Owen, R.W., 2019. Chromium (VI) remediation in aqueous solution by waste products (peel and seed) of mango (Mangifera indica L.) cultivars. Environ. Sci. Pollut. Res. (in press). Demirbas, A., 2009. Progress and recent trends in biodiesel fuels. Energy Convers. Manag. 50 (1), 14
34. Dutra, E.D., De-Lima, T.A., de Oliveira-Souza, J.L., Silva, J.G.V., Da-Silva, K.A., Da-Silva, F., et al., 2017. Characterization of fat and biodiesel from mango seeds using 1H NMR spectroscopy. Biomass Convers. Biorefin. 8 (1), 135
141. El-Bakry, M., Abraham, J., Cerda, A., Barrena, R., Ponsa, S., Gea, T., et al., 2015. From wastes to high value added products: novel aspects of SSF in the production of enzymes. Crit. Rev. Environ. Sci. Technol. 45, 1999
2042. Elhassaneen, Y., El-Waseef, S., Fathy, F., Ahmed, S.S., 2016. Bioactive compounds and antioxidant potential of food industry by-products in Egypt. Am. J. Food Nutr. 4, 1
7. Available from: https://doi.org/10.12691/ajfn-4-1-1. El-Kholy, K.H.F., et al., 2008. Use of some agro-industrial by products in Nile Tilapia fish diets. In: 8th International Symposium on Tilapia in Aquaculture. Ethiraj, S., Suresh, E.R., 1992. Studies on the utilization of mango processing wastes for production of vinegar. J. Food Sci. Technol. 29, 48
50. FAO—Food and Agriculture Organization of the United Nations, 2011. Study Conducted for the International Congress. Save food! Disposable in ,http://www.fao.org/economic/est/est-commodities/tropical-fruits/en/. (accessed January 2019.). FAO—Food and Agriculture Organization of the United Nations, 2017. Global initiative on food loss and waste. Disposable in ,http://www.fao.org/ 3/a-i7657e.pdf. (accessed January 2019.). FAO—Food and Agriculture Organization of the United Nations, 2018. Tropical fruit stats—mango data. Disposable in ,http://www.fao.org/economic/est/est-commodities/tropical-fruits/en/. (accessed in January 2019.). Farag, M.D.E.H., 2001. The enhancement of the nutritive value of mango seed kernels for poultry by thermal treatment and radiation processing. Archiv. Tierernaehrung 54 (1), 61
79. Available from: https://doi.org/10.1080/17450390109381966. Farnsworth, K.D., Adenuga, A.H., De Groot, R.S., 2015. The complexity of biodiversity: a biological perspective on economic valuation. Ecol. Econ. 120, 350
354. Fernando, S.E.L., Bianca, Y.P.S., Sergio, S.T., Eapen, D., Sebastian, P.J., 2014. Evaluation of agro-industrial wastes to produce bioethanol: case study-mango (Mangifera indica L.). Energy Procedia 57, 860
866. Fleuri, L.F., 2016. Resı´duos como fontes diretas e indiretas de enzimas. Tese (Livre doceˆncia)—Universidade Estadual Paulista “Ju´lio de Mesquita Filho”—UNESP. Fleuri, L.F., Kawaguti, H.Y., Pedrosa, V., Vianello, F., Lima, G.P.P., Novelli, P.K., et al., 2013. Exploration of microorganisms producing bioactive molecules of industrial interest by solid state fermentation. In: Giuseppina Pace Pereira Lima; Fa´bio Vianello. (Org.). Food Quality, Safety and Technology, 1ed. Springer-Verlag, Wien, pp. 1
163. Forster-Carneiro, T., Berni, M.D., Dorileo, I.L., Rostagno, M.A., 2013. Biorefinery study of availability of agriculture residues and wastes for integrated biorefineries in Brazil. Resour. Conserv. Recy. 77, 78
88. Future Market Insights, 2018. Economic report—fruit pomace market: abundance of fibre content in fruit pomace to enhance utilization in food processing: global industry analysis (2013
2017) and opportunity assessment (2018
2027). Sample disposable in ,https://www.futuremarketinsights.com/reports/fruit-pomace-market. (accessed January 2019.). Ganeshan, G., Shadangi, K.P., Mohanty, K., 2017. Thermo-chemical conversion of mango seed kernel and shell to value added products. J. Anal. Appl. Pyrol. 121, 403
408. Garcia, C.S.N., 2017. Laurato de amido obtido a partir de amido extraı´do do caroc¸o da manga Tommy Atkins: sı´ntese, caracterizac¸a˜o e aplicac¸a˜o em fluidos de perfurac¸a˜o na˜o aquosos. Dissertac¸a˜o (Mestrado em Cieˆncia e Engenharia de Materiais)—Centro de Cieˆncias Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal.

Mango Chapter | 8

179

Gondi, M., Basha, S.A., Bhaskar, J.J., Salimath, P.V., Rao, U.J., 2015. Anti-diabetic effect of dietary mango (Mangifera indica L.) peel in streptozotocin-induced diabetic rats. J. Sci. Food Agric. 95, 991
999. Available from: https://doi.org/10.1002/jsfa.6778. Gragasin, M.C.B., Ligisan, A.R., Torres, R.C., Estrella., R., 2014. Utilization of mango peels as source of pectin, PHilMech Technical Bulletin, vol. 4. Philippine Center for Postharvest Development and Mechanization, Science City of Mun˜oz, Nueva Ecija, no. 1. Henrique, M.A., Silve´rio, H.A., Flauzino Neto, W.P., Pasquini, D., 2013. Valorization of an agro-industrial waste mango seed by the extraction and characterization of its cellulose nanocrystals. J. Environ. Manag. 121, 202
209. Ho¨lker, U., Ho¨fer, M., Lenz, J., 2004. Biotechnological advantages of laboratory-scale solid-state fermentation with fungi. Appl. Microbiol. Biotechnol. 64 (2), 175
186. Ho¨lker, U., Lenz, J., 2005. Solid-state fermentation—are there any biotechnological advantages? Curr. Opin. Microbiol. 8, 301
306. Hu, H., Zhao, Q., Pang, Z., Xie, J., Lin, L., Yao, Q., 2018. Optimization extraction, characterization and anticancer activities of polysaccharides from mango pomace. Int. J. Biol. Macromol. 117, 1314
1325. Available from: https://doi.org/10.1016/j.ijbiomac.2018.05.225. Hui, Y.H., 2007. Handbook of Food Products Manufacturing, 2 Volume Set. Wiley-Interscience, Hoboken, NJ. Imran, M., Butt, M.S., Anjum, F.M., Sultan, J.I., 2013. Chemical profiling of different mango peel varieties. Pak. J. Nutr. 12, 934
942. Available from: https://doi.org/10.3923/pjn.2013.934.942. Jahurul, M.H.A., Zaidul, I.S.M., Norulaini, N.A.N., Sahena, F., Abedin, M.Z., Ghafoor, K., et al., 2014. Characterization of crystallization and melting profiles of blends of mango seed fat and palm oil mid-fraction as cocoa butter replacers using differential scanning calorimetry and pulse nuclear magnetic resonance. Food Res. Int. 55, 103
109. Jahurul, M.H.A., Zaidul, I.S.M., Ghafoor, K., Al-Juhaimi, F.Y., Nyam, K.-L., Norulaini, N.A.N., et al., 2015. Mango (Mangifera indica L.) byproducts and their valuable components: a review. Food Chem. 183, 173
180. Jawad, A.H., Alkarkhi, A.F.M., Jason, O.C., Easa, A.M., Nik-Norulaini, N.A., 2013. Production of the lactic acid from mango peel waste—factorial experiment. J. King Saud. Univ. Sci. 25 (1), 39
45. Available from: https://doi.org/10.1016/j.jksus.2012.04.001. Kamm, B., Kamm, M., 2004. Principles of biorefineries. Appl. Microbiol. Biotechnol. 64 (2), 137
145. Kansci, G., Koubala, B.B., Mbome, I.L., 2008. Biochemical and physiochemical properties of four mango varieties and some quality characteristics of their jams. J. Food Process Preserv. 32 (4), 644
655. Kaur, L., Sing, J., Liu, Q., 2007. Starch—a potential biomaterial for biomedical applications. In: Mozafari, M.R. (Ed.), Nanomaterials and Nanosystems for Biomedical Applications. Springer, Dordrecht, pp. 83
98. Koubala, B.B., Kansci, G., Mbome, L.I., Cre´peau, M.-J., Thibault, J.-F., Ralet, M.-C., 2008a. Effect of extraction conditions on some physicochemical characteristics of pectins from “Ame´liore´e” and “Mango” mango peels. Food Hydrocolloid. 22 (7), 1345
1351. Available from: https://doi.org/ 10.1016/j.foodhyd.2007.07.005. Koubala, B.B., Mbome, L.I., Kansci, G., Mbiapo, F.T., Cre´peau, M.-J., Thibault, J.-F., et al., 2008b. Physicochemical properties of pectins from ambarella peels obtained using different extraction conditions. Food Chem. 106 (3), 1202
1207. Larrauri, J.A., Rupe´rez, P., Borroto, B., Saura-Calixto, F., 1996. Mango peels as a new tropical fibre: preparation and characterization. LWT-Food Sci. Technol. 29 (8), 729
733. Available from: https://doi.org/10.1006/fstl.1996.0113. Lasano, N.F., Hamid, A.H., Karim, R., Dek, M.S.P., Shukri, R., Shazini Ramli, N., 2019. Nutritional composition, anti-diabetic properties and identification of active compounds using UHPLC-ESI-orbitrap-MS/MS in Mangifera odorata L. peel and seed kernel. Molecules 24 (2), 320. Lawrence, M.J., Rees, G.D., 2000. Microemulsion-based media as novel drug delivery systems. Adv. Drug Deliv. Rev. 45, 89
121. Available from: https://doi.org/10.1016/S0169-409X(00)00103-4. Lawson, T., Lycett, G.W., Aii, A., Chin, C.F., 2019. Characterization of Southeast Asia mangoes (Mangifera indica L.) according to their physicochemical attributes. Sci. Horticult. 243, 189
196. Leanpolchareanchai, J., Pithayanukul, P., Bavovada, R., Saparpakorn, P., 2009. Molecular docking studies and anti-enzymatic activities of Thai mango seed kernel extract against snake venoms. Molecules 14 (4), 1404
1422. Available from: https://doi.org/10.3390/molecules14041404. Leanpolchareanchai, J., Padois, K., Falson, F., Bavovada, R., Pithayanukul, P., 2014. Microemulsion system for topical delivery of Thai mango seed kernel extract: development, physicochemical characterisation and ex vivo skin permeation studies. Molecules 19 (11), 17107
17129. Available from: https://doi.org/10.3390/molecules191117107. Lima, M.A.C., 2002. Alterac¸o˜es bioquı´micas e fisiolo´gicas durante a maturac¸a˜o e o armazenamento de graviola sob refrigerac¸a˜o associada a 1metilciclopropeno e cera. Tese (doutorado)—Universidade Federal do Ceara´, Fortaleza. p. 208. Lima, U.A., Aquarone, E., Borzani, W., Schimidell, W., 2001. first ed. Biotecnologia Industrial, vol. 3. Blocher, Sa˜o Paulo, p. 616. Ma, X., Wu, H., Liu, L., Yao, Q., Wang, S., Zhan, R., et al., 2011. Polyphenolic compounds and antioxidant properties in mango fruits. Sci. Horticult. 129, 102
107. Maity, S.K., 2015. Opportunities, recent trends and challenges of integrated biorefinery: part II. Renew. Sustain. Energy Rev. 43, 1446
1466. Manica, I., 2001. Manga: Tecnologia, Produc¸a˜o, Po´s-colheita, Agroindu´stria e Exportac¸a˜o. Cinco Continentes, Porto Alegre, p. 617. Markets and Markets, 2018. Food & beverage processing equipment market by type (processing, pre-processing), application (bakery & confectionery, meat & poultry, dairy, alcoholic & non-alcoholic beverages), mode of operation, end-product form, and region
global forecast to 2023. Free sample disposable in ,https://www.marketsandmarkets.com/Market-Reports/food-processing-equipment-market-121668697.html. (accessed January 2019.). ´ Lvarez, J.A., Viuda-Martos, M., 2012. Chemical, technological and in vitro antioxiMartı´nez, R., Torres, P., Meneses, M.A., Figueroa, J.G., Pe´rez-A dant properties of mango, guava, pineapple and passion fruit dietary fibre concentrate. Food Chem. 135 (3), 1520
1526. Matheyambath, A.C., Subramanian, J., Paliyath, G., 2016. Mangoes. Encyclopedia of Food and Health. Academic Press, pp. 641
645.

180

Valorization of Fruit Processing By-products

Mulderji, R., 2019. Overview global mango market. Available from: ,https://www.freshplaza.com/article/2187370/overview-global-mango-market/. (accessed January 2019.). Mutua, J.K., Imathiu, S., Owino, W., 2016. Evaluation of the proximate composition, antioxidant potential, and antimicrobial activity of mango seed kernel extracts. Food Sci. Nutr. 5 (2), 349
357. Mutua, J.K., Imathiu, S., Owino, W., 2017. Evaluation of the proximate composition, antioxidant potential, and antimicrobial activity of mango seed kernel extracts. Food Sci. Nutr. 5 (2), 349
357. Narain, N., Bora, P.S., Narian, R., Shaw, P., 1998. Mango. In: Shaw, P.E., Chan, H.T., Nagy, S. (Eds.), Tropical and Subtropical Fruits. Agriscience Inc., Auburndale, FL, pp. 1
77. Nawab, A., Alam, F., Haq, M.A., Hasnain, A., 2016. Effect of guar and xanthan gums on functional properties of mango (Mangifera indica) kernel starch. Int. J. Biol. Macromol. 93, 630
635. Available from: https://doi.org/10.1016/j.ijbiomac.2016.09.011. Nwanekezi, E.C., Alawuba, O.C.G., Mkpolulu, C.C.M., 1994. Characterization of pectic substances from selected tropical fruits. J. Food Sci. Technol. Mysore 31 (2), 159
161. Nzikou, J.M., Kimbonguila, A., Matos, L., Loumouamou, B., Pambou-Tobi, N.P.G., Ndangui, C.B., et al., 2010. Extraction and characteristics of seed kernel oil from mango (Mangifera indica). Res. J. Environ. Earth Sci. 2 (1), 31
35. Okino-Delgado, C.H., Fleuri, L.F., 2016. Orange and mango byproducts: agro-industrial waste as source of bioactive compounds and botanical versus commercial description—a review. Food Rev. Int. 32 (1), 1
14. Available from: https://doi.org/10.1080/87559129.2015.1041183. Okino-Delgado, C.H., Prado, D.Z., Fleuri, L.F., 2018. Brazilian fruit processing, wastes as a source of lipase and other biotechnological products: a review. An. Acad. Bras. Cieˆnc. 90 (3), 2927
2943. Available from: https://doi.org/10.1590/0001-3765201820180095. Okoruwa, M.I., Omoragbon, E., 2017. Influence of differently processed mango seed kernel meal on performance response of West African dwarf goats fed spear grass based diet. Nigeria Agric. J. 48 (2), 129
135. Okpala, L.C., Gibson-Umeh, G.I., 2013. Physicochemical properties of mango seed flour. Nigerian Food J. 31 (1), 23
27. Oliveira, S.M.S., Falca˜o-Silva, V.S., Siqueira-Junior, J.P., Costa, M.J.C., de Melo Diniz, M.F.F., 2011. Modulation of drug resistance in Staphylococcus aureus by extract of mango (Mangifera indica) peel. Rev. Bras. Farmacog. 21, 190
193. Available from: https://doi.org/10.1590/ S0102-695X2011005000014. Palanivelu, P., 2006. Polygalacturonases: active site analyses and mechanism of action. Indian J. Biotechnol. 5, 148
162. Pandey, A., 1991. Aspects of fermenter design for solid-state fermentations. Process Biochem. 26, 335. Pandey, A., Radhakrishnan, S., 1992. Packed-bed column bioreactor for production of enzyme. Enzyme Microb. Technol. 14 (6), 486
488. Pandit, S.G., Vijayanand, P., Kulkarni, S.G., 2015. Pectic principles of mango peel from mango processing waste as influenced by microwave energy. LWT-Food Sci. Technol. 64 (2), 1010
1014. Patil, P.D., Gokhale, M.V., Chavan, N.S., 2014. Mango starch: its use and future prospects. Innov. J. Food Sci. 2 (1), 29
33. Pinto, G.A.S., Brito, E.S., Andrade, A.M.R., Fraga, S.L.P., Teixeira, R.B., 2005. Fermentac¸a˜o em estado so´lido: uma alternativa para o aproveitamento e valorizac¸a˜o de resı´duos agroindustriais tropicais, Embapa—Comunicado Te´cnico Online, vol. 102. Embrapa Agroindu´stria Tropical. Puravankara, D., Boghra, V., Sharma, R.S., 2000. Effect of antioxidant principles isolated from mango (Mangifera indica L.) seed kernels on oxidative stability of buffalo ghee (butter-fat). J. Sci. Food Agric. 80, 522
526. Rabobank Food and Agribusiness, 2018. World fruit map 2018: global trade still fruitful. Disposable in ,https://research.rabobank.com/far/en/sectors/ regional-food-agri/world_fruit_map_2018.html. (accessed January 2019.). Rajan, S., Suganya, H., Thirunalasundari, T., Jeeva, S., 2015. Antidiarrhoeal efficacy of Mangifera indica seed kernel on Swiss albino mice. Asian Pac. J. Trop. Med. 630
633. Ravani, A., Joshi, D., 2013. Mango and it’s by product utilization—a review. Energy (Kcal) 74, 44. Ravindran, V., Sivakanesan, R., 1996. The nutritive value of mango seed kernels for starting chicks. J. Sci. Food Agric. 71 (2), 245
250. Ridoutt, B.G., Juliano, P., Sanguansri, P., Sellahewa, J., 2010. The water footprint of food waste: case study of fresh mango in Australia. J. Clean. Prod. 18 (16-17), 1714
1721. Available from: https://doi.org/10.1016/j.jclepro.2010.07.011. ´ ., Herna´ndez, B.C., Montiel, L.M., Garrido, G.G., et al., 2006. Anti-allergic properties of Mangifera indica Rivera, D.G., Balmaseda, I.H., Leo´n, A.A L. extract (Vimang) and contribution of its glucosylxanthone mangiferin. J. Pharm. Pharmacol. 58 (3), 385
392. Sadiq, A.S., Elijah, I.R., Aroke, U.O., 2017. Extraction and assessment of physicochemical properties of rosigold mango (Mangifera indica) seed kernel oil for bioresin production. Arid Zone J. Eng. Technol. Environ. 13 (5), 643
654. Saleh, S., El-Maraghy, N., Reda, E., Barakat, W., 2014. Modulation of diabetes and dyslipidemia in diabetic insulin-resistant rats by mangiferin: role of adiponectin and TNF-α. An. Acad. Bras. Cieˆnc. 86 (4), 1935
1948. Sanon, H., Kanwe, A.B., Millogo, A., Ledin, I., 2013. Chemical composition, digestibility, and voluntary feed intake of mango residues by sheep. Trop. Anim. Health Prod. 45 (2), 665
669. Santos, T.C., Abreu, G.F., Rocha, T.J.H., Ferreira, A.N., Diniz, G.A., Franco, M., 2013. Produc¸a˜o e quantificac¸a˜o de celulases por meio da fermentac¸a˜o em estado so´lido de resı´duos agroindustriais. Sci. Agrar. Parana. 12 (2), 115
123. 2013. Sarmadi, B., Farhana, A., Muhajir, H., Nazamid, S., Azizah, A.H., Amin, I., 2012. Hypoglycemic effects of cocoa (Theobroma cacao L.) autolysates. Food Chem. 134 (2), 905
911. Schieber, A., Berardini, N., Carle, R., 2003. Identification of flavonol and xanthone glycosides from mango (Mangifera indica L. Cv. “Tommy Atkins”) peels by high-performance liquid chromatography-electrospray ionization mass spectrometry. J. Agric. Food Chem. 51 (17), 5006
5011. Sharma, K., Mahato, N., Cho, M.H., Lee, Y.R., 2017. Converting citrus wastes into value-added products: economic and environmentally friendly approaches. Nutrition 34, 29
46.

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Silva, G.A.S., Cavalcanti, M.T., Almeida, M.C.B.M., Arau´jo, A.S., Chinelate, G.C.B., Florentino, E.R., 2013. Use of starch of almond of Tommy Atkins mango as thickener for dairy beverages. Rev. Bras. Eng. Agrı´c. Ambient. 17 (12), 1326
1332. Silva, A.P.M., Oliveira, A.V., Pontes, S.M.A., Pereira, A.L.S., De-Sa´, M., Souza-Filho, M., et al., 2019. Mango kernel starch films as affected by starch nanocrystals and cellulose nanocrystals. Carbohydr. Polym. (in press). Singhania, R.R., Patel, A.K., Soccol, C.R., Pandey, A., 2009. Recent advances in solid-state fermentation. Biochem. Eng. J. 44, 13
18. Sirisakulwat, S., Nagel, A., Sruamsiri, P., Carle, R., Neidhart, S., 2008. Yield and quality of pectins extractable from the peels of Thai mango cultivars depending on fruit ripeness. J. Agric. Food Chem. 56 (22), 10727
10738. Sogi, D.S., Siddiq, M., Dolan, K.D., 2015. Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques. LWT-Food Sci. Technol. 62 (1), 564
568. Soong, Y.-Y., Barlow, P.J., 2004. Antioxidant activity and phenolic content of selected fruit seeds. Food Chem. 88 (3), 411
417. Sowmiya, S., Soundarapandian, P., Rajan, S., 2009. Bioactive studies of Mangifera indica against bacteria isolated from urine samples. Curr. Res. J. Biol. Sci. 1 (3), 139
143. Sruamsiri, S., Silman, P., 2009. Nutritive value and nutrient digestibility of ensiled mango by-products. Maejo Int. J. Sci. Technol. 3 (3), 371
378. Sudheer Kumar, Y., Varakumar, S., Reddy, O.V.S., 2010. Produc¸a˜o e otimizac¸a˜o de poligalacturonase de casca de manga (Mangifera indica L.) usando Fusarium moniliforme em fermentac¸a˜o em estado so´lido. World J. Microbiol. Biotechnol. 26, 1973
1980. Available from: https://doi.org/ 10.1007/s11274-010-0380-0. Torres-Leo´n, C., Rojas, R., Contreras-Esquivel, J.C., Serna-Cock, L., Belmares-Cerda, R.E., Aguilar, C.N., 2016. Mango seed: functional and nutritional properties. Trends Food Sci. Technol. 55, 109
117. Tsuji, H., Fukui, I., 2003. Enhanced thermal stability of poly (lactide) in the melt by enantiomeric polymer blending. Polymer 44 (10), 2891
2896. Vega-Vega, V., Brenda, A., Cruz-Valenzuela, M.R., Bernal-Mercado, A.T., Gustavo, A., Vargas, A., 2016. Antioxidant enrichment and antimicrobial protection of fresh-cut mango applying bioactive extracts from their seeds by-products. Food Nutr. Sci. 4, 197
203. Vijayarai, K., Sathiyagnanam, A.P., 2016. Experimental investigation of a diesel engine with methyl ester of mango seed oil and diesel blends. Alexandria Eng. J. 55 (1), 215
221.

Further reading Dos Santos, T.C., Abreu Filho, G., Rocha, T.J.H., Ferreira, A.N., Diniz, G.A., Franco, M., 2013. Produc¸a˜o e quantificac¸a˜o de celulases por meio da fermentac¸a˜o em estado so´lido de resı´duos agroindustriais. Sci. Agrar. Paran. 12 (2), 115
123. Madhave, A., Pushpalatha, P.B., 2002. Characterization of pectin extracted from different fruit wastes. J. Trop. Agric. 40, 53
55. Rehman, Z.U., Salariya, A.M., Habib, F., Shah, W.H., 2004. Utilization of mango peel as a source of pectin. J. Chem. Soc. Pak. 26, 73
76. Siddiq, M., Brecht, J.B., Sidhu, J.S., 2017. Handbook of Mango Fruit: Production, Postharvest Science, Processing Technology and Nutrition, first ed. John Wiley and Sons Ltd. Sudhakar, D.V., Maini, S.B., 2000. Isolation and characterization of mango peel pectins. J. Food Process. Preserv. 24 (3), 209
227. Tafazzal, H., Qaiser, M., Rashid, H., 1991. Extraction and evaluation of pectin from mango peel. Pak. J. Agric. Res. 12 (3), 213
216.

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Chapter 9

Passion fruit Pramote Khuwijitjaru1 and Khwanjai Klinchongkon2 1

Department of Food Technology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand, 2Department

of Innovation in Food Technology, College of Health Sciences, Christian University of Thailand, Nakhon Pathom, Thailand

Chapter Outline 9.1 9.2 9.3 9.4 9.5

Introduction Passion fruit production Pulp and juice processing Animal feeding Valuable components from peel 9.5.1 Drying of peel 9.5.2 Pectin and pectic oligosaccharides 9.5.3 Dietary fiber 9.5.4 Passion fruit peel flour 9.5.5 Passion fruit peel extract 9.6 Valuable components from seed

9.1

183 184 185 185 185 185 186 189 190 190 191

9.6.1 9.6.2 9.6.3 9.6.4

Drying of seed Seed oil Piceatannol and scirpusin B Other phenolic compounds and antioxidant activities 9.6.5 Seed protein 9.6.6 Antifungal protein 9.6.7 Seed fiber 9.7 Conclusion References

191 191 195 196 196 196 197 197 197

Introduction

Passion fruit, a well-known tropical fruit in the Passifloraceae family, is native to South America. Brazil is the largest passion fruit producer and market. Currently, however, the fruit is also cultivated in many regions for fresh consumption and various food industries worldwide. For example, in Thailand passion fruit was introduced in 1955 and cultivation and commercialization was successfully started in 1997 by the Royal Project Foundation. Now the fruit has become popular among consumers and plantations can be found in many areas of the country. Among the more than 50 2 60 species of edible fruit-bearing Passiflora species, purple (Passiflora edulis) and yellow (P. edulis f. flavicarpa) species (Fig. 9.1) are the most commonly grown for commercial purpose (Rodriguez-Amaya, 2012). Passion fruit is also known as “maracuja” from its Portuguese name and “purple granadilla” (for P. edulis) in some countries. The fruit comprises peel (or rind) at around 50% by weight (wet basis, w.b.) which is normally discarded as waste. In addition, for juice processing, seeds which account for about 10% by weight (w.b.), are also removed. Due to rising demand and the production of passion fruit for processed food industries, an increase in these major by-products is inevitable. Direct use of the peel and seed as animal feed is possible and is still practiced in areas where it is convenient to obtain the by-products. However, the extraction of high-value components from by-products is currently considered as a novel and more value-adding method for industrial by-products management. To date, however, only one review article on the utilization of by-products from passion fruit has been published (Correˆa et al., 2016). Although it can be seen from the Scopus database that the utilization of by-products from passion fruit began to receive attention from researchers from around 2005 (Fig. 9.2), several commercial products from these by-products are already on the market. This reflects the fact that these by-products are rich in a number of invaluable components. Fig. 9.2 also reveals that researchers from Brazil have been actively involved in research on the utilization of these by-products. In this chapter, therefore both commercial products including passion fruit seed oil and passion fruit seed extract together with their scientific studies and other strong potential uses of passion fruit peel and seed are summarized and presented. Examples of available commercial products are also given. Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00009-5 © 2020 Elsevier Inc. All rights reserved.

183

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Valorization of Fruit Processing By-products

FIGURE 9.1 Two major types of passion fruit: (A) P. edulis and (B) P. edulis f. flavicarpa.

FIGURE 9.2 (A) Number of documents per year and (B) number of documents by top 10 countries relating to the utilization of by-products from passion fruit indexed in Scopus (2000
18).

9.2

Passion fruit production

Passion fruit is commercially cultivated in many countries in tropical and subtropical regions. However, due to the fact that passion fruit production is still relatively low compared to other major crops, databases of fruit production and trading statistics usually combine passion fruit with other minor tropical fruits and make it is difficult to obtain the exact figures. For example, the EUROSTAT uses the commodity code 8109020 to refer to several fruits including fresh tamarinds, cashew apples, lychees, jackfruit, sapodilla plums, passion fruit, carambola, and pitahaya, while it is not possible to directly search for production of passion fruit from FAOSTAT database since it is included in the “Fruit, tropical fresh NES” (not elsewhere specified) category. To provide an update of the passion fruit production statistics, we collected available data from online sources and these are shown in Table 9.1. Interestingly, the FAO (Food and Agriculture Organization of the United Nations) just recently published a report on minor tropical fruit production in which passion fruit was also included (Altendorf, 2018). The document indicates that during 2015
17, the global production of passion fruit was around 1.5 million tonnes per annum. This number is relatively small when compared to that of major tropical fruit such as mango (“Mangoes, mangosteens, and guavas” category; 46.5 million tonnes in 2016) (FAOSTAT, 2018). Brazil, undoubtedly, is a leading producer of passion fruit (about 65% of global production) but most of the fruits are sold on the domestic market while Ecuador, Australia, and New Zealand are the most important exporters (Altendorf, 2018). Ecuador is the biggest passion fruit exporter with an estimated annual passion fruit production of about 150,000 tonnes according to an accessible online source (see citation in Table 9.1). A report by Griffith University indicated that the production volume of passion fruit in Australia reached more than 4500 tonnes in 2016 2 17 (Roberts et al., 2018). African countries such as Kenya and South Africa also produce and export the fruit (Gerbaud, 2013). CBI (2018) indicates that fresh passion fruits entering Europe are usually from African countries while pulp or concentrated juice is from Colombia, Ecuador, and Peru.

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TABLE 9.1 Production of passion fruit (tonne) in various countries. Country

Production (year)

Reference

Brazil Ecuador

948,100 (average 2015 2 17) 150,000 (2014)

Indonesia India Colombia Vietnam Thailand Australia New Zealand

114,600 (average 2015 2 17) 78,000 (2015 2 16) 60,000 (2016) 20,000 (average 2015 2 17) 8062 (2016) 4500 (2016 2 17) 125 (2016)

Altendorf (2018) Estimated value from http://www.freshplaza.com/article/2131719/good-yearfor-ecuadorian-passion-fruit Altendorf (2018) Government of India (2017) Ocampo et al. (2017) Altendorf (2018) Thai Department of Agricultural Extension (2017) Roberts et al. (2018) New Zealand Institute for Plant & Food Research (2016)

9.3

Pulp and juice processing

Apart from fresh fruit consumption, passion fruit is usually sold as frozen pulp, and frozen, pasteurized, sterilized, or concentrated juice which is also supplied to other food industries such as ice cream, sherbet, dairy products, and bakeries. The processing processes of passion fruit products have been described by some authors (Rodriguez-Amaya, 2012; Occen˜a-Po, 2006). The current industrial-scale processing of the fruit starts with initial washing of the whole fruits in a washing tank. Sorting of damaged fruits is then normally done by workers. A brushing machine can be used to further clean the outside of the fruit. Cleaned fruits are then processed for juice extraction. The juice extraction system can be a three-stage system, as described by Rodriguez-Amaya (2012), which comprises a disk cutter, a perforated cylinder with beaters for separating pulp and seed from peel, and two pulp finishing machines. Bertuzzi Food Processing, an Italian company provides a dedicated juice extraction system for passion fruit. According to the company website (www.bertuzzi.it), passion fruit is squeezed through two cylinders; one made from stainless steel with a special shape and the second one made from rubber. Fratelli Indelicato, another Italian company (www.indelicatotech.com), also manufactures a passion fruit extraction machine with two stainless steel cylinders with a horizontal knife to cut the fruit before the fruit is squeezed. Frozen fruit pulp with seed can be processed from the product in this step or a pulp finisher is used to separate juice from pulp and seeds. Because the moisture contents of passion fruit peel and seed are very high (88% w.b. and 30% 2 40%, respectively), these by-products must be used immediately or a drying step is necessary to prevent microbial spoilage.

9.4

Animal feeding

Using peel and seed for animal feeding can be conveniently practiced in areas near the juice processing factory. Apart from feeding cattle, which is currently the most common use of peel, passion fruit seed can be mixed in the feed by up to 5% for hens and broilers (Zanetti et al., 2016, 2017), while seed meal may be used up to 16% in the diet for swine (Fachinello et al., 2015).

9.5 9.5.1

Valuable components from peel Drying of peel

Passion fruit peel, which represents about half of the whole fruit mass, is a low-cost by-product generated during passion fruit juice processing. It is usually used as animal feed supplement. However, because more than 80% of passion fruit peel is water, the peel cannot be kept over the long term. Drying of passion fruit peel can extend its shelf life, but the drying process must be careful since it can affect bioactive compounds in the peel. Cut small pieces of peel can be dried using a hot-air dryer at 50 C
60 C and air velocity of 2.4
3.0 m/s within 2.5
4.8 h and these drying conditions do not affect the physicochemical properties of the peel (Duarte et al., 2017), and enable the retention of a high amount of pectin similar to a freeze-drying process because the temperature is low (Silva et al., 2017). Other novel drying techniques have been evaluated for the drying of passion fruit peel as well. Ultrasound-assisted drying using a piezoelectric transducer that provides 21.8 kHz ultrasonic wave with a power of 30.8 kW/m3 could reduce the drying time because it

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TABLE 9.2 Chemical composition (%) of dried passion fruit peel. Composition

P. edulisa

P. edulis f. flavicarpab

P. edulis f. flavicarpac

P. edulis f. flavicarpad

Moisture content (w.b.) Protein (d.b.) Crude fat (d.b.) Ash (d.b.) Carbohydrate (d.b.)

9.4 4.3 0.4 7.6 87.7

4.3 3.7 0.7 7.4 88.1

7.4 5.3 1.3 6.0 87.5

4.9 4.6 0.6 6.4 88.3

a

Source: Klinchongkon, K., Khuwijitjaru, P., Wiboonsirikul, J., Adachi, S., 2017c. Extraction of oligosaccharides from passion fruit peel by subcritical water treatment. J. Food Process Eng. 40, e12269. Source: Canteri, M.H., Scheer, A., Petkowicz, C., Ginies, C., Renard, C., Wosiacki, G., 2010a. Physicochemical composition of the yellow passion fruit pericarp fractions and respective pectic substances. J. Food Nutr. Res. 49, 113
122. c Source: Macagnan, F.T., Santos, L.R.D., Roberto, B.S., de Moura, F.A., Bizzani, M., da Silva, L.P., 2015. Biological properties of apple pomace, orange bagasse and passion fruit peel as alternative sources of dietary fibre. Bioact. Carbohydr. Diet. Fibre, 6, 1
6. d Source: Herna´ndez-Santos, B., Vivar-Vera, M.D.L.A´., Rodrı´guez-Miranda, J., Herman-Lara, E., Torruco-Uco, J.G., Acevedo-Vendrell, O., et al., 2015. Dietary fibre and antioxidant compounds in passion fruit (Passiflora edulis f. flavicarpa) peel and depectinised peel waste. Int. J. Food Sci. Technol. 50, 268
274. b

increases both the effective diffusivity and the mass transfer coefficient, especially in the drying processes at 40 C
50 C. Therefore the technique also reduced the loss of total phenolic content and antioxidant activity of dried passion fruit peel (do Nascimento et al., 2016). It was reported that infrared and microwave drying techniques increased phenolics and flavonoids in passion fruit peel, but reduced the pectin content because of pectin degradation in the peel (Silva et al., 2017). However, the increase of phenolic compounds after drying of plants has been often reported. In addition, some authors suggested that passion fruit peel should be blanched in boiling water before drying. Although the process did not improve the water migration during drying of the peel as well as a quality and a quantity of the pectin, it could inactivate pectin degrading enzymes (Kulkarni and Vijayanand, 2010; Duarte et al., 2017; Canteri et al., 2010a). The final moisture content of passion fruit peel should be reduced to around 10% or lower to prevent microbial growth. The proximate compositions of dried passion fruit peel are shown in Table 9.2, indicating that carbohydrate is the main constituent of peel. The important carbohydrate might be pectin which can be found at 25%, while hemicellulose and cellulose can be found at 12% and 42%, respectively (Yapo and Koffi, 2008). Analysis of the hemicellulose fraction also indicated that it comprises mainly xyloglucans (90%) and a small amount of glucomannans (10%).

9.5.2

Pectin and pectic oligosaccharides

Pectin is generally found in plant cell walls together with cellulose and hemicellulose. It is a complex polysaccharide rich in galacturonic acid units used as gelling, thickening, and stabilizing agents not only in the food sector, but also in pharmaceutical products and cosmetics (Brejnholt, 2010). Pectic oligosaccharides are partially hydrolyzed pectin chains, which show many beneficial properties for human health (Gullon et al., 2013). Pectin is found in passion fruit peel from a few percentages to approximately 25% (w/w) of the total peel mass (Bussolo de Souza et al., 2018; Kulkarni and Vijayanand, 2010; Contreras-Esquivel et al., 2010). Compared with other commercial pectin sources, such as citrus peel (20% 2 35%) and apple pomace (10% 2 15%), passion fruit peel is one of several agromaterial by-products that show strong potential to be used as new sources for pectin production. Pectin consists of homogalacturonan as the main chain and rhamnogalacturonan I and rhamnogalacturonan II as the side chains. The main chain is a linear homopolymer of (1-4)-α-linked-D-galacturonic acid and is estimated to contain around 100
200 galacturonic acid units (Brejnholt, 2010). The carboxyl groups of the galacturonic acids are partially methyl esterified which provides the molecules with a certain degree of hydrophobicity (Trujillo-Ramı´rez et al., 2018). Moreover, the amount of the methoxyl group is also used for classification of pectin into high methoxyl (HM) and low methoxyl (LM) pectins. The pectin side chain, rhamnogalacturonan I, consists of repeating units of the disaccharide (1-2)-α-L-rhamnose-(1-4)-α-D-galacturonic acid as a backbone and 20%
80% of rhamnose monomers are branched with side chains of neutral oligosaccharides which mostly are arabino- and galactooligosaccharides (Schols and Voragen, 2002). Rhamnogalacturonan II also has a side chain structure, but is different from the prior structure since its backbone is composed of homogalacturonan. The latter structure is more complex than the former because it usually consists of different polymeric side chains and rare sugars (Brejnholt, 2010).

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9.5.2.1 Physical and chemical characteristics The color of passion fruit pectin depends on the types of pigments contained in raw material, particularly the outer shell of the peel (exocarp). Unpurified pectin from purple passion fruit peel is pale pink which results from pigments from the peel, as shown in Fig. 9.3. However, the pectin is pale yellow when the exocarp is removed before extraction or when the pectin comes from yellow passion fruit peel. Kidøy et al. (1997) reported that cyanidin 3-glucoside, which is an anthocyanin, is the most abundance pigment compound found in purple passion fruit peel, whereas carotenoids might be responsible for the yellow color in yellow passion fruit peel (Oliveira et al., 2016).

9.5.2.2 Extraction Conventional acid extraction A conventional method for pectin extraction is a hot aqueous acid extraction followed by precipitation in an organic solvent, especially ethanol. A possible process for the extraction of pectin from passion fruit peel is shown in Fig. 9.4. The extraction can be accomplished by using several types of acid solution including hydrochloric acid (Kulkarni and

FIGURE 9.3 Passion fruit pectin (unpurified) after alcohol precipitation: (A) purple passion fruit peel pectin and (B) yellow passion fruit peel pectin.

FIGURE 9.4 Flow chart for passion fruit pectin extraction by the conventional method.

188

Valorization of Fruit Processing By-products

Vijayanand, 2010), nitric acid (Canteri et al., 2010a), citric acid (Yapo, 2009b), tartaric acid, and acetic acid (Seixas et al., 2014). The ratio of peel sample and solvent must be considered. They are usually in a range of 1:25
1:50 (w/v). For ethanol precipitation, double or triple volumes of ethanol are generally used at ambient or 4 C (Yapo, 2009b; Liew et al., 2014; Pinheiro et al., 2008; Canteri et al., 2010a). Kulkarni and Vijayanand (2010) obtained 14.8% (w/w) of pectin yield by using hydrochloric acid (pH 2) extraction at 98.7 C for 60 min. The extraction was performed with 1:30 (w/v) of peel to acid solution ratio. The obtained pectin was HM pectin because the degree of esterification (DE) was higher than 50%. The pectin was composed of 88% (w/w) of galacturonic acid with good gelling capacity. Canteri et al. (2010a) obtained a similar yield value, approximately 13.6% of pectic substance, when only the mesocarp of passion fruit peel was extracted using 50 mM nitric acid solution at 80 C for 20 min. The obtained pectin was also HM pectin (DE 5 79%) with high viscosity that is suitable for using as a stabilizer and thickener. To avoid using strong acids, Yapo (2009b) compared the extractability of lemon juice and citric acid on passion fruit pectin production. Both solutions resulted in HM pectin but the extraction with lemon juice was more efficient than citric acid since it gave higher pectin yield (10.8%, w/w) and higher galacturonic acid content (78.3%, w/w) than citric acid extraction method. According to the FAO and EU regulation, pectin must contain at least 65% galacturonic acid in order to be able to be commercialized as pectin (Brejnholt, 2010). Therefore it indicates that all passion fruit pectins obtained from the above studies are possible to be used as commercial pectin. Although most of the acid extraction conditions resulted in HM pectin, LM pectin from passion fruit peel was also obtained from nitric acid extraction as reported by Yapo and Koffi (2006). This may be because the passion fruit peel powder was pretreated by ethanolic solution at 80 C for 45 min before pectin extraction, resulting in deesterification of pectin. The type and concentration of acid are the most important factors affecting the DE, molecular mass, gel strength, and sugar composition of passion fruit peel pectin (as shown in Table 9.3) (Pinheiro et al., 2008; Seixas et al., 2014; Yapo, 2009a). It was shown by Seixas et al. (2014) that, although extractions were performed under the same conditions, the passion fruit pectin obtained from tartaric acid had lower molecular weight than those obtained from nitric and citric acids. Molecular weights, gel strengths, and DEs of passion fruit peel pectins extracted by citric, nitric, and sulfuric acids were in the ranges of 100a250 kDa, 127a179 SAG, and 29%a73%, respectively. All these pectins could form gels under high soluble solids content. Although the highest pectin yield was obtained from nitric acid extraction, the pectin extracted from citric acid was firmer than the others. This may be because of higher DE and molecular weight. However, passion fruit peel pectin extracted by 30 mM citric acid exhibited gelling properties, such as lower gel-setting time, similar to lemon pectin extracted by nitric acid (pH 1.4) at 75 C for 2 h (Yapo, 2009a).

9.5.2.3 Microwave- and ultrasound-assisted extractions Other novel extraction techniques, such as microwave- and ultrasound-assisted extractions, to enhance pectin extraction also have been evaluated. Microwave heating promoted an increase of porosity of passion fruit peel and therefore the pectin was easily released. The highest yield (13%) of pectin was obtained from the extraction at 628 W for 9 min. TABLE 9.3 Monosaccharide composition (%) and DE of passion fruit pectin extracted by several types of acids. Monosaccharide

Acetic acida

Tartaric acida

Nitric acidb

Citric acidc

Hydrochloric acidd

Rhamnose Fucose Arabinose Xylose Mannose Galactose Glucose Uronic acid DE

4.0 0.5 9.5 2.5 1.8 6.8 12.4 62.5 64.6

5.9 0.6 8.1 2.5 1.7 9.2 13.5 58.5 50

0.4 0.0 ND ND ND 1.1 1.6 68.1 80

2.2 ND 3.9 1.5 ND 4.1 , 0.5 71.2 52

5.10 0.0 2.01 1.84 0.84 8.12 14.48 51.30 84.17

a

Source: Seixas, F.L., Fukuda, D.L., Turbiani, F.R.B., Garcia, P.S., Petkowicz, C.L.D., Jagadevan, S., et al. 2014. Extraction of pectin from passion fruit peel (Passiflora edulis f. flavicarpa) by microwave-induced heating. Food Hydrocoll. 38, 186
192. b Source: Canteri, M.H., Scheer, A., Petkowicz, C., Ginies, C., Renard, C., Wosiacki, G. 2010. Physicochemical composition of the yellow passion fruit pericarp fractions and respective pectic substances. J. Food Nutr. Res., 49, 113
122. c Source: Yapo, B.M., 2009b. Lemon juice improves the extractability and quality characteristics of pectin from yellow passion fruit by-product as compared with commercial citric acid extractant. Bioresour. Technol., 100, 3147
3151. d Source: de Moura, F.A., Macagnan, F.T., Dos Santos, L.R., Bizzani, M., De Oliveira Petkowicz, C.L., Da Silva, L.P., 2017. Characterization and physicochemical properties of pectins extracted from agroindustrial by-products. J. Food Sci. Technol. 54, 3111
3117.

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Ultrasound-assisted extraction has been widely reported to improve extraction performance of various bioactive compounds due to the cavitation phenomena (Chemat et al., 2017). The extraction by ultrasound-assisted method using a power intensity of 644 W/cm2 at 85 C for 10 min could almost double the passion fruit pectin yield compared with a conventional extraction. The highest yield, galacturonic acid content, and DE of the obtained pectin were about 13%, 67%, and 60%, respectively (Seixas et al., 2014; de Oliveira et al., 2016).

9.5.2.4 Subcritical water extraction Subcritical water is usually defined as liquid water in a temperature range of 100 C
374 C under high-pressure conditions. It is classified as a green technology for the extraction of bioactive compounds because only water is used as an extraction solvent (Khuwijitjaru, 2016). Subcritical water promotes the increase of hydronium ions which therefore act as an acidic medium for the hydrolysis reaction. This technology has been studied for the extraction of pectin from passion fruit peel. The extraction at 150 C within 4.5 min or 175 C within 5.5 min gave the highest yield of 21% with 65% of galacturonic acid (Klinchongkon et al., 2017c). The yield is similar to the yield of citrus peel pectin (22%), but higher than the yield of apple pomace pectin (17%) obtained from subcritical water extraction at 120 C and 150 C, respectively (Wang et al., 2014). Because of the high degree of hydrolysis occurring during the extraction in subcritical water, the molecular weight of pectin from this approach is typically lower than conventional acid-extracted pectin and therefore the pectin exhibits lower firmness, cohesiveness, consistency, and viscosity index (Wang and Lu¨, 2014). The degradation kinetics of passion fruit pectin under subcritical water conditions were evaluated by Klinchongkon et al. (2017b). The size of pectin was rapidly reduced at 140 C and about 97% molecular size reduction was found when the pectin was treated at 160 C for 5 min. Therefore subcritical water extraction of pectin may be a convenient way to prepare such low molecular weight pectin. Low molecular weight pectin usually showed better prebiotic properties than high molecular pectin. In addition, low molecular weight pectin can also be used to improve the emulsifying properties of protein such as whey protein at a pH near the isoelectric point by conjugation reaction (Klinchongkon et al., 2019). Ethanol (10%a30%, v/v) was also added in the subcritical water extraction of passion fruit peel pectin as a cosolvent. The addition of ethanol in the extraction was not advantageous for the pectin yield, but increased the antioxidant and total phenolic contents (Klinchongkon et al., 2017a).

9.5.2.5 Enzymatic extraction The enzymatic extraction method was also investigated for pectin extraction. This extraction method is also environmentally friendly because it is usually conducted at low temperature. Liew et al. (2016) used commercial cellulase (celluclast 1.5 L) for pectin extraction from yellow passion fruit and found that under optimal conditions, the pectin yield was not different to that of acid extraction but the enzymatic method showed a higher capability to give HM pectin. Crude protopectinase produced from Geotrichum klebahnii was applied for passion fruit pectin extraction (Vasco-Correa and Zapata, 2017). Protopectinase can hydrolyze protopectin to give soluble pectin. The enzymatic process operated using 30 U/mL of protopectinase, at pH 3.0 and 37 C gave a 40% higher pectin yield than that obtained from the conventional method. The pectin contained 85% of galacturonic acid and 68% of DE, similar to commercial citrus pectin. Moreover, this condition was successfully scaled-up to bench scale (7 L stirred-tank).

9.5.3

Dietary fiber

Dietary fiber is an essential component of a healthy diet. Dietary fiber can be divided into soluble and insoluble dietary fibers, based on solubility in water. Pectin is classified as a soluble fiber, whereas cellulose and some hemicelluloses are insoluble fibers. In recent years, the utilization of by-products from agricultural industries for producing dietary fiber has been gaining much attentions. In fact several commercial dietary fiber products are produced from byproducts. Passion fruit peel is a good source for dietary fiber. It has been reported that the peel contains total dietary fiber in the range of 63%a72% of dry peel (Canteri et al., 2010a; Macagnan et al., 2015; Lo´pez-Vargas et al., 2013). Among the many carbohydrate components of the fiber, pectin is approximately 19%a25% (Contreras-Esquivel et al., 2010; Bussolo de Souza et al., 2018), while insoluble materials are approximately 40%a52% of dry passion fruit fiber (Macagnan et al., 2015; Martinez et al., 2012; Lo´pez-Vargas et al., 2013). Passion fruit peel fiber has a pH of 4.36 which is similar to that of pomegranate bagasse fiber (Lo´pez-Vargas et al., 2013; Viuda-Martos et al., 2012). The fiber had water-holding (13.5 g water/g fiber) and swelling (7.2 mL water/g sample) capacities higher than those obtained from pineapple, guava, and mango (Martinez et al., 2012). Passion fruit peel fiber showed significantly slower

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absorption of glucose in both in vitro and in vivo experiments (Bussolo de Souza et al., 2018; Macagnan et al., 2015), promoted a significant reduction of serum triglycerides levels and hepatic cholesterol in rats, as well as improved the intestinal tract of animals, as determined by reduced fecal pH and increased fecal moisture (Macagnan et al., 2015).

9.5.4

Passion fruit peel flour

A simple method of passion fruit peel utilization as a food ingredient is its use in its powder form, which is commonly called passion fruit peel flour. The process for preparing passion fruit peel flour is simple. After cutting into small pieces, the peel can be dried at 50 C and milled to fine powder (Coelho et al., 2017). Alves et al. (2018) dried the peel at 60 C for 24 h before milling it into flour with particle size in the range 853 2 1200 μm. Passion fruit flour is used primarily as a source of dietary fiber. It can be directly mixed as an ingredient into food formulas. It was reported that the flour can replace commercial hydrocolloids in mayonnaise and passion fruit nectars since it can act as stabilizing agent, emulsifier, thickener, and gelling agent (Coelho et al., 2017). The addition of dietary fiber is challenging since the fiber might affect the color and texture of products. The addition of passion fruit peel flour (1 g/100 g product) significantly increased the apparent viscosities of yoghurt and gruel made from rice flour and soy milk (Espirito-Santo et al., 2014; Espı´rito-Santo et al., 2013). On the other hand, the addition of the flour at 2.5% improved cooking yield, moisture, and fat retentions of pork burger (Lo´pez-Vargas et al., 2014). Casarotti et al. (2018) compared three fruit byproduct flours including guava, orange, and passion fruit with particle size smaller than 42 μm by adding each flour at 1% in fermented oat beverage, rice beverage, and goat milk. They found that adding fruit flours did not affect the fermentation kinetics of fermented oat beverage and goat milk but slowed down the fermentation of rice beverage. Nevertheless, passion fruit flour helps to protect probiotic bacteria (Lactobacillus casei LC-1) in simulated gastrointestinal tests. There are some reports of clinical trials that investigated the effect of passion fruit peel flour on health benefits. de Queiroz et al. (2012) reported that ingestion of 30 g a day of the yellow passion fruit peel flour for 8 weeks significantly reduced insulin resistance in people with type 2 diabetes. However, a recent clinical trial with ingestion of 12 g of passion fruit peel flour, three times daily for 8 weeks indicated that the flour did not improve the glycemic control of people with type 2 diabetes (de Arau´jo et al., 2017). Therefore it seems that more studies are needed to prove the effect of passion fruit rind flour on glycemic control of type 2 diabetic patients. In Brazil many manufacturers are offering yellow passion fruit peel flour as a fiber-rich flour. For example, Macc¸a˜ Desidratados e Congelados (www.macca.com.br) is selling passion fruit flour along with other fruit and vegetable flours. Pazze Food Industry also lists yellow passion fruit peel flour as an upcoming product on its website (www.pazze.com.br). In nonfood applications, passion fruit peel flour was studied as a glucose-rich (45.5%) substrate for enzyme production by the fermentation process. It could enhance β-glucosidases production by Penicillium verruculosum by 5.7-folds (Almeida et al., 2015). Passion fruit peel was also used as a sole substrate for Aspergillus flavus to produce xylanase which is stable at 55 C
60 C and over a wide range of pH (Martins et al., 2018). Another possible application is the use of passion fruit peel as a bioadsorbent. In the study by Pavan et al. (2008), yellow passion fruit peel was dried and ground and the particle with size less than 250 μm was washed with water and dried again before use for the removal of methylene blue from an aqueous solution.

9.5.5

Passion fruit peel extract

There have been a number of attempts to search for high-value, health-beneficial compounds in passion fruit peel. Positive effects of passion fruit peel extract on osteoarthritis, asthma, and hypertension were emphasized (Cordova et al., 2013). Polysaccharides (34.9% yield) obtained from hot-water extraction of passion fruit peel flour showed an in vivo but not in vitro inhibition effect on tumor cells which might indicate immunostimulating properties (Silva et al., 2012). The extraction conditions resembled those of pectin extraction but without acid, and the obtained polysaccharide contained mainly linear homogalacturonan (HG) and neutral sugar-branched rhamnogalactorunan-1 (RG-1) with higher RG-1 than HG. The oral intake of purple passion fruit peel extract in patients with knee osteoarthritis has been studied and it was found to have a high potential for reducing the symptoms (Farid et al., 2010). In another study, Zibadi et al. (2007) also reported that the extract may be used as an alternative treatment to hypertensive patients. The extracts used in both studies were obtained by immersion of the fruit peel in water at 60 C, stirring for 5 min, and soaking overnight at 22 C. The crude extract was then processed by column filtration to increase the concentrations of flavonoids, phenolic

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acids, and anthocyanins (Zibadi et al., 2007). HPLC analysis indicated that the major compounds in the extract were cyanidin 3-O-glucoside, quercetin 3-O-glucoside, and edulilic acid, while other minor components were catechin, epicatechin, kaempferol-3-O-glucoside, kamepferol, luteolin-8-C-neohesperoside, luteolin-8-C-digitoxoside, protocatechuic acid, quercetin, and prunasin acid. Originally found in P. edulis, edulilic acid was first isolated and identified by Foo et al. (2005). Lewis et al. (2013) also extracted passion fruit peel using an immersion in water at room temperature for 16
24 h. Edulilic acid and anthocyanin fraction were also separated from the extract and tested with spontaneously hypertensive rats. It was found that the extract showed an antihypertensive effect and both edulilic acid and anthocyanin fraction could be the active compounds. The use of passion fruit peel extract which contains more than 1% edulilic acid to lower blood pressure and serum nitric oxide level has been patented (Foo et al., 2005). Using methanolic extract of fresh peel of P. edulis to orally administer spontaneously hypertensive rat also resulted in a significant lowering of systolic blood pressure (Ichimura et al., 2006). The authors concluded that, however, the antihypertensive effect of the extract might be mainly from the high content of γ-aminobutyric acid and partially from luteolin and luteolin-6-C-glucoside and other phenolic compounds which were found at much lower concentrations. Zeraik et al. (2011) attempted to extract flavonoid from peel of P. edulis f. flavicarpa using methanol and identified isoorientin, a C-glucoside flavone, as a major active flavonoid which contributed to the high antioxidant activity of the extract and showed potential for the use of the rind extract for antiinflammatory purposes. To enhance the extraction of flavonoids, sequential pressurized solvent extraction using 60% (v/v) ethanol at 80 C resulted in total phenolic content of 4.67 g gallic acid equivalent (GAE)/kg peel. The two major phenolic compounds found were orientin-7-O-glucoside of 1.57 g/kg peel, and luteolin-6-C-glucoside of 2.44 g/kg peel (de Souza et al., 2018). While the practical usage of passion fruit peel extract for curing or preventing certain diseases is still not approved and needs more study, NOF Corporation (Japan) (www.nof.co.jp) is currently offering a passion fruit peel extract as an ingredient for cosmetics. According to the company’s website, the extract is obtained by extraction with 1,3-butylene glycol aqueous solution. The company claims that the extract contains various phenolic compounds, such as luteolin glucoside, which has antioxidant activity and has an inhibitory effect on the biosynthesis of endothelin-1 and therefore shows a skin-whitening effect.

9.6 9.6.1

Valuable components from seed Drying of seed

The weight of seeds is about 10% of the total fruit and they contain an initial moisture content of around 30% (w.b.) (Santos et al., 2018), hence drying is necessary to prevent spoilage. Passion fruit seed can be dried by air-drying within ´ leos 2 days to lower the moisture content to 10.80% (Liu et al., 2008). According to Oliveira et al. (2017), Extrair O  Naturais, one of the cold-pressed seed oil manufacturers in Brazil uses a rotational drier at 60 C to dry the seed to the moisture content of 8.5% while Sı´tio do Bello company dried the seed bagasse with a circular oven at 60 C for 30 h to obtain the final moisture content of 3.5% dry basis (Vigano´ et al., 2016). Drying kinetics studied at 40 C, 50 C, and 60 C in a convective dryer showed that moisture content in seed can be removed to reach a constant weight within a rather short time of 158, 75, and 42 min, respectively (Va´quiro et al., 2016). Proximate compositions of dried passion fruit seed from the two important species (P. edulis and P. edulis f. flavicarpa) together with a hybrid variety Tainung No. 1 from Taiwan, which is widely cultivated in China, are shown in Table 9.4. As can be expected, carbohydrate is the largest part of the seed followed by fat and protein.

9.6.2

Seed oil

Passion fruit seed oil, also known as maracuja oil, is a product from passion fruit seed that has been widely commercialized as a pure oil for use as a massage oil or for cosmetic purposes. It is also used as a component in hair shampoo, soap, and moisturizing products. The oil content in the seed of passion fruit is usually in the range of 18% 2 28% by weight (Nyanzi et al., 2005; Liu et al., 2008). Malacrida and Jorge (2012) reported the oil yield of 30.39% from P. edulis f. flavicarpa which is the most widely cultivated in Brazil. This indicates that passion fruit seed is a good source of oil when compared to soybean (23%) or grape seed (15%) (Bockisch, 1998). Because the seed is normally dried to 5% 2 10% and the oil yield can be roughly approximated to 25%, it can be estimated that 1000 kg of fresh passion fruit can produce approximately 20 kg of seed oil.

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Valorization of Fruit Processing By-products

TABLE 9.4 Chemical composition (% w.b.) of dried passion fruit seeds. Composition

P. edulisa

P. edulisb

P. edulis f. flavicarpac

Tainung No. 1d

Moisture content Protein Crude fat Ash Carbohydrate

3.5 17.7 24.2 6.6 51.5

7.4 16.3 28.9 1.7 45.8

7.4 12.2 30.4 1.3 48.7

6.6 8.3 24.5 1.3 65.9*

*Calculated from total dietary fiber and carbohydrate contents. a Source: Barrales, F.M., Rezende, C.A., Martı´nez, J., 2015. Supercritical CO2 extraction of passion fruit (Passiflora edulis sp.) seed oil assisted by ultrasound. J. Supercrit. Fluids 104, 183
192. b Source: de Santana, F.C., de Oliveira Torres, L.R., Shinagawa, F.B., de Oliveira e Silva, A.M., Yoshime, L.T., de Melo, I.L.P., et al., 2017. Optimization of the antioxidant polyphenolic compounds extraction of yellow passion fruit seeds (Passiflora edulis Sims) by response surface methodology. J. Food Sci. Technol. 54, 3552
3561. c Source: Malacrida, C.R., Jorge, N., 2012. Yellow passion fruit seed oil (Passiflora edulis f. flavicarpa): physical and chemical characteristics. Braz. Arch. Biol. Technol. 55, 127
134. d Source: Chau, C.F., Huang, Y.L., 2004. Characterization of passion fruit seed fibres—a potential fibre source. Food Chem. 85, 189
194.

TABLE 9.5 Physical properties of unrefined passion fruit seed oil. Properties

P. edulis f. flavicarpaa

P. edulis f. flavicarpab

Tainung No. 1c

Extraction method Color Specific gravity

Soxhlet with hexane Almost colorless 0.90836 (20 C), 0.89453 (40 C) 1.4660 (40 C) 1.50

130.98

Soxhlet with petroleum ether



Supercritical carbon dioxide Golden-orange 0.9171 (20 C)

1.4682 (40 C) 2.35 1.46 190.7 128.0

1.4680 (20 C) 2.36 1.37 187.4 129.3

Refractive index Acid value (mg KOH/g) Peroxide value (mmol/kg) Saponification value (KOH mg/g) Iodine value (g I2/100 g oil)

a Source: Pereira, M.G., Maciel, G.M., Haminiuk, C.W.I., Bach, F., Hamerski, F., de Paula Scheer, A., et al., 2018. Effect of extraction process on composition, antioxidant and antibacterial activity of oil from yellow passion fruit (Passiflora edulis var. flavicarpa) seeds. Waste Biomass Valoriz. doi:10.1007/s12649-018-0269-y. b Source: Malacrida, C.R., Jorge, N., 2012. Yellow passion fruit seed oil (Passiflora edulis f. flavicarpa): physical and chemical characteristics. Braz. Arch. Biol. Technol. 55, 127
134. c Source: Liu, S., Yang, F., Zhang, C., Ji, H., Hong, P., Deng, C., 2009. Optimization of process parameters for supercritical carbon dioxide extraction of Passiflora seed oil by response surface methodology. J. Supercrit. Fluids 48, 9
14.

9.6.2.1 Physical and chemical characteristics Passion fruit seed oil may show different colors depending on the extraction and refining method, from golden orange, bright yellow, pale yellow, to almost colorless. Sohxlet extraction with hexane gives a colorless oil while supercritical carbon dioxide extraction gives a golden-orange color (Liu et al., 2009; Pereira et al., 2018). The oil is liquid at room temperature with a characteristic aroma. Important physical and chemical properties of seed oil are shown in Table 9.5. The solvent-extracted oils without refining show relatively low peroxide values (1.37 2 1.46 mmol/kg or equivalent to 0.69 2 0.73 mequiv./kg) compared to the maximum levels of 10 and 15 mequiv./kg for refined oil and cold-pressed oil, respectively. The acid values are higher than the maximum limit for refined oil (0.6 mg potassium hydroxide (KOH) /g) but below the limit for cold-pressed and virgin oil (4.0 mg KOH/g) (Codex Alimentarius Commission, 2017). The oxidative stability of yellow passion fruit seed oil studied by Rancimat test at 100 C with air flow at 20 L/h was found to be 7.89 h which was below common edible oils, such as soy and sunflower oils (Malacrida and Jorge, 2012). It should be noted that even though some authors suggested that the physical and chemical properties of passion fruit seed oil meets the quality criteria of edible oil (Malacrida and Jorge, 2012; Liu et al., 2008), the direct use of passion fruit seed oil as an edible oil has never been reported.

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9.6.2.2 Fatty acid compositions The major fatty acid components of passion fruit seed oil are shown in Table 9.6. These data are from the oils extracted by different extraction methods. Typically the oil is very high in unsaturated fatty acids (84% 2 89%) including linoleic acid (70%), oleic acid (15%), and a small amount of linolenic acid, while palmitic acid (10%) and stearic acid (2%) are the main saturated fatty acids. Other fatty acids such as C14:0, C20:0, and C22:0 were also found in small amounts (Barrales et al., 2015; de Santana et al., 2017). The fatty acid composition of passion fruit seed oil is quite similar to that of grape seed oil or safflower seed oil (Codex Alimentarius Commission, 2017).

9.6.2.3 Unsaponifiable components Similar to other oils from fruit seeds, passion fruit seed oil contains unsaponifiable components including tocols (tocopherols and tocotrienols), phytosterols, squalene, carotenoids, and other phenolic compounds (da Silva and Jorge, 2014; de Santana et al., 2015). Seed oils from four species of passion fruit cultivated in Brazil contained total phytosterols in the range 174.96 2 227.55 mg/100 g oil, vitamin E (as α-tocopherol) in the range 77.57 2 215.30 mg/100 g oil, total carotenoids in the range 50.87 2 115.44 mg β-carotene/100 g oil, and total phenolic content (TPC) in the range 0.94 2 15.22 g GAE/100 g oil (de Santana et al., 2015). da Silva and Jorge (2014) determined the compounds in the lipid fraction of several seeds obtained by chloroform:methanol:water (2:1:0.8, v/v/v) extraction and found that passion fruit seed oil contained 281.1 mg/kg of total tocopherols, 274.7 mg/100 g of phytosterols, 92.8 mg/kg of phenolic compounds (by HPLC), 262.3 mg GAE/kg of TPC, and 6.7 μg β-carotene/g of total carotenoids. Supercritical carbon dioxide extraction gave higher unsaponifiable fraction (2.86%) than solvent extraction (0.90%) (Liu et al., 2008).

9.6.2.4 Extraction Cold-pressing Lipid components in passion fruit seed can be extracted by either mechanical or solvent extraction. Cold-pressed oil can be efficiently expressed using a relatively simple machine. In the cosmetics market, cold-pressing gives the oil product that may attract consumers for its chemical-free process. However, it should be noted that although the coldpressed oil has been commercially produced, technical information on the method is relatively scarce. The seed obtained from juice processing should be cleaned to remove residue pulp and mucilage by stirring in water. Drying of seed at 50 C for 6 h was reported to be optimal (Mattos de Paula et al., 2015) before pressing with an expeller TABLE 9.6 Oil content and fatty acid composition of some passion fruit seed samples. Components

P. edulisa

P. edulisb

P. edulis f. flavicarpaa

P. edulis f. flavicarpac

Tainung No. 1d

Extraction method Oil yield (%) C16:0 palmitic C18:0 stearic C18:1 oleic C18:2 linoleic C18:3 linolenic Total unsaturated

Soxhlet with petroleum ether 18.5 8.8

Soxhlet with hexane 24.7 11.5

Soxhlet with petroleum ether 20.6 11.0

Soxhlet with hexane 26.1 10.2

Supercritical carbon dioxide 25.8 8.6

2.2 13.6 74.3 0.4

3.7 16.5 67 0.5

3.1 16.9 67.8 0.4

2.9 17.1 66.6 0.3

1.7 16.2 72.7 0.3

88.6

84.0

85.4

84.0

89.4

a

Source: Nyanzi, S.A., Carstensen, B., Schwack, W., 2005. A comparative study of fatty acid profiles of Passiflora seed oils from Uganda. J. Am. Oil Chem. Soc. 82, 41
44. b Source: Barrales, F.M., Rezende, C.A., Martı´nez, J., 2015. Supercritical CO2 extraction of passion fruit (Passiflora edulis sp.) seed oil assisted by ultrasound. J. Supercrit. Fluids 104, 183
192. c Source: Pereira, M.G., Maciel, G.M., Haminiuk, C.W.I., Bach, F., Hamerski, F., de Paula Scheer, A., et al., 2018. Effect of extraction process on composition, antioxidant and antibacterial activity of oil from yellow passion fruit (Passiflora edulis var. flavicarpa) seeds. Waste Biomass Valoriz. doi:10.1007/s12649-018-0269-y. d Source: Liu, S., Yang, F., Zhang, C., Ji, H., Hong, P., Deng, C., 2009. Optimization of process parameters for supercritical carbon dioxide extraction of Passiflora seed oil by response surface methodology. J. Supercrit. Fluids 48, 9
14.

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machine. Mattos de Paula et al. (2015) also reported that the pressing efficiency using a small-scale machine was around 84% 2 93%. Using a hydraulic press with 16 tonnes of force for 100 min to extract oil from dried, ground seed (20 mesh, moisture content 5.16% w.b.) gave only 9.8% yield (Lea˜o et al., 2014). The obtained crude oil is normally purified only by filtering before bottling.

9.6.2.5 Conventional solvent extraction It is very interesting that solvent extraction of passion fruit oil has been recently reported by a number of authors. Extraction of the oil using hexane, which is a very common solvent for oil extraction, can be achieved. However, because of some concerns relating to health with the use of hexane, other green solvents have been widely studied. Alternative solvents including acetone, ethanol, and isopropanol were tested with different extraction processes including ultrasound-assisted, shaking, and Soxhlet extractions (de Oliveira et al., 2013). Soxhlet extraction with hexane still gave the highest yield of 26.4% while the alternative solvent might be acetone which was more effective when used with the ultrasound-assisted or shaking process. Ultrasonic waves usually help to break the cell structure and therefore enhance extraction efficiency.

9.6.2.6 Super- and subcritical fluid extraction Supercritical carbon dioxide extraction employs carbon dioxide under pressure and at a temperature above its critical point (7.39 MPa and 31 C, respectively) and can give a solvent-free product. The technology is well-established and an industrial-scale instrument for extraction of mainly essential oil is available. The technique was also studied for the extraction of passion fruit seed oil. Extraction with supercritical carbon dioxide at 56 C and 26 MPa for 4 h gave an oil yield of 25.83% from Tainung No. 1 variety (Liu et al., 2009) which was comparable with Soxhlet extraction. The authors also suggested that the quality of oil was suitable for direct use as edible oil. Oliveira et al. (2017) used the supercritical carbon dioxide at 40 C and 15 MPa, with a constant flow rate of 0.5 kg CO2/h for 2.5 to give an oil yield of 21.4% from an initial oil content of 27%. Ultrasonic waves can also be used to enhance the efficiency of supercritical carbon dioxide extraction (Barrales et al., 2015). The extraction system comprised an extraction unit with an ultrasonic probe (20 kHz) connected. The authors indicated that applying 160 W of ultrasound power improved the extraction yield by about 29% at 40 C and 16 MPa. As a related process, the encapsulation of passion fruit seed oil has been done using the supercritical antisolvent method using poly-DL-lactide-co-glycolide (PLGA) as a carrier (Oliveira et al., 2017). Subcritical fluid extraction, on the other hand, usually employs liquid solvents at a temperature higher than their normal boiling point but under their critical temperatures under a pressurized condition. Subcritical propane has been studied for the extraction of various oils from plant sources because of the high solubility of oil compared to supercritical carbon dioxide. Propane is relatively low-cost and easily removed without a toxic residue with a critical point at 97 C and 4.25 MPa. Subcritical propane extraction was tested for the extraction of seed oil from sweet passion fruit (P. alata Curtis) (Pereira et al., 2017) and yellow passion fruit (P. edulis var. flavicarpa) (Pereira et al., 2018). The comparison of subcritical propane extraction, Soxhlet extraction using hexane and ethanol, and ultrasoundassisted extraction with ethanol for the extraction of oil from yellow passion fruit seeds showed that Soxhlet extraction using hexane gave the highest oil yield of 26.12% followed by subcritical propane at 30 C and 8 MPa (24.68%) (Pereira et al., 2018).

9.6.2.7 Fractionation of lipid To add more value and increase certain functional properties of the lipid, fractionation or concentration of some components can be performed. Usually, an unsaponifiable fraction of lipid contains various components with bioactive properties. Laboratoires Expanscience, a French pharmaceutical company, patented the use of a lipid extract rich in an unsaponifiable fraction, which contains mainly tocopherols, tocotrienols, sterols, and squalene, at high concentrations above 3% for dermatological, pharmaceutical, and food applications. The suggested process for concentrating the unsaponifiable fraction is a molecular distillation method (Leclere-Bienfait et al., 2016). In an example from the patent, the lipid after concentration contains total unsaponifiable content of 4.7 g/100 g, in which 2.13 g/100 g is sterol, 0.87 g/100 g is squalene, 0.57 g/100 g is tocotrienol, and 0.09 g/100 g is tocopherol. The company is currently commercializing the product as a cosmetic ingredient under the trade name of PASSIOLINE and it has been incorporated into various brands of cosmetic products.

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9.6.2.8 Miscellaneous applications Cold-pressed oil contains aroma compounds similar to the fruit pulp and therefore the oil can be used for producing liquid soap, shampoo, and cleaning products, etc. to give fresh, citric, and fruity notes. Ethyl butanoate, ethyl hexanoate, and hexyl acetate were the major compounds found in the oil (Lea˜o et al., 2014). In addition, passion fruit seed oil was also investigated for use as a hydraulic biolubricant (Silva et al., 2015). The natural oil could give good lubricity performance but the oil modified by epoxidation gave the best tribological properties, as determined by a high-frequency reciprocating rig equipment.

9.6.3

Piceatannol and scirpusin B

9.6.3.1 Biological activity Piceatannol (3,4,30 ,50 -trans-tetrahydroxystilbene) (Fig. 9.5) is a phenolic compound belonging to a group called stilbenoids, which are abundantly found in several berries. Stilbenoid refers to a phenolic compound with a structure of a hydroxylated derivative of stilbene. Piceatannol and other stilbenoids, including a well-known resveratrol (3,40 ,5trans-trihydroxystilbene), were studied for several biological activities including antioxidation, antiinflammation, anticarcinogenesis, and antiobesity (Chou et al., 2018; Piotrowska et al., 2012). These compounds have gained interest from researchers particularly due to their abundance in grape skin and red wine. Apart from grape, piceatannol can also be found in other plant sources including passion fruit seed but not in the pulp or rind. The content of piceatannol in P. edulis seed was determined by extraction with 70% acetone to be 2.2 mg/g of seed, which is claimed to be very high compared to other sources (Matsui et al., 2010). Piceatannol was extensively investigated for cancer treatment. The compound showed several effects such as immunosuppressive, antileukemic, and antitumorigenic activities in many types of cell lines and animal models (Seyed et al., 2016). Morinaga & Company, Ltd., a Japanese company, had already commercialized passion fruit seed extract as a health care ingredient. The company published several experimental results on the bioactivities of piceatannol and its dimer, scirpusin B (Fig. 9.5), from passion fruit seed extracts (Maruki-Uchida et al., 2013; Kitada et al., 2017; Matsui et al., 2010; Sano et al., 2011). Matsui et al. (2010) compared the ethanolic extracts of rind, pulp, and seed on melanin inhibition and collagen synthesis using cultivated human melanoma and dermal fibroblast cells and found that only the seed extract which contained a high concentration of piceatannol could inhibit melanogenesis and promote the production of collagen in fibroblast cells. A clinical study on Japanese woman revealed that the intake of a passion fruit extract rich in piceatannol helped to increase the moisture content of skin (Maruki-Uchida et al., 2018). Another human study (Kitada et al., 2017) showed that ingestion of piceatannol (20 mg/day) for 8 weeks improved insulin sensitivity, blood pressure, and heart rate in overweight men. In addition, Sano et al. (2011) showed that scirpusin B exhibits higher 1,1-diphenyl-2picrylhydrazyl (DPPH) radical scavenging activity and vasorelaxing effect by ex vivo rat thoracic aorta assay.

FIGURE 9.5 Chemical structure of (A) stilbene, (B) piceatannol, and (C) scirpusin B.

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Currently Morinaga & Co. is selling passion fruit seed extract as a dietary supplement tablet and drink by the trade name of Passienol. The product is advertised for its effects on antiaging. The ingredient is also included in the company’s moisturizing cream and facial washing foam.

9.6.3.2 Extraction Preparation of a passion fruit seed extract rich in piceatannol can be achieved by solvent extraction using aqueous ethanol or acetone. It was shown by the patent from Morinaga & Co. that 80% and 70% are the most suitable concentrations for ethanol and acetone, respectively, and they can be used step-wise, that is first extracting with 80% ethanol and then extracting with 70% acetone, to give a total of 343 mg piceatannol/100 g freeze-dried seed. The crude extract contains piceatannol around 2.6%
3.7% of dry solid (Matsui et al., 2013). However, de Santana et al. (2017) reported that extraction using 70% ethanol by stirring at 80 C for 30 min gave piceatannol as high as 3.68 g/100 g seed from P. edulis. Pressurized liquid extraction (PLE) is a technique for enhancing extraction efficiency by employing an organic solvent at a higher temperature and pressure. Under enough pressure the solvents can be kept in a liquid state even at temperatures higher than their normal boiling points. PLE using ethanol and water as solvents was reported for the extraction of piceatannol (Vigano´ et al., 2016). Using 50% ethanol at 70 C under the pressure of 10 MPa gave a piceatannol content of 18.6 mg/g defatted seed bagasse compared with 11.6 mg/g from maceration using 75% ethanol at 70 C, suggesting that extraction at high temperatures enhanced the yield of piceatannol (de Santana et al., 2017). The process for the extraction of scirpusin B is quite similar. Sano and Sugiyama (2014) described the process to obtain scirpusin B using aqueous ethanol and acetone. Shaking extraction using 80% ethanol (two times), followed by 80% acetone extraction (three times) gave scirpusin B 283 mg/100 g of seeds or 2.5% scirpusin B in the extract. Reflux extraction using 90% ethanol at 92 C for 90 min gave a higher scirpusin B content of 363 mg/100 g of seeds or 3.2% scirpusin B in the extract.

9.6.4

Other phenolic compounds and antioxidant activities

Several phenolic compounds apart from the abovementioned piceatannol and scirpusin B of passion fruit seed were also quantified. Many phenolic compounds and antioxidants are also found in the oil fraction as mentioned above. Antioxidant bioactive compounds from seeds of P. edulis Sims extracted using 70% ethanol with the solid/liquid ratio of 1/10 (w/v) at 80 C for 30 min contained TPC of 3.11 g GAE/100 g seed or 549.6 mg GAE/g extract and piceatannol is the major phenolic compound identified by HPLC-DAD (diode-array detector) and LC
MS/MS analysis. Antioxidant activity measurements showed EC50 value of 26.96 μg/mL for DPPH assay, EC50 of 1.26 mg/mL for β-carotene bleaching (BCB) assay, 3.6 μg acid ascorbic equivalent (AAE)/g dry extract for ferric reducing antioxidant power (FRAP) assay, and 6.2 μmol Trolox equivalent (TE)/g dry extract for oxygen radical absorbance capacity assay (de Santana et al., 2017). Lourith and Kanlayavattanakul (2013) extracted the seed of passion fruit cultivated in Thailand with 40% methanol for 30 min and then fractioned by hexane and ethyl acetate and found that TPC content in the ethyl acetate fraction was highest (58.3 g GAE/100 g fraction) with the strongest antioxidant activities measured by DPPH, 2,20 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), and FRAP assays.

9.6.5

Seed protein

Protein is another major component in passion fruit seed which usually found at 8% 2 18% (Table 9.4). Passion fruit seed protein has been evaluated for nutritive values and it has been found that the protein contains valine, isoleucine, leucine, phenylalanine, and tyrosine higher than the values recommended by FAO/WHO, while threonine, lysine, methionine, and cysteine were lower (Liu et al., 2008). It should be noted that the data above came from the direct hydrolysis of a seed sample and then analysis of the amino acid component with an amino acid analyzer. However, an appropriate protein extraction process and other functional properties of the protein have never been reported.

9.6.6

Antifungal protein

It is known that plants produce several compounds including proteins that can inhibit pathogens. 2S albumin storage proteins, which are also known as major food allergens in some plant seeds, have received attention as a new type of antimicrobial protein. Antifungal activity of 2S albumin protein from passion fruit seed was reported. Agizzio et al.

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(2003) purified two proteins, Pf1 and Pf2 which resemble 2S albumin with molecular weights of 12,088 and 11,930 Da, respectively. These proteins inhibited the growth of fungi Fusarium oxysporum and Colletotrichum lindemuthianum and yeast Saccharomyces cerevisiae and also inhibited acidification of the medium by F. oxysporum. Pelegrini et al. (2006) found another peptide of 5.0 kDa molecular weight, designated as Pe-AFP1, which could inhibit Trichoderma harzianum, F. oxysporum, and Aspergillus fumigatus with IC50 values of 32, 34, and 40 μg/mL, respectively. Passiflin is another antifungal protein isolated and named by Lam and Ng (2009). This 67 kDa dimeric protein was purified in the laboratory and tested for antifungal activity against some plant pathogenic fungi. The N-terminal amino sequence of passiflin was found to resemble bovine β-lactoglobulin, but differs from other antifungal proteins. Passiflin showed inhibition activity against Rhizoctonia solani with an IC50 value of 16 μM, but not Mycosphaerella arachidicola and F. oxysporum when used up to 100 μM.

9.6.7

Seed fiber

Carbohydrate is the largest part of the passion fruit seed. Dietary fiber is usually obtained after a defatting process. Passion fruit seed contains total dietary fiber up to 65 g/100 g dry raw seed or about 86% of defatted seed. About 64 g of the total fiber is insoluble fiber, while only 1 g or less is soluble fiber. From the monosaccharide composition analysis, the fiber primarily contains cellulose, pectic substance, and hemicellulose (Chau and Huang, 2004). The insoluble fiber fraction from passion fruit seed showed a beneficial effect on intestinal health in a study with hamsters and therefore may be employed as a functional ingredient (Chau et al., 2005).

9.7

Conclusion

Passion fruit contains a large proportion that is normally discarded as a by-product. Fortunately, several possibilities for valorization of the by-product have been realized. The peel which is a large part of the by-product can be processed into flour for use as a high-fiber food ingredient, while extraction of pectin from the peel also is very promising. Currently seed oil is receiving much interest from consumers in cosmetics. Innovative products such as highunsaponifiable lipid fraction and seed extracts are also being produced and marketed. It can be expected that more and more value-added products from these by-products will be seen in the food and other industries.

References Agizzio, A.P., Carvalho, A.O., Ribeiro, S.D.F.F., Machado, O.L.T., Alves, E.W., Okorokov, L.A., et al., 2003. A 2S albumin-homologous protein from passion fruit seeds inhibits the fungal growth and acidification of the medium by Fusarium oxysporum. Arch. Biochem. Biophys. 416, 188
195. Almeida, J.M., Lima, V.A., Giloni-Lima, P.C., Knob, A., 2015. Passion fruit peel as novel substrate for enhanced β-glucosidases production by Penicillium verruculosum: potential of the crude extract for biomass hydrolysis. Biomass Bioenergy 72, 216
226. Altendorf, S., 2018. Minor tropical fruits: mainstreaming a niche market. In: FAO (Ed.), Food Outlook. FAO, Rome, Italy. Alves, P.L.D.S., Berrios, J.D.J., Pan, J., Ascheri, J.L.R., 2018. Passion fruit shell flour and rice blends processed into fiber-rich expanded extrudates. CyTA-J. Food 16, 901
908. Barrales, F.M., Rezende, C.A., Martı´nez, J., 2015. Supercritical CO2 extraction of passion fruit (Passiflora edulis sp.) seed oil assisted by ultrasound. J. Supercrit. Fluids 104, 183
192. Bockisch, M., 1998. Fats and Oils Handbook. Academic Press and AOCS Press. Brejnholt, S.M., 2010. Pectin. In: Imeson, A. (Ed.), Food Stabilisers, Thickeners and Gelling Agents. Blackwell Publishing, Oxford. Bussolo de Souza, C., Jonathan, M., Isay Saad, S.M., Schols, H.A., Venema, K., 2018. Characterization and in vitro digestibility of by-products from Brazilian food industry: cassava bagasse, orange bagasse and passion fruit peel. Bioact. Carbohydr. Diet. Fibre 16, 90
99. Canteri, M.H., Scheer, A., Petkowicz, C., Ginies, C., Renard, C., Wosiacki, G., 2010a. Physicochemical composition of the yellow passion fruit pericarp fractions and respective pectic substances. J. Food Nutr. Res. 49, 113
122. Canteri, M.H.G., Scheer, A.P., Wosiacki, G., Ginies, C., Reich, M., Renard, C.M.C.G., 2010b. A comparative study of pectin extracted from passion fruit rind flours. J. Polym. Environ. 18, 593
599. Casarotti, S.N., Borgonovi, T.F., Batista, C.L.F.M., Penna, A.L.B., 2018. Guava, orange and passion fruit by-products: characterization and its impacts on kinetics of acidification and properties of probiotic fermented products. LWT 98, 69
76. CBI, 2018. Exporting Fresh Exotic Tropical Fruit to Europe [Online]. Available from: ,https://www.cbi.eu/market-information/fresh-fruit-vegetables/ exotic-tropical-fruit/europe. (accessed 11.01.19.). Chau, C.F., Huang, Y.L., 2004. Characterization of passion fruit seed fibres—a potential fibre source. Food Chem. 85, 189
194. Chau, C.-F., Huang, Y.-L., Chang, F.-Y., 2005. Effects of fibre derived from passion fruit seed on the activities of ileum mucosal enzymes and colonic bacterial enzymes in hamsters. J. Sci. Food Agric. 85, 2119
2124.

198

Valorization of Fruit Processing By-products

Chemat, F., Rombaut, N., Sicaire, A.-G., Meullemiestre, A., Fabiano-Tixier, A.-S., Abert-Vian, M., 2017. Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review. Ultrason. Sonochem. 34, 540
560. Chou, Y.-C., Ho, C.-T., Pan, M.-H., 2018. Stilbenes: chemistry and molecular mechanisms of anti-obesity. Curr. Pharmacol. Rep. 4, 202
209. Codex Alimentarius Commission, 2017. Standard for named vegetable oils. CODEX-STAN 210-1999, Revised 2017, Food and Agricultural Organization of the United Nations and World Health Organization. Coelho, E.M., Gomes, R.G., Machado, B.A.S., Oliveira, R.S., Lima, M.D.S., de Azeˆvedo, L.C., et al., 2017. Passion fruit peel flour
technological properties and application in food products. Food Hydrocolloids 62, 158
164. Contreras-Esquivel, J.C., Aguilar, C.N., Montanez, J.C., Brandelli, A., Espinoza-Perez, J.D., Renard, C.M.G.C., 2010. Pectin from passion fruit fiber and its modification by pectinmethylesterase. Prevent. Nutr. Food Sci. 15, 57
66. Cordova, F.M., Zibadi, S., Watson, R.R., 2013. Antioxidant and anti-inflammatory actions of passion fruit peel extract in modifying osteoarthritis, hypertension, and asthma. In: Watson, R.R., Preedy, V.R. (Eds.), Bioactive Food as Dietary Interventions for Arthritis and Related Inflammatory Diseases. Academic Press, San Diego. Correˆa, R.C.G., Peralta, R.M., Haminiuk, C.W.I., Maciel, G.M., Bracht, A., Ferreira, I.C.F.R., 2016. The past decade findings related with nutritional composition, bioactive molecules and biotechnological applications of Passiflora spp. (passion fruit). Trends Food Sci. Technol. 58, 79
95. da Silva, A.C., Jorge, N., 2014. Bioactive compounds of the lipid fractions of agro-industrial waste. Food Res. Int. 66, 493
500. de Arau´jo, M.F.M., Veras, V.S., de Freitas, R.W.J.F., de Paula, M.D.L., de Arau´jo, T.M., Uchoˆa, L.R.A., et al., 2017. The effect of flour from the rind of the yellow passion fruit on glycemic control of people with diabetes mellitus type 2: a randomized clinical trial. J. Diabetes Metabol. Disord. 16, 18. de Moura, F.A., Macagnan, F.T., Dos Santos, L.R., Bizzani, M., De Oliveira Petkowicz, C.L., Da Silva, L.P., 2017. Characterization and physicochemical properties of pectins extracted from agroindustrial by-products. J. Food Sci. Technol. 54, 3111
3117. de Oliveira, R.C., de Barros, S.T.D., Gimenes, M.L., 2013. The extraction of passion fruit oil with green solvents. J. Food Eng. 117, 458
463. de Oliveira, C.F., Giordani, D., Lutckemier, R., Gurak, P.D., Cladera-Olivera, F., Ferreira Marczak, L.D., 2016. Extraction of pectin from passionfruit peel assisted by ultrasound. LWT-Food Sci. Technol. 71, 110
115. de Queiroz, M.D.S.R., Janebro, D.I., da Cunha, M.A.L., Medeiros, J.D.S., Sabaa-Srur, A.U., Diniz, M.D.F.F., et al., 2012. Effect of the yellow passion fruit peel flour (Passiflora edulis f. flavicarpa deg.) in insulin sensitivity in type 2 diabetes mellitus patients. Nutr. J. 11, 89. de Santana, F.C., Shinagawa, F.B., Araujo, E.D.S., Costa, A.M., Mancini-Filho, J., 2015. Chemical composition and antioxidant capacity of Brazilian Passiflora seed oils. J. Food Sci. 80, C2647
C2654. de Santana, F.C., de Oliveira Torres, L.R., Shinagawa, F.B., de Oliveira e Silva, A.M., Yoshime, L.T., de Melo, I.L.P., et al., 2017. Optimization of the antioxidant polyphenolic compounds extraction of yellow passion fruit seeds (Passiflora edulis Sims) by response surface methodology. J. Food Sci. Technol. 54, 3552
3561. de Souza, C.G., Rodrigues, T.H., E Silva, L.M., Ribeiro, P.R., de Brito, E.S., 2018. Sequential extraction of flavonoids and pectin from yellow passion fruit rind using pressurized solvent or ultrasound. J. Sci. Food Agric. 98, 1362
1368. do Nascimento, E.M.G.C., Mulet, A., Ascheri, J.L.R., de Carvalho, C.W.P., Ca´rcel, J.A., 2016. Effects of high-intensity ultrasound on drying kinetics and antioxidant properties of passion fruit peel. J. Food Eng. 170, 108
118. Duarte, Y., Chaux, A., Lopez, N., Largo, E., Ramı´rez, C., Nun˜ez, H., et al., 2017. Effects of blanching and hot air drying conditions on the physicochemical and technological properties of yellow passion fruit (Passiflora edulis Var. Flavicarpa) by-products. J. Food Process Eng. 40, e12425. Espı´rito-Santo, A.P., Lagazzo, A., Sousa, A.L.O.P., Perego, P., Converti, A., Oliveira, M.N., 2013. Rheology, spontaneous whey separation, microstructure and sensorial characteristics of probiotic yoghurts enriched with passion fruit fiber. Food Res. Int. 50, 224
231. Espirito-Santo, A.P.D., Mouquet-Rivier, C., Humblot, C., Cazevieille, C., Icard-Vernie`re, C., Soccol, C.R., et al., 2014. Influence of cofermentation by amylolytic Lactobacillus strains and probiotic bacteria on the fermentation process, viscosity and microstructure of gruels made of rice, soy milk and passion fruit fiber. Food Res. Int. 57, 104
113. Fachinello, M.R., Pozza, P.C., Moreira, I., Carvalho, P.L.O., Castilha, L.D., Pasquetti, T.J., et al., 2015. Effect of passion fruit seed meal on growth performance, carcass, and blood characteristics in starter pigs. Trop. Anim. Health Prod. 47, 1397
1403. FAOSTAT, 2018. Crop Statistics. FAOSTAT. Farid, R., Rezaieyazdi, Z., Mirfeizi, Z., Hatef, M.R., Mirheidari, M., Mansouri, H., et al., 2010. Oral intake of purple passion fruit peel extract reduces pain and stiffness and improves physical function in adult patients with knee osteoarthritis. Nutr. Res. 30, 601
606. Foo, L.Y., Lu, Y., Watson, R.R., 2005. Extracts of passion fruit and uses thereof. US Patent No. US7740888B2. United States patent application. Gerbaud, P., 2013. Passion fruit. Fruitrop. Cirad, France. Government of India, 2017. Horticultural Statistics at a Glance 2017. Government of India, New Delhi. Gullon, B., Gomez, B., Martı´nez-Sabajanes, M., Ya´n˜ez, R., Parajo, J.C., Alonso, J.L., 2013. Pectic oligosaccharides: manufacture and functional properties (review). Trends Food Sci. Technol. 30, 153
161. ´ ., Rodrı´guez-Miranda, J., Herman-Lara, E., Torruco-Uco, J.G., Acevedo-Vendrell, O., et al., 2015. Herna´ndez-Santos, B., Vivar-Vera, M.D.L.A Dietary fibre and antioxidant compounds in passion fruit (Passiflora edulis f. flavicarpa) peel and depectinised peel waste. Int. J. Food Sci. Technol. 50, 268
274. Ichimura, T., Yamanaka, A., Ichiba, T., Toyokawa, T., Kamada, Y., Tamamura, T., et al., 2006. Antihypertensive effect of an extract of Passiflora edulis rind in spontaneously hypertensive rats. Biosci. Biotechnol. Biochem. 70, 718
721. Khuwijitjaru, P., 2016. Utilization of plant-based agricultural waste by subcritical water treatment. Jpn. J. Food Eng. 17, 33
39.

Passion fruit Chapter | 9

199

Kidøy, L., Nyga˚rd, A.M., Andersen, Ø.M., Pedersen, A.T., Aksnes, D.W., Kiremire, B.T., 1997. Anthocyanins in fruits of Passiflora edulis and P. suberosa. J. Food Compos. Anal. 10, 49
54. Kitada, M., Ogura, Y., Maruki-Uchida, H., Sai, M., Suzuki, T., Kanasaki, K., et al., 2017. The effect of piceatannol from passion fruit (Passiflora edulis) seeds on metabolic health in humans. Nutrients 9, 1142. Klinchongkon, K., Chanthong, N., Ruchain, K., Khuwijitjaru, P., Adachi, S., 2017a. Effect of ethanol addition on subcritical water extraction of pectic polysaccharides from passion fruit peel. J. Food Process. Preserv. 41, e13138. Klinchongkon, K., Khuwijitjaru, P., Adachi, S., 2017b. Degradation kinetics of passion fruit pectin in subcritical water. Biosci. Biotechnol. Biochem. 81, 712
717. Klinchongkon, K., Khuwijitjaru, P., Wiboonsirikul, J., Adachi, S., 2017c. Extraction of oligosaccharides from passion fruit peel by subcritical water treatment. J. Food Process Eng. 40, e12269. Klinchongkon, K., Khuwijitjaru, P., Adachi, S., Bindereif, B., Karbstein, H.P., van der Schaaf, U.S., 2019. Emulsifying properties of conjugates formed between whey protein isolate and subcritical-water hydrolyzed pectin. Food Hydrocolloids 91, 174
181. Kulkarni, S.G., Vijayanand, P., 2010. Effect of extraction conditions on the quality characteristics of pectin from passion fruit peel (Passiflora edulis f. flavicarpa L.). LWT-Food Sci. Technol. 43, 1026
1031. Lam, S.K., Ng, T.B., 2009. Passiflin, a novel dimeric antifungal protein from seeds of the passion fruit. Phytomedicine 16, 172
180. Lea˜o, K.M.M., Sampaio, K.L., Pagani, A.A.C., Da Silva, M.A.A.P., 2014. Odor potency, aroma profile and volatiles composition of cold pressed oil from industrial passion fruit residues. Ind. Crops Prod. 58, 280
286. Leclere-Bienfait, S., Bredif, S., Debrock, S., Garnier, S., 2016. Lipid extract of passiflora seeds. US Patent No. US20160235794A1. United States patent application. Lewis, B.J., Herrlinger, K.A., Craig, T.A., Mehring-Franklin, C.E., Defreitas, Z., Hinojosa-Laborde, C., 2013. Antihypertensive effect of passion fruit peel extract and its major bioactive components following acute supplementation in spontaneously hypertensive rats. J. Nutr. Biochem. 24, 1359
1366. Liew, S.Q., Chin, N.L., Yusof, Y.A., 2014. Extraction and characterization of pectin from passion fruit peels. Agric. Agric. Sci. Procedia 2, 231
236. Liew, S.Q., Chin, N.L., Yusof, Y.A., Sowndhararajan, K., 2016. Comparison of acidic and enzymatic pectin extraction from passion fruit peels and its gel properties. J. Food Process Eng. 39, 501
511. Liu, S., Yang, F., Li, J., Zhang, C., Ji, H., Hong, P., 2008. Physical and chemical analysis of Passiflora seeds and seed oil from China. Int. J. Food Sci. Nutr. 59, 706
715. Liu, S., Yang, F., Zhang, C., Ji, H., Hong, P., Deng, C., 2009. Optimization of process parameters for supercritical carbon dioxide extraction of Passiflora seed oil by response surface methodology. J. Supercrit. Fluids 48, 9
14. ´ Lvarez, J.A., Viuda-Martos, M., 2013. Chemical, physico-chemical, technological, antibacterial and Lo´pez-Vargas, J.H., Ferna´ndez-Lo´pez, J., Pe´rez-A antioxidant properties of dietary fiber powder obtained from yellow passion fruit (Passiflora edulis var. flavicarpa) co-products. Food Res. Int. 51, 756
763. ´ Lvarez, J.A ´ ., Viuda-Martos, M., 2014. Quality characteristics of pork burger added with albedoLo´pez-Vargas, J.H., Ferna´ndez-Lo´pez, J., Pe´rez-A fiber powder obtained from yellow passion fruit (Passiflora edulis var. flavicarpa) co-products. Meat Sci. 97, 270
276. Lourith, N., Kanlayavattanakul, M., 2013. Antioxidant activities and phenolics of Passiflora edulis seed recovered from juice production residue. J. Oleo Sci. 62, 235
240. Macagnan, F.T., Santos, L.R.D., Roberto, B.S., de Moura, F.A., Bizzani, M., da Silva, L.P., 2015. Biological properties of apple pomace, orange bagasse and passion fruit peel as alternative sources of dietary fibre. Bioact. Carbohydr. Diet. Fibre 6, 1
6. Malacrida, C.R., Jorge, N., 2012. Yellow passion fruit seed oil (Passiflora edulis f. flavicarpa): physical and chemical characteristics. Braz. Arch. Biol. Technol. 55, 127
134. Martinez, R., Torres, P., Meneses, M.A., Figueroa, J.G., Perez-Alvarez, J.A., Viuda-Martos, M., 2012. Chemical, technological and in vitro antioxidant properties of mango, guava, pineapple and passion fruit dietary fibre concentrate. Food Chem. 135, 1520
1526. Martins, M.D., Guimara˜es, M.W., De Lima, V.A., Gaglioti, A.L., Da-Silva, P.R., Kadowaki, M.K., et al., 2018. Valorization of passion fruit peel byproduct: xylanase production and its potential as bleaching agent for kraft pulp. Biocatal. Agric. Biotechnol. 16, 172
180. Maruki-Uchida, H., Kurita, I., Sugiyama, K., Sai, M., Maeda, K., Ito, T., 2013. The protective effects of piceatannol from passion fruit (Passiflora edulis) seeds in UVB-irradiated keratinocytes. Biol. Pharmaceut. Bull. 36, 845
849. Maruki-Uchida, H., Morita, M., Yonei, Y., Sai, M., 2018. Effect of passion fruit seed extract rich in piceatannol on the skin of women: a randomized, placebo-controlled, double-blind trial. J. Nutr. Sci. Vitaminol. 64, 75
80. Matsui, Y., Sugiyama, K., Kamei, M., Takahashi, T., Suzuki, T., Katagata, Y., et al., 2010. Extract of passion fruit (Passiflora edulis) seed containing high amounts of piceatannol inhibits melanogenesis and promotes collagen synthesis. J. Agric. Food Chem. 58, 11112
11118. Matsui, Y., Kamei, M., Sugiyama, K., 2013. Piceatannol-containing composition and method of producing piceatannol-containing composition. US Patent No. US20120004322A1. United States patent application. Mattos De Paula, R.C., Soaresb, A.G., Freitasa, S.P., 2015. Volatile compounds in passion fruit seed oil. Chem. Eng. Trans. 44, 103
108. New Zealand Institute for Plant & Food Research, 2016. Fresh Facts: New Zealand Horticulture. New Zealand Institute for Plant & Food Research. Nyanzi, S.A., Carstensen, B., Schwack, W., 2005. A comparative study of fatty acid profiles of Passiflora seed oils from Uganda. J. Am. Oil Chem. Soc. 82, 41
44. Ocampo, J., Acosta-Baro´n, N., Herna´ndez-Ferna´ndez, J., 2017. Variability and genetic structure of yellow passion fruit (Passiflora edulis f. flavicarpa Degener) in Colombia using microsatellite DNA markers. Agron. Colomb. 35, 135
149.

200

Valorization of Fruit Processing By-products

Occen˜a-Po, L.G., 2006. Banana, mango, and passion fruit. In: Hui, Y.H. (Ed.), Handbook of Fruits and Fruit Processing. Blackwell Publishing, IA, USA, pp. 635
650. Oliveira, C.F., Gurak, P.D., Cladera-Olivera, F., Marczak, L.D.F., 2016. Evaluation of physicochemical, technological and morphological characteristics of powdered yellow passion fruit peel. Int. Food Res. J. 23, 1653
1662. Oliveira, D.A., Mezzomo, N., Gomes, C., Ferreira, S.R.S., 2017. Encapsulation of passion fruit seed oil by means of supercritical antisolvent process. J. Supercrit. Fluids 129, 96
105. Pavan, F.A., Mazzocato, A.C., Gushikem, Y., 2008. Removal of methylene blue dye from aqueous solutions by adsorption using yellow passion fruit peel as adsorbent. Bioresour. Technol. 99, 3162
3165. Pelegrini, P.B., Noronha, E.F., Muniz, M.A.R., Vasconcelos, I.M., Chiarello, M.D., Oliveira, J.T.A., et al., 2006. An antifungal peptide from passion fruit (Passiflora edulis) seeds with similarities to 2S albumin proteins. Biochim. Biophys. Acta 1764, 1141
1146. Pereira, M.G., Hamerski, F., Andrade, E.F., Scheer, A.D.P., Corazza, M.L., 2017. Assessment of subcritical propane, ultrasound-assisted and Soxhlet extraction of oil from sweet passion fruit (Passiflora alata Curtis) seeds. J. Supercrit. Fluids 128, 338
348. Pereira, M.G., Maciel, G.M., Haminiuk, C.W.I., Bach, F., Hamerski, F., de Paula Scheer, A., et al., 2018. Effect of extraction process on composition, antioxidant and antibacterial activity of oil from yellow passion fruit (Passiflora edulis var. Flavicarpa) seeds. Waste Biomass Valoriz. Available from: https://doi.org/10.1007/s12649-018-0269-y. Pinheiro, E.R., Silva, I.M.D.A., Gonzaga, L.V., Amante, E.R., Teofilo, R.F., Ferreira, M.M.C., et al., 2008. Optimization of extraction of high-ester pectin from passion fruit peel (Passiflora edulis flavicarpa) with citric acid by using response surface methodology. Bioresour. Technol. 99, 5561
5566. Piotrowska, H., Kucinska, M., Murias, M., 2012. Biological activity of piceatannol: leaving the shadow of resveratrol. Mutat. Res./Rev. Mutat. Res. 750, 60
82. Roberts, R.E., Mcintosh, H., Delaney, D., 2018. Australian Passionfruit Industry Export Study. Griffith University. Rodriguez-Amaya, D.B., 2012. Passion fruit. In: Siddiq, M. (Ed.), Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging. John Wiley & Sons. Sano, S., Sugiyama, K., 2014. Composition containing scirpusin B, and process for producing composition containing scirpusin B. US Patent No. US20140039049A1. United States patent application. Sano, S., Sugiyama, K., Ito, T., Katano, Y., Ishihata, A., 2011. Identification of the strong vasorelaxing substance scirpusin B, a dimer of piceatannol, from passion fruit (Passiflora edulis) seeds. J. Agric. Food Chem. 59, 6209
6213. Santos, H.H., Rodovalho, R.S., Silva, D.P.D., Morgado, V.N.D.M., 2018. Drying kinetics of passion fruit seeds. Cientı´fica 46, 49
56. Schols, H.A., Voragen, A.G.J., 2002. The chemical structure of pectins. In: Seymour, G.B., Knox, J.P. (Eds.), Pectins and Their Manipulation. Blackwell Publishing, Oxford. Seixas, F.L., Fukuda, D.L., Turbiani, F.R.B., Garcia, P.S., Petkowicz, C.L.D., Jagadevan, S., et al., 2014. Extraction of pectin from passion fruit peel (Passiflora edulis f. flavicarpa) by microwave-induced heating. Food Hydrocolloids 38, 186
192. Seyed, M.A., Jantan, I., Bukhari, S.N.A., Vijayaraghavan, K., 2016. A comprehensive review on the chemotherapeutic potential of piceatannol for cancer treatment, with mechanistic insights. J. Agric. Food Chem. 64, 725
737. Silva, D.C., Freitas, A.L.P., Barros, F.C.N., Lins, K.O.A.L., Alves, A.P.N.N., Alencar, N.M.N., et al., 2012. Polysaccharide isolated from Passiflora edulis: characterization and antitumor properties. Carbohydr. Polym. 87, 139
145. Silva, M.S., Foletto, E.L., Alves, S.M., de Castro Dantas, T.N., Dantas Neto, A.A., 2015. New hydraulic biolubricants based on passion fruit and moringa oils and their epoxy. Ind. Crops Prod. 69, 362
370. Silva, N.C., Duarte, C.R., Barrozo, M.A., 2017. Effects of dehydration methods on quality characteristics of yellow passion fruit co-products. J. Sci. Food Agric. 97, 4750
4759. Thai Department of Agricultural Extension, 2017. Available from: www.agriinfo.doae.go.th/year60/plant/rortor/fruit2/passion.pdf (in Thai). Trujillo-Ramı´rez, D., Lobato-Calleros, C., Roma´n-Guerrero, A., Herna´ndez-Rodrı´guez, L., Alvarez-Ramirez, J., Vernon-Carter, E.J., 2018. Complexation with whey protein hydrolysate improves cacao pods husk pectin surface active and emulsifying properties. React. Funct. Polym. 123, 61
69. ´ ., Simal, S., Solanilla-Duque, J.F., Telis-Romero, J., 2016. Modelling of drying kinetics during non-isothermal convective Va´quiro, H., Rodrı´guez, O drying of passion fruit seeds. Jpn. J. Food Eng. 17, 117
121. Vasco-Correa, J., Zapata Zapata, A.D., 2017. Enzymatic extraction of pectin from passion fruit peel (Passiflora edulis f. flavicarpa ) at laboratory and bench scale. LWT-Food Sci. Technol. 80, 280
285. Vigano´, J., Aguiar, A.C., Moraes, D.R., Jara, J.L.P., Eberlin, M.N., Cazarin, C.B.B., et al., 2016. Sequential high pressure extractions applied to recover piceatannol and scirpusin B from passion fruit bagasse. Food Res. Int. 85, 51
58. Viuda-Martos, M., Ruiz-Navajas, Y., Martin-Sanchez, A., Sanchez-Zapata, E., Fernandez-Lopez, J., Sendra, E., et al., 2012. Chemical, physicochemical and functional properties of pomegranate (Punica granatum L.) bagasses powder co-product. J. Food Eng. 110, 220
224. Wang, X., Lu¨, X., 2014. Characterization of pectic polysaccharides extracted from apple pomace by hot-compressed water. Carbohydr. Polym. 102, 174
184. Wang, X., Chen, Q., Lu¨, X., 2014. Pectin extracted from apple pomace and citrus peel by subcritical water. Food Hydrocolloids 38, 129
137. Yapo, B.M., 2009a. Biochemical characteristics and gelling capacity of pectin from yellow passion fruit rind as affected by acid extractant nature. J. Agric. Food Chem. 57, 1572
1578.

Passion fruit Chapter | 9

201

Yapo, B.M., 2009b. Lemon juice improves the extractability and quality characteristics of pectin from yellow passion fruit by-product as compared with commercial citric acid extractant. Bioresour. Technol. 100, 3147
3151. Yapo, B.M., Koffi, K.L., 2006. Yellow passion fruit rind: a potential source of low-methoxyl pectin. J. Agric. Food Chem. 54, 2738
2744. Yapo, B.M., Koffi, K.L., 2008. The polysaccharide composition of yellow passion fruit rind cell wall: chemical and macromolecular features of extracted pectins and hemicellulosic polysaccharides. J. Sci. Food Agric. 88, 2125
2133. Zanetti, L.H., Murakami, A.E., Diaz-Vargas, M., Guerra, A.F.Q.G., Ospina-Rojas, I.C., Matumoto Pintro, P.T., et al., 2016. By-product of passion fruit seed (Passiflora edulis) in the diet of commercial laying hens. Can. J. Anim. Sci. 96, 488
494. Zanetti, L.H., Murakami, A.E., Diaz-Vargas, M., Guerra, A.F.Q.G., Ospina-Rojas, I.C., do Nascimento, G.R., et al., 2017. By-product of passion fruit seed (Passiflora edulis) in the diet of broilers. Can. J. Anim. Sci. 98, 109
118. Zeraik, M.L., Serteyn, D., Deby-Dupont, G., Wauters, J.-N., Tits, M., Yariwake, J.H., et al., 2011. Evaluation of the antioxidant activity of passion fruit (Passiflora edulis and Passiflora alata) extracts on stimulated neutrophils and myeloperoxidase activity assays. Food Chem. 128, 259
265. Zibadi, S., Farid, R., Moriguchi, S., Lu, Y., Foo, L.Y., Tehrani, P.M., et al., 2007. Oral administration of purple passion fruit peel extract attenuates blood pressure in female spontaneously hypertensive rats and humans. Nutr. Res. 27, 408
416.

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Chapter 10

Pineapple Todor Vasiljevic Institute for Sustainable Industries and Liveable Cities, Victoria University, Melbourne, VIC, Australia

Chapter Outline 10.1 Introduction 10.2 Pineapple waste utilization 10.3 Protein utilization from pineapple waste—bromelain enzyme 10.4 Bromelain extraction strategies 10.5 Membrane filtration process for bromelain extraction 10.6 Application of membrane technology in bromelain purification 10.7 Configurational considerations 10.8 Processing parameters considerations

10.1

203 204 204 209 209 213 213 216

10.9 Bromelain purity 10.10 Valorization of carbohydrates 10.10.1 Insoluble fibers—cellulose and hemicellulose 10.11 Soluble fibers—pectin and gums 10.12 Simple sugars—production of organic acids 10.13 Other value-added products obtained from pineapple waste 10.14 Conclusion References Further reading

217 218 218 218 219 219 220 221 225

Introduction

The global volume of food waste has been recently estimated at 1.6 billion tonnes, resulting in 3.3 billion tonnes of CO2 released into the atmosphere per year (FAOSTAT, 2015). The large majority of this waste, about 42%, has been generated by households, 38% due to food processing, 14% comes from food catering/services sector, and 5% from retail/wholesale. Vegetable and fruit production followed by the dairy, poultry, fishery, and winery industries are the main food sectors generating large volumes of waste (Baiano, 2014). These proportions are summarized in Table 10.1. Normally, the waste from the food industry is used as animal feed, sent for composting or base for fertilizers, or mostly brought to landfills. Unfortunately a significant portion is often unscrupulously disposed of since the cost of disposal may be significant due to high transportation cost and limited availability of landfills (Rani and Nand, 2004), which in turn results in environmental issues. Several food waste handling issues require further consideration, such as (Laufenberg et al., 2003): G G G

prevention of environmental pollution; conservation of energy and new materials; and new methods and policies on waste handling.

The conversion of food waste into useful by-products of higher value, or even as raw materials for other industries as well as food or feed/fodder after biological treatment, has appeared to be a potential avenue for turning waste into a profitable material. Based on these points, bioconversions appear as an attractive solution due to the fact that these residual matters can be potentially converted into useful products. Numerous reports have emerged more recently on waste utilization, especially waste obtained from fruits and vegetables, for further industrial processes including fermentation, bioactive components extraction, etc. (Upadhyay et al., 2010).

Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00010-1 © 2020 Elsevier Inc. All rights reserved.

203

204

Valorization of Fruit Processing By-products

TABLE 10.1 Estimate of waste generated in the food industry (Baiano, 2014). Industrial sector

Waste (%)

Production, processing, and preservation of meat and meat products

8

Production and preservation of fish and fish products

0.4

Production and preservation of fruits and vegetables

14.8

Manufacturing of vegetable and animal oils and fats

3.9

Dairy products and ice cream industry

21.3

Production of grain and starch products

12.9

Manufacture of other food products

12.7

Drinks industry

26

Total

100

The waste from the fruit and vegetable industry consists of fruit and vegetable trimmings, peelings, stems, seeds, shells, cereal residues (such as bran), starch, sugar and juice extraction, and off-spec or damaged products (Baiano, 2014). In addition, some other high-value components can be extracted such as proteins, polysaccharides, fibers, flavor compounds, and phytochemical ingredients. These potentially marketable components can be used in various applications, such as pharmaceutical, cosmetic, food, and nonfood areas. The recovery of these high-value components is an elegant way to reuse the waste streams, as well as being economically interesting (Laufenberg et al., 2003). Among all the fruits and vegetables produced for this industry, pineapple is one of the world’s major crops with a high production each year.

10.2

Pineapple waste utilization

Pineapple (Ananas comosus L.) is an edible member of Bromeliaceae family, and one of the important fruits in the world. According to FAO online database, the world pineapple production in 2014 was 24,778,262 tonnes with a yield of 242,281 hectogram per hectare (Hg/ha) and the number is expected to further increase by year (FAOSTAT, 2015). The fruit is consumed fresh or commercially processed into canned fruits, juice, concentrate, and jam. A steady rise in pineapple production, especially canning, has generated a large amount of waste due to selection and the elimination of unwanted parts (Tanaka et al., 1999), in which 75% of the unwanted parts are in the form of pineapple peel, core, and crown end (Fig. 10.1, Roda et al., 2016a,b). In addition, up to 55% of the generated waste is usually created due to poor fruit handling and exposure to adverse temperature conditions during storage and transport (Nunes et al., 2009). Fortunately the pineapple waste contains many reusable, highly valuable substances that require the application of novel scientific and technological extraction methods. The chemical properties of the different pineapple waste parts are summarized in Table 10.2 (Upadhyay et al., 2010). As indicated, many high-value components such as cellulose (insoluble fiber), protein mainly bromelain, pectin (soluble fiber), and simple sugars are available in different parts and forms of the pineapple waste. Hence numerous efforts on waste utilization for further industrial processes in various fields have been performed, some which are summarized in Table 10.3 and one of the approaches is illustrated in Fig. 10.2. Based on this information, the residues from the pineapple industry can be applied in various fields due to the multifunctional nature of these components. Furthermore, the waste has attractive potential for large-scale utilization due to being readily available, practically free, and renewable. In the following sections some aspects of extraction of valuable components will be provided. While the extraction methods may be numerous, only those that may be scaled up to a commercial level will be covered.

10.3

Protein utilization from pineapple waste—bromelain enzyme

Bromelain is a crude extract from pineapple (A. comosus L.) that contains a mixture of different proteases as well as phosphatases, glucosidases, peroxidases, cellulases, glycoproteins, and carbohydrates (Feijoo-Siota and Villa, 2010). Different types of protease in the bromelain mixture are summarized in Table 10.4 (Barrett et al., 2013).

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205

FIGURE 10.1 Generation of waste during canning of pineapple.

TABLE 10.2 Chemical properties of pineapple waste. Parameter

Peela (ensiled)

Peela (fresh)

Peela (dry)

Moisture (%)

72.49

71.07

27.43










Total solid (%)

27.51

29.03

72.57







Volatile solid (%)

87.12

96.12

95.9




4.7

4.7

3.88

4.1

pH Ash (%)

4 12.88

Wholeb

Skinb

Crownb

Pulpb

Wholec

Peeld




87.5

92.2







12.5

7.8













89.4



















0.7

0.6

0.4

0.2

4.05

10.6

As % dry basis Cellulose

9

11.2

Hemicellulose

4.7

7

Pectin

5.1

6.7

19.4

14

29.6

14.3




19.8

6.5

22.4

20.2

23.2

22.1




11.7

7.1



















12

(Continued )

206

Valorization of Fruit Processing By-products

TABLE 10.2 (Continued) Parameter

Peela (ensiled)

Peela (fresh)

Peela (dry)

Wholeb

Skinb

Crownb

Pulpb

Wholec

Peeld

Ether soluble solid

4

6.1

6.7



















Protein

0.91

3.13

3.3

4.4

4.1

4.2

4.6

5.18




Reducing sugar

5

25.8

27.8

6.5










20.93




Nonreducing sugar

1.7

5.7

4.9

5.2
















Total sugar










11.7
















Lignin

9

11

4.7

1.5

4.5

2.3







11.52

a

Rani and Nand (2004). Ban-Koffi and Han (1990). Abdullah and Mat (2008). d Bardiya et al. (1996). b c

TABLE 10.3 Pineapple waste utilization in numerous applications (Nor, 2017). Application

Description

References

Bromelain

A protease enzyme extracted from pineapple. This enzyme has various applications in the pharmaceutical, medical, food, cosmetic, and textile industries

Murachi (1970), Murachi et al. (1964), Takahashi and Murachi (1976), Yamada et al. (1976)

Ethanol production

Pineapple waste is fermented by microorganisms and catalysts to produce ethanol

Nigam (1999, 2000), Tanaka et al. (1999)

Phenolic antioxidants

High phenolic compounds that are useful for health such as myricetin, salicylic acid, tannic acid, trans-cinnamic acid, p-coumaric acid, syringic acid, and ferulic acid have been identified in pineapple waste. These compounds are extracted from the waste by aqueous methods by using solvents such as ethanol and methanol

Larrauri et al. (1997), Upadhyay et al. (2012)

Organic acid

Pineapple waste is fermented to produce organic acids such as citric, lactic, and ferulic acids which can be commercially used in food and nonfood industries

Idris and Suzana (2006), Kumar et al. (2003), Tilay et al. (2008)

Energy and carbon source

Biomethanation of pineapple waste by anaerobic digestion and composting produces methane gas, while stabilizing effluent with a neutral pH and odorless property. Besides, the waste was utilized as a carbon source to produce hydrogen gas from municipal sewage sludge

Bardiya et al. (1996), Wang et al. (2006)

Antidyeing agent

Pineapple waste is used as a low-cost absorbent to remove basic dyes from polluting the wastewater in textile industry

Hameed et al. (2009), Weng et al. (2009)

Fiber

Fiber from pineapple leaves is utilized in the making of course textile, threads, and polymeric composites

Arib et al. (2006), Devi et al. (1998), Tran (2006)

Removal of heavy metal

Pineapple waste is used as an effective bioabsorbent to remove toxic metals like mercury, lead, cadmium, copper, zinc, and nickel from contaminated sewage sludge

Dacera and Babe (2008), Senthilkumaar et al. (2000)

Animal feed

Dried and ensiled pineapple wastes are utilized as feed for ruminants

Sruamisri (2007), Tran (2006)

Of the different proteases available in a bromelain mixture, commercial bromelain is usually produced from the stem part (stem bromelain), although other pineapple parts contain a certain amount of bromelain as well. Ketnawa et al. (2012) reported the bromelain activity and protein content from different pineapple parts of waste such as peel, core, stem, and crown in Nang Lae and Phu Lae cultivars. They found that the extract from each waste part exhibited

Pineapple Chapter | 10

207

FIGURE 10.2 Illustrative application of membrane processing in the valorization of pineapple waste into highly valuable compounds.

TABLE 10.4 Different proteases in bromelain mixture (Barrett et al., 2013). Name

Source

EC number

Molecular weight

Isoelectric point

Stem bromelain

Pineapple stem

EC 3.4.22.32

24.5

9.55

a

25

4.6

a

Fruit bromelain

Pineapple fruit

EC 3.4.22.33

Pinguinain

Pineapple fruit

EC 3.4.22.33

26

6.5

Ananain

Pineapple stem

EC 3.4.22.31

23.5

. 10

Comosain

Pineapple stem

Not available

24.5

. 10

a

Fruit bromelain and pinguinain are classified under the same EC number.

different proteolytic activity and protein content, with the highest value obtained from the crown part, while the extract from the stem had the lowest value in both cultivars. These findings give a promising opportunity to extract such enzymes sustainably from waste sources. Bromelain has been widely used in pharmaceutical and medical, food, detergent, cosmetic, and textile industries. Some of the major industrial applications of bromelain are summarized in Table 10.5, and have been reviewed by Arshad et al. (2014), Bhattacharyya (2008), Novaes et al. (2016), and Pavan et al. (2012). In the food industry, bromelain is mainly used for meat tenderization since this enzyme can effectively hydrolyze meat myofibril proteins, and is commercially marketed as a meat tenderizer under brands such as McCormick and Knorr (Arshad et al., 2014). It is also used to inhibit fruit browning by preventing the oxidation of phenol to quinone (Ramalingam et al., 2012), to enhance protein stability of beer and wine in alcohol production (Benucci et al., 2011), to improve dough relaxation, and to enhance stability and prevent dough shrinkage in the baking industry (Kong et al., 2007). The utilization of bromelain in fish protein hydrolysis has generated fish protein hydrolysate that possesses nutritional functions and

208

Valorization of Fruit Processing By-products

TABLE 10.5 Industrial applications of bromelain (Nor, 2017). Industry

Applications

Food

Meat tenderization Fruit antibrowning agent Alcohol production Dough improver Fish protein hydrolysate production Food supplement Animal food

Pharmaceutical and medical

Antiinflammatory agent Anticancer agent Digestive aid Potential as antibiotics Debridement cream Platelet aggregation inhibitor Arthritis preventer Antidiarrhea

Cosmetic

Wrinkle treatment Dry skin treatment Tooth whitening Reduce postinjection bruising

Textile

As cocoon softener in silk production Improve dyeing properties

Detergent

Detergent formulation

antioxidant characteristics (Tanuja et al., 2012). Furthermore, bromelain application in animal feed can be used for protein degradation in the feed, increasing the protein inversion and availability, and subsequently decreasing the cost of the feed (Arshad et al., 2014; Tomankova and Kopecny, 1995). The therapeutic application of bromelain has been extensively studied, and the antiinflammatory effects of bromelain has been reported since 1960s (Novaes et al., 2016). This is proven by inflammation pain inhibition in rats in a dose-dependent manner, with further reports of postoperative swelling and pain reduction (Bhattacharyya, 2008). Bromelain is an effective anticancer therapeutic agent, as a result of the systemic response to multiple cellular and molecular targets induced by this enzyme; however, the real underlying mechanisms are yet to be fully understood (Novaes et al., 2016). Also this enzyme has the potential to be used as an antibiotic since it can modify the permeability of organs and tissues to different drugs (Bhattacharyya, 2008). It is reported that bromelain can be used as digestive enzyme in intestinal disorders, suggesting its application as a digestive aid (Knill-Jones et al., 1970; Rathnavelu et al., 2016). Moreover bromelain is used in a debridement cream formulation to eliminate burn debris and accelerate the healing process, and can inhibit platelet aggregation especially for the patients affected with heart attack and stroke, reduce arthritis pathogenesis since it has analgesic properties that can influence pain mediators, and prevent diarrhea by interacting with intestinal secretory signaling pathways (Bhattacharyya, 2008; Pavan et al., 2012). In addition to food and medical applications, bromelain is used in the cosmetic industry to treat various skin conditions such as low skin firmness, wrinkles, and dry skin (Ozlen, 1995). It is also used as a stain remover in teeth cleaning/whitening (Chakravarthy and Acharya, 2012). In the textile industry it is used to improve the dyeing properties of protein fibers such as wool and silk (Koh et al., 2006) and assist in the cocoon-softening process in silk production (Singh et al., 2003).

Pineapple Chapter | 10

10.4

209

Bromelain extraction strategies

Due to various applications, commercial bromelain is very expensive, costing up to US$2400/kg (Spir et al., 2015) primarily due to its high production cost. Thus the development of effective concentration and purification techniques by using waste from the pineapple industry is a current concern in this area, with the aim to minimize the number of operations required to obtain the desired enzyme purity. Various purification strategies used for bromelain have been reviewed extensively (Arshad et al., 2014; Bala et al., 2012; Manzoor et al., 2016; Nadzirah et al., 2013). They normally follow the typical protein purification strategies which can be performed with different separation techniques (Table 10.6). These include (1) chromatography, (2) precipitation, (3) aqueous two-phase system (ATPS), (4) reverse micellar system (RMS), (5) membrane filtration, or (6) the integration of any of these techniques (Table 10.6; Arshad et al., 2014). For each purification approach, the method’s efficiency is evaluated in terms of recovery yield and purity increment of the enzyme. In terms of high enzyme purity and selectivity, chromatography appears to be the best option in comparison to other purification techniques (Nadzirah et al., 2013). Nevertheless, most of the bromelain commercial applications do not require high purity and the enzyme is normally produced as crude in high quantity for applications in high-volume productions (Illanes, 2008). At the industrial level the selection of a suitable purification technique should be focused on the feasibility and practicability of its implementation in a large-scale operation. Since the purification cost can reach up to 80% of the total production cost, the development of low-cost and viable upscalable techniques should be considered (Spir et al., 2015). The advantages and disadvantages of each purification technique are listed in Table 10.7 (Arshad et al., 2014). Among all the mentioned purification techniques (Tables 10.6 and 10.7), chromatography is the least suitable for large industrial-scale application due to its small sample loading capacity that requires multiple purification steps, and thus it is only suitable for small-scale bromelain production. The precipitation method can be easily scaled up; however, it requires the use of different chemicals which are not technologically green. Some restrictions of the ATPS method, including limited range of polarities between the coexisting phases, high cost due to employed polymers, and high viscosity, have limited its potential (Vicente et al., 2016). In addition, difficulties associated with recovering the protein of interest from a solvent final mixture in the RMS method present a serious obstacle for full application of this technology. Membrane filtration technology is an attractive option since it can be easily scaled up with high-throughput, and it is a green technology due to no chemical requirement (Girard and Fukumoto, 2000; Hinkova et al., 2002). It involves minimal operation cost compared to other purification techniques, including the liquid
liquid extraction method (Lopes et al., 2012). This technique has been successfully applied in many protein separation areas that require high purity and efficient operation (Lipnizki, 2010; van Reis and Zydney, 2001). Nevertheless, a few issues related to this technology still need to be solved, especially those related to the separation efficiency, filtration rate, and membrane fouling. Current findings in protein separation via membrane filtration can be adapted as an effort to successfully apply this technology for bromelain purification. Besides, the process optimization should be further investigated to maximize the extraction efficiency, minimize oxidation, avoid denaturalization, and increase protein acquisition (Arshad et al., 2014).

10.5

Membrane filtration process for bromelain extraction

In general, membrane filtration is a separation process of a particulate matter in a continuous liquid using semipermeable materials. It is a pressure-driven process, used for size-based separation that can be classified as either MF, UF, nanofiltration (NF), or reverse osmosis (RO), depending on the membrane pore size, as shown in Fig. 10.3. The membrane pore size is determined by the absolute size of the rejected particles (normally in μm). Besides, the membrane pore size can also be classified according to the molecular weight cutoff (MWCO). The MWCO is defined as the lowest solute molecular weight (MW) that can reach 90% membrane retention and is typically expressed in Dalton (Da) unit. For protein separation application, only MF and UF membranes are normally used to separate and purify proteins, including the bromelain enzyme. The membrane filtration process can be performed either by dead-end or cross-flow filtration modes, depending on its application and scale. In a dead-end filtration mode, the feed passes through the membrane perpendicularly while the permeate is released at the other end. Particulate matter is trapped and accumulated on the filter as the filtration yield. This filtration mode is normally used at small laboratory scales which require the separation of macromolecules in a small volume (Cheryan, 1986). For some larger-scale applications cross-flow filtration is used, in which the separation happens when the feed is moving tangentially across the membrane surface.

TABLE 10.6 Purification techniques for bromelain extraction (Arshad et al., 2014). Technique

Description

Approaches

Chromatography

Protein separation occurs when samples migrate through the column at different rates and conditions of solid stationary and mobile phases. This technique consists of two types of separation mechanisms: (1) adsorption, for example, ion exchange, affinity, hydrophobic interaction; (2) nonadsorption (e.g., gel filtration)

G

Protein separation happens in the cell extract with the addition of salts, polar solvents, nonpolar solvents, and organic polymers extracts by varying the temperature or pH. Protein solubility decreases with the increase of precipitating agent concentration, resulting in protein precipitation

Precipitation

Aqueous two-phase system (ATPS)

Reverse micelle system (RMS)

Protein is separated into two immiscible phases after the mixing of polymer and salts or the combination of two incompatible polymers (PEG and dextran) in an aqueous solution. Factors that may influence the distribution of protein samples between these two phases include ionic strength, pH, temperature, molecular weight of the polymer and type of salt

Protein is separated as droplets from an organic solvent by the presence of surfactant (micelle). This happens due to the polar (hydrophilic) and nonpolar (hydrophobic) regions of the micelle, which induce the protein movement into the micelle. This movement is affected by pH, ionic strength of aqueous phase, and surfactant concentration

Recovery (%)

Purity increment (fold)

Reference

Affinity chromatography

94.8




Chen et al. (2008)

G

Immobilized metal affinity membrane

94.6

15.4

Nie et al. (2008)

G

Expanded bed adsorption




13

Silveira et al. (2009)

G

Ion-exchange chromatography

84.5

10

Devakate et al. (2009)

G

Ammonium sulfate precipitation

82.1

2.5

Hebbar et al. (2012)

G

Ammonium sulfate precipitation

69.7

3.0

Devakate et al. (2009)

G

Isoelectric point precipitation




2.2

Silvestre et al. (2012)

G

Ethanol precipitation

98

2.3

Soares et al. (2012)

G

Acetone precipitation

86

4.9

Chaurasiya and Hebbar (2013)

G

Ethanol precipitation




3.1

Silvestre et al. (2012)

G

Polyethylene glycol (PEG)/(K2HPO4/ KH2PO4) aqueous two-phase system (ATPS)

93.1

3.2

Hebbar et al. (2012)

G

PEG/MgSO4 ATPS

108.4
206

2.2
3.44

Ketnawa et al. (2011), Ketnawa et al. (2010), Ketnawa et al. (2009)

G

PEG/K2SO4 ATPS

228

4.0

Babu et al. (2008)

G

Block copolymer ATPS

79.5

1.3

Rabelo et al. (2004)

G

PEG/MgSO4 ATPS

335.3

25.8

Novaes et al. (2013)

G

Cetyltrimethylammonium bromide (CTAB)/isooctane/hexanol/butanol Reverse Micellar System (RMS)

106

5.2

Hebbar et al. (2008)

G

CTAB/isooctane/hexanol/butanol RMS

97.6

4.5

Hemawathi et al. (2007)

G

CTAB/isooctane/hexanol/butanol RMS

78.9

4.0

Chaurasiya and Hebbar (2013)

G

Benzil Dodecyl Bis(hydroxyethyl) Ammonium Chloride (BDBAC)/ isooctane/hexanol RMS




4.9

Fileti et al. (2010)

G

Affinity-based RMS

228

12.3

Kumar et al. (2011)

Membrane filtration

Protein fractionation and concentration are done according to size by using semipermeable membranes. It normally involves several filtration stages, where at the final filtration stage bromelain is retained in the system and further recycled until the desired concentration is achieved

G

Microfiltration (MF) and ultracentrifugation

85
100




Lopes et al. (2009, 2012)

Integrated techniques

Different purification techniques are combined to get high bromelain purity and recovery

G

MF, ammonium sulfate precipitation, ultrafiltration (UF), and ultracentrifugation

50




Doko et al. (1991)

G

Nano-TiO2 absorption and two-stage UF

64.8

5.3

Chao et al. (2009)

G

High-speed countercurrent chromatography and reverse micelle system

95.5

5.6

Yin et al. (2011)

G

Reverse micelle system and UF

94.2

5.7

Yin et al. (2011)

G

Reverse micelle system and UF

95.8

8.9

Hebbar et al. (2012)

212

Valorization of Fruit Processing By-products

TABLE 10.7 Comparison of different purification strategies (Arshad et al., 2014). Type of purification

Advantages

Chromatography

G

Highly specific and scalable

Disadvantages G G G

Precipitation

G G G

Aqueous two-phase system

G G G

Reverse micelle system

G

G G

Membrane filtration

G G

Low separation efficiency and high cost Small sample loading capacity Multiple chromatography steps

Upscalable with simple equipment requirement Low energy needed Effective for removal of trace contaminants

G

Need dialysis step to remove excessive salt during precipitation

Low cost and shorter separation time Upscalable and produces higher yield Effective for removal of trace contaminants

G

Difficult to recover target protein from phase-forming polymer

Upscalable and can be operated in a continuous mode No loss of native protein and activity Low interfacial tension

G

Difficult to recover target protein from surfactant-containing organic solvent

Concentrates the protein Effective for removal of trace contaminants

G

Long separation process Increased protein loading will cause UF membrane clogging

FIGURE 10.3 Different types of membrane separation (Nor, 2017).

G

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213

Application of membrane technology in bromelain purification

Numerous attempts have been focused on membrane-based processes for bromelain production either as a single process or in combination with other purification techniques. A multistage membrane process for the separation and concentration of bromelain from different pineapple parts has been described by Lopes et al. (2009), Gimeno et al. (2010), and Nor et al. (2016), which involved MF and UF. Several studies on the integration of membrane process with other purification technologies have been reported, such as with ammonium sulfate extraction (Doko et al., 1991), RMS (Hebbar et al., 2012), ATPS (Babu, 2008), and nano-TiO2 absorption (Chao et al., 2009). Studies on utilizing membranes for the purification of bromelain are summarized in Table 10.8 (Nor et al., 2017). Despite this promising laboratory work, the potential to implement the outcomes to large-scale bromelain production still needs to be explored. The membrane processing efficiency, particularly associated with the permeate flux and membrane fouling behavior, is strongly related to the composition of the feed. Extracts from plants including pineapple usually contain various components such as polysaccharides (soluble and insoluble fibers), proteins, pigments, and minerals. The composition is influenced by various factors including the type of plant, varietal characteristics, maturity, natural variation, climate, and cultural practices (Girard and Fukumoto, 2000). Very large components in the plant extract typically consist of soluble and insoluble complexes, colloids (mainly polysaccharide complexes), microorganisms, and starch. Proteins, including enzymes, and pectin are the medium-sized entities while small compounds in the plant extract typically include numerous sugars, organic acids, amino acids, phenolic compounds, pigments, essential oils, vitamins, and minerals (Fig. 10.4, Nor et al., 2017). The targeted enzyme can be separated from the other components based on size exclusion. Very large particulates can easily be discarded by using centrifugation and MF process, whereas NF or small MWCO UF can be used to filter the small size components from the targeted enzyme. Nevertheless, the separation of enzyme and protein from the pectin component is complicated and requires a precise separation based on their size. Bromelain enzyme has an MW of c.23.4
35.73 kDa (Arshad et al., 2014) while pectin has MW of 10
500 kDa with a global weight average of about 100 kDa (Girard and Fukumoto, 2000). Pectin is found to be responsible for the fouling build-up during membrane processing by forming high MW aggregates which in turn hinder membrane performance (Nor et al., 2015). It can be perceived as an impediment to the process, although it can also be considered as a valuable product for some types of juice fruit processing. In the case of pineapple it was reported that this fruit contains a small but a noticeable yield of pectin (Mohamed and Hasan, 1995; Normah and Ku Hasnah, 2000). In addition, a high hemicellulose content, including galactomannans, arabinogalactans, and galactoglucomannans, and a natural gum (a neutral polysaccharide containing 70% sugars, which are predominantly galactomannans) are present in pineapple juice which can also cause a quick reduction in the UF flux rate (Grassin and Fauquembergue, 1996). Also 0.06% (w/v) crude pectin was reported in the crude pineapple waste mixture extract (Nor et al., 2015). In order to reduce the potential of larger molecules causing fouling during the membrane processing, pretreatment of the feed should be considered. The treatment may consist of hydrolyzing soluble polysaccharides, which are responsible for the high viscosity of the juice, as well as liquefying the nonsoluble polysaccharides, such as nonsoluble pectins, cellulose, hemicellulose, and lignin from cell walls (Tochi et al., 2009)—this includes the enzymatic treatment of the feed with pectinase and cellulase enzymes.

10.7

Configurational considerations

It is important to select a suitable membrane configuration and features for higher resolution of bromelain separation from the pineapple extract. While the following section discusses the application of membrane processing for bromelain extraction, a multistage system (or systems) may be configured to allow for robust component separation that would be further processed downstream. For this reason a multistage membrane processing with or without the application of other purification techniques appears the most feasible approach. This approach predominantly involves the separation of bromelain from other macromolecules during the initial filtration stage (usually MF) and the concentration of the enzyme in the final filtration stage (mainly UF) (Fig. 10.2; Doko et al., 1991; Lopes et al., 2009; Gimeno et al., 2010). The enzyme can be further purified and concentrated using either RO or direct osmosis (DO) with diafiltration (Babu, 2008) as steps in the preparation of the concentrate for drying. Multistage membrane systems have been successfully used for isolating a protein of interest for various applications. Some of the systems included use of high-performance tangential flow filtration, known as HPTFF and introduced by van Reis et al. (1997), which employed various strategies of exploiting differences in both size and charge to achieve high resolution of protein selectivity. By performing the HPTFF system, particularly in a two-stage UF process using

TABLE 10.8 Summarized investigations on bromelain separation by membrane filtration process (Nor et al., 2017). Approach

Sample

Pretreatment

Membrane details Membrane system

Filter material

Processing conditions Pore size

Surface area (m2)

pH

TMP (bar)



Temp ( C)

Flow rate (mL/min)

Volume reduction factor (VRF)

Two-stage membrane filtration, starting by MF followed by UF

Pineapple pulp extract in phosphate buffer




Two-stage UF system

Pineapple waste extract




12.5 ppm antifoaming agent and 200 ppm hemicellulase

Purification

Enzyme

fold (by membrane

yield (%)

References

process itself)

MF—flat sheet

Polyvinyl fluorite

0.1 μm

0.0225

7.0 and 7.5

0.05
0.15

Room temp.










85

UF—centrifugal filter




10 kDa




7.0 and 7.5




4




10




100

UF stage 1—tubular

Ceramic (zirconium oxide)

75 kDa

0.0055

4, 5, 5, 7 and 8.5

2

10
40

6900

15




96.8

UF stage 2—tubular

Ceramic (zirconium oxide)

10 kDa

0.0055

4, 5, 5, 7 and 8.5

2

10
40

69

15

2.5




MF—tubular

Ceramic (zirconium oxide)

8 μm

0.2

8.5




30 6 2













UF—tubular

Polysulfone

10 kDa

0.46

8.5

3

30 6 2




7.4
17.1




97

Lopes et al. (2009, 2012)

Nor et al. (2016)

Purification by multiple processing steps involving MF, UF, ammonium sulfate extraction, ultracentrifugation, and freeze drying

Pineapple fruit extract

Integration of the purification technique by coupling reverse micellar extraction (RME) process with UF

Pineapple core extract in sodium phosphate buffer




Tangential flow filteration (TFF)

Celluose acetate

5 kDa

0.005




1

25 6 2

3

5

1.5

92.4

Hebbar et al. (2012)

Three-stage membrane filtration involving 2 MF processes and an UF

Pineapple waste (peel and core)




MF




1.2 and 0.2 μm

























Gimeno et al. (2010)

UF—centrifugal filter

Regenerated cellulose

10 kDa

0.00076






















Purification and concentration process involving the aqueous two-phase system (ATPS), UF and direct osmosis (DO)

Pineapple core and peel extract in sodium phosphate buffer




UF—flat sheet

Polysulfone

10 kDa

0.0016

7

1
4

25 6 2







2 1.2




DO—flat sheet

Hydrophilic direct osmosis




0.012







25 6 2

100










Integration of the purification process by coupling nano-TiO2 absorption with twostage UF

Pineapple stem extract










50 and 10 kDa







2.5
3










1.4

64.7

Doko et al. (1991)

Babu (2008)

Chao et al. (2009)

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FIGURE 10.4 Typical composition of plant extracts and corresponding MWs (Nor et al., 2017).

FIGURE 10.5 A two-stage UF closed-loop cascade system for bromelain extraction (Nor et al., 2016).

membrane filters with MWCO of 150 and 10 kDa, they managed to separate bovine serum albumin (BSA) monomer from oligomers with purification factor of 9 and 86% yield. The two-stage UF strategy comprises two UF membrane filters with the pore size larger (stage 1) and smaller (stage 2) than the targeted protein of interest. The application of the two-stage UF strategy has also been reported for different types of proteins, such as the separation of α-lactalbumin and β-lactoglobulin from whey protein isolate (Cheang and Zydney, 2004), ovalbumin (OVA) from chicken egg white (Datta et al., 2009), and surfactin from fermentation broth (Isa et al., 2007), and can potentially be used for bromelain separation. For example, Nor et al. (2016) reported an increment of 2.5-fold purity of bromelain by applying the twostage UF system which consisted of membranes with MWCO bigger (in the UF stage 1) and smaller (in the UF stage 2)

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Valorization of Fruit Processing By-products

than the bromelain MW. Since bromelain has an MW ranging from 23.4 to 35.73 kDa (Arshad et al., 2014), for the two-stage UF application, the MWCO of the first stage membrane filter should be at least two times higher (75 kDa) and the second stage membrane filter two times lower (10 kDa) than that range (Nor et al., 2016) (Fig. 10.5). The choice of membrane material in membrane processing is dependent on the processing pressure, temperature, and pH tolerance and chemical compatibility (Girard and Fukumoto, 2000). The membrane process for bromelain purification requires mild processing condition, usually between 0.5 and 4 bar, 10 C
30 C, pH 4 to 8.5 with no corrosive compounds or chemicals involved, which is suitable for many membrane materials. However, the cleaning procedure for the membrane is normally performed under more aggressive conditions with the application of strong acids or alkaline detergents at a higher temperature (60 C
80 C), which should be taken into consideration during membrane selection. Most of the previous studies have used polymeric membranes, such as polysulfone, polyvinyl fluorite, and cellulose acetate, with the exception of Doko et al. (1991) and Nor et al. (2016) who used ceramic membranes (zirconium oxide). Ceramic membranes are classically more durable than the polymeric membranes. Examples of ceramic membranes include alumina (α-Al2O3 and β-Al2O3), zirconia (ZrO2), titania (TiO2), glass (SiO2), and silicon carbide (SiC) (Lee et al., 2015). They exhibit far superior mechanical, thermal, and chemical resistivity allowing much more extreme cleaning approaches without the risk of damaging the membranes (Lee et al., 2013). Furthermore, ceramic membranes have been reported to have a relatively narrow pore size distribution and higher porosity (Lee et al., 2002; Hofs et al., 2011), which are suitable for bromelain purification since better protein separation can be achieved using a membrane with a smaller pore size distribution (van Reis et al., 1997). Moreover, ceramic membranes exhibit lower organic fouling tendencies in certain circumstances compared with the polymeric membranes due to their hydrophilic and inorganic characters (Lee and Kim, 2014).

10.8

Processing parameters considerations

The feasibility of any membrane process can be affected by several processing parameters, including feed pH and concentration, transmembrane pressure (TMP), temperature, flow rate, and cross-flow velocity. Table 10.9 includes different processing parameters reported by various studies for the membrane process of bromelain. The feed pH appears to be one of the main processing factors (Lopes et al., 2009) as it influences the bromelain activity recovery by MF. The best recovery of activity appears to be obtained at pH 7.0 (Lopes et al., 2009). The same feed pH has been selected by Babu (2008) while Doko et al. (1991) chose to adjust the feed pH to 8.5 in their membrane-based process. To explore the role of pH more closely, Nor et al. (2016) investigated the effect of adjusting the feed pH on the flux behavior, enzyme recovery, and enzyme purity during the bromelain purification process. The pineapple extract used in their study was labeled as the crude waste mixture (CWM), which consisted of a specific ratio of different parts of pineapple waste including crown, peel, and core. The CWM extract was adjusted to four pH levels of 4, 5.5, 7, and 8.5. Improved flux behavior was achieved at feed pH 7, which might be strongly related to the viscosity reduction of the feed after the pH was changed away from its isoelectric point (pI) and thus improved the filtration rate in the membrane process. This is in agreement with their previous study (Nor et al., 2015), where observations on the effect of the CWM extract rheological properties at different pH also found a viscosity reduction when the pH was adjusted above its pI, since it leads to greater repulsion between the macromolecules. The TMP is also a primary processing parameter which effectively increases the filtration rate. In general, higher TMP leads to a higher filtration rate, particularly in the membrane pressure-dependent region. However, the flux TABLE 10.9 Recommended improvements for membrane processing of bromelain separation (Nor et al., 2017). Considerations

Recommended improvements

Various components in the feed

G

Conducting enzyme pretreatment to minimize impact of other macromolecules during the membrane process

Efficiency of the process and purity of bromelain

G

Implementing the HPTFF strategy particularly using the two-stage UF system, which consists of membranes with MWCO two times bigger and smaller than the molecular weight of bromelain Use of more robust membranes, that is, ceramic membranes Adopting other membrane processing approaches including diafiltration, gas sparging, etc. Optimizing relevant processing conditions including TMP, cross-flow velocity, pH, and temperature

G G G

Economy evaluation

G

Establishing capital and investment cost. Operational cost should be further appraised based on the recommendations given above

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becomes independent of pressure due to the concentration polarization layer reaching its limiting concentration as the pressure increases further (Cheryan, 1986). Although high TMP would lead to a high filtration rate, the impact on enzyme activity should be considered (Lopes et al., 2009). The enzyme inactivation may take place due to conformational changes while passing through the membrane pores or due to contact with the fouling material. Table 10.8 shows the effects of high cross-flow rate and velocity parameters on bromelain separation. Flux normally increases with an improvement in hydrodynamic conditions on the surface of the membrane due to the high shear rates generated on the surface of the membrane, since these higher rates shear off more deposited material and consequently reduce the hydraulic resistance of the fouling layer (Cheryan, 1986). Selectivity of the membrane has been enhanced by increasing the cross-flow rate, since soluble protein and peptide transmission is promoted. For example, Datta et al. (2009) studied the effects of stirring speed on the separation of OVA from chicken egg white using a two-stage UF 50 and 30 kDa stirred cell. In both UF stages, the permeate flux was found to increase with the enhanced rate of stirring because of the enhanced turbulence at the membrane surface, resulting in a reduction of concentration polarization. Based on the data in Table 10.8, most of the studies have performed bromelain separation by membrane filtration at room temperature (B25 C
30 C). Increasing the processing temperatures may improve the permeation rate since at higher temperature, the membrane permeability coefficient and the diffusivity coefficient are higher, and the viscosity coefficient decreases (Girard and Fukumoto, 2000). This has been proven by Nor et al. (2016) who observed the effect of different processing temperatures, ranging from 10 C to 40 C, on the flux during the separation of bromelain by UF. The best flux was obtained at 40 C indicating the need to operate the process at the highest possible temperature for the maximum flux. However, the stability of the enzyme during the operation also needs to be considered since high temperature may lead to the denaturation of the protein and the reduction of bromelain activity as well as potential fouling issues due to particle
particle interactions (Nor et al., 2015). Bromelain activity has been found to decline by 17% when the process was operated at 50 C for 60 min (Jutamongkon and Charoenrein, 2010), nevertheless the enzyme remained relatively stable at least for 1 week at room temperature (Hale et al., 2005). Furthermore, an increase of 3%
4% on the average processing capacity has been reported for every 1 C increase in operating temperature between 20 C and 60 C (Girard and Fukumoto, 2000), signifying the importance of ensuring the optimum balance between the membrane filtration rate, enzyme stability, and operating costs.

10.9

Bromelain purity

The purity of the separated bromelain after the membrane process is the main consideration in evaluating the performance of the membrane filtration. In general, purification of 1.2- to 2.5-fold have been reported (Table 10.8) by using the membrane process itself and the purity can be further improved by increasing the volume reduction factor (VRF) of the process (Nor et al., 2016). Besides increasing the VRF, it is believed that the bromelain purity can be further increased by implementing different filtration strategies such as using the HPTFF method as discussed in the previous section. By using this method, van Reis et al. (1999) reported 900-fold purification with a 90% yield when separating BSA from an antigen-binding fragment of monoclonal antibody (Fab). A similar work except using a complex multicomponent feed stream, that is, whey protein isolate, has demonstrated greater than 10-fold purification with 90% yield for the recovery of α-lactalbumin (Cheang and Zydney, 2004). Moreover, for higher grade enzyme purity, the combination of the membrane technology with other purification methods can be considered. Performing the UF process after RMS in an integration purification process has resulted an increase of bromelain purity from 5.9-fold to 8.9-fold after the process (Hebbar et al., 2012). Purification of 1.5-fold can be achieved during the UF process itself after 5-fold volume reduction. In other studies the application of the membrane process with a combination of other purification methods has been found to exhibit varying levels of bromelain purity including an increase of 2.0 to 2.8-fold with the combination of ammonium sulfate extraction (Doko et al., 1991) and 5.29-fold when coupled with the nano-TiO2 absorption process (Chao et al., 2009). Nevertheless, most of the commercial applications of bromelain do not require a high purity of the enzyme except for the medical, pharmaceutical, and research areas. The enzyme is normally produced using less complex processes in high volumes for use in bulk production of food, feed, and fabrics (Illanes, 2008). Hence the bromelain purification process can be intuitively designed depending on the destination of the enzyme (Costa et al., 2014). The purification process can be employed to purify the protein of interest to the extent required for its final purpose (Jervis and Pierpoint, 1989). An increment of 2- to 4-fold purity has been recommended by Nor et al. (2015) for bromelain applications in the food industry, and this is achievable by using membrane filtration processes. Economic consideration in the application of membrane-based processing for bromelain purification is crucial for the feasibility of the production. Lopes et al. (2012) provided an economic evaluation of bromelain production by

218

Valorization of Fruit Processing By-products

membrane processing. They analyzed the related bromelain production cost per hour and per day in Sao Paulo, Brazil, with the stipulation of the concentrated enzyme value of 125 mL/h and 1 L/day. The cost calculation included the cost of reagent, raw material, services, water, sewage, and energy involved, but the indirect costs, general materials, insurance, and depreciation were not taken into consideration. An estimated cost of US$12.68 to 16.03 per hour and US $99.27 to 128.23 per day has been reported to be 9
13 times lower than the same highly purified enzyme offered by pharmaceutical companies. In addition, the cost estimated in this study was 6.5
8.5 times less than the previous report of the economic analysis of bromelain production using liquid
liquid extraction technology. However, it is necessary to emphasize that the sale price of bromelain is not solely dependent on the production cost and might be influenced by other factors, such as the indirect overhead costs, demands, marketability of the product, etc., which may lead to a higher market price. Overall the membrane technology presents a potential and attractive purification method for commercial bromelain production. Several recommendations for improvement have been discussed by adapting the successful studies on protein separation, and these are summarized in Table 10.9.

10.10 10.10.1

Valorization of carbohydrates Insoluble fibers—cellulose and hemicellulose

As indicated in previous sections, pineapple waste contains very high amounts of cellulose and hemicellulose, which makes it a suitable candidate for the production of cellulose derivatives and composites with applications in food and polymer industries. The cellulose from pineapple peels may be derivatized into carboxymethyl cellulose and used in the preparation of environment-friendly packaging material (Chumee and Khemmakama, 2014). Cellulose composites or nanocellulose on the other hand have showed some promising applications in the biomedical field, due to their biocompatibility, low cytotoxicity, and biodegradability (Jorfi and Foster, 2015). The main characteristic of nanofibers is their large surface area, which allows the enhanced cell adhesion of proteins and pharmacological molecules while facilitating controlled drug-release (Leung and Ko, 2011). One of the major problems for the commercial application of these derived compounds resides in the complexity and feasibility of the extraction processes. For example, to prepare carboxymethyl cellulose, Chumee and Khemmakama (2014) obtained pure cellulose by refluxing pineapple peel powder with 0.5 M HCl and 1 M NaOH solution at 90 C for 1 and 2 h, respectively, followed by bleaching with calcium hypochlorite. The optimum condition for carboxymethylation was cellulose 5 g, chloroacetic acid 13.0 g, and 40% (w/v) NaOH 50 mL. Similarly, cellulose nanofibers are prepared after extraction to remove pectins and some hemicellulose by heating with 2% sodium hydroxide solution at 100 C for 4 h (Santos et al., 2013). After drying the dry extract is bleached with a solution made of equal parts acetate buffer and aqueous sodium chlorite at 80 C for 4 h. The bleached material is washed to achieve a neutral pH and then dried at 50 C for 12 h and milled. The powder is then acid hydrolyzed using sulfuric acid, centrifuged, and the precipitate is dialyzed for 4 days to obtain cellulose nanocrystals. These nanocrystals are needle-shaped, thermally stable, and highly crystalline with an average length of 249.7 nm and a diameter of 4.45 nm (Santos et al., 2013). Detailed methods for the extraction of cellulose nanofibers from various biomass materials have been extensively reviewed by Menon et al. (2017). Cellulose nanofibers are traditionally obtained by acid hydrolysis by partially dissolving cellulose fibrils (Feng et al., 2015). Naturally cellulose microfibrils are biosynthesized and self-assembled by repeatedly aggregating along cellulose chains creating crystalline and amorphous domains (Haafiz et al., 2014). These amorphous regions are preferentially hydrolyzed and removed when subjected to strong acid hydrolysis, while the crystalline regions are more acid resistant (Feng et al., 2015). Sulfuric acid is the most common hydrolyzing agent as it readily reacts with hydroxyl groups on the surface of cellulose through esterification. The process yields anionic sulfate ester groups which leads to the dispersion of the nanofibers in water by electrostatic repulsion due to enhanced electronegativity (Dufresne, 2013; Feng et al., 2015).

10.11

Soluble fibers—pectin and gums

Pectin presents a heterogeneous group of anionic structural polysaccharides found in fruit and vegetables and pectin is mainly prepared from waste citrus peel and apple pomace. It has a complex structure consisting of units of galacturonic acid as the main chain (Mohamadzadeh et al., 2010). α-L-Rhamnose units are occasionally inserted and the carboxyl groups are partially esterified by methyl alcohol. The extraction of pectin involves multiple steps, during which hydrolysis and extraction take place, and it is governed by a multitude of factors including temperature, pH, type of acid (inorganic or organic), and presence of chelating agents (EDTA, ammonium oxalate, or sodium hexametaphosphate)

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219

(Kliemann et al., 2009). This type of pectin contains more than 50% of the carboxylic acid groups esterified, which makes it a high methyl ester pectin according to its gelling temperature. Modifying the extraction process or applying an acid treatment yields a low methyl ester pectin with less than 50% methyl ester groups. The pectin structure governs its application, and thus high methoxyl pectin gel is created via the formation of hydrogen bonds and hydrophobic interactions in the presence of acid (pH 3.0), which reduces electrostatic repulsions, and sugars, which modulate polymer
water interactions. Low methoxyl pectin on the other hand in the absence of particular cations would gel through cooperative associations at low temperatures (Constenla and Lozano, 2003). As the ability of pectin to form gel depends on the molecular size and degree of esterification, pectin from different sources does not have the same gelling ability. Therefore the industry is constant looking to identify new sources of this polysaccharide and establish its physicochemical properties. Pineapple appears as a less suitable candidate for pectin extraction due to the fairly low concentration (approximately 15% of the total dietary fiber), and thus its extraction would be hindered by other major polysaccharides. Only a few reports are available in literature and all of them used some form of acid extraction due to the high yields achieved (Boobrad et al., 2006). In general the extraction process may involve use of highly concentrated organic or inorganic acids that usually solubilize pectin during heating at elevated temperatures for a certain period of time (Boobrad et al., 2006). Following solubilization pectin is precipitated either by ethanol or salt precipitation. Considering the conditions of extractions, any process design to extract pectin from pineapple waste needs to be deemed feasible. In many instances, such as the extraction of bromelain, pectin is rather considered a hindrance and additional steps may need to be incorporated into the process to allow for more efficient separation of bromelain from the remaining solids (Nor et al., 2017). Alternatively pineapple waste, in special reference to soluble fiber, could be used as a prebiotic. Prebiotics define a large group of food ingredients that are not digestible by human enzymes and thus transition into the gut where they are fermented by probiotics. Probiotic bacteria, mainly composed of bacterial genera of Bifidobacteria and Lactobacilli, once established in the human intestine have a beneficial effect on host health. Diaz-Vela et al. (2013) showed that dried pineapple peel waste had a positive effect on the growth of Pediococcus pentosaceus UAM22, Aerococcus viridans UAM21, and Lactobacillus rhamnosus GG indicating that the fibers were metabolized selectively by probiotics microorganisms. Similarly heat-treated pineapple biomass served as a promising prebiotic supplement in dairy and functional products, promoting the growth of probiotic microbiota and consequently the release of antimutagenic and antioxidant peptides (Sah et al., 2015).

10.12

Simple sugars—production of organic acids

Pineapple is rich in simple sugars mainly fructose, and thus the waste contains considerable amounts of fermentable sugars. Fermentation is typically used to convert these free sugars into different organic acids. The production of lactic, citric, succinic, and acetic acids from pineapple waste has been reported (Banerjee et al., 2017). Lactic acid is among the most important organic acids due to various applications in both food and biopolymer industries. Lactic acid was produced from pineapple syrup using a strain of Lactobacillus lactis (Ueno et al., 2003). On the other hand, Idris and Suzana (2006) used an immobilized strain of Lactobacillus bulgaricus, while fungal strains have also been used (Jin et al., 2005). The strains included Rhizopus arrhizus and Rhizopus oryzae, respectively. Citric acid is used as an acidulant to enhance the flavor of the products. It can be produced by solid-state fermentation of pineapple waste using Aspergillus niger (Kumar et al., 2003). The yield of citric acid can be improved with addition of Yarrowia lipolytica as the fermentation aid (Imandi et al., 2008). Succinic acid is another organic acid that is used as an acidity regulator. It also acts as a flavoring agent which adds sourness or astringency to the food. Pineapple waste serves as a suitable substrate for the production of succinic acid (Jusoha et al., 2014), yielding similar quantities of succinic acid to that obtained by the fermentation of glucose. Succinic acid can be derivatized into fumaric acid and dimethyl fumarate with various applications in the food and pharmaceutical industries. Acetic acid, or its more diluted commercial form, vinegar, can be produced from pineapple peel using a two-stage fermentation process (Sossou et al., 2009). Water is added to pineapple peel, heated, and then pressed to obtain juice which is then concentrated to 20% soluble solids and used for vinegar production through alcoholic and acetic fermentations. Acetic fermentation is carried out at 30 C using an acetic bacteria strain isolated from pineapple wine.

10.13

Other value-added products obtained from pineapple waste

A number of small MW solutes as well as possible derivatives from medium to high MW macromolecules can be obtained or derivatized from the pineapple waste. For example, 35 volatile compounds from pineapple rind and fibers

220

Valorization of Fruit Processing By-products

remaining after the juice extraction step were extracted and identified. The principal compounds were esters (37%), alcohols (29%), aldehydes (9%), ketones (9%), and acids (6%) (Barreto et al., 2013), which indicates that these extracts could be used as flavor-enhancing agents. Another group of important commercial interests are polyphenols, which are secondary plant metabolites (Middleton et al., 2000). The major group of phenolic antioxidants includes phenolic acids, flavonoids, and tannins with a range of health benefits including antioxidant, antiallergenic, antimicrobial, antiinflammatory, and antithrombotic effects (Middleton et al., 2000). Quercetin, catechin, and kaempferol are among the widely studied polyphenolic compounds which are found to lower the risk of chronic diseases (Rasouli et al., 2017). Gallic acid, epicatechin, catechin, and ferulic acid have been identified as the main polyphenolic compounds in pineapple peel (Li et al., 2014). Due to their solubility in alcohols, the yield of polyphenols from pineapple peels is improved when methanol is used as the extracting solvent (Hossain and Rahma, 2011). The radical scavenging capacity of one mole of the polyphenolic compounds present in pineapple peel was found to be in the order: gallic acid . epicatechin 5 catechin . ferulic acid (Li et al., 2014). Ferulic acid is another interesting compound with a potential application in the cosmetic and food industries (Ou and Kwork, 2004) since it can also be converted into vanillin (Lun et al., 2014). The process involves the bioconversion of ferulic acid to vanillic acid and vanillin. It is a three-step process (Lun et al., 2014). The first step involves the extraction of ferulic acid from pineapple waste powder that is then heat-treated, mixed with NaOH and NaHSO3, shaken, and centrifuged. The pH of the supernatant is adjusted to 1.8 by adding HCl, and ferulic acid is extracted three times with ethyl acetate. The collected organic layer is concentrated and subject to solid-phase extraction. In the second step, the ferulic acid is transformed into vanillic acid by A. niger I-1472. Such produced vanillic acid is then biotransformed into vanillin by Pycnoporus cinnabarinus MUCL 39533. Vanillin is released into the supernatant after fermentation, which is then collected by adsorption onto an Amberlite XAD-4 resin. Xylitol, as a sugar alcohol, has potential application as a low-calorie sweetener (Dasgupta et al., 2017). Chemically it is less reactive than xylose due to the absence of a reducing carbonyl group, which makes it difficult for toothdecaying bacteria to utilize it in the production of energy and thus eliminates the generation of acid (Nayak et al., 2014). The wide application of xylitol, especially in the food industry, has been attributed to its low glycemic index (Khalid et al., 2012). Health concerns and greater awareness with regards to the importance of naturally derived lowcalorie sweeteners have contributed to the increasing demand for xylitol. Pineapple waste, mainly the peel, is rich in xylan (B25%
35% dry basis), which is a potential substrate for the production of xylitol. Industrially xylitol is produced by catalytic hydrogenation of D-xylose to xylitol under high pressure and temperature (Dasgupta et al., 2017). The process has a great energy demand and involves highly specialized equipment in various and extensive purification steps for xylose and xylitol and the deactivation and recovery of a metal catalyst. For this reason, a more efficient process based on the bioconversion of lignocellulosic hydrolysates has been proposed, however this is still in an exploratory stage (Dasgupta et al., 2017). Another compound of interest that can be derived from pineapple waste is xylooligosaccharides (XOS), which are the oligomers of β-1,4-linked xylose monomers, with various substituents including acetyl, phenolic, and uronic acids. XOS are available commercially, with a degree of polymerization (DP) ranging from 2 to 10. However, for food applications, XOS with a DP of 2
4 are preferred due to their maximum prebiotic effect (Vazquez et al., 2000). Their main advantage over a more established prebiotic, inulin, lies in their greater heat and acid stability which makes them good candidates for use in high-acidity systems such as juices (Vazquez et al., 2000). As a therapeutic XOS also possess antioxidant, antiallergenic, antimicrobial, and immunomodulatory activities (Moure et al., 2006). Due to purity requirements, the current process that could potentially be used for the conversion of hemicellulose from pineapple peel into XOS requires a highly efficient chromatographic method. Unfortunately this approach may not always provide financially viable yields (Choi et al., 2016), and thus further research is required in this area.

10.14

Conclusion

Pineapple waste offers a broad range of great opportunities to recover and produce high-value products. With this focus, particular attention in this overview has been given to some feasible approaches, especially the application of membrane processing, that would allow for the extraction and conversion of pineapple waste into high-value products. It is evident that even pineapple on-farm waste, including mainly pineapple leaves that are rich in cellulose and low in lignin, could be utilized for nanocellulose fiber recovery for specific applications, mainly in pharmacology and medicine for wound healing, drug delivery, and medicinal implants due to biocompatibility, low cytotoxicity, and biodegradability. Pineapple processing waste consisting of peel, pomace, core, and crown could be initially separated using membrane

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technologies and then the range of streams could be further concentrated, such as in case of bromelain, or converted into xylitol, XOS, or biopolymers production, which have great potential applications in the food industry as processing aids, artificial sweeteners, prebiotic supplements, and food packaging material. These valorization approaches not only address the environmental issues but also create commercial opportunities. Certain challenges would persist such as year-round supply; however, these approaches may be used on multiple streams and waste sources.

References Abdullah, Mat, H., 2008. Characterization of solid and liquid pineapple waste. Reaktor 2, 48
52. Arib, R.M.N., Sapuan, S.M., Ahmad, M.M.H.M., Paridah, M.T., Zaman, H.M.D.K., 2006. Mechanical properties of pineapple leaf fibre reinforced polypropylene composites. Mater. Des. 27 (5), 391
396. Arshad, Z.M., Amid, A., Yusof, F., Jaswir, I., Ahmad, K., Loke, S.P., 2014. Bromelain: an overview of industrial application and purification strategies. Appl. Microbiol. Biotechnol. 98 (17), 7283
7297. Babu, B.R., 2008. Aqueous Two Phase Extraction for Purification and Concentration of Biomolecules From Pineapple (Ananas comosus L. Merryl). (PhD thesis). University of Mysore, Karnataka, India. Babu, B.R., Rastogi, N.K., Raghavarao, K.S.M.S., 2008. Liquid
liquid extraction of bromelain and polyphenol oxidase using aqueous two-phase system. Chem. Eng. Process. Process Intensif. 47 (1), 83
89. Baiano, A., 2014. Recovery of biomolecules from food wastes—a review. Molecules 19, 14821
14842. Bala, M., Ismail, N.A., Mel, M., Jami, M.S., Salleh, M.H., Amid, A., 2012. Bromelain production: current trends and perspective. Arch. Sci. 65 (11), 369
399. Ban-Koffi, L., Han, Y.W., 1990. Alcohol production from pineapple waste. World J. Microbiol. Biotechnol. 6, 281
284. Banerjee, A., Chintagunta, A., Ray, S., 2017. A cleaner and eco-friendly bioprocess for enhancing reducing sugar production from pineapple leaf waste. J. Clean. Prod. 149, 387
395. Bardiya, N., Somayaji, D., Khanna, S., 1996. Biomethanation of banana peel and pineapple waste. Bioresour. Technol. 58, 73
76. Barreto, L.C.O., Moreira, J.J.S., Santos, J.A.B., Narain, N., Santos, R.A.R., 2013. Characterization and extraction of volatile compounds from pineapple (Ananas comosus L. Merril) processing residues. Food Sci. Technol. (Campinas) 33 (4), 638
645. Barrett, A., Rawlings, N., Woessner, J., 2013. Handbook of Proteolytic Enzymes, third ed. Academic Press, eBook ISBN 9780123822208. Benucci, I., Liburdi, K., Garzillo, A.M.V., Esti, M., 2011. Bromelain from pineapple stem in alcoholic-acid buffers for wine application. Food. Chem. 124 (4), 1349
1353. Bhattacharyya, B.K., 2008. Bromelain—an overview. Nat. Prod. Rad. 7, 359
363. Boobrad, D., Reanma, K., Nlamsup, H., 2006. Extraction and physicochemical characteristics of acid-soluble pectin from raw papaya (Carica papaya) peel. Chiang Mai J. Sci. 33, 129
135. Chakravarthy, P.K., Acharya, S., 2012. Efficacy of extrinsic stain removal by novel dentifrice containing papain and bromelain extracts. J. Young Pharm. 4 (4), 245
249. Chao, M.A., Mao-Yu, W., Qiao, X., Song, Y., Zhao, Y., 2009. Study on purification of stem bromelain by nano-TiO2 and ultrafiltration. Food Sci. Technol. 34 (4), 167
170. Chaurasiya, R.S., Hebbar, U.H., 2013. Extraction of bromelain from pineapple core and purification by RME and precipitation methods. Sep. Purif. Technol. 111, 90
97. Cheang, B., Zydney, A.L., 2004. A two-stage ultrafiltration process for fractionation of whey protein isolate. J. Membr. Sci. 231, 159
167. Chen, J., Tetrault, J., Ley, A., 2008. Comparison of standard and new generation hydrophobic interaction chromatography resins in the monoclonal antibody purification process. J. Chromatogr. A 1177, 272
281. Cheryan, M., 1986. Ultrafiltration Handbook. Technomic Publishing Co. Inc, Pennsylvania, PA. Choi, J., Park, H., Park, C., Wang, N., Mun, S., 2016. Highly efficient recovery of xylobiose from xylooligosaccharides using a simulated moving bed method. J. Chromatogr. A 1465, 143
154. Chumee, J., Khemmakama, P., 2014. Carboxymethyl cellulose from pineapple peel: useful green bioplastic. Adv. Mater. Res. 979, 366
369. Constenla, D., Lozano, J.E., 2003. Kinetic model of pectin demethylation. Latin Am. Appl. Res. 33, 91
96. Costa, H.B., Fernandes, P.M.B., Roma˜o, W., Ventura, J.A., 2014. A new procedure based on column chromatography to purify bromelain by ion exchange plus gel filtration chromatographies. Ind. Crops Prod. 59, 163
168. Dacera, D.D.M., Babe, L.S., 2008. Removal of heavy metals from contaminated sewage sludge using Aspergillus niger fermented raw liquid from pineapple wastes. Bioresour. Technol. 99, 682
1689. Dasgupta, D., Bandhu, S., Adhikari, D., Ghosh, D., 2017. Challenges and prospects of xylitol production with whole cell bio-catalysts: a review. Microbiol. Res. 197, 9
21. Datta, D., Bhattacharjee, S., Nath, A., Das, R., Bhattacharjee, C., Datta, S., 2009. Separation of ovalbumin from chicken egg white using two-stage ultrafiltration technique. Sep. Purif. Technol. 66 (2), 353
361. Devakate, R.V., Patil, V.V., Waje, S.S., Thorat, B.N., 2009. Purification and drying of bromelain. Sep. Purif. Technol. 64 (3), 259
264. Devi, L.U., Bhagawan, S.S., Thomas, S., 1998. Mechanical properties of pineapple leaf fiber-reinforced polyester composites. J. Appl. Polym. Sci. 64, 1739
1748.

222

Valorization of Fruit Processing By-products

Diaz-Vela, J., Totosaus, A., Cruz-Guerrero, A.E., Perez-Chabela, M.L., 2013. In vitro evaluation of the fermentation of added-value agroindustrial byproducts: cactus pear (Opuntia ficus indica L.) peel and pineapple (Ananas comosus) peel as functional ingredients. Int. J. Food Sci. Technol. 48, 1460
1467. Doko, M.B., Bassani, V., Casadebaig, J., Cavailles, L., Jacob, M., 1991. Preparation of proteolytic enzyme extracts from Ananas comosus L., Merr. fruit juice using semipermeable membrane, ammonium sulfate extraction, centrifugation and freeze-drying processes. Int. J. Pharm. 76 (3), 199
206. Dufresne, A., 2013. Nanocellulose: a new ageless bionanomaterial. Mater. Today 16 (6), 220
227. FAOSTAT, 2015. World’s production of pineapple. Retrieved on March 11, 2015, from Food and Agricultural Organization (FAO) website ,http:// faostat3.fao.org/browse/Q/QC/E.. Feijoo-Siota, L., Villa, T.G., 2010. Native and biotechnologically engineered plant proteases with industrial applications. Food Bioprocess Technol. 4 (6), 1066
1088. Feng, J., Nguyen, S.T., Fan, Z., Duong, H.M., 2015. Advanced fabrication and oil absorption properties of super-hydrophobic recycled cellulose aerogels. Chem. Eng. J. 270, 168
175. Fileti, A.M.F., Fischer, G.A., Tambourgi, E.B., 2010. Neural modeling of bromelain extraction by reversed micelles. Braz. Arch. Biol. Technol. 53 (2), 455
463. Gimeno, C., Segui, L., Fito, P., 2010. Valorisation of industrial pineapple residues: bromelain separation followed by bioethanol fermentation. In: International Conference on Food Innovation (Food Innova), Valencia, Spain. International Union of Food Science and Technology. Girard, B., Fukumoto, L.R., 2000. Membrane processing of fruit juices and beverages: a review. Crit. Rev. Biotechnol. 20 (2), 112
175. Grassin, C., Fauquembergue, P., 1996. Application of pectinases in beverages. In: Visser, J., Voragen, A.G.J. (Eds.), Progress in Biotechnology. Elsevier, Amsterdam, pp. 453
462. Haafiz, M.K.M., Hassan, A., Zakaria, Z., Inuwa, I.M., 2014. Isolation and characterization of cellulose nanowhiskers from oil palm biomass microcrystalline cellulose. Carbohydr. Polym. 103, 119
125. Hale, L.P., Greer, P.K., Trinh, C.T., James, C.L., 2005. Proteinase activity and stability of natural bromelain preparations. Int. Immunopharmacol. 5 (4), 783
793. Hameed, B.H., Krishni, R.R., Sata, S.A., 2009. A novel agricultural waste adsorbent for the removal of cationic dye from aqueous solutions. J. Hazard. Mater. 162, 305
311. Hebbar, U.H., Sumana, B., Raghavarao, K.S.M.S., 2008. Use of reverse micellar systems for the extraction and purification of bromelain from pineapple wastes. Bioresour. Technol. 99 (11), 4896
4902. Hebbar, U.H., Sumana, B., Hemavathi, A.B., Raghavarao, K.S.M.S., 2012. Separation and purification of bromelain by reverse micellar extraction coupled ultrafiltration and comparative studies with other methods. Food Bioprocess Technol. 5 (3), 1010
1018. Hemawathi, A.B., Hebbar, H.U., Raghavaro, K., 2007. Reverse micellar extraction of bromelain from Ananas comosus L. Merryl. J. Chem. Technol. Biotechnol. 82, 985
992. Hinkova, A., Bubnı´k, Z., Kadlec, P., Pridal, J., 2002. Potentials of separation membranes in the sugar industry. Sep. Purif. Technol. 26 (1), 101
110. Hofs, B., Ogier, J., Vries, D., Beerendonk, E.F., Cornelissen, E.R., 2011. Comparison of ceramic and polymeric membrane permeability and fouling using surface water. Sep. Purif. Technol. 79 (3), 365
374. Hossain, M., Rahma, S., 2011. Total phenolics, flavonoids, and antioxidant activity of tropical fruit pineapple. Food Res. Int. 44 (3), 672
676. Idris, A., Suzana, W., 2006. Effect of sodium alginate concentration, bead diameter, initial pH and temperature on lactic acid production from pineapple waste using immobilized Lactobacillus delbrueckii. Process Biochem. 41 (5), 1117
1123. Illanes, A., 2008. Enzyme production. In: Illanes, A. (Ed.), Enzyme Biocatalysis. Springer, The Netherlands, pp. 57
106. Imandi, S., Bandaru, V., Somalanka, S., Bandaru, S., Garapati, H., 2008. Application of statistical experimental designs of medium constituents for the production of citric acid from pineapple waste. Bioresour. Technol. 99 (10), 4445
4450. Isa, M.H.M., Coraglia, D.E., Frazier, R.A., Jauregi, P., 2007. Recovery and purification of surfactin from fermentation broth by a two-step ultrafiltration process. J. Memb. Sci. 296 (1
2), 51
57. Jervis, L., Pierpoint, W.S., 1989. Purification technologies for plant proteins. J. Biotechnol. 11 (2
3), 161
198. Jin, B., Yin, P., Ma, Y., Zhao, L., 2005. Production of lactic acid and fungal biomass by Rhizopus fungi from food processing waste streams. J. Ind. Microbiol. Biotechnol. 32 (11
12), 678
686. Jorfi, M., Foster, E., 2015. Recent advances in nanocellulose for biomedical applications. J. Appl. Polym. Sci. 132 (14). Available from: https://doi. org/10.1002/app.41719. Jusoha, N., Othman, N., Idris, A., Nasruddin, A., 2014. Characterization of liquid pineapple waste as carbon source for production of succinic acid. J. Teknol. 69 (4), 11
13. Jutamongkon, R., Charoenrein, S., 2010. Effect of temperature on the stability of fruit bromelain from smooth cayenne pineapple. Kasetsart J. Nat. Sci. 44, 943
948. Ketnawa, S., Sai-Ut, S., Theppakorn, T., Chaiwut, P., Rawdkuen, S., 2009. Partitioning of bromelain from pineapple peel (Nang Lae cultv.) by aqueous two phase system. Asian J. Food Agro-Ind. 2 (4), 457
468. Ketnawa, S., Rawdkuen, S., Chaiwut, P., 2010. Two phase partitioning and collagen hydrolysis of bromelain from pineapple peel Nang Lae cultivar. Biochem. Eng. J. 52 (2
3), 205
211. Ketnawa, S., Chaiwu, T.P., Rawdkuen, S., 2011. Aqueous two-phase extraction of bromelain from pineapple peels (‘PhuLae’ cultv.) and its biochemical properties. Food Sci. Biotechnol. 20 (5), 1219
1226. Ketnawa, S., Chaiwut, P., Rawdkuen, S., 2012. Pineapple wastes: a potential source for bromelain extraction. Food Bioprod. Process. 90, 385
391. Khalid, E., Johan, S., Hele´n, J., Jan, S., 2012. Calorimetric and relaxation properties of xylitol-water mixtures. J. Chem. Phys. 136 (10), 104508.

Pineapple Chapter | 10

223

Kliemann, E., Numes, S.K., Amante, E.R., Prudencio, E.S., Teofilo, R.F., Ferreira, M.C., et al., 2009. Optimization of pectin acid extraction from passion fruit peel (Passiflora edulis) using response surface methodology. Int. J. Food Sci. Technol. 44, 476
483. Knill-Jones, R.P., Pearce, H., Batten, J., Williams, R., 1970. Comparative trial of Nutrizym in chronic pancreatic insufficiency. BMJ 4, 21
24. Koh, J., Kang, S.M., Kim, S.J., Cha, M.K., Kwon, Y.J., 2006. Effect of pineapple protease on the characteristics of protein fibres. Fibers Polym. 7 (2), 180
185. Kong, X., Zhou, H., Qian, H., 2007. Enzymatic hydrolysis of wheat gluten by proteases and properties of the resulting hydrolysates. Food. Chem. 102 (3), 759
763. Kumar, D., Jain, V., Shanker, G., Srivastava, A., 2003. Utilisation of fruit waste for citric acid production by solid state fermentation. Process Biochem. 38 (12), 1725
1729. Kumar, S., Hemavathi, A.B., Umesh Hebbar, H., 2011. Affinity based reverse micellar extraction and purification of bromelain from pineapple (Ananas comosus L. Merryl) waste. Process Biochem. 46, 1216
1220. Larrauri, J.A., Ruperez, P., Calixto, F.S., 1997. Pineapple shell as a source of dietary fiber with associated polyphenols. J. Agric. Food Chem. 45, 4028
4031. Laufenberg, G., Kunz, B., Nystroem, M., 2003. Transformation of vegetable waste into value added products: (A) the upgrading concept; (B) practical implementations. Bioresour. Technol. 87 (2), 167
198. Lee, S.-J., Kim, J.-H., 2014. Differential natural organic matter fouling of ceramic versus polymeric ultrafiltration membranes. Water Res. 48, 43
51. Lee, M., Wu, Z., Li, K., 2015. Advances in ceramic membranes for water treatment. In: Basile, A., Rastogi, A.C.K. (Eds.), Advances in Membrane Technologies for Water Treatment. Woodhead Publishing, Oxford, pp. 43
82. Lee, S., Park, G., Amy, G., Hong, S.-K., Moon, S.-H., Lee, D.-H., et al., 2002. Determination of membrane pore size distribution using the fractional rejection of nonionic and charged macromolecules. J. Membr. Sci. 201, 191
201. Lee, S.J., Dilaver, M., Park, P.K., Kim, J.H., 2013. Comparative analysis of fouling characteristics of ceramic and polymeric microfiltration membranes using filtration models. J. Membr. Sci. 432, 97
105. Leung, V., Ko, F., 2011. Biomedical applications of nanofibers. Polym. Adv. Technol. 22 (3), 350
365. Li, T., Shen, P., Liu, W., Liu, C., Liang, R., Yan, N., et al., 2014. Major polyphenolics in pineapple peels and their antioxidant interactions. Int. J. Food Prop. 17 (8), 1805
1817. Lipnizki, F., 2010. Chapter 7—membrane processes for the production of bulk fermentation products. In: Cui, Z.F., Muralidhara, H.S. (Eds.), Membrane Technology, A Practical Guide to Membrane Technology and Applications in Food and Bioprocessing. Elsevier Ltd, ButterworthHeinemann, pp. 121
153. Lopes, F.L.G., Ju´nior, S., Baptista, J., Souza, R.R.D., Ehrhardt, D.D., Santana, J.C.C., et al., 2009. Concentration by membrane separation processes of a medicinal product obtained from pineapple pulp. Braz. Arch. Biol. Technol. 52 (2), 457
464. Lopes, F.L.G., Sbruzzi, D., Barros, K.V.G., Ferreira, J.F., Santana, J.C.C., Souza, R.R.D., et al., 2012. Viability in the production of a drug extracted from Ananas comosus by a flat membrane system. Braz. Arch. Biol. Technol. 55 (3), 465
470. Lun, O.K., Wai, T.B., Ling, L.S., 2014. Pineapple cannery waste as a potential substrate for microbial biotransformation to produce vanillic acid and vanillin. IFRJ 21 (3), 953
958. Manzoor, Z., Nawaz, A., Mukhtar, H., Haq, I., 2016. Bromelain: methods of extraction, purification and therapeutic applications. Braz. Arch. Biol. Technol. 56. Available from: https://doi.org/10.1590/1678-4324-2016150010. Menon, M., Selvakumar, R., Kumar, P., Ramakrishna, S., 2017. Extraction and modification of cellulose nanofibers derived from biomass for environmental application. RSC Adv. 7 (68), 42750
42773. Middleton, E., Kandaswami, C., Theoharides, T., 2000. The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer. Pharmacol. Rev. 52 (4), 673
751. Mohamadzadeh, J., Mahoonak, A.R., Yaghbani, M., Aalami, M., 2010. Extraction of pectin from sunflower head residues of selected Iranian cultures. World Appl. Sci. J. 8, 21
24. Mohamed, S., Hasan, Z., 1995. Extraction and characterisation of pectin from various tropical agrowastes. ASEAN Food J. 10 (2), 43
50. Moure, A., Gullon, P., Dominguez, H., Parajo, J.C., 2006. Advances in the manufacture, purification and applications of xylooligosaccharides as food additives and nutraceuticals. Process Biochem. 41 (9), 1913
1923. Murachi, T., 1970. Bromelain enzymes. In: Perlmann, G.E., Lorand, L. (Eds.), Methods in Enzymology, vol. 19. Elsevier Inc, pp. 273
284. Murachi, T., Yasui, M., Yasuda, Y., 1964. Purification and physical characterization of stem bromelain. Biochemistry 3 (1), 48
55. Nadzirah, K.Z., Zainal, S., Noriham, A., Normah, I., 2013. Efficacy of selected purification techniques for bromelain. Int. Food Res. J. 20 (1), 43
46. Nayak, P., Nayak, U., Khandelwal, V., 2014. The effect of xylitol on dental caries and oral flora. Clin. Cosmet. Invest. Dent. 6, 89
94. Nie, H., Li, S., Zhou, Y., Chen, T., He, Z., Su, S., et al., 2008. Purification of bromelain using immobilized metal affinity membranes. J. Biotechnol. 136, S416. Nigam, J.N., 1999. Continuous ethanol production from pineapple cannery waste. J. Biotechnol. 72, 197
202. Nigam, J.N., 2000. Optimization of dilution rate for the production of value added product and simultaneous reduction of organic load from pineapple cannery waste. World J. Microbiol. Biotechnol. 18, 301
305. Nor, M.Z.M., 2017. Membrane Based Process for the Extraction of Bromelain From Pineapple Waste (PhD thesis). College of Health and Biomedicine, Victoria University, Melbourne, Australia. Nor, M.Z.M., Ramchandran, L., Duke, M., Vasiljevic, T., 2015. Characteristic properties of crude pineapple waste extract for bromelain purification by membrane processing. J. Food Sci. Technol. 52 (11), 7103
7112.

224

Valorization of Fruit Processing By-products

Nor, M.Z.M., Ramchandran, L., Duke, M., Vasiljevic, T., 2016. Separation of bromelain from crude pineapple waste mixture by a two-stage ceramic ultrafiltration process. Food Bioprod. Process. 98, 142
150. Nor, M.Z.M., Ramchandran, L., Duke, M., Vasiljevic, T., 2017. Application of membrane-based technology for purification of bromelain. Int. Food Res. J. 24 (4), 1685
1696. Normah, L., Ku Hasnah, K.A., 2000. Pectin content of selected local fruit by-products. J. Trop. Agric. Food 28 (2), 195
201. Novaes, L.C.L., Ebinuma, V.C.S., Mazzola, P.G., Junior, A.P., 2013. Polymer-based alternative method to extract bromelain from pineapple peel waste. Int. Union Biochem. Mol. Biol. 60 (5), 527
535. Novaes, L.C.L., Jozala, A.F., Lopes, A.M., Santos-Ebinuma, V.C., Mazzola, P.G., Junior, A.P., 2016. Stability, purification, and applications of bromelain: a review. Biotechnol. Prog. 32 (1), 5
13. Nunes, M.C.N., Emond, J.P., Rauth, M., Dea, S., Chau, K.V., 2009. Environmental conditions encountered during typical consumer retail display affect fruit and vegetable quality and waste. Postharvest Biol. Tec. 51, 232
241. Ou, S., Kwork, K., 2004. Review ferulic acid: pharmaceutical functions, preparation and applications in foods. J. Sci. Food Agric. 84, 1261
1269. Ozlen, S.N., 1995. Cosmetic composition containing alpha hydroxyacids, salicylic acid and enzyme mixture of bromelain and papain. US patent. Longevity Network Ltd., Handerson, United States, Nev 1
6. ,http://www.freepatentsonline.com/. Pavan, R., Jain, S., Kumar, A., 2012. Properties and therapeutic application of bromelain: a review. Biotechnol. Res. Int. 2012, 1
6. Rabelo, A.P., Tambourgi, E.B., Pessoa Jr., A., 2004. Bromelain partitioning in two-phase aqueous systems containing PEO-PPO-PEO block copolymers. J. Chromatogr. B: Anal. Technol. Biomed. Life Sci. 807 (1), 61
68. Ramalingam, C., Srinath, R., Nasimun, N., 2012. Isolation and characterization of bromelain from pineapple (Ananas comosus) and comparing its anti-browning activity on apple juice with commercial antibrowning agents. Elixir Food Sci. 45, 7822
7826. Rani, D., Nand, K., 2004. Ensilage of pineapple processing waste for methane generation. Waste Manag. 24 (5), 523
528. Rasouli, H., Farzaei, M., Khodarahmi, R., 2017. Polyphenols and their benefits: a review. Int. J. Food Prop. 20, 1700
1741. Rathnavelu, V., Alitheen, N.B., Subramaniam Sohila, S., Kanagesan, S., Ramesh, R., 2016. Potential role of bromelain in clinical and therapeutic applications. Biomed. Rep. 5 (3), 283
288. van Reis, R., Zydney, A., 2001. Membrane separations in biotechnology. Curr. Opin. Biotechnol. 12, 208
211. van Reis, R., Gadam, S., Frautschy, L.N., Orlando, S., Goodrich, E.M., Saksena, S., et al., 1997. High performance tangential flow filtration. Biotechnol. Bioeng. 56 (1), 71
82. van Reis, R., Brake, J.M., Charkoudian, J., Burns, D.B., Zydney, A.L., 1999. High-performance tangential flow filtration using charged membranes. J. Membr. Sci. 159, 133
142. Roda, A., De Faveri, D.M., Giacosa, S., Dordoni, R., Lambri, M., 2016a. Effect of pre-treatments on the saccharification of pineapple waste as a potential source for vinegar production. J. Clean. Prod. 112, 4477
4484. Roda, A., De Faveri, D.M., Dordoni, R., Cases, E.V., Jauregui, N.N., Barrachina, A.A.C., et al., 2016b. Pineapple wines obtained from saccharification of its waste with three strains of saccharomyces cerevisiae. J. Food Process. Preserv. ISSN: 1745-4549. Sah, B.N.P., Vasiljevic, T., McKechnie, S., Donkor, O.N., 2015. Effect of refrigerated storage on probiotic viability and the production and stability of antimutagenic and antioxidant peptides in yogurt supplemented with pineapple peel. J. Dairy Sci. 98 (9), 5905
5916. Santos, R., Flauzino Neto, W., Silverio, H., Martins, D., Dantas, N., Pasquini, D., 2013. Cellulose nanocrystals from pineapple leaf, a new approach for the reuse of this agrowaste. Ind. Crops Prod. 50, 707
714. Senthilkumaar, S., Bharathi, S., Nithyanandhi, D., Subburam, V., 2000. Biosorption of toxic heavy metals from aqueous solutions. Bioresour. Technol. 75, 163
165. Silveira, E., Souza-Jr, M.E., Santana, J.C.C., Chaves, A.C., Porto, A.L.F., Tambourgi, E.B., 2009. Expanded bed adsorption of bromelain (E.C. 3.4.22.33) from Ananas comosus crude extract. Braz. J. Chem. Eng. 26 (1), 149
157. Silvestre, M.P.C., Carreira, R.L., Silva, M.R., Corgosinho, F.C., Monteiro, M.R.P., Morais, H.A., 2012. Effect of pH and temperature on the activity of enzymatic extracts from pineapple peel. Food Bioprocess Technol. 5, 1824
1831. Singh, L.R., Devi, Y.R., Devi, S.K., 2003. Enzymological characterization of pineapple extract for potential application in oak tasar (Antheraea proylei J.) silk cocoon cooking and reeling. Electr. J. Biotechnol. 6 (3), 198
207. Soares, P.A.G., Vaz, A.F.M., Correia, M.T.S., Pessoa Jr., A., Carneiro-da-Cunha, M.G., 2012. Purification of bromelain from pineapple wastes by ethanol precipitation. Sep. Purif. Technol. 2138 (98), 389
395. Sossou, S.K., Ameyaph, Y., Karou, S.D., de Souza, C., 2009. Study of pineapple peelings processing into vinegar by biotechnology. Pak. J. Biol. Sci. 12 (11), 859
865. Spir, L.G., Ataide, J.A., Novaes, L.C., Gurpilhares, D., Moriel, P., Silveira, E., et al., 2015. Application of an aqueous two-phase micellar system to extract bromelain from pineapple (Ananas comosus) peel waste and analysis of bromelain stability in cosmetic formulations. Biotechnol. Prog. 31 (4), 937
945. Sruamisri, S., 2007. Agricultural wastes as dairy feed in Chiang Mai. Anim. Sci. J. 78 (4), 335
341. Takahashi, N., Murachi, T., 1976. Stem bromelain. Isolation and purification; preparation and characterization of the carbohydrate portion. Methods Carbohydr. Chem. 7, 175
184. Tanaka, K., Hilary, Z.D., Ishizaki, A., 1999. Investigation of the utility of pineapple juice and pineapple waste material as low-cost substrate for ethanol fermentation by Zymomonas mobilis. J. Biosci. Bioeng. 87 (5), 642
646. Tanuja, S., Viji, P., Zynudheen, A.A., Joshy, C., 2012. Composition, functional properties and antioxidative activity of hydrolysates prepared from the frame meat of striped catfish (Pangasianodon hypophthalmus). Egypt. J. Biol. 14 (1), 27
35.

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Tilay, A., Bule, M., Kishenkumar, J., Annapure, U., 2008. Preparation of ferulic acid from agricultural wastes: its improved extraction and purification. J. Agric. Food Chem. 56, 7664
7668. Tochi, B.N., Wang, Z., Xu, S.-Y., Zhang, W., 2009. The influence of a pectinase and pectinase/hemicellulases enzyme preparations on percentage pineapple juice recovery, particulates and sensory attributes. Pak. J. Nutr. 8 (8), 1184
1189. Tomankova, O., Kopecny, J., 1995. Prediction of feed protein degradation in the rumen with bromelain. Anim. Feed Sci. Technol. 53 (1), 71
80. Tran, A., 2006. Chemical analysis and pulping study of pineapple crown leaves. Ind. Crops Prod. 24 (1), 66
74. Ueno, T., Ozawa, Y., Ishikawa, M., Nakanishi, K., Kimura, T., 2003. Lactic acid production using two food processing wastes, canned pineapple syrup and grape invertase, as substrate and enzyme. Biotechnol. Lett. 25 (7), 573
577. Upadhyay, A., Lama, J.P., Tawata, S., 2010. Utilization of pineapple waste: a review. J. Food Sci. Technol. Nepal 6, 10
18. Upadhyay, A., Chompoo, J., Araki, N., Tawata, S., 2012. Antioxidant, antimicrobial, 15-LOX, and AGEs inhibitions by pineapple stem waste. J. Food Sci. 71 (1), H9
H15. Vazquez, M.J., Alonso, J.L., Dominguez, H., Parajo, J.C., 2000. Xylooligosaccharides: manufacture and application. Trends Food Sci. Technol. 11 (11), 387
393. Vicente, F.A., Luciana, L.D., Pessoa Jr., A., Ventura, S.P.M., 2016. Recovery of bromelain from pineapple stem residues using aqueous micellar twophase systems with ionic liquids as co-surfactants. Process Biochem. 51, 528
534. Wang, C.H., Lin, P.J., Chang, J.S., 2006. Fermentative conversion of sucrose and pineapple waste into hydrogen gas in phosphate-buffered culture seeded with municipal sewage sludge. Process Biochem. 41, 1353
1358. Weng, C.H., Lin, Y.T., Tzeng, T.W., 2009. Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder. J. Hazard. Mater. 170, 417
424. Yamada, F., Takahashi, N., Murachi, T., 1976. Purification and characterization of a proteinase from pineapple fruit, fruit bromelain FA2. J. Biochem. 79 (6), 1223
1234. Yin, L., Sun, C.K., Han, X., Xu, L., Xu, Y., Yan Qi, Y., et al., 2011. Preparative purification of bromelain (EC 3.4.22.33) from pineapple fruit by high-speed counter-current chromatography using a reverse-micelle solvent system. Food Chem. 129, 925
932.

Further reading Ako, H., Cheung, A.H., Matsuura, P.K., 1981. Isolation of a fibrinolysis enzyme activator from commercial bromelain. Arch. Int. Pharmacodyn. The´r. 254 (1), 157
167. Kaur, B., Chakraborty, D., Kumar, B., 2013. Phenolic biotransformations during conversion of ferulic acid to vanillin by lactic acid bacteria. Biomed. Res. Int. 590359. Available from: https://doi.org/10.1155/2013/590359. Nigam, J.N., 1998. Single cell protein from pineapple cannery effluent. World J. Microbiol. Biotechnol. 14, 693
696. Roda, A., De Faveri, D., Dordoni, R., Lambri, M., 2014. Vinegar production from pineapple wastes—preliminary saccharification trials. Chem. Eng. Trans. 37, 607
612.

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Chapter 11

Pink guava Ying Ping Chang1, Kwan Kit Woo2 and Charles Gnanaraj1 1

Faculty of Science, Department of Chemical Science, Universiti Tunku Abdul Rahman, Negeri Perak, Malaysia, 2Lee Kong Chian Faculty of

Engineering and Science, Department of Chemical Engineering, Universiti Tunku Abdul Rahman, Negeri Perak, Malaysia

Chapter Outline 11.1 Introduction 11.1.1 About pink guava 11.1.2 Pink guava by-products 11.2 Functional properties and health-promoting effects of pink guava phytochemical constituents 11.3 Possible routes to upgrade pink guava by-products commercialization values 11.3.1 Phytochemical extraction

11.1

227 227 228 229 231 233

11.3.2 Prebiotics ingredients 11.3.3 Substrate for fermentation 11.4 Processing method to minimize the waste after extraction 11.5 Constraints and challenges in reutilizing pink guava by-products 11.6 Further research to fill the knowledge gap References

240 241 242 245 247 248

Introduction

Guava (Psidium guajava L.) is a tropical fruit that originated in the American tropics. Guava fruits are well accepted by consumers due to their rich aroma and large amount of vitamin C, minerals, and dietary fibers. At present they are distributed throughout the tropical and subtropical areas in the world. Two types of guava fruit, the white- and the pinkfleshed guava are produced on a large scale. White-flesh guava is reported to be a better source of vitamin C than the pink-flesh guava (142.6 mg in comparison with 72.2 mg/100 g). It is also rich in phenolics (Sidhu, 2006), while the pink-flesh guava exerted greater antioxidant activities (Flores et al., 2015). Generally, guava fruits are consumed fresh or subjected to industrial preservation or processing. Processed pink guava puree can be further used in juice, nectar, guava cheese, jams, and jellies production. Global production of guava increases from year to year and achieved 46.5 million metric tons in year 2016 (Tridge, 2018).

11.1.1

About pink guava

Pink guava varieties which are commonly cultivated include Barbie Pink, Homestead, Sardina 1, Sardina 2 (Flores et al., 2015), Beaumont (Kong and Ismail, 2011; Pommer and Murakami, 2009), Criolla (Rojas-Garbanzo et al., 2017), Lalit (Killadi et al., 2018; Pommer and Murakami, 2009), Enana Roja (Pino et al., 2008), and Paluma (Del’Arco and de Sylos, 2018). Adrian et al. (2012) evaluated pink-flesh guava composition for forage application and observed that pink-flesh guava contained 6.83% crude protein, 3.61% ash, 52.65% neutral detergent fiber, 47.14% acid detergent fiber, 5.65% hemicellulose; 70.36% total digestible energy, and 36.03% in vitro organic matter digestibility (dried weight basis, db). They concluded that guava fruits possess low in vitro organic digestibility and it is not nutritionally sufficient to be the sole source of feed for livestock. The phytochemicals present in pink guava are lycopene, carotenoid, and flavonoids. Wilberg and Rodriguez-Amaya (1995) revealed that pink guava contained a much higher content of lycopene (44.80
60.6 μg/g) than that of mango or papaya (18.60
28.60 μg/g). Its β-carotene content (3.02
5.84 μg/g) was higher than that of papaya (0.80
1.76 μg/g).

Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00011-3 © 2020 Elsevier Inc. All rights reserved.

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Valorization of Fruit Processing By-products

About 60 phenolic compounds were identified and classified as ellagitannins, flavones, flavonols, flavanols, proanthocyanidins, dihydrochalcones, and anthocyanidin (Rojas-Garbanzo et al., 2017), which contributed to the high antioxidant activities (Flores et al., 2015). Meanwhile, there are more than 50 volatile compounds that give the distinct aroma and flavor to guava fruits. Aromatic compounds including terpenoic hydrocarbons and 3-hydroxy-2-butanone have been identified and quantified in pink guava fruits and puree (Jorda´n et al., 2003; Steinhaus et al., 2009). Some sulfurcontaining constituents such as 3-mercaptohexanol and 3-mercaptohexyl acetate are believed to contribute to the overall aroma (Clery and Hammond, 2008).

11.1.2

Pink guava by-products

There are three main stages in pink guava puree production. The cutting and crushing, sieving, and decanting produce by-products of different sizes and compositions. These by-products contributed about 25% of the whole fruits and are discarded as solid waste (Chang et al., 2017; Kong and Ismail, 2011). Significant amounts of phytochemicals and essential nutrients are present in these by-products. Thus different techniques have been suggested to extract bioactive components from fruit and vegetable wastes for potential utilization (Sagar et al., 2018). In view of the emerging demand for food, food ingredients, and feeds, research on pink guava wastes’ composition and bioactivity have intensified in recent years to maximize resource utilization. Kong and Ismail (2011) found high lycopene contents in pink guava (Sungkai Beaumont var.) decanter by-products (5.51 mg/100 g) in comparison with those of the whole fruit (3.78 mg/100 g) (wet weight basis, wwb), while Del’Arco and de Sylos (2018) reported total carotenoid content of pink guava (Paluma var.) ranged from 6.64 to 8.66 mg lycopene/100 g of the whole fruit, and 11.53 to 13.86 mg lycopene/100 g of the pulp. Killadi et al. (2018) reported lower lycopene content in the peel (0.47 mg/100 g) and the pulp (0.34 mg/100 g) of pink guava (Lalit var.). Lycopene functions as a lipophilic antioxidative compound which assists cells in coping with oxidative stress, thus preventing cellular and DNA damage and downregulating inflammatory mediators (Vasconcelos et al., 2017). Thus pink-flesh guava wastes have great potential to be a source of lycopene for nutraceutical product development. There are other phytochemicals such as phytate (Lim et al., 2018), phenolic compounds like flavonoids (Kong et al., 2010b), and many more phytochemicals which possibly are present in pink guava by-products (Rojas-Garbanzo et al., 2017) that could be extracted and further explored. Pink guava by-products are also rich in dietary fiber and low molecular weight carbohydrate (Lim et al., 2018; Mhd Abd Kader et al., 2016), similar to the whole fruit of pink-flesh guava (Adrian et al., 2012). Our recent study on three guava by-products which were generated during guava puree production revealed that crude fiber content in guava byproducts was within a range of 31.53%
53.78% (db). Cellulose (21.66%
29.78%, db) and low molecular weight carbohydrate (9.01%
17.19%, db) were the predominant carbohydrates found in guava by-products (Lim et al., 2018). The physical appearance of the three types of by-products was different, before drying and grinding. The refiner (particle size B1.2 mm), appeared seed-like with fibrous material; the siever (particle size B0.8 mm) had a greenish-brown color resembling the guava peel; while the decanter (particle size ,0.8) was pinkish brown, resembling the guava fruit pulp. Fig. 11.1 shows the different dried by-products from pink guava puree production. Decanter by-products contained stone cells (Weinert and van Wyk, 1988) and tended to clump together due to the fine particle size. The by-products were ground to ,250 μm prior to physicochemical study. Dietary fiber possesses important physicochemical properties in attenuating blood glucose and blood cholesterol levels, and thus plays an important role in human diet and health (Fuller et al., 2016). Pink guava by-products contained total dietary fiber in a range from 18.63% to 29.86% (wwb) in which 15.79%
28.58% was insoluble dietary fiber while

FIGURE 11.1 Freeze-dried (A) refiner; (B) siever; and (C) decanter.

Pink guava Chapter | 11

229

1.02%
1.67% was soluble dietary fiber (Mhd Abd Kader et al., 2016). It may not be feasible to be applied as a sole feedstock for livestock, due to the low digestibility. However, polysaccharides extracted from pink guava whole fruit have shown antiinflammatory, antiatherogenesis, and hepatoprotective activity (Alias et al., 2015; Kamarazaman et al., 2017) and similar complex carbohydrates may be found in pink guava by-products, which is worth further investigation. On the other hand, low molecular weight carbohydrates, including glucose, sucrose, and fructose (Mhd Abd Kader et al., 2016), and prebiotics activity (Lim et al., 2018) have been detected and quantified in pink guava by-products. Such materials can be utilized and incorporated into animal feeds as a source of energy for metabolism; and act synergistically with probiotic strains in the host’s gastrointestinal tract to boost the immune system of the host (M’Sadeq et al., 2015), respectively.

11.2 Functional properties and health-promoting effects of pink guava phytochemical constituents Phytochemicals are secondary metabolites with unspecified functions for protection and support in plants. These metabolites are also present in plant-based food products like fruits, grains, and vegetables, and hence are known as dietary phytochemicals. Knowledge of the medicinal values of phytochemicals was developed to produce pharmaceutical drugs for a range of medical conditions including cancers, cardiovascular diseases, neurodegenerative ailments, and many more. Numerous clinical and preclinical trials were done to ascertain the pharmacological relevance of dietary phytochemicals from food intake (Gnanaraj et al., 2017). Phytochemicals can be categorized into polyphenols, comprising flavonoids, lignans, and phenolic acids; terpenoids, which contribute to volatile aroma; and other secondary metabolites. Fruits and vegetables are not only rich in phytochemicals but also contain micronutrients and dietary fibers. Micronutrients are classes of vitamins, minerals, and trace elements, whereas dietary fibers are constituents of plants that have low digestibility and absorption when consumed. Examples of dietary fibers include pectins, gums, hemicelluloses, celluloses, and lignins. It is assumed that whole food products such as fruits, vegetables, or grains, contribute to human health benefits through a synergistic effect among the phytochemicals, dietary fibers, and micronutrient contents (Probst et al., 2017). Various parts from the guava plant have been traditionally used as medication to treat several ailments including dermatosis, epilepsy, diarrhea, menstrual problems, and hysteria, which can be related to its phytochemical contents (Gutie´rrez et al., 2008). Ascorbic acid (vitamin C) concentration in pink guava is one of the highest among all the fruits. A strong presence of ascorbic acid in pink guava was proven with the free radical scavenging and reducing activity in numerous antioxidant tests (Flores et al., 2015). The antioxidant activities of pink guava are not specific to ascorbic acid but also due to the presence of other phenolic compounds like apigenin, myricetin, anthocyanins, and ellagic acid. The pink coloration in the flesh of the fruit is contributed by the presence of the major carotenoid, lycopene. Growing evidence also points to lycopene’s beneficial effects in the maintenance of cardiovascular function and health (CostaRodrigues et al., 2018). It is interesting to note that lycopene-loaded nanoliposomes were able to ameliorate the effects of freeze
thawing stress on cryopreserved spermatozoa of rooster (Najafi et al., 2018). Carotenoids are well known for their antioxidant activity and health benefits. Important pharmacological relevance of carotenoids is notable for the prevention of severe ailments like cancer and stroke (Kadian and Garg, 2012). Other types of carotenoids present in pink guava are phytofluene, lutein, rubixanthin, neochrome, β-carotene, γ-carotene, β-cryptoxanthin, and cryptoflavin (Mercadante et al., 1999). A review of phytochemicals as potential therapeutic drugs for chemoprevention and antiproliferation of cancer cells stated that methoxylated flavonoids have potent bioavailability and cancer therapeutic effects as compared to hydroxylated flavonoids (Androutsopoulos et al., 2010). There is a need to further illuminate the extensive metabolic pathways of methoxylated flavonoids in vivo to prove the pharmacological ability of these natural products in the human diet, at doses well within physiological range. Due to the high content of phytochemicals and dietary fibers in pink guava, the industrial by-products from the processing of this fruit are also rich in antioxidants and dietary fibers. As mentioned previously, pink guava by-products are rich in lycopene and phenolic compound contents. During the fruit processing, major dietary fiber contents from the flesh of pink guava are discarded in the form of coarse pulp. Seeds of pink guava have a high content of insoluble dietary fiber and moderate amounts of fat and protein. The peel of pink guava contains high amounts of phenolic compounds, carbohydrates, a considerable amount of protein, and several bioactive compounds like tannins and phytic acid (Lim et al., 2018). In the fruit processing industry, these unwanted parts of pink guava are often discarded as wastes without emphasizing the benefits of their reutilization.

230

Valorization of Fruit Processing By-products

Bioactive compounds and dietary fiber contents from the industrial by-products of guava have been incorporated into several food products with health benefits for humans (Cheok et al., 2016). High dietary fiber contents in the fruit have the capability to trap oil and water, hence these properties are useful in texture and viscosity modification of food products. Likewise, cereals that are normally used as dietary fiber in food products can be replaced with fruit byproducts, especially nutritious fruits like guava, since they have balanced soluble and insoluble dietary fiber content along with health-promoting antioxidants. Several experimental trials were successful in producing food products using by-products of guava, though not limited to pink-flesh guava. Guava peel flour was used as a partial replacement of wheat flour in cookies. Cookies with enriched dietary fiber and a satisfying sensory test result were obtained at 30% guava peel flour replacement (Bertagnolli et al., 2014). This study also proved an enhancement of antioxidants in the cookies. Guava seed flour was tested as a partial replacement for wheat flour in cupcakes and as a partial replacement for semolina in pasta (Hussein et al., 2011; Khalifa et al., 2016). Both the studies showed that guava seed flour was able to increase the dietary fiber content in the food products with acceptable sensory scores but there was a significant change in the color of the pasta. In addition, the guava seed flour was able to increase the phenolic content in cupcakes with reduced lipid oxidation, reduced growth of aerobic bacteria, and significantly lower mold and yeast growth after 8 days of storage as compared to those of the control. The seed and peel of guava, known as guava pomace, was tested against lipid peroxidation in frozen chicken meatballs and showed promising results for inhibition of lipid oxidation (Packer et al., 2015). Frozen chicken meatballs with guava pomace extract were kept for 3 months and were preferred by consumers against the normal frozen chicken meatballs. Guava pomace extract also showed significant antimicrobial activity against several food-related pathogenic microorganisms (Martin et al., 2012). This suggests that guava byproducts may be incorporated in food and beverages as a natural preservative. A few researchers have also reported pharmacological values of pink guava fruit and its by-products. In vitro studies on guava pulp extract have shown antimicrobial and free radical scavenging activities (Paz et al., 2015). Several health beneficial properties of different parts of pink guava and the potential bioactive compounds responsible for the properties are documented. Lycopene-rich extract from decanter by-product showed protective effect at 25 μg/mL against hydrogen peroxide-induced cytotoxicity in a human liver cell line (Kong et al., 2010c). Anticancer abilities of the acetone extract from the red-flesh guava pulp were observed on leukemia cells through induction of apoptosis based on an in vitro study (Bontempo et al., 2012). Hydroalcoholic peel extracts from pinkflesh guava also showed anticancer potential with inhibitory concentration values (IC50) of 27 mg/mL on HepG2 cell through 3-(4,5-dimethylthiazol-yl)-2,5-diphenyltetrazolim bromide assay (Garg et al., 2016). Qin et al. (2017) isolated meroterpenoids such as psiguajavadial A, psiguajavadial B, guajadial B, guajadial C, and guajadial F from pink-flesh guava. These meroterpenes exhibited cytotoxic effects on five human cancer cell lines: HCT116, CCRFCEM, DU145, Huh7, and A549. Another study which applied pink guava pomace extract on TNF-α-induced human umbilical vein endothelial cells demonstrated their inhibitory properties against the inflammatory process related to atherosclerosis (Kamarazaman et al., 2017). Preclinical studies using a rat model showed that polysaccharide extracts of pink-flesh guava fruit exerted an hepatoprotective effect (Alias et al., 2015). The dietary fiber contents have the tendency to trap bile acids and oil as well delay glucose diffusion in the digestive system once consumed. Therefore it is considered to have hypoglycemic and hypocholesterolemic effects by preventing the excessive cholesterol and glucose from being absorbed in the gastrointestinal tract, allowing them to be excreted through the bowels. To warrant the safety and therapeutic potential of guava on blood glucose and lipid profile, human clinical trials were performed and reported that both guava leaves and fruit were effective in reducing blood cholesterol and glucose levels (Kumari et al., 2016). Therefore the by-products of guava might well possess similar activities on humans due to the presence of similar bioactive compounds and dietary fibers. Reutilizing the fruit waste product for pharmacological purposes could attract the interest of many researchers and pharmaceutical institutions to develop possible research methods with profitable outcomes. Some examples of potential uses of guava industrial by-products are given in Table 11.1. Guava by-products that contain bioactivity could be functional in promoting human health. The bioavailability of polyphenols raises a debatable question in using them for medicinal purposes in the human diet. Drugs derived from natural products upon administration into human diet will undergo biotransformation in the liver. The possibilities are very high for the drugs especially pure isolated compounds to lose their structure, leading to the loss of their medicinal properties. This is a reason why most of the isolated bioactive compounds will never be able to be developed into commercial drugs. Natural product drug discovery is flourishing every year as hundreds or more plant-derived bioactive compounds are being reported (Alsarhan et al., 2014). These isolated bioactive compounds, either flavonoids or other types of polyphenols, mostly give positive results in the in vitro tests but later turn out to be ineffective upon pharmacokinetics testing in vivo (Androutsopoulos et al., 2010). Bioactive compounds from pink guava by-products will probably prevail in the

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231

TABLE 11.1 Potential use of guava industrial by-products with bioactivity. Guava by-products

Bioactivity

Potential use for humans

Peel

Hypolipidemic Antihyperglycemic Anticancer

G

Hypolipidemic Antihyperglycemic Antimicrobial

G

Hypolipidemic Antihyperglycemic Antiinflammatory Anticancer Antiulcer

G

Seed

Fruit/pomace

G

G

G G

Meal replacement in the form of flour/paste for diabetic and obese patients Additional mixture in health booster supplements Meal replacement in the form of flour/powder for diabetic and obese patients Natural antibacterial spray/powder Meal replacement in the form of flour/powder for diabetic and obese patients Additional mixture in health booster supplements Health drinks and supplements

bioavailability tests since they are commonly consumed by humans and the antioxidants will have a synergistic effect in providing essential health benefits.

11.3

Possible routes to upgrade pink guava by-products commercialization values

Katsuyama (1979) provided a guide in waste management for the food processing industries way back in the last century. The logical route to make use of food processing solid waste can be summarized as below: 1. 2. 3. 4. 5.

To produce high-value food by-products. Disposal (by sewer or landfilling) a zero-value-added waste (gives negative values). To use as part of animal feed. To use as biofuel (required chemical or biological conversion). To compost or for land application with limited soil amendment value (a low-value use).

In view of the amounts of valuable bioactive compounds that are present in pink guava by-products, most of the research has focused on extracting high-value food by-products such as lycopene and phenolic compounds or making use of dietary fiber functional properties that can be incorporated into selected foods. If pink guava by-products are to have added-value for further use, a few considerations have to be weighed up. The by-products contain high levels of moisture, ranging from 70% to 88% (Kong and Ismail, 2011; Nunes et al., 2016), and are susceptible to microbial spoilage and chemical deterioration if there are no treatments to reduce the water activity or the original microbial load. Thermal (such as moist heating or dry heating, microwave, infrared, and radiofrequency heating) or nonthermal (ultrasound, pulse electric fields, irradiation, and high hydrostatic pressure) technologies often affect some heat-labile phytochemicals present in food and vegetable wastes (Sagar et al., 2018). Some of these treatments also reduce the extraction yield (Galanakis, 2012). Pink-flesh guava fruit puree or juice has been subjected to different treatments to extend the shelf life. The quality attributes, such as the antioxidant capacities, lycopene content, and phenolic content of the end product, were measured to evaluate the optimum processing parameters in retaining or enhancing these quality attributes. Based on Table 11.2, it is evident that most drying, heat treatments, and osmotic dehydration (Del’Arco and de Sylos, 2018; Kong et al., 2010a; Nunes et al., 2016; Pino et al., 2008; Shishir et al., 2014) caused a significant reduction in volatile compounds, total phenolic and lycopene contents, and affected the color parameters (Shishir et al., 2014). The only exception was mild heat treatment at 90 C for 6 min which leads to increased levels of ascorbic acid, total carotenoids, total phenolics, total flavonoids, and enhanced antiradical 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity in guava pulp (Del’Arco and de Sylos, 2018). Nunes et al. (2016) suggested that oven drying at 55 C for 22 h decreased total phenolic content in guava fruit by up to 44% but the guava powders still contained levels of antioxidative compounds comparable with those of other tropical fruit powders. We suggest an innovative drying approach which is known as vacuum impregnation may be explored to minimize the loss of functional ingredients (Dehnad et al., 2016) in pink guava by-products.

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Valorization of Fruit Processing By-products

TABLE 11.2 Effects of different treatments on guava fruit, puree, and by-products. Sample type

Treatment parameters

Guava fruit (“Paluma” cv)

G

Guava pulp (“Paluma” cv)

G

G

G

G

Guava paste (“Paluma” cv)

G

G

G

Guava fruit (P. guajava L. Pedro Satovar.)

Guava puree (Beaumont var.) was mixed with distilled water and sugar

Ground Inactivation of enzymes (90 C for 6 min) Kept at 218 C

G

G G

G

G G

G

G G G G

Added sugar, pectin and citric acid Heat treatment: 70 C (35 min); 70 C
75 C (35 min); 100 C (15 min); and 80 C (15 min) in two subsequent concentration steps to reach 70
75 Brix Kept at 218 C

One-centimeter cubes were dehydrated in a G Freeze-dryer (FDG) at 250 C and 0.025 mbar for 48 h or G Forced air circulation oven (ODG) at 55 C for 22 h G Ground and sieved to a particle size of 20 mesh G Vacuum sealed and stored at 220 C

G

Guava by-products (decanter) Sungkai Beaumont var.

Homogenized, sterilized Kept at 218 C

Quality attributes measured

G G G G

Maltodextrin (MD) at 10%, 15%, and 20% (w/v) Homogenized Spray drying: feed flow rate of 350 mL/h pressure of 2.0 bars, drying air flow rate 50 m3/h at 25 C Inlet temperatures of 150 C, 160 C, and 170 C were studied, respectively

G

Dry using a convection oven Temperature (50 C
80 C) Drying time (4
6 h)

G

G G G G G G

G

G

Outcome

Del’Arco and de Sylos (2018)

Ascorbic acid content Total carotenoids Total phenolic Total flavonoid Antioxidant capacity (antiradical DPPH activity)

G

Moisture content Volatile compounds Phenolic profile Antioxidant capacity

Both drying processes promoted losses of G Some volatile compound (Z)-3-hexenyl acetate (k17.3% in FDG; k22.3% in ODG) G Total phenolic compounds (k39.5% for FDG; k44% for ODG) G Total antioxidant capacity k40 for ferric reducing antioxidant power (FRAP) G k58% for oxygen radical antioxidant capacity (ORAC)

Nunes et al. (2016)

Moisture content, Particle size, Powder yield, Bulk density, Tapped density Flowability Color

G

Drying at 150 C with 15% MD produced quality powder. For inlet temperatures up to 160 C, MD concentration affected the lightness (color) Condition of 10% MD at 150 C produced product with the highest a*/b*(0.369), lowest hue angle (69.7) and lowest chroma (23.3)

Shishir et al. (2014)

Lycopene content Lycopene-equivalent antioxidant capacity Lypophilic antioxidant activity (β-carotene bleaching assay)

G

Oven drying at 43.8 C for 6.4 h was the most efficient set of conditions Product with high lycopene content (14.78 compared to 17.21 mg/100 g in freezedried sample) and antioxidant capacity (21.34 mmol LE/100 g compared to 23.01 mmol LE/100 g in freeze-dried sample)

Kong et al. (2010a)

FDG, Freeze-dried guava; LE, lycopene equivalent; MD, maltodextrin; ODG, oven-dried guava. a*green/red; b*blue/yellow

G

G

G

G

Guava pulp: Ascorbic acidm15% Total carotenoidsm 59% Total phenolicsm8% Total flavonoidsm54.5% Antiradical DPPH activity m15% Guava paste: Ascorbic acidk42% Total carotenoidsk13% Total phenolicsk31% Total flavonoidsk6.5% Antiradical DPPH activityk25%

Reference

Pink guava Chapter | 11

11.3.1

233

Phytochemical extraction

There are four main groups of phytochemical research on pink guava fruits or their by-products: 1. polar phytochemicals, such as phenolic compounds, include flavonoids and anthocyanins (Chiari-Andre´o et al., 2017; Del’Arco and de Sylos, 2018; Flores et al., 2015; Killadi et al., 2018; Ribeiro da Silva et al., 2014; RojasGarbanzo et al., 2017; Vasco et al., 2008); 2. lipophilic phytochemicals, such as lycopene and carotenes (Del’Arco and de Sylos, 2018; Killadi et al., 2018; Kong and Ismail, 2011; Kong et al., 2010a,c; Rojas-Garbanzo et al., 2017); and 3. volatile compounds, such as (Z)-3-hexenal, 3-sulfanyl-1-hexanol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3sulfanylhexyl acetate, hexanal, and methional, which give rise to pink guava aroma (Nunes et al., 2016; Steinhaus et al., 2009); and 4. water-soluble polysaccharides with bioactivity (Alias et al., 2015; Kamarazaman et al., 2017). Table 11.3 lists the different solvent systems used in phytochemical extraction and the contents of total phenolics, total flavonoids, total carotenoids, and/or lycopene, along with the instrumental techniques used for analysis. Generally, sample to solvent ratio varying from 1:10 to 3:200 are applied while the type of extracting solvent depends on the target phytochemicals to be extracted. For polar phytochemicals, the common solvents are ethanol 50% followed by acetone 70% (Vasco et al., 2008); acetone 70% (Del’Arco and de Sylos, 2018); ethanol 70% (ChiariAndre´o et al., 2017); ethanol 80% (Nunes et al., 2016; Ribeiro da Silva et al., 2014); ethanol 85% containing hydrochloric acid (1.5 N) (Killadi et al., 2018); ethanol 80% containing 0.1% citric acid (Kong et al., 2010b); ethanol 95% (Thuaytong and Anprung, 2011); methanol 80% (Vishwasrao and Ananthanarayan, 2016); and methanol 70% containing 5% formic acid (Flores et al., 2015). For lipophilic phytochemicals, the common solvents are methanol:ethyl ether (1:1) (Del’Arco and de Sylos, 2018); acetone containing 0.05% butylated hydroxytoluene (BHT): ethanol 95%:hexane (Kong and Ismail, 2011) (1:1:2); acetone:hexane (2:3) (Ribeiro da Silva et al., 2014); acetone followed by petroleum ether (Killadi et al., 2018); and solely hexane (Vishwasrao and Ananthanarayan, 2016). Extra precaution is often practiced to prevent degradation of lightsensitive carotenoid and lycopene. The common procedure involves step-extraction by using solvents of different polarity, stirring, sonicating, or shaking continuously to ensure sufficient contact between the sample and solvent for efficient extraction. Prolonged extraction durations of up to 3 days (Chiari-Andre´o et al., 2017), slightly higher temperature up to 55 C (Kong et al., 2010b), and repeating the extraction with fresh solvent also improve the yield of the targeted phytochemicals. In fact Musa et al. (2011) applied different techniques and solvents on pink guava fruit and observed that pure solvent systems (acetone, ethanol, methanol, and water) were inefficient for antioxidant extraction. They recommended that solvents containing higher water concentrations and 50% acetone should be applied to extract phytochemicals from pink guava to achieve higher extraction yields of antioxidant compounds. High-performance liquid chromatography (HPLC) or spectrophotometric methods are the common techniques used to quantify total phenolic, flavonoids, carotenoid, and lycopene content. Of the two, HPLC offers qualitative identification of the individual phytochemicals in pink guava extracts. Kong et al. (2010c) explored supercritical carbon dioxide (SC-CO2, with 10% ethanol as the cosolvent) extraction on decanter by-products and found that SC-CO2 produced higher yields (3.15 mg/100 g dried sample) but lower lycopene content (13.66 mg/g extract) and antioxidant activity (in terms of lycopene-equivalent antioxidant capacity; and β-carotene bleaching activity) if compared with solvent extraction yields (0.68 mg/100 g dried sample) and lycopene content (49.82 mg/g extract). Therefore high phytochemical extract yields do not necessarily imply a similar trend for phytochemical content and activities. Castro-Vargas et al. (2010) attempted to apply supercritical fluid extraction with carbon dioxide and/or ethanol or ethyl acetate on guava seed. They observed that the use of 10% ethanol as a cosolvent enhanced the phenolic fraction yield from 0.39% to 1.18%. The highest yield of total extract and phenolic fraction was 19.033% and 1.738% (w/w), respectively, obtained from SC-CO2 ethanol extraction at 30 MPa and 40oC. Approximately 153 mg gallic acid/100 g sample was extracted with SC-CO2-ethanol at 10 MPa and 60 C. Bioactive polysaccharides were precipitated using ethanol 95% from aqueous extract (boiled in distilled water for 2 h) of pink guava pomace (Alias et al., 2015; Kamarazaman et al., 2017). These polysaccharides enhanced endogenous antioxidant activity in Sprague Dawley rats and able to attenuate paracetamol-induced liver injury (Alias et al., 2015). Although no identification of the polysaccharides was documented, we consider it as one of the important phytochemicals extractable from pink guava by-products. Similar extraction method applied on Rosa damascena, Calendula officinalis, and Matricaria chamomilla wastes yielded pectin and degraded pectin which are soluble in water

TABLE 11.3 Solvent extraction method, nonvolatile bioactive compounds from pink guava fruits, by-products, and instrumental technique used for measurement. Type of sample

Extraction method

Bioactive phytochemicals Total phenolic content (mg GAE/ 100 g)

Fruit pulp (freeze-dried)

G

G

G

1:40 S/L ratio (1:1 ethanol: water) 1 h 1:40 S/L ratio (7:3 acetone: water) 1 h Supernatant after centrifuge make up to 1% (w/v, solid sample in solvent) with distilled water

Frozen whole fruit, and fruit pulp of Guava “Paluma” cv

For total phenolics and total flavonoid: G 3:200 S/L ratio (70% acetone), vortex for 1 min For carotenoid G Sample was extracted with methanol:ethyl ether (1:1), vortex for 2 min, centrifuge G The process was repeated until the residue became colorless G Extracts were collected in a separator funnel with petroleum ether and ethyl ether G The absorbance of petroleum ether layer was recorded at 470 nm

Freeze-dried whole fruit, by-product of Sungkai Beaumont var.

G

G

G

G

3: 100 S/L ratio (solvent 1:1:2 acetone contains 0.05% BHT*:ethanol 95%: hexane) vortex for 1 min The mixture was shaken in an ice bath for 20 min 15% (v/v) deionized water was added and shaken for 5 min The absorbance of hexane layer was recorded at 503 nm after 5 min, to estimate the lycopene content

Total flavonoid content (mg rutin/100 g)

Lycopene content (mg/100 g)

Carotenoid content (mg lycopene/100 g)




462 (based on fresh weight basis, fwb)

Whole fruit: 1048
1463 (fwb)

Whole fruit: 125.2
187.4 (fwb)

Whole fruit: 6.64
8.86 (fwb)

Fruit pulp: 1033
1734 (fwb)

Fruit pulp: 185.5
260.6 (fwb)

Fruit pulp: 11.53
13.86 (fwb)

Whole fruit: 1.58 (fwb); 7.12 (dried weight basis, db) Decanter: 2.30 (fwb); 11.57 (db) Siever: 1.54 (fwb); 5.77 (db) Refiner: 1.29 (fwb); 3.94 (db)

Instrumental technique

Reference

Spectrophotometry

Vasco et al. (2008)

Spectrophotometry

Del’Arco and de Sylos (2018)

Spectrophotometry

Kong and Ismail (2011)

Oven-dried decanter byproduct of Sungkai Beaumont var.

G

G

G

G

G

G

Freeze-dried peels, pulps leftover and seeds

8.18
13.62 (db)

13: 400 S/L ratio (chilled solvent 1:1:2 acetone contains 0.05% BHT:ethanol 95%:hexane) vortex 1 min Solid consisted sample: MgCO3 at a ratio of 12:1 The mixture was mixed for 20 min with an orbital shaker; filter and reextracted twice The pooled filtrate was added with 16.7% (v/v) chilled deionized water and shaken for 5 min Phase separation to separate the hexane layer, which was passed through anhydrous sodium sulfate (Na2SO4); then concentrated at 35 C The resulted extract was diluted with dichloromethane prior to HPLC analysis

For total anthocyanins and total flavonoid: G 1:10 S/L ratio (solvent HCl (1.5 N) in ethanol (85%)), homogenized. G Extracted for 13 h under refrigeration in the dark G Filtered and absorbance was read at 535 nm (for anthocyanins) and 374 nm For lycopene and carotenoid content: G 1:10 S/L ratio (solvent 2:3 ratio of acetone:hexane) G Mixed for 1 min and filtered G Absorbance was recorded at 453, 505, 645 and 663 nm

Fruit pulp: 1723.06 (db)

Fruit pulp: nondetectable

Fruit pulp: 3.501 3 1022 (db)

Fruit pulp: 5.212 3 1022 (db)

Leftover and seeds: 1987.19 (db)

Leftover and seeds: 31.41 (db)

Leftover and seeds: 1.811 3 1022 (db)

Leftover and seeds: 2.667 3 1022 (db)

High-performance liquid chromatography (HPLC)

Kong et al. (2010a)

Spectrophotometry

Ribeiro da Silva et al. (2014)

(Continued )

TABLE 11.3 (Continued) Type of sample

Extraction method

Bioactive phytochemicals Total phenolic content (mg GAE/ 100 g)

Fresh paste of fruit pulp (Lalit) and peel

Fresh pulp of guava cultivar Samsi (P. guajava L.)

For anthocyanin content: G 1:10 S/L ratio (solvent, ethanoic hydrochloride) G Stored overnight in a refrigerator at 4 C G The extract was filtered and stored in the dark for color development and OD was read at 535 nm For lycopene content: G Fresh sample was dissolved in acetone solvent G Extraction was repeated in a mortar and pestle until the residue was colorless G The acetone extract was added with 10
15 mL petroleum ether in a separating funnel G The petroleum ether layer was collected and the OD was read at 473 nm G

G

G

G

G

1:50 S/L ratio (solvent ethanol 95%) Kept in darkness at 25 C for 4.5 h with continuous stirring at 100 rpm Filtering to remove the residue The filtrate would be evaporated by a rotary vacuum evaporator at 75 C The extract kept in brown bottle and stored in 215 C

163.36 (fwb)

Total flavonoid content (mg rutin/100 g)

Lycopene content (mg/100 g)

For peel (anthocyanin): 1.14 (fwb)

For peel: 0.47 (fwb)

For pulp: 0.45 (fwb)

For pulp: 0.34 (fwb)

35.85 (fwb)* mg catechin equivalent/100 g

Carotenoid content (mg lycopene/100 g)

Instrumental technique

Reference

Spectrophotometry

Killadi et al. (2018)

Spectrophometric

Thuaytong and Anprung (2011)

Freeze-dried and ovendried whole fruit of guava Pedro Satovar.

G

G G G

G

1:20 S/L ratio (solvent chilled ethanol 80%), extracted for 10 min Centrifuge at 10 C The residue was reextracted The combined supernatant was concentrated by using a rotary evaporator The extract was reconstituted in 10 mL water and stored at 220 C

82.2
146.6 (db)

63.3
78.4 (db)

Flavonols: myricetin, quercetin-3-orutinoside, quercetin

High-performance liquid chromatography (HPLC)

Nunes et al. (2016)

Spectrophotometry

Vishwasrao and Ananthanarayan (2016)

Spectrophotometry

Kong et al. (2010b)

Flavonone: naringenin Hydroxycinnamic acid derivative: 3hydroxycinnamic acid, 4-hydroxycinnamic acid, ferulic acid, rosmarinic acid Hydroxybenzoic acid derivative: 2hydroxybenzoic, 3,4-dihydroxybenzoic, benzoic acid, gallic acid, syringic acid Hydroxyphenylacetic acid derivative: 4hydroxyphenylacetic, 3,4dihydroxyphenylacetic acid

Fresh guava pulp Lalit var.

For lycopene content G Lycopene from pulp was extracted in hexane and absorbance of the extract was measured at 503 nm following the method of Kong and Ismail (2011) For total phenolics G 1:10 S/L (methanol 80%), sonicate in ice for 1 min G Centrifuged at 4 C for 15 min G Extraction was repeated twice G The supernatant was combined and made into a volume of 25 mL

Frozen guava cv Sungkai Beaumont refiner byproducts

G

G G

G G

1:10 S/L ratio (solvent ethanol 80% containing 0.1% citric acid) Extraction pH 2
6 Extraction temperature 40 C
60 C Extraction time 1
5 h Centrifuged at 4 C and the supernatant was collected for further analysis

114 (fwb)

133.58
265.0 (fwb)

69 (fwb)

184.46
344.99 (fwb)

(Continued )

TABLE 11.3 (Continued) Type of sample

Extraction method

Bioactive phytochemicals Total phenolic content (mg GAE/ 100 g)

Oven-dried milled whole fruit of Guava “Paluma” cv

G

G

G

G

Lyophilized peel, seed, flesh

G

G

G

G

G

G

G

Total flavonoid content (mg rutin/100 g)

Lycopene content (mg/100 g)

Carotenoid content (mg lycopene/100 g)

Instrumental technique

Reference

High-performance liquid chromatography (HPLC)

Chiari-Andre´o et al. (2017)

Rojas-Garbanzo et al. (2017)

Initial 1:6 S/L ratio (solvent ethanol 70%) sample and solvent in contact for 18 h Final 1:30 S/L ratio (solvent ethanol 70%) percolation process for 78 h Percolated at room temperature for 96 h The extract was filtered, concentrated under reduced pressure at 60 C, frozen, and freeze-dried and kept at 5 C

Flavonol: Kaempferol 3-O-xylosyl-rutinoside, quercetin 3-O-diglucoside and its derivatives 3O-acetilrhamnoside, 3-O-xylosyl-rutinoside, 3O-xyloside and 3-O-(6v-malonyl-glucoside)

1:10 S/L ratio (solvent aqueous methanol 90% containing 1% formic acid) Vortex mixed for 1 min, sonicated for 20 min Centrifuge for 5 min. The extraction was repeated twice The combined supernatant was filtered. Then methanol was removed with a stream of nitrogen The solution was partitioned against n-hexane for three times, then ethyl acetate for three times Both ethyl acetate fraction and the aqueous phase were dried The dried extracts were dissolved in 2.5 mL of methanol/bidistilled water (1:1, v/v) prior to analysis

Phenolic acid derivatives: galloyl-hexoside, gallic acid, galloyl-pentoside, hydroxybenzoylgalloylglucoside, dimethoxycinnamoyl-hexoside

Ultraperformance liquid chromatography (UPLC)

Flavones: chrysin-C-hexoside

Tandem mass spectrometry (MS/ MS)

Others: schottenol ferulate, 3methoxysinensetin, sesamolinol 40 -O-β-Dglucosyl (1-6)-O-β-D-glucoside, esculin, 3sinapoylquinic acid, (2)-epicatechin 8-Cgalactoside

Ellagitannins: valoneic acid bilactone, valoneaic acid bilactone Flavonols: quercetin-galloyl-hexoside, quercetinhexoside, quercetin-glucuronide, quercetinpentoside, quercetin-galloyl-pentoside, quercetindeoxyhexoside-hexoside, quercetin Monomeric flavanols: gallocatechin, epigallocatechin, catechin, epicatechin, gallocatechin gallate, epigallocatechin gallate, catechin gallate, epicatechin gallate Proanthocyanidins: proanthocyanidin Type B Dihydrochalcones: phloretin-C-glucoside (nothofagin), phloretin-O-glucoside (phlorizin) Stilbenes: piceatannol-O-glucoside (astringin) Acetophenones: myrciaphenone B Benzophenones: guavinoside A, guavin B, glucopyranosyl-benzophenone Anthocyanidins: cyanidin-3-O-glucoside Others: cinnamoyl-hexoside, abscisic acid, abscisic acid-hexoside

Freeze-dried fruit pulp of guava cultivars Homestead, Barbie Pink, Thai Maroon, Sardina 1, Sardina 2

G

G

G

G

1:20 S/L ratio (solvent aqueous methanol 70% containing formic acid 70:25:5) Extraction carried out for three times, at room temperature with a blender for 5 min for each extraction The combined extract was dried in vacuo Samples were dissolved in methanol before further analysis

Phenolic acid derivative: guavenoic acid, madecassic acid, asiatic acid, abscisic acid Anthocyanidin: cyanidin-3-O-glucoside, delphinidin 3-O-glucoside Flavonols: myricetin-3-O-β-D-glucoside, myricetin-3-O-arabinoside, myricetin-3-Oxyloside, quercetin-3-O-galactoside (hyperin). Quercetin-3-O-glucoside (isoquercitrin), quercetin-3-O-α-larabinoside (guaijaverin), quercetin, avicularin, isorhamnetin-3-Oglucoside, isorhamnetin-3-O-galactoside (cacticin) Monomeric flavanols: Gallocatechin-(4α-8)gallocatechol, gallocatechin-(4α-8)-catechin Others: turpinionosides A, pedunculoside, pinfaensin

BHT, Butylated hydroxytoluene; Fwb, fresh weight basis; Db, dried weight basis.

HPLC with photodiode-array detector HPLC-time of flightmass spectrometry

Flores et al. (2015)

240

Valorization of Fruit Processing By-products

(Slavov et al., 2016). Pectin originated from different plant sources (Marounek et al., 2007; Maxwell et al., 2012) exhibited comparable bioactivities as those of the antioxidative polysaccharides from pink guava pomace. Thus we assume the bioactive polysaccharides extracted from pink guava pomace are mainly pectin and degraded pectin. Microwave-assisted and ultrasonic-assisted extraction techniques, which show promising extraction efficiency on phytochemicals from fruit and vegetable wastes (Sagar et al., 2018), may be explored for the extraction of phytochemicals from pink guava by-products to maximize both the yield and the activities as well as improving the production cost-efficiency. Volatile compounds in pink guava fruit are evaluated using gas chromatography
mass spectrometry. Either headspace microsolid extraction (Nunes et al., 2016; Thuaytong and Anprung, 2011) or solvent extraction (Jorda´n et al., 2003; Steinhaus et al., 2009) were applied to capture volatile compounds from pink guava. Cyclohexane followed by methylene chloride (Jorda´n et al., 2003) or dichloromethane combined with sodium sulfate to successfully extract aldehyde, ketone, and esters, such as (Z)-3-hexenal, 3-sulfanyl-1-hexanol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3sulfanylhexyl acetate, and hexanal, which are the key aroma compounds in pink guava (Steinhaus et al., 2009). There is no research on volatile compounds from pink guava by-products to evaluate whether their inclusion in food or feed would contribute to the final products’ odor. Further investigation may be carried out to fill the knowledge gap. The main problem of phytochemical extraction is both the chemical solvents used and the leftover solid required additional operation and management costs beside the environmental issues. Therefore the search for technologies which could maximize the extraction yield with a minimum cost for pink guava by-products is required. Another approach in valorizing the guava by-products would be in vivo testing on the feed values through various feeding trials on different livestock. However, as per our previous discussion (Section 11.1), the low digestibility of guava fruit may limit the direct application of the by-products as an animal feed.

11.3.2

Prebiotics ingredients

Dietary fiber
rich fruit and vegetable wastes can be developed into prebiotic ingredients. Prebiotic ingredients are also known as nondigestible oligosaccharides which often exert health-promoting effects on the hosts upon consumption. They are acted upon by the gut microbiota to produce short-chain fatty acids associated with different effects on the host’s health and well-being. Several feeding trials have proved the positive effects of prebiotics in maintaining animal gut health through increasing the number of good bacteria and lessening the potential pathogen load (Gaggia et al., 2010). Fructooligosaccharides, inulin, and galactooligosaccharides are natural prebiotic ingredients extracted from Jerusalem artichokes, burdock, and chicory. Other oligosaccharides such as xylooligosaccharide, mannooligosaccaride, pectic oligosaccharides, and cellooligosaccharides, originating from some fruit and vegetables (Viera et al., 2017), also possess similar prebiotic effects (Go´mez et al., 2013; Yoo et al., 2012). Thus exploring the prebiotic potential in pink guava by-products is in line with the emerging application of prebiotic ingredients as a food or feed supplement. The depolymerization of lignocellulose fraction in plant biomass often improves digestibility (Sun et al., 2016) and causes changes in bioactivity because of reduced molecular weight and varied sugar residue composition (Wilcox et al., 2014). We found germination enhanced the prebiotic activity scores significantly in guava seed (Chang and Tan, 2016). Most of the prebiotic ingredients in pink guava by-products are water-extractable based on our recent study. High prebiotic activity scores of 34.1, 21.0, and 36.7 were observed for carbohydrate-rich extracts of freeze-dried refiner, siever, and decanter, respectively (Lim et al., 2018). However the prebiotic activity score dropped to 0.1, 0, and 0.26 after the by-products underwent water extraction at a solid to liquid ration of 1:30 at 55 C for 15 min (unpublished data). Our observation is in agreement with Go´mez et al. (2017) who have reviewed different water extraction techniques to obtain oligosaccharides with prebiotic properties from agroindustrial waste. Generally, the employment of water at high pressure and temperature (160 C
260 C) has been widely studied. Hemicelluloses depolymerization proceeded in different plant biomass such as corn cobs, orange peel, lemon peel waste, and sugar beet pulp to obtain prebiotics, such as xylooligosaccharides and glucooligosaccharides (Go´mez et al., 2013, 2014; Martı´nez et al., 2009; Moura et al., 2007). Extra refinery steps, such as discontinuous diafiltration followed by concentration, often yield higher amounts of prebiotic ingredients (Go´mez et al., 2013, 2014). These hydrothermal treatments involve high equipment costs which may not be feasible for industrial application. Subcritical water treatment at 250 C for 14 min has successfully extracted mannooligosaccaride at 28.3 g/100 g dry coconut meal without additional refinery steps (Khuwijitjaru et al., 2014). Sabajanes et al. (2012) reported a simple washing step on orange peel waste prior to a mixed cellulase-pectinase treatment produced about 31.3 kg oligosaccharides (glucooligosaccharide, arabinooligosaccharides, galactooligosaccharides, and oligogalacturonides) per 100 kg of enzymatic hydrolysis substrates. Further research on water extraction of pink guava byproducts to obtain prebiotic ingredients is warranted.

Pink guava Chapter | 11

11.3.3

241

Substrate for fermentation

The high carbon content in fruit and vegetable wastes allows its use as a substrate for fermentation by specific microorganisms to produce specific enzymes. The main constituents in fruit and vegetable wastes, such as cellulose, hemicellulose, pectin, help in the induction of cellulases, hemicellulases (xylanases and other associated enzymes), and pectinases through solid-state bioprocessing (Sharma et al., 2016). Feed enzyme inclusion in feed formula has been practiced to reduce feed costs since two decades ago. Current commercial feed enzymes include amylase, protease, phytase, pectinase, xylanase, and other cell wall-degrading enzymes that often improve the digestibility of protein, carbohydrate, and minerals in the feed (Beauchemin et al., 2003).

11.3.3.1 Microbial enzymes Commercial feed enzymes are mostly produced from fermentation by bacteria and fungi. Using fermentable fruit wastes to produce industrial enzymes has been studied extensively, but enzyme production through fermentation on pink guava waste is rarely studied. Moharib (2003) attempted to incorporate guava peel extract medium in a semicontinuous fermentation process to grow Saccharomyces cerevisiae 8112. They observed a maximum protease activity of 432 units after 60 h of fermentation. Fruit and vegetable wastes such as mango kernel, apple pomace, grape pomace, peel of pomegranate, citrus, pineapple, papaya, potato, and corn cob have been studied for their potential to produce enzymes through fermentation. Submerged fermentation by Fusarium solani NAIMMCC-F-2956 on mango kernel yields amylase activity of 0.89 U/mL (Kumar et al., 2013). Apple pomace is a common substrate to produce cellulase through solid-state fermentation, using Trichoderma sp. GIM 3.0010 (Sun et al., 2010) and Aspergillus niger NRRL 567 (Dhillon et al., 2012) yielded 3.9
7.6 U/gds (unit per gram of dried substrate) and 134.4
145.8 U/gds cellulase, respectively. Both fermentations showed a significant increase in cellulase activity when the medium contained additional lactose or other inducers. Ultrasonic treatment on mixed peel of pomegranate, orange, and pineapple has effectively raised the lipase about sixfold from submerged fermentation (Selvakumar and Sivashanmugam, 2017). Peptone-supplemented solid-state fermentation on orange peel with mutant Penicillium expansum CMI39671 produced higher lipase activity of 1870 U/gds (Qureshi et al., 2017). Corn cob supplemented with glucose, pepton, and Tween 80 after fermentation by Penicillium purpurogenum GE1 yielded a fourfold higher phytase activity of 170 U/gds (Awad et al., 2014). Similarly, boiled potato peels supplemented with (NH4)2SO4 and fermented with Aspergillus ficuum (ATCC 66876TM) produced 12.9 U/gds phytase, a 2.5-fold increment if compared with the controlled experiment (Tian and Yuan, 2016). Sterilized potato peel produced proteolytic enzymes of 400 U/gds after fermentation by Bacillus subtilis strain DM-04, a fourfold increase in enzyme activity, when the medium was supplemented with maltose and beef extract (Mukherjee et al., 2008). Potato peel waste fermented by Pleurotus ostreatus (Jacq.) Pleurotus kumm. (MCC16) produced lower proteolytic enzyme activity of 115 U/gds (Ergun and Urek, 2017). Submerged fermentation using A. niger on citrus waste peel and solid-state fermentation with Aspergillus tubingensis on papaya peel produced pectinase of 135 U/mL and pectin methylesterase of 246.8 U/gds (Ahmed et al., 2016; Patidar et al., 2016). Pepton supplementation raised pectinase activity (2817 U/gds) in mutant P. expansum CMI39671-fermented orange peel (Patidar et al., 2016). Fermentation on fruit and vegetable wastes yielded higher xylanase activities: Aspergillus awamori 2B.361 U2/1-fermented orange peel supplemented with nutrient solution, produced 43.7 U/gds/day of xylanase (Dı´az et al., 2012); while grape pomace 1 orange peel (1:1), after submerged fermentation with the same fungal strain, produced 98 U/mL/day of xylanase (Dı´az et al., 2012). Supplementation with a nitrogen source for solid-state fermentation often yields higher enzyme activities irrespective of the waste types and microorganism involved. Thus pink guava by-products supplemented by different nitrogen sources may be studied for its fermentability in producing desired industrial enzymes.

11.3.3.2 Single-cell proteins Fermentation of fruit and vegetable wastes also produces single-cell protein (SCP) (Yadav et al., 2016) that are dependent on the types of inducer and microorganism strain. The growing microorganisms often secrete hydrolases which hydrolyze the available polysaccharides for potential prebiotics derivatization (Samanta et al., 2012). Both SCP and the hydrolyzed carbohydrates could improve the feed values of the fermented fruit and vegetable wastes. SCPs are the dried cells of microorganism which can be used as protein supplements in animal feeds to alleviate food insecurity problem. The microorganism as a protein factory using agricultural by-products as raw material is one of the solutions to cope with the problem of worldwide protein shortage as a result of the global population expansion. The nonstarch polysaccharides constituents in fruits and vegetables provide a suitable physical structure to support a slow release of carbon sources for microbial community growth, which has made the agricultural wastes be a favorable

242

Valorization of Fruit Processing By-products

immobilization carrier. Guava pieces have been used to immobilized S. cerevisiae in repeated batch fermentation to produce wine from Indian cultivar grapes (Reddy et al., 2006). Higher stability of the yeast metabolism and an increase in fermentation rate, especially at low temperature indicates the great potential of guava fruit solid to be used as a immobilization carrier (Reddy et al., 2006) as well as a carbon source for enhancing protein content (Moharib, 2003). Yeasts such as Candida utilis, Cryptococcus aureus, and S. cerevisiae (Aruna et al., 2017; Gao et al., 2007; Gervasi et al., 2018; Mondal et al., 2012; Rahmat et al., 1995; Stabnikova et al., 2005; Villas-Boˆas et al., 2003) and fungi such as A. niger, Aspergillus flavus, Chaetomium spp., P. ostreatus, Neurospora sitophila, and Rhizopus oligosporus (Egwim, 2014; Khan et al., 2009; Rajesh et al., 2010; Shojaosadati et al., 1999; Villas-Boˆas et al., 2003; Yalemtesfa et al., 2010) were adopted for SCP production. Crude protein content of fruit and vegetable wastes has shown an increase from two- to fivefold through solid-state fermentation or submerged fermentation within a duration of 3
30 days. Protein enrichment is achievable through the manipulation of physical and chemical parameters of fruit and vegetable wastes fermentation conditions. For instance, a single supplementation of glucose can increase the protein content of yeast cells up to 60.31% (Mondal et al., 2012). In addition, the supplementation of (NH4)2SO4 also raised the crude protein content in the fermented substrate to 13.1%, 39.04%, and 14.8%, respectively (Aruna et al., 2017; Rahmat et al., 1995; Yalemtesfa et al., 2010). The high nucleic acid content of SCP was once a barrier to replacing the conventional protein sources, but the advances in biochemistry has made the production of food grade SCP possible (Yadav et al., 2016). However, the research on guava by-products for SCP production is scarce and warrants further investigation.

11.4

Processing method to minimize the waste after extraction

Guava wastes after puree production may be valorized as functional ingredients or additives in the food industries. These leftovers contained promising amounts of polyphenols, dietary fiber, hemicellulose, cellulose, and pectin (Mhd Abd Kader et al., 2016). Polyphenols, such as flavonoids, were reported to be as high as 39.36 mg quercetin/g extract in guava peels (Abdullah et al., 2012). Phenolic compounds, including epicatechin, quercetin, myricetin, isovanilic, and garlic acids, were identified in guava pomace extract—in total 13 phenolic compounds were reported (Denny et al., 2013). In fact the lycopene content in the decanter portion of pink guava is as high as 17 mg/100 g dry basis (Kong and Ismail, 2011). Guava is well known to be rich in dietary fiber. Jime´nez-Escrig et al. (2001) and Martı´nez et al. (2012) reported that guava by-products contain high dietary fiber (up to 69.1 g/100 g dry matter) and antioxidant activity up to 462 μmol/100 g dry matter, respectively. Polyphenols and dietary fiber may be recovered as food ingredients or supplements to enhance food products. Seed-free guava by-product contained approximately 32.86%
45.84% and 17.26%
25.04% cellulose and hemicellulose content, respectively, on a dry weight basis (Table 11.4). These water-insoluble fibers are a suitable feedstock for biofuel production. Although guava by-products possess economically beneficial properties, an effective processing strategy needs to be established for achieving sustainably production to gain the greatest economic advantages. Processing strategies such as mechanical and diffusional separation technologies, chemical and biochemical modifications may be feasible. Mechanical methods most of the time were applied for juice extraction stage to yield guava cake (peel, pulp and seeds), accounted approximately 25%
30% of the fruit. On the other hand, chemical and biochemical methods may be suitable for the nutritional recovery and downstream processing of guava waste. Generally, several approaches have been reported for guava waste recovery, which can be generalized into three categories: 1. Food ingredient and nutritional supplement: dietary fiber incorporated into fortified guava juice (Thongsombat et al., 2007), pectin as thickener, gelling agent, emulsifier, pharmaceutical additive, and prebiotic (Ranganna, 1986; Sriamornsak, 2003; Thakur et al., 1997). 2. Utilization of vegetable waste and fruit in generating biofuel: production of bioenergy (Singh et al., 2012) and biofuel (Gosavi et al., 2017) has been proposed. 3. Development of bioadsorbents for wastewater treatment: several studies were conducted on the effectiveness of guava seeds as biosorbents for removing heavy metals. These studies seem viable as downstream production strategy in guava juice industries. The resulting products may be rechanneled to mainstream production or other industries. Guava waste processed as food ingredient and directly applied to guava juice was reported by Thongsombat et al. (2007). Guava cake consists of peel, pulp, and seeds, yielded from juice extraction, and can be treated with sodium hexametaphosphate at 75 C to recover pectin. The filtrate recovered from the treated guava waste was then subjected to pectin precipitation using acidified ethanol. Finally, the precipitated pectin was collected, washed with ethanol, and

TABLE 11.4 Composition of pink guava fruit and its by-products. Sample

Ash

Sugar

Fat

Protein

Flavonoida

Lycopeneb

Pectin

Lignin

Cellulose

Hemicellulose

References

Whole fruit

4.1

3.51

No data

5.9

63.3
78.4

27.83

1.13
11.91

No data

No data

5.6

Adrian et al. (2012), Kamarazaman et al. (2017), Kong and Ismail (2011), Nunes et al. (2016), Patel et al. (2013)

Seed

1.01
1.18

6.23

10.12
13.93

7.71
11.19

83.97

8.74

0.58

22.06

63.94

14.35

Cock et al. (2013), Kong and Ismail (2011), UchoˆaThomaz et al. (2014), Wan Nur Zahidah et al. (2013)

By-products without seed

1.63
2.77

14.81
15.89

0.24
0.82

2.91
4.32

31.41

12.54
17.07

3.45
3.79

17.84
21.70

32.86
45.84

17.26
25.04

Mhd Abd Kader et al. (2016), Kong and Ismail (2011), Lim et al. (2018), Ribeiro da Silva et al. (2014)

Ash, sugar, fat, protein, pectin, lignin, cellulose, and hemicelluloses are in percentage (db). a Flavonoid content is expressed in mg catechin equivalent/100 g (db) or mg quercetin equivalent/100 g (db). b Lycopene content is expressed in mg/100 g (db).

244

Valorization of Fruit Processing By-products

recovered as crude pectin. The method successfully recovered approximately 30.50% crude pectin and 20.70% soluble dietary fiber, of which later 0.25% was used to fortify the guava juice. The improved guava juice formulation is believed to have greater economic value. Juices fortified with pectin recovered from guava cake have introduced an alternative way to enhance the value of guava waste. In addition, pectin as a heteropolysaccharide has been known to have diverse applications such as a thickening agent and stabilizer in beverages, a gelling agent for jam and jellies, dessert fillings, medicines, sweets, as well as a source of dietary fiber. The recovery of guava waste pectin demonstrates good opportunities due to its wide application and the recovery procedure does not require a sophisticated plant setup or skilled operators. Therefore it can be easily incorporated in the existing processing plant. In addition, solid residues after the pectin extraction maybe a promising feedstock for biofuel including bioethanol or biomethane production. Mhd Abd Kader et al. (2016) found that pink guava puree residue contained promising carbohydrate (11.82%
12.18%) and dietary fiber (18.63%
29.86%), and suggested pink guava by-products as suitable feedstocks in fermentation processes such as bioconversion and biofuel production. Two major biofuels, bioethanol and biogas, can be produced with agriculture-based feedstocks. The production of bioethanol or biogas have basically different approached, in which the feedstock compositions, processing workflows, parameters, plant setup, etc. have their own requirement. Generally, the production of bioethanol required acid or enzymatic hydrolysis of starch and cellulose into simple sugars (saccharification), followed by a fermentation process to produce ethanol and carbon dioxide (Jamai et al., 2007). Saccharification is a process converting starch into simple sugars (monosaccharides) using microorganism or enzymes such as glucoamylase and α-amylase (Shapouri et al., 2004). A pure culture, such as S. cerevisiae, is used for the fermentation process. Saccharomyces is commonly used in bioethanol fermentation due to the fact that it is able to tolerate up to 18% alcohol, 50% glucose, and 30% xylose (Gosavi et al., 2017). This is rather important as ethanol produced during the fermentation process would not inhibit the growth of the microorganism. However, Saccharomyces is unable to utilize pentose sugars, and therefore a sufficient amount of glucose released during the saccharification process is essential for successive bioethanol production. Processing steps for the bioconversion of guava waste to bioethanol are simple and only involve saccharification, fermentation, and distillation processes. Thus it is possible to integrate a bioethanol production plant to the existing construction layout of a guava processing plant. Another alternative for biofuel production is to generate biogas or biomethane from fruit waste. Biomethane production involves three major steps which are hydrolysis, acidogenesis, and methanogenesis. Each of these steps requires a series of microbial interactions, and produces a final product with varying composition that depends on the microbial population of each steps. Fruits are rich in moisture and organic matters may be utilized as a feedstock for an anaerobic digestion system (Bouallagui et al., 2003, 2005, 2009). Successful biogas production using waste relies on the pH, C/N ratio (carbon/nitrogen ratio), and inoculums. Kayhanian and Tchobanoglous (1992) suggested the suitable range of the C/N ratio for aerobic composting and anaerobic digestion is from 15 to 70 on a mass basis, which is particularly important in biogas production. Generally a digester is expected to operate in an optimal condition with a C/N ratio of 25
35. A higher C/N ratio might lead to lower gas production due to active consumption of nitrogen by methanogens. In contrast, a lower C/N ratio may allow ammonia accumulation and an increasing pH (pH . 8.5) that hinders methanogenic bacteria (Polprasert, 2007). An adequate C/N ratio of approximately 30 can be formulated with additional waste material which is high in carbon to waste with low nitrogen or vice versa. As observed by Mhd Abd Kader et al. (2016), the C/N ratio of pink guava is in favor of the refiner by-product (46:1); unfortunately the C/N ratio for siever (84:1) and decanter (115:1) by-products are beyond the range. Therefore the C/N ratio of guava waste can be improved to facilitate anaerobic digestion for biogas production. In addition, other factors such feedstock composition, pH, digestion temperature, and inoculums play an equal role in biogas production. Sitorus et al. (2013) attempted to produce biogas from mixed vegetable and fruit waste from traditional markets ( 6 78% vegetable waste, 6 4% tuber waste, and 6 18% fruit wastes). Approximately 160 kg of waste was fed into a 200 L single stage fed-batch anaerobic digester for biogas production within 14 weeks. The anaerobic digestion in the pH range of 5.3
6.8 and temperature of 28 C
46 C resulted in 65% methane with the biogas flow of 20
40 mL/min. Other than methane recovery, the remaining digested slurry can be used as biomanure. Although the reported method required optimization, the fermentation procedure and the reactor design have successfully produced methane as a useful energy source. Biogas yield decomposition of waste relies on the operating conditions; very close control of the feed composition and process environment is somewhat important. Another option for utilizing guava waste is to produce biosorbents for wastewater treatment. As mentioned, guava seeds contain promising amounts of cellulose, lignin, and protein, which are suitable for biosorbent preparations. Functional groups, such as amines, hydroxyl, carbonyl, carboxyl, and alkanes, on their surfaces are ideal for capturing anionic contaminants present in water. These functional groups are effective in fluoride sorption or capable of

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developing different types of interactions with metals (Cai et al., 2015). Several attempts were made by researchers to reveal the feasibility of guava waste, in particularly guava seeds, as a biosorbent for heavy metals and phenol removal. Abdelwahab et al. (2007) conducted a study with guava seed on Cr61 removal in aqueous solution. They concluded that maximum removal of about 100% Cr61 with initial concentration 25 mg/L was at pH 1 for adsorbent dose of 15 g/ L. Ramos-Vargas et al. (2018) introduced an aluminum-modified guava seed biosorbent to remove fluoride and arsenate in aqueous solution. In the study, a biosorbent was prepared using dried finely ground guava seed treated with 0.5 M hydrochloric acid at 70 C, followed by neutralization with 1 N sodium hydroxide solution. The guava seeds went through a reflux procedure with aluminum chloride (AlCl3) solution, and were subsequently dried at 60 C for 4 h. Finally, the recovered aluminum-modified guava seed biosorbent demonstrated fluoride and arsenate adsorption capacity of 0.3445 and 4 mg/g, respectively. On the other hand, Parate et al. (2016) investigated the nickel removal capacity of guava seed on aqueous solution. The guava seed adsorbent was prepared with heat treatment of 600 C for 1 h, subsequently incubated in an incubator shaker with 1 N potassium hydroxide solution at 200 rpm, 500 C for 4 h. The prepared adsorbent yield was approximately 45% on a dry weight basis. Using guava seeds in preparing activated carbon (AC) was reported by Amri et al. (2013) and Anisuzzaman et al. (2016). The prepared guava seed-AC successfully removed dyes and phenols in aqueous solution. Guava seed was dried and carbonized at 300 C for 1 h. Carbonized guava seed was then treated with zinc chloride (ZnCl2). The AC treated with ZnCl2 solution at the ratio of 3:1 (ZnCl2:AC) demonstrated high adsorption capacity on 2,4-dichlorophenol which was 20.9 mg/g. Guava seed used as biosorbent with or without chemical treatment exhibited a good outcome in removing heavy metals. Although the preparation procedure might require optimization for the processing parameters, as compared to other heavy metal removal methods and procedures it is a feasible source for biosorbents preparations in terms of economic aspects. However, posttreatment of the biosorbent utilized in heavy metal removal should be taken into considerations as well because it may be a source of pollution that causes hazards to the environment. Guava waste may be recovered into various useful applications. However, the recovery processing plant requires proper design, management, and maintenance. Banerjee et al. (2018) introduced an environment-friendly hydrothermal process in producing mango peel pectin. The process was further extended to recover specific polyphenols and sugars from the spent liquor. This processing flow may be adopted to design a waste recovery plant for guava. Hydrothermal methods with the aid of microwave eliminate the usage of reagents in extracting pectin. In this intergraded extraction strategy, water behaved as an acidic solvent that promoted the release of pectic substances from the biomatrix. This hybrid hydrothermal processing strategy claimed to be ecofriendly as the used acids are excluded, hence the costs involved in acid treatment and deacidification of effluents can be reduced. This method also demonstrated the biggest advantage in recovering most of the beneficial substances in the fruit. We propose an integrated refinery process flow (Fig. 11.2) on pink guava by-products in view of the data we have obtained about the useful components (Table 11.4). The seeds from pink guava are rich in protein, fat, flavonoids, lignin, cellulose, and hemicelluloses, but low in sugar and pectin content (Cock et al., 2013; Kong and Ismail, 2011; Uchoˆa-Thomaz et al., 2014; Wan Nur Zahidah et al., 2013). Seed-free by-products are rich in sugar (mainly fructose, sucrose, and glucose), pectin, hemicellulose, and lycopene (Mhd Abd Kader et al., 2016; Kong and Ismail, 2011; Lim et al., 2018; Patel et al., 2013; Ribeiro da Silva et al., 2014), but have low levels of protein and fat. Thus separate process flow targets for the seed and the seed-free by-products, respectively, may be more appropriate in extracting or producing the different useful and usable fractions. The seed-rich fraction may undergo protein isolation with alkaline at pH 11.5 followed by acid at pH 5 (Perez-Rocha et al., 2015). Ethanolic extraction could be applied on the residue to obtain liquor which is rich in sugar and phytochemicals and lignocellulose-rich residue for further utilization. The seed-free pink guava by-products which are rich in lycopene may be extracted with a microemulsion technique (Amiri-Rigi et al., 2016). Similarly, ethanolic extraction can be applied to the residue to isolate other high-value ingredients (Fig. 11.2). However, most existing guava processing establishments might need some modification and skilled plant operators to facilitate the processing approach. Initial capital investment for such facilities could be high, and a further assessment on the production yield to breakeven the investment is required.

11.5

Constraints and challenges in reutilizing pink guava by-products

Guava by-products as potential source for various value added products are beyond doubt. Various recovery strategies, downstream processing protocols have been intensively studied. However, effective utilization of food waste required several considerations as shown in Fig. 11.3 (Ghosh et al., 2016). To date various researches and results on recovering of guava by-products and its applications were reported in literatures. These results provided innovative ideas which

246

Valorization of Fruit Processing By-products

Seed-free guava waste Microemulsion technique to extract lycopene

Guava seed residue after protein isolation

Seed-free guava waste after lycopene extraction Water addition

Ethanol

Ethanol recycling

FIGURE 11.2 Proposed process flow for guava by-products valorization. Adapted from Banerjee, J., Singh, R., Vijayaraghavan, R., MacFarlane, D., Patti, A.F., Arora, A., 2018. A hydrocolloid based biorefinery approach to the valorisation of mango peel waste. Food Hydrocolloid. 77, 142a151.

Ethanol Pectin extraction

Conventional

Hydrothermal

Clear suspension Filtrated solids (cellulose, hemicellulose, lignin)

Pectin precipitation

Concentrated sugars and polyphenols

Alcoholic filtrate

Pectin

Distillation

Sugar + polyphenol + water

FIGURE 11.3 Important factors that need to be considered for successful utilization of a food wastebased product (Ghosh et al., 2016).

Governmental framework Legislation Health and safety standards Financial viability Assessment of waste sources Supply (pre postharvest)-and Wholesale retailer Food service provider Household

Public participation Education Attitude Ease of use Successful food waste utilization

Processing facilities Local facilities Operating cost Transportation

Utilization of waste products Public acceptance Communication campaign Education

Cost to process waste (cost vs benefit analysis)

maybe further developed into industrial scale production. Unfortunately, these research outcomes were mainly emphasized on laboratory scale, information for industrial scale applications were yet to be established. Data on scaling up and pilot plant operations were necessary in estimating economic feasibility in transforming waste to useful products. Technology transfer from research institutes to the industries required communication and cooperation from all aspects. Another important aspect to be considered is the volume of waste generated from the production plant; it must be identified before establishing the recovery plant (Godfray et al., 2010; Lundie and Peters, 2005). Continuous supply is essential to ensure the sustainability of the industry. In the case of guava waste, the physical and chemical features need to be understood in order to identify the type of products to be recovered, and their applications. The product yield should be sufficient to allow economic feasibility. Space availability in the plant and manpower for managing the plant

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setup should not be neglected. These factors are important in deciding whether it is worth investing in an on-site recovery plant or channeling by-products to the other downstream processing companies. In addition, the local authority may take initiatives in cultivating public awareness on food waste utilization and the benefits of waste recovery. Government and private sectors may work hand in hand to form a bridge between all stakeholders. Incentives such as grants or financial support for starting up waste recovery plants, together with tax relief for waste recovery projects will be effective in encouraging industrial stakeholders to participate. Government as the policy maker must set rules and standards for quality assurance in products produced with waste-recovered ingredients. The implementation and enforcement of rules should be monitored at all times. Products recovered from waste need to follow strictly the qualities and standards set by the government with regard to whether the recovered products are directly channeled to the consumers or used as a source of ingredients in food products. Especially guava waste, which requires proper storage conditions and other control aspects such as hygiene facilities inspection, and standard processing procedures, must be monitored to ensure the products are of high nutritional, microbiological, and sensory quality. Consumers’ acceptance of products derived from waste recovery is a key factor to consider as well. Consumers need to be educated concerning the importance of waste recovery, and this awareness will help to improve the acceptance of waste-recovered products.

11.6

Further research to fill the knowledge gap

Fruit and vegetable processing by-products have increased in recent years due to high global demand because of the human desire for healthy living. The desire for healthy living through the consumption of natural products has increased tremendously among the world population due to increasing medical expenses and ailments. Interest in the exploitation of medicinal and aromatic plants as herbal remedies, pharmaceuticals, perfumes and cosmetics, flavorings, and other natural products has greatly increased in recent years. As with many other commercial plants that are still being harvested from the wild and utilized by humans unsustainably, threats to species survival and genetic diversity have also increased in the case of medicinal plants as a result of overexploitation, habitat destruction, land use changes, and other stresses. Efforts regarding the conservation of natural plant resources, predominantly at the level of intraspecific genetic diversity, have not increased alongside developments in other areas, such as pharmacognosy and documentation of ethnobotanical uses. Therefore the reutilization of antioxidants from industrial by-products of fruits and vegetables is a potential way of preventing the loss of natural resources and potentially protecting several endangered medicinal plant species. Fruits like guava are being processed to fulfill the high demand but the by-products also need to be utilized. Although there are many research approaches have been conducted on the valorization of fruit by-products, the challenge resides in the practical implementation from the lab scale to the pilot scale and up to the commercialization of the outcome. The idea of valorizing fruit and vegetable by-products should be extended to various dimensions including consumable products, targeting both food and nonfood applications. Many fruit by-products with high contents of antioxidants and bioactive compounds are extensively utilized for nonconsumable products. This should be diversified to increase the valorization of industrial fruit and vegetable by-products into cost-effective health supplements with high antioxidant values. As an initial step, the preservation technology for fruit and vegetable waste should be developed, especially for fruits with high water content like guava. By-products from fruits like guava will be discarded at the initial stage, where almost 50% of the fruit is removed before further processing of the fruit flesh, and therefore the phytochemical and dietary fiber contents are mostly found in their natural state. In order to utilize the bioactive compounds and dietary fibers present in the by-product of this fruit, either in the peel, seed, or flesh, optimized technologies, such as effective drying, fermentation, or biopreservation, should be imposed to preserve the antioxidant contents. These technologies should also be cost-effective to be implemented into industrial targets. Effective waste management is not fully successful in most industries because of the high cost which overrides the easy disposal technique. Therefore optimization for the perfect technology to preserve the phytochemical and dietary fiber with minimal cost is necessary. Extraction techniques are crucial as ways to increase the yield of phytochemicals and dietary fibers in the desired product. The types of solvents used, nature of extraction, extraction time, temperature, and the targeted outcomes must be aligned to obtain the highest yield from the industrial by-products. Extraction yield mainly depends on the preservation and drying methods of the by-products since antioxidants can be easily denatured without proper preservation technology. Considering the environmental and economic values, agroindustrial by-products with high dietary fiber and antioxidant contents should be reutilized by promoting their sustainability and cost-effective preservation methods to bring value for the underutilized fruit and vegetable waste. Moreover, fruit wastes with high nutrient, antioxidant, and dietary fiber contents can be developed into functional foods and meal replacements for humans and also confined animals.

248

Valorization of Fruit Processing By-products

The fruit waste with high antioxidants and dietary fibers can also be pharmacologically developed for specified therapeutic effects. Human clinical trials on the products developed from fruit waste must be conducted upon preclinical trials to assure the therapeutic effectiveness and to increase general acceptance among the public.

References Abdelwahab, O., El Sikaily, A., Khaled, A., El Nemr, A., 2007. Mass-transfer processes of chromium(VI) adsorption onto guava seeds. Chem. Ecol. 23 (1), 73
85. Abdullah, N., Zulkifli, K.S., Abdullah, A., Aziman, N., Wan Kamarudin, W.S.S., 2012. Assessment on the antioxidant and antibacterial activities of selected fruit peels. Int. J. Chem. Tech. Res. 4, 1534
1542. Adrian, J.A.L., Arancon, N.Q., Mathews, B.W., Carpenter, J.R., 2012. Proximate analysis, in vitro organic matter digestibility, and energy contents of common guava (Psidium guajava L.) and yellow, strawberry guava (Psidium cattleianum Var. lucidum) tree parts and fruits as potential forage. J. Agric. Food Chem. 60 (42), 10398
10405. Ahmed, I., Zia, M.A., Hussain, M.A., Akram, Z., Naveed, M.T., Nowrouzi, A., 2016. Bioprocessing of citrus waste peel for induced pectinase production by Aspergillus niger; its purification and characterization. J. Radiat. Res. Appl. Sci. 9 (2), 148
154. Alias, A., Othman, F., Li, A.R., Kamaruddin, A., Yusof, R., Hussan, F., 2015. Supplementation of Psidium guajava (guava) fruit polysaccharide attenuates paracetamol-induced liver injury by enhancing the endogenous antioxidant activity. Sains Malays. 44 (8), 1129
1136. Alsarhan, A., Sultana, M., Khatib, A.A., Kadir, M.R.A., 2014. Review on some Malaysian traditional medicinal plants with therapeutic properties. J. Basic Appl. Sci. 10, 149
159. Amiri-Rigi, A., Abbasi, S., Scanlon, M.G., 2016. Enhanced lycopene extraction from tomato industrial waste using microemulsion technique: Optimization of enzymatic and ultrasound pre-treatments. Innov. Food Sci. Emerg. Technol. 35, 160
167. Amri, N., Alrozi, R., Osman, M.S., Nasuha, N., 2013. Optimization of pink guava (Psidium guajava) waste-based activated carbon preparation conditions for methylene blue dye removal. J. Mater. Chem. Eng 1 (1), 32
43. Androutsopoulos, V.P., Papakyriakou, A., Vourloumis, D., Tsatsakis, A.M., Spandidos, D.A., 2010. Dietary flavonoids in cancer therapy and prevention: substrates and inhibitors of cytochrome P450 CYP1 enzymes. Pharmacol. Ther. 126, 9
20. Anisuzzaman, S.M., Joseph, C.G., Krishnaiah, D., Bono, A., Suali, E., Abang, S., et al., 2016. Removal of chlorinated phenol from aqueous media by guava seed (Psidium guajava) tailored activated carbon. Water Resour. Ind. 16, 29
36. Aruna, T.E., Aworh, O.C., Raji, A.O., Olagunju, A.I., 2017. Protein enrichment of yam peels by fermentation with Saccharomyces cerevisiae (BY4743). Ann. Agric. Sci. 62 (1), 33
37. Awad, G.E.A., Helal, M.M.I., Danial, E.N., Esawy, M.A., 2014. Optimization of phytase production by Penicillium purpurogenum GE1 under solid state fermentation by using Box-Behnken design. Saudi J. Biol. Sci. 21 (1), 81
88. Banerjee, J., Singh, R., Vijayaraghavan, R., MacFarlane, D., Patti, A.F., Arora, A., 2018. A hydrocolloid based biorefinery approach to the valorisation of mango peel waste. Food Hydrocolloid. 77, 142
151. Beauchemin, K.A., Colombatto, D., Morgavi, D.P., Yang, W.Z., 2003. Use of exogenous fibrolytic enzymes to improve feed utilization by ruminants. J. Anim. Sci. 81 (E. Suppl. 2), E37
E47. Bertagnolli, S.M., Silveira, M.L., Fogac¸a, A.D., Umann, L., Penna, N.G., 2014. Bioactive compounds and acceptance of cookies made with guava peel flour. Food Sci. Technol. (Campinas) 34 (2), 303
308. Bontempo, P., Doto, A., Miceli, M., Mita, L., Benedetti, R., Nebbioso, A., et al., 2012. Psidium guajava L. anti-neoplastic effects: induction of apoptosis and cell differentiation. Cell Prolif. 45, 22
31. Bouallagui, H., Ben Cheikh, R., Marouani, L., Hamdi, M., 2003. Mesophilic biogas production from fruit and vegetable waste in tubular digester. Bioresour. Technol. 86 (1), 85
90. Bouallagui, H., Touhami, Y., Ben Cheikh, R., Hamdia, M., 2005. Bioreactor performance in anaerobic digestion of fruit and vegetable wastes. Process Biochem. 40, 989
995. Bouallagui, H., Lahdheb, H., Ben Romdan, E., Rachdi, B., Hamdi, M., 2009. Improvement of fruit and vegetable waste anaerobic digestion performance and stability with co-substrates addition. J. Environ. Manage. 90 (5), 1844
1849. Cai, H., Chen, G., Peng, C., Xu, L., Zhu, X., Zhang, Z., et al., 2015. Removal of fluoride from drinking water using tea waste loaded with Al/Fe oxides: a novel, safe and efficient biosorbent. Appl. Surf. Sci. 328, 34
44. Castro-Vargas, H.I., Rodriguez-Varela, L.I., Ferreira, S.R.S., Parado-Alfonso, F., 2010. Extraction of phenolic fraction from guava seeds (Psidium guajava L.) using supercritical carbon dioxide and co-solvents. J. Supercrit. Fluids 51, 319
324. Chang, Y.P., Tan, L.Y., 2016. Valorizing guava (Psidium guajava L.) seed: its prebiotic potential in comparison with winter wheat (Triticum aestivum L.) and red bean (Vigna angularis). In: Che Man, H. (Ed.), Proceedings International Conference on Agricultural and Food Engineering 2016 “Sustaining Agriculture, Preserving Life”, CAFEi 2016, Kuala Lumpur, Malaysia, August 23
25, 2016, pp. 192
197. Chang, Y.P., Sit, N.W., Anto Cordelia, T.A., 2017. Guava by-products: a source of functional carbohydrates, phytochemicals and enzymes. In: Murphy, A. (Ed.), Guava: Cultivation, Antioxidant Properties and Health Benefits. Nova Science Publishers, Inc, New York, pp. 17
50. Cheok, C.Y., Adzahan, N.M., Rahman, R.A., Abedin, N.H., Hussain, N., Sulaiman, R., et al., 2016. Current trends of tropical fruit waste utilization. Crit. Rev. Food Sci. Nutr. 58 (3), 335
361. Chiari-Andre´o, B.G., Trovatti, E., Marto, J., Almeida-Cincotto, G.J.D., Melero, A., Correˆa, M.A., et al., 2017. Guava: phytochemical composition of a potential source of antioxidants for cosmetic and/or dermatological applications. Braz. J. Pharm. Sci. 53 (2), e16141.

Pink guava Chapter | 11

249

Clery, R.A., Hammond, C.J., 2008. New sulfur components of pink guava fruit (Psidium guajava L.). J. Essent. Oil Res. 20 (4), 315
317. Cock, L.S., Ayala, J.D.M., Lopez, J.E.A., Schouben, A.L.G., 2013. Kinetics of alcoholic fermentation using guava (Psidium guajava) seed flour and dry mycelium of Aspergillus niger as nitrogen sources. DYNA 80, 113
121. Costa-Rodrigues, J., Pinho, O., Monteiro, P.R.R., 2018. Can lycopene be considered an effective protection against cardiovascular disease? Food Chem. 245, 1148
1153. Dehnad, D., Jafari, S.M., Afrasiabi, M., 2016. Influence of drying on functional properties of food biopolymers: from traditional to novel dehydration techniques. Trends Food Sci. Technol. 57, 116
131. Del’Arco, A.P.W.T., de Sylos, C.M., 2018. Effect of industrial processing for obtaining guava paste on the antioxidant compounds of guava (Psidium guajava L.) ‘Paluma’ cv. Rev. Bras. Fruitc. Jaboticabal 40 (2), e-011. Denny, C., Melo, P.S., Franchin, M., Massarioli, A.P., Bergamaschi, K.B., de Alencar, S.M., et al., 2013. Guava pomace: a new source of antiinflammatory and analgesic bioactives. BMC Complement. Altern. Med. 13, 235. Dhillon, G.S., Kaur, S., Brar, S.K., Verma, M., 2012. Potential of apple pomace as a solid substrate for fungal cellulase and hemicellulase bioproduction through solid-state fermentation. Ind. Crops Prod. 38, 6
13. Dı´az, A.B., deOry, I., Caro, I., Blandino, A., 2012. Enhance hydrolytic enzymes production by Aspergillus awamori on supplemented grape pomace. Food Bioprod. Process. 90 (1), 72
78. Egwim, E.C., 2014. Production of animal feed concentrates from soursop and pineapple peels using solid state fermentation. J. Biol. Agric. Healthc. 4 (22), 1
5. Available from: ,http://www.iiste.org/Journals/index.php/JBAH/article/viewFile/15737/16137.. Ergun, S.O., Urek, R.O., 2017. Production of ligninolytic enzymes by solid state fermentation using Pleurotus ostreatus. Ann. Agarian Sci. 15 (2), 273
277. Flores, G., Wu, S.-B., Negrin, A., Kenelly, E.J., 2015. Chemical composition and antioxidant activity of seven cultivars of guava (Psidium guajava) fruits. Food Chem. 170, 327
335. Fuller, S., Beck, E., Salman, H., Tapsell, L., 2016. New horizons for the study of dietary fiber and health: a review. Plant Foods Hum. Nutr. 71 (1), 1
12. Gaggia, F., Mattarelli, P., Biavati, B., 2010. Probiotics and prebiotics in animal feeding for safe food production. Int. J. Food Microbiol. 141 (Suppl. 1), S15
S28. Galanakis, C.M., 2012. Recovery of high added-value components from food wastes: conventional, emerging technologies and commercialized applications. Trends Food Sci. Technol. 26 (2), 68
87. Gao, L., Chi, Z., Sheng, J., Ni, X., Wang, L., 2007. Single-cell protein production from Jerusalem artichoke extract by a recently isolated marine yeast Cryptococcus aureus G7a and its nutritive analysis. Appl. Microbiol. Biotechnol. 77 (4), 825
832. Garg, M., Lata, K., Satija, S., 2016. Cytotoxic potential of few Indian fruit peels through 3-(4,5-dimethylthiazol-yl)-2,5-diphenyltetrazolim bromide assay on HepG2 Cells. Indian J. Pharmacol. 48 (1), 64
68. Gervasi, T., Pellizzeri, V., Calabrese, G., Di Bella, G., Cicero, N., Dugo, G., 2018. Production of single cell protein (SCP) from food and agricultural waste by using Saccharomyces cerevisiae. Nat. Prod. Res. 32 (6), 648
653. Ghosh, P.R., Fawcett, D., Sharma, S.B., Poinern, G.E.J., 2016. Progress towards sustainable utilisation and management of food wastes in the global economy. Int. J. Food Sci. . Available from: https://doi.org/10.1155/2016/3563478Article ID: 3563478. Gnanaraj, C., Shah, M.D., Song, T.T., Iqbal, M., 2017. Hepatoprotective mechanism of Lygodium microphyllum (Cav.) R. Br. through ultrastructural signaling prevention against carbon tetrachloride (CCl4)-mediated oxidative stress. Biomed. Pharmacother. 92, 1010
1022. Godfray, H.C., Beddington, J.R., Crute, I.R., Haddad, L., Lawrence, D., Muir, J.F., et al., 2010. Food security: the challenge of feeding 9 billion people. Science 327 (5967), 812
818. Go´mez, B., Gullo´n, B., Ya´n˜ez, R., Parajo´, J.C., Alonso, J.L., 2013. Pectic oligosaccharides from lemon peel wastes: production, purification, and chemical characterization. J. Agric. Food Chem. 61 (42), 10043
10053. Go´mez, B., Gullo´n, B., Remoroza, C., Schols, H.A., Parajo´, J.C., Alonso, J.L., 2014. Purification, characterization, and prebiotic properties of pectic oligosaccharides from orange peel wastes. J. Agric. Food Chem. 62 (40), 9769
9782. Go´mez, B., Mı´guez, B., Ya´n˜ez, R., Alonso, J.L., 2017. Extraction of oligosaccharides with prebiotic properties from agro-industrial wastes. In: Gonza´lez, H.D., Mun˜oz, M.J.G. (Eds.), Water Extraction of Bioactive Compounds: From Plants to Drug Development. Elsevier Inc, pp. 131
162. Gosavi, P., Chaudhary, Y., Durve-Gupta, A., 2017. Production of biofuel from fruits and vegetable wastes. Eur. J. Biotechol. Biosci. 5 (3), 69
73. Gutie´rrez, R.M.P., Mitchell, S., Solis, R.V., 2008. Psidium guajava: a review of its traditional uses, phytochemistry and pharmacology. J. Ethnopharmacol. 117, 1
27. Hussein, A.M., Kamil, M.M., Mohamed, G.F., 2011. Physicochemical and sensorial quality of semolina-defatted guava seeds flour composite pasta. J. Am. Sci. 7 (6), 623
629. Jamai, L., Ettayebi, K., Yamani, J.E., Ettayebi, M., 2007. Production of ethanol from starch by free and immobilized Candida tropicalis in the presence of α-amylase. Bioresour. Technol. 98 (14), 2765
2770. Jime´nez-Escrig, A., Rinco´n, M., Pulido, R., Saura-Calixto, F., 2001. Guava fruit (Psidium guajava L.) as a new source of antioxidant dietary fiber. J. Agic. Food. Chem. 49, 5489
5493. Jorda´n, M.J., Margarı´a, C.A., Shaw, P.E., Goodner, K.L., 2003. Volatile components and aroma active compounds in aqueous essence and fresh pink guava fruit puree (Psidium guajava L.) by GC-MS and multidimensional GC/GC-O. J. Agric. Food Chem. 51 (5), 1421
1426. Kadian, S.S., Garg, M., 2012. Pharmacological effects of carotenoids: a review. Int. J. Pharm. Sci. Res 3 (1), 42
48.

250

Valorization of Fruit Processing By-products

Kamarazaman, I.S., Abdul, R.L., Nik Hasan, M.K., Ahmad, M.R., Ayob, M.K.M., Rahim, N., et al., 2017. Antioxidant properties of polysaccharide extract from juice and pomace of Psidium guajava (pink guava) and its mitigating effect in early stage of atherogenesis. Nat. Prod. Chem. Res 5 (5), 270
275. Katsuyama, A.M., 1979. A Guide for Waste Management in the Food Processing Industry. The Processors Institute, Washington, DC. Available from: ,http://infohouse.p2ric.org/ref/31/30495.pdf.. Kayhanian, M., Tchobanoglous, G., 1992. Computation of C/N ratios for various organic fractions. BioCycle 33 (5), 58
60. Khalifa, I., Barakat, H., El-Mansy, H.A., Soliman, S.A., 2016. Influencing of guava processing residues incorporation on cupcake characterization. J. Nutr. Food Sci 6 (4), 1
8. Khan, M., Khan, S.S., Ahmed, Z., Tanveer, A., 2009. Production of fungal single cell protein using Rhizopus oligosporus grown on fruit wastes. Biol. Forum 1, 26
28. Available from: ,http://www.researchtrend.net/bfij/bf12/8_Mehnaaz.pdf.. Khuwijitjaru, P., Pokpong, A., Klinchongkon, K., Adachi, S., 2014. Production of oligosaccharides from coconut meal by subcritical water treatment. Int. J. Food Sci. Technol. 49 (8), 1946
1952. Killadi, B., Chaurasia, R., Shukla, D.K., 2018. Maturity indices and quality attributes during growth and development in guava cultivars ‘shweta’ and lalit’. J. Pharmacogn. Phytochem. 7 (2), 2102
2106. Kong, K.W., Ismail, A., 2011. Lycopene content and lipophilic antioxidant capacity of by-products from Psidium guajava fruits produced during puree production industry. Food Bioprod. Process. 89 (1), 53
61. Kong, K.W., Ismail, A., Tan, C.P., Rajab, N.F., 2010a. Optimization of oven drying conditions for lycopene content and lipophilic antioxidant capacity in a by-product of the pink guava puree industry using response surface methodology. LWT-Food Sci. Technol. 43 (5), 729
735. Kong, K.-W., Ismail, A.R., Tan, S.-T., Prasad, K.M.N., Ismail, A., 2010b. Response surface optimization for the extraction of phenolics and flavonoids from a pink guava puree industrial by-product. Int. J. Food Sci. Technol. 45 (8), 1739
1745. Kong, K.-W., Rajab, N.F., Prasad, K.N., Ismail, A., Markom, M., Tan, C.-P., 2010c. Lycopene-rich fractions derived from pink guava by-product and their potential activity towards hydrogen peroxide-induced cellular and DNA damage. Food Chem. 123 (4), 1142
1148. Kumar, D., Yadav, K.K., Muthukumar, M., Garg, N., 2013. Production and characterization of α-amylase from mango kernel by Fusarium solani NAIMCC-F-02956 using submerged fermentation. J. Environ. Biol. 34 (6), 1053
1058. Kumari, S., Rakavi, R., Mangaraj, M., 2016. Effect of guava in blood glucose and lipid profile in healthy human subjects: a randomized controlled study. J. Clin. Diagn. Res. 10 (9), BC04
BC07. Lim, S.Y., Tham, P.Y., Hilary Lim, Y.L., Heng, W.S., Chang, Y.P., 2018. Potential functional byproducts from guava pure´e processing. J. Food Sci. 83 (6), 1522
1532. Lundie, S., Peters, G.M., 2005. Life cycle assessment of food waste management options. J. Clean. Prod. 13 (3), 275
286. ˇ ´kova´, J., 2007. Effect of pectin and amidated pectin on cholesterol homeostasis and cecal metabolism in Marounek, M., Volek, Z., Synytsya, A., Coı rats fed a high-cholesterol diet. Physiol. Res. 56, 433
442. Martin, J.G.P., Porto, E., Correa, C.B., Alencar, S.M., Gloria, E.M., Cabral, I.S.R., et al., 2012. Antimicrobial potential and chemical composition of agro-industrial wastes. J. Nat. Prod. 5, 27
36. Martı´nez, M., Gullo´n, B., Schols, H.A., Alonso, J.L., Parajo´, J.C., 2009. Assessment of the production of oligomeric compounds from sugar beet pulp. Ind. Eng. Chem. Res. 48 (10), 4681
4687. ´ lvarez, J.A., Viuda-Martos, M., 2012. Chemical, technologies and in vitro antioxidant Martı´nez, R., Torres, P., Meneses, M.A., Figuero, J.G., Pe´rez-A properties of mango, guava, pineapple and passion fruit dietary fibre concentrate. Food Chem. 135, 1520
1526. Maxwell, E.G., Belshaw, N.J., Waldron, K.W., Morris, V.J., 2012. Pectin—an emerging new bioactive food polysaccharide. Trends Food Sci. Technol. 24, 64
73. Mercadante, A.Z., Steck, A., Pfander, H., 1999. Carotenoids from guava (Psidium guajava L.): isolation and structure elucidation. J. Agric. Food Chem. 47 (1), 145
151. Mhd Abd Kader, K.A., Ab Aziz, N., Aziz, A., Talib, A.T., Ahmad, N.H., Tan, C.P., et al., 2016. Evaluation on physico-chemical properties of pink guava puree residue as bioresource. Int. Food Res. J. 23 (Suppl.), S125
S131. Moharib, S.A., 2003. Utilization of guava peel waste as substrate for protein and protease production by Saccharomyces cerevisiae 8112. Adv. Food Sci 25 (2), 49
55. Mondal, A.K., Sengupta, S., Bhowal, J., Bhattacharya, D.K., 2012. Utilization of fruit wastes in producing single cell protein. Int. J. Sci. Environ. Technol. 1 (5), 430
438. Available from: ,http://www.ijset.net/journal/55.pdf.. Moura, P., Barata, R., Carvalheiro, F., Gı´rio, F., Loureiro-Dias, M.C., Esteves, M.P., 2007. In vitro fermentation of xylo-oligosaccharides from corn cobs autohydrolysis by Bifidobacterium and Lactobacillus strains. LWT-Food Sci. Technol. 40 (6), 963
972. M’Sadeq, S.A., Wu, S., Swick, R.A., Choct, M., 2015. Towards the control of necrotic enteritis in broiler chickens with in-feed antibiotics phasingout worldwide. Anim. Nutr. 1 (1), 1
11. Mukherjee, A.K., Adhikari, H., Rai, S.K., 2008. Production of alkaline protease by a thermophilic Bacillus subtilis under solid-state fermentation (SSF) condition using Imperata cylindrica grass and potato peel as low-cost medium: Characterization and application of enzyme in detergent formulation. Biochem. Eng. J. 39 (2), 353
361. Musa, K.H., Abdullah, A., Jusoh, K., Subramaniam, V., 2011. Antioxidant activity of pink-flesh guava (Psidium guajava L.): effect of extraction techniques and solvents. Food Anal. Methods 4 (1), 100
107. Najafi, A., Taheri, R.A., Mehdipour, M., Farnoosh, G., Martı´nez-Pastor, F., 2018. Lycopene-loaded nanoliposomes improve the performance of a modified Beltsville extender broiler breeder roosters. Anim. Reprod. Sci. 195, 168
175.

Pink guava Chapter | 11

251

Nunes, J.C., Lago, M.G., Castelo-Branco, V.N., Oliveira, F.R., Torres, A.G., Perrone, D., et al., 2016. Effect of drying method on volatile compounds, phenolic profile and antioxidant capacity of guava powders. Food Chem. 197, 881
890. Packer, V.G., Melo, P.S., Bergamaschi, K.B., Selani, M.M., Villanueva, N.D., Alencar, S.M., et al., 2015. Chemical characterization, antioxidant activity and application of beetroot and guava residue extracts on the preservation of cooked chicken meat. J. Food Sci. Technol. 52 (11), 7409
7416. Parate, V.R., Gulve, R., Labhane, U.C., Talib, M.I., 2016. Study of metal adsorbent prepared from guava seeds. IOSRJ Environ. Sci. Toxicol. Food Technol. 10 (9), 73
82. Patel, R.K., Maiti, C.S., Deka, B.C., Deshmukh, N.A., Nath, A., 2013. Changes in sugars, pectin and antioxidants of guava (Psidium guajava) fruits during fruit growth and maturity. Indian J. Agric. Sci. 83 (10), 1017
1021. Patidar, M.K., Nighojkar, S., Kumar, N., Nighojkar, A., 2016. Papaya peel valorization for production of acidic pectin methylesterase by Aspergillus tubingensis and its application for fruit juice clarification. Biocatal. Agric. Biotechnol. 6, 58
67. Paz, M., Gu´llon, P., Barroso, M.F., Carvalho, A.P., Domingues, V.F., Gomes, A.M., et al., 2015. Brazilian fruit pulps as functional foods and additives: evaluation of bioactive compounds. Food Chem. 172, 462
468. Perez-Rocha, K., Guemes-Vera, N., Bernardino-Nicanor, A., Gonzalez-Cruz, L., Hernandez-Uribe, J.P., Sanchez, A.T., 2015. Fortification of white bread with guava seed protein isolate. Pak. J. Nutr. 14 (11), 828
833. Pino, J.A., Panade´s, G., Fito, P., Chiralt, A., Ortega, A., 2008. Influence of osmotic dehydration on the volatile profile of guava fruits. J. Food Qual. 31 (3), 281
294. Polprasert, C., 2007. Biofuel production, Organic Waste Recycling Technology and Management, third ed. IWA Publishing, London, pp. 145
218. Pommer, C.V., Murakami, K.R.N., 2009. Breeding guava (Psidium guajava L. In: Jain, S.M., Priyadarshan, P.M. (Eds.), Breeding Plantation Tree Crops: Tropical Species. Springer, New York, pp. 83
120. Probst, Y.C., Guan, V.X., Kent, K., 2017. Dietary phytochemical intake from foods and health outcomes: a systematic review protocol and preliminary scoping. BMJ Open 7 (2), E013337. Qin, X.-J., Yu, Q., Yan, H., Khan, A., Feng, M.-Y., Li, P.-P., et al., 2017. Meroterpenoids with antitumor activities from guava (Psidium guajava). J. Agric. Food Chem. 65 (24), 4993
4999. Qureshi, A.S., Khushk, I., Naqvi, S.R., Simiar, A.A., Ali, C.H., Naqvi, M., et al., 2017. Fruit waste to energy through open fermentation. Energy Proced. 142, 904
909. Rahmat, H., Hodge, R.A., Manderson, G.J., Yu, P.L., 1995. Solid-substrate fermentation of Kloeckera apiculata and Candida utilis on apple pomace to produce an improved stock-feed. World J. Microbiol. Biotechnol. 11 (2), 168
170. Rajesh, N., Imelda-Joseph, Raj, R.P., 2010. Value addition of vegetable wastes by solid-state fermentation using Aspergillus niger for use in aquafeed industry. Waste Manage. 30 (11), 2223
2227. Ramos-Vargas, S., Alfaro-Cuevas-Villanueva, R., Huirache-Acun˜a, R., Corte´s-Martı´nez, R., 2018. Removal of fluoride and arsenate from aqueous solutions by aluminum-modified guava seeds. Appl. Sci. 8 (10), 1807. Ranganna, S., 1986. Pectin, In: Handbook of Analysis and Quality Control for Fruit and Vegetable Products, second ed. Tata Mc-Graw Hill Education, New Delhi, pp. 44
50. Reddy, L.V.A., Reddy, Y.H.K., Reddy, D.V.S., 2006. Wine production by guava piece immobilized yeast from Indian cultivar grapes and its volatile composition. Biotechnol. 5 (4), 449
454. Ribeiro da Silva, L.M., Teixeira de Figueiredo, E.A., Silva Ricardo, N.M., Pinto Vieira, I.G., Wilane de Figueiredo, R., Brasil, I.M., et al., 2014. Quantification of bioactive compounds in pulps and by-products of tropical fruits from Brazil. Food Chem. 143, 398
404. Rojas-Garbanzo, C., Zimmermann, B.F., Schulze-Kaysers, N., Schieber, A., 2017. Characterization of phenolic and other polar compounds in peel and flesh of pink guava (Psidium guajava L. cv ‘Criolla’) by ultra-high performance liquid chromatography with diode array and mass spectrometric detection. Food Res. Int. 100 (Pt 3), 445
453. Sabajanes, M.M., Ya´n˜ez, R., Alonso, J.L., Parajo´, J.C., 2012. Pectic oligosaccharides production from orange peel waste by enzymatic hydrolysis. Int. J. Food Sci. Technol. 47 (4), 747
754. Sagar, N.A., Pareek, S., Sharma, S., Yahia, E.M., Lobo, M.G., 2018. Fruit and vegetable waste: bioactive compounds, their extraction, and possible utilization. Compr. Rev. Food Sci. Food Saf. 17 (3), 512
531. Samanta, A.K., Jayapal, N., Kolte, A.P., Senani, S., Sridhar, M., Suresh, K.P., et al., 2012. Enzymatic production of xylooligosaccharides from alkali solubilized xylan of natural grass (Sehima nervosum). Bioresour. Technol. 112, 199
205. Selvakumar, P., Sivashanmugam, P., 2017. Optimization of lipase production from organic solid waste by anaerobic digestion and its application in biodiesel production. Fuel Process. Technol. 165, 1
8. Shapouri, H., Duffield, J.A., McAloon, A., Wang, M.Q., 2004. The 2001 Net Energy Balance of Corn-Ethanol. US Dept of Agriculture, Washington, DC. Available from: ,https://biomassboard.gov/pdfs/net_energy_balance_of_corn_ethanol_shapouri.pdf.. Sharma, R., Oberoi, H.S., Dhillon, G.S., 2016. Fruit and vegetable processing waste: renewable feed stocks for enzyme production. In: Dhillon, G.S., Kaur, S. (Eds.), Agro-Industrial Wastes as Feedstock for Enzyme Production Apply and Exploit the Emerging and Valuable Use Options of Waste Biomass. Elsevier Inc, pp. 23
59. Shishir, M.R.I., Taip, F.S., Aziz, N.A., Talib, R.A., 2014. Physical properties of spray-dried pink guava (Psidium guajava) powder. Agric. Agric. Sci. Procedia 2, 74
81. Shojaosadati, S.A., Faraidouni, R., Madadi-Nouei, A., Mohamadpour, I., 1999. Protein enrichment of lignocellulosic substrates by solid state fermentation using Neurospora sitophila. Resour. Conserv. Recycl. 27 (1
2), 73
87.

252

Valorization of Fruit Processing By-products

Sidhu, J.S., 2006. Tropical fruits: guava, lychee, papaya. In: Hui, Y.H. (Ed.), Handbook of Fruits and Fruit Processing. Blackwell Publishing, Ames, IA, pp. 594
634. Singh, A., Kulia, A., Adak, S., Bishai, M., Banerjee, R., 2012. Utilization of vegetable wastes for bioenergy generation. Agric. Res. 1 (3), 213
222. Sitorus, B., Sukandar, Panjaitan, S.D., 2013. Biogas recovery from anaerobic digestion process of mixed fruit-vegetable wastes. Energy Proced. 32, 176
182. Slavov, A., Panchev, I., Kovacheva, D., Vasileva, I., 2016. Physico-chemical characterization of water-soluble pectic extracts from Rosa damascena, Calendula officinalis and Matricaria chamomilla wastes. Food Hydrocolloid. 61, 469
476. Sriamornsak, P., 2003. Chemistry of pectin and its pharmaceutical uses: a review. Silpakorn Univ. J. Soc. Sci. Hum. Arts 3 (1
2), 206
228. Available from: ,https://doi.org/10.5458/jag.54.211.. Stabnikova, O., Wang, J.-Y., Ding, H.B., Tay, J.-H., 2005. Biotransformation of vegetable and fruit processing wastes into yeast biomass enriched with selenium. Bioresour. Technol. 96, 747
751. Steinhaus, M., Sinuco, D., Polster, J., Osorio, C., Schieberle, P., 2009. Characterization of the key aroma compounds in pink guava (Psidium guajava L.) by means of aroma re-engineering experiments and omission tests. J. Agic. Food Chem. 57 (7), 2882
2888. Sun, H., Ge, X., Hao, Z., Peng, M., 2010. Cellulase production by Trichoderma sp. on apple pomace under solid state fermentation. Afr. J. Biotechnol. 9 (2), 163
166. Available from: ,https://www.academicjournals.org/article/article1380799824_Sun%20et%20al.pdf.. Sun, S., Sun, S., Cao, X., 2016. The role of pretreatment in improving the enzymatic hydrolysis of lignocellulosic materials. Bioresour. Technol. 199, 49
58. Thakur, B.R., Singh, R.K., Handa, A.K., Rao, M.A., 1997. Chemistry and uses of pectin: a review. Crit. Rev. Food Sci. Nutr. 37 (1), 47
73. Thongsombat, W., Sirichote, A., Chanthachum, S., 2007. The production of guava juice fortified with dietary fiber. Songklanakarin J. Sci. Technol. 29 (Suppl. 1), 187
196. Thuaytong, W., Anprung, P., 2011. Bioactive compounds and prebiotic activity in Thailand-grown red and white guava fruit (Psidium guajava L.). Food Sci. Technol. Int. 17 (3), 205
208. Tian, M., Yuan, Q., 2016. Optimization of phytase production from potato waste using Aspergillus ficuum. 3 Biotech 6 (2), 256
263. Tridge, 2018. Guava global production and top producing countries. Available from: ,https://www.tridge.com/intelligences/guava/production.. Uchoˆa-Thomaz, A.M.A., Sousa, E.C., Carioca, J.O.B., Morais, S.M., Lima, A., Marins, C.G., et al., 2014. Chemical composition, fatty acid profile and bioactive compounds of guava seeds (Psidium guajava L.). Food Sci. Technol. Campinas 34, 485
492. Vasco, C., Ruales, J., Kamal-Eldin, A., 2008. Total phenolic compounds and antioxidant capacities of major fruits from Ecuador. Food Chem. 111 (4), 816
823. Vasconcelos, A.G., Amorim, A.D.G.N., dos Santos, R.C., Souza, J.M.T., de Souza, L.K.M., Arau´jo, T.D.S.L., et al., 2017. Lycopene rich extract from red guava (Psidium guajava L.) displays anti-inflammatory and antioxidant profile by reducing suggestive hallmarks of acute inflammatory response in mice. Food Res. Int. 99 (Pt 2), 959
968. Viera, A.D.S., Pedania, R., Albuquerque, M.A.C., Biscola, V., Saad, S.M.I., 2017. The impact of fruit and soybean by-products and amaranth on the growth of probiotic and starter microorganisms. Food Res. Int. 97, 356
363. Villas-Boˆas, S.G., Esposito, E., de Mendonc¸a, M.M., 2003. Bioconversion of apple pomace into a nutritionally enriched substrate by Candida utilis and Pleurotus ostreatus. World J. Microbiol. Biotechnol. 19 (5), 461
467. Vishwasrao, C., Ananthanarayan, L., 2016. Postharvest shelf-life extension of pink guavas (Psidium guajava L.) using HPMC-based edible surface coatings. J. Food Sci. Technol. 53 (4), 1966
1974. Wan Nur Zahidah, W.Z., Noriham, A., Zainon, M.M., 2013. Antioxidant and antimicrobial activities of pink guava leaves and seeds. J. Trop. Agric. Food Sci. 41 (1), 53
62. Weinert, I.A.G., van Wyk, P.J., 1988. Guava puree with reduced stone cell content: preparation and characteristics of concentrates and nectars. Int. J. Food Sci. Technol. 23 (5), 501
510. Wilberg, V.C., Rodriguez-Amaya, D.B., 1995. HPLC quantitation of major carotenoids of fresh and processed guava, mango and papaya. Lebensm.Wiss. Technol. 28 (5), 474
480. Wilcox, M.D., Brownlee, I.A., Richardson, J.C., Dettmar, P.W., Pearson, J.P., 2014. The modulation of pancreatic lipase activity by alginates. Food Chem. 146, 479
484. Yadav, J.S.S., Yan, S., Ajila, C.M., Bezawada, J., Tyagi, R.D., Surampalli, R.Y., 2016. Food-grade single-cell protein production, characterization and ultrafiltration recovery of residual fermented whey proteins from whey. Food Bioprod. Process. 99, 156
165. Yalemtesfa, B., Alemu, T., Santhanam, A., 2010. Solid substrate fermentation and conversion of orange waste into fungal biomass using Aspergillus niger KA-06 and Chaetomium spp KC-06. Afr. J. Micriobiol. Res. 4, 1275
1281. Available from: ,http://citeseerx.ist.psu.edu/viewdoc/download?doi 5 10.1.1.1013.8981&rep 5 rep1&type 5 pdf.. Yoo, H.-D., Kim, D., Paek, S.-H., Oh, S.-E., 2012. Plant cell wall polysaccharides as potential resources for the development of novel prebiotics. Biomol. Ther. 20 (4), 371
379.

Chapter 12

Pomegranate Shohreh Saffarzadeh-Matin Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran

Chapter Outline 12.1 Introduction 12.1.1 Polyphenol extraction of pomegranate waste 12.1.2 Assessment of extraction method efficiency 12.1.3 Purification and fractionation

12.1

253 254 265 268

12.1.4 Health benefits, safety assessment, and stability of pomegranate fruit extract 12.1.5 Concluding remarks References

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Introduction

Pomegranate (Punica granatum L.) fruit belongs to the botanical family of Punicaceae, which is natively cultivated in tropical and subtropical regions of the Middle East, such as Iran and India. This plant’s cultivation has been widespread throughout the Mediterranean countries, China, the United States, and Mexico. The edible and the nonedible parts of pomegranate comprise the seed, the arils as juicy outgrowths of the seed, the exocarp (the membrane), and the mesocarp (the peel), respectively. Interesting bioactive molecules and metabolites are distributed throughout various parts of this fruit, consisting of phenolics, proanthocyanidins, and flavonoids, which have made pomegranate a functional food of great interest for pharmaceutical, nutriological, and pharmacological research purposes over the centuries, from ancient cultures until now (Akhtar et al., 2015). According to International Trade Centre UNCTAD/WTO (ITC) statistics (Brinckmann, 2011), the total worldwide production of pomegranates is estimated to be around 3 million metric tons (MMT) annually. Iran, the United States, India, China, and Turkey have the largest areas of production (Ibrahim Kahramanoglu, 2016) and the Iranian contribution as a top producer is about 40% (above 0.75 MMT) of this production and roughly 0.35 MMT are processed into juice, jams, syrup, and sauce (Anonymous, 2009). Pomegranate fruits are mostly consumed in their fresh form and in processed forms as juice, jam, sauce, jellies, wine, and also as flavoring and coloring agents. Commercial pomegranate juice extracted from whole pomegranates has the highest antioxidant activities compared to other fruit juices, red wine, and green tea (Gil et al., 2000), which are mostly attributed to the presence of polyphenolic compounds. The predominant classes of polyphenols in pomegranate fruits are the nonanthocyanin phenolics, including the hydrolyzable tannins (HT) and flavonoids. HT include gallotannins, derivatives of gallic acid, and ellagitannins such as punicalagin A and B isomers (Adams et al., 2006), including gallagic acid (ellagic acid with 2 gallic acid moieties) and hexahydroxydiphenoyl-linked glucose that yields gallagic acid and/or punicalin upon hydrolysis. HT are considered as the most active antioxidants amongst the other groups of polyphenols in pomegranates. These are mainly located in the fruit peel, mesocarp, and aril (Fischer et al., 2011; Li et al., 2006). After commercial juicing of whole fruits, considerable amounts of these antioxidants still remain in the waste. The latter may be potentially used as alternative low -cost source of phenolic compounds (Ahmed et al., 2015; C¸am et al., 2014; Devatkal and Naveena, 2010). The resulting waste after squeezing juice from the fruit consists of approximately 73% peels and 27% seeds (Wang, 2011). According to research conducted on 20 Iranian pomegranate cultivars (Tehranifar et al., 2010), the edible portion (aril) of the fruit is about 38%
65% of the total fruit weight and consists of about 27%
47% juice and 53%
73%

Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00012-5 © 2020 Elsevier Inc. All rights reserved.

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seed. It has been reported that the antioxidant activity of pomegranate peel is relatively higher than seed and pulp in terms of scavenging capacity against superoxide anion, hydroxyl and peroxyl radicals, as well as for inhibiting CuSO4-induced low-density lipoprotein (LDL) oxidation (Pan et al., 2012; Li et al., 2006). An increasing demand for environmentally compatible production processes, coupled with rising operational and waste treatment costs, has led the food industries to focus on waste reduction to reduce costs and provide new sources of income. Therefore the implementation of new and advanced integrated waste preventive or recovery approaches for valuable natural by-products has become one of the most important objectives of the food and agricultural industries worldwide. In this regard the valorization of the pomegranate by-products may provide high-value antioxidant-rich health supplements instead of being used as cattle feed with low benefit or being directly disposed into landfill at a high cost and risk to environment.

12.1.1

Polyphenol extraction of pomegranate waste

Amongst the various natural components in pomegranate, the significance of antioxidants (also known as radical scavengers or antiradical compounds) in preventive medicine as well as their beneficial health effects is well known. Antioxidant properties are mostly attributed to the polyphenolic compounds, which are the most abundant secondary metabolites of plants. The antioxidant properties of phenolic compounds can preserve flavor and color while preventing vitamin destruction in foods (Ahmed et al., 2015; Devatkal and Naveena, 2010). Furthermore, they protect living systems from oxidative damage (Althunibat et al., 2010), protect cells from free radicals (Costantini et al., 2014), and prevent serious diseases (Al-Jarallah et al., 2013; Ammar et al., 2015; Anibal et al., 2013; Askari et al., 2014; Chrubasik-Hausmann et al., 2014). Since the synergistic action of polyphenolic compounds in pomegranate wastes has attracted much attention over the last 10 years, their extraction, purification, and bioavailability have been the subject of intensive research (Fischer et al., 2013; Saad et al., 2012; Safavi et al., 2014; Seeram et al., 2007). Maximizing the yield, avoiding any alterations, and maintaining the food grade nature of the target compounds during and after the recovery processing are among the ultimate goals of any applied technology for the recovery of valuable products from food and agricultural industrial wastes (Galanakis, 2012). Due to the high reactivity of natural polyphenols, the potential for polyphenolic profile alteration during the extraction process exists. Therefore an important challenge in any efficient extraction process is to concentrate the desired components with the preserved properties.

12.1.1.1 Important process conditions in solid
liquid extraction of polyphenols The important process parameters during the solid
solvent extraction of antioxidants from the pomegranate marc peel are the solvent polarity, solvent concentration and composition, temperature and time of extraction, solvent to dry waste ratio, and sample particle size. Based on the polarity of the solvent (defined by its dielectric constant) and its hydrogen bonding capabilities, the solubility of the various phenolic components with different chemical nature and their reactivity alter. Therefore depending on the target components the appropriate solvent or combination of solvents is selected and extraction is performed. The effect of the polarity efficiencies of the solvents on the polyphenol extraction from the pomegranate peel has been studied using organic solvents such as acetone (dielectric constant of 21), ethyl acetate (dielectric constant of 6), methanol (dielectric constant of 33), ethanol (dielectric constant of 24), and water (dielectric constant of 80) either alone or in combination at defined extraction conditions (Wang, 2011). Higher total extract yields were observed using water, acetone, ethanol, and methanol but the yield of target antioxidants was lower in comparison to ethyl acetate, which produced a higher purity of antioxidant. Lower yields of extracted antioxidants were attributed to a significant coextraction of concomitant substances. However, due to the economic and safety merits, a combination of ethanol and water is mostly considered as an environment-friendly solvent for producing food grade antioxidants from pomegranate industrial waste (PIW). On the other hand, hydroethanol is more effective in extracting phenolic compounds than alcohol or water alone (Markom et al., 2007). Contact time and temperature are among the other process conditions to be optimized. It is well accepted that increasing the temperature promotes extraction by enhancing the solubility of polyphenols and increasing the extraction coefficient. The equilibrium concentration has a linear relationship with the extraction temperature (Pinelo et al., 2005; Spigno et al., 2007). The solvent to dry waste ratio is affecting the concentration gradient between the particles of raw material and the solvent. The solvent to dry waste ratio efficiency on acquired polyphenolic extraction is consistent with mass transfer principles in which the concentration difference between the solid and the solvent dictates the driving force during mass transfer in the early stages, and then reaches equilibrium when most of the phenolics have been extracted out. The mass transfer is

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greater when a higher solvent to dry waste ratio is used (Cacace and Mazza, 2003; Pinelo et al., 2005), but it should be kept at an optimal amount due to economic and environmental issues. The significant contribution of the liquid to solid ratio and ethanol concentration variables has been reported in the recovery of the maximum levels of phenolics, flavonoids, and antioxidants from palm kernel by-products. Half factorial design was employed for this study, where pH, ethanol concentration, liquid to solid ratio, temperature, and time were considered as independent variables (Wong et al., 2015). As the extraction temperature increases the equilibrium ratio of solvent/solid decreases before reaching equilibrium, therefore extraction efficiency increases. However, increasing temperature may also decrease the polyphenolic extract purity by enhancing the possibility of simultaneous extraction of undesirable substances. Additionally, the possibility of polyphenols degradation increases at high temperatures (Qu et al., 2010). On the other hand in rising temperatures during the extraction process, the polymerization of low molecular phenolic compounds increases and upon a certain degree of polymerization, the reducing antioxidant power is decreased (Pinelo et al., 2004). This could probably be explained by the increased steric hindrance, which reduces the availability of the hydroxyl groups. As mentioned earlier, the high-reducing antioxidant activity of pomegranate husk extract is attributed to an appreciable amount of HT. They are highly polymerized and highly hydroxylated, therefore in rising temperatures during the extraction process, polymerization possibilities seem unlikely. For this reason, no significant changes in reducing antioxidant activities were observed in the temperatures between 35 C and 55 C (Shohreh Saffarzadeh-Matin and Khosrowshahi, 2017). Therefore extraction in mild conditions, that is, moderate time and temperature, has been mostly preferred. However, the exact monitoring of the polyphenols’ profile, for example, by high-performance liquid chromatography (HPLC)/ mass analysis, showed partial ellagitannins hydrolysis to produce low molecular weight ellagic acid (EA) derivatives during the extraction time (Saffarzadeh-Matin and Masoudi-Khosrowshahi, 2018). As a rule of thumb, extraction in higher temperatures (at shorter times) is only justified if the high-energy demand of the extraction is counterbalanced by a significant increase in yield, otherwise it must be avoided. Therefore reaction temperature optimization with regards to ratio of solvent/solid is also of paramount importance. Particle size is also an important extraction variable to be considered during the extraction process. Smaller particle size reduces the diffusion distance of the solute within the solid and increases the concentration gradient, which ultimately increases the extraction rate. Moreover, the extraction time is reduced as the path of the solute to reach the surface is reduced. Based on the above rationale, evaluation of the influence of extraction parameters (also known as process condition optimization) for each potential technology is of paramount importance. The latter provides a better understanding of the extraction processing and also effective utilization of natural waste.

12.1.1.2 Conventional extraction methods In general, solid
liquid conventional extraction includes an initial fast extraction of available solutes at the surface and a slow extraction from unruptured cells through a diffusion mechanism. Traditionally, conventional solid
liquid extraction methods such as Soxhlet and maceration extraction have been used to recover valuable compounds from pomegranate waste matrices. Some examples of conventional extraction of polyphenolic compounds from different parts of pomegranate wastes are presented in Table 12.1, in which the type of waste, the goal of extraction, the extraction method, the solvent used, whether process parameter optimization was performed, and the results of study are shown to give an overview of the objectives of studies and the results gained. In Table 12.1, mention of the numerical results such as extraction yields, total polyphenolic content (TPC), antioxidant percent, etc., has been avoided, because they mostly depend on the agroclimatic and environmental condition, stage of maturity, and the solvent and extraction technique used and are not reproducible. Although these techniques are static and intermittent processes, they suffer from the use of a high amount of solvent and a high extraction time and temperature, but still have been performed routinely by various research groups worldwide. Almost all of the extractions presented in Table 12.1 were performed at laboratory scale with no glimpse of their future commercial applications. One existing alternative for reducing energy consumption in conventional extraction whilst maintaining the stability of phenolic compounds is performing multistage countercurrent extraction (MSCE). In MSCE technology, improvements in heat and mass transfer and extraction efficiency is achieved through the combination of continuous countercurrent extraction with circulatory dynamic extraction (Wang et al., 2004). MSCE process provides a high recovery and an extract with a high soluble active ingredient concentration. Decreasing the processing time and solvent consumption as well as improvements in the final product quality and energy cost are among the other advantages of the MSCE process. These achievements have turned MSCE into a favorable extraction technology for application on a commercial scale (Xie et al., 2009). MSCE has been recently employed for extracting bioactive compounds from various herbal medicines (Wang et al., 2004; Lestari et al., 2010), for example, from Arachis hypogaea (Zhang et al., 2015; Yu et al., 2012; Bhornsmithikun et al., 2010).

TABLE 12.1 Conventional extraction of pomegranate waste. Waste source

Goal

Extraction method

Solvent

Optimization

Results

Reference

Peel

Antibacterial investigation

Maceration

Acetone, MeOH, H2O, EtOAc

NA

1—MeOH extract exhibited stronger radical scavenging effect than other 2—acetone extract showed the highest antibacterial activity, followed by MeOH and water extract

Unica et al. (2003)

Peel

Antimutagenicity investigation

Soxhlet

Acetone, MeOH, H2O, EtOAc

NA

Water extract exhibited stronger antimutagenicity, followed by acetone, EtOAc and methanol extracts

Negi and Jayaprakasha (2003)

Peel

Extraction of polyphenols and proanthocyanidin

Thermostatic water bath shaker

EtOH, 50% EtOH, EtOAc

OFAT

1—highest extract yield obtained by H2O, 50% EtOH and EtOAc 2—optimum parameters: 50 C and time: 20 min 3—proanthocyanidins recovery was better in a buffer at pH 3.5

Wissam and Abdelwahed (2012)

Peel

Extraction of the total phenolics, proanthocyanidin and flavonoids

Thermostatic water bath magnetically stirred

H2O, MeOH, EtOH, acetone, EtOAc

OFAT

1—optimum parameter: 40 C, solvent/ solid ratio of 15:1, extraction time of 240 min and particle size of 40 mesh 2—MeOH gave the highest extract yield followed by H2O, EtOH, acetone, EtOAc 3—EtOAc gave the highest TPC, proanthocyanidins and flavonoids

Wang (2011)

Husk (peel)

Extraction of TPC

Thermostatic water bath magnetically stirred

Hydroethanol and citric acid, liquid/solid waste: 40:1

RSM

1—EtOH concentration was only significant factor (97% of overall effect) 2—optimum condition: C EtOH 5 40%, pH 5 2 and t 5 1 h 3—optimal extract included punicalins A and B and ellagic acid, assessed by LC/MS

Amyrgialaki et al. (2014)

Industrial solid waste

Polyphenol extraction

Shaker incubator

Hydroethanol

RSM

The optimum operating conditions were an ethanol concentration of 60%, a solvent to dry waste ratio of 30 mL/g, the temperature of 46 C and the time of 6 h

Saffarzadeh-Matin and Khosrowshahi (2017)

Peel

Extraction process of tannins

Conventional maceration technique

Water, ethanol, and acetone

RSM

1—optimum conditions were found to be 62 min, 60 C, 1/8 g/mL, and 6 for extraction time, temperature, solid
liquid ratio, and pH, respectively 2—water provided better extraction results than ethanol and acetone 3—the maximum extract yield (50%) obtained from fresh pomegranate peel

Ben-Ali et al. (2018)

Peel

Polyphenol extraction

Solvent maceration

Hydroethanol

RSM

Optimal condition: solid to solvent ration of 1:30, temperature of 50 C and time of extraction of 45 min

Sood and Gupta (2015)

Peel

Pectin extraction

Thermostatic water bath magnetically stirred

Water (86 C, 80 min, 20 mM nitric acid), solid
liquid ratio: 1:50 g/mL

N.A.

Yielded between 6.8% and 10.1% lowmethylated pectins

Abid et al. (2017)

Peel

Tannin extraction as flocculant to remove M. aeruginosa cells

Water bath

Acetone aqueous solution

RSM

1—the optimal condition: 177 μm mesh size; 1:20 g/mL of solid
liquid ratio, 70% acetone aqueousSolution, 60 C for 3 h 2—removal yield of M. aeruginosa cells was 94.22%

Wang et al. (2018)

Peel

1—ellagitannin extraction 2—purification by Amberlite XAD-16 resin

Shaker incubator

Water

N.A.

1—yield: (58
60 g total pomegranate tannins/kg husk; time ,1 h) 2—analytical HPLC and tandem LC-ES/ MS, showed that it contains punicalagin (80%
85%, w/w) and ellagic acid (EA; 1.3%)

Seeram et al. (2005)

Leaves

Extraction and enrichment of TPC

Soxhlet, water bath temperature at 70 C, 40 min, and the solid/liquid ratio 1/10 (w/v)2—HPD100 macroporous resin to enrich

H2O, 50% MeOH, 50% EtOH and 50% acetone

RSM

1—hydroethanol showed the highest extraction yield and TPC 2—optimum conditions: the highest temperature (80 C), the longest extraction time (60. min) and 61% ethanol 3—TPC was enriched by HPD-100 macroporous resin

Wang et al. (2013)

Seed

Oil extraction and characterization

Shaker incubator at 60 C for 20 min then adding an additional chloroform for 3 min

Chloroform/ methanol solution (1/1, v/v)

N.A.

1—the pomegranate oil was a rich source of punicic acid, which represented more than 70% of the total fatty acids 2—PSO is a unique nutritional source of conjugated linolenic acids, tocopherol, sterol and squalene

Verardo et al. (2014), Durante et al. (2017)

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MSCE has also been conducted for the extraction of natural antioxidants from Iranian pomegranate industrial waste and extraction process conditions were also optimized (Saffarzadeh-Matin and Masoudi-Khosrowshahi, 2018). MSCE was carried out on the total 3.5 L custom-made MSCE equipment. An extraction flow and equipment schematic diagram is shown in Fig. 12.1. The instrument consisted of seven extraction units (EU1
EU7). Each unit had the same configuration and dimensions, consisting of a 500 mL double-walled jacket extraction pot with circulating heating water, including heater, pump, and transport pipe (8, 9, 10 respectively), a pump, and three valves (4, 5, 6). They were linked by circulating solvent pipes (7) of extracting solution; extract collector pipes (11), and fresh solvent pipes (3). Each EUs was operated in a closed loop configuration. MSCE in comparison with the single-pot extraction process has the advantages of considerable less solvent consumption (8 mL/g waste against 30 mL/g) and lower extraction temperature (40 C against 65 C) which led to improvements in the heat and mass transfer, the extraction efficiency, and energy cost under comparable conditions. However, lowering the particle size of the solid structure through initial grinding or cutting would intensify the conventional extraction process, but it has limited effects on the closed and unruptured cells existing inside the solid particles. Therefore researchers worldwide are progressively seeking nonconventional extraction methods to reduce the mass transfer resistance in the last slow step, leading to extraction process intensification.

12.1.1.3 Nonconventional extraction methods Nowadays, global awareness about the necessity of establishing a sustainable (circular) economy has encouraged food industries and food scientists to develop new greener and more efficient extraction processes. In this regard the new emerging technologies have been developed to maximize the extraction yield, increase extraction rate, and lower processing temperatures to advance the extraction of thermosensitive nutritional components. Additionally, maintaining the food grade nature of the target compounds during and after the recovery process has also been attempted by using generally recognize as safe solvents. In this regard, high-energy techniques to intensify extraction processes are gaining considerable interest. Studies conducted for polyphenol compounds extraction from pomegranate waste using unconventional methods are summarized in Table 12.2. FIGURE 12.1 Extraction flow and equipment schematic diagram (top) and MSCE apparatus (bottom); EU1
EU7: seven extraction units; (1) fresh solvent tank; (2) pump in line; (3) fresh solvent pipes; (4) fresh solvent valve; (5) extract valve; (6) circulating solvent valve; (7) circulating extract pipes; (8) bain-marie heated bath; (9) heating water pump; (10) heating water transport pipes; (11) extract collector pipes; (12) extract tank. Adapted with permission from Saffarzadeh-Matin, S., Masoudi-Khosrowshahi, F., 2018. Simultaneous separation and concentration of polyphenols from pomegranate industrial waste by multistage counter-current system; comparing with ultrafiltration concentration. Sep. Purif. Technol. 204, 261
275. https://doi.org/10.1016/j. seppur.2018.04.083, copyright (2018) Elsevier.

TABLE 12.2 Nonconventional extraction of pomegranate waste. Part of waste

Goal

Extraction method

Solvent

Optimization by

Results

Reference

Peel

Polyphenols extraction

Ultrasound-assisted extraction (UAE) (lab. scale)

Hydroethanol

RSM

Optimum condition: extraction time of 25 min, ethanol concentration of 59%, solid to solvent ratio of 1:44, and extraction temperature of 80 C

ˇ Zivkovi´ c et al. (2018)

Peel

Phenolic compounds

Pulsed UAE

Hydroethanol 70%, solvent/ solid: 10

RSM

1—optimum condition: intensity level of 105 W/cm2, duty cycle of 50% for 10 min 2—punicalagin and ellagic acid were the most predominant phenolic compounds

Kazemi et al. (2016)

Peel

Polyphenols extraction

UAE and enzymeassisted extraction

Water (solid to solvent ratio of 1:10)

RSM

Optimum conditions: ultrasonication time of 41.45 min, enzyme concentration of 1.32 mL/100 mL, incubation time and temperature of 1.82 h and 44.85 C

Nag and Sit (2018)

Peel

Polyphenol extraction

UAE

Hydroethanol

RSM

The optimal conditions: 70% hydroethanol, temperature of 60 C and extraction time of 30 min

Tabaraki et al. (2012)

Peel

Dietary fiber (DF) extraction, assessment of composition, antioxidant capacity, functional properties

Enzyme (α-amylase, protease, amyloglucosidase)assisted extraction

Water

N.A.

1—the total DF included cellulose, Klason lignin, uronic acid and neutral sugars (NS) 2—arabinose and xylose constituted $ 60% of total NS content 3—showed intermediate values for water- and oil-holding capacities 4—showed intermediate values for water- and oil-holding capacities

Hasnaoui et al. (2014)

Peel

Extraction of polysaccharides (lab scale)

Enzyme (pectinase)assisted extraction

Water

RSM

1—optimal condition: enzymolysis time 19.70 min, ratio of liquid to solid 20.5:1 (mL/g), dosage of enzyme 0.68% 2—the extract consisted of D-mannose, D-galactose and L-arabinose revealed by FT-IR and GC
MS 3—the extract exhibited strong reducing power and scavenging activities

Zhai et al. (2018)

(Continued )

TABLE 12.2 (Continued) Part of waste

Goal

Extraction method

Solvent

Optimization by

Results

Reference

Peel

Extraction of carotenoids to prepare oil enriched with antioxidant

UAE

Vegetable oils

RSM

Optimal condition: extraction temperature, 51.5 C; peels/solvent ratio, 0.10; amplitude level, 58.8%; solvent: sunflower oil

Goula et al. (2017)

Peel

Antioxidant extraction

Combination of UAE and pressurized liquid extraction

Water, hydroethanol

RSM

Optimal condition: water solvent, large particle size, 70 C, ultrasound power at 480 W and three cycles

Sumere et al. (2018)

Peel

Extraction of phenolics

UAE

Water

N.A.

1—ultrasound increased extraction yield and shortened the treatment time by over 20 times

Kaderides et al. (2015)

Peel

Extraction of polyphenols

Pressurized water extraction, MeOH extraction

Water




Pressurized water extraction was as effective as conventional methanol extraction for the recovery of polyphenols from pomegranate peels

C ¸ am et al. (2010)

Peel

Pectin extraction

UAE

Hot aqueous extractions

RSM

The optimal extraction condition: 1:17.52 g/mL of solid
liquid ratio, 1.27 of pH, 28.31 min of extraction time and 61.90 C of extraction temperature

Moorthy et al. (2015)

Peel

Extraction of polysaccharide

UAE

Water

RSM

1—optimal condition: ratio of solvent to solid waste 24 mL/g; 63 min; 55 C; and ultrasonic power, 148 W 2—the polysaccharide yield was 13.658

Zhu et al. (2015)

Peel

Polyphenol extraction

Microwave-assisted extraction

Water

RSM

1—optimal conditions: microwave output power 600 W, extraction time 60 s, and solid
liquid ratio 20 2—TPC: 210.36 6 2.85 mg GAE/g, DPPH IC50 of 14.53 μg/mL 3—a linear correlation (R2 5 0.9992) between concentration of the extract and reducing power was observed

Zheng et al. (2011)

Peel

Extraction of dye for wool and cotton dyeing

(UAE), enzyme (EAE), enzymemediated ultrasound-assisted extraction (EUAE)

Water, solvent to solid ratio of 10

OFAT

1—highest yield was obtained by EUAE followed by UAE, EAE 2—optimum conditions for UAE and EUAE: temperature 50 C, pH 10 and extraction time 40 min, for EAE: extraction time 80 min and temperature 60 C and 80 C at the same pH

Tiwari et al. (2010)

Peel

Extraction of dye

Microwave-assisted extraction (MAE), power of 330 W

50 mL of distilled water

RSM

Optimum conditions: extraction time 90 s, pH 3.5, amount of sample 1.48

Sinha et al. (2012)

Seeds

Oil extraction

Ultrasound-assisted aqueous enzymatic (cellulose and peclyve) extraction

Water

RSM

The optimum conditions: enzyme type, peclyve; extraction temperature 55 C; liquid/solid ratio, 6/1 mL/g; enzyme concentration 2% (w/w); extraction time, 2 h

Goula et al. (2018)

Seed

Extraction of seed oil

Superheated hexane extraction (SHHE), Soxhlet extraction and cold-pressing method were compared

Hexane

1—extraction temperature: 80 C, mean particle size: 0.25 mm, and flow rate: 1 mL/min, were selected 2—the SHHE showed a higher extraction efficiency (22.18 wt.%) within 2 h than Soxhlet extraction (17.94 wt.%) for 24 h and cold pressing (4.29 wt.%) for 72 h

Eikani et al. (2012)

Seeds

Polyphenols

Microwave heating method

EtOH

RSM

Solvent concentration was 40%, the ratio of material to liquid was 1:20 and the power was 400 W

Su et al. (2018)

Seed

Extraction of oil

1—high-pressure equipment 2—Soxhlet method

1—supercritical carbon dioxide 2—hexane

RSM

1—optimal condition: pressure 37.9 MPa, temperature 47.0 C and CO2 flow rate of 21.3 L/h 2—the content of total tocopherols was 14% higher in the oil extracted with supercritical CO2 than that obtained by Soxhlet extraction 3—minor difference was found in the fatty acid composition between two methods

Liu et al. (2009)

(Continued )

TABLE 12.2 (Continued) Part of waste

Goal

Extraction method

Solvent

Optimization by

Results

Reference

Seed

One pot recovery of high quality oil, food grade proteins and fibers (lab scale)

Enzyme (protease)assisted extraction at a concentration of 50 U/g for 14 h, at 45 C and pH 7.2

Water

N.A.

1—the protease-derived oil displayed 4% higher antioxidant activity, 2.3% higher content of conjugated fatty acids and 1.4 times higher total phenolic content than the hexane-extracted oil 2—the remaining waste residue was rich in insoluble fibers (97.6 g per 100 g WPS residue) 3—insoluble fiber had improved glucose absorption capacity and glucose dialysis retardation 4—the extracted free proteins were in protein hydrolysate form and had high values of the essential amino acid index (91.6%), protein efficiency ratio (5) and biological value (88.5)

Talekar et al. (2018)

Seed

Oil extraction

High-pressure equipment

Supercritical CO2

OFAT

1—extraction pressure was the dominant factor 2—higher pressure increased the oil yield and the contents of punicic acid, arachidic acid and gadoleic acid 3—at lower pressure or shorter extraction time, oil with high amount of total tocopherols was obtained

Liu et al. (2012)

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One of the advanced techniques to improve the efficiency of extraction is using pressurized solvents extraction, which works under high pressure and sometimes temperature. There are two pressurized solvent extraction methods, which are very popular for the extraction of polar target compounds, namely supercritical CO2 and subcritical water extraction, in which pressurized CO2 and water are used, respectively. The applied pressure usually ranges from 4 to 20 MPa, which ensures the maintenance of the solvent in the liquid state at the applied temperature. Carbon dioxide has low critical temperature and pressure of 31.1 C and 7.4 MPa respectively. It is also safe and food grade and available at low cost and high purity (Dı´az-Reinoso et al., 2006). For the extraction of polar polyphenols a cosolvent, for example, ethanol is often added to CO2 (Abbasi et al., 2008). Pressurized solvent extraction methods lead to an increase in diffusion rates, and better disruption of solute matrix bonds, which in turn leads to increases in the mass transfer and extraction rates. The supercritical CO2 method has been successfully used for oil extraction from pomegranate seeds (Liu et al., 2009). The scavenging ability of the extracted oil was correlated with the existed level of tocopherols (Liu et al., 2012). Subcritical water extraction of phenolic compounds from pomegranate seed residues was performed and the process parameters were optimized. The highest TPC of 4854.7 (mg/100 g DW) was obtained at a solid to water ratio of 1:40, while extraction time and temperature were 30 min and 220 C, respectively (He et al., 2012). Superheated hexane extraction and the cold-pressing method were compared for the extraction of pomegranate seed oil. Superheated hexane extraction had higher extraction efficiency while, the fatty acids profiles of extracted oils using both techniques was similar. The optimum extraction temperature, mean particle size, and flow rate were selected as 80 C, 0.25 mm, and 1 mL/min, respectively (Eikani et al., 2012). Other examples of high-pressure and temperature extraction methods are pressure-enhanced solid
liquid extraction (i.e., P 5 460 MPa) (Xi and Yan, 2017) or high hydrostatic pressure (P 5 600 MPa) (Pinela et al., 2017). Other techniques exist which may assist in the extraction of bioactive compounds. They could be applied as a preliminary step in the extraction of bioactive compounds in which, due to electrical field influence on the plant cell membrane, the plant cell permeability and accessibility toward the extraction solvent would be enhanced. In this regard, an instant controlled pressure drop (ICPD) process was used as an efficient way for texturing pomegranate peel to enhance the extraction yield of total phenols and antioxidants. During this pretreatment, the structure of pomegranate peel cells tissue expands and breaks to become more porous. The optimal operating conditions for ICPD were at 3 bar, 60 s, and 1 cycle. However little gain was obtained in comparison to untreated samples, TPC of 46.02 versus 38.77 mg GA/g dry basis and 2,2-diphenyl-1-picrylhydrazyl (DPPH%) antioxidant activity of 74.12% versus 62.10% (Ranjbar et al., 2016). High-voltage electrical discharge produced by applying pulsed rapid discharge voltages (usually from 20 to 80 kV/cm electric field intensity) was used as a nonthermal technique for the enhancement of the mass transfer of phenolic compounds from pomegranate peel in water. This process as a nonthermal preservation technique leads to the high-intensity UV light emission to generate intense shock waves and bubble cavitation, which trigger cell structure rupture, enhancing the release of intracellular components at ambient temperatures and shorter extraction times. The optimal conditions for this process were flow rate of materials 12 mL/min, electrodes gap distance 3.1 mm (corresponding to 29 kV/cm of electric field intensity), and liquid to solid ratio 35 mL/g. In comparison with the warm water maceration, the high-voltage electrical discharge method possessed higher efficiency for the extraction of phenolic compounds from pomegranate peel in water (Xi et al., 2017). High-voltage electrical discharges, pulsed electric fields, and ultrasound treatments were also applied as pretreatments and preliminary steps in the extraction of protein, total phenolics, and anthocyanins from blackberries. Due to the electrical field on the plant cells membrane, pore formation occurred which enhanced cell permeability (Barba et al., 2015). Ultrasound-assisted extraction uses high frequency sound waves (higher than 20 kHz), in which alternate cycles of expansion and contraction creates cavities or microbubbles in the liquid phase. Furthermore, due to the collapse of the cavitation bubbles, plant cell disintegration occurs, leading to the release of the target compounds. The latter would also lead to faster movement of molecules and higher penetration of the solvent into the target material, which is able to enhance the extraction of polyphenols from different plant by-products (Rosello´-Soto et al., 2015; He et al., 2016). The interaction of microwaves with polar molecules such as water to generate heat has triggered microwave-assisted extraction to enhance extraction efficiency. Microwaves are electromagnetic waves that are usually operated at a frequency of 2.45 GHz. On the other hand microwave energy can cleave and liberate the bound phenolics from the plant tissue, resulting in the increase of free TPC and the decrease of the bound phenolic content in the extracts and also a reduction of extraction time and higher extraction efficiency (Castro-Lo´pez et al., 2017; Zill-E-Huma et al., 2011;

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Boggia et al., 2016). Microwave energy has caused disruptions of vacuoles and the cell wall, increasing their accessibility to the extraction solvents, evidenced by the microscopic observations of extracted tissues (Zill-E-Huma et al., 2011). Enzyme-assisted extraction has also been performed by researchers for the disintegration of cell walls to facilitate the release of target compounds inside the cell. This is based on the rationale that the polysaccharides like cellulose, hemicellulose, and pectin in the plant cell walls prevent the release of intracellular substances. Therefore the degradation of cell wall polysaccharides using enzymes such as cellulase, β-glucosidase, xylanase, β-glucanase, and pectinase would certainly lead to the reduction of extraction time and higher extraction efficiency (Chen et al., 2011; Kapasakalidis et al., 2009). The effect of both ultrasound and viscozyme enzyme pretreatment for maximizing the yield of polyphenols extraction from pomegranate peel was studied and operation conditions including ultrasonication time, viscozyme concentration, incubation temperature, and time were optimized using response surface methodology (RSM) (Nag and Sit, 2018). These techniques, despite requiring advanced instrumentations and being high-energy-consuming procedures, were fast and efficient for the recovery of antioxidant compounds from pomegranate solid waste matrixes. However, so far their commercial application has been inefficient and somehow impossible. Accordingly, the considerable amount of published research in this area was performed on fresh fruits, which are manually peeled and extracted on a laboratory scale, with limited vision into their future industrial applications.

12.1.1.4 Extraction process optimization The main challenges considered for any technology to be applied on a commercial scale would be categorized as decreasing the processing time and improving the heat and mass transfer as well as improvements in the final product quality. In this regard, inspiring researchers are encouraged to optimize the critical parameters in any appropriate technology chosen for the recovery of value-added compounds from industrial wastes (Galanakis, 2013; Galanakis and Schieber, 2014). With reference to these criteria, the main objective of some studies conducted on the pomegranate waste valorizations was to identify the most suitable operating conditions for the extraction of phenolic compounds with preserved high antiradical and/or antioxidant activity. The conventional optimization techniques, such as the one-factor-at-a-time (OFAT) procedure, are not only time-consuming but also ignore the interactions of the variables. Therefore more reliable optimization techniques such as RSM have been adopted. In RSM a collection of statistical and mathematical techniques are used for the evaluation and quantization of the effects of several process parameters and their interactions on response variables. The main stages of the design of experiments in RSM consist of selecting a design space, or region of interest of independent (input) variables, modeling the dependent variables (output or responses) in terms of the selected variables, and finally optimization of the variables. Regions of interest were selected based on preliminary screening experiments or on the basis of the available literature on similar topics. In the case of solid
liquid extraction the main operating conditions (independent variables) considered in the literature are solvent polarity, solvent concentration and composition, temperature and time of extraction, solvent to dry waste ratio, and particle size. The dependent variables (the target responses) varied depending on the goal of the studies and were mostly based on calculations of extraction yield, TPC, total flavonoids (TFs), assessment of antioxidant/antiradical properties [DPPH%, ferric reducing antioxidant power (FRAP), etc.], and HT (gallotannins, ellagitannins). The efforts of most studies to find out the optimal settings of the process variables have been based on three variables using Box
Behnken or central composite design. These have been successfully used for developing, improving, and optimizing the extraction of phenolic compounds from a variety of natural products (Heydari Majd et al., 2014; Karacabey and Mazza, 2010; Liu et al., 2013). Once the design arrangements and experimental results of the extraction are known, the multiple regression coefficients are calculated using software (e.g., Minitab) for all responses. Regression analysis is performed and by applying the coefficients into the generalized model (Eq. 12.1), second-order polynomial equations for the acquired responses are obtained in terms of coded values of independent variables Y 5 β0 1

4 X i51

β i Xi 1

4 X i51

β ii Xi2 1

3 X 4 X

β ij Xi Xj

(12.1)

i51 j5i11

where Y is the predicted response variable, β 0 is defined as the constant, β i as the linear coefficient, β ii as the square coefficient, and β ij as the cross-product coefficient. Xi and Xj are two independent variables. The analysis of variance result is used to check the adequacy of the developed models and whether the models are significant and adequate at a 95% confidence level. The similarity between the experimental values and the predicted

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ones (using the models) for all response variables are another indication of satisfactory models. The three-dimensional and counterplot response surfaces of independent variables are obtained by keeping two of the variables constant. The constants were equal to the natural value of the zero level. To achieve the maximum level of all responses, the optimal level of extraction parameters is generated based on each response variable separately and in combination. Multiple graphical and numerical optimizations are run for determining the optimum level of the independent variables, with desirable response targets, and are further verified experimentally. The response surface models are verified by similarities between the observed and predicted values (Tables 12.1 and 12.2). In comparison with the large amount of research conducted on the laboratory scale, there are a limited number of reports on the green, feasible, and economic extraction of these compounds from the waste of fruit processing industries for commercial purposes (Amyrgialaki et al., 2014; Pan et al., 2012; Saffarzadeh-Matin and Khosrowshahi, 2017; Saffarzadeh-Matin and Masoudi-Khosrowshahi, 2018).

12.1.2

Assessment of extraction method efficiency

The main goal in the valorization of pomegranate waste has been maximizing the TPC of the extract with preserved antioxidant/antiradical properties. The assessment of various extraction method efficiencies has been mainly carried out by spectrophotometry and/or chromatography methods. Due to the synergistic and cooperative action of phenolic compounds, with regards to health benefits, evaluation of an integrated total antioxidant/antiradical value of an extract is preferred over the separation each (or a group of) phenolic compounds and the study of each individually, as is practiced in chromatographic analysis. Moreover, the latter is inefficient and costly, particularly in the optimization of process conditions. Therefore traditional spectrophotometric assays, have been widely used for the quantification of phenolic compounds in plant materials and extracts over the years. Moreover, high correlation has been already observed between the TPC of various parts of fresh pomegranate (peels, arils, juice, and mesocarp) as determined by Folin
Ciocalteu assays and the sum of the individual phenolic content determined by high-performance liquid chromatography-diode array detection-electrospray ion trap tandem. mass spectrometry (HPLC-DAD-ESI/MSn), reaching as high as R2 5 0.9995 (C¸am and Hi¸sil, 2010; Fischer et al., 2011).

12.1.2.1 Spectrophotometry assays The main goal in the valorization of pomegranate wastes has been maximizing the TPC of the extract, evaluated mostly by Folin
Ciocalteu assays, in terms of gallic acid and tannic acid equivalents and it has become a routine assay in studying phenolic antioxidants. The latter actually measures the reducing capacity of an extract, and therefore is nonspecific to phenolic compounds as reduction may be the result of many nonphenolic compounds (Kharchoufi et al., 2018), such as ascorbic acid, sugars, aromatic amines, organic acids, and Fe(II). Therefore the TPC value has been mostly considered as a mere preliminary selection parameter for producing a rough estimate of the extraction yield of polyphenols in various bioactive resources, and served for optimizing purposes within the same extracting solvent. The Folin
Ciocalteu reagent is typically made by first boiling the mixture of a specified amount of sodium tungstate (Na2WO4, 2H2O), sodium molybdate (Na2MoO4, 2H2O), concentrated hydrochloric acid, 85% phosphoric acid, and water. After boiling, a specified amount of lithium sulfate (Li2SO4, 4H2O) is added to the mixture to give an intense yellow solution. Upon addition of Folin
Ciocalteu reagent to the phenolic compounds under basic conditions (adjusted by a sodium carbonate solution to pHB10), dissociation of a phenolic proton happens, producing a phenolate anion, which is capable of reducing Folin
Ciocalteu reagent (FCR) through an electron transfer (ET) mechanism, leading to a blue color that is determined spectroscopically at 760 nm. The blue compounds formed between phenolate and FCR are independent of the structure of the phenolic compounds. This assay is convenient, simple, and reproducible. Among the polyphenols compounds in pomegranate waste extract, HT are the major group (about 50%), responsible mostly for antioxidant and antiradical properties as well as having health benefits. Moreover they constitute almost 50% of the total TPC. Therefore HT and TF, as major constituents of TPC, were also characterized and quantified spectroscopically and/or by LC/MASS analysis. Recently total phenolic, flavonoid, anthocyanin, and reports of HT in pomegranate peel from different geographical regions (about 40 countries) have been reviewed (Singh et al., 2018). However, the complexity of the phenolic constituents and the different reactivities of phenols toward assay reagents, has led to differing results (not reproducible even within the same cultivar at different times) in so many research studies conducted on various parts of pomegranate so far. This could be explained by the differences in the cultivar due to

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geographical location (agroclimatic and environmental condition), stage of maturity (Borochov-Neori et al., 2009; Mirdehghan and Rahemi, 2007), and the solvent and extraction technique used. Another important assay to evaluate extraction strategies and methods is antiradical and/or antioxidant activity assessment. Antioxidant capacity assays were classified into two main groups as “hydrogen atom transfer (HAT)” and “electron transfer (ET)” reaction-based analysis (Huang et al., 2005). According to this classification DPPH and FRAP methods are HAT- and ET-based assays, respectively. The HAT-based assays measure the capacity of a compound (or mixed polyphenols in crude natural extracts) to scavenge free radicals by hydrogen atom donation, and the ET-based assays measure its (or their) ability to reduce an oxidant compound (Huang et al., 2005). A FRAP reagent is prepared by mixing acetate buffer (300 mM, pH 3.6), 2,4,6-tripyridyl-s-triazine (10 mM in 40 mM HCl), and FeCl3  6H2O (20 mM) in the ratio of 10:1:1, respectively. The oxidant compound in FRAP assays is a colorless Fe31(TPDZ) complex which turns to a blue-colored Fe21(TPDZ) complex after the reaction with electron-donating antioxidants. The degree of color change is attributed quantitatively to the concentration of antioxidants. The hydrogen donating ability of phenolic compounds is directly correlated to the number and the availability of hydroxyl groups (Wang et al., 1999). The latter closely depends on both chemical structure and spatial conformation, which can alter the reactivity of the molecules. For example, oligomers show higher radical scavenging activity than corresponding monophenols because of their higher charge delocalization (Hagerman et al., 1998). The radical scavenging capacity of the extracts has been mostly assessed using the 2,2-DPPH and/or 2,20 -azinobis-(3-ethylbenz-thiazoline-6-sulfonic) diammonium salt (ABTS) radicals. This parameter is determined to elucidate the ability of the sample to reduce free radicals. When the free radical is scavenged through hydrogen donation, the color from the DPPH assay solution changes from dark purple to light yellow (Morelli and Prado, 2012). The decrease in the absorbance of the sample (S) tubes is correlated to the decrease in the absorbance of the control (C), resulting in an inhibition percentage of the free radical DPPH (DPPH%), which can be expressed through Eq. (12.2): I DPPH ð%Þ 5

ðC 2 SÞ 1 100 C

(12.2)

In the case of DPPH, the IC50 value has been also used to measure the antioxidant capacity. It is defined as the concentration of extract that is able to inhibit 50% of the initial DPPH radicals, expressed as mg/mL and calculated through the interpolation of linear regression analysis. The Trolox equivalent (TE) antioxidant capacity (TEAC) assay measures the antioxidant capacity of an extract, using ABTS radical anion scavenging activity as compared to the Trolox standards (calibration curve). In this assay a stable ABTS stock solution is first prepared by reacting ABTS with potassium persulfate in the dark overnight at room temperature. Upon adding the diluted ABTS solution to an extract or Trolox standard in methanol, the percentage inhibition of the blank absorbance at 734 nm is calculated and the results are expressed as micrograms of TE per gram of waste (Huang et al., 2005). In some of the references for the antioxidant activity assay superoxide anion radicals and/or hydroxyl radical scavenging assays in addition to DPPH or TEAC methods have been also evaluated (Ren et al., 2014). In intensive research conducted on polyphenols characterization in the extracts and juices from pomegranate peel, mesocarp, and arils, using a HPLC-DAD-ESI/MS method, antioxidant activities were also assessed by the TEAC, FRAP method, and a high correlation (R2 5 0.9995) of the TEAC and FRAP values was observed (Fischer et al., 2011). The main grounds for using various approaches simultaneously for antioxidant/antiradical evaluation has been the potential interference in various quantifying methods, stemming from the heterogeneity (different reactivity) and the complex nature of natural polyphenolic extracts, for example, pomegranate polyphenolic extracts (Singleton et al., 1999).

12.1.2.2 Chromatographic assays A detailed characterization of gallotannins and ellagitannins extracted from isolated arils and the entire pomegranate fruit with aqueous methanol (80%, v/v; 0.1% HCl) in an inert atmosphere of nitrogen was reported (Fischer et al., 2011). In this study an HPLC method for the characterization and quantification of individual phenolic compounds, especially tannins, were developed. Standard compounds of punicalagin and pedunculagin I were isolated and purified by preparative HPLC. HPLC eluents were directed toward mass spectrometry for detection. However, due to the large number of polyphenol compounds, for example, ellagitannins and isomers, complex chromatograms with many peaks were obtained from the crude extracts prepared by adopting the optimal process conditions in different studies. Because of this the solid-phase microextraction liquid chromatography and mass spectrometry (SPE/HPLC-DAD-ESI-MS) method has also been used for the fractionation, separation, and chemical structures assignments on a small-scale

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analysis. SPE as a cleaning up procedure was mostly performed prior to HPLC analysis, for example, on anthocyanin and nonanthocyanin phenolic compounds in various natural products (Hong and Wrolstad, 1990). In practice the methanolic extracts were evaporated to dryness and redissolved in acidified water (pH 3.0). The latter was directly used for anthocyanins characterization. Nonanthocyanin phenolics were extracted with ethyl acetate prior to fractionation via SPE cartridges according to systematic washing, equilibration, and elution steps. Two distinct fractions were obtained by elution with dilute acidic aqueous solution (hydrophilic phenolic) and ethyl acetate (hydrophobic ones), respectively. The eluates were used for LC analysis after some pretreatments. For anthocyanins the mobile phase consisted of 5% (v/v) formic acid in water (eluent A), and of water, formic acid, and methanol (10/10/80, v/v/v; eluent B). Through an optimized gradient program, elution was done and monitoring was performed at 520 nm. For nonanthocyanin phenolics, the mobile phase consisted of 2% (v/v) acetic acid in water (eluent A) and of 0.5% acetic acid in water and methanol (10/90, v/v; eluent B). After an optimized gradient program, simultaneous monitoring was performed at 280 and 320 nm. About 48 compounds were detected, including anthocyanins, gallotannins, ellagitannins, gallagyl esters, hydroxybenzoic acids, hydroxycinnamic acids, and dihydroflavonol, based on their UV spectra and fragmentation patterns. Individual phenolic compounds were quantified using calibration curves of the respective reference compounds (Fischer et al., 2011). An SPE setup using a C18 reversed phase SPE cartridge was also used for the separation and purification of nonanthocyanin phenolic compounds including HT and flavonoids from the polyphenolic extract produced from pomegranate industrial waste during conventional solid
liquid extraction (Saffarzadeh-Matin and Khosrowshahi, 2017) and MSCE (Saffarzadeh-Matin and Masoudi-Khosrowshahi, 2018). SPE protocols are shown in Fig. 12.2. Some of the typical HT with the highest concentrations in the hydroethanolic extract are presented in Fig. 12.3. The quantification of individual assigned phenolic compounds was performed by the preparation of different concentrations of correspondent

Conditioning of C18 reversed phase SPE cartridge with 3 mL MeOH

Equilibration with 10 mL H2O

10 mL sample loading

First elution with 10 mL H2O

Second elution with 10 mL 0.01% HCl

Combined eluted fractions and evaporation to dryness

Redissolution in 5 mL 2.0% AcOH

Membrane filtered 0.45 µm

LC-MS analysis FIGURE 12.2 SPE separation and purification protocol. Adapted with permission from Saffarzadeh-Matin, S., Masoudi-Khosrowshahi, F., 2018. Simultaneous separation and concentration of polyphenols from pomegranate industrial waste by multistage counter-current system; comparing with ultrafiltration concentration. Sep. Purif. Technol. 204, 261
275. https://doi.org/10.1016/j.seppur.2018.04.083, copyright (2018) Elsevier.

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FIGURE 12.3 Typical hydrolyzable tannins determined in PIW extract by LC/MS analysis: (1) ellagic acid; (2) ellagic acid-hexocide; (3) hexahydroxydiphenoyl-hexoside; (4) ellagic acid-deoxyhexocide; (5) ellagic acid-pentoside; (6) galloyl hexahydroxydiphenoyl-hexoside; and (7) hexahydroxydiphenoyl-gallagyl-hexoside (punicalagin). Adapted with permission from Saffarzadeh-Matin, S., Masoudi-Khosrowshahi, F., 2018. Simultaneous separation and concentration of polyphenols from pomegranate industrial waste by multistage counter-current system; comparing with ultrafiltration concentration. Sep. Purif. Technol. 204, 261
275. https://doi.org/10.1016/j.seppur.2018.04.083, copyright (2018) Elsevier.

reference compounds (e.g., gallic acid, EA, punicalagin) solutions for the preparation of calibration curves. Due to the commercial unavailability of some reference compounds, the calibration was prepared using a molecular weight correction factor for structurally related compounds (Fischer et al., 2011; Chandra et al., 2001).

12.1.3

Purification and fractionation

Apart from material pretreatment and extraction, the isolation and purification of the active ingredients are also among the necessary stages in the recovery of target compounds from natural wastes (Galanakis, 2013). Regarding the pomegranate industrial wastes, the necessity for further fractionation (also known as purification) of pomegranate extract for commercial purposes has been more or less neglected by researchers. Generally, only small-scale fractionation of HT, particularly ellagitannins as major constituents of TPC (about 50%), has been attempted for analysis and characterizations purposes based on spectrophotometric and/or chromatographic data.

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12.1.3.1 Preparative chromatography for isolation/purification process These purification methods involved solid-phase extractions with a variety of stationary phases and/or preparative HPLC, which are time-consuming and associated with labor-intensive practices and the use of large amounts of organic solvents (Russo et al., 2018; Fischer et al., 2011). Therefore they are not applicable for large-scale purification purposes. For example, for the isolation of punicalagin and pedunculagin I by preparative HPLC, powdered pomegranate peel was extracted with aqueous methanol (80%, v/v; 0.1% HCl), after flushing with nitrogen for a certain amount of time at ambient temperature and under continuous stirring. After filtration, the extract was evaporated to dryness in vacuo and the residue was dissolved in acidified water (pH 3.0). Separation was performed with a preparative C18 reversed phase column using an HPLC system. The mobile phase consisted of two eluents (A and B) using a programmed linear gradient at a constant flow rate in ambient temperature of 20 C. Total run time was 59 min, with retention times of 29 min for pedunculagin I and 40 min for punicalagin, and monitoring was performed at 280 nm. The collected fractions were evaporated to dryness, weighed, dissolved in a defined volume of methanol and identified by mass spectrometry. Isolated compounds were used for quantification purposes during an HPLC analysis of pomegranate extracts (calibration range 5
1000 mg/L).

12.1.3.2 Purification process through selective adsorption In the first report regarding rapid purification of ellagitannins, an aqueous pomegranate peel extract was adsorbed onto a vacuum-aspirated column of Amberlite XAD-16 resin, then the column was eluted with copious amounts of distilled water to remove all the sugary pale yellow eluate, and then the adsorbed tannins were eluted with MeOH. Methanol was removed in vacuo at low temperature (37 C) to yield a dark brown powder (58
60 g/kg husk) of pomegranate tannins. Using analytical HPLC and tandem LC-ES/MS, the latter contained mainly punicalagin (80%
85%, w/w), EA (1.3%, w/w), and unquantified amounts of punicalin and EA-glycosides. The XAD-16 column was regenerated by washing with water and could be reused over 100 times (Seeram et al., 2005). In a similar study with slight modifications, ellagitannins were isolated from fresh and fermented pomegranate peel using distilled water (solvent to solid ratio of 2, at 90 C), purified with Amberlite XAD-16 resin packed column, and converted into ellagitannin powder by vacuum drying (Kushwaha et al., 2015). About 38 g purified ellagitannin (78%
91.78% purity) powder was obtained from 1 kg fresh pomegranate peel.

12.1.3.3 Membrane filtration process Ultrafiltration (UF) is a flexible and mild pressure-driven process with a low energy requirement, which is based on the application of porous membranes with pore sizes of 0.01
0.1 μm (Saleh et al., 2006). The performance of the UF process has been previously investigated for purification/fractionation of polyphenolic extract from Eucalyptus bark (Pinto et al., 2017), grape seeds (Liu et al., 2011; Nawaz et al., 2006), winery effluents (Giacobbo et al., 2015), olive mill wastewater (El-Abbassi et al., 2009), pomegranate juice (Mirsaeedghazi et al., 2012), and the separation of phenolic compounds from sugar in apple juice (Wei et al., 2007). The main variables influencing the solute
membrane physicochemical interaction are membrane chemical structure and the molecular weight cutoff. Amongst various commercially available membranes, hollow fiber (HF) membrane modules have attracted special attention, since they are selfsupported, ensuring high surface to volume area and hold the option of back-flushing. These characteristics lead to space-savings, more productivity, and also a reduction in their maintenance costs (Simone et al., 2016). The application of UF HF membranes has been already reported for clarification and concentration of pomegranate juice (Cassano et al., 2011). A HF polysulfone (PS) membrane was employed for the concentration of the pomegranate industrial waste polyphenolic extract (Saffarzadeh-Matin and Masoudi-Khosrowshahi, 2018) due to PS membrane superior properties such as high material toughness, good stability at high temperature, compatibility with various solvents, applicable in wide pH range (pH 2
13), and low protein binding tendency (Ng et al., 2011). A UF experiment was performed in a cross-flow mode system—the equipment schematic and flow diagram is shown in Fig. 12.4. PS membrane (5) is a low-flux modular HF membrane with a nominal molecular weight cutoff value of 10 kDa, a maximum transmembrane pressure (TMP) of about 2 bar, and an active surface area of 1 m2. The feed and retentate flow rate were controlled by the speed controller of two variable speed peristaltic pumps (4) connected to a power supply (22.3 V and 0.22 A). The flow rates of feed and permeate were 600 and 10 mL/min, respectively. The retentate from the membrane was recycled back to the feed container (1) and the permeate was collected in a separate container (2). TMP was adjusted to 0.5 bar and controlled by the digital manometer (8). The volume reduction factor of 4 was set in the experiment under batch concentration mode.

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FIGURE 12.4 Schematic of ultrafiltration setup: (1) feed tank; (2) feed flow; (3) retentate flow; (4) peristaltic pump 1; (5) membrane; (6) permeated flow; (7) permeated solution; and (8) manometer. Adapted with permission from Saffarzadeh-Matin, S., Masoudi-Khosrowshahi, F., 2018. Simultaneous separation and concentration of polyphenols from pomegranate industrial waste by multistage counter-current system; comparing with ultrafiltration concentration. Sep. Purif. Technol. 204, 261
275. https://doi.org/10.1016/j.seppur.2018.04.083, copyright (2018) Elsevier.

A low-flux membrane has zero rejection (high permeability) toward the small size molecules such as sugar and salts (Liu et al., 2011), which have a negative impact on the performance of phenolic compounds. Prior to the filtration process, the membrane was soaked with ultrapure water overnight to remove any contamination and a membrane compaction step was carried out at a slightly greater than operating pressure in order to enhance the permeate flux and membrane permeability (Persson et al., 1995). After the UF concentration process, the total phenolic content, the DPPH radical scavenging capacity, and the FRAP-reducing antioxidant power were increased approximately by two times compared to the initial feed. The separation ability of a membrane can be established in terms of solute rejection (Rj%), defined Eq. (12.3), where the Cp and Cf are the permeate and the feed concentrations, respectively.   Cp Rj 5 1 2 3 100 (12.3) Cf Putting the amount of the total phenolic in the permeate and the feed samples into Eq. (12.3), the rejection percent (Rj%) of membrane of 73.73% was achieved for the TPC. This Rj% is more than previously reported for the UF concentration of pomegranate juice using modified poly(ether ether ketone) HF membrane (44.5%), operated at much higher TMP (0.96 bar) and feed flow rate (1166 mL/min) (Cassano et al., 2011). It was also more than Rj% reported during the UF clarification of pomegranate juice using mineral CARBOSEP M2 membrane (45.45%), operated at a TMP of 2 bar and a flow rate of about 2 L/min (Baklouti et al., 2012). Also this TPC rejection is more than that reported for the concentration of grape pomace with GE2540, DL2540, Nanomax 95, and Nanomax 50 membranes (20%
60%) and approximately similar to that reported for ceramic membrane at the highest TMP (about 80%) (Dı´az-Reinoso et al., 2009). Microfiltration (MF) and UF using hydrophilic mixed cellulose esters flat membranes with different pore size were used to clarify pomegranate juice. Results showed that the rejections of polyphenols with MF and UF membrane were 30% and 25%, respectively (Mirsaeedghazi et al., 2012). This indicates that the HF membrane performance was superior to flat sheet membranes due to its high surface area. On the other hand, the concentration of polarizations and fouling are the most important drawbacks for the industrial application of the UF membranes. In several studies natural organic matter, for example, polyphenolic extracts, was presented as the major UF membrane foulant. Upon the occurrence of fouling, the membrane would lose most of its permeability, and therefore chemical and/or physical treatments would be necessary to obtain the desired production rate (Schulz et al., 2017). The latter leads to an elevated energy consumption and cost, which makes the membranes economically less feasible for the natural antioxidants concentration.

12.1.4

Health benefits, safety assessment, and stability of pomegranate fruit extract

The main focus in any research directed toward the recovery of polyphenols from fruits and vegetables processing byproducts has been on the potential health benefits, which have triggered their implementation as functional food (Galanakis, 2012). In this regard, the production and consumption of pomegranate fruit is globally increasing due to

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their high antioxidant, antiinflammatory, and anticarcinogenic properties. Their applications have been extended in functional foods with their ability to prevent oil oxidation and vitamin destruction and preserve flavor and color (Ahmed et al., 2015; Devatkal and Naveena, 2010; Zhang et al., 2011). Oil oxidation is a free radical chain process leading to food rancidity, the destruction of vitamins (A, D, and E), and essential fatty acids, and the possible formation of toxic compounds and colored products. However for the commercial introduction of such products to the general public with the potential as functional foods, systematic sensory evaluation is also essential. As an example the enrichment of ice creams through the addition of pomegranate peel phenolics at 0.5% and 1.0% (w/w) led to significant improvement of its antioxidant and α-glucosidase-inhibitory (as a marker of antidiabetic effects for diabetes mellitus type 2) activities compared with the control sample. Moreover during its sensory evaluation, more than 75% of the panellists accepted the phenolic-enriched ice creams. Furthermore, their benefits for cardiovascular, prostate, and breast health have been researched on a systemic level based on molecular and cellular mechanisms (Al-Jarallah et al., 2013; Ammar et al., 2015; Anibal et al., 2013; Askari et al., 2014; Chrubasik-Hausmann et al., 2014). The effects of pomegranate juice and peel extracts, that is, their antimuˇ tagenic (Zahin et al., 2010), antineurodegenerative, antidiabetic (Savikin et al., 2018), antidepressant (Les et al., 2017), and antimicrobial activities (Ismail et al., 2012), have been also been presented in the clinical literature. A comprehensive review of the antiinflammatory and antiinfective effects of pomegranate fruit with a specific focus on the chemical constituents, phytochemistry, pharmacology, and toxicology has been published (Ismail et al., 2012). According to a literature review, nearly every part of the pomegranate plant has been investigated for various health-beneficial effects, including the fruit juice, peel, seeds, and leaves. Some of the recent investigations have been presented in Table 12.3.

12.1.4.1 Safety assessment Alongside the increasing claims of the health-beneficial properties of pomegranate and its products, their adverse effects have also been investigated (Patel et al., 2008). For this study the pomegranate fruit water extract was standardized to 30% punicalagins, which is the active ellagitannins responsible for over 50% of the antioxidant activity of the juice. Punicalagin is unique to pomegranate and has been introduced as a chemical marker for the authentication, quality control, and standardization of pomegranate products (Seeram et al., 2005). The intraperitoneal LD50 in rats and mice was determined as 217 and 187 mg/kg body weight, respectively. According to their results, the “no-observed-adverse-effect level” (NOAEL) was determined as 600 mg/kg body weight/day. However, for the commercial introduction and application of pomegranate-derived foodstuffs, safety evaluations should be also carried out in humans (Cerda´ et al., 2003).

12.1.4.2 Stability improvement One of the main drawbacks to the commercial application of natural polyphenols as antioxidants is their high activity, which makes them prone to chemical instability in environmental conditions, such as oxygen, moisture, etc. On the other hand most natural polyphenols show low solubility in nonpolar high-lipid matrixes, which may weaken or even suppress their full beneficial effects (Fang and Bhandari, 2010). In this regards, macro/nanoencapsulation of polyphenols, that is, their incorporation into biodegradable natural polymers, not only enhances their chemical stability, but also provides passive and active targeting and controlled release (Parisi et al., 2014). In research conducted for improving the solubility of polar pomegranate peel extract in a high-lipid content matrix, pomegranate peel extract was microencapsulated using maltodextrin/whey protein isolate (50:50) as a wall material by spray-drying techniques (Kaderides et al., 2015). The encapsulated phenolic extract improved the shelf life of hazelnut paste, in spite of the low solubility of the crude extract in such a high-lipid matrix. The optimum operating conditions for spray-drying were inlet air temperature 150 C, drying air flow rate 17.5 m3/h, ratio of wall to core material 9/1, and feed solid concentration 30% (w/w). Pomegranate seed oil with its high antioxidant characteristics and potential application in the food industries is also prone to oxidation. In order to overcome its early rancidity, it was microencapsulated by selecting skimmed milk powder as a wall material using a spray-drying technique (Goula and Adamopoulos, 2012) and the spray-dryer process condition was optimized. The optimum operating conditions were ratio of the core to the wall material 1:9, feed solids concentration 30% (w/w), inlet air temperature 187 C, and drying air flow rate 22.80 m3/h. Despite the well-known health-beneficial effects of pomegranate ellagitannins and their metabolites, they show limited in vivo bioavailability and short retention time. Ellagitannins upon arrival to the intestinal tract are hydrolyzed and converted to EA moieties and urolithins by colonic microbiota, respectively (Seeram et al., 2006). These compounds have limited absorption into systemic circulation and, after rapid metabolism in the liver, are excreted through urine (some persist in urine for up to 48 h), owing to their short half-life (Conte et al., 2016). To overcome this limitation poly(D,L-lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) nanoparticles (NPs) loaded with pomegranate

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TABLE 12.3 Health benefits of pomegranate derivatives. Health benefit

Main effect

Pomegranate part

Reference

Cardiovascular health

1—increase the activity of the HDL-associated paraoxonase 1 2—prevention of low-density lipoprotein (LDL) oxidation and cardiovascular disease

Juice

Selma et al. (2018), Aviram and Rosenblat (2013)

Hyperlipidemia

Cholesterol and high lipid levels
lowering effects

Juice

Esmaillzadeh et al. (2006)

Hypertension

High blood pressure lowering effect

50 mL juice, 1.5 mmol of total polyphenols per day, for 2 weeks

Shema-Didi et al. (2014)

Antiproliferative activity (antitumor and anticancer)

Colon and prostate tumor cells

Ellagitannin rich extracts

Kasimsetty et al. (2010)

Colorectal cancer

Polyphenol-rich fruit extracts

Majewska and Lewandowska (2017)

Antimetastatic effect on prostate cancer cells

Juice

Wang (2011), Askari et al. (2014), Wang and Martins-Green (2014)

Inhibit the proliferation of breast and prostate cancer cells

Peels and lamellas extract and hydrophilic fraction of seed oil extract

Orgil et al. (2014), ChrubasikHausmann et al. (2014), Costantini et al. (2014)

Inhibits skin tumorigenesis

Hydrolyzable tannin-rich pomegranate fruit extract

Afaq et al. (2005)

Antimicrobial properties

Antibacterial and antifungal activities on selected bacteria and fungi

Pomegranate peel extract, seed extract, juice, and whole fruit

Kharchoufi et al. (2018)

Antiinflammatory activity

Inflammation play a role in obesity, heart disease, and cancer

Extracts from peels, flowers, seeds, and juice

Verardo et al. (2014), Du et al. (2018), Costantini et al. (2014)

Neuroprotective

Prevent the neonatal brain injury, ischemia and Alzheimer

Juice

Loren et al. (2005)

Antidiabetic and antihyperlipidemic effects

Evaluated in alloxan-induced noninsulin-dependent diabetes mellitus albino rats

Ethanolic extract of leaves of pomegranates

Das and Barman (2012)

Antiviral effects

Inhibited the replication of human influenza A/Hong Kong (H3N2) in vitro

Pomegranate peel extracts

Haidari et al. (2009)

Provides an HIV-1 entry inhibitor and candidate topical microbicide

Juice

Neurath et al. (2005)

extract were prepared by the modified emulsion
solvent evaporation method (Shirode et al., 2015). The results revealed that PLGA-PEG NPs were efficiently taken up in breast cancer cells and the uptake reached the maximum at 24 h. Therefore through the nanoencapsulation of pomegranate polyphenols, the targeted delivery of active polyphenols to the breast cancer cells occurred and their anticancer effects were enhanced.

12.1.5

Concluding remarks

Due to numerous research conducted on the antioxidant and health benefit properties of various parts of pomegranate, including the whole fruit, the juice, and the peel, the beverage, food, and cosmetic industries have become interested in enriching their products with pomegranate extracts and thus improving them (Rymon, 2011). This has led to the rapid growth and interest in the commercial applications of pomegranate and its derivatives in food products and medicinal supplements. During a study conducted on 19 pomegranate supplements in the retail market in the United States, it was found that in 13 of them low levels or no detectable pomegranate tannins existed. The authenticity and quality of

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pomegranate supplements were studied by determining tannins composition, including punicalagin, punicalin, ellagitannins and gallotannins, using reverse phase HPLC. Only six products had polyphenol compositions resembling pomegranates (Madrigal-Carballo et al., 2009). Therefore the evaluation of the legitimacy of the commercially available pomegranate products is of paramount importance since these products are claimed to have health benefits due to high antioxidant content. In this regard, the regulation of their manufacturing through the introduction of systematic standardization is highly essential. Pomegranate-based product labels must be consistent with the pomegranate polyphenol composition and correlate with the actual content of antioxidants, polyphenols, or tannins. The establishment of systematic standards, including well-documented universal analysis methods, will lead to more reliable and reproducible labeling information, which will lead to both improving consumer confidence in the quality of products and the market regulation of commercially available pomegranate products. On the other hand for the commercialization of pomegranate products, the establishment of economically feasible extraction methods through reductions in the process steps and operating costs, the use of an environment-friendly extraction solvent and its recovery, and the minimization of waste are also of paramount importance.

References Abbasi, H., Rezaei, K., Rashidi, L., 2008. Extraction of essential oils from the seeds of pomegranate using organic solvents and supercritical CO2. J. Am. Oil Chem. Soc. 85, 83
89. Available from: https://doi.org/10.1007/s11746-007-1158-x. Abid, M., Cheikhrouhou, S., Renard, C.M.G.C., Bureau, S., Cuvelier, G., Attia, H., Ayadi, M.A.A., 2017. Characterization of pectins extracted from pomegranate peel and their gelling properties. Food Chem. 215, 318
325. Available from: https://doi.org/10.1016/j.foodchem.2016.07.181. Adams, L.S., Seeram, N.P., Aggarwal, B.B., Takada, Y., Sand, D., Heber, D., 2006. Pomegranate juice, total pomegranate ellagitannins, and punicalagin suppress inflammatory cell signaling in colon cancer cells. J. Agric. Food Chem. 54, 980
985. Available from: https://doi.org/10.1021/ jf052005r. Afaq, F., Saleem, M., Krueger, C.G., Reed, J.D., Mukhtar, H., 2005. Anthocyanin- and hydrolyzable tannin-rich pomegranate fruit extract modulates MAPK and NF-κB pathways and inhibits skin tumorigenesis in CD-1 mice. Int. J. Cancer 113, 423
433. Available from: https://doi.org/10.1002/ ijc.20587. Ahmed, S.T., Islam, M.M., Bostami, A.B.M.R., Mun, H.S., Kim, Y.J., Yang, C.J., 2015. Meat composition, fatty acid profile and oxidative stability of meat from broilers supplemented with pomegranate (Punica granatum L.) by-products. Food Chem. 188, 481
488. Available from: https://doi. org/10.1016/j.foodchem.2015.04.140. Akhtar, S., Ismail, T., Fraternale, D., Sestili, P., 2015. Pomegranate peel and peel extracts: chemistry and food features. Food Chem. Available from: https://doi.org/10.1016/j.foodchem.2014.11.035. Althunibat, O.Y., Al-Mustafa, A.H., Tarawneh, K., Khleifat, K.M., Ridzwan, B.H., Qaralleh, H.N., 2010. Protective role of Punica granatum L. peel extract against oxidative damage in experimental diabetic rats. Process Biochem. 45, 581
585. Available from: https://doi.org/10.1016/j. procbio.2009.12.004. Al-Jarallah, A., Igdoura, F., Zhang, Y., Tenedero, C.B., White, E.J., MacDonald, M.E., et al., 2013. The effect of pomegranate extract on coronary artery atherosclerosis in SR-BI/APOE double knockout mice. Atherosclerosis 228, 80
89. Available from: https://doi.org/10.1016/j. atherosclerosis.2013.02.025. Ammar, A.E., Esmat, A., Hassona, M.D.H., Tadros, M.G., Abdel-Naim, A.B., Guns, E.S.T., 2015. The effect of pomegranate fruit extract on testosterone-induced BPH in rats. Prostate 75, 679
692. Available from: https://doi.org/10.1002/pros.22951. Amyrgialaki, E., Makris, D.P., Mauromoustakos, A., Kefalas, P., 2014. Optimisation of the extraction of pomegranate (Punica granatum) husk phenolics using water/ethanol solvent systems and response surface methodology. Ind. Crops Prod. 59, 216
222. Available from: https://doi.org/ 10.1016/j.indcrop.2014.05.011. Anibal, P.C., Peixoto, I.T.A., Foglio, M.A., Ho¨fling, J.F., 2013. Antifungal activity of the ethanolic extracts of Punica granatum L. and evaluation of the morphological and structural modifications of its compounds upon the cells of Candida spp. Braz. J. Microbiol. 44, 839
848. Available from: https://doi.org/10.1590/S1517-83822013005000060. Anonymous, 2009. Report on the production, export and industrial processing of pomegranate, Ministry of Industries, Mining and trade, office of Non-Metallic industries, Tehran, Iran (translated from Persian). Askari, F., Parizi, M.K., Jessri, M., Rashidkhani, B., 2014. Fruit and vegetable intake in relation to prostate cancer in Iranian men: a case-control study. Asian Pac. J. Cancer Prev. 15, 5223
5227. Available from: https://doi.org/10.7314/APJCP.2014.15.13.5223. Aviram, M., Rosenblat, M., 2013. Pomegranate for your cardiovascular health. rambam maimonides. Med. J. 4, e0013. Available from: https://doi.org/ 10.5041/RMMJ.10113. Baklouti, S., Ellouze-Ghorbel, R., Mokni, A., Chaabouni, 2012. Clarification of pomegranate juice by ultrafiltration: study of juice quality and of the fouling mechanism. Fruits 67, 215
225. Available from: https://doi.org/10.1051/fruits/2012010. Barba, F.J., Galanakis, C.M., Esteve, M.J., Frigola, A., Vorobiev, E., 2015. Potential use of pulsed electric technologies and ultrasounds to improve the recovery of high-added value compounds from blackberries. J. Food Eng. 167, 38
44. Available from: https://doi.org/10.1016/j. jfoodeng.2015.02.001.

274

Valorization of Fruit Processing By-products

Ben-Ali, S., Akermi, A., Mabrouk, M., Ouederni, A., 2018. Optimization of extraction process and chemical characterization of pomegranate peel extract. Chem. Pap. 1
14. Available from: https://doi.org/10.1007/s11696-018-0427-5. Bhornsmithikun, V., Chetpattananondh, P., Yamsaengsung, R., Prasertsit, K., 2010. Continuous extraction of prebiotics from jackfruit seeds. Songklanakarin J. Sci. Technol. 32, 635
642. Boggia, R., Turrini, F., Villa, C., Lacapra, C., Zunin, P., Parodi, B., 2016. Green extraction from pomegranate marcs for the production of functional foods and cosmetics. Pharmaceuticals 9. Available from: https://doi.org/10.3390/ph9040063. C ¸ am, M., Hi¸sil, Y., 2010. Pressurised water extraction of polyphenols from pomegranate peels. Food Chem. 123, 878
885. Available from: https:// doi.org/10.1016/j.foodchem.2010.05.011. Borochov-Neori, H., Judeinstein, S., Tripler, E., Harari, M., Greenberg, A., Shomer, I., Holland, D., 2009. Seasonal and cultivar variations in antioxidant and sensory quality of pomegranate (Punica granatum L.) fruit. J. Food Compos. Anal. 22, 189
195. Available from: https://doi.org/ 10.1016/j.jfca.2008.10.011. Brinckmann, J., 2011. Taking a closer look at the pomegranate fruit trade from Africa. In: Market News Service for Medicinal Plants & Extracts, Geneva, Switzerland, pp. 7
13. Cacace, J.E., Mazza, G., 2003. Mass transfer process during extraction of phenolic compounds from milled berries. J. Food Eng. 59, 379
389. Available from: https://doi.org/10.1016/S0260-8774(02)00497-1. C ¸ am, M., ˙Ic¸yer, N.C., Erdo˘gan, F., Ic¸yer, N.C., Erdogˇan, F., 2014. Pomegranate peel phenolics: microencapsulation, storage stability and potential ingredient for functional food development. LWT - Food Sci. Technol. 55, 117
123. Available from: https://doi.org/10.1016/j.lwt.2013.09.011. Cassano, A., Conidi, C., Drioli, E., 2011. Clarification and concentration of pomegranate juice (Punica granatum L.) using membrane processes. J. Food Eng. 107, 366
373. Available from: https://doi.org/10.1016/j.jfoodeng.2011.07.002. Castro-Lo´pez, C., Ventura-Sobrevilla, J.M., Gonza´lez-Herna´ndez, M.D., Rojas, R., Ascacio-Valde´s, J.A., Aguilar, C.N., et al., 2017. Impact of extraction techniques on antioxidant capacities and phytochemical composition of polyphenol-rich extracts. Food Chem. 237, 1139
1148. Available from: https://doi.org/10.1016/j.foodchem.2017.06.032. Cerda´, B., Cero´n, J.J., Toma´s-Barbera´n, F.A., Espı´n, J.C., 2003. Repeated oral administration of high doses of the pomegranate ellagitannin punicalagin to rats for 37 days is not toxic. J. Agric. Food Chem. 51, 3493
3501. Available from: https://doi.org/10.1021/jf020842c. Chandra, A., Rana, J., Li, Y., 2001. Separation, identification, quantification, and method validation of anthocyanins in botanical supplement raw materials by HPLC and HPLC-MS. J. Agric. Food Chem. 49, 3515
3521. Available from: https://doi.org/10.1021/jf010389p. Chen, S., Xing, X.H., Huang, J.J., Xu, M.S., 2011. Enzyme-assisted extraction of flavonoids from Ginkgo biloba leaves: improvement effect of flavonol transglycosylation catalyzed by Penicillium decumbens cellulase. Enzyme Microb. Technol. 48, 100
105. Available from: https://doi.org/ 10.1016/j.enzmictec.2010.09.017. Chrubasik-Hausmann, S., Vlachojannis, C., Zimmermann, B., 2014. Pomegranate juice and prostate cancer: importance of the characterisation of the active principle. Phytother. Res. 28, 1676
1678. Available from: https://doi.org/10.1002/ptr.5181. Conte, R., Calarco, A., Napoletano, A., Valentino, A., Margarucci, S., Di Cristo, F., et al., 2016. Polyphenols nanoencapsulation for therapeutic applications. J. Biomol. Res. Ther. 5, 13. Available from: https://doi.org/10.4172/2167-7956.1000139. Costantini, S., Rusolo, F., De Vito, V., Moccia, S., Picariello, G., Capone, F., et al., 2014. Potential anti-inflammatory effects of the hydrophilic fraction of pomegranate (Punica granatum L.) Seed oil on breast cancer cell lines. Molecules 19, 8644
8660. Available from: https://doi.org/ 10.3390/molecules19068644. Das, S., Barman, S., 2012. Antidiabetic and antihyperlipidemic effects of ethanolic extract of leaves of Punica granatum in alloxan-induced non
insulin-dependent diabetes mellitus albino rats. Indian J. Pharmacol. 44, 219. Devatkal, S.K., Naveena, B.M., 2010. Effect of salt, kinnow and pomegranate fruit by-product powders on color and oxidative stability of raw ground goat meat during refrigerated storage. Meat Sci. 85, 306
311. Available from: https://doi.org/10.1016/j.meatsci.2010.01.019. Du, L., Li, J., Zhang, X., Wang, L., Zhang, W., 2018. Pomegranate peel polyphenols inhibits inflammation in LPS-induced RAW264.7 macrophages via the suppression of MAPKs activation. J. Funct. Foods 43, 62
69. Available from: https://doi.org/10.1016/j.jff.2018.01.028. Durante, M., Montefusco, A., Marrese, P.P., Soccio, M., Pastore, D., Piro, G., et al., 2017. Seeds of pomegranate, tomato and grapes: an underestimated source of natural bioactive molecules and antioxidants from agri-food by-products. J. Food Compos. Anal. 63, 65
72. Available from: https://doi.org/10.1016/j.jfca.2017.07.026. Dı´az-Reinoso, B., Moure, A., Domı´nguez, H., Parajo´, J.C., 2009. Ultra- and nanofiltration of aqueous extracts from distilled fermented grape pomace. J. Food Eng. 91, 587
593. Available from: https://doi.org/10.1016/j.jfoodeng.2008.10.007. Dı´az-Reinoso, B., Moure, A., Domı´nguez, H., Parajo´, J.C., 2006. Supercritical CO2 extraction and purification of compounds with antioxidant activity. J. Agric. Food Chem. Available from: https://doi.org/10.1021/jf052858j. Eikani, M.H., Golmohammad, F., Homami, S.S., 2012. Extraction of pomegranate (Punica granatum L.) seed oil using superheated hexane. Food Bioprod. Process. 90, 32
36. Available from: https://doi.org/10.1016/j.fbp.2011.01.002. El-Abbassi, A., Hafidi, A., Garcı´a-Payo, M.C., Khayet, M., 2009. Concentration of olive mill wastewater by membrane distillation for polyphenols recovery. Desalination 245, 670
674. Available from: https://doi.org/10.1016/j.desal.2009.02.035. Esmaillzadeh, A., Tahbaz, F., Gaieni, I., Alavi-Majd, H., Azadbakht, L., 2006. Cholesterol-lowering effect of concentrated pomegranate juice consumption in type II diabetic patients with hyperlipidemia. Int. J. Vitam. Nutr. Res. 76, 147
151. Fang, Z., Bhandari, B., 2010. Encapsulation of polyphenols—a review. Trends Food Sci. Technol. 21, 510
523. Available from: https://doi.org/ 10.1016/j.tifs.2010.08.003.

Pomegranate Chapter | 12

275

Fischer, U.A., Carle, R., Kammerer, D.R., 2011. Identification and quantification of phenolic compounds from pomegranate (Punica granatum L.) peel, mesocarp, aril and differently produced juices by HPLC-DAD-ESI/MSn. Food Chem. 127, 807
821. Available from: https://doi.org/ 10.1016/j.foodchem.2010.12.156. Fischer, U.A., Carle, R., Kammerer, D.R., 2013. Thermal stability of anthocyanins and colourless phenolics in pomegranate (Punica granatum L.) juices and model solutions. Food Chem. 138, 1800
1809. Available from: https://doi.org/10.1016/j.foodchem.2012.10.072. Galanakis, C.M., 2013. Emerging technologies for the production of nutraceuticals from agricultural by-products: a viewpoint of opportunities and challenges. Food Bioprod. Process. Available from: https://doi.org/10.1016/j.fbp.2013.01.004. Galanakis, C.M., 2012. Recovery of high added-value components from food wastes: conventional, emerging technologies and commercialized applications. Trends Food Sci. Technol. 26, 68
87. Available from: https://doi.org/10.1016/j.tifs.2012.03.003. Galanakis, C.M., Schieber, A., 2014. Editorial. Food Res. Int. 65, 299
300. Available from: https://doi.org/10.1016/j.foodres.2014.11.019. Giacobbo, A., Do Prado, J.M., Meneguzzi, A., Bernardes, A.M., De Pinho, M.N., 2015. Microfiltration for the recovery of polyphenols from winery effluents. Sep. Purif. Technol. 143, 12
18. Available from: https://doi.org/10.1016/j.seppur.2015.01.019. Gil, M.I., Tomas-Barberan, F.A., Hess-Pierce, B., Holcroft, D.M., Kader, A.A., 2000. Antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing. J. Agric. Food Chem. 48, 4581
4589. Available from: https://doi.org/10.1021/jf000404a. Goula, A.M., Adamopoulos, K.G., 2012. A method for pomegranate seed application in food industries: seed oil encapsulation. Food Bioprod. Process. 90, 639
652. Available from: https://doi.org/10.1016/j.fbp.2012.06.001. Goula, A.M., Ververi, M., Adamopoulou, A., Kaderides, K., 2017. Green ultrasound-assisted extraction of carotenoids from pomegranate wastes using vegetable oils. Ultrason. Sonochem. 34, 821
830. Available from: https://doi.org/10.1016/j.ultsonch.2016.07.022. Goula, A.M., Papatheodorou, A., Karasavva, S., Kaderides, K., 2018. Ultrasound-assisted aqueous enzymatic extraction of oil from pomegranate seeds. Waste Biomass Valori. 9. Available from: https://doi.org/10.1007/s12649-016-9740-9. Hagerman, A.E., Riedl, K.M., Jones, G.A., Sovik, K.N., Ritchard, N.T., Hartzfeld, P.W., Riechel, T.L., 1998. High molecular weight plant polyphenolics (tannins) as biological antioxidants. J. Agric. Food Chem. 46, 1887
1892. Haidari, M., Ali, M., Casscells III, S.W., Madjid, M., 2009. Pomegranate (Punica granatum) purified polyphenol extract inhibits influenza virus and has a synergistic effect with oseltamivir. Phytomedicine 16, 1127
1136. Hasnaoui, N., Wathelet, B., Jime´nez-Araujo, A., 2014. Valorization of pomegranate peel from 12 cultivars: dietary fibre composition, antioxidant capacity and functional properties. Food Chem. 160, 196
203. Available from: https://doi.org/10.1016/j.foodchem.2014.03.089. He, B., Zhang, L.L., Yue, X.Y., Liang, J., Jiang, J., Gao, X.L., et al., 2016. Optimization of ultrasound-assisted extraction of phenolic compounds and anthocyanins from blueberry (Vaccinium ashei) wine pomace. Food Chem. 204, 70
76. Available from: https://doi.org/10.1016/j. foodchem.2016.02.094. ˇ et al., 2012. Subcritical water extraction of phenolic compounds from pomegranate (Punica He, L., Zhang, X., Xu, H., Xu, C., Yuan, F., Knez, Z., granatum L.) seed residues and investigation into their antioxidant activities with HPLC-ABTS 1 assay. Food Bioprod. Process. 90, 215
223. Available from: https://doi.org/10.1016/j.fbp.2011.03.003. Heydari Majd, M., Rajaei, A., Salar Bashi, D., Mortazavi, S.A., Bolourian, S., 2014. Optimization of ultrasonic-assisted extraction of phenolic compounds from bovine pennyroyal (Phlomidoschema parviflorum) leaves using response surface methodology. Ind. Crops Prod. 57, 195
202. Available from: https://doi.org/10.1016/j.indcrop.2014.03.031. Hong, V., Wrolstad, R.E., 1990. Use of HPLC separation photodiode array detection for characterization of anthocyanins. J. Agric. Food Chem. 38, 708
715. Huang, D., Boxin, O.U., Prior, R.L., 2005. The chemistry behind antioxidant capacity assays. J. Agric. Food Chem. Available from: https://doi.org/ 10.1021/jf030723c. Ibrahim Kahramanoglu, S.U., 2016. Pomegranate Production and Marketing, first ed. CRC Press Taylor & Francis Group, Boca Raton, FL. Ismail, T., Sestili, P., Akhtar, S., 2012. Pomegranate peel and fruit extracts: a review of potential anti-inflammatory and anti-infective effects. J. Ethnopharmacol. 143, 397
405. Available from: https://doi.org/10.1016/j.jep.2012.07.004. Kaderides, K., Goula, A.M., Adamopoulos, K.G., 2015. A process for turning pomegranate peels into a valuable food ingredient using ultrasound-assisted extraction and encapsulation. Innov. Food Sci. Emerg. Technol. 31, 204
215. Available from: https://doi.org/10.1016/j. ifset.2015.08.006. Karacabey, E., Mazza, G., 2010. Optimisation of antioxidant activity of grape cane extracts using response surface methodology. Food Chem. 119, 343
348. Available from: https://doi.org/10.1016/j.foodchem.2009.06.029. Kasimsetty, S.G., Bialonska, D., Reddy, M.K., Ma, G., Khan, S.I., Ferreira, D., 2010. Colon cancer chemopreventive activities of pomegranate ellagitannins and urolithins. J. Agric. Food Chem. 58, 2180
2187. Kazemi, M., Karim, R., Mirhosseini, H., Abdul Hamid, A., 2016. Optimization of pulsed ultrasound-assisted technique for extraction of phenolics from pomegranate peel of Malas variety: punicalagin and hydroxybenzoic acids. Food Chem. 206, 156
166. Available from: https://doi.org/ 10.1016/j.foodchem.2016.03.017. Kapasakalidis, P.G., Rastall, R.A., Gordon, M.H., 2009. Effect of a cellulase treatment on extraction of antioxidant phenols from black currant (Ribes nigrum L.) pomace. J. Agric. Food Chem. 57, 4342
4351. Available from: https://doi.org/10.1021/jf8029176. Kharchoufi, S., Licciardello, F., Siracusa, L., Muratore, G., Hamdi, M., Restuccia, C., 2018. Antimicrobial and antioxidant features of ‘Gabsiʼ pomegranate peel extracts. Ind. Crops Prod. 111, 345
352. Available from: https://doi.org/10.1016/j.indcrop.2017.10.037. Kushwaha, S.C., Bera, M.B., Kumar, P., 2015. An economical approach for production of purified ellagitannin powder from fresh and fermented pomegranate peel. J. Agric. Eng. Food Technol. 2, 17
21.

276

Valorization of Fruit Processing By-products

Les, F., Carpe´ne´, C., Arbone´s-Mainar, J.M., Decaunes, P., Valero, M.S., Lo´pez, V., 2017. Pomegranate juice and its main polyphenols exhibit direct effects on amine oxidases from human adipose tissue and inhibit lipid metabolism in adipocytes. J. Funct. Foods 33, 323
331. Available from: https://doi.org/10.1016/j.jff.2017.04.006. Lestari, D., Mulder, W., Sanders, J., 2010. Improving Jatropha curcas seed protein recovery by using counter current multistage extraction. Biochem. Eng. J. 50, 16
23. Available from: https://doi.org/10.1016/j.bej.2010.02.011. Li, Y., Guo, C., Yang, J., Wei, J., Xu, J., Cheng, S., 2006. Evaluation of antioxidant properties of pomegranate peel extract in comparison with pomegranate pulp extract. Food Chem. 96, 254
260. Available from: https://doi.org/10.1016/j.foodchem.2005.02.033. Liu, D., Vorobiev, E., Savoire, R., Lanoiselle´, J.L., 2011. Intensification of polyphenols extraction from grape seeds by high voltage electrical discharges and extract concentration by dead-end ultrafiltration. Sep. Purif. Technol. Available from: https://doi.org/10.1016/j. seppur.2011.07.012. Liu, G., Xu, X., Gong, Y., He, L., Gao, Y., 2012. Effects of supercritical CO 2 extraction parameters on chemical composition and free radicalscavenging activity of pomegranate (Punica granatum L.) seed oil. Food Bioprod. Process. 90, 573
578. Available from: https://doi.org/10.1016/ j.fbp.2011.11.004. Liu, Y., Wei, S., Liao, M., 2013. Optimization of ultrasonic extraction of phenolic compounds from Euryale ferox seed shells using response surface methodology. Ind. Crops Prod. 49, 837
843. Available from: https://doi.org/10.1016/j.indcrop.2013.07.023. Liu, G., Xu, X., Hao, Q., Gao, Y., 2009. Supercritical CO2 extraction optimization of pomegranate (Punica granatum L.) seed oil using response surface methodology. LWT-Food Sci. Technol. 42, 1491
1495. Available from: https://doi.org/10.1016/j.lwt.2009.04.011. Loren, D.J., Seeram, N.P., Schulman, R.N., Holtzman, D.M., 2005. Maternal dietary supplementation with pomegranate juice is neuroprotective in an animal model of neonatal hypoxic-ischemic brain injury. Pediatr. Res. 57, 858
864. Available from: https://doi.org/10.1203/01. PDR.0000157722.07810.15. Madrigal-Carballo, S., Rodriguez, G., Krueger, C.G., Dreher, M., Reed, J.D., 2009. Pomegranate (Punica granatum) supplements: authenticity, antioxidant and polyphenol composition. J. Funct. Foods 1, 324
329. Available from: https://doi.org/10.1016/j.jff.2009.02.005. Majewska, M., Lewandowska, U., 2017. The chemopreventive and anticancer potential against colorectal cancer of polyphenol-rich fruit extracts. Food Rev. Int. 1
20. Available from: https://doi.org/10.1080/87559129.2017.1307388. Markom, M., Hasan, M., Daud, W.R.W., Singh, H., Jahim, J.M., 2007. Extraction of hydrolysable tannins from Phyllanthus niruri Linn.: effects of solvents and extraction methods. Sep. Purif. Technol. 52, 487
496. Mirdehghan, S.H., Rahemi, M., 2007. Seasonal changes of mineral nutrients and phenolics in pomegranate (Punica granatum L.) fruit. Sci. Hortic. (Amsterdam). 111, 120
127. Available from: https://doi.org/10.1016/j.scienta.2006.10.001. Mirsaeedghazi, H., Mousavi, S.M., Emam-Djomeh, Z., Rezaei, K., Aroujalian, A., Navidbakhsh, M., 2012. Comparison between ultrafiltration and microfiltration in the clarification of pomegranate juice. J. Food Process Eng. 35, 424
436. Available from: https://doi.org/10.1111/j.17454530.2010.00598.x. Moorthy, I.G.G., Maran, J.P.P., Surya, S.M.M., Naganyashree, S., Shivamathi, C.S.S., 2015. Response surface optimization of ultrasound assisted extraction of pectin from pomegranate peel. Int. J. Biol. Macromol. 72, 1323
1328. Available from: https://doi.org/10.1016/j. ijbiomac.2014.10.037. Nag, S., Sit, N., 2018. Optimization of ultrasound assisted enzymatic extraction of polyphenols from pomegranate peels based on phytochemical content and antioxidant property. J. Food Meas. Charact. 0, 1
10. Available from: https://doi.org/10.1007/s11694-018-9788-2. Nawaz, H., Shi, J., Mittal, G.S., Kakuda, Y., 2006. Extraction of polyphenols from grape seeds and concentration by ultrafiltration. Sep. Purif. Technol. 48, 176
181. Available from: https://doi.org/10.1016/j.seppur.2005.07.006. Negi, P.S., Jayaprakasha, G.K., 2003. Antioxidant and antibacterial activities of punica granatum peel extracts. J. Food Sci. 68, 1473
1477. Neurath, A.R., Strick, N., Li, Y.Y., Debnath, A.K., 2005. Punica granatum (pomegranate) juice provides an HIV-1 entry inhibitor and candidate topical microbicide. Ann. N. Y. Acad. Sci. 1056, 311
327. Ng, L.Y., Leo, C.P., Mohammad, A.W., 2011. Optimizing the incorporation of silica nanoparticles in polysulfone/poly (vinyl alcohol) membranes with response surface methodology. J. Appl. Polym. Sci. 121, 1804
1814. Orgil, O., Schwartz, E., Baruch, L., Matityahu, I., Mahajna, J., Amir, R., 2014. The antioxidative and anti-proliferative potential of non-edible organs of the pomegranate fruit and tree. LWT - Food Sci. Technol. 58, 571
577. Available from: https://doi.org/10.1016/j. lwt.2014.03.030. Pan, Z., Qu, W., Ma, H., Atungulu, G.G., McHugh, T.H., 2012. Continuous and pulsed ultrasound-assisted extractions of antioxidants from pomegranate peel. Ultrason. Sonochem. 19, 365
372. Available from: https://doi.org/10.1016/j.ultsonch.2011.05.015. Parisi, O.I., Puoci, F., Restuccia, D., Farina, G., Iemma, F., Picci, N., 2014. Polyphenols and their formulations: different strategies to overcome the drawbacks associated with their poor stability and bioavailability. In: Watson, R.R., Victor, R., Preedy, S.Z. (Eds.), Polyphenols in Human Health and Disease. Elsevier Inc, pp. 29
45. ,https://doi.org/10.1016/B978-0-12-398456-2.00004-9.. Patel, C., Dadhaniya, P., Hingorani, L., Soni, M.G., 2008. Safety assessment of pomegranate fruit extract: acute and subchronic toxicity studies. Food Chem. Toxicol. 46, 2728
2735. Available from: https://doi.org/10.1016/j.fct.2008.04.035. Persson, K.M., Gekas, V., Tra¨ga˚rdh, G., 1995. Study of membrane compaction and its influence on ultrafiltration water permeability. J. Membr. Sci. 100, 155
162. Available from: https://doi.org/10.1016/0376-7388(94)00263-X. Pinela, J., Prieto, M.A., Barros, L., Carvalho, A.M., Oliveira, M.B.P.P., Saraiva, J.A., et al., 2017. Cold extraction of phenolic compounds from watercress by high hydrostatic pressure: process modelling and optimization. Sep. Purif. Technol. 192, 501
512. Available from: https://doi.org/ 10.1016/j.seppur.2017.10.007.

Pomegranate Chapter | 12

277

Pinelo, M., Manzocco, L., Nun˜ez, M.J., Nicoli, M.C., 2004. Interaction among phenols in food fortification: negative synergism on antioxidant capacity. J. Agric. Food Chem. 52, 1177
1180. Pinelo, M., Rubilar, M., Jerez, M., Sineiro, J., Nu´n˜ez, M.J., 2005. Effect of solvent, temperature, and solvent-to-solid ratio on the total phenolic content and antiradical activity of extracts from different components of grape pomace. J. Agric. Food Chem. 53, 2111
2117. Available from: https://doi.org/10.1021/jf0488110. Pinto, P.R., Mota, I.F., Pereira, C.M., Ribeiro, A.M., Loureiro, J.M., Rodrigues, A.E., 2017. Separation and recovery of polyphenols and carbohydrates from Eucalyptus bark extract by ultrafiltration/diafiltration and adsorption processes. Sep. Purif. Technol. 183, 96
105. Available from: https:// doi.org/10.1016/j.seppur.2017.04.003. Qu, W., Pan, Z., Ma, H., 2010. Extraction modeling and activities of antioxidants from pomegranate marc. J. Food Eng. 99, 16
23. Available from: https://doi.org/10.1016/j.jfoodeng.2010.01.020. Ranjbar, N., Eikani, M.H., Javanmard, M., Golmohammad, F., 2016. Impact of instant controlled pressure drop on phenolic compounds extraction from pomegranate peel. Innov. Food Sci. Emerg. Technol. 37, 177
183. Available from: https://doi.org/10.1016/j.ifset.2016.08.017. Ren, D., Zhao, Y., Nie, Y., Lu, X., Sun, Y., Yang, X., 2014. Chemical composition of Pleurotus eryngii polysaccharides and their inhibitory effects on high-fructose diet-induced insulin resistance and oxidative stress in mice. Food Funct. 5, 2609
2620. Available from: https://doi.org/10.1039/ c3fo60640f. Rosello´-Soto, E., Galanakis, C.M., Brnˇci´c, M., Orlien, V., Trujillo, F.J., Mawson, R., et al., 2015. Clean recovery of antioxidant compounds from plant foods, by-products and algae assisted by ultrasounds processing. Modeling approaches to optimize processing conditions. Trends Food Sci. Technol. 42, 134
149. Available from: https://doi.org/10.1016/j.tifs.2015.01.002. Russo, M., Fanali, C., Tripodo, G., Dugo, P., Muleo, R., Dugo, L., et al., 2018. Analysis of phenolic compounds in different parts of pomegranate (Punica granatum) fruit by HPLC-PDA-ESI/MS and evaluation of their antioxidant activity: application to different Italian varieties. Anal. Bioanal. Chem. 410, 3507
3520. Available from: https://doi.org/10.1007/s00216-018-0854-8. Rymon, D., 2011. Mapping features of the global pomegranate market. Acta Hortic. 890, 599
602. Available from: https://doi.org/10.17660/ ActaHortic.2011.890.84. Saad, H., Charrier-El Bouhtoury, F., Pizzi, A., Rode, K., Charrier, B., Ayed, N., 2012. Characterization of pomegranate peels tannin extractives. Ind. Crops Prod. 40, 239
246. Available from: https://doi.org/10.1016/j.indcrop.2012.02.038. Safavi, K., Rajaian, H., Nazifi, S., 2014. The effect of hydroalcoholic extract of Punica granatum flower on coagulation parameters in rats. Comp. Clin. Path. 23, 1757
1762. Saffarzadeh-Matin, S., Khosrowshahi, F.M., 2017. Phenolic compounds extraction from Iranian pomegranate (Punica granatum) industrial waste applicable to pilot plant scale. Ind. Crops Prod. 108, 583
597. Available from: https://doi.org/10.1016/j.indcrop.2017.07.022. Saffarzadeh-Matin, S., Masoudi-Khosrowshahi, F., 2018. Simultaneous separation and concentration of polyphenols from pomegranate industrial waste by multistage counter-current system; comparing with ultrafiltration concentration. Sep. Purif. Technol. 204, 261
275. Available from: https:// doi.org/10.1016/j.seppur.2018.04.083. Saleh, Z.S., Stanley, R., Wibisono, R., 2006. Separation and concentration of health compounds by membrane filtration. Int. J. Food Eng. 2. Available from: https://doi.org/10.2202/1556-3758.1125. ˇ ˇ Savikin, K., Zivkovi´ c, J., Alimpi´c, A., Zduni´c, G., Jankovi´c, T., Duleti´c-Lauˇsevi´c, S., et al., 2018. Activity guided fractionation of pomegranate extract and its antioxidant, antidiabetic and antineurodegenerative properties. Ind. Crops Prod. 113, 142
149. Available from: https://doi.org/10.1016/j. indcrop.2018.01.031. Seeram, N.P., Aronson, W.J., Zhang, Y., Henning, S.M., Moro, A., Lee, R.-p, et al., 2007. Pomegranate ellagitannin-derived metabolites inhibit prostate cancer growth and localize to the mouse prostate gland. J. Agric. Food Chem. 55, 7732
7737. Schulz, M., Winter, J., Wray, H., Barbeau, B., Be´rube´, P., 2017. Biologically active ion exchange (BIEX) for NOM removal and membrane fouling prevention. Water Sci. Technol. Water Supply 17, 1178
1184. Available from: https://doi.org/10.2166/ws.2017.016. Seeram, N., Lee, R., Hardy, M., Heber, D., 2005. Rapid large scale purification of ellagitannins from pomegranate husk, a by-product of the commercial juice industry. Sep. Purif. Technol. 41, 49
55. Available from: https://doi.org/10.1016/j.seppur.2004.04.003. Seeram, N.P., Henning, S.M., Zhang, Y., Suchard, M., Li, Z., Heber, D., 2006. Pomegranate juice ellagitannin metabolites are present in human plasma and some persist in urine for up to 48 hours. J. Nutr. 136, 2481
2485. Available from: https://doi.org/10.1093/jn/136.10.2481. ¨ rem, A., 2018. Toma´s-Barbera´n, The gut microbiota Selma, M.V., Gonza´lez-Sarrı´as, A., Salas-Salvado´, J., Andre´s-Lacueva, C., Alasalvar, C., O metabolism of pomegranate or walnut ellagitannins yields two urolithin-metabotypes that correlate with cardiometabolic risk biomarkers: Comparison between normoweight, overweight-obesity and metabolic syndrome. Clin. Nutr. 37, 897
905. Available from: https://doi.org/ 10.1016/j.clnu.2017.03.012. Shema-Didi, L., Kristal, B., Sela, S., Geron, R., Ore, L., 2014. Does pomegranate intake attenuate cardiovascular risk factors in hemodialysis patients? Nutr. J. 13, 18. Shirode, A.B., Bharali, D.J., Nallanthighal, S., Coon, J.K., Mousa, S.A., Reliene, R., 2015. Nanoencapsulation of pomegranate bioactive compounds for breast cancer chemoprevention. Int. J. Nanomed. 10, 475
484. Available from: https://doi.org/10.2147/IJN.S65145. Simone, S., Conidi, C., Ursino, C., Cassano, A., Figoli, A., 2016. Clarification of orange press liquors by PVDF hollow fiber membranes. Membranes (Basel) 6. Available from: https://doi.org/10.3390/membranes6010009. Singh, B., Singh, J.P., Kaur, A., Singh, N., 2018. Phenolic compounds as beneficial phytochemicals in pomegranate (Punica granatum L.) peel: a review. Food Chem. 261, 75
86. Available from: https://doi.org/10.1016/j.foodchem.2018.04.039.

278

Valorization of Fruit Processing By-products

Singleton, V.L., Orthofer, R., Lamuela-Ravento´s, R.M., 1999. [14] Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent. Methods in Enzymology. Academic Press, pp. 152
178. Sinha, K., Saha, P. Das, Datta, S., 2012. Response surface optimization and artificial neural network modeling of microwave assisted natural dye extraction from pomegranate rind. Ind. Crops Prod. 37, 408
414. Available from: https://doi.org/10.1016/j.indcrop.2011.12.032. Sood, A., Gupta, M., 2015. Extraction process optimization for bioactive compounds in pomegranate peel. Food Biosci. 12, 100
106. Available from: https://doi.org/10.1016/j.fbio.2015.09.004. Spigno, G., Tramelli, L., De Faveri, D.M., 2007. Effects of extraction time, temperature and solvent on concentration and antioxidant activity of grape marc phenolics. J. Food Eng. 81, 200
208. Su, D., Li, H., Lu, C., 2018. Microwave extraction of polyphenol from pomegranate seed. Asian J. Bot. 1, 36
46. Available from: https://doi.org/ 10.24294/.v1.i1.303. Sumere, B.R., de Souza, M.C., dos Santos, M.P., Bezerra, R.M.N., da Cunha, D.T., Martinez, J., Rostagno, M.A., 2018. Combining pressurized liquids with ultrasound to improve the extraction of phenolic compounds from pomegranate peel (Punica granatum L.). Ultrason. Sonochem. 48, 151
162. Available from: https://doi.org/10.1016/j.ultsonch.2018.05.028. Tabaraki, R., Heidarizadi, E., Benvidi, A., 2012. Optimization of ultrasonic-assisted extraction of pomegranate (Punica granatum L.) peel antioxidants by response surface methodology. Sep. Purif. Technol. 98, 16
23. Available from: https://doi.org/10.1016/j.seppur.2012.06.038. Talekar, S., Patti, A.F., Vijayraghavan, R., Arora, A., 2018. An integrated green biorefinery approach towards simultaneous recovery of pectin and polyphenols coupled with bioethanol production from waste pomegranate peels. Bioresour. Technol. 266, 322
334. Available from: https://doi. org/10.1016/j.biortech.2018.06.072. Tehranifar, A., Zarei, M., Nemati, Z., Esfandiyari, B., Vazifeshenas, M.R., 2010. Investigation of physico-chemical properties and antioxidant activity of twenty Iranian pomegranate (Punica granatum L.) cultivars. Sci. Hortic. (Amsterdam). 126, 180
185. Available from: https://doi.org/10.1016/ j.scienta.2010.07.001. Tiwari, H.C., Singh, P., Mishra, P.K., Srivastava, P., 2010. Evaluation of various techniques for extraction of natural colorants from pomegranate rindUltrasound and enzyme assisted extraction. Indian J. Fibre Text. Res. 35, 272
276. Unica, O.P., Is, G.L., Negi, P.S., Jayaprakasha, G.K., 2003. Antioxidant and antibacterial activities of punica granatum peel extracts. J. Food Sci. 68, 1473
1477. Available from: https://doi.org/10.1111/j.1365-2621.2003.tb09669.x. Verardo, V., Garcia-Salas, P., Baldi, E., Segura-Carretero, A., Fernandez-Gutierrez, A., Caboni, M.F., 2014. Pomegranate seeds as a source of nutraceutical oil naturally rich in bioactive lipids. Food Res. Int. 65, 445
452. Available from: https://doi.org/10.1016/j.foodres.2014.04.044. Wang, M., Jin, Y., Ho, C.T., 1999. Evaluation of resveratrol derivatives as potential antioxidants and identification of a reaction product of resveratrol and 2,2-diphenyl-1-picryhydrazyl radical. J. Agric. Food Chem. 47, 3974
3977. Available from: https://doi.org/10.1021/jf990382w. Wang, Q., Ma, S., Fu, B., Lee, F.S.C., Wang, X., 2004. Development of multi-stage countercurrent extraction technology for the extraction of glycyrrhizic acid (GA) from licorice (Glycyrrhiza uralensis Fisch). Biochem. Eng. J. 21, 285
292. Available from: https://doi.org/10.1016/j. bej.2004.06.002. Wang, Z., 2011. Extract of phenolics from pomegranate peels. Open Food Sci. J. 5, 17
25. Available from: https://doi.org/10.2174/ 1874256401105010017. Wang, C., Shi, L., Fan, L., Ding, Y., Zhao, S., Liu, Y., Ma, C., 2013. Optimization of extraction and enrichment of phenolics from pomegranate (Punica granatum L.) leaves. Ind. Crops Prod. 42, 587
594. Available from: https://doi.org/10.1016/j.indcrop.2012.06.031. Wang, H.Q., Zhang, L.Y., Cui, Q.F., 2018. Extraction of pomegranate peel tannins and flocculant for Microcystis aeruginosa removal. Int. J. Environ. Sci. Technol. 15, 2713
2718. Available from: https://doi.org/10.1007/s13762-018-1771-2. Wang, L., Martins-Green, M., 2014. Pomegranate and its components as alternative treatment for prostate cancer. Int. J. Mol. Sci. 15, 14949
14966. Wei, D.S., Hossain, M., Saleh, Z.S., 2007. Separation of polyphenolics and sugar by ultrafiltration: effects of operating conditions on fouling and diafiltration. In: XXIII International Congress on Electronics, Electrical Engineering and Computing CESSE, 2007 34, pp. 349
356. Wissam, Z., Abdelwahed, W., 2012. Effective extraction of polyphenols and proanthocyanidins from Pomegranate’s peel. Int. J. Pharm. Pharm. Sci. 4, 675
682. Wong, W.H., Lee, W.X., Ramanan, R.N., Tee, L.H., Kong, K.W., Galanakis, C.M., et al., 2015. Two level half factorial design for the extraction of phenolics, flavonoids and antioxidants recovery from palm kernel by-product. Ind. Crops Prod. 63, 238
248. Available from: https://doi.org/ 10.1016/j.indcrop.2014.09.049. Xi, J., He, L., Yan, L.G., 2017. Continuous extraction of phenolic compounds from pomegranate peel using high voltage electrical discharge. Food Chem. 230, 354
361. Available from: https://doi.org/10.1016/j.foodchem.2017.03.072. Xi, J., Yan, L., 2017. Optimization of pressure-enhanced solid-liquid extraction of flavonoids from Flos Sophorae and evaluation of their antioxidant activity. Sep. Purif. Technol. 175, 170
176. Available from: https://doi.org/10.1016/j.seppur.2016.10.013. Xie, Z., Liu, X., Chen, Y., Wang, L., 2009. Pilot-scale multi-stage countercurrent extraction of scutellarein from Erigeron breviscapus (Vant.) HandMazz. Sep. Sci. Technol. 44, 1250
1260. Available from: https://doi.org/10.1080/01496390902728801. Yu, C.H., Chen, J., Xiong, Y.K., Li, X.X., Dai, X.Y., Shi, C.C., 2012. Optimization of multi-stage countercurrent extraction of antioxidants from Ginkgo biloba L. leaves. Food Bioprod. Process. 90, 95
101. Available from: https://doi.org/10.1016/j.fbp.2011.05.003. Zahin, M., Aqil, F., Ahmad, I., 2010. Broad spectrum antimutagenic activity of antioxidant active fraction of Punica granatum L. peel extracts. Mutat. Res. Genet. Toxicol. Environ. Mutagen. 703, 99
107. Available from: https://doi.org/10.1016/j.mrgentox.2010.08.001.

Pomegranate Chapter | 12

279

Zhai, X., Zhu, C., Li, Y., Zhang, Y., Duan, Z., Yang, X., 2018. Optimization for pectinase-assisted extraction of polysaccharides from pomegranate peel with chemical composition and antioxidant activity. Int. J. Biol. Macromol. 109, 244
253. Available from: https://doi.org/10.1016/j. ijbiomac.2017.12.064. Zhang, L., Yang, X., Zhang, Y., Wang, L., Zhang, R., 2011. In vitro antioxidant properties of different parts of pomegranate flowers. Food Bioprod. Process. 89, 234
240. Available from: https://doi.org/10.1016/j.fbp.2010.04.007. Zhang, Q., Bian, Y., Shi, Y., Zheng, S., Gu, X., Zhang, D., et al., 2015. An economical and efficient technology for the extraction of resveratrol from peanut (Arachis hypogaea) sprouts by multi-stage countercurrent extraction. Food Chem. 179, 15
25. Available from: https://doi.org/10.1016/j. foodchem.2015.01.113. Zheng, X., Liu, B., Li, L., Zhu, X., 2011. Microwave-assisted extraction and antioxidant activity of total phenolic compounds from pomegranate peel. J. Med. Plants Res. 5, 1004
1011. Zhu, C.P., Zhai, X.C., Li, L.Q., Wu, X.X., Li, B., 2015. Response surface optimization of ultrasound-assisted polysaccharides extraction from pomegranate peel. Food Chem. 177, 139
146. Available from: https://doi.org/10.1016/j.foodchem.2015.01.022. Zill-E-Huma, Vian, M.A., Fabiano-Tixier, A.S., Elmaataoui, M., Dangles, O., Chemat, F., 2011. A remarkable influence of microwave extraction: enhancement of antioxidant activity of extracted onion varieties. Food Chem. 127, 1472
1480. Available from: https://doi.org/10.1016/j. foodchem.2011.01.112. ˇ ´ c, N., Menkovi´c, N., 2018. Optimization of ultrasound-assisted extraction of polyphenolic compounds from ˇ Zivkovi´ c, J., Savikin, K., Jankovi´c, T., Cuji´ pomegranate peel using response surface methodology. Sep. Purif. Technol. 194, 40
47. Available from: https://doi.org/10.1016/j. seppur.2017.11.032.

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Chapter 13

Strawberry Isidoro Garcı´a-Garcı´a1, M. Carmen Garcı´a-Parrilla2, Ines M. Santos-Duen˜as1, Albert Mas3 and Ana M. Can˜ete-Rodrı´guez1 1

Departamento de Quı´mica Inorga´nica e Ingenierı´a Quı´mica, Facultad de Ciencias, Universidad de Co´rdoba, Co´rdoba, Espan˜a, 2Departamento de Nutricio´n y Bromatologı´a, Toxicologı´a y Medicina Legal, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain, 3Departamento de Bioquı´mica i Biotecnologı´a, Facultad de Enologı´a, Universitat Rovira i Virgili, Tarragona, Espan˜a

Chapter Outline 13.1 Introduction 13.2 Development of new products 13.3 Using strawberries to obtain fermented products 13.3.1 Process development and quality control 13.3.2 Biotransformation of strawberry pure´e into wine and vinegar

13.1

281 285 287 287

13.4 Conclusions Acknowledgments References Further reading

296 296 297 300

288

Introduction

The strawberry plant is a herbaceous horticultural species; however, it is ligneous and perennial, and physiologically similar to deciduous fruit trees and bushes (Lo´pez Aranda, 2008). Accordingly, strawberries are usually included in fruit production statistics. The global production of fruit in general, and strawberry in particular, continues to grow at present (Fig. 13.1). While the figures for fruits and strawberry have evolved roughly in parallel, the latter have increased to a greater extent. Thus strawberries accounted for 0.38% of all fruit production in 1960 and for nearly 1% in 2016. The Asian continent is the greatest strawberry producer, with c. 45%, followed by America and Europe, each with approximately 25% (Fig. 13.2). As can be seen from Fig. 13.3, Spain is the third greatest producing country despite its small size relative to the other top producers. In fact, Spain is the leading producing country in Europe, with nearly 22% of all strawberry production on the continent (Fig. 13.4). Also, a single province (Huelva, Andalusia) accounts for 97% of the overall Spanish production (MAPA). The steady increase in fruit and strawberry production can be ascribed largely to the high nutritional value of the fruit. As can be seen from Table 13.1, strawberry contains essential nutrients and healthy phytochemicals (Pe´rez Rubio and Sanz Martı´nez, 2008; Giampieri et al., 2012; Toma´s Barbera´n, 2008; Basu et al., 2014), especially important among which are vitamin C and polyphenols, which possess antioxidant properties. The latter (flavonoids, easily hydrolyzed tannins and simple phenols, mainly) are probably the main sources of such properties and of other beneficial effects of strawberries. Although the alleged composition-related benefits of this fruit necessitate further research before they can be categorically ascertained (Clifford, 2000), strawberries have been ascribed favorable effects against oxidative stress, some tumors, type 2 diabetes, obesity, and cardiovascular and neurodegenerative diseases (Giampieri et al., 2012; Toma´s Barbera´n, 2008). The strawberry is seemingly thus a highly beneficial food under increasing demand (see Fig. 13.1). However, it is also highly perishable—even more than most other fruits. In fact, the high respiration rate of harvested strawberries (50
100 mL CO2/kg/h at 20 C during the first few days after harvesting) leads to very fast deterioration (Pe´rez Rubio and Sanz Martı´nez, 2008). In addition, strawberries have a very thin skin covering a soft pulp rich in nutrients that are especially attractive to a number of microbes. As a result, their color, firmness, flavor, aroma, nutritional value, and Valorization of Fruit Processing By-products. DOI: https://doi.org/10.1016/B978-0-12-817106-6.00013-7 © 2020 Elsevier Inc. All rights reserved.

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FIGURE 13.1 Variation of the global production of fruits and strawberry since 1960. Adapted from http://www.fao.org/faostat (accessed 11.18). FIGURE 13.2 Percentage share of strawberry production by continent over the period 1994
2016. Data from FAOSTAT. http://www. fao.org/faostat (accessed 11.18).

food safety can rapidly deteriorate and fail to meet the stringent quality requirements for marketing—which in some cases are based purely on appearance or size rather than on nutritional value. These shortcomings call for very careful harvesting, and also for complex, expensive postharvest processing, to lengthen the shelf life of strawberries. For example, assuring marketability of this fruit entails careful packaging and strict control of temperature, moisture, and atmospheric conditions (viz., O2 and CO2 levels), among other variables. As a result, classification of strawberries into market-oriented categories is currently done. This includes that a part of the fruits are also classified as not-marketable and, thus, waste is inevitably produced. Waste resulting from food production usually poses serious problems. Thus although food production figures have increased markedly in recent times, so have production losses. In fact an estimated 1300 million tons of food is lost globally at the different links of the supply chain each year (Gustavsson et al., 2011; Can˜ete-Rodrı´guez et al., 2016a). This figure is far from the target of so-called “green economy” or “bioeconomy,” which aims to replace a global economy revolving around petroleum to one sensibly exploiting renewable natural resources (IFPRI, 2013).

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FIGURE 13.3 Top 10 strawberry producers in the world. FAOSTAT (November 12, 2018), http://www.fao.org/faostat (accessed 11.18).

FIGURE 13.4 Main European strawberry producers. http://www.fao.org/faostat (accessed 11.18).

Current global fruit and vegetable losses amount to nearly 50% of the whole production (Gustavsson et al., 2011). The amounts lost during the cropping, postharvesting, processing, distribution, and consumption stages differ among world regions. Losses occur largely during the production and consumption stages in developed countries, but mainly during production and processing in developing countries. This is usually the case not only with fruits and vegetables, but also with most types of foods (Gustavsson et al., 2011; Buzby, in IFPRI, 2013, p. 16).

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TABLE 13.1 Strawberry composition. Nutrient

Sugars

Minerals

Vitamins

Lipids

Amino acids

Flavonoids

Value per 100 g

Water (g)

90.95

Energy (kcal)

32

Protein (g)

0.67

Ash (g)

0.4

Carbohydrate, by difference (g)

7.68

Fiber, total dietary (g)

2

Total (g)

4.89

Fructose (g)

2.44

Glucose (dextrose) (g)

1.99

Sucrose (g)

0.47

Total (mg)

207.99

Potassium (mg)

153

Phosphorus (mg)

24

Calcium (mg)

16

Total (mg)

65.82

Vitamin C, total ascorbic acid (mg)

58.8

Choline, total (mg)

5.7

Total (g)

0.44

Fatty acids, total polyunsaturated (g)

0.155

18:2 undifferentiated (g)

0.09

18:3 undifferentiated (g)

0.065

Total (g)

0.56

Aspartic acid (g)

0.149

Glutamic acid (g)

0.098

Leucine (g)

0.034

Anthocyanidins, total (mg)

27.1

Pelargonidin (mg)

24.9

Cyanidin (mg)

1.7

Flavan-3-ols, total (mg)

4.5

(1)-Catechin (mg)

3.1

(2)-Epigallocatechin (mg)

0.8

Flavanones (mg)

0.3

Naringenin (mg)

0.3

Flavones

0

Flavonols (mg)

1.6

Quercetin (mg)

1.1

Kaempferol (mg)

0.5

Isoflavones

0

Proanthocyanidin, total (mg)

105.3

Proanthocyanidin polymers ( . 10 mers) (mg)

54.2

Proanthocyanidin 4
6 mers (mg)

23.3 (Continued )

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285

TABLE 13.1 (Continued) Nutrient

Value per 100 g

p-Hydroxybenzoic acid (i.e., gallic acid) (mg)

0.5
6.9

p-Coumaric acid (mg)

0.26
0.78

Hydrolyzable tannins

Ellagic acid (mg)

2.4
5.9

Other

Melatonin (mg)

1.38
11.26 3 1024

Citric acid (mg)

321
1240

Malic acid (mg)

100
680

Phenolic acids

Source: Adapted from U.S. Department of Agriculture, Agriculture Research Service; Cerezo, A.B., Cuevas, E., Winterhalter, P., Garcı´a-Parrilla, M.C., Troncoso, A.M., 2010. Isolation, identification, and antioxidant activity of anthocyanin compounds in Camarosa strawberry. Food Chem. 123 (3), 574
582. ´ lvarez-Ferna´ndez, M.A., Hornedo-Ortega, R., Cerezo, A.B., Troncoso, A.M., Garcı´aAvailable from: https://doi.org/10.1016/j.foodchem.2010.04.073; A Parrilla, M.C., 2014b. Effects of the strawberry (Fragaria ananassa) puree elaboration process on non-anthocyanin phenolic composition and antioxidant activity. Food Chem. 164, 104
112. Available from: https://doi.org/10.1016/j.foodchem.2014.04.116; Stu¨rtz, M., Cerezo, A.B., Cantos-Villar, E., Garcı´aParrilla, M.C., 2011. Determination of the melatonin content of different varieties of tomatoes (Lycopersicon esculentum) and strawberries (Fragaria ananassa). Food Chem. 127 (3), 1329
1334. Available from: https://doi.org/10.1016/j.foodchem.2011.01.093; Pe´rez Rubio, A.G., Sanz Martı´nez, C., 2008. Te´cnicas de post-cosecha, manejo, almacenamiento y transporte de frutos, chapter V. In: J. de Andalucı´a (Ed.), La Fresa de Huelva. Consejerı´a de Agricultura y Pesca, pp. 223
247. 84-8474-222-9 (free available book from: https://www.juntadeandalucia.es/servicios/publicaciones/detalle/54443.html).

As much as 35% of strawberry production is second-grade, 20% third-grade, and 10% waste. Whereas second-grade strawberries can to a greater or lesser extent be sold at local markets, third-grade strawberries are rapidly lost unless they can be easily converted for other uses. The proportion of rejected produce that is eventually discarded as waste depends on a number of variables. In any case, second- and third-grade fruit is usually a healthy product which is not deemed first-grade because of size or appearance and can thus end up as waste. Food waste cannot only raise environmental problems, but also results in considerable losses of labor, materials, and energy. Based on the above-described problems, the high nutritional value of strawberries and the suitability of their chemical composition, a new transformation industry has emerged in some production areas to transform strawberries that cannot be marketed as whole fruits into frozen foods, pure´es, concentrates, and other formulations for preparing a number of foods (Hudisa).

13.2

Development of new products

Because the traditional market for fruit juice and preserves is virtually saturated, the favorable chemical composition of strawberry could be used to obtain products with added economic and nutritional value including beverages and condiments, such as those already developed under several research projects funded by the Spain’s Ministry of Science and Innovation (AGL2007-66417 and AGL2010-22152). Thus partial or complete biooxidation of strawberry sugars under the controlled action of different microorganisms gives more stable products for various uses. For example, using suitable yeasts under appropriate conditions allows alcoholic beverages to be obtained, and further biotransformation of the alcohol under acetic acid bacteria (AAB) gives vinegar with excellent sensory properties and increased content of ´ beda et al., 2011b; Mas et al., 2014; Ordo´n˜ez et al., 2015; Callejo´n bioactive substances (Hidalgo et al., 2012, 2013; U et al., 2015). AAB have opened up new avenues for obtaining food derivatives. Thus their special metabolism (Deppenmeier and Ehrenreich, 2009) facilitates the oxidation of a wide range of carbohydrates and alcohols to obtain a variety of end products. One of the more interesting products is gluconic acid (GA), which, considering the many uses it has, particularly for the agrifood industry, could represent an example of a product to be obtained to optimize the use of fruit surpluses and/or wastes (Can˜ete-Rodrı´guez et al., 2016a). This is a weak, nonvolatile, biodegradable acid which is present as such and as various derivatives in many foods. The agrifood industry uses GA as a food preservative or an enhancer of sensory properties. Also the US Food and Drug Administration (USFDA) has deemed it safe for use and FAO has classified glucono-δ-lactone as an allowed additive under the “good manufacturing practices” label in fermented milk, whey protein, fresh pasta, and even infant supplements (Codex Alimentarius, 1995). GA and its derivatives act as acidity regulators and improve the sensory properties of many foods; also they have been ascribed healthy effects arising

286

Valorization of Fruit Processing By-products

from their prebiotic properties, which have a favorable impact on colon microbiota—particularly on Lactobacillus and Bifidobacteria (Can˜ete-Rodrı´guez et al., 2016a). Ever since these bacterial species were found to act on the intestine, they have been increasingly added to diet supplements; however, they are also being increasingly used in combination with prebiotic agents to facilitate their growth in the intestine. In fact the ability of these bacteria to use GA and its derivatives as substrates makes them effective prebiotic agents for intestinal microbiota. Unsurprisingly the properties of GA and its derivatives have promoted their use. Their biotransformation from new raw materials and agrifood industry has been favored instead of more expensive conventional production methods (Can˜ete-Rodrı´guez et al., 2016a). For example, strawberries were used to develop a new generation of fermented beverages in the framework of a research project (AGL2010-22152). Specifically, AAB and yeasts were used to convert strawberry surpluses into a nonalcoholic beverage with a pleasant flavor. This application is described next in greater detail to illustrate the potential advantages and difficulties encountered in converting fruit that cannot be marketed for one reason or another into new products with an increased added value. Basically, see Fig. 13.5, the beverage is obtained by mixing two base products; on one side, vinegar obtained from alcoholic and acetic fermentations of strawberries and, on the other side, the resulting product from the biooxidation of glucose contained in the fruit into GA. The primary objectives were to obtain a refreshing, alcohol-free, soft beverage with an appealing acid flavor and the sweetness of fructose contained in the raw material. The product should retain the healthy properties of the original fruit (particularly its antioxidant character) as far as possible and be appreciated by consumers seeking healthy foods or those prone to diabetes—the product has a reduced glycemic index. The presence of acetic and GAs was expected to result in a low pH and hence in better chemical and biological stability. Ultimately, the product should provide a balanced combination of the volatile acidity of acetic acid, the sweetness of fructose to counter the sourness of the acid, and the acidity of GA to improve the overall flavor and buffer the low pH.

FIGURE 13.5 A potential scheme for valorizing strawberry surpluses by developing new products.

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13.3 13.3.1

287

Using strawberries to obtain fermented products Process development and quality control

Success in using fruit surpluses to obtain fermented products requires a multidisciplinary approach to develop the sequence of steps needed and to evaluate the results. The determinations involved include: G G G

analyzing the raw material and end products for chemical composition, sensory properties, and safety; selecting and characterizing the microbes that are to effect the biotransformations needed; and the design of the process and optimizing the operating conditions.

The perishable nature of strawberries requires the use of a preliminary step for their preparation and preservation. Basically, the fruit is converted into pasteurized pure´e with a variable sugar content (30
220 g/L) that is stored refrigerated until use (Fig. 13.6). Although the concentration treatment is conducted in a low-pressure evaporator, it can affect the sensory properties of the resulting pure´e and its antioxidant properties. Therefore the efficiency of the treatment and hence the reduction in transportation costs differ with the intended use of the end product (usually yoghurt, juice, jam, or ice).

FIGURE 13.6 Production of strawberry pure´e.

288

Valorization of Fruit Processing By-products

The extent to which strawberries can deteriorate during pure´e production has been assessed by examining changes in major aroma compounds including free volatiles and sugar-bound compounds that contribute very markedly to the ´ beda et al., 2014). As shown in Fig. 13.6, strawberries are ground and subjected to aroma profile of the product (U enzyme deactivation by heating at 55 C
65 C for 2 min, filtration through sieves of 1.5 or 0.5 mm pore size, and pasteurization at 90 C for 3 min. The larger and smaller pore sizes provide pure´e with and without seeds, respectively. Overall the process reduces the concentrations of free and sugar-bound aroma compounds, the reduction amounting to about 50% for the free fraction. As expected, pasteurization causes the greatest losses (particularly of higher alcohols and ethyl esters). In this situation, the aroma of the resulting pure´e is due mainly to sugar-bound precursors in the fruit. The largest contributors to the aroma of the raw material are cinnamic acid glycosides, 2,5-dimethyl-4-hydroxy-3(2H)furanone, 1-butanol, and 2,5-dimethyl-4-methoxi-3(2H)-furanone, all of which are typically present at concentrations in the milligram-per-liter range. Changes in nonanthocyanin phenols and antioxidant capacity during strawberry pure´e (SP) production have also ´ lvarez-Ferna´ndez et al. (2014b) studied the presence of and changes in 32 phenolic compounds been examined. Thus A in pure´e with and without seeds and found the end products to retain the phenolic profile and in vitro antioxidant activity of the starting material. Grinding and filtering seemingly failed to break seeds and release their contents. Consequently, the thermal treatment involved in the conversion of strawberries into SP has the expected effect and reduces the concentrations of free volatiles substantially contributing to the final aroma; even so the pure´e has a substantial aroma potential due to sugar-bound compounds. Also because the pure´e retains the phenolic profile and antioxidant capacity of the original fruit, it possesses a nutritional quality and can be further converted into other products with a potentially greater added value.

13.3.2

Biotransformation of strawberry pure´e into wine and vinegar

13.3.2.1 Alcoholic fermentation The vinegar production involves two sequential transformations, namely, alcoholic fermentation and subsequent acetification of the resulting wine. Alcoholic fermentation has been extensively studied in microbiological, chemical, and technological terms, particularly in relation to wine and beer production. Most alcoholic fermentation processes are driven by yeasts of the genus Saccharomyces, especially the species Saccharomyces cerevisiae or Saccharomyces bayanus (Ribe´reau-Gayon et al., 2000). Although commercial Saccharomyces inocula for alcoholic fermentation are commercially available, native strawberry yeasts are more closely adapted to the properties of the fruit and hence are usually preferred. Hidalgo et al. (2013) found the choice for alcoholic fermentation of fresh strawberries ground under sterile laboratory conditions to be an S. cerevisiae strain deposited under code CECT 13057 in the Spanish Type Culture Collection. Because unconcentrated SP contains a low concentration of sugars (approximately 5%), the highest alcoholic strength it affords is only 2%
3% (v/v) and the acetic strength (w/v) of the vinegar even lower. Also such a low sugar concentration hinders the development of biotransformations and decreases the stability of the resulting products. Although pure´e concentrates might in theory help avoid this shortcoming, their high viscosity makes them cumbersome to process in bioreactors. One effective alternative is the addition of rectified concentrates of grape musts, which are very rich in reducing sugars, glucose and fructose, and thus provide a suitable medium in terms of sugar composition and fluidity for alcoholic fermentation and subsequent acetification. Fig. 13.7 shows selected results for the alcoholic fermentation of sucrose-enriched SP in the presence of S. cerevisiae CECT 13057. Runs were conducted at 23 C in 8 L glass vessels filled to a volume of 6 L (Hidalgo et al., 2013) or in 5 L Biostat reactors containing 3.6 L of fermentation medium at 29 C with stirring at 250 rpm (results pending publication). The results of these tests confirm that SP can be easily converted into strawberry wine without much difficulty. Other fed-batch runs revealed that the fermentation reactor allowed operation over a number of cycles with no apparent carryover or loss of activity. One other aspect of alcoholic fermentation to be considered is the changes in phenolic composition. As noted ear´ lvarez-Ferna´ndez et al. (2015) lier, phenols are largely responsible for the antioxidant properties of strawberries. A examined changes in 66 nonanthocyanin polyphenols to develop a linear discriminant analysis method based on 19 of them with a view to establishing whether a given sample was withdrawn at the beginning or end of alcoholic fermentation. The most salient changes included an increase in the levels of compounds such as homovanillic acid and p-hydroxybenzoic acid, and a decrease in galloyl
bis-hexahydroxydiphenoy glucose.

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289

FIGURE 13.7 An example of alcoholic fermentation of strawberry pure´e with batch cultures in static and stirred fermentation reactors.

In any case, changes in antioxidant capacity cannot be explained solely in terms of overall changes in nonanthocyanins as they are also dependent on various other compounds including anthocyanins. Hornedo-Ortega et al. (2016a) examined changes in the anthocyanin profile of strawberries upon alcoholic fermentation and identified 11 compounds, the most significant of which in quantitative terms were pelargonidin 3-glucoside, pelargonidin 3-rutinoside, and cyanidin 3-glucoside. The first and last of these three underwent the greatest changes (a reduction of about 45%). By contrast, the overall antioxidant capacity of SP typically changes insubstantially (approximately 15% at most) by effect of ´ lvarez-Ferna´ndez et al., 2015; Hornedo-Ortega et al., 2016a). alcoholic fermentation (A

13.3.2.2 Acetification Strawberry wine can be converted into vinegar by biooxidation with AAB. Vinegar (particularly wine vinegar, which is the vinegar most widely produced from a fruit) is typically obtained by using a complex AAB microbiota comprising the microbes best adapting to the conditions of the particular acetification medium (Baena-Ruano et al., 2010; Garcı´aGarcı´a et al., 2007, 2009; Maestre et al., 2008; Solieri and Giudici, 2009; Jime´nez-Hornero et al., 2009a,b,c; BaenaRuano et al., 2010a,b; Vegas et al., 2010; Mamlouk and Gullo, 2013; Hidalgo et al., 2013; Vegas et al., 2013, Gullo et al., 2014; Santos-Duen˜as et al., 2015). This procedure has proved viable and stable enough for the industrial production of vinegar. The highly variable and extremely acidic conditions of the process require bacteria capable of simultaneously or sequentially acting at the different stages of the typical fed-batch operation cycles involved. The widespread use of mixed cultures for this purpose is a result of the difficulty of culturing AAB in the laboratory, outside their natural environment (Gullo et al., 2013, 2014). In fact some microbes present and fully active in natural and industrial environments are very difficult or even impossible to culture under typical laboratory conditions (Torija et al., 2010). This has precluded a comprehensive understanding of the phenomena occurring during acetification by microbial mixtures. There have been attempts using pure AAB cultures to facilitate better control of the process and the obtainment of products of improved quality allegedly associated to the activity of specific microorganisms (Gullo et al., 2009; Hidalgo et al., 2010, 2013). In any case, a sound knowledge of the composition and activity of acetification microbes could be of help to optimize the process and to select appropriate pure cultures replacing the complex microbiota currently used. Hidalgo et al. (2013) studied the acetification of strawberry wine under spontaneous conditions. They identified various AAB and found an Acetobacter malorum strain (CECT 7742) that was later sequence by Sa´inz et al. (2016b) to

290

Valorization of Fruit Processing By-products

provide the best results. The bacteria were identified from colonies formed in dish cultures grown on GY medium (10% glucose, 1% yeast extract, and 1.5% agar). A number of bacteria present during the acetification process do not grow in this medium, however (Torija et al., 2010); for this reason, Valera et al. (2015) used culture-independent techniques to obtain a broader view of the AAB microbiota present. Thus they added pure cultures of A. malorum CECT 7742 to strawberry wine and found it remained the dominant strain after acetification of the wine; however, it was displaced by other genera and species when the process was conducted in some types of vessel. Specifically, only A. malorum was detected throughout in glass vessels. On the other hand, Gluconoacetobacter saccharivorans and G. xylinus prevailed in oak and cherry wood casks, respectively. Therefore the acetification environment may affect some influential variables such as oxygen availability and hence lead to changes in microbial prevalence. The switch in dominant genera from Acetobacter to Gluconoacetobacter during the process may have resulted from their differing in tolerance to a high acidity (Hidalgo et al., 2013). Fig. 13.8 illustrates the process as conducted in the batch mode, using a pure inoculum of A. malorum with 6 L of strawberry wine in a 8 L vessel at room temperature (23 C 6 3 C). The figure also shows the process in the semicontinuous fed-batch mode as conducted in a 5 L Biostat reactor filled to about 4 L at 30 C with continuous aeration, the reactor being unloaded by about 50% after each cycle and the remaining inoculum being left in it to operate in the next cycle (unpublished results). The figure shows the first seven fed-batch cycles with an initial culture obtained from an 8 L Frings acetifier operating in a steady manner to produce alcohol vinegar. Based on the results, the process was efficient in both the semicontinuous fed-batch (Can˜ete-Rodrı´guez et al., 2012a) and the batch mode. Batch operation required preparing a separate inoculum for each run, which was difficult for the above-described reasons; also the bacteria required some time to adjust to the medium after loading (about 10 days in the figure). On the other hand, fed-batch operation with the above-described initial inoculum required 50 h for the microbiota to adjust to the medium and acquire oxidative capacity; then the process developed faster until its rate eventually leveled off. Based on these results, strawberry vinegar could be produced on an industrial scale similarly to vinegar from wine and other raw materials. Using the semicontinuous fed-batch mode in a more or less automated manner with aeration and a controlled temperature makes the process much more productive than batchwise operation. The presence or absence of aeration can influence the sensory properties of the end product through the loss of volatiles with continuous aeration—a problem

FIGURE 13.8 An example of acetification of strawberry wine with static batch cultures and with aerated, stirred semicontinuous fed-batch reactors. Adapted from Hidalgo, C., Torija, M.J., Mas, A., Mateo, E. 2013. Effect of inoculation on strawberry fermentation and acetification processes using native strains of yeast and acetic acid bacteria. Food Microbiol. 34 (1), 88
94. Available from: https://doi.org/10.1016/j.fm.2012.11.019.

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291

that can be minimized by using volatile condensers and absorption towers—and an increased availability of oxygen for ´ beda et al., 2011a). the biotransformations and chemical reactions involved (U Strawberry wine can undergo major changes in chemical composition during acetification, particularly as regards ´ beda et al., 2011a, 2013; Hornedo-Ortega et al., 2017). In fact, these compounds such as volatiles and polyphenols (U ´ beda et al. (2011a) examined compounds influence the sensory, nutritional, and safety properties of the end products. U changes in the volatiles acetaldehyde, methyl acetate, ethyl acetate, methanol, 1-propanol, isobutanol, isoamyl acetate, 2-methyl-1-butanol, and 3-methyl-1-butanol during the batch acetification of strawberry wine to a final acidity of about 5% (w/v) as acetic acid, as well as the influence of using a glass vessel or a wood cask for the process. The previous compounds, alongside volatile acids formed from higher alcohols—which are present in large amounts in vinegar—can have a direct or indirect impact on aroma. Although the outcome depended on the type of acetification vessel used, the concentrations of the target compounds invariably decreased during the process—by exception, those of acetaldehyde, methyl acetate, and ethyl acetate exhibited the opposite trend. These changes are difficult to explain and are probably associated with biological activity in AAB, to spontaneous chemical reactions, as well as to volatile losses through evaporation—which can be expected to occur to a greater extent with active aeration of the medium. The increase in the aldehyde and the two esters is consistent with the fact that the former is an intermediate in the biotransformation of ethanol into acetic acid, so it can be oxidized more or less rapidly depending on oxygen availability in the medium. On the other hand, formation of the esters can be expected to have increased with increasing availability of acetate in a medium containing methanol and, obviously, ethanol. These esters are welcome because they are less toxic than the alcohols needed for their synthesis—the resulting vinegar contained less than 50% the methanol amount present in the starting wine. Although changes in volatiles were strongly dependent on the way acetification was conducted, their concentrations were reduced in the process, which is consistent with the results for vinegar from other substrates such as wine (Valero et al., 2005; Baena-Ruano et al., 2010). Acetification also reduces the concentrations of precursors of hazardous compounds. Thus studies on the evolution ´ lvarezof amino acids, ammonium, and urea during acetification of wine (Valero et al., 2005; Maestre et al., 2008; A Ca´liz et al., 2012, 2014) have revealed that the process reduces the content of urea, which, together with ethanol, can form carcinogenic ethyl carbamate. Changes in antioxidant capacity, total phenols, and anthocyanin monomers by effect of acetification in the batch ´ beda et al., 2013). Overall acetification reduced all these variables, but particularly the mode have also been studied (U total content of monomeric anthocyanins—possibly by oxidation and polymerization to other phenols. In any case the final antioxidant activity was well above that of various commercial types of vinegar. Therefore strawberry vinegar may be deemed a healthy product if antioxidant activity is unequivocally shown to be related to improved health. Since anthocyanin contents have been associated with bioactivity (Basu et al., 2014) and color, and, according to Clifford (2000), anthocyanins are unstable, especially when the fruit matrix containing them is disrupted during processing, the anthocyanin composition of strawberry can be highly influential. Hornedo-Ortega et al. (2017) acetified strawberry wine in efficiently stirred and aerated fermentation reactors. They found the contents of anthocyanins to decrease upon fermentation to strawberry wine and its subsequent acetification to vinegar. Thus fermentation reduced the initial anthocyanin content by 19% and acetification by a further 72%. As expected, the color changed from red to orange. Such a massive reduction in anthocyanin content may have resulted from strong aeration in the fermentation reactor. Based on these results, some of the productivity and the acetification rate may have to be sacrificed in order to obtain a particular phenolic profile.

13.3.2.3 Biotransformation of strawberry pure´e into a fermented product containing gluconic acid When the primary goal is the industrial production of GA, in practice it is more cost-effective to obtain it biotechnologically than by chemical means (specifically, by using appropriate fungi). However, the biotechnological process requires careful adjustment of pH, which should never fall below 4.5 in order to avoid the formation of citric acid (Ramachandran et al., 2006). Also ensuring an adequate supply of oxygen can be difficult with fungal mycelium cultures and these microbes produce mycotoxins that may detract from food safety. For these reasons AAB tend to be preferred (Can˜ete-Rodrı´guez et al., 2012b; Garcı´a-Garcı´a et al., 2017). AAB have the ability to partially oxidize a large variety of carbohydrates to acids, aldehydes, and ketones; depending on the particular operating conditions, these products may accumulate in the medium temporarily or permanently. The oxidative capacity of AAB could be used for the biotransformation of SP into GA, even selectively (i.e., without using other carbohydrates such as fructose). Gluconobacter spp. are especially useful for this purpose. Fig. 13.9

292

Valorization of Fruit Processing By-products

summarizes the reactions involved (Garcı´a-Garcı´a et al., 2017). AAB can oxidize glucose to GA in both the periplasm and cytoplasm depending on various environmental variables. Glucose is rapidly oxidized in the AAB periplam, the resulting GA can be further oxidized to ketogluconates. This is a survival strategy involving the synthesis of compounds that are more difficult to use by other microbes and also a way of considerably reducing the pH of the medium (Deppeenmeier and Ehrenreich, 2009). On the other hand, cytoplasmic glucose is oxidized to gluconate mainly to facilitate uptake of the product through the pentose phosphate pathway (Prust et al., 2005). Depending, in decreasing importance, on pH, the initial concentration of glucose in the medium, that of CaCO3, and the amount of dissolved oxygen, either periplasmic or cytoplasmic glucose is oxidized preferentially over the other (Garcı´a-Garcı´a et al., 2017). Thus pH 2.5
3.5 and high initial glucose concentrations (up to about 90 g/L) favor the formation of GA and inhibit its subsequent oxidation to keto acids—which is assisted by the presence of CaCO3 in the medium. Dissolved oxygen levels of about 20% also favor the formation of GA. In any case each AAB species may behave differently depending on the particular culture medium where it develops (Sa´inz et al., 2016a,b). Sa´inz et al. (2016a) studied 16 strains of the genus Gluconobacter and three of Acetobacter in order to identify those using no fructose and producing GA that would resist further oxidation to ketogluconates in various media, including SP. Based on the results obtained with batch cultures in an orbital shaker at 125 rpm at 28 C, they concluded that G. japonicus CECT 8483 and G. oxydans Po5—which was previously investigated by Vegas et al. (2010)—were the most efficient species in selectively converting D-glucose to GA without altering the fructose content of the pure´e. The results for G. japonicus were consistent with those of preliminary tests conducted by the same and other authors (Sa´inz et al., 2012; Can˜ete-Rodrı´guez et al., 2012a). Sa´inz et al. (2016b) performed a similar test, albeit

FIGURE 13.9 Glucose metabolism in Gluconobacter. GDH, pyrroloquinoline quinone (PQQ)-dependent D-glucose dehydrogenase in cytoplasmic membrane (EC 1.1.5.2); GDH-NADP, nicotinamide adenine dinucleotide phosphate (NADP)-dependent D-glucose dehydrogenase in cytoplasm (EC 1.1.1.47); GADH, flavin adenine dinucleotide (FAD)-dependent D-gluconate 2-dehydrogenase (EC 1.1.99.3); 2KGADH, FAD-dependent 2-keto-D-gluconate dehydrogenase (EC 1.1.99.4); GA5DH, PQQ-dependent D-gluconate 5-dehydrogenase in cytoplasmic membrane; GA5DH-NADP, NADPdependent D-gluconate 5-dehydrogenase in cytoplasm (EC 1.1.1.69); 2KGR, 2-keto-D-gluconate reductase (EC 1.1.99.3); 5KGR, 5-keto-D-gluconate reductase (EC 1.1.1.69); PPP, pentose phosphate pathway; EDP, Entner
Doudoroff pathway. Adapted from Garcı´a-Garcı´a, I., Can˜ete-Rodrı´guez, A., Santos-Duen˜as, I., Jime´nez-Hornero, J., Ehrenreich, A., Liebl, W., et al., 2017. Biotechnologically relevant features of gluconic acid production by acetic acid bacteria. Acetic Acid Bacteria 6 (1), 7
12. Available from: https://doi.org/10.4081/aab.2017.6458.

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with a synthetic medium, to examine the behavior of G. japonicus CECT 8483, G. japonicus NBRC 3271, G. oxydans Po5, G. oxydans 621H, A. malorum CECT 7742, and A. malorum NBRC 108912, and found G. oxydans Po5 and G. oxydans 621H to be the best performers. Based on these results and on those of the previous tests, the composition of the culture medium influences the product profile obtained. Can˜ete-Rodrı´guez et al. (2015, 2016b,c) assessed the practical viability of bioconverting SP in the presence of G. japonicus under controlled operating conditions in a laboratory-scale bioreactor. The variables examined included the inoculum preparation procedure, nature and conditioning of the culture medium, operating conditions, and various aspects of the process. Because the biotransformation was to be effected by a pure or dominant culture of Gluconobacter, the inoculum preparation and pure´e conditioning procedures were especially influential. Also, because the raw material was pasteurized SP, it might need some additional processing (e.g., thermal sterilization) prior to receiving the G. japonicus inoculum. To what extent the inoculum should be conditioned and how rapidly it would act were additional influential variables. Can˜ete-Rodrı´guez et al. (2015) found G. japonicus CECT 8443 to efficiently convert glucose in pasteurized SP into GA while preserving the fructose content of the substrate. Although unwanted microbes are typically present in industrially pasteurized fruit pure´es (yeasts, mainly), in this case, the pure´e required no additional thermal or chemical treatment to prevent growth of other microorganisms. To obtain this result, preparing the inoculum in two steps, while not strictly needed, led to better results. The first step involved allowing the selected strain to grow on glucose, yeast extract, peptone (GYP) medium for 24 h, and the second adding an identical volume of sterilized SP and allowing incubation for a further 24 h before the inoculum
pure´e combination was added to the fermentation reactor, loaded with pasteurized pure´e. This procedure provided highly active G. japonicus adapted to the working medium that started producing GA immediately, with no lag phase. This was especially important because the fermentation reactor contained no sterilized pure´e, in order to preserve the sensory and nutritional properties of the medium, but a pasteurized one, so glucose had to be quickly converted into GA before yeasts in the medium were reactivated. Because no individual colony could be recovered from dish cultures, yeasts in the medium had to be determined by direct counting of total cell numbers under a light microscope. This does not mean that the yeasts were definitely unviable, but rather that industrial pasteurization might have altered them to an extent precluding dish culturing at the time but not once the growing conditions were favorable again—which was eventually the case as shown below. A similar behavior was previously observed in other microorganisms (McDougald et al., 1998). Fig. 13.10, adapted from Can˜ete-Rodrı´guez et al. (2015), shows selected results of the tests. As can be seen, glucose was depleted within 20 h, largely through conversion into GA and with no apparent uptake of fructose. Blank tests with no G. japonicus inoculum in the fermentation medium revealed reactivation of yeasts, and their use of both glucose and fructose, after about 25 h. Tests were performed with no pH control when in fact pH changes may reflect the evolution of the process (as can be seen in Fig. 13.10, pH changed in parallel with sugar concentrations). These results testify to the feasibility of the target biotransformation. In the tests using a bacterial inoculum, the process was stopped when glucose in the medium was depleted in order to avoid the uptake of fructose and GA. It would therefore have been interesting to assess the stability of the resulting GA if the process had not been stopped or if alternative operating conditions had been used. Can˜ete-Rodrı´guez et al. (2016c) found GA stability to depend on the initial concentration of glucose in the medium. They used standard SP containing an approximate sugar concentration of 34 g/L (about 50% glucose and 50% fructose) or enriched pure´e (ESP) containing a 135
140 g/L concentration of a 1:1 glucose/fructose mixture. As can be seen from Fig. 13.11, only GA formed with the higher initial sugar concentration was stable, its stability probably resulting from the inhibitory effect of the acid itself and the low final pH (Can˜ete-Rodrı´guez et al., 2016c). Also total acidity and pH leveled off once the peak concentration of GA was reached. On the other hand, the variation of total acidity and pH with SP suggests that GA was initially converted into ketogluconates—hence the constancy in the previous two variables—and that the resulting keto acids were used as metabolic substrates for the bacteria (see Fig. 13.9), thereby leading to a decreased total acidity and an increased pH. Fructose also evolved differently. Although this sugar was used largely by yeasts present in the medium (Can˜eteRodrı´guez et al., 2015, 2016c), its kinetics of disappearance differed. Thus the stronger conditions reached with ESP had an adverse impact on the fructose uptake rate. In any case these results confirm the best conditions for obtaining gluconic fermentates from SP. Thus if the raw material has a low sugar content, the biotransformation process should be stopped as soon as glucose has been depleted in order to prevent GA from being converted into other products and eventually used by the bacteria. On the other hand, if the pure´e can be enriched with sugars, the resulting GA will be stable; however, the end product will differ in sweetness by the effect of fructose being consumed to an extent dependent on the length of the fermentation process.

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FIGURE 13.10 Gluconic acid production from strawberry pure´e with an adapted culture of G. japonicus as inoculum. Adapted from Can˜eteRodrı´guez, A.M., Santos-Duen˜as, I.M., Torija-Martinez, M.J., Mas, A., Jime´nez-Hornero, J.E., Garcı´a-Garcı´a, I., 2015. Preparation of a pure inoculum of acetic acid bacteria for the selective conversion of glucose in strawberry puree into gluconic acid. Food Bioprod. Process. 96, 35
42. Available from: https://doi.org/10.1016/j.fbp.2015.06.005.

In summary, preserving the nutritional properties of a natural substrate as far as possible requires examining the potential effect of operational variables on the target conversion and finding the optimum balance to fulfill the intended goal. With SP this is indeed possible though not always simple. Thus determining the specific growth rate μ of the bacteria is made difficult by the complex physicochemical properties of the medium (e.g., the presence of large amounts of suspended solids); also bacteria can be hardly cultured in dishes. This requires using indirect determination methods such as that devised by Can˜ete-Rodrı´guez et al. (2016b), which estimates μ without the need to establish the concentration of G. japonicus cells in the medium. This method is also applicable to other Gluconobacter species or even culture media. As noted in previous sections for alcoholic and acetic fermentations, it is important to assess the effects of the gluconic conversion in SP on certain compounds with a potential impact on the sensory, bioactive, and nutritional properties ´ lvarez-Ferna´ndez et al., 2014a; Hornedo-Ortega et al., 2016a). of the end product (particularly phenolic compounds) (A Specifically, samples from the above-described biotransformation tests on SP (Can˜ete-Rodrı´guez et al., 2015, 2016a,b, ´ lvarez-Ferna´ndez et al., 2014a) five of which were for the first c) were found to contain 43 nonanthocyanin phenols (A time identified in the pure´e, namely, monogalloyl diglucose, 5-hydroxy feruroyl hexose, dihydrokaempferol hexoside, kaempferol neohesperidoside, and (2)-chicoric acid. The biotransformation hardly altered the original profile of these compounds. Also, the antioxidant capacity of the end product remained virtually identical. A similar analysis of the anthocyanin phenol profile allowed Hornedo-Ortega et al. (2016a) to identify 11 compounds that exhibited little change, and to find that the antioxidant capacity of the end product exceeded that observed after alcoholic fermentation. Finally, it is worth commenting on the composition and changes in amino acids and biogenic amines by effect of the biotransformation (Ordo´n˜ez et al., 2015, 2017). The amino acid content of the end product is important because amino acids contribute to its sensory properties; also some amino acids can be converted into biogenic amines by decarboxylation. The presence and formation of biogenic amines in foods (particularly fermented foods) has aroused much interest owing to the toxic nature of some (Brink et al., 1990). However, Ordo´n˜ez et al. (2015, 2017) detected no biogenic amines with various AAB strains under different operating conditions. Also the amino acid profile changed but the total amino acid content did not. Profile differences were ascribed to differences among strains, samples, or even end products. In any case differences in amino acid content seemingly had little effect on the nutritional potential of the end product and, especially, its safety—which was not compromised thanks to the absence of biogenic amines.

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FIGURE 13.11 Influence of the initial glucose concentration on gluconic acid production from strawberry pure´e with an adapted culture of G. japonicus as inoculum. Adapted from Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Jime´nez-Hornero, J.E., Torija-Martinez, M.J., Mas, A., Garcı´aGarcı´a, I., 2016c. Revalorization of strawberry surpluses by bio-transforming its glucose content into gluconic acid. Food Bioprod. Process. 99, 188
196. Available from: https://doi.org/10.1016/j.fbp.2016.05.005.

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13.3.2.4 Strawberry beverage storage The gluconic fermentate and strawberry vinegar can be mixed in variable proportions to obtain new products including ´ lvarezbeverages and condiments. To assess their storage stability, some authors have examined changes in phenols (A Ferna´ndez et al., 2016; Hornedo-Ortega et al., 2016b) and volatile compounds (Morales et al., 2017) over periods of up to 90 days under ambient and refrigerated conditions. For example, pasteurized samples consisting of a mixture of gluconic fermentate and about 1% of strawberry vinegar were analyzed for 64 nonanthocyanin phenols, antioxidant capac´ lvarez-Ferna´ndez ity, and sensory properties after different times and under different thermal storage conditions (A et al., 2016). The composition of nonanthocyanins underwent no appreciable change after 15 days at room temperature or 30 days at 4 C; however, longer storage times caused some changes such as increased levels of protocatechuic acid and decreased levels of condensed tannins. Probably as a result of these changes, the antioxidant capacity increased over the first 60 days of storage and then decreased. A panel of tasters distinguished samples stored at a variable temperature for 60 days, but not those stored for only 30 days. It was therefore concluded that the product should not be stored for more than 60 days under refrigeration or 30 days at ambient temperature. As expected, similar tests aimed at assessing the effect of storage on anthocyanin compounds and color (HornedoOrtega et al., 2016b) confirmed that refrigeration allowed storage for longer times (60 days with no appreciable change). Because volatile compounds are also influential on sensory properties, about 50 of them were analyzed for changes during storage. The concentrations of all target compounds increased to a similar extent over the first 60 days, but γ-decalactone, acetoin, dimethyl carbonate, hexanoic acid, and 3-methylbutanoic acid exhibited especially marked increases. From 60 to 180 days, the total concentration of volatiles decreased by effect, mainly of the decrease in γ-decalactone, acetoin, and isovaleric acid. Four of the compounds were seemingly useful as indicators of product deterioration through storage, three of them (2-phenylethyl acetate, decanoic acid, and γ-decalactone) decreasing and the fourth (furfural, which is associated with enzymatic browning in fruit juice) increasing with increasing storage time. An overall analysis of the results showed that, as expected, the most marked changes in volatile profile occurred in the samples stored at room temperature, so refrigerated storage was advisable.

13.4

Conclusions

As with other fruits, strawberry surpluses can be used to obtain new products exploiting the rich chemical composition of this fruit. Such a composition, which can be further enriched by the addition of sugars, for example, makes strawberry an excellent culture medium for a number of microorganisms and fermentation an effective choice for developing healthy, stable foods with an increased added value. Because of the high perishability of strawberry, fluctuations in seasonal markets, and occasionally too stringent quality criteria, massive strawberry surpluses are generated each year that can have a strong environmental impact as waste and cause substantial losses in labor, materials, and energy, thus having seriously adverse social and economic effects on producing areas. As shown here, developing new products is usually complicated. With SP, however, it is quite feasible. Thus variably concentrated commercial SP can be used to obtain vinegar by a combination of alcoholic and acetic fermentation. Strawberry vinegar is appealing not only by virtue of its sensory properties, but also because it retains many of the physicochemical properties of the pure´e and the compounds present in strawberry that make it a highly appreciated fruit. Also the process can be stopped after alcoholic fermentation to obtain strawberry wine. Converting glucose in SP into GA is also possible despite the natural tendency of Gluconobacter species to use the acid for further biotransformation. Also this goal can be accomplished by using little or no fructose in order to endow the resulting product with sweetness of a lower glycemic index than that resulting from glucose. This product can be used to obtain a wide range of beverages and condiments by mixing it with vinegar in variable proportions. Many of the results discussed here could also be obtained with other products and could allow the valorization of alternative fruits or agrifood by-products.

Acknowledgments The authors are grateful to Spain’s Ministry of Science and Innovation for partially funding this study through several research projects (AGL2007-66417 and AGL2010-22152), to Junta de Andalucı´a (research groups: RNM271, AGR167), and University of Co´rdoba within the framework of Programa Propio 2016 Mod.4-1 and 2018 Mod.4-2.

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References ´ lvarez-Ca´liz, C., Santos-Duen˜as, I., Can˜ete-Rodrı´guez, A., Garcı´a-Martı´nez, T., Mauricio, J., Garcı´a-Garcı´a, I., 2012. Free amino acids, urea and A ammonium ion contents for submerged wine vinegar production: influence of loading rate and air-flow rate. Acetic Acid Bacteria 1 (1), e1. Available from: https://doi.org/10.4081/aab.2012.e1. ´ lvarez-Ca´liz, C., Santos-Duen˜as, I.M., Garcı´a-Martı´nez, T., Can˜ete-Rodrı´guez, A.M., Milla´n-Pe´rez, M.C., Mauricio, J.C., et al., 2014. Effect of bioA logical ageing of wine on its nitrogen composition for producing high quality vinegar. Food Bioprod. Process. 92 (3), 291
297. Available from: https://doi.org/10.1016/j.fbp.2013.07.005. ´ lvarez-Ferna´ndez, M.A., Hornedo-Ortega, R., Cerezo, A.B., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2014a. Non-anthocyanin phenolic compounds A and antioxidant activity of beverages obtained by gluconic fermentation of strawberry. Innov. Food Sci. Emerg. Technol. 26, 469
481. Available from: https://doi.org/10.1016/j.ifset.2014.08.001. ´ lvarez-Ferna´ndez, M.A., Hornedo-Ortega, R., Cerezo, A.B., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2014b. Effects of the strawberry (Fragaria anaA nassa) puree elaboration process on non-anthocyanin phenolic composition and antioxidant activity. Food Chem. 164, 104
112. Available from: https://doi.org/10.1016/j.foodchem.2014.04.116. ´ lvarez-Ferna´ndez, M.A., Cerezo, A.B., Can˜ete-Rodrı´guez, A.M., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2015. Composition of nonanthocyanin polyA phenols in alcoholic-fermented strawberry products using LC-MS (QTRAP), high-resolution MS (UHPLC-orbitrap-MS), LC-DAD, and antioxidant activity. J. Agric. Food Chem. 63 (7), 2041
2051. Available from: https://doi.org/10.1021/jf506076n. ´ lvarez-Ferna´ndez, M.A., Hornedo-Ortega, R., Cerezo, A.B., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2016. Determination of nonanthocyanin phenolic A compounds using high resolution mass spectrometry (UHPLC-orbitrap-MS/MS) and impact of storage conditions in a beverage made from strawberry by fermentation. J. Agric. Food Chem. 64 (6), 1367
1376. Available from: https://doi.org/10.1021/acs.jafc.5b05617. Baena-Ruano, S., Jime´nez-Ot, C., Santos-Duen˜as, I.M., Cantero-Moreno, D., Barja, F., Garcı´a-Garcı´a, I., 2010. Rapid method for total, viable and non-viable acetic acid bacteria determination during acetification process. Process Biochem. 41 (5), 1160
1164. Available from: https://doi.org/ 10.1016/j.procbio.2005.12.016. ´ lvarez-Ca´liz, C., et al., 2010a. Influence of Baena-Ruano, S., Jime´nez-Ot, C., Santos-Duen˜as, I.M., Jime´nez-Hornero, J.E., Bonilla-Venceslada, J.L., A the final ethanol concentration on the acetification and production rate in the wine vinegar process. J. Chem. Technol. Biotechnol. 85 (7), 908
912. Available from: https://doi.org/10.1002/jctb.2368. Baena-Ruano, S., Santos-Duen˜as, I.M., Mauricio, J.C., Garcı´a-Garcı´a, I., 2010b. Relationship between changes in the total concentration of acetic acid bacteria and major volatile compounds during the acetic acid fermentation of white wine. J. Sci. Food Agric. 90 (15), 2675
2681. Available from: https://doi.org/10.1002/jsfa.4139. Basu, A., Nguyen, A., Betts, N.M., Lyons, T.J., 2014. Strawberry as a functional food: an evidence-based review. Crit. Rev. Food Sci. Nutr. 54 (6), 790
806. Available from: https://doi.org/10.1080/10408398.2011.608174. Brink, B.T., Damink, C., Joosten, H.M.L.J., Veld, J.H.J.H., 1990. Occurrence and formation of biologically active amines in foods. Int. J. Food Microbiol. 11 (11), 73
84. Available from: https://doi.org/10.1016/0168-1605(90)90040-C. ´ beda, C., Hidalgo, C., Mas, A., Troncoso, A.M., Morales, M.L., 2015. Changes on free amino acids during the alcoholic fermentaCallejo´n, R.M., U tion of strawberry and persimmon. Int. J. Food Sci. Technol. 50, 48
54. Available from: https://doi.org/10.1111/ijfs.12661. Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Bonilla-Venceslada, J.L., Jime´nez-Hornero, J.E., Garcı´a-Garcı´a, I., 2012a. Production of strawberry vinegar as a base product in the development of new healthy beverages. Third International Conference on Acetic Acid Bacteria Vinegar and other Products, Cordoba, Spain, April 17
20, 2012, Co´rdoba (Spain). Acetic Acid Bacteria 1 (1s), 30. Available from: https://doi.org/10.4081/ aab.2012.1s. Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Mauricio, J.C., Martı´nez-Pedrajas, C., Garcı´a-Garcı´a, I., 2012b. Submerged cultures of Gluconobacter genus in strawberry pulp for making a gluconic acid based product. An ingredient for new healthy beverages. Third International Conference on Acetic Acid Bacteria Vinegar and other Products, Cordoba, Spain, April 17
20, 2012, Co´rdoba (Spain). Acetic Acid Bacteria 1 (1s), 31. Available from: https://doi.org/10.4081/aab.2012.1s. Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Torija-Martinez, M.J., Mas, A., Jime´nez-Hornero, J.E., Garcı´a-Garcı´a, I., 2015. Preparation of a pure inoculum of acetic acid bacteria for the selective conversion of glucose in strawberry puree into gluconic acid. Food Bioprod. Process. 96, 35
42. Available from: https://doi.org/10.1016/j.fbp.2015.06.005. Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Jime´nez-Hornero, J.E., Ehrenreich, A., Liebl, W., Garcı´a-Garcı´a, I., 2016a. Gluconic acid: properties, production methods and applications: an excellent opportunity for agro-industrial by-products and waste bio-valorization. Process Biochem. 51 (12), 1891
1903. Available from: https://doi.org/10.1016/j.procbio.2016.08.028. Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Jime´nez-Hornero, J.E., Torija-Martinez, M.J., Mas, A., Garcı´a-Garcı´a, I., 2016b. An approach for estimating the maximum specific growth rate of Gluconobacter japonicus in strawberry puree without cell concentration data. Biochem. Eng. J. 105, 314
320. Available from: https://doi.org/10.1016/j.bej.2015.10.005. Can˜ete-Rodrı´guez, A.M., Santos-Duen˜as, I.M., Jime´nez-Hornero, J.E., Torija-Martinez, M.J., Mas, A., Garcı´a-Garcı´a, I., 2016c. Revalorization of strawberry surpluses by bio-transforming its glucose content into gluconic acid. Food Bioprod. Process. 99, 188
196. Available from: https://doi. org/10.1016/j.fbp.2016.05.005. Cerezo, A.B., Cuevas, E., Winterhalter, P., Garcı´a-Parrilla, M.C., Troncoso, A.M., 2010. Isolation, identification, and antioxidant activity of anthocyanin compounds in Camarosa strawberry. Food Chem. 123 (3), 574
582. Available from: https://doi.org/10.1016/j.foodchem.2010.04.073. Clifford, M.N., 2000. Anthocyanins
nature, occurrence and dietary burden. J. Sci. Food Agric. 80, 1063
1072. Available from: https://doi.org/ 10.1002/(SICI)1097-0010(20000515)80:7 , 1063::AID-JSFA605 . 3.0.CO;2-Q.

298

Valorization of Fruit Processing By-products

Codex Alimentarius, 1995. International Food Standards. General Standard for Food Additives. Codex Stan 192-1995. Adopted in 1995. Revision 1997, 1999, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018. ,http://www.fao.org/faowho-codexalimentarius/codex-texts/dbs/gsfa/en/ . (accessed 13.11.18.). Deppenmeier, U., Ehrenreich, A., 2009. Physiology of acetic acid bacteria in light of the genome sequence of Gluconobacter oxydans. J. Mol. Microbiol. Biotechnol. 16, 69
80. Available from: https://doi.org/10.1159/000142895. Garcı´a-Garcı´a, I., Cantero-Moreno, D., Jime´nez-Ot, C., Baena-Ruano, S., Jime´nez-Hornero, J., Santos-Duen˜as, I., et al., 2007. Estimating the mean acetification rate via on-line monitored changes in ethanol during a semi-continuous vinegar production cycle. J. Food Eng. 80 (2), 460
464. Available from: https://doi.org/10.1016/j.jfoodeng.2006.05.028. Garcı´a-Garcı´a, I., Santos-Duen˜as, I.M., Jime´nez-Ot, C., Jime´nez-Hornero, J.E., Bonilla-Venceslada, J.L., 2009. Vinegar engineering. In: Solieri, L., Giudici, P. (Eds.), Vinegars of the World. Springer, Italy, pp. 97
120. Available from: https://doi.org/10.1007/978-88-470-0866-3. Garcı´a-Garcı´a, I., Can˜ete-Rodrı´guez, A., Santos-Duen˜as, I., Jime´nez-Hornero, J., Ehrenreich, A., Liebl, W., et al., 2017. Biotechnologically relevant features of gluconic acid production by acetic acid bacteria. Acetic Acid Bacteria 6 (1), 7
12. Available from: https://doi.org/10.4081/ aab.2017.6458. Giampieri, F., Tulipani, S., Alvarez-Suarez, J.M., Quiles, J.L., Mezzetti, B., Battino, M., 2012. The strawberry: composition, nutritional quality, and impact on human health. Nutrition 28 (1), 9
19. Available from: https://doi.org/10.1016/j.nut.2011.08.009. Gullo, M., De Vero, L., Giudici, P., 2009. Succession of selected strains of Acetobacter pasteurianus and other acetic acid bacteria in traditional balsamic vinegar. Appl. Environ. Microbiol. 75 (8), 2585
2589. Available from: https://doi.org/10.1128/aem.02249-08. Gullo, M., Verzelloni, E., Canonico, M., 2014. Aerobic submerged fermentation by acetic acid bacteria for vinegar production: process and biotechnological aspects. Process Biochem. 49 (10), 1571
1579. Available from: https://doi.org/10.1016/j.procbio.2014.07.003. Gustavsson, J., Cederberg, C., Sonesson, U., Van Otterdijk, R., Meybeck, A., 2011. Global Food Losses and Food Waste. Food and Agriculture Organization of the United Nations, Rome. Hidalgo, C., Vegas, C., Mateo, E., Tesfaye, W., Cerezo, A.B., Callejo´n, R.M., et al., 2010. Effect of barrel design and the inoculation of Acetobacter pasteurianus in wine vinegar production. Int. J. Food Microbiol. 141 (1
2), 56
62. Available from: https://doi.org/10.1016/j. ijfoodmicro.2010.04.018. Hidalgo, C., Mateo, E., Mas, A., Torija, M.J., 2012. Identification of yeast and acetic acid bacteria isolated from the fermentation and acetification of persimmon (Diospyros kaki). Food Microbiol. 30 (1), 98
104. Available from: https://doi.org/10.1016/j.fm.2011.12.017. Hidalgo, C., Torija, M.J., Mas, A., Mateo, E., 2013. Effect of inoculation on strawberry fermentation and acetification processes using native strains of yeast and acetic acid bacteria. Food Microbiol. 34 (1), 88
94. Available from: https://doi.org/10.1016/j.fm.2012.11.019. Hornedo-Ortega, R., Krisa, S., Garcı´a-Parrilla, M.C., Richard, T., 2016a. Effects of gluconic and alcoholic fermentation on anthocyanin composition and antioxidant activity of beverages made from strawberry. LWT-Food Sci. Technol. 69, 382
389. Available from: https://doi.org/10.1016/j. lwt.2016.01.070. ´ lvarez-Ferna´ndez, M.A., Cerezo, A.B., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2016b. Influence of storage conditions on the Hornedo-Ortega, R., A anthocyanin profile and colour of an innovative beverage elaborated by gluconic fermentation of strawberry. J. Funct. Foods 23, 198
209. Available from: https://doi.org/10.1016/j.jff.2016.02.014. ´ lvarez-Ferna´ndez, M.A., Cerezo, A.B., Garcı´a-Garcı´a, I., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2017. Influence of fermentaHornedo-Ortega, R., A tion process on the anthocyanin composition of wine and vinegar elaborated from strawberry. J. Food Sci. 82 (2), 364
372. Available from: https://doi.org/10.1111/1750-3841.13624. Hudisa Desarrollo Industrial S.A. ,http://www.hudisa.es/?lang 5 enhttp://www.hudisa.es/?lang 5 en. (accessed 12.11.18.). IFPRI, 2013. 2012 Global Food Policy Report. International Food Policy Research Institute (IFPRI). 978-0-89629-553-7. ,https://doi.org/10.2499/ 9780896295537., ,http://www.ifpri.org/publication/2012-global-food-policy-report:http://www.ifpri.org/publication/2012-global-food-policyreport. (accessed 07.11.18.). Jime´nez-Hornero, J.E., Santos-Duen˜as, I.M., Garcı´a-Garcı´a, I., 2009a. Optimization of biotechnological processes. The acetic acid fermentation. Part I: The proposed model. Biochem. Eng. J. 45 (1), 1
6. Available from: https://doi.org/10.1016/j.bej.2009.01.009. Jime´nez-Hornero, J.E., Santos-Duen˜as, I.M., Garcı´a-Garcı´a, I., 2009b. Optimization of biotechnological processes. The acetic acid fermentation. Part II: practical identifiability analysis and parameter estimation. Biochem. Eng. J. 45 (1), 7
21. Available from: https://doi.org/10.1016/j. bej.2009.01.010. Jime´nez-Hornero, J.E., Santos-Duen˜as, I.M., Garcı´a-Garcı´a, I., 2009c. Optimization of biotechnological processes. The acetic acid fermentation. Part III: dynamic optimization. Biochem. Eng. J. 45 (1), 22
29. Available from: https://doi.org/10.1016/j.bej.2009.01.011. Lo´pez Aranda, J.M., 2008. El cultivo de la fresa en Huelva, chapter III. In: de Andalucı´a, J. (Ed.), La Fresa de Huelva. Consejerı´a de Agricultura y Pesca, pp. 103
172. 84-8474-222-9(free available book from: ,https://www.juntadeandalucia.es/servicios/publicaciones/detalle/54443.html.. Maestre, O., Santos-Duen˜as, I.M., Peinado, R., Jime´nez-Ot, C., Garcı´a-Garcı´a, I., Mauricio, J.C., 2008. Changes in amino acid composition during wine vinegar production in a fully automatic pilot acetator. Process Biochem. 43 (8), 803
807. Available from: https://doi.org/10.1016/j. procbio.2008.03.007. Mamlouk, D., Gullo, M., 2013. Acetic acid bacteria: physiology and carbon sources oxidation. Indian J. Microbiol. 53 (4), 377
384. Available from: https://doi.org/10.1007/s12088-013-0414-z. MAPA (Ministerio de Agricultura, Pesca y Alimentacio´n de Espan˜a). ,https://www.mapa.gob.es/es/. (accessed 07.11.18.). Mas, A., Torija, M.J., Garcı´a-Parrilla, M.C., Troncoso, A.M., 2014. Acetic acid bacteria and the production and quality of wine vinegar. Sci. World J. 2014, . Available from: https://doi.org/10.1155/2014/394671394671.

Strawberry Chapter | 13

299

McDougald, D., Rice, S.A., Weichart, D., Kjelleberg, S., 1998. Nonculturability: adaptation or debilitation? FEMS Microbiol. Ecol. 25, 1
9. Available from: https://doi.org/10.1111/j.1574-6941.1998.tb00455.x. Morales, M.L., Callejo´n, R.M., Ordo´n˜ez, J.L., Troncoso, A.M., Garcı´a-Parrilla, M.C., 2017. Comparative assessment of software for non-targeted data analysis in the study of volatile fingerprint changes during storage of a strawberry beverage. J. Chromatogr. A 1522, 70
77. Available from: https://doi.org/10.1016/j.chroma.2017.09.056. Ordo´n˜ez, J.L., Sa´inz, F., Callejo´n, R.M., Troncoso, A.M., Torija, M.J., Garcı´a-Parrilla, M.C., 2015. Impact of gluconic fermentation of strawberry using acetic acid bacteria on amino acids and biogenic amines profile. Food Chem. 178, 221
228. Available from: https://doi.org/10.1016/j. foodchem.2015.01.085. Ordo´n˜ez, J.L., Can˜ete-Rodrı´guez, A.M., Callejo´n, R.M., Santos-Duen˜as, I.M., Troncoso, A.M., Garcı´a-Garcı´a, I., et al., 2017. Effect of gluconic acid submerged fermentation of strawberry puree on amino acids and biogenic amines profile. J. Food Process. Preserv. 41 (2), e12787. Available from: https://doi.org/10.1111/jfpp.12787. Pe´rez Rubio, A.G., Sanz Martı´nez, C., 2008. Te´cnicas de post-cosecha, manejo, almacenamiento y transporte de frutos, chapter V. In: de Andalucı´a, J. (Ed.), La Fresa de Huelva. Consejerı´a de Agricultura y Pesca, pp. 223
247. , 84-8474-222-9 (Free available book from: ,https://www.juntadeandalucia.es/servicios/publicaciones/detalle/54443.html.. Prust, C., Hoffmeister, M., Liesegang, H., Wiezer, A., Fricke, W.F., Ehrenreich, A., et al., 2005. Complete genome sequence of the acetic acid bacterium Gluconobacter oxydans. Nat. Biotechnol. 23 (2), 195
200. Available from: https://doi.org/10.1038/nbt1062. Ramachandran, S., Fontanille, P., Pandey, A., Larroche, C., 2006. Gluconic acid: properties, applications and microbial production. Food Technol. Biotechnol. 44 (2), 185
195. Ribe´reau-Gayon, P., Dubourdieu, D., Done`che, B., Lonvaud, A., 2000. Handbook of Enology, vol. 1. The Microbiology of Wine and Vinifications. Wiley and Sons Ltd, West Sussex. Sa´inz, F., Mateo, E., Mas, A., Torija, M.J., 2012. Gluconic acid production in strawberry by acetic acid bacteria. Third International Conference on Acetic Acid Bacteria Vinegar and other Products, Cordoba, Spain, April 17
20, 2012, Co´rdoba (Spain). Acetic Acid Bacteria 1 (1s), 24. Available from: https://doi.org/10.4081/aab.2012.1s. Sa´inz, F., Navarro, D., Mateo, E., Torija, M.J., Mas, A., 2016a. Comparison of d-gluconic acid production in selected strains of acetic acid bacteria. Int. J. Food Microbiol. 222, 40
47. Available from: https://doi.org/10.1016/j.ijfoodmicro.2016.01.015. Sa´inz, F., Torija, M.J., Matsutani, M., Kataoka, N., Yakushi, T., Matsushita, K., et al., 2016b. Determination of dehydrogenase activities involved in D-glucose oxidation in Gluconobacter and Acetobacter strains. Front. Microbiol. 7. Available from: https://doi.org/10.3389/fmicb.2016.01358. Santos-Duen˜as, I.M., Jime´nez Hornero, J.E., Can˜ete-Rodrı´guez, A.M., Garcı´a-Garcı´a, I., 2015. Modeling and optimization of acetic acid fermentation: a polynomial-based approach. Biochem. Eng. J. 99, 35
43. Available from: https://doi.org/10.1016/j.bej.2015.03.002. Solieri, L., Giudici, P. (Eds.), 2009. Vinegars of the World. Springer, Milan, Italy. Available from: https://doi.org/10.1007/978-88-470-0866-3. Stu¨rtz, M., Cerezo, A.B., Cantos-Villar, E., Garcı´a-Parrilla, M.C., 2011. Determination of the melatonin content of different varieties of tomatoes (Lycopersicon esculentum) and strawberries (Fragaria ananassa). Food Chem. 127 (3), 1329
1334. Available from: https://doi.org/10.1016/j. foodchem.2011.01.093. Toma´s Barbera´n, F.A., 2008. Te´cnicas de post-cosecha, manejo, almacenamiento y transporte de frutos, chapter VIII. In: de Andalucı´a, J. (Ed.), La Fresa de Huelva. Consejerı´a de Agricultura y Pesca, pp. 307
333. , 84-8474-222-9 (Free available book from: ,https://www.juntadeandalucia.es/ servicios/publicaciones/detalle/54443.html.. Torija, M.J., Mateo, E., Guillamo´n, J.M., Mas, A., 2010. Identification and quantification of acetic acid bacteria in wine and vinegar by TaqManMGB probes. Food Microbiol. 27 (2), 257
265. Available from: https://doi.org/10.1016/j.fm.2009.10.001. ´ beda, C., Callejo´n, R.M., Hidalgo, C., Torija, M.J., Mas, A., Troncoso, A.M., et al., 2011a. Determination of major volatile compounds during the U production of fruit vinegars by static headspace gas chromatography-mass spectrometry method. Food Res. Int. 44 (1), 259
268. Available from: https://doi.org/10.1016/j.foodres.2010.10.025. ´ beda, C., Hidalgo, C., Torija, M.J., Mas, A., Troncoso, A.M., Morales, M.L., 2011b. Evaluation of antioxidant activity and total phenols index in U persimmon vinegars produced by different processes. LWT-Food Sci. Technol. 44 (7), 1591
1596. Available from: https://doi.org/10.1016/j. lwt.2011.03.001. ´ beda, C., Callejo´n, R.M., Hidalgo, C., Torija, M.J., Troncoso, A.M., Morales, M.L., 2013. Employment of different processes for the production of U strawberry vinegars: effects on antioxidant activity, total phenols and monomeric anthocyanins. LWT-Food Sci. Technol. 52 (2), 139
145. Available from: https://doi.org/10.1016/j.lwt.2012.04.021. ´ beda, C., Callejo´n, R.M., Troncoso, A.M., Morales, M.L., Garcı´a-Parrilla, M.C., 2014. Influence of the production process of strawberry industrial U purees on free and glycosidically bound aroma compounds. Innov. Food Sci. Emerg. Technol. 26, 381
388. Available from: https://doi.org/ 10.1016/j.ifset.2014.02.015. Valera, M.J., Torija, M.J., Mas, A., Mateo, E., 2015. Acetic acid bacteria from biofilm of strawberry vinegar visualized by microscopy and detected by complementing culture-dependent and culture-independent techniques. Food Microbiol. 46, 452
462. Available from: https://doi.org/10.1016/ j.fm.2014.09.006. Valero, E., Berlanga, T.M., Roldan, P.M., Jime´nez, C., Garcı´a, I., Mauricio, J.C., 2005. Free amino acids and volatile compounds in vinegars obtained from different types of substrate. J. Sci. Food Agric. 85 (4), 603
608. Available from: https://doi.org/10.1002/jsfa.2016. Vegas, C., Mateo, E., Gonza´lez, A., Jara, C., Guillamo´n, J.M., Poblet, M., et al., 2010. Population dynamics of acetic acid bacteria during traditional wine vinegar production. Int. J. Food Microbiol. 138 (1
2), 130
136. Available from: https://doi.org/10.1016/j.ijfoodmicro.2010.01.006.

300

Valorization of Fruit Processing By-products

Vegas, C., Gonza´lez, A., Mateo, E., Mas, A., Poblet, M., Torija, M.J., 2013. Evaluation of representativity of the acetic acid bacteria species identified by culture-dependent method during a traditional wine vinegar production. Food Res. Int. 51 (1), 404
411. Available from: https://doi.org/ 10.1016/j.foodres.2012.12.055.

Further reading Matsushita, K., Toyama, H., Tonouchi, N., Okamoto-Kainuma, A. (Eds.), 2016. Acetic Acid Bacteria: Ecology and Physiology. Springer, Japan, ISBN: 9784431559313.

Index Note: Page numbers followed by “f” and “t” refer to figures and tables, respectively.

A AAB. See Acetic acid bacteria (AAB) AAD. See Average American diet (AAD) AAE. See Ascorbic acid equivalents (AAE) Abiotic stress, 70 ABTS. See Azino-bis(3-ethylbenzthiazoline-6sulfonic acid) (ABTS) AC. See Activated carbon (AC) Accelerated solvent extraction (ASE), 72, 114 ACE. See Angiotensin-converting enzyme (ACE) Acetic acid, 219 Acetic acid bacteria (AAB), 285 Acetic fermentation, 175 Acetification, 289
291, 290f Acetobacter, 292
293 A. malorum strain, 289
290 A. rancans, 175 Acetogenic bacteria, 155 Acetone, 32, 72
74 Acid deesterification, 31 Acidic fruit, 18 Activated carbon (AC), 245 Adenosine diphosphate (ADP), 80 AE. See Antiradical efficiency (AE) Aerobic microbial deconstruction, 28 Agricultural waste, 169 Agroindustrial wastes, 175 AI. See Atherogenic index (AI) Alcohol insoluble fiber (AIS), 97 Alcoholic fermentation, 175, 288
289, 289f Aldehydes, 138 Alkali deesterification, 31 D-Allose (C6H12O6), 174 α-amylase, 80 α-glucosidase, 80 Aluminum chloride (AlCl3), 244
245 American Heart Association, 71
72 Amino acids, 294 Amylase, 158
159 Anaerobic digestion, 155 Ananas comosus L. (pineapple), 204 bromelain extraction strategies, 209 bromelain purity, 217
218 configurational considerations, 213
216 membrane filtration process for bromelain extraction, 209
212 membrane technology application in bromelain purification, 213

processing parameters considerations, 216
217 protein utilization from pineapple waste, 204
208 valorization of carbohydrates, 218 value-added products from pineapple waste, 219
220 waste generation estimation in food industry, 204t waste utilization, 204, 206t chemical properties of waste, 205t industrial applications of bromelain, 216t investigations on bromelain separation, 214t Angiotensin-converting enzyme (ACE), 55 Anhydrogalacturonic acid units, 29 Animal feeding, passion fruit peel and seed as, 185 Anthocyanins, 1
2, 3f, 17, 102
103, 104t, 291 extraction, 115 fraction, 191 monomers, 291 Antiatherogenic compounds of avocado, 82t effects, 81
83 pulp, 82
83 seed, 83 Anticancer, 78
80, 79t pulp, 79 seed, 79
80 Anticancerogenic effects, 49
50 Antidiabetic effects, 80
81 pulp, 80
81 seed, 81 Antifungal protein, 196
197 Antihypercholesterolemic effect, 82 Antihyperglycemic effect of avocado, 80f Antiinflammatory activities, 1
2 effect, 86
88 pulp, 87 seed, 87
88 Antimicrobial of berry pomace, 106
108 effect, 10
11, 84
86, 84t peel, 86 pulp, 85 seed, 85
86 Antinutritional substances, 173 Antioxidant(s), 254

activities, 1
2, 138, 196 of berry pomace, 106
108 capacity, 291 effect, 74
78, 75t peel, 77
78 pulp, 76
77 seed, 77 extraction, 32
37 Antioxidants, 17, 129, 139
140, 171 Antiradical compounds. See Antioxidant(s) Antiradical efficiency (AE), 112 Apple, 17 apple-containing fruit filter tea production, 27
28, 27f application of apple processing byproducts, 28
37 by-products, 27 fruit juice production, 18
25, 19f centrifugation, thermal processing of juice, clarification, and filtration, 23
24 mash depectinization in, 21
22 milling of apples and primary thermal treatment, 21 pasteurization, filling, and storage, 24
25 pressing of fruit in, 22
23 quality raw material, 18
20 washing and inspection of apple fruits, 20 fruit processing, 18
28 apple fruit juice production, 18
25 apple-containing fruit filter tea production and by-product remaining, 27
28 by-products of apple fruit juice production, 26
27 concentrated fruit juice production, 25 peel, 26
27 pomace, 18, 26, 28, 30, 241 processing byproducts application, 28
37 pectin, 29
32 seed, 27 Aqueous separation methods, 72
73 Aqueous two-phase system (ATPS), 209, 210t Arabinose, 99 Arachidonic acid, 86 Arctic brambles, 96 Aromatic compounds, 227
228 Ascorbic acid, 229 Ascorbic acid equivalents (AAE), 102
103 ASE. See Accelerated solvent extraction (ASE) Aspergillus flavus, 190

301

302

Index

Aspergillus niger, 175 Aspergillus sojae, 28
29 Atherogenic index (AI), 83 Atherosclerosis, 81
82 Atherothrombosis, 81
82 ATPS. See Aqueous two-phase system (ATPS) Autohydrolysis, 138 Average American diet (AAD), 83 Avocado (AV), 67, 68f ecotypes of, 68
70 extraction of phytochemicals, 72
74 health benefits, 74
88 importers, 69f industrial applications, 88 in languages or recognizes by countries, 69t leading AV producing countries, 68f nutritional composition, 70
72 tree, 67 Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 74, 106, 138, 266

B Baked products fruit pomace application in, 6
9 GPA group average plots for muffin descriptors, 7f BCP. See Black currant pomace (BCP) Bead-milling (BM), 109 Bentonite, 24 Benzaldehyde, 56 Benzyl butyl phthalate, 88 Berry, 96 Berry phytochemicals, 117 Berry pomace, 2
3, 96 antioxidant, antimicrobial, and bioactivities, 106
108 composition, 97
108, 98t cell wall polysaccharides, proteins, and minerals, 97
99 phytochemical composition and bioactivities, 102
108 and seed oil, 99
102 extracts, 118
119 processing conventional solid
liquid extraction, 110
112 enzyme-assisted processing, 114
115 extraction of constituents from, 109
116 extraction with pressurized liquids, 114 multistep biorefining processes, 115
116 postpressing preparation for processing, 108
109 supercritical fluid, pressurized liquid, and HPE, 112
114 UAE and MAE, 112 product application, 116
120 of berry pomace extracts, 118
119 of dried berry pomace, 117
118 encapsulation of pomace ingredients, 119
120 Bertuzzi Food Processing, 185 β-carotene, 50 BHT. See Butylated hydroxytoluene (BHT)

Bilberry pomace, 118 Bio-based products, 115 Bioactive compounds, 1
2, 4, 52, 53t, 57t, 145, 176, 230 Bioactive compounds recovery, 148
150 Bioactive peptide, 55 Bioactive polysaccharides, 233
240 Bioadsorbents for wastewater treatment, 96 Biodiesel, 154 Bioeconomy, 282 concept in citrus waste valorization, 161 Bioenergy, 115 Bioethanol, 28
29, 152
153 Biofertilizer, 155
156 Biogas, 155 Biogenic amines, 294 Biohydrogen, 154
155 Biomass-derived fuels, 146 Biomethane production, 244 Biorefineries, 115, 156
157, 176 Biosorption, 136
137 Biotic stress, 70 Black currant pomace (BCP), 7
8, 8f, 98
99 Blanching water concentrate (BWC), 58, 59f Blueberry, 3
4 BM. See Bead-milling (BM) Bovine serum albumin (BSA), 213
216 Brazil, 183 Bromelain enzyme, 204
208 extraction strategies, 209 comparison of different purification strategies, 212t industrial applications of, 216t investigations on bromelain separation, 214t membrane filtration process for bromelain extraction, 209
212 technology application in bromelain purification, 213 purification techniques for extraction, 210t Bromelain purity, 217
218 BSA. See Bovine serum albumin (BSA) Butylated hydroxytoluene (BHT), 233 BWC. See Blanching water concentrate (BWC) By-products, 1. See also Value-added products of apple fruit juice production, 26
27 apple peel, 26
27 apple pomace, 26 apple seed and apple by-products, 27 of apple processing, 18 apricot, 56
58 application, 58
61, 60t BWC and DWC, 58 pomace, 56
58 thinned apricots, 58 remaining, 27
28

C C-glucoside flavone, 191 C/N ratio. See Carbon/nitrogen ratio (C/N ratio) CA-WoS. See Clavirate Analytics Web of Science (CA-WoS)

Candy preparation, 160
161 Canned mango production, 169 Carbohydrates, 137, 197 metabolism, 5 Carbon dioxide (CO2), 35, 263 Carbon/nitrogen ratio (C/N ratio), 244 Carboxylic groups, 29 Cardiovascular disease (CVD), 70
71 Carotenes, 50 Carotenoids, 49
51, 51f, 106, 227
229 Castanea crenata, 128 Castanea dentata, 128 Castanea mollissima, 128 Castanea sativa (European chestnut), 128 by-products, 128
140 burs, 137
140 flowers, 133
135 leaves, 129
132 shells, 135
137 Catechin, 77, 220 Catechin equivalents (CEs), 97 CBMN assay. See Cytokinesis-block micronucleus assay (CBMN assay) Cell wall polysaccharides, 97
99 Cellulases, 74, 158 enzyme, 21 Cellulose, 218 Cellulose nanocrystals (CNCs), 174 Centrifugation, 23
24 Ceramic membranes, 216 Cerastes cerastes, 174 CEs. See Catechin equivalents (CEs) CHAPS. See 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS) Chelating agents, 218
219 Chemical degradation, 3
4 Chemoprevention, 78 Cherry pomace, 98
99 Chestnut, 128 C. sativa by-products, 128
140 future perspectives, 140 Chokeberry pomace, 10, 98
99 3-[(3-Cholamidopropyl)dimethylammonio]-1propanesulfonate (CHAPS), 52
55 Chromatography, 209, 210t assays, 266
268 Chutney, 169 Cider, 18 Circular economy, 128, 161 Citrus aurantiifolia, 149f Citrus aurantium (bitter oranges), 145 Citrus deliciosa (citrus hybrid mandarin
pomelo), 145 Citrus fruits, 145 bioeconomy concept in citrus waste valorization, 161, 161f future scope, 162 valorization of citrus waste, 148
157 value-added products, 157
161 waste generation and management, 146
148, 147f characteristics of dried and wet citrus fruit waste, 148t

Index

world production, export, and import of citrus varieties, 146f Citrus grandis (pomelo), 145 Citrus jambhiri (rough lemon), 145 Citrus juice production, 4 Citrus karna (Karna Nimbu/KhattaNimbu), 145 Citrus limetta (limon), 145, 149f Citrus limettioides (sweet lime), 145 Citrus limonia (Rangpur), 145, 153f Citrus maxima, 149f Citrus medica, 149f Citrus reticulata (mandarins), 145 Citrus sinensis (sweet oranges), 145, 153f Clarification of juices, 23
24 Clavirate Analytics Web of Science (CAWoS), 96 CNCs. See Cellulose nanocrystals (CNCs) Cold pressing, 99, 151, 193
194 Cold-pressed oil, 195 Colloid carbohydrate derivatives, 29 Colon adenocarcinoma cells, 79 Commercial feed enzymes, 241 Concentrated fruit juice production, 25 Convective drying process, 88 Conventional acid extraction technique, 187
188 Conventional extraction methodologies, 138 of pomegranate waste, 255
258, 256t Conventional optimization techniques, 264 Conventional solid
liquid extraction, 109
112 Conventional solvent extraction, 194 Cooked fruit by-products, 8 Cosmetic industries, 116 COX-2. See Cyclooxygenase (COX-2) Cranberry polyphenolics, 103
105 Cross-linked gluten matrix, 9 Crude waste mixture (CWM), 216 Cupric ion reducing antioxidant capacity (CUPRAC), 74 CVD. See Cardiovascular disease (CVD) CWM. See Crude waste mixture (CWM) Cyanidin 3-glucoside, 187 Cyannidin-3-glucoside (CyGEs), 102
103 Cyanogenic glycosides, 43
44 Cyclohexane, 240 Cyclooxygenase (COX-2), 86 CyGEs. See Cyannidin-3-glucoside (CyGEs) Cytokines, 136 Cytokinesis-block micronucleus assay (CBMN assay), 130
131

D Dearomatization, 25 Debittering water concentrate (DWC), 58, 59f Degenerative diseases, 171 Degree of polymerization (DP), 105, 220, 254 Dehydrated mango, 169 Dehydration, 172
173 Deoxyribonucleic acid (DNA), 129 Depectinization, 21 Depolymerization of lignocellulose, 240 DF. See Dietary fiber (DF) Dietary fiber (DF), 1
2, 4, 189
190, 228
229 composition, 3

DF-rich raw materials, 9 powder, 2
3 production, 159
160 role in human nutrition, 4
5 Dietary phytochemicals, 229 Dihydrochalcones, 17 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 56, 74, 231 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 106, 129, 263, 266 Disposal, 28
29 Distillation process, 151 Dithiothreitol (DTT), 52
55 DM. See Dry matter (DM) DNA. See Deoxyribonucleic acid (DNA) Dodecanoic acid, 88 Downstream processing protocols, 245
247 DP. See Degree of polymerization (DP) Dried berry pomace, 117
118 Dry matter (DM), 97 Dry weight (DW), 96 Drying technique, 160
161 DTT. See Dithiothreitol (DTT) DW. See Dry weight (DW) DWC. See Debittering water concentrate (DWC)

E EA. See Ellagic acid (EA) EAE. See Enzyme-assisted extraction (EAE) Echis colora, 174 Edulilic acid, 191 Electron paramagnetic resonance techniques, 131 Electron transfer mechanism (ET mechanism), 265
266 Ellagic acid (EA), 255 Ellagitannins, 131, 253, 271
272 Encapsulation of pomace ingredients, 119
120 Endocarp, 170, 172 Endogenous enzymes, 4 Energy recovery, 152
157 biodiesel, 154 bioethanol, 152
153 biofertilizer, 155
156 biogas, 155 biohydrogen, 154
155 biorefinery, 156
157 Enriched pure´e (ESP), 293 Enzymatic extraction, 31, 189 Enzyme-assisted extraction (EAE), 109, 264 Enzyme-assisted processing, 114
115 Enzymes, 2, 129, 157
159 amylase, 158
159 cellulases, 158 lipases, 159 pectinases, 157
158 Epicatechin, 77 Episkin test, 139
140 EPP. See Extracted phenolic powder (EPP) ESM. See Thai mango seed extract (ESM) ESP. See Enriched pure´e (ESP) Essential amino acids, 173

303

Essential fatty acids, 49 Essential nutrients, 281 Essential oil apricot, 55
56, 56t recovery, 151
152 expression or cold-pressing, 151 instantaneous controlled pressure drop technique, 152 microwave extraction, 152 steam stripping and distillation, 151 subcritical water extraction, 152 supercritical fluid extraction, 151
152 Esterification, 29
31 ET mechanism. See Electron transfer mechanism (ET mechanism) Ethanol, 189 Ethanolic extraction, 245 EUROSTAT, 184 Expression technique, 151 Extracted phenolic powder (EPP), 119
120 Extraction of apple by-products, 32
37, 33t of constituents from, 109
116 extraction/fractionation methods, 109
110 methods, 88, 103
105, 196 chromatographic assays, 266
268 efficiency assessment, 265
268 spectrophotometry assays, 265
266 of phytochemicals, 72
74, 73f with pressurized liquids and at high pressure, 114 process optimization, 264
265 technique, 187
188, 247
248 ´ leos Naturais, 191 Extrair O Extruded products, 8
9 Extrusion process, 28
29

F FAO. See Food and Agriculture Organization of United Nations (FAO) FAOSTAT database, 184 Fatty acids, 4, 49, 135, 173 Fermentation processes, 175 Fermented products, strawberries to biotransformation of SP into wine and vinegar, 288
296 process development and quality control, 287
288 Ferric reducing antioxidant power (FRAP), 58, 74, 106, 138, 264, 266 Ferrous sulfate equivalent (FSE), 138 Ferulic acid, 220 FFAs. See Free fatty acids (FFAs) Fiber, 5 consumption, 4 fiber-enriched cereals foods, 6 Filipendula ulmaria, 133 Filling, 24
25 Filtration, 23
24 Flavan-3-ols/procyanidins, 17 Flavonoids, 1
2, 148
149, 227
228, 242, 253 Flavonols, 17 aglycones, 119

304

Index

“Florentine flask”, 151 Flour of mango, 171 Flour-based bakery products, 117
118 Folin
Ciocalteu assays, 265 Food loss, 168 processing by-products, 247
248 waste, 168 generation, 145 Food and Agriculture Organization of United Nations (FAO), 67, 128, 184 FPW. See Fruit processing waste (FPW) Fractionation, 268
270 of lipid, 194 method, 103
105 FRAP. See Ferric reducing antioxidant power (FRAP) Fratelli Indelicato company, 185 Free ellagic acid, 118 Free fatty acids (FFAs), 154 Free radicals, 74 Freeze-drying, 2
3 freeze-dried apple pomace, 35
36 Fresh apple slices, 18 Fresh weight (FW), 102
103 Fructooligosaccharides, 240 Fructose, 134
135 Fruit processing waste (FPW), 176 Fruit(s), 96 bioremediation, 176 by-product processing influence of processing on pomace composition, 3
4 pomace processing conditions, 2
3 juices production, 18 pomace application in baked products, 6
9 pressing in apple fruit juice production, 22
23 processing by-products as food ingredients application of fruit pomace in baked products, 6
9 meat products, 10
11 pasta, 9
10 processing of fruit by-products, 2
4 technofunctional and physical properties of processed fruit pomace, 4
6 FSE. See Ferrous sulfate equivalent (FSE) Functional foods, 96 Functional groups, 244
245 3-Furanmethanol (C5H6O2), 174 Fusarium moniliforme, 175 FW. See Fresh weight (FW)

G GA. See Gluconic acid (GA); Gum Arabic (GA) GAE. See Gallic acid equivalent (GAE) Galactooligosaccharides, 240 Galacturonic acid, 23, 99 Gallagic acid, 253 Gallic acid equivalent (GAE), 27
28, 191 Gallotannins, 131 Gazllic acid, 102
103

Gelatine, 23
24 Gelatinized starch, 9
10 Geotrichum klebahnii, 189 Gluconeogenesis, 81 Gluconic acid (GA), 285
286, 291
295, 292f, 294f Gluconobacter, 292
293 Glucose, 99, 134
135, 292, 295f Glucosidase, 4 Glucoside hydrolases, 158 Glutathione, 72 Glycemic index, 286 Glycosylated quercetin, 78 Gram-negative bacteria, 139 Gram-positive bacteria, 139 Grape marc, 116 Grape pomace, 3
4, 96
97 Green economy, 282 Gum Arabic (GA), 119
120 Gums, 218
219

H HACD. See Hot-air convective (HACD) Hass ecotype, 88 HAT. See Hydrogen atom transfer (HAT) Hazardous organic solvents, 109
110 HDL. See High-density lipoprotein (HDL) Health benefits, 74
88 antiatherogenic, 81
83 anticancer, 78
80 antidiabetic, 80
81 antiinflammatory effect, 86
88 antimicrobial effect, 84
86 antioxidant effect, 74
78 of pomegranate fruit extract, 271, 272t Heavy metals, 136
137 Hemicellulose, 218 depolymerization, 240 enzyme, 21 Herbaceous horticultural species, 281 Hexahydroxydiphenoyl-linked glucose, 253 Hexane, 44
49, 73
74 HF PS membrane, 269 HFD. See High-fat diet (HFD) HG. See Homogalacturonan (HG) High hydrostatic pressure, 114 High pressure (HP), 109 High-density lipoprotein (HDL), 71
72 High-esterified pectins (HM pectins), 30 High-fat diet (HFD), 82
83 High-performance liquid chromatography (HPLC), 26
27, 130, 233, 255, 266
267 High-performance tangential flow filtration (HPTFF), 213
216 High-pressure extraction (HPE), 112
114 High-pressure-assisted extraction process, 150 High-voltage electrical discharge, 263 Higuchi model, 131 HM pectins. See High-esterified pectins (HM pectins) HMF. See 5-Hydroxymethylfurfural (HMF) Homogalacturonan (HG), 190 Hot-air convective (HACD), 109

Hot-water separation method, 73 HP. See High pressure (HP) HPE. See High-pressure extraction (HPE) HPLC. See High-performance liquid chromatography (HPLC) HPTFF. See High-performance tangential flow filtration (HPTFF) HT. See Hydrolyzable tannins (HT) Human cancer cell lines, 230
231 Human nutrition, dietary fiber role in, 4
5 Hydroethanolic raspberry pomace, 118 Hydrogen atom transfer (HAT), 266 Hydrolysis/saccharification, 153 Hydrolytic bacteria, 155 Hydrolytic enzymes, 3 Hydrolyzable tannins (HT), 131, 133, 253 Hydrolyzing enzymes, 80 Hydroxycinnamic acids, 17, 96 5-Hydroxymethylfurfural (HMF), 32 Hypercholesterolemia, 81
82 Hyperhomocysteinemia, 72

I ICPD process. See Instant controlled pressure drop process (ICPD process) IKappa-B-alpha (Ikb-α), 87 IL-6. See Interleukin-6 (IL-6) Immature fruit extracts, 172 Incorporating dietary fiber, 8 Inducible nitric oxide synthase (iNOS), 86 Industrial applications, 88 Industrially scalable integrated extraction
adsorption method, 112 Infrared impingement (IRI), 109 Innovative drying approach, 231 iNOS. See Inducible nitric oxide synthase (iNOS) Insoluble fibers, 218 Instant controlled pressure drop process (ICPD process), 263 Instantaneous controlled pressure drop technique, 152 Integrated biorefinery approach, 157f Integrated techniques, 209, 210t Interleukin-6 (IL-6), 87 International Trade Centre (ITC), 253 Inulin, 240 IRI. See Infrared impingement (IRI) Isoorientin, 191 ITC. See International Trade Centre (ITC)

J Jams, 18, 96 “Judia” cultivar, 134 Juices, 18, 96 Juicy fruit, 18

K Kaempferol, 220 Kernel oil, 44
52, 45t carotenoids, 50
51

Index

fatty acids, 49 polyphenols, 51
52 triterpenoids, 50 vitamin E active compounds, 49
50

L Lactase, 61 Lactic acid, 219 Lactic fermentation, 175 Laurus persea.. See Persea americana LDL. See Low-density lipoprotein (LDL) Levoglucosan (C6H10O5), 174 LF. See Lower fat (LF) Lignin, 97 Lignocellulosic wastes, 28
29 Linoleic acid, 49, 99
102 Lipases, 159 Lipids, 70
71, 99, 100t fractionation, 194 lipid-soluble microconstituents, 106 Lipophilic constituents, 106 phytochemicals, 233 Lithium sulfate (Li2SO4), 265 LM pectins. See Low-esterified pectins (LM pectins) “Longal” cultivar, 134 Low-density lipoprotein (LDL), 71
72, 106, 253
254 Low-esterified pectins (LM pectins), 30 Lower fat (LF), 83 Lutein, 50 Luteolin glucoside, 191 Lycopene, 227
228

M Maceration extraction method, 255 MAE. See Microwave-assisted extraction (MAE) Malondialdehyde (MDA), 80 Maltodextrin (MD), 119
120 Mangifera genus, 167 Mangifera indica L. (mango), 167 mango kernel, 170 mango peel powder, 9
10 mango puree, 169 peel, 170
172, 170f seed, 172
174, 172f waste, 169
170 as substrate, 174
177 world production of mango, 167f Mangiferine, 171 Maracuja oil. See Passion fruit—seed oil Mash depectinization in apple fruit juice production, 21
22 Mature fruit extracts, 172 MD. See Maltodextrin (MD) MDA. See Malondialdehyde (MDA) Meat products, 10
11 Mediterranean diet, 71
72 Membrane filtration (MF), 269
270 for bromelain extraction, 209
212

technology, 209, 210t Membrane methods, 24 technology application in bromelain purification, 213 Mesocarp. See Pulp Metabolic syndrome (MetS), 74, 75f Methanogens, 155 Methanol, 32, 72 Methicillin-resistant S. aureus (MRSA), 86 Methoxyl group, 186 Methoxylated flavonoids, 229 Methyl ester of mango seed oil, 173 MetS. See Metabolic syndrome (MetS) MF. See Membrane filtration (MF); Microfiltration (MF); Moderate fat (MF) MHDG. See Microwave hydrodiffusion and gravity (MHDG) Microbial enzymes, 241 Microbial spoilage, 2 Microemulsion system, 176 Microfiltration (MF), 24, 270 Micronutrients, 229 Microwave hydrodiffusion and gravity (MHDG), 109 Microwave vacuum drying (MWVD), 109 Microwave-assisted extraction (MAE), 31
32, 109, 112, 150, 188
189, 240 hexane extraction, 74 Microwave-assisted hot-air (MWHA), 109 Microwave-assisted squeezing extraction, 74 Microwave(s), 263
264 extraction technique, 152 radiation, 2
3 steam diffusion, 152 MICs. See Minimum inhibition concentrations (MICs) Milling of apples and primary thermal treatment, 21 Minerals, 97
99 Minimum inhibition concentrations (MICs), 85, 132 Minitab software, 264 Moderate fat (MF), 83 Molecular weight (MW), 209 Molecular weight cutoff (MWCO), 209 Monocarboxylic organic acids, 49 Monounsaturated fatty acids, 88 MRSA. See Methicillin-resistant S. aureus (MRSA) MSCE. See Multistage countercurrent extraction (MSCE) Multiple regression coefficients, 264 Multistage countercurrent extraction (MSCE), 255
258 Multistage membrane systems, 213
216 Multistep biorefining processes, 115
116 MW. See Molecular weight (MW) MWCO. See Molecular weight cutoff (MWCO) MWHA. See Microwave-assisted hot-air (MWHA) MWVD. See Microwave vacuum drying (MWVD)

305

N Nanofibers, 218 Nanofiltration (NF), 209 Nanoparticles (NPs), 271
272 National Cancer Institute (NCI), 80 Natural antioxidants, 171 Natural high molecular weight compounds, 30 Natural polyphenols, 271 Natural product drug discovery, 230
231 Natural resources, 128 Natural sources, pectin production from, 30
32 NCI. See National Cancer Institute (NCI) NF. See Nanofiltration (NF) NIDDM. See Noninsulin-dependent diabetes mellitus (NIDDM) Nitrogen (N), 156 No-observed-adverse-effect level (NOAEL), 271 Nonalcoholic beverage, 286 Nonanthocyanins, 296 phenolics, 267 Nonconventional extraction methods, 258
264, 259t Nondigestible oligosaccharides, 240 Nondigestible polysaccharides, 97 Nonenzymatic antioxidants, 129 Nonenzyme-assisted centrifugation, 72
73 Noninsulin-dependent diabetes mellitus (NIDDM), 80
81 Nonstarch polysaccharides, 241
242 Nonthermal technology, 231 Nonwater-soluble plant residues, 23 NPs. See Nanoparticles (NPs) Nutraceuticals, 96 Nutrient-enriching microorganisms, 156 Nutritional composition, 70
72 of AV fruit, 71t

O OFAT procedure. See One-factor-at-a-time procedure (OFAT procedure) Oil droplets, 73 oil-squeezing effect, 73 oil
water emulsion, 72
73 oxidation, 271 Oligosaccharides, 240 One-factor-at-a-time procedure (OFAT procedure), 264 ORAC. See Oxygen radical absorbance capacity (ORAC) Orange by-product fiber, 9
10 Organic acids, 135, 159, 219 Organic fertilizers, 155
156 Organic solvents, 32, 171, 254 extraction, 73
74 Osmotic dehydration, 169 Ovalbumin (OVA), 213
216 Oven-drying method, 73 Oxidation reactions, 10 Oxidative stress-related diseases, 137 Oxipres methods, 119 Oxygen radical absorbance capacity (ORAC), 74, 106

306

Index

P P/S. See Polyunsaturated fatty acids to saturated fatty acids ratio (P/S) Pancreatic β-cells, 132 Partial thromboplastin time (pTT), 82 Particle size, 255 Passiflin, 197 Passiflora alata (Sweet passion fruit), 194 Passiflora edulis (purple passion fruit), 183, 184f Passiflora edulis f. flavicarpa (yellow passion fruit), 183, 184f, 194 Passion fruit, 183 animal feeding, 185 components from seed antifungal protein, 196
197 drying of seed, 191 phenolic compounds and antioxidant activities, 196 piceatannol and scirpusin B, 195
196 seed fiber, 197 seed protein, 196 peel extraction, 190
191 peel flour, 190 production, 184, 185t pulp and juice processing, 185 seed oil, 191
195 conventional solvent extraction, 194 extraction, 193
194 fatty acid compositions, 193 fractionation of lipid, 194 miscellaneous applications, 195 physical and chemical characteristics, 192 super-and subcritical fluid extraction, 194 unsaponifiable components, 193 valuable components from peel dietary fiber, 189
190 drying of peel, 185
186 pectin and pectic oligosaccharides, 186
189 Pasta, 9
10, 9f Pasteurization, 24
25 Pectic acids, 29
30 Pectin, 26, 171, 189
190, 218
219 extraction of apple by-products, 32
37 hydrolysate, 30
31 importance, 29
30 and pectic oligosaccharides, 186
189 enzymatic extraction, 189 extraction, 187
188 microwave-and ultrasound-assisted extractions, 188
189 physical and chemical characteristics, 187 subcritical water extraction, 189 production of pectin from natural sources, 30
32 Pectinases, 157
158 Pectinex, 97 Pectinic acid, 29
30 Pectolytic enzymes, 23 Peel antimicrobial effect, 86

antioxidant effect, 77
78 Penicillium purpurogenum GE1, 241 Penicillium verruculosum, 190 Pentose phosphate pathway, 292 PEPP. See Purified extracted phenolic powder (PEPP) Peptides, 52, 55 Peroxide values (PVs), 102 Persea americana, 67 Persea americana var. americana (West Indian ecotype), 68
70 Persea americana var. drymifolia (Mexican ecotype), 68
70 Persea americana var. guatemalensis (Guatemalan ecotype), 68
70 PFAs. See Polyhydroxylated fatty alcohols (PFAs) PGE2. See Prostaglandin E2 (PGE2) Phenolic acids, 1
2, 51 antioxidants, 220 compounds, 3
4, 49, 52f, 102
105, 135
136, 191, 196, 227
228, 242 Phenolics, 253 Phenols, 29 Phloretin 2ʹ-xyloglucoside, 17 Phloridzin, 17 Phosphinothricin, 70 Phosphoenolpyruvate carboxykinase, 119 Phospholipase A (PLA2), 86 Phosphorous (P), 156 Phytochemicals, 1, 17, 229 extraction, 72
74 on pink guava fruits, 233
240 recovery, 148
150 high-pressure-assisted extraction, 150 ultrasound treatment, 150 Phytostanols, 50 Phytosterols, 49
50 Piceatannol, 195
196, 195f Pigments, 171 Pink guava, 227
228 by-products, 228
229, 243t constraints and challenges in reutilizing pink guava by-products, 245
247 functional properties and health-promoting effects of phytochemical constituents, 229
231 further research to filling knowledge gap, 247
248 phytochemical extraction, 233
240 prebiotics ingredients, 240 processing method to minimizing waste after extraction, 242
245 routes to upgrading pink guava by-products commercialization values, 231
242 solvent extraction method, nonvolatile bioactive compounds from, 234t substrate for fermentation, 241
242 microbial enzymes, 241 SCP, 241
242

Pink-flesh guava, 227 Pit. See Endocarp PLA2. See Phospholipase A (PLA2) Plackett
Burman design, 159 Plant biomass, 240 Plate heat exchanger, 23 PLE. See Pressurized liquid extraction (PLE) PLGA-PEG. See Poly(D,L-lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) Polar anthocyanin structure pigments, 106 Polar phytochemicals, 233 Poly-DL-lactide-co-glycolide (PLGA), 194 Poly(D,L-lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG), 271
272 Polygalacturonases, 74 Polygalacturonic acids, 29 Polyhydroxylated fatty alcohols (PFAs), 87 Polyphenol(s), 3
4, 51
52, 102
103, 134, 242, 281 compounds, 265
266 content, 138 extraction, 56 extraction of pomegranate waste, 254
265 conventional extraction methods, 255
258, 256t extraction process optimization, 264
265 nonconventional extraction methods, 258
264, 259t process conditions in solid
liquid extraction, 254
255 Polyphenolic groups, 17 Polyphenoloxidase, 4 Polysaccharides, 139
140, 171, 190 Polysulfone (PS), 269 Polyunsaturated fatty acids (PUFAs), 96, 133
134 PUFA-rich berry seed oils, 108
109 Polyunsaturated fatty acids to saturated fatty acids ratio (P/S), 71
72 Pomace, 1, 56
58. See also Apple—pomace; Berry pomace apricot, 56
58 BCP, 7
8, 8f, 98
99 bilberry, 118 bioactivities of, 102
108 cherry, 98
99 composition, 3
4 dried berry, 117
118 grape, 3
4, 96
97 hydroethanolic raspberry, 118 ingredients, 119
120 mango, 171 phytochemical composition and bioactivities lipophilic constituents, 106 phenolic compounds, 102
105 processing conditions, 2
3 raspberry, 108, 111f, 119f as source of dietary fiber and bioactive compounds, 4 Postpressing preparation of berry pomace for processing, 108
109

Index

Potassium (K), 156 Prebiotics ingredients, 240 Precipitation method, 209, 210t Preserves, 96 Press residue, 97 Pressed grapeseed oil, 99 Pressurized liquid, 112
114 extraction with pressurized liquids, 114 Pressurized liquid extraction (PLE), 109, 196 Pressurized solvent extraction methods, 263 Primarily food waste, 145 Primary thermal treatment for apple fruit juice production, 21 Primary-generated apple pomace waste, 37 Proanthocyanidins, 253 Probiotic bacteria, 219 Process condition optimization, 255 in solid
liquid extraction, 254
255 Process development and quality control, 287
288 Process parameter optimization, 255 Processed fruit pomace properties physical properties of processed fruit pomace, 5
6 pomace as source of dietary fiber and bioactive compounds, 4 role of dietary fiber in human nutrition, 4
5 Prostaglandin E2 (PGE2), 87 Protective colloids, 23 Proteins, 52
55, 97
99, 196 enrichment, 241
242 extraction from vegetable sources, 52
55 utilization from pineapple waste, 204
208 Prothrombin time (PT), 82 Protopectin, 29
30 hydrolysis, 30
31 Protopectinase, 189 Protopectins, 21 Prunus armeniaca L. (apricot), 43, 44f apricot by-products, 56
58 essential oil, 55
56 kernel, 44
56 oil, 44
52 skin and press cake, 52
55 PS. See Polysulfone (PS) Psidium guajava L. (Guava), 227 guava pomace, 230 PT. See Prothrombin time (PT) pTT. See Partial thromboplastin time (pTT) PUFAs. See Polyunsaturated fatty acids (PUFAs) Pulp, 170 antiatherogenic, 82
83 anticancer, 79 antidiabetic, 80
81 antiinflammatory effect, 87 antimicrobial effect, 85 antioxidant effect, 76
77 Punica granatum L. (pomegranate), 253

extraction method efficiency assessment, 265
268 health benefits, safety assessment, and stability of extract, 270
272 industrial wastes, 268 polyphenol extraction of pomegranate waste, 254
265 purification and fractionation, 268
270 seed powder, 9
10 Purees, 96 Purification, 268
270 membrane filtration process, 269
270 method, 103
105 preparative chromatography for isolation/ purification process, 269 process through selective adsorption, 269 Purified extracted phenolic powder (PEPP), 119
120 PVs. See Peroxide values (PVs)

Q Quality raw material, 18
20 Quercetin (QEs), 102
103, 220

R Radical scavengers. See Antioxidant(s) Radical scavenging activity, 266 Radical-scavenging activity (RSA), 52 Raphanus sativus, 132 Raspberry pomace, 108, 111f, 119f Reactive nitrogen species (RNS), 129 Reactive oxygen species (ROS), 51, 129, 136 Recycling methods, 1 Regression analysis, 264 Relative humidity (RH), 131 Renewable natural resources, 282 Residual biomass, 146 Response surface methodology (RSM), 110, 264 Reverse micelle system (RMS), 209, 210t Reverse osmosis (RO), 209 Reverse osmosis concentration, 25 Reverse phase HPLC-ESI-TOF mass spectrometry, 138
139 RG-1. See Rhamnogalactorunan-1 (RG-1) RGII. See Rhamnogalacturonan II (RGII) RH. See Relative humidity (RH) Rhamnogalactorunan-1 (RG-1), 190 Rhamnogalacturonan II (RGII), 98
99, 186 RhE-models, 139
140 Ripe fruits, 170 Ripening stages (RSs), 76
77 RMS. See Reverse micelle system (RMS) RNS. See Reactive nitrogen species (RNS) RO. See Reverse osmosis (RO) Rohapect, 97 ROS. See Reactive oxygen species (ROS) Rosa micrantha, 133 RSA. See Radical-scavenging activity (RSA)

307

RSM. See Response surface methodology (RSM) RSs. See Ripening stages (RSs) Rutin, 130

S S/A ratio. See Sugar/acid ratio (S/A ratio) Saccharification, 244 Saccharomyces bayanus, 288 Saccharomyces cerevisiae, 28, 153, 244, 288 Safety assessment of pomegranate fruit extract, 270
272 Saturated fatty acids (SFAs), 49, 133
134 Sauce, apple, 18 Scientific Committee on Consumer Safety (SCCS), 140 Scirpusin B, 195
196, 195f Scopus database, 183 SCP. See Single-cell protein (SCP) SE. See Soxhlet extraction (SE) Seed, 77 antiatherogenic, 83 anticancer, 79
80 antidiabetic, 81 antiinflammatory effect, 87
88 antimicrobial effect, 85
86 antioxidant effect, 77 fiber of passion fruit, 197 oil, 99
102 protein, 196 Semicontinuous fed-batch mode, 290
291 Separate hydrolysis and fermentation (SHF), 153 Separation enzymes, 21 SFAs. See Saturated fatty acids (SFAs) SFE-CO2. See Supercritical fluid extraction with carbon dioxide (SFE-CO2) SFEs. See Supercritical fluid extractions (SFEs) SHF. See Separate hydrolysis and fermentation (SHF) Silicon carbide (SiC), 216 Simple sugars, 219 Simultaneous saccharification and fermentation (SSF), 153 Single-cell protein (SCP), 160, 241
242 Skin and press cake, 52
55 extraction method, composition, and activity of bioactive compounds, 53t peptides, 55 polyphenols, 52 proteins, 52
55 SmF. See Submerged/liquid (SmF) SNP. See Sodium nitroprusside (SNP) Sodium hexamethaphosphate, 31 Sodium molybdate (Na2MoO4), 265 Sodium nitroprusside (SNP), 81 Sodium tungstate (Na2WO4), 265 Soil to soil technology, 156 Solid waste, 145
146 Solid-phase extraction protocols (SPE protocols), 267
268, 267f

308

Index

Solid-phase microextraction liquid chromatography and mass spectrometry (SPE/HPLC-DAD-ESI-MS), 266
267 Solid-state fermentation (SSF), 96, 158, 174 Solid
liquid extraction of polyphenols, 254
255 Soluble dietary fiber, 1
2, 4 Soluble fibers, 218
219 Solute rejection, 270 Solvent extraction, 44
49 solvent-free microwave-based technology, 152 systems, 233 Somatic embryogenesis, 70 Soxhlet apparatus, 138 extractor, 44
49 method, 255 Soxhlet extraction (SE), 109, 194 SP. See Strawberry pure´e (SP) SPE protocols. See Solid-phase extraction protocols (SPE protocols) Spectrophotometry assays, 265
266 methods, 233 Spray-dried polyphenol
protein particles, 119 Spray-drying, 2
3, 271 Squalene, 50 SSF. See Simultaneous saccharification and fermentation (SSF); Solid-state fermentation (SSF) Steam explosion, 155 Steam stripping process, 151 Steviol glycosides, 6
7 Stilbenes, 1
2 Stilbenoids, 195, 195f Strawberry, 281 composition, 284t development of new products, 285
286, 286f European strawberry producers, 283f percentage share of strawberry production, 282f strawberries to fermented products, 287
296 strawberry producers in world, 283f variation of global production of fruits, 282f Strawberry pure´e (SP), 287f, 288 biotransformation into wine and vinegar, 288
296 acetification, 289
291 alcoholic fermentation, 288
289 into fermented product containing gluconic acid, 291
295 strawberry beverage storage, 296 Streptozotocin (STZ), 81, 132 Subcritical extraction, 114 fluid extraction, 194 water extraction, 152, 189, 263 Subcritical WE (SWE), 32 Submerged/liquid (SmF), 174 Succinic acid, 219

Sucrose, 135 Sugar/acid ratio (S/A ratio), 17 Sulfur-containing constituents, 227
228 Sun-drying method, 73 Supercritical carbon dioxide (SC-CO2). See Supercritical fluid extractions (SFEs) Supercritical fluid, 112
114 Supercritical fluid extraction with carbon dioxide (SFE-CO2), 99 Supercritical fluid extractions (SFEs), 32, 35, 74, 194, 233, 263 technique, 150
152 Superheated hexane extraction, 263 Suppress tumor cells growth, 88 Sustainability, 128 Sustainable waste stream management, 1 SWE. See Subcritical WE (SWE)

T TAGs. See Triacylglycerols (TAGs) Tannin, 23
24 “Tannin
gelatine” complex, 23
24 TBARS. See Thiobarbituric acid reactive substances (TBARS) TEAC. See Trolox equivalent antioxidant capacity (TEAC) Terpenoids, 138 TEs. See Trolox equivalents (TEs) TEWL. See Transepidermal water loss (TEWL) TFC. See Total flavonoid content (TFC) TFs. See Total flavonoids (TFs) Thai mango seed extract (ESM), 176 Thailand passion fruit, 183 Thermal processing of juice, 23
24 Thermal technology, 231 Thinned apricots, 58 Thiobarbituric acid reactive substances (TBARS), 10, 11f TMAs. See Total or monomeric anthocyanins (TMAs) TMP. See Transmembrane pressure (TMP) Tocochromanols, 49 Tocols, 193 Tocopherols, 49
50, 106, 107t, 113, 137 Tocotrienols, 49
50, 137 Total flavonoid content (TFC), 74 Total flavonoids (TFs), 264 Total or monomeric anthocyanins (TMAs), 102
103 Total phenolic compounds, 25 Total phenolic content (TPC), 51
52, 74, 96, 255 Total phenols, 291 Total procyanidins (TPCd), 102
103 TPC. See Total phenolic content (TPC) TPCd. See Total procyanidins (TPCd) 3,4,3ʹ,5ʹ-Trans-tetrahydroxystilbene. See Piceatannol Transepidermal water loss (TEWL), 130 Transmembrane pressure (TMP), 216
217, 269

Triacylglycerols (TAGs), 102 Trichoderma harzianum, 28
29 Triterpenoids, 50 Trolox equivalent antioxidant capacity (TEAC), 74, 266 Trolox equivalents (TEs), 102
103, 129
130, 266 Tubular heat exchangers, 21 Twisselmann extractor, 44
49

U Ultrafiltration (UF), 24, 269, 270f Ultrasonic waves, 194 Ultrasonic-assisted extraction, 240 Ultrasound treatment, 150 ultrasound-assisted drying, 185
186 Ultrasound-assisted extraction (UAE), 31
32, 109, 112, 150, 188
189, 263 Ultraviolet B (UVB), 87 Ultraviolet radiation (UV radiation), 129 Unsaturated fatty acids (UFAs), 49 US Food and Drug Administration (USFDA), 285
286

V Vacuum impregnation, 231 Vacuum microwave hydrodistillation technique, 152 Valorization of apple by-products through antioxidants extraction, 32
37 of berries application of berry pomace products, 116
120 composition of berry pomace, 97
108 processing of berry pomace, 108
116 of citrus waste, 148
157 energy recovery, 152
157 essential oil recovery, 151
152 phytochemicals/bioactive compounds recovery, 148
150 of pineapple carbohydrates insoluble fibers, 218 simple sugars, 219 soluble fibers, 218
219 Value-added products. See also By-products of citrus fruits candy preparation, 160
161 enzymes production, 157
159 organic acid production, 159 SCP production, 160 single cell protein production, 160 from pineapple waste, 219
220 Vanillic acid, 220 Vegetables, 96 protein extraction from vegetable sources, 52
55 Vinegar, 18, 288
296

Index

Vitamin C, 281 Vitamin E, 137 active compounds, 49
50 Volatile compounds, 233, 240 Volatile solid content (VS), 154
155 Volume reduction factor (VRF), 217

Water-binding capacity, 5, 6f Water-holding capacity, 5
6 Water-soluble polysaccharides, 233 White-flesh guava, 227 Wine, 288
296

W

X

Washing and inspection of apple fruits, 20 Water absorption index, 117
118 Water activity (aw), 25

Xanthophylls, 50 Xylitol, 220 Xylooligosaccharides (XOS), 220

Y Yeast thermophilic anaerobic bacterial species, 153

Z Zeaxanthin, 50 Zero-waste concepts, 115 Zinc oxide (ZnO), 140 Zirconium oxide, 216 Zymomonas mobilis, 153

309