Food wastes and by-products : nutraceutical and health potential [First edition] 9781119534129, 1119534127, 9781119534136, 1119534135, 9781119534167, 111953416X, 9781119534105

Table of contents :
Content: Cereal/Grain By-products / Norma Julieta Salazar-López, Maribel Ovando-Martínez, J Abraham Domínguez-Avila --
Enrichment and Utilization of Thin Stillage By-products / Timothy J Tse, Martin J T Reaney --
Pulse By-products / Iván Luzardo-Ocampo, M Liceth Cuellar-Nuñez, B Dave Oomah, Guadalupe Loarca-Piña --
Aquafaba, from Food Waste to a Value-Added Product / Rana Mustafa, Martin J T Reaney --
Brazilian (North and Northeast) Fruit By-Products / Larissa Morais Ribeiro Silva, Paulo Henrique Machado Sousa, Luiz Bruno Sabino, Giovana Matias Prado, Lucicleia Barros Vasconcelos Torres, Geraldo Arraes Maia, Raimundo Wilane Figueiredo, Nágila Maria Pontes Silva Ricardo --
Health Benefits of Mango By-products / Abraham Wall-Medrano, Francisco J Olivas-Aguirre, Jesus F Ayala-Zavala, J Abraham Domínguez-Avila, Gustavo A Gonzalez-Aguilar, Luz A Herrera-Cazares, Marcela Gaytan-Martinez --
Citrus Waste Recovery for Sustainable Nutrition and Health / Adriana Maite Fernández-Fernández, Eduardo Dellacassa, Alejandra Medrano-Fernandez, María Dolores Castillo --
Vegetable By-products / L Gabriela Espinosa-Alonso, Maribel Valdez-Morales, Xochitl Aparicio-Fernandez, Sergio Medina-Godoy, Fidel Guevara-Lara --
Flaxseed By-products / B Dave Oomah --
Seed Hull Utilization / EE Martinez-Soberanes, R Mustafa, Martin JT Reaney, WJ Zhang --
Health Benefits of Spent Coffee Grounds / Norma Julieta Salazar-López, Carlos Vladimir López-Rodríguez, Diego Antonio Hernández-Montoya, Rocio Campos-Vega --
Health Benefits of Silverskin / Amaia Iriondo-DeHond, Teresa Herrera, María Dolores Castillo --
Cocoa By-products / Karen Haydeé Nieto Figueroa, Nancy Viridiana Mendoza García, Rocio Campos Vega --
Emerging and Potential Bio-Applications of Agro-Industrial By-products Through Implementation of Nanobiotechnology / Haydé Azeneth Vergara-Castañeda, Gabriel Luna-Bárcenas, Héctor Pool.

Citation preview

Food Wastes and By-products

Food Wastes and By‐products Nutraceutical and Health Potential Edited by Rocio Campos‐Vega

Programa de Posgrado en Alimentos del Centro de la República (PROPAC) Research and Graduate Studies in Food Science School of Chemistry Universidad Autónoma de Querétaro México

B. Dave Oomah

(Retired) Formerly with Summerland Research and Development Centre Agriculture and Agri‐Food Canada Summerland, BC, Canada

Haydé Azeneth Vergara‐Castañeda Facultad de Medicina Universidad Autónoma de Querétaro Querétaro, México

This edition first published 2020 © 2020 John Wiley & Sons Ltd All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions. The right of Rocio Campos‐Vega, B. Dave Oomah, and Haydé Azeneth Vergara‐Castañeda to be identified as the editors of this work has been asserted in accordance with law. Registered Office(s) John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Editorial Office The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com. Wiley also publishes its books in a variety of electronic formats and by print‐on‐demand. Some content that appears in standard print versions of this book may not be available in other formats. Limit of Liability/Disclaimer of Warranty While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Library of Congress Cataloging-in-Publication Data is available for this title 9781119534105 (hardback) Cover image: © Craevschii Family/Shutterstock Cover design by Wiley Set in 9.5/12.5pt STIXTwoText by SPi Global, Pondicherry, India 10  9  8  7  6  5  4  3  2  1

v

Contents List of Contributors  xv 1

1.1 1.2 1.3 1.3.1 1.3.2 1.3.2.1 1.3.2.2 1.3.2.3 1.3.2.4 1.3.2.5 1.3.2.6 1.3.2.7 1.4 1.5 1.5.1 1.5.1.1 1.5.1.2 1.5.1.3 1.5.1.4 1.5.1.5 1.5.1.6 1.5.1.7 1.6 1.6.1

Cereal/Grain By-products  1 Norma Julieta Salazar-López, Maribel Ovando-Martínez, and J. Abraham Domínguez-Avila ­Introduction  1 ­Global Production of Cereals and Crop Residues  2 ­Cereal Processing and Production of By-products  5 Cereals Morphology and Composition  5 Cereal Grains Processing  6 Milling  6 Dry Milling  6 Wet Milling  6 Pearling  7 Malting  8 Fermentation  8 Others  9 ­Cereal Grains By-products  9 ­Nutraceutical from Cereal/Grain By-products  11 Classification of Nutraceutical Ingredients in Cereal By-products  12 Polyphenols  12 Carotenoids  16 Dietary Fiber  16 Prebiotics  17 Lipids and Fatty Acids  17 Proteins  18 Starch  18 ­Health Potential of Cereal/Grain By-products  18 Non-Communicable Diseases  18

vi

Contents

1.6.1.1 1.6.1.2 1.6.1.3 1.7 1.8

Dyslipidemia and Cardiovascular Effect  18 Diabetes  22 Anticancer Effect  23 ­Current and Future Perspectives  25 ­Concluding Remarks  26 References  26

2

Enrichment and Utilization of Thin Stillage By‑products  35 Timothy J. Tse and Martin J. T. Reaney ­Introduction  35 ­Endemic Bacteria in Wheat‐Based Thin Stillage  37 Protein and Organic Solute Concentration in Thin Stillage  39 ­Bacteriocins  43 ­Separation and Purification of Bacteriocins  46 ­Conclusion  47 References  48

2.1 2.2 2.3 2.4 2.5 2.6 3

3.1 3.2 3.3 3.4 3.5 3.6 3.6.1 3.6.2 3.7 4 4.1 4.2 4.3 4.4 4.5 4.5.1 4.5.2 4.6

Pulse By-products  59 Iván Luzardo-Ocampo, M. Liceth Cuellar-Nuñez, B. Dave Oomah, and Guadalupe Loarca-Piña ­Introduction  59 ­Beans By-products  62 ­Pea (Pisum sativum) By-products  68 ­Chickpea (Cicer arietinum) and Lentil (Lens culinaris) By-products  71 ­Lupin (Lupinus) By-products  72 ­Other Pulse By-products  74 Pigeon Pea (Cajanus cajan L.)  74 Broad Beans (Vicia faba)  75 ­Concluding Remarks  78 References  86 Aquafaba, from Food Waste to a Value-Added Product  93 Rana Mustafa and Martin J. T. Reaney ­Introduction  93 ­Plant-based Dairy and Eggs Replacement  94 ­History of Use and Etymology  95 ­Composition of Chickpea and Aquafaba  96 ­Anti-nutritional Compounds  98 Protein Anti-nutritional Compounds  100 Nonprotein Anti-nutritional Compounds  100 ­Functional Properties  101

Contents

4.6.1 4.6.2 4.6.3 4.6.4 4.7 4.7.1 4.7.2 4.8 4.9 4.10 4.11

Water Holding Capacity and Oil Holding Capacity  102 Emulsion Stabilizer  103 Foaming Properties  104 Gelling and Thickening Properties  107 ­Factors Affecting Functional Properties  108 Effect of Cultivars and Genotypes  108 Effect of Processing Methods  110 ­Environmental Impact  112 ­Value-added Products for the Food and Pharmaceutical Industries  113 ­Current and Future Perspectives  115 ­Conclusion  116 References  116

5

Brazilian (North and Northeast) Fruit By-Products  127 Larissa Morais Ribeiro DA Silva, Paulo Henrique Machado de Sousa, Luiz Bruno de Sousa Sabino, Giovana Matias do Prado, Lucicleia Barros Vasconcelos Torres, Geraldo Arraes Maia, Raimundo Wilane de Figueiredo, and Nágila Maria Pontes Silva Ricardo ­Introduction  127 ­Coproducts’ Origin  131 ­Types of Waste Processing  131 ­Bioactive Compounds  132 Vitamin C  133 Phenolic Compounds  134 Antioxidant Activity in Fruit Coproducts  136 Phytosterols in Fruit Coproducts  141 ­Brazilian Fruit By-products from the North and Northeast as a Source of Colorants  141 ­Brazilian North and Northeast Fruit By-products as Source of Polysaccharides  144 ­Brazilian North and Northeast Fruit By-products as Source of Fibers  145 ­Conclusions  149 References  149

5.1 5.2 5.3 5.4 5.4.1 5.4.2 5.4.3 5.4.4 5.5 5.6 5.7 5.8 6

6.1 6.2

Health Benefits of Mango By-products  159 Abraham Wall-Medrano, Francisco J. Olivas-Aguirre, Jesus F. Ayala-Zavala, J. Abraham Domínguez-Avila, Gustavo A. Gonzalez-Aguilar, Luz A. HerreraCazares, and Marcela Gaytan-Martinez ­Introduction  159 ­Mango Agro wastes and Industrial By-products  161

vii

viii

Contents

6.2.1 6.2.1.1 6.2.1.2 6.2.2 6.3 6.3.1 6.3.1.1 6.3.1.2 6.3.1.3 6.3.2 6.4 6.4.1 6.4.1.1 6.4.1.2 6.4.1.3 6.4.2 6.4.2.1 6.4.2.2 6.4.2.3 6.4.2.4 6.4.2.5 6.4.2.6 7

7.1 7.2 7.2.1 7.2.2 7.3 7.4 7.5 7.6

Impacts of Generating Mango Wastes and By-products  162 Economic Impact  163 Environmental Impact  163 Research and Development (R&D)  164 ­Nutritional and Functional Value of Mango Wastes and By-products  165 Nutritional and Functional Value of Mango Wastes and By-products  165 Macro/Micronutrients  165 Dietary Fiber  166 Phenolic Compounds  168 Metabolic Fate of Phytochemicals from Mango By-products  170 ­Potential Health Benefits of Mango Wastes and By-products  171 Infectious Diseases  171 Antibiotic Effect: Planktonic Cells  172 Antibiotic Effect: Biofilms  174 Prebiotic Effects  176 Noncommunicable Chronic Diseases (NCCDs)  176 Obesity  177 Diabetes Mellitus  177 Cardiovascular Diseases (CVDs)  179 Cancer  180 Inflammatory Diseases  181 Neurological Diseases  182 Acknowledgements  182 References  183 Citrus Waste Recovery for Sustainable Nutrition and Health  193 Adriana Maite Fernández-Fernández, Eduardo Dellacassa, Alejandra Medrano-Fernandez, and María Dolores Del Castillo ­Introduction  193 ­Citrus By-products: Natural Sources of Health-Promoting Food Ingredients  194 Polyphenols  196 Antioxidant dietary fiber  198 ­Health-Promoting Effects  200 ­Food Applications  208 ­Safety  210 ­Conclusions  210 Acknowledgments  210 References  211

Contents

8

8.1 8.2 8.2.1 8.2.2 8.2.3 8.2.4 8.2.5 8.3 8.3.1 8.3.2 8.3.3 8.4 8.4.1 8.4.2 8.4.3 8.4.4 8.4.5 8.5 8.5.1 8.5.2 8.5.3 8.5.4 8.5.4.1 8.5.4.2 8.5.4.3 8.5.5 8.5.5.1 8.5.5.2 8.5.5.3 8.5.5.4 8.6 8.7 8.7.1 8.7.2

Vegetable By-products  223 L. Gabriela Espinosa-Alonso, Maribel Valdez-Morales, Xochitl AparicioFernandez, Sergio Medina-Godoy, and Fidel Guevara-Lara ­Introduction  223 ­Global and/or by Region Vegetable Food Production and Postharvest Waste  226 Tomato  227 Chili  229 Broccoli and Cauliflower  229 Zucchini  230 Cucumber  230 ­Global and/or Regional Vegetable Industrialization and By-Product Generation  231 Tomato  231 Chili  232 Broccoli and Cauliflower  235 ­Nutraceutical Composition  236 Tomato  236 Chili  237 Broccoli and Cauliflower  238 Zucchini  239 Cucumber  241 ­Proven Nutraceutical In Vitro and In Vivo Bioactivity  242 Tomato  242 Chili  243 Broccoli and Cauliflower  245 Zucchini  245 Fruit  245 Peel  246 Leaves and Stems  247 Cucumber  247 Fruit  248 Seeds  249 Peel  250 Leaves and Stems  250 ­Methods and Strategies Used by the Food Sector and Other Industries  251 ­Commercialization or Transformation in  Value-Added Products  253 Tomato  253 Seed Chili  254

ix

x

Contents

8.7.3 8.7.4

Broccoli and Cauliflower  255 Zucchini  256 Acknowledgments  256 References  256

9

Flaxseed By-products  267 B. Dave Oomah ­Introduction  267 ­Flaxseed Protein  269 Extraction  269 Composition  272 Amino Acid Profile  273 Product Application  275 ­Advanced Processing  276 ­Mucilage  277 ­Current Trends and Perspectives  278 Acknowledgments  283 References  283

9.1 9.2 9.2.1 9.2.2 9.2.3 9.2.4 9.3 9.4 9.5 10 10.1 10.2 10.3 10.3.1 10.3.2 10.3.3 10.4 10.4.1 10.4.2 10.5 10.5.1 10.5.2 10.5.3 10.5.4 10.5.5 10.5.6 10.6

Seed Hull Utilization  291 E.E. Martinez-Soberanes, R. Mustafa, Martin J.T. Reaney, and W.J. Zhang ­Introduction  291 ­Seed Hull Production  292 ­Seed Hull Composition  294 Dietary Fiber (DF)  295 Phytochemicals  297 Protein and Other Minor Components  303 ­Dehulling Technology  304 Seed Dehulling  304 Dehulling Technology  305 ­Recovery of Compounds from Seed Hull  308 Traditional Solvent Extraction  309 Ultrasonic-Assisted Extraction  310 Microwave-Assisted Extraction  312 Supercritical Fluid Extraction  313 Membrane Separation  314 Seed Hull in Value-Added Food Products  316 ­Prospects and Challenges  316 References  317

Contents

11

11.1 11.2 11.3 11.3.1 11.3.2 11.3.3 11.3.4 11.4 11.5 11.5.1 11.5.2 11.5.3 11.5.4 11.5.5 11.6 11.6.1 11.6.2 11.6.3 11.6.4 11.7 11.7.1 11.7.2 11.7.3 11.7.4 12 12.1 12.2 12.3 12.3.1 12.3.2 12.4 12.5

Health Benefits of Spent Coffee Grounds  327 Norma Julieta Salazar-López, Carlos Vladimir López-Rodríguez, Diego Antonio Hernández-Montoya, and Rocio Campos-Vega ­Introduction  327 ­Coffea Arabica L. Generalities  328 ­Coffee Processing and By-products  329 Coffee Husks  330 Coffee Pulp  330 Coffee Silverskin  331 Spent Coffee Grounds  331 ­Physicochemical Characteristics in SCG  331 ­Nutritional Properties of SCG  333 Carbohydrates  334 Proteins  336 Lipids  336 Minerals  337 Feed Quality  337 ­Nutraceuticals in SCG  338 Dietary Fiber  339 Resistant Starch  339 Antioxidant Compounds  340 Antioxidant Dietary Fiber  341 ­Health Benefits of Spent Coffee Grounds  341 Weight Management and Obesity  342 Cardiovascular Diseases  344 Gastrointestinal Diseases  345 Cancer  346 References  348 Health Benefits of Silverskin  353 Amaia Iriondo-DeHond, Teresa Herrera, and María Dolores Del Castillo ­Introduction  353 ­Improvement of Gastrointestinal Health  358 ­Prevention of Metabolic Disorders  359 Obesity and Dyslipemia  360 Diabetes  362 ­Improvement of Skin Health  363 ­Conclusions  366 Acknowledgements  366 References  367

xi

xii

Contents

Cocoa By‐products  373 Karen Haydeé Nieto Figueroa, Nancy Viridiana Mendoza García, and Rocio Campos-Vega 13.1 ­Introduction  373 13.2 ­Cocoa Bean Shell  376 13.2.1 Chemical Composition  376 13.2.2 Nutraceutical Composition  377 13.2.2.1 Dietary Fiber  377 13.2.2.2 Phenolic Compounds  378 13.2.2.3 Methylxanthines  379 13.2.2.4 Other Compounds  380 13.2.3 Applications  381 13.2.3.1 Feedstuff  381 13.2.3.2 Agriculture  382 13.2.3.3 Biofuels  382 13.2.3.4 Adsorbent  382 13.2.3.5 Dye  383 13.2.3.6 Food Products  383 13.2.3.7 Cocoa Shell Tea  383 13.2.3.8 Cocoa Hulls Polyphenols as a Functional Ingredient for Bakery Applications  383 13.2.3.9 Bio‐Recyclable Paper Packaging  384 13.2.3.10 Cocoa Shell Extracts  384 13.3 ­Cocoa Pod Husk  386 13.3.1 Chemical Composition  387 13.3.2 Drying Methods  387 13.3.3 Nutraceutical Composition  388 13.3.3.1 Dietary Fiber  388 13.3.3.2 Antioxidants  390 13.3.3.3 Theobromine  391 13.3.3.4 Other Compounds  392 13.3.4 Applications  393 13.3.4.1 Animal Feed  393 13.3.4.2 Soap Making  394 13.3.4.3 Activated Carbon  394 13.3.4.4 Fertilizer and Soil Organic Matter  394 13.3.4.5 Paper Making  395 13.3.4.6 Biofuels and Chemical Industry  395 13.3.4.7 Gums  396 13.3.4.8 Source of Enzymes  396 13.4 ­Cocoa Mucilage/Pulp/Sweating  396 13

Contents

13.4.1 13.4.2 13.4.2.1 13.4.2.2 13.4.3 13.4.3.1 13.4.3.2 13.4.3.3 13.4.3.4 13.4.3.5 13.4.3.6 13.5 13.5.1 13.6 14

14.1 14.2 14.2.1 14.2.2 14.2.3 14.3 14.4

14.5

Chemical Composition  397 Nutraceutical Composition  398 Dietary Fiber  398 Phenolic Content  398 Applications  399 Cocoa Juice  399 Cocoa Alcoholic Products  399 Pectin  400 Marmalade  400 Cocoa Jelly  401 Other Products  401 ­Technological Properties of Cocoa By‐products  402 Water (WHC)‐ and Oil (OHC)‐Holding and Swelling Capacities (SWC)  402 ­Concluding Remarks  402 References  403 Emerging and Potential Bio-Applications of Agro-Industrial By-products Through Implementation of Nanobiotechnology  413 Hayde Azeneth Vergara-Castañeda, Gabriel Luna-Bárcenas, and Héctor Pool ­Introduction  413 ­Green Synthesis of Metallic Nanoparticles Mediated by Agro-Industrial Wastes  414 Gold Nanoparticles  417 Silver Nanoparticles  419 Quantum Dots  422 ­Agro-Industrial Wastes as Platforms for Biofunctional Nanocomposite Production  425 ­Nano-Drug Delivery Systems for Encapsulation, Protection, and Controlled Release of Bioactive Agents Extracted from Agro-Industrial Wastes  431 ­Concluding Remarks  435 References  436 Index  445

xiii

xv

List of Contributors J. Abraham Domínguez-Avila Cátedras CONACyT‐Centro de Investigación en Alimentación y Desarrollo, A.C., Sonora, México Xochitl Aparicio-Fernandez Centro Universitario de los Lagos, Universidad de Guadalajara, Lagos de Moreno, Jalisco, México Jesus F. Ayala-Zavala Departmento de Tecnologia de Alimentos de Origen Vegetal, Centro de Investigacion en Alimentacion y Desarrollo, A.C., Hermosillo, Sonora, México Rocio Campos-Vega Programa de Posgrado en Alimentos del Centro de la República (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autónoma de Querétaro (UAQ), Querétaro, México María Dolores del Castillo Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación (CIAL) (CSIC-UAM), Campus de la

Universidad Autónoma de Madrid, Madrid, Spain Eduardo Dellacassa Departamento de Química Orgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay Paulo Henrique Machado De Sousa Institute of Culture and Art, Federal University of Ceará, Fortaleza, Brazil Adriana Maite Fernández-Fernández Departamento de Ciencia y Tecnología de Alimentos, Facultad de Química, Universidad de la República, Montevideo, Uruguay Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación (CIAL) (CSIC‐UAM), Campus de la Universidad Autónoma de Madrid, Madrid, Spain Raimundo Wilane De Figueiredo Department of Food Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil

xvi

List of Contributors

L. Gabriela Espinosa-Alonso Departamento de Biotecnología Agrícola, Alimentos Funcionales Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Sinaloa, Guasave, Sinaloa, México Marcela Gaytan-Martinez Posgrado en Ciencia y Tecnología de los Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Santiago de Querétaro, México Gustavo A. Gonzalez-Aguilar Departmento de Tecnologia de Alimentos de Origen Vegetal, Centro de Investigacion en Alimentacion y Desarrollo, A.C., Hermosillo, Sonora, México Fidel Guevara-Lara Departamento de Química, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Aguascalientes, México Diego Antonio Hernández-Montoya Programa de Posgrado en Alimentos del Centro de la República (PROPAC) Research and Graduate Studies in Food Science, School of Chemistry Universidad Autónoma de Querétaro (UAQ), Querétaro, México Teresa Herrera Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación

(CIAL) (CSIC‐UAM), Campus de la Universidad Autónoma de Madrid, Madrid, Spain Luz A. Herrera-Cazares Posgrado en Ciencia y Tecnología de los Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Santiago de Querétaro, México Amaia Iriondo-DeHond Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación (CIAL) (CSIC‐UAM), Campus de la Universidad Autónoma de Madrid, Madrid, Spain M. Liceth Cuellar-Nuñez Programa de Posgrado en Alimentos del Centro de la República (PROPAC) Research and Graduate Studies in Food Science, School of Chemistry Universidad Autónoma de Querétaro, Querétaro, México Guadalupe Loarca-Piña Programa de Posgrado en Alimentos del Centro de la República (PROPAC) Research and Graduate Studies in Food Science, School of Chemistry Universidad Autónoma de Querétaro, Querétaro, México Carlos Vladimir López-Rodríguez Programa de Posgrado en Alimentos del Centro de la República (PROPAC) Research and Graduate Studies in Food Science, School of Chemistry Universidad Autónoma de Querétaro (UAQ), Querétaro, México

List of Contributors

Gabriel Luna-Bárcenas Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV‐IPN), Querétaro, México Iván Luzardo-Ocampo Programa de Posgrado en Alimentos del Centro de la República (PROPAC) Research and Graduate Studies in Food Science, School of Chemistry Universidad Autónoma de Querétaro, Querétaro, México Geraldo Arraes Maia Department of Food Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil E.E. Martinez-Soberanes Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Canada Sergio Medina-Godoy Departamento de Biotecnología Agrícola, Alimentos Funcionales, Instituto Politécnico Nacional, Guasave, Sinaloa, México Alejandra Medrano-Fernandez Departamento de Ciencia y Tecnología de Alimentos, Facultad de Química, Universidad de la República, Montevideo, Uruguay

Nancy Viridiana Mendoza García School of Chemistry, Universidad Autónoma de Querétaro, Santiago de Querétaro, Qro, México Rana Mustafa Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Prairie Tide Diversified Inc., Saskatoon, Saskatchewan, Canada Karen Haydeé Nieto Figueroa Programa de Posgrado en Alimentos del Centro de la República (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autónoma de Querétaro, Santiago de Querétaro, Qro, México Francisco J. Olivas-Aguirre Departmento de Ciencias de la Salud, Universidad de Sonora (campus Cajeme), Ciudad Obregon, Sonora, México B. Dave Oomah (Retired) Formerly with Summerland Research and Development Centre, Agriculture and Agri‐Food Canada, Summerland, BC, Canada Maribel Ovando-Martínez Departamento de Investigaciones Científicas y Tecnológicas, Universidad de Sonora, Sonora, México Héctor Pool División de Investigación y Posgrado, Facultad de Ingeniería, Universidad Autónoma de Querétaro, Querétaro, México

xvii

xviii

List of Contributors

Giovana Matias Do Prado Department of Food Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil

Lucicleia Barros Vasconcelos Torres Department of Food Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil

Martin J. T. Reaney Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Prairie Tide Diversified Inc., Saskatoon, Saskatchewan, Canada, Guangdong Saskatchewan Oilseed Joint Laboratory, Department of Food Science and Engineering, Jinan University, Guangzhou, Guangdong, China

Timothy J. Tse Department of Plant Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Nágila Maria Pontes Silva Ricardo Department of Organic and Inorganic Chemistry, Fortaleza, Brazil Luiz Bruno De Sousa Sabino Department of Chemical Engineering, Federal University of Ceará, Fortaleza, Brazil Norma Julieta Salazar-López Programa de Ingeniería en Horticultura, Universidad Estatal de Sonora (UES), Hermosillo, Sonora, México Larissa Morais Ribeiro DA Silva Department of Food Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil

Maribel Valdez-Morales Departamento de Biotecnología Agrícola, CONACyT‐Instituto Politécnico Nacional, Guasave, Sinaloa, México Haydé Azeneth Vergara-Castañeda Department of Biomedical Sciences, Faculty of Medicine, Universidad Autónoma de Querétaro, Querétaro, México Abraham Wall-Medrano Instituto de Ciencias Biomedicas, Universidad Autonoma de Ciudad Juarez, Ciudad Juarez, Chihuahua, México W.J. Zhang Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

1

1 Cereal/Grain By-products Norma Julieta Salazar-López1, Maribel Ovando-Martínez2, and J. Abraham Domínguez-Avila3 1 2 3

Programa de Ingeniería en Horticultura, Universidad Estatal de Sonora (UES), Hermosillo, Sonora, México Departamento de Investigaciones Científicas y Tecnológicas, Universidad de Sonora, Sonora, México Cátedras CONACyT-Centro de Investigación en Alimentación y Desarrollo A.C., Sonora, México

1.1 ­Introduction By‐products are generated during harvesting and processing of different cereals worldwide as wheat, rice, maize, barley, oat, millet, sorghum, and other cereal grains, cereal crop residues, and cereal brans as food waste. The cereal crop residues are used for ethanol production from lignocellulosic biomass, animal feed, or burned in the soil with emissions that negatively impact the environment [1]. The milling of cereals is one of the main processing methods, and its objective is to obtain flour (endosperm) as the main product and generate as by‐products the bran, germ, protein, hull, broken grain, fiber, husk, and others; most of these cereal brans contain the pericarp, testa, aleurone and subaleurone layers, and part of the starchy endosperm. Depending on the cereal grain, the bran is around 3–30% of the kernel weight on dry basis [2]. During the eighties, the effluent from wheat starch–gluten production was high in biological oxygen demand (BOD). So, the wheat industry was concerned with pretreatments to control the wastewater effluent [3]. In this regard, wheat flour solubles (WFS) obtained by ultrafiltration and spray drying of an industrial gluten–wheat starch plant effluent performed well in yellow layer cake (50% whole egg substitution), cookies (up to 25%­substitution cookie formulation), and wieners (6% level) [3]. Nowadays,

Food Wastes and By-products: Nutraceutical and Health Potential, First Edition. Edited by Rocio Campos-Vega, B. Dave Oomah, and Haydé Azeneth Vergara-Castañeda. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

2

1  Cereal/Grain By-products

the  cereal food industry is interested in the recovery of starch, protein, lipids, ­dietary fiber, and bioactive compounds from these by‐products. Such recovery ­targets to produce nutraceutical ingredients for the production of functional foods. In order to achieve this aim, it is important to understand the biological properties and human health‐related benefits of the extracted bioactive ­compounds from the cereal grains waste and by‐products.

1.2  ­Global Production of Cereals and Crop Residues Annual global production (2008–2016) of cereals averaged about 3200 million tons of grains including wheat, maize, sorghum, barley, rice, oat, rye, and millet (Table 1.1) [4]. The global production of cereals increased 14.3% over the last nine years. During that period, the maize crop showed the highest increase (29.8%) in production compared to wheat, sorghum, barley, rice, oat, rye, and millet crops. Crop residues of cereals are a source of nutrients. The Pareto figure depicts the average cereal crop residues expressed as million‐tons of nutrients (2008–2016), indicating that over 80% of nutrients contained in crop residues come from rice (paddy), maize, and wheat crops (Figure 1.1). According to Santos et  al. [5], lignocellulosic biomass is the most abundant renewable resource, which could be used to obtain biofuels and with the advantage of not generating emissions of CO2 as fossil fuels. Regarding each million Table 1.1  Global production of cereals (millions of tons).

a

Wheat

Other cerealsa

Total productionb

995.3

793.5

306.0

2975.1

984.2

799.3

281.3

2947.1

898.3

1028.9

755.5

255.0

2937.7

929.0

1078.9

815.1

258.9

3082.0

2012

942.2

1080.0

793.8

259.0

3074.9

2013

947.2

1234.0

832.9

279.6

3293.7

2014

950.7

1254.1

859.7

287.3

3351.9

2015

949.9

1235.4

867.2

286.4

3338.9

2016

952.1

1291.9

881.2

276.7

3401.8

Year

Rice

2008

880.4

2009

882.3

2010 2011

Maize

 Other cereals include sorghum, barley, oat, rye, and millet.  Total production includes wheat, maize, sorghum, barley, rice, oat, rye, and millet production. Source: adapted from [4]. Reproduced with permission of The Food and Agriculture Organization Corporate Statistical Database.

b

1.2  ­Global Production of Cereals and Crop Residue

100

80

15

60 10 40 5 20

Rye

Oats

Millet

Sorghum

Barley

Maize

Wheat

0 Rice, paddy

0

Cumulative frequency (%)

Crop residues (million tons of nutrients)

20

Cereals

Figure 1.1  Crop residues of cereals expressed as millions of tons of nutrients (2008–2016). Source: adapted from [4]. Reproduced with permission of The Food and Agriculture Organization Corporate Statistical Database.

tons of rice, maize, and wheat produced, about 114, 186, and 119 thousand tons of biomass (dry matter), respectively, are burned (Table 1.2). In the analyzed period, biomass burned from rice, maize, and wheat crops increased by 8.5%. However, the maize crop generated higher quantity of burned dry matter compared to wheat and rice crops. On the other hand, statistical analysis showed that mainly four countries produced the highest proportion of cereal crop residues (2008–2016) (Figure 1.2). China and India are the two countries generating crop residues of cereals production with 672.7 and 604.7 thousand tons of nutrients, respectively, followed by Indonesia and United States of America with 472.9 and 455.9 thousand tons of nutrients, respectively. So, these statistics indicate that the challenge would be the search for alternative use of the cereal biomass from cereals crops (mainly maize, rice, and wheat). The aforementioned countries together with Vietnam, Russian Federation, Canada, Brazil, and others should study the use of cereal crop residues as a source of biofuels, nutrients, and phytochemicals, among others.

3

Table 1.2  Crop residues expressed as biomass burned (dry matter), in millions of tons. Biomass burned (dry matter) Year

Total production cerealsa

Rice

Maize

Wheat

Total biomass burned

2008

2669.2

104.3

193.0

98.4

395.7

2009

2665.8

103.2

190.0

99.8

393.1

2010

2682.7

105.5

196.5

95.9

397.9

2011

2823.1

106.2

204.8

97.9

408.8

2012

2815.9

105.9

213.9

96.8

416.6

2013

3014.1

107.3

222.3

97.1

426.7

2014

3064.6

106.4

221.8

98.1

426.4

2015

3052.5

105.2

220.6

98.5

424.3

2016

3125.2

104.6

226.9

97.8

429.4

a

 Total production of maize, rice, and wheat expressed as millions of tons; Biomass burned (dry matter) expressed as millions of tons. Source: adapted from [4]. Reproduced with permission of The Food and Agriculture Organization Corporate Statistical Database.

Egypt Poland México Turkey Australia Argentina Nigeria Cambodia United Kingdom Ukraine Myanmar Pakistan France Philippines Thailand Germany Bangladesh Brazil Canada Russian Federation Vietnam United States of America Indonesia India China 0

200

400

600

800

Annual average of cereal crop residues (Thousand tons of nutrients)

Figure 1.2  Global production of crop residues, in 2008–2016. Source: adapted from [4]. Reproduced with permission of The Food and Agriculture Organization Corporate Statistical Database.

1.3  ­Cereal Processing and Production of By-product

1.3  ­Cereal Processing and Production of By-products 1.3.1  Cereals Morphology and Composition Cereal grains belong to the Poaceae family [6] and includes wheat, rye, barley, oat rice, millet, corn, sorghum, and triticale (hybrid of wheat and rye); corn, rice, wheat, barley, oat, and rye are the most produced cereals around the world [7]. Cereal grains are consumed worldwide as staple food and most of their nutritional importance come from the grain composition [8]. The main structural components of cereal grains are the bran, germ, and endosperm, the latter found in high proportion [9, 10]. Brown rice has highest endosperm content among four cereal grains (corn, brown rice, wheat, and barley), followed by barley, corn, and wheat [9]. However, wheat had the highest bran content, while corn presented the ­highest germ content. The cereal bran consists of hemicellulose type cell walls rich in arabinoxylans and mixed‐linkage β‐glucan [6], cellulose, vitamins, and minerals [2, 9]. The endosperm is rich in starch, proteins, and small amount of dietary fiber, minerals [6, 9], and unsaturated fatty acids [11]. Finally, the germ contains lipids, proteins, and vitamins [8, 9]. The cell wall composition among cereal grains varies, especially in the polysaccharide composition and the morphology of the endosperm. The starchy endosperm plays an important role in the morphological form of the grains giving different shapes and sizes [6]. The cell wall morphology of wheat, barley, rye, and oat grains differs because of their arabinoxylans and β‐glucan ­content, both of them components of the cereal dietary fiber [12]. The staining techniques demonstrated that arabinoxylans are concentrated in nucellar epidermis and aleurone cells, while β‐glucan is concentrated in the subaleurone cells. In addition, cells in the starchy endosperm have a thinner cell wall compared to the aleurone cell layers. Apart from the aforementioned compounds, other bioactive compounds have been mostly determined in the cereal bran and germ [11, 13]. Starch, proteins, dietary fiber, and other bioactive compounds such as minerals, trace elements, vitamins, carotenoids, polyphenols, tocopherols, phytosterols, alkylresorcinols, betaine, choline, sulfur amino acids, phytic acid, lignans, and others are found mainly located in the bran and germ fractions of the grain [8, 11, 13–15]. Cereal grain composition has been related with the prevention or reduction of some types of cancer, cardiovascular diseases, diabetes, and obesity [8]. These health benefits attributed to cereal grains were first associated with the dietary fiber content, but recently, such benefits are also related to the bioactive compounds, which are unique in phytochemical composition. So, the knowledge of the distribution of a specific component in the grain structure is important to the food industry to recover specific compounds after grain processing [9]. However, such composition is affected by the processing method in the production of cereal‐based foods [16].

5

6

1  Cereal/Grain By-products

1.3.2  Cereal Grains Processing Most of the whole and refined cereal grains produced worldwide are subjected to specific processes to convert them into more desirable food ingredients with improved flavor, color, texture, appearance, and shelf life [17]. In addition, cereal grain processing is based on the composition of the main structural parts of the grain and its use in different cereal‐based foods [18]. The processing of grains in the food production chain includes milling, pearling, malting, and fermentation as the most important processes and others such as heat processing, extrusion, and puffing [7, 17, 18]. 1.3.2.1 Milling

This is the oldest way for cereal grains processing [19]. Since most of the inner volume of the cereal grains contains starch, the main purpose of milling is to separate the bran and germ from the starchy endosperm to reduce it into flour [18]. During this process, fractions of aleurone, pericarp, and testa are obtained, whereas some components such as dietary fiber and phytate are removed from the grains [17]. The milling grain process is classified in dry and wet milling, which could generate high amount of cereal grains waste and by‐products [8]. 1.3.2.2  Dry Milling

It is used to separate the seed coat, aleurone and subaleurone layers, and the germ from the white endosperm [7]. This process is mainly used in grains such as wheat, corn, rice, and barley [17]. Dry milling has been adopted in the maize food chain to produce refined endosperm products with different particle sizes and other by‐products depending on the degermination system [20]. The main products obtained from corn dry milling are grits, meals, and flour [17]. On the other hand, before the rice and barley milling process, pretreatments are used to separate the bran and husks from the grain (cleaning, shelling, or pulling), and then the remaining milled grain is considered as the endosperm to obtain the flour. In rice milling, husk, bran, and “brokens” are generated by the use of abrasive scouring or pearling [17, 18]; bran and broken grains are the main by‐products [21, 22]. Nowadays, dry milling is performed in tempering–degerming systems to aid fractioning [19]. With tempering, the grain is cleaned, adjusted to certain moisture content depending on the grain, and placed in a tempering bin. Later, the grains are processed in a degerminator to take off the pericarp and germ from the endosperm using crude abrasion. Finally, these grain components are separated by aspirators and gravity tables [17]. 1.3.2.3  Wet Milling

Wronkowska [23] defines this process as the separation of the main components of cereal grains through physical, chemical, biochemical, and mechanical

1.3  ­Cereal Processing and Production of By-product

­ perations. Wet milling is generally used for corn and wheat; however, it can be o used in the processing of other cereals such as sorghum, barley, oats, or rice. In general, this process is used to separate starch, germ, bran, and gluten [7], ­especially to extract the highest amount of undamaged starch granules, and generate germ, bran, and gluten as by‐products in cereal grains [8]. Bran and germ are the by‐products generated in high amount during corn wet milling, followed by the gluten and steep liquor [8]. Additionally, with the corn wet milling, starch, syrups, and dextrose are obtained as food ingredients [17]. The main by‐products are starch fractions and gluten in wet milling wheat, after the formation and agglomeration of gluten, and following separation of starch from this gluten mass by water washing [24]. The use of wet milling has been increasing especially to obtain compounds used in the production of industrial ethanol; however, it is important to take into account use of the by‐products generated by this process [23]. For example, functional soluble protein‐fiber products have been obtained from cereal grains using enzymatic starch digestion, ultrapurification, and concentration. The high‐protein and high fiber products from cereal grains can be dissolved in water and used to improve the nutritional and ­functional properties of a wide range of products, including food bars, soups, baked goods, breakfast cereals, sport drinks, and health‐promoting foods and beverages [25]. 1.3.2.4 Pearling

This technology is well known by its application in rice milling as mentioned above. However, it is also applied before durum wheat milling and is also known as debranning [7, 26]. Pearling is an abrasive process to remove the testa and pericarp, aleurone and subaleurone layers, and the germ of the grain. The grain obtained by this process can be converted into flour by roller milling. The abrasion helps to reduce the microbial load and the concentration of contaminants such as mycotoxins and heavy metals [26]. In the case of barley, pearled barley has been used as rice extenders and it can be milled for its application in bakery, pasta, and other products where its β‐glucan content is required in the food industry. Despite this, barley pearling should be improved to avoid altering the physical properties of the grain, as well as the particle size of the flour after milling [27]. The same concern applies to pearled wheat, because during this process, the generated wheat fractions differ in composition due to decreasing particle size of each fraction, presumably because of reduced enzyme activity by pearling of the bran [26]. This process in pearled barley is important to recover different grain fractions with unique composition [28]. Additionally, pearling also offers the opportunity to decrease the free fatty acids and lipase activity from the wheat bran, improving the storage stability of the bran [29]. The tangential abrasive dehulling device (TADD) was designed to gradually remove (abrade) layers from

7

8

1  Cereal/Grain By-products

barley and sorghum and simultaneously measure grain hardness. The abrasive hardness index of 31 sorghum samples ranged from 5 to 12.8 with extraction rates from 69 to 98% [30]. Several iterations of this device have been developed, including batch and industrial scale machinery used in many countries to dehull cereal grains [31]. 1.3.2.5 Malting

This is another process for cereal grains used in the production of beer and other type of alcoholic beverages through the steeping, germination, and kilning of the grains [7, 18]. Malting is induced by many complex biochemical processes, where cereal cell wall, proteins, and starch granules are degraded and modified. The main purpose of this process is the production of enzymes essential for the degradation of the compounds aforementioned. The enzymatic degradation of the cereal endosperm produces soluble peptides and amino acids, which are substrates for the synthesis of proteins and the growing embryo [32]. Barley is the most common cereal grain used in this process, especially for the brewing ­industry. During malting, barley is steeped to ensure good water absorption by the grain. Later, germination helps to maintain the embryo growth, enzyme synthesis, and limited endosperm breakdown. An incomplete germination process is applied, where barley kernel endosperm is enzymatically degraded. As a result of this degradation, the cell wall of the barley endosperm is degraded and the starch granules are released from the endosperm matrix. As mentioned, during malting, the germination process ensures a physical and biochemical change into the grain, which is later stabilized by drying; finally, the kilning ensures product stability [33]. This process has also been applied to common wheat [32], rice [34], sorghum, and buckwheat [35]. 1.3.2.6 Fermentation

Fermentation is a process carried out since antiquity for the conservation and improvement of the organoleptic properties of food. This consists of controlled processing realized by different microorganisms (fungi, lactic acid bacteria, and yeasts) added or native to the food. The fermentation of cereals causes the rupture of grain structures and changes characteristic in texture, flavor, and smell, besides improving the accessibility of nutrients and phytochemicals [36, 37]. The fermentation of cereal by‐products enables generation of traditional foods such as ­porridges, slurry, ogi, and alcoholic beverage, breads and different foods based on underutilized cereals [36, 37]. Currently, fermentation is used to produce functional metabolites from cereal by‐products; for example, the fermentation of wheat bran and rice bran improves the bioaccessibility of their phenolic compounds, mainly ferulated compounds, and promotes the growth of butyrogenic bacteria and colonic health benefits [38, 39].

1.4 ­Cereal Grains By-product

1.3.2.7 Others

Among other cereal grain processes, in pre‐milling rice, also known as husking, the awns of the paddy are separated from the rice grain. The efficiency of husking depends on the tightness of the husk bound to the rice variety and grain humidity. Other process for rice grains is the polishing, performed by a mild fraction or abrasion, where under gentle brushing, the remaining bran in the cereal grain is removed to improve grain translucency. On the other hand, a grading process separates rice pieces by sieving and air aspiration. In the case of oat grains, before milling, other processes such as thermal treatment and dehulling are used to ­produce naked caryopses known as groats [7]. In respect to corn, the grains are submitted to dry‐grind process, where the whole grains are ground into a coarse powder and fermented for ethanol production [40, 41]. Flaking is another process where oat groats are flaked. This process involves cleaning, heat treatment, dehulling, cutting, and flaking, all of them used to deactivated enzymes and avoid breakage of the oat groat produced by rolling oats [42]. Heat treatment primarily used to deactivate lipase activity in the commercial production of oat flour also influences the starch and protein components. Conditioning (steam injection at 96–100 °C) of oat groats alters protein solubility, lipase activity, and pasting and thermal characteristics [43]. Different processes can be applied to the main cereal crops worldwide depending on the cereal grain morphology and structure, as well as composition, to obtain bran, germ, gluten, oil, hull, and others. Cereal processing will depend on the cereal fraction of interest and the targeted food application of the grain. However, it is important to consider that this cereal processing will produce waste and by‐products, which could be related to environmental problems and losses to the food industry and farmers. So, it should be important to consider the nutritional compounds present in these by‐products, to take advantage and recover them to increase the added value.

1.4 ­Cereal Grains By-products During cereal grain processing, recovered by‐products may have functional and nutritional attributes [28] applicable not only for animal feed. Among the main cereal grain by‐products obtained with different processing methods are the bran, germ, protein, hull, fiber, husk, and others (Table 1.3). Most of the by‐products generated by the cereal processing are germ and bran, the latter constituted by aleurone and subaleurone layer, pericarp, and endosperm [9]. These fractions are sources of insoluble and soluble dietary fibers, oil, and other phytonutrients as reported in wheat, corn, and rice [44]. Bran (25% of the grain weight) is the most important wheat fraction, and it includes the starchy endosperm and aleurone

9

10

1  Cereal/Grain By-products

Table 1.3  Main cereal grains processing by-products. Cereal

Processing

By-products

References

Wheat

Dry milling

Bran (25% of wheat grain), germ (2–3% of wheat grain)

[8, 15, 44, 45]

Wet milling

Starch, fiber, gluten protein

[23]

Corn

Rice

Oat

Barley

Malting

Bran, starch, protein

[32]

Pearling

Bran (7–15% of wheat grain)

[26]

Dry milling

Bran (6–7% of corn grain), distiller’s dried grains (DDG), distiller’s dried with solubles (DDGS), distiller’s solubles

[7, 8]

Wet milling

Gluten feed, gluten meal, fiber (8–11% of corn grain), germ oil, sleeping solids, germ meal, molasses, liquefied corn product, condensed fermented corn extractives, hydrolyzed protein

[7, 8, 23]

Dry milling

Paddy (70% of rice grain), husk (20%), bran (8–12%), germ (2%), oil from bran (18–22% of the bran), bran layers, fine brokens plus bran (brewer’s rice)

[8, 15, 46]

Wet milling

Hull, bran, oil from rice bran

[23]

Dry milling

Broken rice (88% starch), maltodextrin.

[22]

Malting

Fiber

[34]

Pearling

Husk (20% of the rice grain)

[46]

Dry milling

Bran

[15]

Wet milling

Bran

[23]

Pearling

Bran

[42, 47]

Dry milling

Bran, germ

[15]

Wet milling

Fiber (8% of de barley grain), hull, protein

[23, 48]

Malting

Brewers’ spent grain (85% of total by‐products)

[9, 15, 49]

Pearling

Hull (30–49% of the barley grain)

[15, 26, 50]

Note: The percentage of each by‐product was not found in all cereal grains.

layers. Wheat bran fraction is generally used for feed products [45], but it represents a good source of ferulic acid, β‐glucan, arabinoxylans, cellulose, lignin, sterols, vitamin B, and minerals [15, 44, 45]. On the other hand, rice bran fraction, also used as animal feed, contains lipids, fiber, protein, steryl ferulate esters

1.5  ­Nutraceutical from Cereal/Grain By-product

(­oryzanols), polyphenols, and tocopherols [15, 46]. In the case of corn, its by‐­ products represent a source of proteins, oil, fiber, vitamins, and minerals; however, these compounds are being consumed only by animals [7, 40, 41]. Whole stillage of corn generates wet distillers’ grains, condensed distillers’ solubles and wet distillers’ grains with solubles and dried distillers’ grains in ethanol production [40]. These fractions represent a source of protein, fat, minerals, vitamins, and starch [41, 51]. About other by‐products, the germ fraction of cereal grains processing also ­represents a source of phytonutrients. For example, rice germ is a source of vitamin E as α‐tocopherol, vitamins B1, B2, and B6, dietary fiber, and γ‐aminobutyric acid (GABA) [46]. Besides the rice germ, brewer’s rice generated during rice dry milling also has nutritional importance; however, it is used as animal feed and brewing material. Among the compounds found in this fraction are carbohydrates, protein, oil, minerals, fatty acids, and bioactive compounds such as γ‐oryzanol, phytic acid, vitamin E, polyphenols, and dietary fiber [46]. Broken rice is a source of starch and maltodextrin, which has healing application [22]. Besides, rice by‐products obtained by controlled debranning can be used for ­production of probiotic strains and promote a healthy alternative [21]. In other processes such as malting and brewing, the brewer’s spent grain, obtained from the residual solid fraction of barley malt generated after the production of wort, is rich in protein and generally used in animal feed as a good source of protein and fiber [33]. This by‐product also contains phenolic acids such as p‐coumaric acid, ferulic acid, hydroxycinnamic acid, caffeic acid, and tocols, as well as arabinoxylans and β‐glucans [15, 33, 49]. In addition, the pearled barley fractions also contain starch, protein, soluble and insoluble dietary fibers, β‐glucans, tocopherols, tocotrienols, and polyphenols, all with nutritional ­significance [28, 50]. Despite the use of by‐products as animal feed, it is necessary to add value to cereal grain by‐products. Because of this, the milling industry is seeking to increase application of these by‐products in the pharmaceutical and food industry as nutraceutical ingredients and functional foods due to the presence of bioactive compounds and in other agroindustries due to the presence of fiber, protein, oil, minerals, and starch [16]. So, it is important to study the nutraceutical and functional ingredients contained in these by‐products for their extraction, considering the cereal processing, by‐products generated, and phytonutrients profile.

1.5  ­Nutraceutical from Cereal/Grain By-products Most of the cereal grain by‐products represent a source of different phytonutrients and bioactive compounds, which could be used in the development of food ­products or extraction of nutraceutical ingredients. Nowadays, consumers are

11

12

1  Cereal/Grain By-products

more interested in the consumption of products with human health‐related ­benefits [52]. Therefore, it should be important to classify these compounds based on the main structural components of cereal grain by‐products, to understand their localization and concentration as described in Table 1.4.

1.5.1  Classification of Nutraceutical Ingredients in Cereal By-products 1.5.1.1 Polyphenols

The bran layer as a protective tissue is a rich source of polyphenols in cereal grain by‐products [53, 60]. Polyphenols are also known as potent antioxidants and can be classified according to their structure in phenolic acids (benzoic and cinnamic acids), flavonoids (anthocyanidins, quinones, flavonols, flavones, flavanones), and tannins [14]. Some of them were identified in cereal grain by‐products (Table 1.4). 1.5.1.1.1  Phenolic Acids  Most phenolic acids are bound, mainly linked to polysaccharides by ester bonds, to lignin by ether bonds and proteins. However, there are soluble phenolic acids (free, soluble esterified and glycosylated forms) that contribute to the flavor and antioxidant capacity [60]. Among the phenolic acids found in cereal grain bran, aleurone, and husk are p‐hydroxybenzoic acid, chlorogenic acid, syringic acid, vanillic acids, vanillin, p‐coumaric acid, ferulic acid, salicylic acid, and caffeic acids [56]. Ferulic acid is mostly found in the bran linked to the cell wall polysaccharides (hemicellulose) or to lignin through ester and ether bonds [53], while vanillic acids and p‐coumaric acids are found in the husk [8]. Additionally, p‐coumaric acid could indicate the presence of aleurone cell walls in cereal grain by‐products [56]. On the other hand, ferulic acid may be responsible for the antioxidant properties of the cereal grain fractions [56]. Wheat bran contains high levels of phenolics (two to three folds), those in their respective flours depending on wheat cultivars. The phenolic‐rich kernel tissues (e.g. bran and shorts) are separated from the flour stream as a result of the milling process [61]. 1.5.1.1.2 Flavonoids  Among flavonoids, anthocyanins are located in a specific

layer of the cereal grain. In wheat, anthocyanins are concentrated in the pericarp and aleurone layer of purple and blue wheat grain varieties, respectively. The main anthocyanins found in purple wheat are peonidin and cyanidin glycosides [52]. In blue wheat, delphinidin‐3‐O‐rutinoside and cyanidin‐3‐O‐rutinoside, cyanidin‐3‐O‐glucoside, delphinidin‐3‐O‐glucoside, and peonidin‐3‐O‐rutinoside were detected. Brewers’ spent grains contain flavonoids [59].

1.5.1.1.3 Tannins  These compounds are covalently linked to the cell wall polymers as cellulose, hemicellulose, lignin, pectin, and rod‐shaped structural proteins. Since they are in bound form, tannins cannot be digested by human  enzymes, remaining intact during the digestion process in the upper

Table 1.4  Classification of nutraceutical ingredients in some cereal grain by-products. Localization (by-product)

Cereal

Nutraceutical ingredients

References

Bran

Wheat

Total dietary fiber (45–56%), soluble dietary fiber, insoluble dietary fiber, alkylresorcinols (0.27%), ferulic acid monomer (0.5–0.7%), ferulic acid dimer (0.8–1%), sinapic acid (0.02%), p‐coumaric acid (0.01%), flavonoids (28 μg/100 g), total β‐glucans (2–2.6%), total arabinoxylans (10–30%), lignin (5.6%), sterols, protein (13–22%), phytosterols (0.16–0.17%), α‐linoleic acid (0.16%), starch (13–27%), cellulose (6.5–11%), lipids (1–4%), minerals (3.4%), betaine (0.87%), vitamins (0.04%)

[26, 45, 53–55]

Durum wheat

p‐Hydroxybenzoic acid (281–897 μg/g), chlorogenic acid (0.8–1.7 μg/g), syringic acid (4.83–46.2 μg/g), vanillic acid (8.8–53.2 μg/g), vanillin (5.08–46.7 μg/g), p‐coumaric acid (17.3–147 μg/g), ferulic acid (421–2102 μg/g), salicylic acid (24.3–114 μg/g), fiber content (10–35%)

[56]

Wheat: roller‐ milled and pearled fractions

Content among red, white, yellow, purple and blue wheat types: Protein (12–17%), total dietary fiber (26–34%), β‐glucan (0.66–2%), free phenolic acids (4–18 mg/kg), total anthocyanins (140–271 mg/kg), lutein (1.6–3 mg/kg), zeaxanthin (0.28–0.91 mg/kg)

[52]

Barley

Starch (32.31%), protein (16.23%), fat (8.57%), ash (2.79%), total dietary fiber (35.10%), soluble dietary fiber (14.67%), insoluble dietary fiber (20.43%), total β‐glucan (4.78%)

[50]

Rice

Protein (10–17%), crude fat (5–20%), crude fiber (7–19%), calcium (0.08–1.4%), phosphorus (1.3–2.9%), cellulose (30%), hemicellulose (20%), lignin (20%), γ‐oryzanol (0.93–13.8 mg/g), tocopherols (27–770 μg/g), tocotrienols (17–460 μg/g), total phenolics (14–20 g GAE/kg), total anthocyanins (55 mg/g), total proanthocyanidins (67 mg/g), protocatechuic acid (168–5777 μg/g), vanillic acid (34–1568 μg/g), p‐coumaric acid (424–517 μg/g), ferulic acid (20–1995 μg/g), 4‐hidroxibenzoic acid (427–673 μg/g), caffeic acid (111–157 μg/g), sinapic acid (2039–2544 μg/g)

[46]

(Continued )

14

1  Cereal/Grain By-products

Table 1.4  (Continued) Localization (by-product)

Cereal

Nutraceutical ingredients

References

Corn

Total phenolic (1538–1925 mg GAE/100 g, dw), total flavonoids (228–624 mg CE/100 g, dw), β‐carotene (35 μg/g, dw), tannins (250 mg CE/100 g, dw)

[57]

Oat

Total arabinoxylans (3.5%)

[58]

Wheat

Total phenolic (987–1862 mg GAE/100 g, dw), total flavonoids (316–682 mg CE/100 g, dw), β‐carotene (15 μg/g, dw), tannins (150 mg CE/100 g, dw)

[57]

Rice

Total phenolic (555–1013 mg GAE/100 g, dw), total flavonoids (180–674 mg CE/100 g, dw), β‐carotene (5 μg/g, dw), tannins (100 mg CE/100 g, dw)

Corn

Total phenolic (676–1235 mg GAE/100 g, dw), total flavonoids (257–547 mg CE/100 g, dw), β‐carotene (20 μg/g, dw), tannins (300 mg CE/100 g, dw)

Aleurone

Wheat

Arabinoxylans (24.3%), β‐glucans (23.9%), cellulose (3%), ferulic acid monomer (0.66–0.82%), ferulic acid dimer (0.03– 0.1%), sinapic acid (0.03%), p‐coumaric acid (0.02%), flavonoids (8 μg/100 g), lignans (7 μg/100 g), minerals (12%), alkylresorcinols (0.17%), betaine (1.5%), vitamins (0.03%)

[55]

Husk

Rice

Protein (2–4%), crude fat (0.3–1%), crude fiber (30–54%), calcium (0.04–0.21%), phosphorus (0.0–‐0.08%), cellulose (38%), hemicellulose (20%), lignin (22%), γ‐ oryzanol (0.06–0.16 mg/g), gallic acid (5–10 μg/g), protocatechuic acid (6–24 μg/g), p‐hydroxybenzoic (10–11 μg/g), chlorogenic acid (4–11 μg/g), vanillic acid (7–27 μg/g), syringic acid (2–12 μg/g), p‐coumaric acid (4–33 μg/g), ferulic acid (18–64 μg/g), total phenolic (776–1060 mg GAE/100 g, dw), total flavonoids (143–308 mg CE/100 g, dw), β‐carotene (20 μg/g, dw), tannins (200 mg CE/100 g, dw)

[46, 57]

Rice

Total arabinoxylans (8.36–9.24 %)

[58]

Oat

Total arabinoxylans (8.79%)

Germ

Hull

1.5  ­Nutraceutical from Cereal/Grain By-product

Table 1.4  (Continued) Localization (by-product)

Brewers’ spent grain

Fermentation material/wet milling

Cereal

Nutraceutical ingredients

References

Wheat

Total fat (6.61%), saturated fatty acids (29.78%), monounsaturated fatty acids (14.53%), polyunsaturated fatty acids (29.78%), n‐3 polyunsaturated fatty acids (5.18%), n‐6 polyunsaturated fatty acids (50.51%), total phenols (284 mg GAE/100 g, fw), flavonoids (13.6 mg QE/100 m, fw)

[59]

Rice

Protein (9.01%), crude fat (1.95%), calcium (0.013%), phosphorus (0.316%), γ‐oryzanol (14.2 mg/g), tocopherols (3.4 μg/g), tocotrienols (3.25 μg/g), gallic acid (26 μg/g), vanillic acid (2.87 μg/g), syringic acid (5.87 μg/g), p‐coumaric acid (7.13 μg/g), ferulic acid (36.42 μg/g), caffeic acid (5.32 μg/g)

[46]

Barley

Fiber (8%) → starch (17.2%), NDF (66.2%), β‐glucan (0.5%) Cell wall (11.1%) → starch (14.3%), NDF (42.7%), β‐glucan (4.5%) Fermentation material without wet fractionation step (92%) → starch (62.2%), NDF (15.1%), β‐glucan (3%) Fermentation material with wet fractionation step (80.9%) → starch (68.7%), NDF (11.3%), β‐glucan (2.8%)

[48]

GA, gallic acid equivalents; QE, quercetin equivalents; CE, catechin equivalents; dw, dry weight; fw, fresh weight; NDF, neutral dietary fiber

gastrointestinal tract, until they reach the colon, where they can be fermented by the microbiota [62]. The levels of these compounds in brown rice decrease with the degree of milling because of the removal of bran during this process [62]. This indicates that tannins are concentrated in the bran fraction of cereal grains such as corn (Table 1.4). However, tannins also are detected in wheat, rice, and corn germs, as well as in the rice husk. Pigmented and wild cereal grain types generally contain high tannin levels. For example, proanthocyanidins absent in common rice are present in red and black rice genotypes. Similarly, naked barley and two‐row barley contain significantly lower amounts of condensed tannins than  six‐row barley varieties. Barley tannin–protein interaction is critical in brewing; high tannin barley is often responsible for the undesirable nonbiological haze in beer [63].

15

16

1  Cereal/Grain By-products

1.5.1.2 Carotenoids

The content of carotenoids in cereal and cereal by‐products is a function of the type of cereal and variety, growing conditions, type of by‐product, and the method of extraction and quantification of carotenoids [57]. Lutein is more concentrated in the endosperm than in the bran of different pigmented wheat types. In contrast, zeaxanthin values change according to the wheat variety [52]. Smuda et al. [57] provided carotenoid contents of some cereal milling by‐products, where it is observed that the corn germ meal has higher carotenoid content (57.9 μg/g) ­compared to the corn bran and corn germ. In addition, the by‐products of corn milling (corn germ meal and bran) contain a higher content of carotenoids ­compared to the by‐products of the milling of rice (bran, germ, and husk) and wheat (bran, germ, and short). 1.5.1.3  Dietary Fiber

Dietary fiber is an important nutrient in the human diet. This includes non‐starch polysaccharides and consists mainly of cell wall‐associated arabinoxylan, β‐glucan, and arabinogalactan, as well as cellulose to a lesser amount. These ­compounds are located in the cell wall of the cereal grain, consisting of the outer layers, seed coat, and the pericarp part of the insoluble dietary fiber [42]. The insoluble dietary fiber fraction includes lignins, cellulose, and some hemicellulose, while the soluble dietary fiber is formed by pectin, gums, mucilage, and the rest of hemicellulose [8]. According to Table  1.4, cereal grains bran and rice husk  represent a good source of total dietary fiber. As part of the dietary fiber, arabinoxylans and β‐glucan are important from the nutritional point of view [45]. 1.5.1.3.1 Cellulose  This is a vital component of the plant cell. It is the dominant

component of all cell wall in cereal grains, and its structure consists of a linear homopolymer of β‐(1‐4)‐linked glucose units. Chemical or enzyme hydrolysis can convert cellulose into soluble oligosaccharides as a source of prebiotics [51]. This polysaccharide was detected in wheat, barley and rice brans, and rice husk (Table 1.4).

1.5.1.3.2 Arabinoxylans  These are the main structural component of the cell

wall of bran and are extracted from destarched and deproteinized bran. Their content in the bran depends on the cereal grain (Table  1.4). Structurally, arabinoxylan consists of a linear β‐D‐(1‐4)‐linked xylopyranose backbone, which can be substituted at C(O)‐2, C(O)‐3, or both in different positions. The principal substituent is single α‐l‐arabinofuranose linked to the xylan at C(O)‐1 [53]. Arabinoxylans with high substitution are mainly soluble in water and do not form aggregates; however, if the arabinoxylans are low substituted, during the dissolutions there is a tendency to form aggregates. In addition, the arabinoxylan’s

1.5  ­Nutraceutical from Cereal/Grain By-product

structure occasionally contain arabinofuranosyl residues esterified at C‐5 with ferulic acid compound, which affect the extraction of arabinoxylans and antioxidant properties in wheat. The insoluble forms of arabinoxylans within the  cell wall contain higher levels of bound phenolic acids through oxidative cross‐links, not allowing its extraction [64]. 1.5.1.3.3  β-Glucan  It is mainly located in the aleurone layer of cereal grains

[50, 53], and its content depends on the cereal grain by‐product (Table 1.4). They are water soluble and their structure consists of cellotriose (DP3) and cellotetraose (DP4) units linked by and β‐1–3 linkages. The DP3/DP4 ratio is used to identify different types of β‐glucans and is also related to the solubility of this compound [64]. Oats are a source of β‐glucans (2.2–7.8 g/100 g), which have been associated with the control of diabetes and blood cholesterol levels, so they have been proposed for obtaining functional foods, participating as substituents of the fat of yogurt and cheese, and in the preparation of products for people intolerant to lactose and cholesterol problems  [65]. In this regard, Patsioura et al. [65] investigated the recovery of β‐glucans from oat mill waste by ultrafiltration optimization, and they achieved to  obtain up to 600 mg/L of β‐glucans; however the area of opportunity is the ­separation of the β‐glucans and proteins.

1.5.1.4 Prebiotics

Prebiotics, a specific substrate for the intestinal bacteria, are defined as a selective fermented ingredient that allows specific changes in the composition and activity of the intestinal microbiota resulting in benefits for the host well‐being and  health. Prebiotics are nondigestible carbohydrates as the polysaccharides and oligosaccharides. Cereal grains fractions contain polysaccharides and ­oligosaccharides with promising use as prebiotics. The dietary fiber (cellulose, β‐glucan, α‐glucan, arabinoxylans) and resistant starch associated with dietary fiber present in wheat bran represent an option for prebiotics [51]. 1.5.1.5  Lipids and Fatty Acids

Lipids and fatty acids are found as components of intercellular membranes, spherosomes, starch, and protein bodies in different cereal grains by‐products. The most common lipids found in the brewers’ spent grains are triglyceride, followed by free fatty acids. The total lipids found in wheat brewers’ spent grains was higher than that found in malt samples. Among the fatty acids detected in this by‐product are linoleic acid, palmitic acid, and oleic acid, as well as linoleic acid, stearic acid, myristic acid, vaccenic acid, arachidic acid, 11‐eicosenoic acid, behenic acid, and lignoceric acid [59]. In rice husk, the most important fatty acids  are linoleic, stearic, oleic, and palmitic acids [40]. On the other hand,

17

18

1  Cereal/Grain By-products

Hemdane et al. [54] reported that finer bran from wheat milling by‐products had a higher lipid content, maybe because this fraction contains germ remnants or a higher amount of aleurone. 1.5.1.6 Proteins

Cereal proteins are found along the cereal grain and are classified in four types: albumins, globulins, prolamins, and glutens, soluble in water, dilute salt solutions, 70% alcohol, and dilute alkaline solutions, respectively. In cereal grain by‐ products, proteins are concentrated in the bran (11–15%) and are storage proteins [9]. The protein composition among wheat milling by‐products differs because of high or low endosperm contaminations in the fractions. From this, the amino acids profile is different between different bran layers and endosperm [54]. 1.5.1.7 Starch

Starch is one of the main components of bran depending on the degree of milling. Starch from bran can be hydrolyzed to glucose and used as sugar feedstock in the fermentation process of lactic acid production, succinic acid, ethanol, and butanol [53]. In the case of corn and barley during the wet milling process, starch is the component found in high amount because of the endosperm [48, 66]. Nevertheless, starch is also found in wheat and barley bran (Table 1.4).

1.6  ­Health Potential of Cereal/Grain By-products As previously discussed, cereal by‐products are rich in various bioactive compounds that have health‐promoting properties. Their role in some common diseases has been thoroughly studied in animal and human models, with evidence consistently showing favorable results against them (Figure  1.3). The following section aims to provide an overview of recently published results that describe diverse health effects of cereals and their by‐products; the specific compounds responsible for the effect are mentioned, and the mechanism of action is also ­provided when available.

1.6.1  Non-Communicable Diseases 1.6.1.1  Dyslipidemia and Cardiovascular Effect

Zhang et al. [67] fed 48 male C57BL/6J mice a non‐supplemented diet high in fat and cholesterol, or the same diet supplemented with 0.8% oat fiber or 0.8% wheat fiber, for a 12‐week period. Diets with such characteristics are notorious for strongly promoting obesity, cardiovascular disease by altering the serum lipid

1.6  ­Health Potential of Cereal/Grain By-product Anti-obesity Leptin sensitivity ↓Weight gain,

Antioxidant72, 78, 79 Stabilization ROS

↑Insulin67-69, 73, 74 ↓Diabetes73, 74

↓Human hepatocellular carcinome77

↓Hematological cancer76

↓Colon carcinome75 Improves gut microbiota73

Cereal by-products

Anti-inflammatory68, 72, 73, 78

Cardioprotective effects Anti-atherosclerotic68, 71

↓Lipid digestion and absorption70

Figure 1.3  Health potential of cereal/grain by-products. Reactive oxygen species (ROS).

­ rofile, and loss of insulin sensitivity (and other hormones) that later culminates p in diabetes. The authors reported that added cereal fiber mitigated the previously described negative effects of fat and cholesterol; specifically, it prevented weight gain and an increase in serum lipids, while also preventing loss of insulin and leptin sensitivity, all of which occurred in the non‐supplemented group. They also emphasized that oat bran performed better than wheat bran, suggesting that in addition to fiber, other components may have contributed, but this was not investigated. Further studies were performed by the same authors in apolipoprotein E (ApoE) knockout mice (ApoE−/−) [68]. ApoE a protein component of chylomicrons, LDL and other lipoproteins, are necessary to maintain serum lipid homeostasis. When ApoE is mutated or absent in murine models, the animals develop dyslipidemia when fed high fat diets, which is why this model can be used to test the antiatherogenic potential of dietary components or pharmaceuticals. ApoE−/− mice were fed the previously mentioned diets for 18 weeks, with results showing less aortic foam cells and atherosclerotic plaque in the fiber‐supplemented groups, in contrast to the non‐supplemented group. Differences were also found between both types of fiber, with oat fiber performing better (i.e. less plaque area) than wheat fiber. These results also correlated with an anti‐inflammatory effect exerted by both treatments. In humans, atherosclerotic plaque builds up and hardens (through calcification) slowly throughout decades of life and can become large enough to prevent blood flow and induce a myocardial infarction (commonly known as a heart attack); its development can be further exacerbated by systemic

19

20

1  Cereal/Grain By-products

inflammation promoted by dietary (and other) factors. In contrast, adequate ­dietary habits can prevent or delay its development. This indicates that a simultaneous anti‐inflammatory and anti‐atherosclerotic action can exert cardioprotective effects that could reduce the risk of cardiovascular disease. Taken together, these results [67, 68] suggest that cereal fibers may prevent obesity and related conditions, such as hormonal sensitivity, inflammation, and arterial plaque formation, all of them risk factors that promote the development and progression of two leading causes of mortality in modern societies, cardiovascular disease and diabetes. Han et al. [69] administered a high fat/high cholesterol diet (46% calories from fat, 1.0% cholesterol) supplemented with 0.8% wheat bran fiber or 0.8% oat fiber (containing 22% β‐glucans) to male C57BL/6J mice for a 24‐week period. Numerous significant effects were evident during and after the experimental period; for example, weight gain was more pronounced in the untreated high fat/ high cholesterol group compared to control group, but both cereal treatments mitigated this increase. This is indicative of an anti‐obesity effect exerted by fiber supplementation. Serum lipids, glycemia, insulinemia, and insulin sensitivity were all negatively affected by fat and cholesterol supplementation, but the treatments prevented these alterations by maintaining values similar to those of the control group. Consuming diets high in fat and/or cholesterol is increasingly ­common in modern times and leads to the aforementioned metabolic alterations, which are typically associated with obesity, cardiovascular disease, and diabetes. In addition, they are also strong promoters of hepatic disease, which was also evident under histological examinations of the liver. The fat/cholesterol diet promoted lipid accumulation in increased‐sized cells and inflammatory cell infiltration to this organ, which was mitigated by the fiber treatments. The authors suggest that the mechanism of action of their treatments is related to changes to the expression of genes related to lipid metabolism, such as sterol regulatory element binding protein (SREBP), peroxisome proliferator‐activated receptor alpha (PPARα) and gamma (PPARγ), liver X receptor alpha (LXRα), and others, according to additional experiments. Thus, the evidence suggests that oat and wheat fiber exert hepatic and overall health‐promoting effects, which are mediated through altered gene expression, biochemical changes, and tissue homeostasis. Gunness et al. [70] investigated the effect of wheat arabinoxylans (AXs) in large white male pigs that were fed Western‐type diets containing red meat and beef tallow. Models of Western diets seek to mimic dietary patterns of Western societies, including high intake of animal fats and proteins, alongside low intake of fruits, vegetables, fiber, and some micronutrients. Humans who consume such diets for extended periods (years or decades) have increased risk of obesity, cardiovascular disease, diabetes, and other diet‐related diseases. Supplementing a Western diet with cereals or their by‐products is therefore a useful way to evaluate

1.6  ­Health Potential of Cereal/Grain By-product

their potential beneficial effects, without drastically changing the overall dietary pattern. The animals used in this study were sacrificed after consuming the experimental AX‐supplemented diets for four weeks; the small intestine, gallbladder, and blood samples (jugular vein and hepatic portal vein) were then recovered. Circulating triacylglycerols (TAGs) and bile acids were significantly reduced in AX‐fed animals. TAG digestibility throughout the small intestine was lower and accompanied by reduced total bile acid concentration in the gallbladder, as well as the major bile acid present therein (hyodeoxycholic acid). Results of the study are believed to indicate changes in lipid digestion and absorption through different potential mechanisms. First, undigested fatty acids in the intestine increased from 4.0 to 9.6% in response to AX, presumably due to increased viscosity of the intestinal contents, and consequently lower TAG emulsification. This may induce lower lipid and caloric intake without consuming less food. Second, reduced bile acid production and concentration in the gallbladder suggests a change to a more hydrophobic bile acid profile (which is protective against gallstones), due possibly to altered expression of genes that regulate bile acid synthesis and transport. These findings collectively suggest that cereal‐derived AXs exert protective effects against obesity and cardiovascular disease while also maintaining gastrointestinal and hepatocholic health. Therefore, including AXs in the diet can be used to avoid consuming pharmaceutical compounds with similar effects, without negative side effects. Andersson et al. [71] analyzed the effects of oat consumption in LDL receptor (LDLR) knockout mice (LDLR−/−) that were fed Western‐type diets for six weeks. Diets contained a high energy percentage derived from fat (41% calories from fat), while oat supplementation was fixed at 30%. Results showed a significantly lower serum cholesterol and TAG concentration, which may have been related to an increased fecal excretion of cholesterol and bile acids. A transcriptome analysis of the jejunum revealed that lipid biosynthesis and regulation were among the most affected metabolic processes in response to oat consumption. Based on their findings, the authors propose that oats mitigate the negative consequences exerted by the high fat content of their experimental diet. Although these results are promising, a diet that consists of 30% oats may be difficult to be regularly consumed by humans, unless a strict vegetarian or vegan diet is followed. Nevertheless, this data suggests that oat consumption should be encouraged. Oats not only are rich in fiber but also contain avenanthramides, a representative class of polyphenolic compound of oats, which could also contribute to the favorable results documented by various authors. For example, Thomas et al. [72] analyzed the effects of avenanthramides in LDLR −/− mice. Similar to ApoE, LDLR is a membrane receptor that allows cellular uptake of lipids from serum lipoproteins; in its absence, serum lipids and lipoproteins are not adequately ­bioavailable by peripheral organs or by the liver, which leads to an abnormally

21

22

1  Cereal/Grain By-products

high serum lipid profile that promotes rapid atherosclerosis development. The animals used in this study were fed a high fat diet (43% energy from fat) that was supplemented with oats low or high in avenanthramides (8.8 and 480 mg/kg, respectively) for a 16‐week period. Once the experiment concluded, sections from the aortas were dissected and stained to visualize their lipid contents. Results showed that both oat treatments (low or high avenanthramides) prevented lipid deposition in the artery, maintaining a concentration that was numerically and statistically similar to mice fed a low fat control diet. However, the high avenanthramide oat treatment further reduced aortic lipid content to values significantly lower than all other diets, including the control. These effects were also related to microscopic lesions to the tricuspid valve of the heart, and all actions were evident even when serum cholesterol concentration was statistically similar among all groups. According to their results, the authors argue that the cardioprotective effects of oats are mainly due to the presence of β‐glucans and avenanthramides, and while the exact mechanism of action is unknown, it may be related to a combination of antioxidant and anti‐inflammatory actions. They also suggest that the effects of other minor components, such as phytosterols, tocopherols, and other types of phenolic compounds, cannot be ruled out and may also contribute to the overall effect. The Food and Drug Administration (FDA) provides a health claim for an association between consumption of diets high in oat meal, oat bran, or oat flour and reduced risk of coronary heart disease. The FDA has also acknowledged that the main active ingredient, in this respect, is the soluble fiber, β‐glucan [80]. 1.6.1.2 Diabetes

The effects of finger millet (Eleusine coracana) consumption (either 10% whole grain or 10% bran) were determined in LACA mice fed with high fat diets [73]. The overall outcome was positive for several parameters related to obesity and diabetes as affected by dietary fat. For example, the cereal treatment mitigated body weight gain with no effect on the amount of ingested food, suggesting that the animals ate until satiety, yet accumulated less fat. This effect may be due to changes in adipose tissue gene expression that prevented adipose accumulation in this organ and suppression of proinflammatory genes. The high fat diet impaired glucose uptake and altered the serum lipid profile, both of which remained within normal values in bran‐fed animals. Gut microbiome also changed, showing increase in populations of beneficial bacteria (Lactobacillus, Bifidobacteria, Roseburia, Akkermansia, and Bacteroidetes). Finally, most effects were found only in bran‐fed but not in whole grain‐fed animals, suggesting that bran is the most bioactive fraction of this cereal. This study demonstrates that the effects of finger millet bran are due to a number of actions on various tissues, which synergize to prevent obesity, diabetes, inflammation, and related conditions that negatively affect the health of an organism consuming high fat diet. Changes to the gut

1.6  ­Health Potential of Cereal/Grain By-product

microbiota are noteworthy, because the link between its composition and overall health has only been studied in recent decades, and they may be an important connection between dietary patterns and their systemic effects through the production of some bacteria‐derived molecules. Similarly, a rice bran enzymatic extract was used to supplement high fat diets (60% energy from fat) fed to male C57BL/6J mice [74]. Glycemia and insulinemia increased after 16 weeks in non‐treated mice, but rice bran extract returned these values to normal range. Adipocyte size increased in response to the high fat diet, while rice bran treatment mitigated this increase (anti‐obesity effect); furthermore, macrophage infiltration to this tissue was also mitigated (anti‐inflammatory effect). mRNA expression analyses revealed that adiponectin expression, but not leptin, was normalized by the treatments. Adiponectin and leptin are two white adipose tissue‐derived peptide hormones that maintain body weight homeostasis by regulating satiety (through actions in the central nervous system), long‐ term energy expenditure and storage (in muscle and adipose tissue), and other actions. Furthermore, adiponectin stimulates glucose uptake and catabolism, thereby exerting antidiabetic actions. Thus, rice bran enzymatic extract may exert favorable effects that contribute to the prevention of obesity, diabetes and chronic inflammation that occur when high amounts of fat are regularly consumed in the diet. 1.6.1.3  Anticancer Effect

The effects of cereals on malignant cells has also been studied. For example, a glycoprotein isolated from defatted rice bran was used against 26‐M3.1 cells derived from colon carcinoma of lung metastases in female BALB/c mice [75]. The mice were prophylactically treated with an intravenous dose of 0.5 or 5 mg/kg of rice glycoprotein before injection with malignant cells. The in vitro results showed that rice glycoprotein treatment promoted proliferation of healthy splenocytes, while malignant cells remained unaffected by the treatment. The in vivo results showed a dose‐dependent reduction in the number of developed lung metastases. The combined in vitro and in vivo data are indicative of an anti‐­ metastatic effect, which is mediated through natural killer (NK) cell activation (determined through additional experiments). It was therefore concluded that rice bran glycoprotein improves innate immunity and may be used as an anti‐ metastasis agent with no cytotoxicity or other side effects against healthy cells. This provides important evidence that advocates the use of rice bran as a source of anticarcinogens, although its mechanism of action was not studied, nor were the anticancer effects of rice bran consumption, suggesting the need for additional experimentation. A mixture of brown rice and rice bran fermented with Aspergillus oryzae was prepared to analyze their combined in vitro anticancer effect [76]. Jurkat cells

23

24

1  Cereal/Grain By-products

(human T lymphocytes originally isolated from an acute T cell leukemia patient) were incubated with 12.5–100 μL/mL of extract for 24 hours, or 12.5 μL/mL for up to 72 hours, to test the effectiveness of the extract. Results showed a statistically significant reduction in viability in doses 25 μL/mL, reaching up to 90% effectiveness at the highest dose. The lowest dose also exerted significant effects at 48 and 72 hours of incubation time. These results were further scrutinized by ­additional experiments to determine the possible mechanism of action of said cytotoxic effects. Results showed that the cells’ genomic DNA was fragmented after a 13hour incubation period, suggesting that cell death occurs through ­apoptosis rather than necrosis. This was confirmed by co‐incubating the cells with the treatment and with a pancaspase inhibitor, which significantly lowered the effectiveness of the brown rice treatment. Further evidence was provided to show that caspases were activated, as was the death receptor pathway; both mechanisms of action result in cell death through different signaling events. Based on the precise results, the brown rice and rice bran fermented with Aspergillus oryzae may potentially be considered a functional food that can be directed to hematological cancer patients; however, the active components have not been unequivocally identified. Tartary buckwheat bran (Fagopyrum tartaricum, L. Gaerth, FG) is a by‐product obtained during buckwheat flour production. Its antiproliferative activity against HepG2 cells (derived from a human hepatocellular carcinoma) was evaluated and correlated with the phenolic composition of the bran, considering both the free and bound phenolic fractions [77]. Phenolic compounds were found to be predominantly free (94%), rather than bound (6%), and consisted of various phenolic acids (such as caffeic acid, chlorogenic acid, gallic acid, and protocatechuic acids) and flavonoids (such as catechin, myricetin, kaempferol, and rutin). A  dose‐dependent antiproliferative activity was found when HepG2 cells were incubated with bran phenolics, particularly with the free fraction, with an EC50 of 17 mg/mL. EC50 value of tartary buckwheat bran was lower than that of lemon, banana, grapefruit, peanuts, and almonds (26–130 mg/mL), but higher than those of pinto beans and adzuki beans (0.4–0.5 mg/mL). The authors thus propose that tartary buckwheat bran may be used to inhibit HepG2 cell growth because of their good EC50 value and low monetary cost. The exact mechanism of action was not conclusively demonstrated, but the phenolic compounds present might be chiefly responsible for the effects, while other phytochemicals may also play a minor role. According to the recent evidence described above, cereals and their by‐products are rich in different phytochemicals, such as dietary fiber and various phenolic compounds. Experiments have been performed to validate their effects against some of the most prevalent diseases in modern society, such as obesity, cardiovascular disease, diabetes, cancer, and others (Figure 1.3). Evidence obtained from various models suggests that they can promote health through various concerted

1.7  ­Current and Future Perspective

actions in the gastrointestinal tract, liver, serum, and other tissues and organs. The mechanism of action is partially known in some cases, but additional experimentation is required to thoroughly comprehend the observed actions, as well as identify which compound(s) is(are) responsible.

1.7  ­Current and Future Perspectives Breeding efforts have resulted in reduced bran/hull content of some cereals, ­particularly oats and wheat. Regular (covered) oat hull represents 25–30% of the kernel weight and therefore harvest yield; in contrast, naked oat hull (4–6% of covered seed) separates easily during the threshing operation [81]. Naked oat cultivars contain 1–6% hull, are higher in yield, protein and fat contents, compared to husked grains, and can substitute rice in many dishes [82–84]. Recently naked oat cultivars such as AC Gehl developed by Agriculture and Agri‐Food Canada (AAFC) are almost free of fine surface‐borne hairs (trichomes) – a major health challenge for harvesting, processing, and handling of the grain. This class of Canadian naked oats has been incorporated into a new line of soup products “Campbell’s Canada Nourish” to fight against hunger (http://www.canadian‐oats. com). Naked oats, unlike traditional oats, can be processed without dehulling and sorting and require less storage space and transportation costs because of high density. White wheat dominates wheat production in Australia and accounts for 10–15% of the US wheat crop [85]. The phenolic compounds expressed by the bran color genes in the traditional hard red wheat are absent in whole white wheat and is preferred in many countries, especially in Asia for noodle production. The  bran of white wheat is therefore lighter in color and milder in flavor than traditional wheat. Whole white wheat (100%) is currently marketed for bakery products that can claim “whole wheat” in their labels to consumers. Fiber is in the market spotlight and it can efficiently be sourced from bran, a major by‐product of the cereal industry. The high ratio of insoluble dietary fiber in cereal brans can be transformed into useful ingredients for multiple food and other applications [86]. For example, “Fibersol,” a digestion‐resistant maltodextrin, can be labeled as soluble corn fiber (prebiotic) with a wide range of food and other applications [87]. However, replacement of dietary fibers from wheat, ­barley, and rye with other fiber sources changes the intestinal microbiome during low‐gluten diet intervention in healthy middle‐aged adults [88]. Bran oil, particularly from rice bran, is underutilized, although it is a common cooking oil in Asian countries where rice bran is inexpensive and readily available. Rice bran containing 20% oil is generally stabilized by thermally inactivating lipase enzyme and the oil extracted mechanically, using solvents or other “green” methods such as supercritical CO2 extraction. The oil is refined (degummed, neutralized, bleached, dewaxed, and deodorized) sometimes using low temperature

25

26

1  Cereal/Grain By-products

to preserve the bioactive compounds γ‐oryzanol and phytosterols; crude rice bran oil contains 15 g per kilogram of γ‐oryzanol. Rice bran oil consumption lowers total and LDL‐cholesterol levels in humans [89]. Wheat bran oil contains higher amount of total phytosterols than rice bran oil (2455 vs. 990 mg/100 g) and is as effective as rice bran oil in reducing plasma cholesterol [90]. The antioxidant and hypolipidemic properties of wheat bran oil have been enhanced using silicic acid coupled with acetone extraction. The extract, rich in fat‐soluble bioactives, ameliorates lipid profile, antioxidant enzymes (SOD, catalase, GPx, and GR), and activities in the liver by downregulating HMG‐CoA reductase expression [91]. Protein concentrates (~58% protein) have been obtained from industrially defatted rice bran with 31 and protein yield, 15 000 Da), heat sensitive (inactivated within 10–15 minutes at 60–100 °C) (e.g. helveticin J).

Class IV

Complex proteins that contain lipid or carbohydrate moieties [95, 96].

Source: adapted from references [28, 30]. Reproduced with permission of SciELO, Taylor & Francis.

2.4 ­Bacteriocin

Many bacteriocins are resilient to heat (Table 2.1), with some compounds withstanding temperatures exceeding 60–100 °C for 30 minutes and some even surviving ­autoclaving at 121 °C for 15–20 minutes [70]. The molecular masses of these compounds can vary by orders of magnitude. For example, bacteriocins produced by LAB can range from small peptides (e.g. lacticin 481, 1700 Da) to protein–protein and protein–lipid aggregates and macromolecules with molecular masses in excess 200 000 Da (e.g. lactocin 27, lactacin B, helveticin J) [70]. Regardless of molecular mass and classification, bacteriocins kill or inhibit bacterial cell growth by disrupting essential functions such as transcription, translation, replication, and cell wall biosynthesis [98]. Unlike traditional antibiotics, which mostly act as enzyme inhibitors [99], the primary target for most bacteriocins is the cell surface or the cytoplasmic membrane resulting in altered membrane permeability [70, 98, 100–103]. Therefore, bacteriocins often form a transmembrane helix or an amphiphilic α‐helix [104, 105]. Changes to the cell surfaces induced by bacteriocins result in detrimental effects to membrane transport and disruption of the proton motive force [70]. This cell membrane disruption can inhibit energy production, protein biosynthesis, or nucleic acid biosynthesis [70]. Furthermore, bacteriocins can induce the formation of membrane channels or pores, resulting in the leakage of cellular solutes, poor growth, viability, and cell death [98, 100–103]. Bacteriocin‐producing organisms protect themselves from their own toxins by expression of specific immunity proteins that are often encoded in the bacteriocin operon [28, 106]. For example, lantibiotics inhibit growth of Gram‐positive bacteria by inducing pore formation in bacterial membranes [107]. These lantibiotic producers can synthesize the immunity lipoproteins LanI or LanH, which protect against the effects of their own bacteriocins. The immunity peptides are located at the membrane, in the extracellular space or as transmembrane proteins [108–110]. These proteins protect bacteria by preventing insertion of these bacteriocins and thus inhibit pore formation [28, 111]. Furthermore, many ­bacteriocins can be inactivated by an array of proteolytic enzymes (e.g. trypsin, pepsin, proteinase K, etc.) [70]. Bacteria can acquire or lose immunity against specific bacteriocins through horizontal gene transfer (e.g. transformation, transduction, conjugation, and gene transfer agents). This could provide a means of transferring antibiotic and antimicrobial resistances between organisms [50]. Large plasmids carrying genes encoding various metabolic traits (e.g. bacteriocin and immunity protein production) may be transferred between lactobacilli to construct new starter strains with desired properties [89, 112, 113]. Horizontal gene transfer has been reported for a variety of lactobacilli, including L. rhamnosus [114], L. gasseri [115], L. paracasei [116], L. reuteri [117–119], and L. plantarum [119]. Therefore, the sharing of genetic material among bacteria can provide a synergistic route to acquire

45

46

2  Enrichment and Utilization of Thin Stillage By-products

­ acteriocin immunity or shared traits (e.g. production of cobalamin or 1,3‐PD b conversion) among coexisting microbes present in TS.

2.5 ­Separation and Purification of Bacteriocins Several bacteriocins cannot be isolated from the producing cells [120]. Furthermore, contrary to historic investigations [121–123], some bacteria (i.e. lactobacilli) excrete bacteriocins to the liquid media in which they are grown (e.g. TS) [124]. This was further corroborated in Tse et al. [33] where a consortium of lactobacilli were successfully cultured and fermented on W‐TS over 170 consecutive batches or 510 days, and next‐generation sequencing revealed various bacteriocin gene sequences present in W‐TS organisms [33]. Purification of bacteriocins, especially those produced by LAB, has proven to be a difficult task. Problems encountered during purification could be related to the tendency of such molecules to associate with other molecular substances, their hydrophobicity, etc. Additionally, because they form such an extremely heterogeneous group of substances, specific purification protocols generally need to be empirically designed for each bacteriocin [70]. Some bacteriocins purified to homogeneity have been reviewed [70, 125]. Current techniques to separate, isolate, and purify lactobacilli and bacteriocins include centrifugation (i.e. to concentrate the peptide present in the culture supernatant) [126], solvent separation and extraction (e.g. acetone, ethanol, chloroform) [124, 127–131], chemical precipitation (e.g. salt precipitation) [132, 133], chromatographic techniques (e.g. reverse‐phase high‐performance liquid chromatography) [133–139], or pH manipulation (i.e. increase pH to adsorb onto producer bacteria and lowering pH to desorb them) [140]. However, LAB are fastidious microorganisms that typically require rich and complex growth media [125]. Problems in purification can arise if the growth media contain interfering peptides within the bacteriocins mass range [141]. Because of the presence of media contaminants, lyophilization or direct removal of water from culture media is not recommended [123]. Instead, modification of culture media to minimize interfering peptides could be implemented [123]. Evaporation or membrane concentration of bacteriocin peptides reduces the working volume without increasing purity. Chromatographic steps are normally employed to achieve higher purity, and a combination of isolation techniques are normally required for concentration and purification [125, 142]. Such methods can be expensive and afford low yields [70, 125]. Interestingly, a novel method proposed bacterial growth on low molecular weight medium containing nutrient sources (100 °C for lectin reduction), autoclaving, cooking, or extruding removes most antinutrients due to their heat‐sensitive characteristic. Additionally, germination, ensiling, and treatment with pancreatin or chemicals have been successful in reducing these antinutrients [1], improving other properties such as their digestibility. The in vitro and in vivo digestibilities have been reported for legume (navy bean and cowpea) residues, a waste by‐product [9]. After phytohemagglutinin inactivation and 48 hour‐air drying treatment (45 °C), the diets (30, 70, and 100% for both navy bean and cowpea residue concentrations) were administered to male weanling Sprague‐Dawley rats for four weeks. The protein in vitro digestibility results showed that digestibility increased with increasing residue concentration, whereas the 100% navy bean residue diet reduced rat weight probably as a result of limiting amino acid profile. The other diets showed a slow pattern supporting rat weight, improving food intake, and growth of the rats. Beans are difficult to mill industrially due to the drying conditions that affect seed quality. In this manner, an important amount of “broken” is generated during beans milling (for example, “broken” represented an estimated 0.025% of the total beans production in 2012 in Brazil) that could be useful for making a high protein (20%), carbohydrates (64%), and dietary fiber (7%) flour at a low cost (1/5 of the whole bean flour cost) [10, 11]. This flour has been evaluated in extruded snacks, cereal‐type meals (flakes), and cookies from broken rice and broken common beans improving their nutritional quality and consumer acceptance (~80%) [12, 13]. Dehulling could be an alternative in developing countries for taking advantage of hard‐to‐cook beans and those already affected by storage and drying conditions [14]. Since the dehulling process generates a mixture of seed coats, embryonic axes, and broken cotyledons or seeds (splits), dehulling loss is the main waste stream of pulse processing. Depending on the processing conditions and the time of processing, dry beans hull yield can vary from 4.0–67 g/kg of beans at 30 seconds of dehulling time to 20–152 g/kg at 120 seconds of dehulling time, using an abrasive dehuller and a previous microwave treatment of black (AC Black Violet and AC Black Diamond) and pinto (AC Island) market class beans cultivars [15].

63

64

3  Pulse By-products

This indicates that several rates of by‐products could be obtained considering the technological available resources, generating an important amount of waste that is mainly used for animal consumption or as a very limited ingredient to manufacture high‐fiber food products such as breads and meat products [6]. Therefore, these by‐products offer an enormous potential for their content of bioactive ­compounds. This property can essentially be exploited for polyphenol content, particularly in colored bean varieties. The hulls, despite representing a small portion of the seed (7–13%), are rich in dietary fiber, minerals, and polyphenols with strong antioxidant activity, making them appropriate for developing food products [16]. High antioxidant capacity of methanolic extracts has been reported from hulls manually obtained from red common beans, cv. Flor de Mayo FM‐38 (ARA: 30.7 and TEAC: 2.4) [17]. The anti‐inflammatory and the antioxidant activities of common bean hulls vary widely in polyphenols depending on cultivar, where the most colored varieties showed the highest concentration of total phenolics and anthocyanins and the highest oxygen radical absorbance capacity (ORAC) antioxidant activity (282–342 mg/g Trolox) [15, 16]. Black bean hulls displayed the highest anti‐inflammatory activity (COX‐1 and COX‐2). However, not the black, but another colored variety (pinto beans, named “Othello”) showed the lowest IC50 for lysyl oxidase (LOX) inhibition. Specific components of common bean seed coats have demonstrated interesting health effects. Flavonoids and saponins from seed coats attenuate lipogenesis and stimulate fatty acid oxidation and cholesterol biliary excretion through a differential regulation of liver X receptor (LXR) by activated protein kinase (AMPK) phosphorylation [18]. Quercetin‐3‐glucoside is the primary flavonoid of black bean (P.  vulgaris L.) extracts, whereas soyasaponin Af is the most abundant saponin [19]. This extract, rich in these two compounds, reduced both SREBP1c and FAS expression in primary rat hepatocytes, and enhanced the transporter ABCG5 expression, similar to the synthetic ligand of LXR. This transporter, synthesized in the endoplasmic reticulum, is a reverse cholesterol transporter that limits the intestinal cholesterol absorption and promotes the biliary sterol excretion. In a five‐week in vivo study using C57BL/6J mice (21 days old, initial body weight: 12–15 g) fed with cholesterol and diets containing these flavonoids and saponin‐ rich extracts did not significantly modify body weight gain but reduced total and HDL‐cholesterol levels in mice serum. Lipogenic proteins were suppressed at both the mRNA and protein levels in the livers of mice subjected to this treatment. Incorporation of these saponins did not affect the organoleptic and functional properties of whole wheat breads, except the crumb color due to the origin of saponins derived from black bean [20]. The thermal and enzymatic resistance of flavonoids and chemical compounds attached to saponins enabled high retention of these components after baking (88–91% of added flavonoids and 80% of ­anthocyanins, respectively); however, their retention after in vitro enzyme

3.2 ­Beans By-product

­ igestion was low ( chilies and peppers, green > cauliflow­ ers and broccoli > pumpkins, squash, and gourds. China, México, Netherlands, Spain, and Canada have remained the main exporters of fresh vegetable products, except Canada, which ousted the United States. The main importers of registered fresh vegetables are United States,

Millions

8.2  ­Global and/or by Region Vegetable Food Production and Postharvest 200 Chilies and peppers, dry

180

Cauliflowers and broccoli

160

Vegetable production (ton)

Wast

140

Cucumbers and gherkins

120

Chilies and peppers, green

100

Pumpkins, squash, and gourds

80 Tomatoes

60

Cabbages and other brassicas

40 20 0

China

Egypt

India

Indonesia Iran

México Russian Spain Federation

Turkey

United states

Figure 8.4  Top 10 countries with the highest world production of vegetables that produce agro-industrial waste. Source: FAOSTAT data food balance sheets for crop production quantity in 2016 [3].

Western Europe, Japan, and gradually India, China, the United Arab Emirates, and Russia are increasing their imports [5].

8.2.1 Tomato Solanum lycopersicum is the second most consumed vegetable around the world, and it has attractive nutritional and nutraceutical characteristics such as vitamins, organic acids, carotenoids mainly lycopene, and phenolic compounds (ferulic and caffeic acids, naringenin, and others) [6, 7]. Tomato is fresh or processed and regu­ lar consumption has been associated with reduced incidence of diet‐related chronical diseases, such as cardiovascular diseases and some cancers [8, 9]. Throughout the tomato supply chains, large losses and wastes of this vegetable are mainly due to consumer behavior and inefficiencies in the production systems [10]. Also, tomato industrialization generates large quantities of by‐products around the world, which are mostly not valorized, despite several investigations demonstrating different uses. In 2016 global tomato production was over 177 Mt, with an average yield of 41 t/ ha, and its production increased around the world; China is the main producer with approximately 30% of the world’s production, followed by India, United States of America, Turkey, and Egypt with México ranked as 10th [11, 12].

227

228

8  Vegetable By-products

In general, postharvest losses are either an on‐farm or off‐farm problem. On‐farm losses are caused by improper harvesting stages, perishable nature of the product, improper harvesting containers, poor farm sanitation or pest‐­contaminated product, and packaging materials. In 2017, the World Processing Tomato Council reported important field and postharvest losses due to different climate factors such as heat, storms, etc. [13]. Approximately 70% of fresh tomatoes are distributed through the traditional marketing system, transferred to shipping point markets in the vicinity of the producing area, and the other 30% are delivered to consumers through a modern marketing system, wherein the fruits are properly packed, cooled, and handled [13]. In China, the postharvest tomato losses are up to 35% [14], representing more than 15 Mt. Fresh tomatoes are produced in all Chinese provinces, but four prov­ inces (Shandong, Xinjiang, Hebei, and Henan) are the major producers. Tomato processing and industrialization is carried out in other provinces, and its mobili­ zation is one of the causes of the big postharvest losses [15]. Other countries of the Asian continent such as Bangladesh, India, Cambodia, and Turkey reported tomato postharvest losses up to 23, 40, 25, and 20%, respectively [14, 16, 17]. In Bangladesh, postharvest tomato losses were estimated along the supply chain from 2016 to 2017. The results showed that the losses at farmer, trader, wholesaler, retailer, processor, and consumer levels were 9.3, 1.7, 2.0, 4.0, 5.4, and 2.4% of the total after harvest losses of tomatoes, respectively [18]. In Australia, tomato postharvest loss was between 40.3 and 55.9% of the total harvestable product. Also, up to 86.7% of undamaged, edible, harvested tomatoes were rejected as outgrades and consequently discarded due to product specifica­ tions, increasing the postharvest losses [10]. Different countries of northern Africa have made tomato as an important prod­ uct in their diet. In Africa, the total tomato production for 2012 was 17.94 Mt, with Egypt leading with 8.6 Mt, which represents more than 50% of the production. Nigeria and Tunisia are also important tomato producers [12]. Tomato posthar­ vest losses reported in different African countries ranged between 20 and 30%, specifically in Egypt, Benin, Ghana, Nigeria, and Rwanda, where the losses are 15, 28, 25, 20, and 30%; wastes are mostly produced in farms and transportation, due to inadequate infrastructure for their mobilization [14]. That is the reason why in countries such as Nigeria the majority of production is locally consumed. Great tomato losses are reported in the United States. Florida generates almost 50% of the total production in the country, producing over 390 kt of wastes every year. In this state, driven by the urbanization and generation of large amounts of tomato culls, tomato packers are trying to find ways to dispose culls after cleaning and sanitizing of tomatoes, and driven by the high transportation costs to off‐site disposal, the farmers are searching for local transformation of tomato value‐added products [19]. In Peru and Brazil, postharvest losses are 13 and 10%, respectively [20, 21]. México, the 10th tomato producer in the world, produced 3 Mt in 2015,

8.2  ­Global and/or by Region Vegetable Food Production and Postharvest

Wast

but the postharvest losses – mainly due to climate and market conditions – can reach up to 20% of the open field production [22]. Greenhouse and shade mesh production generate postharvest losses of up to 18%, mainly in the production for the national market, due to an inadequate man­ agement of the cold chain [23]. In most countries with emerging economy, the efforts to provide value to tomato wastes from postharvest losses are null.

8.2.2  Chili Chili belongs to the Capsicum genus. It is the seventh more produced commodity in the world, regardless of its pungency degree, which may be not pungent ( Ethiopia > China  > Côte d’Ivoire > Pakistan > Bangladesh > Myanmar > Ghana > Vietnam) accounts for up to 80% of world production. China is the main producer of green chili, provid­ ing 50% of the annual world production (17.44 Mt) and together with the 10 main producers (México > Turkey > Indonesia > Spain > United States > Nigeria > Egypt >  Algeria > Tunisia) constitutes 84% of world production [11]. The consumption of green chili is preferably fresh; external appearance and color are crucial characteristics that define the quality and consumer acceptance. Special postharvest care is required to maintain the quality and life of the product because they undergo rapid deterioration. Temperature is one of the key factors to extend the shelf life, up to two to three weeks under the conditions of adequate cooling. Postharvest losses in this crop is estimated to range from 5 to 25% in developed countries and from 20 to 50% in developing countries [24]. The interest in this crop not only lies in its versatility in size, shape, color, flavor, and pungency in the culinary field but also in its nutritional composition, as an important source of vitamins and antioxidants and phytochemicals such as ­capsaicinoids that can be used in the cosmetic and pharmacological industries.

8.2.3  Broccoli and Cauliflower Broccoli and cauliflower belong to cruciferous vegetables that have been widely accepted as a good source of potent bioactive compounds released after digestion

229

230

8  Vegetable By-products

that protect DNA from damage, which may reduce the risk of cancer [25–27]. FAO consolidated data on the production of brassica, broccoli, and cauliflower. In 2016, the global production was estimated about 35.5 Mt, with China, India, United States, Spain, and México as the main producers (10.2, 8.2, 1.3, 0.6, and 0.6 Mt, respectively) [11]. Both products, broccoli and cauliflower, are reported as vegetables with a lot of wastes or by‐products, which are therefore being considered to be developed as functional food ingredients.

8.2.4  Zucchini Cucurbita pepo is an important crop with ethnobotanical, phytochemical, ­pharmacological, and nutritional values. The fruit, flowers, young leaves, young shoot tips, seeds, and immature and mature fruits of C. pepo are edible. Immature fruit can be found in many shapes, from spherical to elongated, and they vary in skin color from dark to light green, sometimes with fine white mottling or stripes [28]. It is low in calories and commonly used as a vegetable around the world; its nutritional components, like carbohydrates, proteins, lipids, vitamins, and miner­ als, are well known. Additionally, this plant has ethnomedicinal uses in Africa and Asia for its effectiveness in the treatment of fever, whopping cough, urinary problems, scurvy, hyperplasia, rheumatism, hemorrhoid, miscarriage, prostate cancer, constipation and blindness. Other ethnomedicinal uses of C. pepo are as antibacterial, antioxidant, antitumor, hypoglycemic (antidiabetic), and hypolipi­ demic. These medicinal activities could be due to the presence of diverse phyto­ chemical compounds including flavonoids, terpenoids, cardiac glycosides, and cucurbitacin glycosides. Therefore, more research should be done on the ­phytochemicals present, as well as their biological activity, since most of the data reported relate to the composition of mature fruits (pumpkin) and seeds [29, 30].

8.2.5 Cucumber Cucumis sativus L. belongs to the Cucurbitaceae family. It is a vegetable crop native of India but commercially cultivated around the world [31]. It is commonly consumed fresh in salads, fermented (pickles), or cooked as a vegetable  [32]. Although it has been used in traditional medicine from ancient times, particularly in the Indian Ayurveda, some studies have been developed to investigate its chem­ ical profile and therapeutic potential. Some of the medicinal uses of cucumber are skin refresher, emollient, itching reliever, anti‐wrinkle for its antioxidant content, antimicrobial, antidiabetic, treatment of ulcers and colitis, hypolipidemic, and wound healing, among others [33, 34]. Cucumber’s peel and plant are commonly considered waste, and therefore there have been few chemical studies regarding

8.3  ­Global and/or Regional Vegetable Industrialization and By-Product Generatio

the phytochemical constituents of these materials with interesting findings about the variety of bioactive components.

8.3 ­Global and/or Regional Vegetable Industrialization and By-Product Generation Only 7% of the total vegetable production is transformed into preserves, frozen products, concentrates, juices, and nectars, which gives rise to an important amount of organic by‐products (15–65%). At any food production chain, there are vegetable losses; however, up to 38% of these occur during food processing. Vegetable by‐products are all plant residues that are derived from the raw material of processed vegetables, obtained from cutting, slicing, peeling, etc. These by‐ products consist of peel, seeds, bracts, stems, leaves, roots, bark, petioles, midribs, pieces, heart, etc. They contain various compounds of nutritional and functional interest (vitamins, pigments, antioxidants, phytochemicals), which can be recov­ ered and used as ingredients in the food, chemical, pharmaceutical, agricultural, and cosmetics industries. Furthermore, if the by‐products are properly managed, they can generate economic and environmental benefits. Since 2014, around 40–50% of global food loss and waste correspond to root crops, fruits, and vegetables, which depend on specific conditions and culture in different countries [35]. The vegetable wastes include seeds, stems, peelings, trim­ mings, shells, brans, and residues remaining after starch, sugar, juice, and oil.

8.3.1 Tomato Producers, wholesalers, retailers, and consumers are concerned about maintain­ ing quality and reducing marketing losses. Factors relating to causes, types, and magnitude of damage that lead to quality deterioration and postharvest losses have been significant for the growth and development of the tomato industry. About 30% of the total tomatoes consumed by humans is in the form of industrial­ ized tomato‐derived products, such as tomato paste, ketchup, juices, sauces, etc. During their industrialization, considerable quantities of wastes or by‐products are generated; to date, their biotechnological potential has not been exploited. There are few reports about the quantities of industrial by‐products generated in different countries or regions around the world. China has a large tomato industry, with currently around 166 tomato sauce processing factories established in the country, thereby accumulating great quantities of industrial by‐products [35]. In the last decade, Turkey processed 2 Mt of tomatoes per year, approximately (15–20% of the total production) [17]. In Africa, generally, the inefficiencies in postharvest handling of tomatoes have created a demand in processed products

231

232

8  Vegetable By-products

that are imported, losing the opportunity to implement a local transformation industry. In México, 1–2% of the total annual production of tomato is industrial­ ized [13]; however, there is no reported amount of tomato by‐products. In Northern México (Sinaloa State), a vegetable processing industry is established, which processes about 50 kt of tomatoes annually, generating on average more than 3 kt of tomato by‐products, consisting of 60% peel and 40% seeds once dried (Figure 8.5). The by‐product is not valorized but used only for generating compost or disposed in the environment.

8.3.2  Chili México is considered the second world producer of green chili, after China. Green chili production reached 2.42 Mt in 2016, corresponding to 21.3% of the vegetables

(a)

(b)

(c)

Figure 8.5  Industrial tomato by-product. (a) Industrial tomato by-product in the open box of a truck, ready for disposal as an ingredient for compost. (b) Close view of industrial tomato by-product, composed of 60% peel and 40% seeds (dry basis). (c) Industrial tomato by-product dried in a forced-air convection oven.

8.3  ­Global and/or Regional Vegetable Industrialization and By-Product Generatio

grown in México. As the primary exporter about 40% of México’s production is exported as fresh, dried, and prepared chili, contributing 28.7% to the world exports that reach 3.3 Mt among the 138 exporting countries [22]. After harvest, chili can be marketed fresh or be processed canned, pickled, sliced or diced frozen, fermented, dehydrated, or transformed into products as puree, paste and sauce, flavoring or coloring powder, or extracted for oleoresin. Canning is one of the main process used for jalapeño and pimiento Mexican chili. They can be previously peeled by flame roasting, with steam, or using lye. Further acidification of the product (pH  0.1 mg/mL and 0.2 mg/mL, respectively), while “Light Green” zucchini skin induced internucleo­ somal DNA fragmentation, probably due to the presence of β‐carotene. The results showed the potential of zucchini to improve consumer’s health, as well as the implicit anticancer activity, which requires detailed study. 8.5.4.3  Leaves and Stems

The cytotoxicity of hydroalcoholic extracts of C. pepo leaves and stems was stud­ ied on normal (Chinese hamster ovarian cells [CHO] and rat fibroblast) and cancer (HepG2 and CT26) cell lines by colonogenic assay method [111]. Cucurbita pepo extract presented high IC50 values on all four cell lines compared to the control cisplatin, which implies a relatively low cytotoxic effect. Nevertheless, higher cytotoxic effect was observed on cancer cells compared to normal cells. The authors suggest that the plant can be a promising source of potential anticancer agents to treat or control various cancers such as liver and colon cancers. Since NF‐κB controls cellular growth and regulation, it is necessary for the can­ cer treatment, but few studies focus on the interactions between the phytochemi­ cals and NF‐κB. The phytochemicals in ethanolic extract of C. pepo leaves were investigated by gas chromatography–mass spectroscopy technique, and in silico approach was used to understand the interaction between the identified phyto­ chemicals and NF‐κB using Molegro Virtual Docker [74]. According to the results, nine of 14 identified phytochemicals fit well into the pocket on NF‐κB, and Lys144 is the main residue involved in binding 9‐octadecenoic acid (Z)‐, methyl ester, hexadecanoic acid, methyl ester, and octadecanoic acid. The authors conclude that the binding of these phytochemicals to NF‐κB could be responsible for the anti‐inflammatory and anti‐cancer properties of C. pepo.

8.5.5 Cucumber There is current interest in the study of the biological properties of C. sativus derived from the existing information on its ethnomedicinal uses. Many studies focus on the composition and bioactivities of different parts of the plant, in addi­ tion to the fruit. These studies focus mainly on antioxidant activity, benefits to

247

248

8  Vegetable By-products

dermal health, blood lipid lowering, and beneficial effects in digestive system con­ ditions (ulcers and colitis). 8.5.5.1 Fruit

Most publications about cucumber nutraceuticals and bioactivity focus on the whole fruit. Cucumber in traditional medicine stands out for its properties in skin care and the relief of various skin conditions, and there are several studies related to this biological activity. For example, the antioxidant, anti‐hyaluronidase, and anti‐elastase activity were evaluated for the lyophilized juice of C. sativus fruit [79]. The lyophilized juice presented 3.5 ± 0.23% w/w of ascorbic acid, exhibited DPPH‐free radical and superoxide radical scavenging activity (IC50 at 14.73 ± 1.42 and 35.29 ± 1.30 μg/mL, respectively), and significantly inhibited the hyaluroni­ dase and elastase activities (IC50 at 20.98 ± 1.78 and 6.14 ± 1.74 μg/mL, ­respectively). The authors concluded that C. sativus may have potential as anti‐ wrinkle agent in cosmetic products and suggested that other effects on skin care be explored further with its enzyme inhibition activity. On the other hand, a cream formulation was developed containing different concentrations of aqueous extract from C. sativus L. fruit [113]. The rate of wound contraction and epitheli­ zation was tested in excision wounds (300 mm2 and 2 mm depth) in laboratory animals treated with formulated creams. The cream formulations did not show any sign and symptoms of skin irritation when applied topically. The authors observed significant decrease in wound area, epithelization period, and scar width, whereas the rate of wound contraction increased significantly (P 200 mg/L) than other mixtures and with the net solvent. Chili agri‐food industry waste dye can be a promising antimicro­ bial agent and a sustainable alternative to substitute synthetic dyes for developing bioactive textile materials and clothing [120].

8.7  ­Commercialization or Transformation in Value-Added Products

8.7 ­Commercialization or Transformation in  Value-Added Products 8.7.1 Tomato Tomato by‐products are highly perishable due to high moisture (>80%) content and thus must be preserved by drying or other methods to obtain natural extracts or used directly as an ingredient. For this purpose, several methods have been improved to extract carotenoids, phenolics, proteins, and lignocellulosic bio­ mass – at the laboratory or pilot plant scale [121–123]. A kinetic modeling of lyco­ pene extraction with solvents from tomato by‐product was performed, demonstrating that the temperature and nature of the solvent process variables strong affect extraction [121]. Carotenoids (particularly lycopene) yield increased by an enzymatic extraction using pectinases [123]. Lycopene extraction from tomato by‐products have also been improved by a microwave‐assisted extraction system, increasing the levels of total sugars, reducing sugars, proteins, and total phenols [124, 125]. Efforts mentioned earlier are aimed to develop, in the near future, products with added value that can reach the final consumer. In this way the following research works have been reported. Ethanolic extracts of tomato by‐product were incorporated in canola oil to replace synthetic antioxidants, used in commercial vegetable oils as oxidative sta­ bilizers [126]. Tomato by‐product flour supplementation did not affect the phys­ icochemical characteristics, texture, and cooking quality of an extruded corn snack [127]. Low concentrations of lipophilic extracts of tomato by‐products inhibited the formation of peroxides, conjugated dienes, and unsaturated fatty acid oxidation of butter [67]. The tomato by‐product has great potential to be used as an antioxidant to extend the shelf life of this type of products. Bakery products supplemented with tomato by‐products flour have improved nutritional proper­ ties, such as dietary fiber, vitamin C, and minerals, and also antioxidant activity [128]. In addition, the incorporation of tomato waste led to obtaining a product with acceptable sensory properties and improved shelf life. Tomato seeds have been used as a source of oil for nutritive or industrial purposes, the content of linoleic acid was attractive (up to 39.9 mg/mL), but the extraction yield must be improved [129]. Based on our knowledge there are no commercial food products on the market manufactured using tomato by‐products, but taking into account its nutraceutical potential, and the large quantities in which it is generated around the world, more efforts should be made to valorize this material. On the other hand, currently one way to valorize agro‐industrial vegetable by‐ products, including tomato by‐products, is through the innovative concept of

253

254

8  Vegetable By-products

biorefinery, which is defined as an approach for the generation of value‐added products such as biochemicals and biofuels, among others, from biomass. A cas­ cade biorefinery process has been proposed to add value to industrial tomato by‐ products through the recovery of compounds of interest [122]. The process integrates the carotenoid extraction by supercritical CO2, followed by protein iso­ lation from the residues and hydrolysis of lignocellulosic matter. Thus, tomato by‐products are not only a natural source of lycopene, oil, and protein but also a good source of lignocellulosic biomass to produce bioethanol. Extraction of lycopene from tomato by‐products have been proposed in diverse patent applications. Cristal lycopene was obtained from tomato paste generated after juice extraction, the paste was washed with alkali liquor, and lycopene was extracted with organic solvent, flash evaporated for concentration, and further cooling to crystalize lycopene; crystals contain more than 10% of this carotenoid [130]. In other patents, lycopene was obtained from tomato wastes, by distillation processes, with a purity of between 65 and 85%; and using active carbon to remove impurities and extracting by solvents [131, 132]; also, tomato pomace have been proposed as a source of cutin‐derived monomers, oligomers, or combinations; the extractions was conducted using soxhlet systems and different solvents, such as heptane, ethyl acetate, and ethanol [133].

8.7.2  Seed Chili Red pepper seed oil has been extracted from compressed oil through steam distil­ lation with specific parameters to obtain the vivid red color and the spicy compo­ nents from the oil. The procedure removes the odorous components, eliminating the uncomfortable flavor and unpleasant taste from red pepper seed oil, offering a versatile application for cooking food or developing of new food products. Furthermore, this includes a formulated pepper seed oil with flavoring ingredi­ ents, which could be used in mayonnaise and dressings or as raw material as noo­ dles and bakery foods [134]. Capsaicin (99.8%) is the main product obtained from red pepper seeds and skin generated from industrial production of Capsicum, to develop capsaicin oil, chili powder, chili sauce base material, or red pigments. Capsaicin is produced from dry cleaned whole pepper that is milled, extracted with alcohol, ether or alkanes, concentrated and crystallized to high purity for medical, food, paint, and other uses [135]. Pepper seasoning seed comprises pepper seeds and skin and is uniformly mixed with other fried components to provide pepper flavoring with different tastes and without seed [136]. Obtained from the pepper seed, pepper seed oil contains above 30% of the alpha‐linolenic acid and has intense spicy smell. The procedure involves crushed

8.7  ­Commercialization or Transformation in Value-Added Products

pepper seeds and frying seeds that are expelled and dewaxed. Other processes include extracting low‐polarity organic solvent and processing extraction liquid on the upper and lower layers, where in the upper layer is recycled by recovering organic solvent. Then alkaline refining is performed and the yield of the product is improved [137]. Pepper seed oil has been extracted by a simple procedure with pretreated water enzymatic method and further assisted with ethanol as a green‐safe and hygienic technology. The method comprises six steps: (i) seed powder (removing impuri­ ties, drying, crushing, and sieving the pepper seeds); (ii) mixture (mixing seed powder and water); (iii) zymolite obtention (adding a food‐grade enzyme and per­ forming the enzymolysis and further inactivation); (iv) drying the zymolite; (v) oil extraction with methanol; and (vi) recovering oil by evaporating the solvent [138].

8.7.3  Broccoli and Cauliflower Cauliflower by‐product flours (florets, curd, stem, and leaves) were used to replace wheat flour for the elaboration of extrusion products [139]. Addition of cauli­ flower significantly affected expansion index, bulk density, color, and total cell area in bread. The authors reported that both total phenolics and total antioxidant capacity were not affected by cauliflower incorporation. Only dietary fiber was improving (up to 100%). Sensory analysis showed that cauliflower by‐products could be added up to 10%. The authors concluded that cauliflower by‐products could be used as a source of dietary fiber in cereal based ready‐to‐eat expanded snacks. Broccoli floret and broccoli stalk freeze‐dried powders were used to develop a ready‐soup rich in bioactive isothiocyanates and in sulforaphane [140]. Broccoli stalk‐enriched soups have significantly higher sulforaphane and total isothiocy­ anate levels compared with control soups. Microwave treatments (at three differ­ ent power levels) did not result in differences in sulforaphane production; this has practical implication from a consumer perspective, where different cooking con­ ditions for ready‐soup will generate bioactive compounds. Broccoli leaves powder [141] was used to improve the content of biological active compounds and the antioxidant capacity of gluten‐free cakes. The authors claim glucosinolate content increases proportionally to broccoli leaves powder content, as well as antioxidant capacity. Sensory evaluation results of cakes elabo­ rated with 2.5% w/w of broccoli leaves powder were described as palatable and soft and characterized by an intriguing vivid green color. Flours obtained from broccoli stems and leaves were used to enrich a spreadable cheese [142]. The inclusion of 5% of by‐product into cheese formulation increases total phenolic content (TPC), total flavonoids content (TFC), and antioxidant activity measured by ABTS and FRAP assays compared to control. The authors concluded that

255

256

8  Vegetable By-products

i­ nclusion of vegetable flour must still evaluate technological options to improve cheese properties to increase antioxidant compounds without compromising the sensory properties. The production of glucoraphanin from cruciferous by‐products and waste to be incorporated into a variety of food products, pharmaceuticals, health supple­ ments, and related products was described in a patent [143]. In this process, glu­ cosinolates are absorbed onto an anion exchange membrane, following extraction and dialyzing step. The patent authors describe glucosinolate extractions from broccoli florets.

8.7.4  Zucchini Waste raw materials peels and seeding of C. pepo and courgette has been provide an enzymatic formulation to be applied in the nutrition field of C. pepo crop, pro­ viding protection of the plant since the planting and increasing their yield, through to a rapidly healthy grow, preventing diseases and insect pests, and improving the soil environment. Raw materials are mixed with brown sugar, min­ erals, and microorganism (yeast, B. subtilis, A. niger, and Monascus purpureus) creating a formulation environmentally friendly [144].

­Acknowledgments The authors are grateful to Instituto Politécnico Nacional SIP 20172264, SIP20181714, SIP20182332 and SIP20181449, for the funding granted to develop research projects with tomato and jalapeño pepper by‐products, which have been compiled in this document.

­References 1 WHO (2013). Global Strategy on Diet, Physical Activity and Health. http://www. who.int/dietphysicalactivity/fruit/en (accessed 11 November 2018). 2 Global Dietary Database (2018). Global Dietary Database, Dietary intake of foods and nutrients by country. https://www.globaldietarydatabase.org. 3 FAOSTAT (2018). Production and Food Balance Sheets 2013. http://www.fao.org/ faostat/en/#data/QC (accessed 11 November 2018). 4 Gustavsson, J., Cederberg, C., Ulf, S. et al. (2011). Global food losses and food waste‐Exent, causes and prevention. Rome: Food and Agriculture Organization of the United Nations. 5 van Rijswick, C. (2018). World Vegetable Map 2018, more than just a local affair. RaboResearch Food & Agribusiness 4 https://research.rabobank.com/far/en/ sectors/regional‐food‐agri/world_vegetable_map_2018.html.

 ­Reference

6 Valdez‐Morales, M., Espinosa‐Alonso, L.G., Espinoza‐Torres, L. et al. (2014). Phenolic content and antioxidant and antimutagenic activities in tomato peel, seeds, and byproducts. Journal of Agricultural and Food Chemistry 62 (23): 5281–5289. 7 Bénard, C., Bernillon, S., Biais, B. et al. (2015). Metabolomic profiling in tomato reveals diel compositional changes in fruit affected by source – sink relationships. Journal of Experimental Botany 66 (11): 3391–3404. 8 Li, Y.‐F., Chang, Y.‐Y., Huang, H.‐C. et al. (2015). Tomato juice supplementation in young women reduces inflammatory adipokine levels independently of body fat reduction. Nutrition 31 (5): 691–696. 9 Paur, I., Lilleby, W., Bøhn, S.K. et al. (2017). Tomato‐based randomized controlled trial in prostate cancer patients: effect on PSA. Clinical Nutrition 36 (3): 672–679. 10 Mckenzie, T.J., Singh‐peterson, L., and Underhill, S.J.R. (2017). Quantifying postharvest loss and the implication of market‐based decisions : a case study of two commercial domestic tomato supply chains in Queensland, Austraia. Horticulturae 3 (44): 21–25. 11 FAOSTAT (2018). Food Balance Sheets. Food and Agriculture Organization of the United Nations. http://www.fao.org/faostat/en/#data/FBS. 12 Kojo, I., Ernest, A., Kumah, K. et al. (2015). An overview of post‐harvest losses in tomato production in Africa: causes and possible prevention strategies. Journal of Biology, Agriculture and Healthcare 5 (16): 78–89. 13 WPTC‐World Processing Tomato Council (2017). WPTC World production estimate of tomatoes for processing (in 100 metric tonnes). https://www.wptc.to/ releases‐wptc.php. 14 Kitinoja, L., and Kader, A.A. (2015). Measuring postharvest losses of fresh fruits and vegetables in developing countries. PEF White Paper 15‐02. http:// postharvest.org/PEF_White_Paper_15‐02_PHFVmeasurement.pdf. 15 Beckman, C. and Lei, Z. (2009). Tomatoes and Products, China – Peoples Republic of, Annual Report. 16 Genova, C. II, Winberger, K., Sokhom, S. et al. (2006). Postharvest loss in the supply chain for vegetables – the case of tomato, yardlong bean, cucumber and Chinese kale in Cambodia. AVRDC Working Paper 16: 47. 17 Tatlidil, F.F., Dellal, İ., and Bayramoğlu, Z. (2013). Food Losses and Waste in Turkey. Country Report. Food Losses and Waste in Europe and Central Asia. http://www.fao.org/3/a‐au824e.pdf. 18 Sarma, P.K. (2018). Postharvest losses of tomato: a value chain context of. International Journal of Agricultural Education and Extension 4 (1): 85–92. 19 Toor, G., Chahal, M., and Santos, B. (2015). Solutions for Managing Tomato Culls in Florida Tomato. SL371. 20 Vargas‐Florez, J. and Universidad, P. (2014). Wastes in the supply chain of agro‐industrial products in the valley of Lima. Peru. 4 (2): 67–72. 21 Henz, G.P. (2017). Cover article postharvest losses of perishables in Brazil: what do we know so far? Horticultura Brasileira 35 (1): 6–13. http://dx.doi.org/10.1590/ s0102‐053620170102.

257

258

8  Vegetable By-products

2 2 SIAP (2018). Atlas Agroalimentario 2018. https://nube.siap.gob.mx/gobmx_ publicaciones_siap/pag/2018/Atlas‐Agroalimentario‐2018. 23 Bordon, C. (2017). Análisis de la cadena jitomate o tomate rojo. Reducir pérdidas de alimentos en México. 24 Kader, A.A. (2007). Biología y tecnología postcosecha: un panorama. In: Tecnología Postcosecha de Cultivos Hortofrutícolas (ed. A.A. Kader). Oakland, California: University of California, Division of Agriculture and Natural Resources. 25 Rescigno, T., Tecce, M.F., and Capasso, A. (2018). Protective and restorative effects of nutrients and phytochemicals. The Open Biochemistry Journal 12 (1): 46–64. 26 Moreno, D.A., Carvajal, M., López‐Berenguer, C., and García‐Viguera, C. (2006). Chemical and biological characterisation of nutraceutical compounds of broccoli. Journal of Pharmaceutical and Biomedical Analysis 41 (5): 1508–1522. 27 Lund, E. (2003). Non‐nutritive bioactive constituents of plants: dietary sources and health benefits of glucosinolates. International Journal for Vitamin and Nutrition Research 73 (2): 135–143. 28 Iswaldi, I., Gómez‐Caravaca, A.M., Lozano‐Sánchez et al. (2013). Profiling of phenolic and other polar compounds in zucchini (Cucurbita pepo L.) by reverse‐ phase high‐performance liquid chromatography coupled to quadrupole time‐of‐ flight mass spectrometry. Food Research International 50 (1): 77–84. 29 Adnan, M., Gul, S., Batool, S. et al. (2017). A review on the ethnobotany, phytochemistry, pharmacology and nutritional composition of Cucurbita pepo L. The Journal of Phytopharmacology 6 (2): 133–139. 30 Lim, T.K. (2012). Cucurbita pepo, in Edible Medicinal and Non‐Medicinal Plants: Volume 2, Fruits, 281–294. Dordrecht: Springer Netherlands. 31 Kirkbride, J.H. (1993). Biosystematic Monograph of the Genus Cucumis (Cucurbitaceae). Boone, North Carolina: Parkway Publishers. 32 Sotiroudis, G., Melliou, E., Sotiroudis, T.G., and Chinou, I. (2010). Chemical analysis, antioxidant and antimicrobial activity of three Greek cucumber (Cucumis sativus) cultivars. Journal of Food Biochemistry 34 (Suppl. 1): 61–78. 33 Mukherjee, P.K., Maity, N., Nema, N.K., and Sarkar, B.K. (2011). Bioactive compounds from natural resources against skin aging. Phytomedicine 19 (1): 64–73. 34 Mukherjee, P.K., Nema, N.K., Maity, N., and Sarkar, B.K. (2013). Phytochemical and therapeutic potential of cucumber. Fitoterapia 84: 227–236. 35 Reportlinker (2013). China Tomato Product Industry Report, 2012–2015. https:// www.prnewswire.com/news‐releases/china‐tomato‐product‐industry‐ report‐2012‐2015‐221685971.html. 36 Bosland, P.W. and Votava, E.J. (2012). Peppers: Vegetable and Spice Capsicums. Oxfordshire: CABI Publishing. 37 SIAP (2018). Atlas Agroalimentario 2012–2018, Servicio de Información Agroalimentaria y Pesquera, México City.

 ­Reference

3 8 Alvarez‐Parrilla, E., De La Rosa, L.A., Amarowicz, R., and Shahidi, F. (2011). Antioxidant activity of fresh and processed Jalapeño and Serrano peppers. Journal of Agricultural and Food Chemistry 59 (1): 163–173. 39 Sandoval‐Castro, C.J., Valdez‐Morales, M., Perea‐Domínguez, X.P. et al. (2014). Antioxidant activity of processed and raw seed byproduct from Jalapeño pepper. Journal of Chemical, Biological and Physical Sciences 4 (5): 26–34. 40 Alvarado‐Nava, M.D., Velasquez‐Valle, R., and Meno‐Covarrubias, J. (2006). Cosecha, postcosecha y productos agroindustriales de chile seco. In: Cosecha, postcosecha y productos agroindustriales de chile seco (eds. A.G. Bravo‐Lozano, G. Galindo‐González and M.D. Amador‐Ramírez), 195–221. México City: Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias. 41 Ros, A., Pascual, J.A., Ayuso, M. et al. (2012). Salidas valorizables de los residuos y subproductos orgánicos de la industria de los transformados de frutas y hortalizas: proyecto Life + Agrowaste. Residuos Revista Técnica 22 (130): 28–35. 42 Romo‐Hualde, A., Yetano‐Cunchillos, A.I., González‐Ferrero, C. et al. (2012). Supercritical fluid extraction and microencapsulation of bioactive compounds from red pepper (Capsicum annuum L.) by‐products. Food Chemistry 133 (3): 1045–1049. 43 Mckee, L. (1998). Chile Skins as a Fiber Source. NMSU Chile Conferences. 44 Meghvansi, M.K., Siddiqui, S., Khan, M.H. et al. (2010). Naga chilli: a potential source of capsaicinoids with broad‐spectrum ethnopharmacological applications. Journal of Ethnopharmacology 132 (1): 1–14. 45 Thomas, M., Badr, A., Desjardins, Y. et al. (2018). Characterization of industrial broccoli discards (Brassica oleracea var. italica) for their glucosinolate, polyphenol and flavonoid contents using UPLC MS/MS and spectrophotometric methods. Food Chemistry 245: 1204–1211. 46 Zambelli, R.A., Caroline, B., Pontes, V. et al. (2017). Broccoli and carrot industrial solid waste characterization and application in the bread food matrix. International Journal of Nutrition and Food Sciences 6 (6–1): 9–15. 47 Cacua B.L.F. (2015). Análisis del manejo de residuos sólidos agrícolas en la Nueva Sexta, Cúcuta, Norte de Santander: una propuesta de mejoramiento ambiental. 48 Femenia, A., Robertson, J.A., Waldron, K.W., and Selvendran, R.R. (1998). Cauliflower (Brassica oleracea L), globe artichoke (Cynara scolymus) and chicory witloof (Cichorium intybus) processing by‐products as sources of dietary fibre. Journal of the Science of Food and Agriculture 77 (4): 511–518. 49 AUSVEG (2013). Fact sheet – vegetable waste. Technical Insights 2 https://ausveg. com.au/app/data/technical‐insights/docs/VG12046FS8.pdf. 50 Avilés, R.E., Espinosa, G.J., Renteria, F.J. et al. (2009). Nontraditional available ingredients with potential to be used in gestating sow feeding in the Mexican Bajio. Veterinaria Mexicana 40 (4): 357–370.

259

260

8  Vegetable By-products

5 1 Ferreira, S.S., Passos, C.P., Cardoso, S.M. et al. (2018). Microwave assisted dehydration of broccoli by‐products and simultaneous extraction of bioactive compounds. Food Chemistry 246: 386–393. 52 Wadhwa, M., Bakshi, M.P.S., and Makkar, H.P.S. (2015). Wastes to worth: value added products from fruit and vegetable wastes. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 10 (043): 1–25. 53 Kulkarni, M., Mootey, R., and Lele, S. (2001). Biotechnology in agriculture, industry and environment. Proceedings of the International Conference of SAARC Countries (28–30 December), 24–31. Karad, India: Microbiologists Society. 54 Podsedek, A. (2007). Natural antioxidants and antioxidant capacity of Brassica vegetables: a review. LWT – Food Science and Technology 40 (1): 1–11. 55 Stajčić, S., Ćetković, G., Ćetković‐Brunet, J. et al. (2015). Tomato waste: carotenoids content, antioxidant and cell growth activities. Food Chemistry 172: 225–232. 56 Socaci, S.A., Rugină, D.O., Diaconeasa, Z.M. et al. (2017). Antioxidant compounds recovered from food wastes. In: Funtional Food Improve Health through Adequate Food, 1e (ed. M.C. Hueda), 3–22. IntechOpen. 57 Perea‐Domínguez, X.P., Hernández‐Gastelum, L.Z., Olivas‐Olguin, H.R. et al. (2018). Phenolic composition of tomato varieties and an industrial tomato by‐ product: free, conjugated and bound phenolics and antioxidant activity. Journal of Food Science and Technology. 55 (9): 3453–3461. 58 Kalogeropoulos, N., Chiou, A., Pyriochou, V. et al. (2012). Bioactive phytochemicals in industrial tomatoes and their processing byproducts. LWT – Food Science and Technology 49 (2): 213–216. 59 Ćetković, G., Savatović, S., Čanadanović‐Brunet, J. et al. (2012). Valorisation of phenolic composition, antioxidant and cell growth activities of tomato waste. Food Chemistry 133 (3): 938–945. 60 Meshginfar, N., Sadeghi Mahoonak, A., Hosseinian, F. et al. (2018). Production of antioxidant peptide fractions from a by‐product of tomato processing: mass spectrometry identification of peptides and stability to gastrointestinal digestion. Journal of Food Science and Technology 55 (9): 3498–3507. 61 Bae, H., Jayaprakasha, G.K., Jifon, J., and Patil, B.S. (2012). Variation of antioxidant activity and the levels of bioactive compounds in lipophilic and hydrophilic extracts from hot pepper (Capsicum spp.) cultivars. Food Chemistry 134 (4): 1912–1918. 62 Loizzo, M.R., Pugliese, A., Bonesi, M. et al. (2015). Evaluation of chemical profile and antioxidant activity of twenty cultivars from Capsicum annuum, Capsicum baccatum, Capsicum chacoense and Capsicum chinense: a comparison between fresh and processed peppers. LWT – Food Science and Technology 64 (2): 623–631. 63 Silva, L.R., Azevedo, J., Pereira, M.J. et al. (2013). Chemical assessment and antioxidant capacity of pepper (Capsicum annuum L.) seeds. Food and Chemical Toxicology 53: 240–248.

 ­Reference

6 4 Tundis, R., Loizzo, M.R., Menichini, F. et al. (2011). Comparative study on the chemical composition, antioxidant properties and hypoglycaemic activities of two Capsicum annuum L. cultivars (Acuminatum small and Cerasiferum). Plant Foods for Human Nutrition 66 (3): 261–269. 65 Sandoval‐Castro, C.J., Valdez‐Morales, M., Oomah, B.D. et al. (2017). Bioactive compounds and antioxidant activity in scalded Jalapeño pepper industrial byproduct (Capsicum annuum). Journal of Food Science and Technology 54 (7): 1999–2010. 66 Hsia, S.‐M., Lee, W.‐H., Yen, G.‐C., and Wu, C.‐H. (2016). Capsaicin, an active ingredient from chilli peppers, attenuates glycative stress and restores sRAGE levels in diabetic rats. Journal of Functional Foods 21: 406–417. 67 Abid, Y., Azabou, S., Jridi, M. et al. (2017). Storage stability of traditional Tunisian butter enriched with antioxidant extract from tomato processing by‐ products. Food Chemistry 233: 476–482. 68 Osuna‐Garcia, J.A. and Wall, M.M. (2007). Prestorage moisture content affects color loss of ground paprika (Capsicum annuum L.) under storage. Journal of Food Quality 21 (3): 251–259. 69 Huynh, N.T., Smagghe, G., Gonzales, G.B. et al. (2014). Enzyme‐assisted extraction enhancing the phenolic release from cauliflower (Brassica oleracea L. var. botrytis) outer leaves. Journal of Agricultural and Food Chemistry 62 (30): 7468–7476. 70 Mithen, R.F., Dekker, M., Verkerk, R. et al. (2000). The nutritional significance, biosynthesis and bioavailability of glucosinolates in human foods. Journal of the Science of Food and Agriculture 80 (7): 967–984. 71 Liu, M., Zhang, L., Ser, S.L. et al. (2018). Comparative phytonutrient analysis of broccoli by‐products: the potentials for broccoli by‐product utilization. Molecules 23 (4): 900. https://doi.org/10.3390/molecules23040900. 72 Blanco‐Díaz, M.T., Del Río‐Celestino, M., Martínez‐Valdivieso, D., and Font, R. (2014). Use of visible and near‐infrared spectroscopy for predicting antioxidant compounds in summer squash (Cucurbita pepo ssp pepo). Food Chemistry 164: 301–308. 73 Mongkolsilp, S., Pongbupakit, I., Sae‐Lee, N., and Sitthihaworm, W. (2004). Radical scavenging activity and total phenolic content of medicinal plants used in primary health care. Thai Pharmaceutical and Health Science Journal 9 (1): 32–35. 74 Rotimi, S.O., Rotimi, O.A., and Obembe, O.O. (2014). In silico analysis of compounds characterized from ethanolic extract of Cucurbita pepo with NFκB‐ inhibitory potential. Bangladesh Journal of Pharmacology 9 (4): 551–556. 75 Martínez‐Valdivieso, D., Font, R., Fernández‐Bedmar, Z. et al. (2017). Role of zucchini and its distinctive components in the modulation of degenerative processes: Genotoxicity, anti‐genotoxicity, cytotoxicity and apoptotic effects. Nutrients 9 (7): 755. https://doi.org/10.3390/nu9070755.

261

262

8  Vegetable By-products

7 6 Mondal, S., Hossain, I., and Islam, N. (2017). Determination of antioxidant potential of Cucurbita pepo Linn. (an edible herbs of Bangladesh). Journal of Pharmacognosy and Phytochemistry 6 (5): 1016–1019. 77 Mondal, S., Hossain, I., and Islam, N. (2017). Phytochemical screening of ethanolic extract of leaves and stems of Cucubita pepo Linn. International Journal of Chemistry Studies 1 (2): 32–34. 78 Perez Gutierrez, R.M. (2016). Review of Cucurbita pepo (pumpkin) its Phytochemistry and pharmacology. Medicinal Chemistry 6 (1): 12–21. 79 Nema, N.K., Maity, N., Sarkar, B., and Mukherjee, P.K. (2011). Cucumis sativus fruit potential antioxidant, anti‐hyaluronidase, and anti‐elastase agent. Archives of Dermatological Research 303 (4): 247–252. 80 Abu‐Reidah, I.M., Arráez‐Román, D., Quirantes‐Piné, R. et al. (2012). HPLC‐ESI‐Q‐ TOF‐MS for a comprehensive characterization of bioactive phenolic compounds in cucumber whole fruit extract. Food Research International 46 (1): 108–117. 81 Kumar, D., Kumar, S., Singh, J. et al. (2010). Free Radical Scavenging and Analgesic Activities of Cucumis sativus L. Fruit Extract. Pharmacognosy Free 2 (4): 365–368. 82 Patil, M.V.K., Kandhare, A.D., and Bhise, S.D. (2012). Effect of aqueous extract of Cucumis sativus Linn. Fruit in ulcerative colitis in laboratory animals. Asian Pacific Journal of Tropical Biomedicine 2 (2): S962–S969. 83 John, S., Priyadarshini, S., Monica, S.J. et al. (2018). In vitro antioxidant and antimicrobial properties of Cucumis sativus peel extracts. International Research Journal of Pharmacy 9 (1): 56–60. 84 Garg, V.K. and Nes, W.R. (1986). Occurrence of Δ5‐sterols in plants producing predominantly Δ7‐sterols: studies on the sterol compositions of six cucurbitaceae seeds. Phytochemistry 25 (11): 2591–2597. 85 Rice, C.A., Rymal, K.S., Chambliss, O.L., and Johnson, F.A. (1981). Chromatographic and mass spectral analysis of Cucurbitacins of three Cucumis sativus cultivars. Journal of Agricultural and Food Chemistry 29 (1): 194–196. 86 Chen, X., Bao, J., Guo, J. et al. (2012). Biological activities and potential molecular targets of cucurbitacins: a focus on cancer. Anti‐Cancer Drugs 23 (8): 777–787. 87 Mcnally, D.J., Wurms, K.V., Labbe, C., and Be, R.R. (2003). Complex C – glycosyl flavonoid Phytoalexins from Cucumis sativus. Journal of Natural Products 66 (9): 1280–1283. 88 Kai, H., Baba, M., and Okuyama, T. (2007). Two new megastigmanes from the leaves of Cucumis sativus. Chemical and Pharmaceutical Bulletin 55 (1): 133–136. 89 De Marino, S., Borbone, N., Zollo, F. et al. (2004). Megastigmane and phenolic components from Laurus nobilis L. leaves and their inhibitory effects on nitric oxide production. Journal of Agricultural and Food Chemistry 52 (25): 7525–7531. 90 Kaushik, U., Aeri, V., and Mir, S.R. (2015). Cucurbitacins – an insight into medicinal leads from nature. Pharmacognosy Reviews 9 (17): 12–18.

 ­Reference

9 1 Tang, J., Meng, X., Liu, H. et al. (2010). Antimicrobial activity of sphingolipids isolated from the stems of cucumber (Cucumis sativus L.). Molecules 15 (12): 9288–9297. 92 Mallik, J. and Akhter, R. (2012). Phytochemical screening and in‐vitro evaluation of reducing power, cytotoxicity and anti‐fungal activities of ethanol extracts of Cucumis sativus. International Journal of Pharmaceutical & Biological Archives 3 (3): 555–560. 93 Taveira, M., Silva, L.R., Vale‐Silva, L.A. et al. (2010). Lycopersicon esculentum seeds: an industrial byproduct as an antimicrobial agent. Journal of Agricultural and Food Chemistry 58 (17): 9529–9536. 94 Moayedi, A., Mora, L., Aristoy, M.C. et al. (2018). Peptidomic analysis of antioxidant and ACE‐inhibitory peptides obtained from tomato waste proteins fermented using Bacillus subtilis. Food Chemistry 250: 180–187. 95 Meshginfar, N., Sadeghi Mahoonak, A., and Hosseinian, F.T.A. (2018). Physicochemical, antioxidant, calcium binding, and angiontensin converting enzyme inhibitory properties of hydrolyzed tomato seed proteins. Journal of Food Biochemistry 43: e12721. https://doi.org/10.1111/jfbc.12721. 96 Yang, T., Yang, X., Wang, X. et al. (2013). The role of tomato products and lycopene in the prevention of gastric cancer: a meta‐analysis of epidemiologic studies. Medical Hypotheses 80 (4): 383–388. 97 Prasad, B.C.N., Shrivastava, R., and Ravishankar, G.A. (2005). Capsaicin. Evidence‐Based Integrative Medicine 2 (3): 147–166. 98 Bekhit, A.E.D., Lingming, K., Mason, S.L. et al. (2013). Upgrading the utilization of brassica wastes: physicochemical properties and sensory evaluation of fermented brassica stalks. International Food Research Journal 20 (4): 1961–1969. 99 Nilius, B. and Appendino, G. (2013). Spices: the savory and beneficial science of pungency. Reviews of Physiology, Biochemistry and Pharmacology 164: 1–76. 100 Zsombok, A. (2013). Vanilloid receptors—do they have a role in whole body metabolism? Evidence from TRPV1. Journal of Diabetes and its Complications 27 (3): 287–292. 101 Guarini, G., Ohanyan, V.A., Kmetz, J.G. et al. (2012). Disruption of TRPV1‐ mediated coupling of coronary blood flow to cardiac metabolism in diabetic mice: role of nitric oxide and BK channels. American Journal of Physiology‐ Heart and Circulatory Physiology 303 (2): H216–H223. 102 Turnbaugh, P.J., Ley, R.E., Mahowald, M.A. et al. (2006). An obesity‐associated gut microbiome with increased capacity for energy harvest. Nature 444: 1027. 103 Sung, J., Bang, M.‐H., and Lee, J. (2015). Bioassay‐guided isolation of anti‐ adipogenic compounds from defatted pepper (Capsicum annuum L.) seeds. Journal of Functional Foods 14: 670–675. 104 Imran, M., Butt, M.S., and Suleria, H.A.R. (2018). Casicum annuum bioactive compounds: health promotion perspectives. In: National Institute of Food

263

264

8  Vegetable By-products

105

106

107 108

109

110

111

112

113

114 115

116

117

Science and Technology (eds. K.‐M. Mérillon and K.G. Ramawat), 1–22. Switzerland: Springer International Publishing. Sim, K.H. and Sil, H.Y. (2008). Antioxidant activities of red pepper (Capsicum annuum) pericarp and seed extracts. International Journal of Food Science & Technology 43 (10): 1813–1823. Deepa, N., Kaur, C., Singh, B., and Kapoor, H.C. (2006). Antioxidant activity in some red sweet pepper cultivars. Journal of Food Composition and Analysis 19 (6–7): 572–578. Munir, A., Sultana, B., Bashir, A. et al. (2018). Evaluation of antioxidant potential of vegetables waste. Polish Journal of Environmental Studies 27 (2): 947–952. Xu, Y., Li, Y., Bao, T. et al. (2017). A recyclable protein resource derived from cauliflower by‐products: potential biological activities of protein hydrolysates. Food Chemistry 221: 114–122. Montone, C.M., Capriotti, A.L., Cavaliere, C. et al. (2018). Characterization of antioxidant and angiotensin‐converting enzyme inhibitory peptides derived from cauliflower by‐products by multidimensional liquid chromatography and bioinformatics. Journal of Functional Foods 44 (34): 40–47. Morales‐Soto, A., García‐Salas, P., Rodríguez‐Pérez, C. et al. (2014). Antioxidant capacity of 44 cultivars of fruits and vegetables grown in Andalusia (Spain). Food Research International 58: 35–46. Hamissou, M., Smith, A.C., Carter, R.E., and Triplett, J.K. (2013). Antioxidative properties of bitter gourd (Momordica charantia) and zucchini (Cucurbita pepo). Emirates Journal of Food and Agriculture 25 (9): 641–647. Dixit, Y. and Kar, A. (2010). Protective role of three vegetable peels in Alloxan induced diabetes mellitus in male mice. Plant Foods for Human Nutrition 65 (3): 284–289. Patil, M.V.K., Kandhare, A.D., and Bhise, S.D. (2011). Pharmacological evaluation of ameliorative effect of aqueous extract of Cucumis sativus L. fruit formulation on wound healing in Wistar rats. Chronicles of Young Scientists 2 (4): 207–213. Sudheesh, S. and Vijayalakshmi, N.R. (1999). Lipid‐lowering action of pectin from Cucumis sativus. Food Chemistry 67 (3): 281–286. Minaiyan, M., Zolfaghari, B., and Kamal, A. (2011). Effect of hydroalcoholic and buthanolic extract of Cucumis sativus seeds on blood glucose level of normal and Streptozotocin‐induced diabetic rats. Iranian Journal of Basic Medical Sciences 14 (5): 436–442. Gill, N.S., Grag, M., Bansal, R. et al. (2009). Evaluation of antioxidant and antinulcer potential of Cucumis sativum L. seed extract in rats. Asian Journal of Clinical Nutrition 1 (3): 131–138. Agarwal, M., Kumar, A., Gupta, R., and Upadhyaya, S. (2012). Extraction of polyphenol, flavonoid from Emblica officinalis, Citrus limon, Cucumis sativus and evaluation of their antioxidant activity. Oriental Journal of Chemistry 28 (2): 993–998.

 ­Reference

1 18 Jevtić, B., Djedović, N., Stanisavljević, S. et al. (2017). Anti‐encephalitogenic effects of cucumber leaf extract. Journal of Functional Foods 37: 249–262. 119 Venturi, F., Sanmartin, C., Taglieri, I. et al. (2017). A simplified method to estimate Sc‐CO2 extraction of bioactive compounds from different matrices: chili pepper vs. tomato by‐products. Applied Sciences 7 (4): 361. https://doi. org/10.3390/app7040361. 120 El Ksibi, I., Slama, R.B., Faidi, K. et al. (2015). Mixture approach for optimizing the recovery of colored phenolics from red pepper (Capsicum annuum L.) by‐products as potential source of natural dye and assessment of its antimicrobial activity. Industrial Crops and Products 70: 34–40. 121 Poojary, M.M. and Passamonti, P. (2015). Extraction of lycopene from tomato processing waste: kinetics and modelling. Food Chemistry 173: 943–950. 122 Kehili, M., Schmidt, L.M., Reynolds, W. et al. (2016). Biotechnology for biofuels biorefinery cascade processing for creating added value on tomato industrial by – products from Tunisia. Biotechnology for Biofuels 9: 261. https://doi. org/10.1186/s13068‐016‐0676‐x. 123 Strati, I.F. and Oreopoulou, V. (2011). Effect of extraction parameters on the carotenoid recovery from tomato waste. International Journal of Food Science and Technology 46 (1): 23–29. 124 Pinela, J., Prieto, M.A., Filomena, M. et al. (2017). Valorisation of tomato wastes for development of nutrient‐rich antioxidant ingredients: A sustainable approach towards the needs of the today’s society. Innovative Food Science and Emerging Technologies 41: 160–171. 125 Silva, Y.P.A., Ferreira, T.A.P.C., Celli, G.B., and Brooks, M.S. (2018). Optimization of lycopene extraction from tomato processing waste using an eco‐friendly ethyl lactate–ethyl acetate solvent: a green valorization approach. Waste and Biomass Valorization https://doi.org/10.1007/ s12649‐018‐0317‐7. 126 Robles‐Ramírez, M.C., Monterrubio‐lópez, R., Mora‐escobedo, R. et al. (2016). Evaluation of extracts from potato and tomato wastes as natural antioxidant additives. Archivos latinoamericanos de nutrición 66 (2): 66–73. 127 Karthika, D.B., Kuriakose, S.P., Krishnan, A.V.C. et al. (2016). Utilization of by‐product from tomato processing industry for the development of new product. Journal of Food Processing & Technology 7 (8) https://doi. org/10.4172/2157‐7110.1000608. 128 Mehta, D., Prasad, P., Sangwan, R.S., and Yadav, S.K. (2018). Tomato processing byproduct valorization in bread and muffin: improvement in physicochemical properties and shelf life stability. Journal of Food Science and Technology 55 (7): 2560–2568. 129 Botineştean, C., Gruia, A.T., and Jianu, I. (2014). Utilization of seeds from tomato processing wastes as raw material for oil production. Journal of Material Cycles and Waste Management 17 (1): 118–124.

265

266

8  Vegetable By-products

130 Gang, W., Guang, H., Li, X., and Hua, C. (2000). Process for preparing crystal lycopene and/or lycopene oil resin from tomato paste. CN1298904A, issued 2000. 131 Espinosa García, J. (2006). Method of obtaining lycopene from tomato skings and seeds. WO2006/032712, issued 2006. 132 Lu, Q., Lian, Y., Han, W., et al. (2006). Process for extracting lycopene. US9434886, issued 2006. 133 Perez, L., Mol, C., Bakus II, R.C., et al. (2018). Plant extract compositions for forming protective coatings. US9957215 B2, issued 1 May 2018. 134 Hashimoto, M., Inoue, Y., and Yosuke, W. (2004). Red pepper seed oil and use of the same. JP2004159585A, issued 2004. 135 Chunxi, G. (2005). Industrial production of capsaicin with seed and skin of red hot pepper as material. CN1219750C, issued 2005. 136 Lunwen, S. (2007). Capsicum seed powder condiment. CN101040699A, issued 2007. 137 Juanjuan, D., and Yingjian, L. (2010). Method for producing red pepper seed oil. CN101870918A, issued 2010. 138 Xinyi, H., Wenjiao, S., Yaofang, Y., et al. (2017). Method for preparing pepper seed oil by water enzymatic method. CN107418705A, issued 2017. 139 Stojceska, V., Ainsworth, P., Plunkett, A. et al. (2008). Cauliflower by‐products as a new source of dietary fibre, antioxidants and proteins in cereal based ready‐to‐eat expanded snacks. Journal of Food Engineering 87 (4): 554–563. 140 Alvarez‐Jubete, L., Valverde, J., Kehoe, K. et al. (2014). Development of a novel functional soup rich in bioactive Sulforaphane using broccoli (Brassica oleracea L. ssp. italica) florets and Byproducts. Food and Bioprocess Technology 7 (5): 1310–1321. 141 Drabińska, N., Ciska, E., Szmatowicz, B., and Krupa‐Kozak, U. (2018). Broccoli by‐products improve the nutraceutical potential of gluten‐free mini sponge cakes. Food Chemistry 267: 170–177. 142 Lucera, A., Costa, C., Marinelli, V. et al. (2018). Fruit and vegetable by‐products to fortify spreadable cheese. Antioxidants 7 (5): 61. https://doi.org/10.3390/ antiox7050061. 143 West, L.G., Pomerleau, T., Matusheski, N. V., et al. (2007). Production of Glucosinolates from agricultural by‐products & waste. US20080311276A1, issued 2007. 144 Zhu Bo Zhang Huacheng, Yuan Yuan, Xu He, Z.J. (2018). Cucurbita pepo enzyme and preparation method thereof. CN10804699A, issued 2018.

267

9 Flaxseed By-products B. Dave Oomah (Retired) Formerly with Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, British Columbia, Canada

9.1 ­Introduction Protein is an indispensable component of the human diet with plants providing about 63% of dietary protein for human nutrition. Intake of 1.2–1.5 g protein/kg BW/day (about 15–20 E%) is considered safe and physiologically beneficial, but higher intake levels (2 g protein/kg BW/day ~24% E) may adversely affect kidney function in elderly adults [1]. However, the rise in elevated CO2 is estimated to cause protein deficiency in 1.3% of the global population (122 million) in addition to 662 million people currently deficient in protein, creating considerable additional health burden. Protein concentration is estimated to be 3–17% lower in food crops at elevated CO2, which is expected to reach 550 ppm by 2050 [2]. Maize is the only grain that exhibits little or no nutritional response under elevated CO2 among the three major crops (rice, maize, and wheat). These crops provide 60% of the world’s food energy intake and their global demand is projected to increase 33% by 2050. This lack of dietary diversity may adversely affect our health and the environment. Therefore, FAO recommends diversifying our diets with new crops and previously “forgotten foods,” reformulating to make processed foods healthier, biofortifying staple foods, and supporting local farming, agroecology, and regenerative agriculture [3]. New technology such as gene editing can increase protein content of the predominant food crops (rice, corn, and soy) by regulating specific genetic switch known as transcription factor. The technology is expected to increase soy protein content up to 18%, thereby enabling minimally processed soymeal production comparable to fishmeal by 2023–2025 [4]. The food industry has focused Food Wastes and By-products: Nutraceutical and Health Potential, First Edition. Edited by Rocio Campos-Vega, B. Dave Oomah, and Haydé Azeneth Vergara-Castañeda. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

268

9  Flaxseed By-products

­ evelopment of plant‐based products primarily on soy or wheat protein and pea d protein to a smaller extent. However, other plant‐based protein sources are emerging from chickpeas, lentils, sorghum, and millets [5]. Other initiatives such as the launch of the new industry organization (Plant‐Based Foods of Canada [PBFA]) aims to support the regulatory and marketing interests of Canadian plant food companies that produce and market vegetarian products [6]. Plant‐based foods are an important source of protein popular with consumers due to their health benefits, compatibility with lifestyles (vegetarian, vegan, flexitarian), and sustainability. Canada has invested C$ 950 m (US$ 730 m) in its plant protein industry [6]. Several strategies have been developed to increase/enhance protein utilization from lesser known or unconventional plants, particularly by applying the biorefinery concepts for complete valorization of processing wastes. These strategies include increasing the availability of alternative protein options to consumers, generating feed sources for animal nutrition and adding value to the protein for enhance utilization, new applications, reformulations, or conversion to new products. Some technological challenges include increasing the protein concentration of the coproduct stream by economically separating the nonprotein components, maximizing nutritional and functional benefits of the protein‐enriched product/s, ability to generate peptides exhibiting biological activity, marketability of side streams [7]. The biorefinery concept has been proposed for complete utilization of flax and its components starting from the seed, although protein is not a component under consideration [8]. Flax, an “old world” crop, was domesticated for both food and fiber use; these two divergent uses of the crop have resulted in the development of fiber flax and linseed commonly referred as flaxseed. Flaxseed considered a functional food is one of the richest sources of α‐linolenic acid (ALA) and lignans and also valued for its high quality protein and soluble fiber “mucilage” [9]. World area seeded to flax was 2.76 million hectares producing 2.93 million tons of flaxseed in 2016 based on the latest available data [10]. Canada accounted for 12.2 and 19.8% of that global cultivation and production. In 2018–2019, Canada seeded 0.36 million hectares producing 0.55 million tons of flaxseed, 65% of which is generally exported to 53 countries [11]. Generally, flaxseed contains 45.5% oil, the primary product, and 22% protein (N × 6.25) (dmb) [12], thus globally providing about 0.65 million tons of flaxseed protein annually. Flaxseed meal, the by‐product remaining after oil extraction, is a protein source for livestock feeds, particularly for ruminants. It is also used to modify/ improve the fatty acid composition of egg and meat products, thereby enhancing ­consumer’s health benefits [13]. Oil is industrially obtained either by the prepress solvent or expeller press extraction of flaxseed; expeller press relies solely on mechanical pressure for oil extraction leaving residual oil (typically >5%) in the meal. The mechanical extraction, often known as cold press, involves seed ­cleaning, ­conditioning, flaking, and cooking (75–85 °C, 1 hour)

9.2 ­Flaxseed Protei

before pressing the oil, generally using two sets of expellers. The expeller meal typically contains 31.5% crude protein (N × 6.25), 9.5% crude fiber, approximately 5% fat and 6% ash. The true amino acid digestibility of the seed and expeller meal are 71–87 and 74–88%, respectively. Generally, flaxseed meal (up to 10% of the diet) can be safely fed to animals without adverse effects on performance [13]. Thus, value addition of flaxseed meal as an industrial by‐product/ coproduct is of utmost priority for its utilization.

9.2 ­Flaxseed Protein 9.2.1 Extraction Several strategies have been developed to obtain protein from flaxseed since the classical extraction by Osborne [14]. Flaxseed, unlike other oilseeds, contains mucilage that interferes with protein extraction described very early in the history of flaxseed protein [15, 16]. Protein extraction in most studies use flaxseed as the starting material, although flaxseed meal (commercially cold‐pressed, an industrial by‐product) has not been a frequent source. In fact, the functional properties of commercial flaxseed meal were rarely characterized until our earlier investigations [17]. We showed that foaming capacity, foam stability, and shear‐thinning behavior (typical of polymeric non‐Newtonian solution) of commercial flaxseed meal increase linearly with increase in protein concentration presumably due to increase in the proportion of soluble protein [17]. The principle of varying protein solubility with pH is commonly used in the industry since it is simple and minimizes protein denaturation. The solid‐to‐liquid ratio, number of washes, and temperature can be adjusted for optimal removal of soluble compounds. Soy protein isolates are produced by mixing soy material (flour or meal) with water at pH 9–11, removing the solids by centrifugation, adjusting the supernatant to pH approximately 4 to precipitate protein that can be washed, neutralized and spray dried. A similar alkali (pH 10) extraction followed by isoelectric precipitation (pH 3.8) has been used to obtain protein from defatted cold‐pressed flaxseed or other oilseed meals [18]. Although proteins have been extracted from flax sources (seed, meal, or defatted meal), development of commercial processes have essentially been nonexistent probably because of problems with processing and/or protein quality. We addressed this knowledge gap by developing processing technologies for protein extraction from industrially cold‐pressed flaxseed meal at both the laboratory and pilot scales. In addition, the quality and functionality determinants of these proteins were evaluated to define their performance in functional foods and nutraceuticals as indicators of by‐product valuation. The principles of protein extraction are similar in the laboratory and pilot scales, although there are

269

270

9  Flaxseed By-products Meal+water, adjust to acidic pH, mix

Separate solids and liquids Liquid (water-soluble components) Solids (protein)

Add water, adjust to alkaline pH, mix

Separate solids and liquids

Solids (insolubles)

Liquid (protein)

Precipitate protein at acid pH

Separate solids and liquids

Solids (protein)

Liquid (water-soluble components)

Figure 9.1  General flaxseed protein extraction platform.

­ ifferences in details. Initially, protein from industrially cold‐pressed flaxseed d meal was recovered on a lab‐scale based on its pH solubility (Figure 9.1). The solid (~20% of the starting meal dry weight) obtained at the end of the process is a protein‐enriched fraction (49 vs. 33% in the starting meal) with high fat content (21 vs. 16% in the original meal). The general scheme (Figure 9.1) includes a wash at the initial stage to remove some of the soluble components such as mucilage that facilitates protein recovery; the acid pH prevents protein removal and minimizes its solubility. This step provides insights on various factors affecting protein extraction and yield such as meal:water ratio, mixing time, temperature, number of washes, and pH adjustments. A freeze‐dried flax protein was produced in large amounts (>1 kg) to characterize its functionality and establish parameters for pilot‐scale (5–20 kg meal) processing (Figure 9.2) described below.

9.2 ­Flaxseed Protei Meal Protein (30%), Fat (15%) Water 5N HCl

Acid extraction (1:40 H2O, pH 4.5, 2 h)

Separation

Liquid

Protein (23%) Fat (12%) 0.42 Meal (dm)

Mixing (1:20 solids: H2O, pH 4.5, 2h)

Separation

Liquid

Water

Protein (18%) Fat (33%) 0.06 Meal (dm)

Alkaline extraction (1:10 solids: H2O, pH 10, 2 h) 5 N NaOH Separation

Solids

Protein (23%) Fat (5%) 0.28 Meal (dm)

Acid precipitation (pH 3.5, 5N HCl)

Settling overnight 1°C

Separation

Adjust to pH 7 and freeze dry

Liquid Final Product Protein (65%) Fat (3.7%) 0.16 Meal (dm)

Figure 9.2  Pilot-scale flaxseed protein extraction.

The cold‐pressed flaxseed meal extruded as pellets is ground (cutting mill, 1.65 mm screen) prior to mixing/stirring (2–4.5 in. diameter blade‐type impellers, ~360 rpm). This mixture is further agitated (~1500 rpm) in stainless steel tanks (400 or 550 L). Solid is recovered after transferring the mixture (8 kg/min) from the tank and separated from the liquid (Alfa‐Laval decanter centrifuge, 5696 rpm ~4000g).

271

272

9  Flaxseed By-products

The amount of water is doubled (40 vs. 20 parts) that in the lab scale for acid extraction to improve separation with the decanter centrifuge but reduced for alkaline extraction. Two washes (pH 4) for protein extraction improves processing, reduces fat content of the final protein product, increases the protein content, and enables easier separation of the precipitated protein at pH 3.5 from the liquid. About ⅔ of the mixture volume (pH 3.5) can be separated as liquid compared to only about ½ with one wash due to mucilage removal, thereby favoring protein settling and separation. The overnight settling separates almost ½ the volume of the mixture leaving the rest for separation with nylon bag filters (25 and 55 μm pore size, 7 × 30 in.). Vibratory sieve (Vibroscreen) and basket centrifuges are inefficient in separating meal mixtures since they rely on filtration that is impaired (mitigated) by mucilage in the liquid fraction. Ultrafiltration and diafiltration are also inefficient in concentrating and purifying the protein. The protein product is dried by a conventional method, e.g. freeze drying or spray drying. Dewatering by bag filters prior to spray drying is not essential. Spray drying necessitates blending of the product, the use of a large nozzle aperture and limited run time (30–60 minutes) to avoid caking and clogging of the nozzle. The precipitate from the final step prior to drying can be further processed (pH 10 adjustment [with 5 N NaOH] or 0.8 M NaCl addition), acid precipitated (pH 3.8 with 5 N HCl), and neutralized (pH ~ 7).

9.2.2 Composition The flaxseed meal industrially cold‐pressed at various times (n = 13) during the year contained high residual fat (14.1 ± 1.7%; range 11.9–16.3% dwb), intermediate protein (32.8 ± 1.8%; range 28.9–35.2 dwb), and low moisture (5.6 ± 0.9; range 3.7–7.3%) (Table 9.1). Protein extraction reduced the fat and carbohydrate contents and water‐binding capacity simultaneously increasing protein and ash contents, gelation, oil‐binding capacity, foaming, and emulsifying properties. The dietary fiber in flaxseed (~28%) consists of ⅔ insoluble and ⅓ soluble fiber, whereas those of the enriched protein fraction (F2W) with 30% total dietary fiber contained higher soluble fiber (54 and 46% of insoluble and soluble fiber, respectively). The enriched flaxseed protein product exhibits some functional properties comparable to the soy protein isolate, Supro 620, particularly the emulsifying and foaming properties and water‐binding capacity. Protein extraction reduced total phenolics (~66 and 33% of the meal content for F2W and F1W, respectively) measured as catechin in 80% methanol extract. Supro 620 had even lower phenolic content than F2W. However, small amount of the lignin secoisolariciresinol diglucoside (SDG) was retained in the protein‐enriched product (16.4 ± 0.3, 16.8 ± 0.2

9.2 ­Flaxseed Protei

Table 9.1  Composition and functional properties of commercial flaxseed meal, flaxseed, and soy proteins. Composition/characteristics

Meal

F2W

F1W

Supro 620

Moisture (%)

0.2

1.3

1.4

4.9

Fat (%)

15.2

0.8

4.6

0.5

Protein (%) (N × 5.41)

30.4

62.4

54.3

75.8

Carbohydrate (%)

39.8

16.3

20.0

nd

Ash (%)

5.5

6.6

7.1

nd

Energy (kJ/100 g)

1723

1557

1644

nd

Color description

Brown

Dark brown

Dark brown

Light tan

L

55.95

53.09

56.54

86.21

a

4.18

3.22

2.33

0.74

b

16.27

13.46

14.50

15.69

Gel appearance

Dense firm

Soft, sponge‐like

Soft, sponge‐like

Dense firm

Minimum gelation concentration (% w/w)

8

12

12

12

Water holding (g H2O/g sample)

9.05

4.97

5.87

6.32

Fat absorption (g oil/g sample)

0.99

2.32

2.89

1.59

Foaming capacity (%)

11.1

52.5

58.0

73.3

Foaming stability (%)

33.3

76.7

76.1

63.6

Emulsion capacity (mL oil/ g)

770.8

817.1

922.5

967.4

Emulsion stability (%)

55.5

84.9

90.5

90.5

F2W and F1W – Flax proteins products obtained after two and a single acid wash, respectively, in the pilot plant process. Fat, protein and carbohydrate contents are on “as is” basis. Supro 620 is a soy protein isolate from Protein Technologies International. nd – not determined.

and 11.5 ± 0.4 mg/g SDG for flaxseed meal, F1W and F2W, respectively). The ­antioxidant activity of the 80% methanol extract followed a trend similar to that  of total phenolics (67 and 22% reduction of the meal antioxidant activity, respectively).

9.2.3  Amino Acid Profile The enriched flaxseed protein (F2W) had over twice (2.26×) the amino acid content of the original meal on a weight basis (Table 9.2) due to its higher protein content (twice that of the meal). However, the extraction process had negligible effects on amino acids as evidenced by the proportional changes of amino acids

273

274

9  Flaxseed By-products

Table 9.2  Amino acid profiles of selected flaxseed and soy samples. Amino acids (g/100 g protein) FW2a

GFSb

Flax mealc

Soyd

2.4

1.5

3.1

2.7

Essential amino acids Histidine Isoleucine

4.6

4.1

5

4.8

Leucine

6.7

5.6

7.1

8.1

Lysine

3.4

4.1

4.3

6.7

Methionine + cystine

2.6

1.6

6.8

2.8

Phenylalanine + tyrosine

8.7

4.3

8.4

9.0

Threonine

4.0

3.6

5.1

4.1

1.7

1.4

5.9

5.6

5.6

5.6

5.7

4.5

5.5

4.5

Tryptophan Valine Nonessential amino acids Alanine

a

Arginine

10.6

6.5

11.1

7.7

Aspartic acid

10.3

8.4

12.4

12.1

Glutamic acid

18.9

21.2

26.4

18.9

Glycine

6.2

7.2

7.1

4.4

Proline

5.1

5.5

5.6

Serine

5.0

4.0

5.9

5.3

BCAA (Val + Leu + Ile)

17.2

15.3

17.7

18.5

AAA (Phe + Tyr)

8.7

4.3

8.4

9.0

Fischer ratio (BCAA/AAA)

2.0

3.5

2.1

2.1

Lys/Arg

0.3

0.6

0.39

0.9

Arg + Glu + His

31.9

29.1

40.6

29.3

Met+Cys

2.6

1.6

6.8

2.8

Total essential amino acids

35.8

28.8

44.0

42.5

36.4

41.0

E/T (%)

35.8

35.1

Total amino acids (% wt)

37.53

16.58

Total amino acids (% wt)

37.53

16.58

 FW2 – Flax protein obtained after two acid washes in the pilot plant process.  GFS– Commercial flaxseed meal. c   From [19]. d  Soy protein concentrate from water wash  [20]. Source: adapted from [19, 20]. Reproduced with permission of Elsevier. b

9.2 ­Flaxseed Protei

between the meal and enriched flaxseed protein. Flaxseed protein is generally rich in glutamic acid, aspartic acid, glycine, arginine, leucine, alanine, and phenylalanine and limited in the sulfur amino acids, cysteine, and methionine; this may account for its poor gelling properties since disulfide bonds are an important factor in heat gelation. The high levels of branch‐chained amino acid (BCAA) of the flaxseed protein, similar to those of soy protein, indicate its potential in modulating insulin sensitivity and gut hormones [21]. The low aromatic amino acids and Fisher ratio of flaxseed protein are desirable traits for functional foods to meet specific physiological needs. The Arg + Glu + His value of flaxseed protein similar to those of soy indicates its potential strong effects on body immune functions [9]. The enriched flaxseed protein may be less lipidemic and atherogenic than soy protein evidenced by its low Lys/Arg ratio (Table 9.2). Overall, the enriched flaxseed protein meets the essential amino acid requirements with a good balance of amino acids comparable to soy protein. Flaxseed consists of smaller molecular weight proteins (10, 11, 22, 26, 33, 36, 50, and 60 kDa) compared with those of the soy protein Supro 620 (22, 33, 39, 45, 56, 73, 78, and 155 kDa).

9.2.4  Product Application The enriched flaxseed protein (F1W) was examined as a substitute for soy protein (1 : 1 at 12%) in a sausage‐type product. The flaxseed protein sausage was dark, soft with no resistance, and salty with some off flavors reflecting the color and characteristics of the protein. The salty perception was probably due to the formation of NaCl from acid and alkali addition for pH adjustments. Formulators generally incorporate newer plant proteins by blending with other established and highly consumer‐ accepted proteins, such as soy protein that works well with any flavor profile. The study indicates that flaxseed protein may not pair well with soy protein and blending with other plant protein may likely yield the best flavor outcome. In this regard, sensory mapping may reveal the potential benefits of flaxseed protein through flavor refinement and most importantly by enhancing protein content, generally the most appealing and meaningful “plant protein” attribute to consumers [22]. Furthermore, changes in color during alkaline protein extraction should be minimized or eliminated to add value to the product; this may also reduce off flavor development. The dark green brown protein solution obtained during flaxseed meal extraction (pH ~ 11) is retained in the final high protein product. This color development has been attributed to phenolic oxidation at alkaline pH extraction of oilseed (sunflower and canola) meals. Technologies have recently been developed to upcycle defatted sunflower seed oilcake by eliminating the green color, balancing the amino acid profile, increasing the protein quality, and rendering the protein palatable for human consumption [23]. Various strategies have been evaluated to reduce or eliminate the color produced by large‐scale process for the isolation of high flax protein meal. Peroxide (30% H2O2 for final 0.2, 0.5 and 1% [v/v] concentration)

275

276

9  Flaxseed By-products

treatment reduced color development, whereas sodium sulfite (0.025 and 0.125 g/L Na2SO3) and oxygen exclusion (10 minutes N2 flush) had negligible or no effect. The null effect of oxygen exclusion (nitrogen sparging) indicates that phenolic oxidation under alkaline conditions may not be responsible for color development in flaxseed meal. H2O2 is approved for organic processing, but its reactions with proteins and other components in meals are not fully understood. Dehulled flaxseed changes only slightly in color when exposed to alkaline condition (pH 11) and may be used as an alternative source for protein extraction. Proteins produced by enzyme treatment of the defatted flaxseed meal (1 part ­flaxseed meal + 9 parts water containing 2% Viscozyme, mixed at 50 °C, 3 hours, inactivated at 65 °C, 15 minutes) display a light yellow color and composition comparable with those of the soy protein Supro 620. Furthermore, enzyme pretreatment increased protein yield compared to acid wash (44 vs. 15%) of the starting meal protein probably due to improved protein solubilization by the enzyme and/or the heating required for its activation. Both acid wash (pH 4.5) and enzyme treatment (2% Viscozyme) remove mucilage from flaxseed meal, enabling high yield protein extraction with desirable color, but different functional properties. A recent study confirms that flax addition displays the lowest sensory scores compared to control similar to those observed with flaxseed addition (up to 6%) in hamburgers. However, the high quality protein of flaxseed in combination with its omega‐3 fatty acid and other bioactives may be beneficial in developing special food products to prevent sarcopenia for the elderly population [24].

9.3 ­Advanced Processing A similar process to our pilot plant extraction was used to obtain flaxseed protein isolate (30% yield, protein weight basis) but started with fiber hydrolysis (1% cellulase, w/w; 37 °C, 4 hours, pH 5.0) [25]. The cellulase treatment reduces viscosity of the aqueous flaxseed meal suspension, thereby improving protein solubilization in alkaline medium. It produces a flaxseed protein isolate (12% dry weight yield, 78.9% protein) representing a 22.7% increase in protein content compared to control (61% protein) under similar conditions. A product (55.4% protein) is obtained when acidified water (pH 4.2, 1 hour) is used to remove mucilage. The protein isolate can be hydrolyzed by enzymes (pepsin, ficin, trypsin, papain, thermolysin, pancreatin, Alcalase) to produce peptides of variable antioxidant properties that may be useful in attenuating oxidative stress or lipid peroxidation, thereby enhancing food shelf life. Cellulase (2% w/w, 37 °C, 4 hours) pretreatment has also been used to extract protein from hexane extracted cold‐pressed flaxseed meal prior to alkali (5% w/v. 1 M NaOH, pH 9.5) extraction followed by acid precipitation (1 M HCl, pH 4.0). Further alcohol precipitation (95% ethanol, overnight 4 °C) of

9.4 ­Mucilag

the alkali extracted protein yielding three fractions: protein concentrate, mucilage, and residue. The protein contents (N × 6.25) were 86.8 and 51.1% for the ethanol precipitated and alkali extracted proteins, respectively [26]. Mucilage content can also be reduced by treating flaxseed with Viscozyme (22.5 mg protein/100 g, 1 : 5, w/v 0.01 M acetate buffer pH 4, 40 °C, 3–6 hours) [27]. Apparently, pectinase‐based enzyme such as Viscozyme (10 mL/L, 50 °C, 1.5 hours, meal concentration 0.2 g/ mL) hydrolyzes mucilage evidenced by considerable release of phenolics and proteins, generally improved in ethanol presence [28]. Viscozyme (2%, ~50 °C, 3 hours) pretreatment increased protein recoveries with lower purity compared to the acid wash process to remove mucilage where 26% protein is lost in the starting meal. Furthermore, the final protein obtained with enzyme treatment has low lignan (SDG) content compared to acid wash protein (6 vs. 60 mg SDG/g) [29].

9.4 ­Mucilage Mucilage, an important component of flaxseed, interferes with protein extraction and hinders flaxseed meal’s protein absorption, thereby reducing feed efficiency in monogastric animals. It is a predominant constituent of the five distinct layers of flaxseed seed coat or hull accounting for 2–7.5% of the seed dry weight [30, 31]. Flaxseed mucilage and hull content have broad phenotypic variation with high and moderate (~70 and ~49%) narrow sense heritability, respectively, in diverse genotypes. These complex traits (mucilage and hull content) are predominantly regulated/modulated by seven and four quantitative trait loci (selective gene expression) [32]. Therefore, flaxseed cultivars can be developed differing in mucilage and hull contents for food and feed; although seed coat thickness or hull content is inversely associated with seed oil and protein content. Various processing aspects have been described for dietary fiber, mucilage, and/ or hull extraction from flaxseed [15]. Extraction conditions affect the antioxidant activity of flaxseed mucilage/gum considerably due to retention of phenolic compounds [33]. Flaxseed hull, a low‐valued coproduct of flax processing, is now commercially available and represents a potential source of value‐added healthy products. For example, oil (18.2% yield) obtained from commercial flaxseed hulls consisted primarily of neutral lipids (92.5%) with minor amounts of free fatty acids, phospholipids, and acidic lipids (2.1, 3.1, and 2.4% of the crude oil, respectively). Furthermore, supercritical CO2 extraction delivered both α‐linolenic acid and antioxidant benefits of flaxseed hulls leaving behind a valuable “solvent‐free” secondary product with high SDG (53 mg/g) content [34]. We developed a simple, economical, and scalable process to produce dietary fiber products from flaxseed hulls [35]. The process comprises cleaning (sieves), hot aqueous extraction (steam 85–95 °C, 2–3 hours), separation (sieves), drying, and

277

278

9  Flaxseed By-products

milling. It produces two major products that can replace 5–10% wheat flour in bakery products. The products have 54–60% dietary fiber with over 90% insoluble fiber, 3% SDG (wt), 14–19% protein, and 50–180 mg of ALA. The products increase dietary fiber in whole wheat bread (4–6%), with ALA content (7–14×) and antioxidant activity (1.5×), and positively alter the polyunsaturates‐to‐saturates ratio. The SDG of the products ( ⃒ 60 mg/2 g product) can significantly alter estradiol metabolism to impact tissue estrogen exposure and subsequent breast cancer [36]. The dietary fiber extracted from flaxseed hulls reduced apparent energy and fat digestibility, leading to restriction of body weight gain in growing rats [37]. It suppressed postprandial lipemia and appetite and increased satiety without affecting gut hormones (ghrelin, cholecystokinin, and glucagon‐like peptide I) levels in young men [38]. A similar flax dietary fiber extract is now commercially produced in China (Biogin Biochemicals Ltd.) and in Canada (Natunola Health Inc., Ontario) and has been proven to suppress appetite and food intake [39]. Earlier studies showed that Flax fiber (FibrOmega [supplement] or BakeOmega [cold‐pressed flax meal]) containing 56 and 44% soluble and insoluble fiber, respectively, taken orally (17 g fiber/ day) or baked in a bakery product (43 g of flax fiber per loaf) significantly reduced glycemic response in healthy subjects [40]. Consumption of flaxseed fiber added to bread (5 g flaxseed fiber daily for one week) increased fecal excretion of fat and lowered total and LDL‐cholesterol markedly in diabetic adults (7 M + 9 F; average age 24.8 years; BMI 23.8 kg/m2) [41]. Approximately 80% of the polyphenols, found mainly in flaxseed seed coat or hulls, can be efficiently extracted by pulsed electric fields (PEF), a nonthermal environmentally friendly technique [42]. Proteins can also be purified from flaxseed hulls by ultrafiltration of supernatants obtained after acid coagulation [43]. Flaxseed hull is also rich in herbacetin (8‐hydroxy kaempferol also known as 3,5,7,8,4′‐pentahydroxyflavone) diglucoside contributing 5.7% (w/w) to the lignin macromolecule [44]. Herbacetin is structurally similar to quercetin and kaempferol exerting pharmacologically relevant antioxidant, anti‐inflammatory, and anticancer effects. It is commercially available as a crystalline solid and has been used in many studies demonstrating its anticancer effect in several skin cancers and colon cancer (ornithine decarboxylase inhibitor), anti‐inflammatory properties (against TNF‐α, IL‐1β, and cellular NO), and anti‐hyperglycemic and anti‐ hyperlipidemic activities against high fat diet induced T2DM [45].

9.5  ­Current Trends and Perspectives Early studies focused on one of the major components of flaxseed, its unprecedented α‐linolenic acid‐rich oil that is a thriving commercial product. Many health benefits have been and continue to be associated with flaxseed oil, particularly

9.5  ­Current Trends and Perspective

by establishing mechanisms of its antiatherogenic, anti‐inflammatory, and antiproliferative effects [46]. The anti‐inflammatory effects of flaxseed oil (6 g daily for eight weeks) was presumably responsible for the significant reduction (p 1 Mix linoleic, palmitic, and oleic acids/ polyhydroxylalkanoates–biodegradable synthetic polymer

Figure 11.5  Value-added products/sustainability of the coffee agro-industry. Source: from [7]. Reproduced with permission of Elsevier.

Table 11.1  Proximal analysis on spent coffee grounds (carbohydrates, lipids, proteins, and total fiber). Insoluble fiber

Soluble fiber

References

51.54 ± 2.4

50.82 ± 2.5

0.71 ± 0.3

[18]

57.4–69.4

53.9–57.8

52.8–56.8

0.8–1.6

[8, 17, 19]

71.4 ± 6.3

54.6 ± 4.3

47.1 ± 2.9

6.3 ± 1.0

[4]

82

60.5

NR

NR

[3]

SCG

Proteins

Lipids

Carbohydrates Total fiber

Coffea arabica beans (Dark roasted‐SCG, Chiapas, México)

17.99 ± 0.2

16.54 ± 0.4 59.02 ± 1.1

Coffea arabica beans (Medium roasted‐SCG, México)

15.8–16.3

12.1–18.1

Coffea arabica (Roasted‐SCG, Granada, Spain)

13.6 ± 1.3

1.6 ± 0.3

SCG

13.6

 6

NR, not reported; SCG, spent coffee grounds. Source: reproduced with permission of Elsevier.

0004467238.INDD 335

11/6/2019 6:27:16 PM

336

11  Health Benefits of Spent Coffee Grounds

c­ ontains 46.8% mannose, 30.4% galactose, 19% glucose, and 3.8% arabinose, man­ nans being the major polysaccharides [7].

11.5.2  Proteins Proteins are the second macronutrient found in SCG [15]. The amount of protein in SCG varied from 13.6 to 17% (Table 11.1) [8, 9, 14] depending on the prepara­ tion process. Protein concentration in SCG gives a possibility to use this by‐prod­ uct in the feed industry [1]. The protein SCG is a source of essential and nonessential amino acids such as leucine, phenylalanine, valine, isoleucine, argi­ nine, cysteine, glutamine, histidine, aspartic acid, lysine, phenylalanine, serine, and threonine. The essential amino acids represent approximately 49% of the total content of aminoacids in SCG. The protein of SCG has been suggested as viable for the elaboration of products destined to patients with liver diseases, hyperten­ sion, and oxidative stress [7]. The protein content in SCG is higher than in the coffee bean due to SCG retaining the non‐extracted components that are not released during the instant coffee preparation [14]; however, coffee roasting reduces the protein and ash contents in SCG. Most SCG amino acid content, except arginine, aspartic acid, lysine, phenylalanine, serine, and threonine, is con­ siderably higher than that reported in coffee pulp.

11.5.3  Lipids The lipid fraction of green coffee beans is mainly composed of triacylglycerols, sterols, tocopherols, and diterpenes of the kaurene family, the latter comprising up to 20% of the total lipids [6]. High lipid content in the SCG induces peroxida­ tion in the colon which helps to produce or favor the cellular apotosis of cancer cells [18]. The lipid content of SCG depends on the brewing and extraction method [20] with values around 10–15% [10]. Coffee brews prepared by different methods showed that lipids (90.2%) mainly remaining in the SCG correspond to 84.4% tria­ cylglycerols, 12.3% diterpene alcohol esters, 1.9% sterols, 1.3% polar material, and 0.1% sterol esters. Due to this lipid profile, the coffee oil is commercialized for the industry to generate new business [7]. Green coffee oil, usually obtained by mechanical cold‐pressing and solvent extraction, is industrially used in cosmetics because it helps to maintain the natu­ ral skin humidity [6]. Commercial ethanol (99%) has been used to recover lipids from industrial SCG approximately 25.6% oil (dry weight, petroleum ether extraction). Maximum oil yield (82%) was obtained at 1 : 7 ratio (SCG: alcohol), 75 °C, 1 or 2 hours extraction time, and pretreatment (milling or extrusion) [7]. SCG lipids range (1.6–16.5%) has been reported in Table 11.1 [4, 18].

11.5  ­Nutritional Properties of SC

Diterpenes are isoprene derivatives widely found in living organisms; they are important precursors of many compounds such as sterols, retinol, and phytol and also have significant anti‐inflammatory properties [21]. Several coffee compounds (phenolics such as caffeic and chlorogenic acids [CGAs]; diterpenes: kahweol and cafestol) attenuate oxidative stress [18]. Diterpenes are barely present in filtered coffee extract, because the lipid fraction is immiscible with water enabling it to float on the surface of the water extract, thus being mostly retained in the filter [6].

11.5.4 Minerals The second widespread use of SCG is their application as a composting additive in organic farming due to the presence of minerals [20]. The SCG retain only 39% of minerals since most are easily extracted with hot water during instant coffee prep­ aration [4, 17]. SCG contain minerals such as K, Mg, P, Ca, Na, Fe, Mn, and Cu. The total ash con­ centration in SCG varies from 0.82 to 2.08% [20]. Potassium (K) and calcium (Ca) are the most abundant minerals followed by magnesium (Mg) [7]. Mineral content in SCG of approximately 4.6 [6] and 1.8 and 1.1% [19] have been reported. Coffee is regarded as an important source of Mg, comprising 11% of the SCG minerals [7].

11.5.5  Feed Quality Antinutritional and antiphysiological components (caffeine, tannins, fiber, and lignin) in SCG limit their use in animal feed. SCG is among one of the highest lignin‐containing lignocellulosic feedstocks (Table 11.2). Previous study described SCG as “worthless” ruminant feed due to low in vivo organic matter digestibility, gross energy and digestible energy, and negative metabolizable energy [25]. However, 5% SCG in a grain ration had no detrimental effect on growth perfor­ mance and feed intake, while higher SCG levels reduced growth in dairy cows. SCG (5% wheat flour substitution) in fish feed significantly enhanced growth per­ formance of olive flounder; 10% SCG showed comparable growth to control, while higher inclusion level (15% SCG) decreased growth performance (Table 11.3). Such improvement in growth performance (5% SCG) presumably reflects the pre‐ and probiotic effects of SCG’s polyphenol‐rich dietary fiber that can stimulate the growth of beneficial bacteria (i.e. lactobacilli and bifidobacteria) and inhibits path­ ogenic bacteria (exert antibiotic effect). However, SCG inclusion had no significant effects on plasma, muscle, and liver antioxidants [26]. This pre/probiotic activity of SCG may be beneficial in reducing antibiotics use in animal feed and husbandry. SCG fermentation (Lactobacillus plantarum [ATCC 14917], 70% ­moisture, 37 °C, 48 hours anerobic air tension) increased crude protein (17.5%) and lactic acid (5.83%), and reduced acid detergent insoluble N ­concentration (18%), dry matter

337

338

11  Health Benefits of Spent Coffee Grounds

Table 11.2  Composition of lignocellulosic feedstock. Carbohydrate composition (% dry weight) Feedstocks

Cellulose

Hemicellulose

Lignin

SCGa Spent coffee wasteb

8.6–13.3

30–40

25–33

12.4

39.1

19.8–26.5

Coffee pulp

33.7–36.9

44.2–47.5

15.6–19.1

Rice husk

28.7–35.6

11.96–29.3

15.4–20

Barley hull

34.0

36.0

19.0

Barley straw

36–43

24–33

6.3–9.8

Wheat bran

10.5–14.8

35.5–39.2

8.3–12.5

a

 SCG data from Stylianou et al. [23].  Spent coffee waste data from Ballesteros et al. [11]; Pujol et al. [24]. Source: adapted from Menon and Rao [22]. Reproduced with permission of Springer Nature, Elsevier.

b

Table 11.3  Growth performance of fish Paralichthys olivaceus fed diets for 10 weeks. Control

Weight gain (%) Specific growth rate (%) Feed efficiency (%) Protein efficiency ratio Plasma cholesterol (mg/L)

50.5b 0.73b a

101.6

2.24a a

329

SCG (5%)

67.8a 0.92a a

106.4

SCG (10%)

51.6b 0.74b a

92.9

2.30a

1.99a

ab

ab

211

228

SCG (15%)

29.2c 0.45c 60.4b 1.29b 202b

a,b,c

Values with different letters are statistically different ( 0.05). Source: adapted from Rahimnejad et al. 2015 [26]. Reproduced with permission of Korean Journal Publishing Service.

(39%), and pH (5.57–3.63). Fermented SCG inclusion (10% replacement of basal ram diet) resulted in greater crude protein digestibility (56.8 vs 51.9%) and nitrogen retention (19.7 vs 17.6%) than 10% SCG [27].

11.6 ­Nutraceuticals in SCG Coffee or its components (CGAs, dietary fiber, and melanoidins) may reduce colo­ rectal cancer (CRC) risk, increase colon motility, and antioxidant status by their antimutagenic, antioxidant, and anticarcinogenic effects [18]. It has been shown

11.6  ­Nutraceuticals in SC

that the waste of several products of the food industry, such as SCG, which con­ tains significant amounts of antioxidants helps to reduce free radicals when used as a nutraceutical or as a food supplement [28]. The nutraceutical effect of differ­ ent food compounds has helped patients with different types of diseases to improve their condition with the addition of these products during their treat­ ment [29]. SCG contain significant amounts of antioxidants that could help reduce free radicals when used as a nutraceutical or food supplement [30]. Fiber is the principal component responsible for the antioxidant activity of SCG, and recent studies have proposed SCG as an anti‐inflammatory aid to patients with chronic inflammatory diseases [19].

11.6.1  Dietary Fiber Dietary components that regulate cancer cell proliferation and survival include dietary fiber [30]. Dietary fiber encompasses many macromolecules, exhibiting a wide range of physicochemical properties [28]. Agricultural residues are a great source of dietary fiber, which includes cellulose, hemicelluloses, lignin, pectin, gums, and other polysaccharides. SCG consisting primarily of total dietary fiber have mostly insoluble dietary fiber (54%) [17]. Most components of the coffee beans retained after roasting are rich in phenolic compounds, melanoidins, and dietary fiber. The dietary fiber that exhibits antioxidant properties can be classified as antioxidant dietary fiber [29, 31]. Thus, it can be expected that the soluble die­ tary fiber content in roasted products which includes Maillard reaction compounds can be considered as antioxidant dietary fiber because of the antioxidant properties reported in these compounds [32]. In fact, SCG contains 43% of the total dietary fiber, which makes it a potent precursor of nutraceutical products [21].

11.6.2  Resistant Starch Another important nutraceutical component contained in SCG is resistant starch which is resistant to digestion in the small intestine and remains intact in the upper gastrointestinal tract [19]. One of the benefits of this starch is that it can be used as an ingredient that reinforces the technological characteristics of food products associated with baking, pastries, cookies, and extruded cereals [32]. SCG contain approximately 6% resistant starch [17], and values between 5.6 and 6.2 % have been reported for dark‐roasted and medium‐roasted SCG, respectively [19]. In addition to the nutraceutical properties of the resistant starch, the capac­ ity of biofilm formation has been studied for fruit coating to prevent contamina­ tion by pathogenic microorganisms [29]. From a health point of view, resistant starch is able to modulate nutrient digestibility kinetics, allowing its incorpora­ tion in the design of products with lower glycemic index and lower caloric value energy [32].

339

340

11  Health Benefits of Spent Coffee Grounds

11.6.3  Antioxidant Compounds Antioxidant refers to compounds with free radical scavenging, transition metal chelating activities, and singlet oxygen‐quenching capacity. Many studies pro­ mote the antioxidant properties of coffee [14], which have been associated with the presence of natural substances and those generated during roasting [4]. The antioxidant capacity of SCG is attributed to its phenolic content, as well as antho­ cyanins [30], catechins, and other active compounds such as nicotinic acid, trigo­ nelline, quinolinic acid, tannic acid, pyrogallic acid, caffeine [6], and high‐molecular weight melanoidin compounds formed during coffee roasting [4]. Table  11.4 shows the changes in the phenolic compounds, melanoidin, and total 5‐ caffeoylquinic acid content in coffee brew material prepared at different roasting degrees. Usually the antioxidant capacity of coffee is evaluated using 2,2′‐azino‐bis (3‐ ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) and 2,2‐diphenyl‐1‐picrylhydra­ zyl (DPPH) assays [33]. This antioxidant activity of the SCG can exert physiological and local effects on the colon in adults, and their greater absorption through the cells of the epithelium can provide unique benefits for systemic health in different tissues and organs of the body [14]. Other processes such as lyophilization increase the antioxidant capacity of coffee powder making it suitable as an ingredient or additive in the food industry with conservation of the potential and functional properties. Interest in anthocyanins has emerged due to their possible health ben­ efits as an antioxidant, anticancer, anti‐inflammatory, and hypoglycemic agents and as promoters of insulin sensitivity [5]. In recent studies, desserts have been prepared as biscuits where their antioxidative capacity has been significant

Table 11.4  Melanoidin, total phenolic group, and total 5-caffeoylquinic acid content in coffee brew material prepared at different roasting degrees.

a

Roasting degree

Total melanoidin (Kmix 405 nm)a

Total phenolic group (%w/w)b

Total 5-caffeoylquinic acidc

Green

0.54

48

27.9

Light

2.1

54

6.6

Medium

2.55

55

4.7

Dark

3.01

55

2.5

 Value represents the summary of melanoidins detected in high, intermediate, and low‐ molecular weight coffee brew material. Extinction coefficients Kmix (L/g/cm); b  Expresed as chlorogenic acid equivalents; c  On the basis of dry matter. Source: from [50]. Reproduced with permission of American Chemical Society.

11.7  ­Health Benefits of Spent Coffee Ground

­ robably due to a higher concentration or release of other polyphenolic com­ p pounds. These results suggest the influence of the matrix food formulation on the antioxidant capacity [8]. Caffeoylquinic acids (CQAs) are the main components of the phenolic fraction, whose consumption may result in remarkable health [4] For instance, the total antioxidant capacity of the plasma in human volunteers increased shortly after consumption of coffee brew. A statistically significant increase (7%) has been reported in the plasma antioxidant capacity of blood samples drawn from healthy volunteers 2 hours after consumption of 200‐mL regular coffee brew [32].

11.6.4  Antioxidant Dietary Fiber Coffee fibers possess antioxidant properties. The synergy of antioxidant activity and the fiber complex in coffee by‐products, like few cereals, attribute beneficial effects than just a fiber moiety [1]. Recently, attention has been focused on coffee grounds used as an extraordinary source of bioactive compounds and antioxi­ dants such as polyphenols and antioxidant dietary fiber [17]. Coffee brew contains a high amount of soluble dietary fiber (0.47–0.75 g/100 mL) [6]. The composition of this type of food makes them potentially a good source of health benefits [1]. The dietary fiber of coffee consumed with 84% insoluble fiber and 16% soluble fiber in relation to total dietary fiber exhibits antioxidant properties [19]. SCG con­ tains 43% total fiber (35 and 8% soluble and insoluble, respectively). Furthermore, the coffee fibers from SCG exhibit antioxidant properties: 2.4 mmol of trolox/100 g of dry weight similar to well‐known food antioxidant such as red wine products (43%) and peaches (36%). Therefore, dietary fiber from SCG can be categorized as antioxidant dietary fiber, useful as a potential dietary supplement [7]. This type of fiber can be used to give added value to different foods. The fiber antioxidant proper­ ties can contribute to the reduction or prevention of different types of diseases [14].

11.7 ­Health Benefits of Spent Coffee Grounds As mentioned earlier, the coffee industry is responsible for generating large amounts of residues that contaminate the environment causing ecological prob­ lems to the respective coffee‐producing countries. However, SCG have high amounts of antioxidant compounds, such as caffeine, CGAs, trigonelline, and dit­ erpenes that could be recovered and used as natural food preservatives, additives in cosmetics, and as nutritional supplements. SCG have nutrients and bioactive phytochemicals with diverse preventive potential and therapeutic effects for chronic diseases. Phytochemicals have recently received considerable interest because of their safety and potential positive physiological effects on the human

341

342

11  Health Benefits of Spent Coffee Grounds

body. Even though most of the health‐promoting phytochemicals and nutrients are found in the coffee cherry, 90% of the cherry is discarded during processing as agricultural waste or by‐product [21, 29]. By‐products of coffee fruit and bean pro­ cessing are being considered as potential functional ingredients for the food industry. The coffee husks, peel, and pulp, comprising nearly 45% of the cherry and SCG can represent the other 55% of these by‐products. SCG have been studied mainly for their antioxidant activities and these antioxidants have been associated with health benefits [7]. Because awareness regarding environmental protection and waste reduction is an actual issue, phytochemicals in SCG and their health benefits are being reported and they could be valuable by‐products due to the presence of phenolic compounds. Phenolic compounds exert many physiological activities, such as antioxidant, antimicrobial, antimutagenic, anti‐inflammatory, and antiallergenic and are currently used in the fields of biology, medicine, and food. Thus, competent utilization and value addition to nutritionally rich SCG is being accentuated and obtaining momentum in research [34]. Notwithstanding the foregoing, limited research is available on the health ben­ efits of SCG. Thus, in this section the evidence of health benefits from coffee brew consumption that are related with bioactive compounds contained in SCG is included (Figure 11.6).

11.7.1  Weight Management and Obesity Obesity affects a large fraction of the global population and is an agent that can result in metabolic disorders. Food is the primary factor, particularly those high in energy density such as fat, or in sugar‐sweetened beverages. An abundance of food, low physical activity, and several other environmental factors interact with the genetic susceptibility of the host to produce positive energy balance. The majority of this excess energy is stored as fat. The enlarged fat cells and ectopic fat produce and secrete a variety of metabolic, hormonal, and inflammatory products that produce damage in organs (arteries, heart, liver, muscle, and pancreas) [35]. A study of non‐digested SCG (NDSCG) fraction fermented by human gut flora from lean/normal and overweight female donors demonstrated that NDSCG poly­ phenolic metabolism and bioaccessibility differed between the lean and overweight microbiota during colon fermentation, thereby modulating their cytotoxicity to HT‐29 cells. Metabolites produced by colonic fermentation of SCG by lean micro­ biota (LC50/L/hgf‐NDSCG) trigger apoptosis by reducing oxidative stress mainly via catalase and lipid peroxidation (8‐iso‐prostaglandin F2α) [18]. Fat accumulation is correlated with systemic oxidative stress in humans and mice. The increase of oxi­ dative stress in accumulated fat is an important pathogenic mechanism of obesity‐ associated metabolic syndrome which is responsible for the pathogenesis of many diseases (diabetes, obesity, high cholesterol levels, high pressure, etc.) [36].

Induced HT-29 cell apoptosis ↓ Catalase and 8-iso-prostaglandin F2α [19]

Chemoprotection against colon cancer

Induced SW480 cell apoptosis ↑ Caspase-3 activity and mitochondria dysfunction [18]

Anti-inflammatory [20]

Modulating IL-10, CCL-17, CXCL9, IL-1 and IL-5 cytokines Melanoidins

FRAP, TEAC

Suppressed NO production (55%) in Raw 264.7

Antimicrobial activity [4]

Antioxidant activity [4,8]

O

F co erm lo n ente m ic d b ro bi y ot a

Spent coffee grounds

Producing short-chain fatty acids [20] O OH O

OH

Figure 11.6  Potential health benefits from SCG.

OH

E. Coli Prebiotic activity [4]

S. aureus

↑ Lactobacillum and bifidobacteria

344

11  Health Benefits of Spent Coffee Grounds

SCG contain large amounts of beta‐mannan that can be thermally hydro­ lyzed to mannooligosaccharide (MOS), which has potential application as prebiotic in human and animal feed [37]. There are some investigations of physiological functions of MOS, which support the use of by‐products from coffee industry. A double‐blind designed trial, including obese adults, showed that liquid coffee containing MOS from SCG (3 g/day, 12 weeks) significantly reduced abdominal total, subcutaneous, and visceral fat areas in the MOS group, compared to the control [38]. Recent studies show that coffee by‐products such as SCG and CS and their CGA content are able to significantly inhibit the activity of pancreatic lipase in vitro and can reduce fat accumulation. The short‐chain fatty acids, via fermentation of the insoluble fiber, reduce postprandial glucose responses. The coffee fiber obtained through these by‐products can be used to develop new consumer products with special nutritional needs, such as diabetics or people who are overweight or obese. This is attributable to the high amounts of dietary fiber in SCG and their antioxi­ dant capacity. Dietary fiber can play an important role in weight loss. In addition, dietary fiber can reduce appetite and food intake and consequently decrease caloric intake and body mass index [9]. Bioactive compounds of coffee have also been found in SCG such as ­phenolic compounds (CGA), caffeine, fiber, and minerals [39]. It is known that caffeine increases energy expenditure, while chlorogenic and caffeic acids together with dietary fiber increase satiety; these two effects enhance weight regulation [40].

11.7.2  Cardiovascular Diseases Cardiovascular diseases (CVD) are a leading cause of death around the world, so it is important to recognize the risk factors. To reduce the risk, a healthy diet should be used that includes foods that potentiate weight reduction, reduce sodium con­ sumption, maintain physical activity, mitigate stress, among others [41]. The consumption of polyphenols contained in SCG can promote benefits to human health in the cardiovascular system. Prevention or improvement of circu­ latory disorders such as hypertension and coronary artery disease are some of them. Potent inhibitory action of low‐density lipoprotein oxidation, which is linked to the formation of atherosclerotic plaques that contribute to the develop­ ment of coronary heart disease, is another benefit [42]. SCG have high antioxidant potential, high amounts of dietary fiber, and other compounds such as caffeine. These characteristics can provide cardiovascular health potential. Antioxidant compounds have numerous applications in food, cosmetic, and pharmaceutical areas, because they can protect against chronic and degenerative diseases and decrease the risk factors of CVD [11].

11.7  ­Health Benefits of Spent Coffee Ground

The main component of SCG is fiber [9]. Fiber intake is associated with cardio­ vascular effects and based on current data, it may lower blood pressure, improve serum lipid levels, and reduce indicators of inflammation. US Food and Drug Administration authorizes a health claim that foods meeting specific composi­ tional requirements and containing 0.75–1.7 g soluble fiber per serving can reduce the risk of heart disease. Because of the potential protective role of fiber against diverticulosis, colon cancer, diabetes, and heart disease, a fiber‐enriched enteral formula may be indicated for patients in long‐term enteral feeding [43]. Further­ more, high levels of dietary fiber intake are associated with significantly lower ­prevalence rates for coronary heart diseases, stroke, and peripheral vascular disease. Major risk factors, such as hypertension, diabetes, obesity, and dyslipidemia, are also less common in individuals with the highest levels of fiber consumption. In the analyses of prospective cohort studies, the observed protective effect of dietary fiber intake was very similar to the effects of whole grains but “fellow travelers” with fiber, such as magnesium, other minerals, vitamins, and antioxidants, may have important complementary beneficial effect [44]. Caffeine consumption, at various intake levels, is generally associated with decreased CVD risk (in almost half of the available studies), even at intakes above 600 mg of caffeine per day. Only one study shows an increased risk of CVD, while most well‐conducted studies suggest that caffeine consumption is not associated with an increased CVD risk, and may even be protective against CVD [45].

11.7.3  Gastrointestinal Diseases The digestive process plays a decisive role in the release of compounds of interest in health and disease. The pathogenesis of various gastrointestinal diseases such as irritable bowel syndrome and inflammatory bowel disease is in part due to oxi­ dative stress. The intake of antioxidant dietary fiber has been recommended for health improvement of the gastrointestinal tract. Antioxidant compounds may be beneficial at reducing the risk of these gastrointestinal diseases [9, 44]. A study shows that SCG extracts have a high amount of CGA compared with brew; both were stable under gastrointestinal conditions in vitro (oral, gastric, and intestinal) and also with similar bioaccessibility. Spent coffee extracts may, there­ fore, be suitable commercial source of CGAs as ingredients in functional foods or supplements [46]. Transportation of dietary antioxidants through the gastrointestinal tract has been described as an essential function of dietary fiber. Polyphenols linked to dietary fiber may be released in the colon by the action of the microbiota, produc­ ing bioactive metabolites and an antioxidant environment, thereby reducing the risk of gastrointestinal diseases associated with oxidative stress and inflamma­ tion. CGA, which is present in the coffee fiber, has shown potential to inhibit

345

346

11  Health Benefits of Spent Coffee Grounds

signaling molecules involved in inflammation processes, thereby acting as an anti‐inflammatory antioxidant compound [9, 47]. Moreover, previous studies have reported an association of antioxidants, in par­ ticular polyphenols, with α‐glucosidase inhibition. The release of phenolic com­ pounds incorporated into the coffee fiber structure during the digestion process may enhance tolerance to carbohydrates by inhibiting intestinal α‐glucosidase. Diterpenes, such as cafestol and kahweol, present in SCG can contribute to this inhibitory effect on α‐glucosidase exerted by the novel biscuits. Alpha‐glucosidase inhibitors reduce the impact on blood sugar and therefore postprandial hypergly­ cemia [9]. The coffee fiber stimulates the gut serotonin and GLP‐1 hormones ex vivo in Caco‐2 and HuTu‐80 cells, respectively. These intestinal hormones can regulate the feeling of fullness via neural paracrine routes with subsequent afferent signal­ ing to brainstem nuclei. GLP‐1 also regulates the feeling of fullness via the endo­ crine pathway through the hepatic portal and cava vein. The intestinal secretion of serotonin responds to chemical and mechanical stimuli after food intake. Thus, the antioxidant coffee fiber is expected to exhibit a greater stimulation of satiety hormones in vivo, due to the physical effect of the indigestible material obtained from the digestive process. The secretion of GLP‐1 hormone also participates in glycemic tolerance via glucose‐induced secretion of insulin [9].

11.7.4  Cancer The fermented nondigestible fraction of SCG induces apoptosis in human colon cancer cells (SW480). These anticancer activities may be due to the synergistic actions of bioactive compounds present in nondigestible/unabsorbed fraction of SCG [17]. Furthermore, the human gut fermented nondigestible fraction (NDSCG) using lean/normal microbiota effectively regulates apoptosis by attenuating oxi­ dative stress in human colon adenocarcinoma HT‐29 cells [18]. As mentioned before, coffee by‐products such as SCG contain CGA, a major component of green coffee seeds. The consumption of CGA may result in remark­ able health benefits such as in different types of cancer. CGA is absorbed and metabolized throughout the gastrointestinal tract [17, 21]. Recently, the anti‐ inflammatory activity of polyphenols has been widely recognized. These phenolic compounds are beneficial against oxidative stress and inflammation‐related dis­ eases. The European Prospective Investigation into Cancer and Nutrition (EPIC) study of 36 037 individuals evaluated the consumption of different sources of phe­ nolic acids and found that coffee was the main food source of phenolic acids com­ pared to fruits, vegetables, and nuts. A cross‐sectional study of 2554 male and 763 female Japanese workers showed that coffee intake was negatively associated with blood leptin, triacylglycerols, and C‐reactive protein (CRP) levels. Another

11.7  ­Health Benefits of Spent Coffee Ground

recent cohort study performed in 4455 Japanese men and 5942 Japanese women demonstrated lower serum C‐reactive protein concentrations in individuals with regular coffee intake. The alkaloid trigonelline is a niacin derivative that is also found in coffee beans. The antioxidant activity of trigonelline has not been evaluated in specific cell models, but in diabetic rats it reduces oxidative stress by upregulating anti­ oxidant enzyme activity with a decrease in lipid peroxidation. An in vitro study shows that trigonelline attenuates oxidative stress generated by copper ascorbate in mitochondria isolated from goat tissues. These tissues include heart, liver, brain, lung, and kidney. An in vitro study shows that trigonelline attenuates cop­ per ascorbate‐induced oxidative stress in mitochondria isolated from goat tis­ sues. These tissues include heart, liver, brain, lung, and kidney. Furthermore, the antioxidants kahweol and cafestol increased tripeptide glutathione (GSH) levels through γ‐glutamylcysteine synthetase induction, by affecting the rate‐limiting enzyme in GSH synthesis. Trigonelline shows therapeutic potential in several areas, including microbial diseases, diabetes, skeletal muscle stimulants, obesity, and cancer treatment [21]. Dietary fiber intake is important in childhood and may contribute to significant immediate and future health benefits: promote normal gastrointestinal function, especially laxation; prevent and treat childhood obesity; and reduce the risk of future chronic diseases, such as cancer [44]. In a meta‐analysis of 11 studies in which daily fecal weight was accurately measured in 26 groups of people (N = 206) with controlled diets of known fiber content, fiber intakes were significantly related to stool weight (r = 0.84). The weight of the feces varied enormously among subjects from different countries, from 72 to 470 g/day. The stool weight was inversely related to the risk of colon cancer in this study. There is a critical fecal weight of 160–200 g/day for adults, below which colon function becomes unpredictable and increases the risk of colon cancer [43]. Extensive epidemiological evidence supports the theory that dietary fiber can protect against large bowel cancer. Epidemiological studies that compare the inci­ dence of CRC or mortality rates between countries with estimates of national dietary fiber intake suggest that fiber in the diet may protect against colon cancer. When the results of 13 case–control studies of colorectal cannulas and dietary practices were pooled, the authors concluded that the results provided substantial evidence that the consumption of fiber‐rich foods is inversely related to the risks of colon and rectal cancers [43]. Products for skin protection, such as sunscreens and antioxidant compounds, should be highlighted in the healthy field since they could be able to prevent damages and harmful effects to the skin, including cancers caused by UV and by the intracellular imbalance between free radicals. A study shows that oil from

347

348

11  Health Benefits of Spent Coffee Grounds

SCG can present a synergistic effect when associated with a conventional syn­ thetic sunscreen (ethylhexyl methoxycinnamate), by increasing sun protection factor (SPF) to 20%. Its antioxidant activity and cytotoxicity were evaluated in vitro and the results showed good antioxidant activity and absence of cytotoxic effect for skin and liver cells. In conclusion, these results suggest that this oil is a promising natural product to be used in sunscreen formulations by improving SPF and, consequently, decreasing the concentration of synthetic chemical in such formulations [48, 49].

R ­ eferences 1 Murthy, P.S. and Madhava, N.M. (2012). Sustainable management of coffee industry by‐products and value addition‐A review. Resources Conservation and Recycling 66: 45–58. 2 The Food and Agriculture Organization Corporate Statistical Database (FAOSTAT (2019). http://www.fao.org/faostat/en/#data/QC (accessed 5 February 2019). 3 Janissen, B. and Huynh, T. (2018). Chemical composition and value‐adding applications of coffee industry by‐products: a review. Resources, Conservation and Recycling 128: 110–117. 4 Jiménez‐Zamora, A., Pastoriza, S., and Rufián‐Henares, J.A. (2015). Revalorization of coffee by‐products. Prebiotic, antimicrobial and antioxidant properties. LWT Food Science and Technology 61 (1): 12–18. 5 Iriondo‐DeHond, A., Aparicio, G.N., Fernandez‐Gomez, B. et al. (2019). Validation of coffee by‐products as novel food ingredients. Innovative Food Science and Emerging Technolgies 51: 194–204. 6 Esquivel, P. and Jiménez, V. (2012). Functional properties of coffee and coffee by‐products. Food Research International 46 (2): 488–495. 7 Campos‐Vega, R., Loarca‐Piña, G., Vergara‐Castañeda, H.A. et al. (2015). Spent coffee grounds: a review on current research and future prospects. Trends in Food Science and Technology 45 (1): 24–36. 8 Vázquez‐Sánchez, K., Martinez‐Saez, N., Rebollo‐Hernanz, M. et al. (2018). In vitro health promoting properties of antioxidant dietary fiber extracted from spent coffee (Coffee arabica L.) grounds. Food chemistry 261: 253–259. 9 Martinez‐Saez, N. and del Castillo, M.D. (2019). Development of sustainable novel foods and beverages based on coffee by‐products for chronic diseases. Reference Module in Food Science, Encyclopedia of Food Security and Sustainability 1: 307–315. 10 Jenkins, R.W., Stageman, N.E., Fortune, C.M. et al. (2014). Effect of the type of bean, processing, and geographical location on the biodiesel produced from waste coffee grounds. Energy and Fuels 28 (2): 1166–1174.

 ­Reference

1 1 Ballesteros, L.F., Teixeira, J.A., and Mussatto, S.I. (2014). Chemical, functional, and structural properties of spent coffee grounds and coffee silverskin. Food and Bioprocess Technology 7 (12): 3493–3503. 12 Xu, H., Xie, L., and Hakkarainen, M. (2017). Coffee‐ground‐derived quantum dots for aqueous processable nanoporous graphene membranes. ACS Sustainable Chemistry & Engineering 5: 5360–5367. 13 Somnuk, K., Eawlex, P., and Prateepchaikul, G. (2017). Optimization of coffee oil extraction from spent coffee grounds using four solvents and prototype‐scale extraction using circulation process. Agriculture and Natural Resources Elsevier Ltd 51 (3): 181–189. https://doi.org/10.1016/j.anres.2017.01.003. 14 Campos‐Vega, R., Vázquez‐Sánchez, K., López‐Barrera, D. et al. (2015). Simulated gastrointestinal digestion and in vitro colonic fermentation of spent coffee (Coffea arabica L.): bioaccessibility and intestinal permeability. Food Research International 77 (2): 156–161. 15 de Melo, M.M., Barbosa, H.M., Passos, C.P., and Silva, C.M. (2014). Supercritical fluid extraction of spent coffee grounds: measurement of extraction curves, oil characterization and economic analysis. The Journal of Supercritical Fluids 86: 150–159. 16 Wei, F., Furihata, K., Koda, M. et al. (2012). Roasting process of coffee beans as studied by nuclear magnetic resonance: time course of changes in composition. Journal of Agricultural and Food Chemistry 60 (4): 1005–1012. 17 García‐Gutiérrez, N., Maldonado‐Celis, M.E., Rojas‐López, M. et al. (2017). The fermented non‐digestible fraction of spent coffee grounds induces apoptosis in human colon cancer cells (SW480). Journal of Functional Foods 30: 237–246. 18 Hernández‐Arriaga, A.M., Oomah, D.B., and Campos‐Vega, R. (2017). Microbiota source impact in vitro metabolite colonic production and anti‐proliferative effect of spent coffee grounds on human colon cancer cells (HT‐29). Food Research International 97: 191–198. 19 López‐Barrera, D.M., Vázquez‐Sánchez, K., Loarca‐Piña, G.F. et al. (2016). Spent coffee grounds, an innovative source of colonic fermentable compounds, inhibit inflammatory mediators in vitro. Food Chemistry 212: 282–290. 20 Kovalcik, A., Obruca, S., and Marova, I. (2018). Valorization of spent coffee grounds: a review. Food and Bioproducts Processing 110: 104–119. 21 Dorsey, B.M. and Jones, M.A. (2017). Healthy components of coffee processing by‐products. In: Handbook of Coffee Processing By‐Products (ed. C.M. Galanakis), 27–62. Ilinois: Academic Press. 22 Menon, V. and Rao, M. (2012). Recent Trends in Valorization of Lignocellulose to Biofuel. In: Microorganisms in Sustainable Agriculture and Biotechnology (eds. T. Satyanarayana, A. Prakash and B.N. Johri), 381–410. Dordrecht: Springer. 23 Stylianou, M.A., Agapiou, A., Omirou, M., et al. (2017) Potential environmental applications of spent coffee grounds. Proceedings of the 5th International

349

350

11  Health Benefits of Spent Coffee Grounds

24 25 26

27

28

29

30

31

32

33

34

35

Conference on Sustainable Solid Waste Management, 21–24 June 2017, Athens, Greece. http://uest.ntua.gr/athens2017/proceedings/presentations/Stylianou_ Athens_SCG_Presentation_21062017.pdf (accessed 20 February 2019). Pujol, D., Liu, C., Gominho, J. et al. (2013). The chemical composition of exhausted coffee waste. Industrial Crops and Products 50: 423–429. Givens, D.I. and Barber, W.P. (1986). In vivo evaluation of spent coffee grounds as a ruminant feed. Agricultural Wastes 18: 69–72. Rahimnejad, S., Choi, J., and Lee, S.‐M. (2015). Evaluation of coffee ground as a feedstuff in practical diets for olive flounder Paralichthys olivaceus. Fisheries and Aquatic Sciences 18 (3): 257–264. Choi, Y., Rim, J.‐S., Na, Y., and Lee, S.R. (2018). Effects of dietary fermented spent coffee ground on nutrient digestibility and nitrogen utilization in sheep. Asian‐ Australasian Journal of Animal Sciences 31 (3): 363–368. Murthy, P.S. and Madhava, N.M. (2012). Recovery of phenolic antioxidants and functional compounds from coffee industry by‐products. Food and Bioprocess Technology 5 (3): 897–903. Trongchuen, K., Ounkaew, A., Kasemsiri, P. et al. (2018). Bioactive starch foam composite enriched with natural antioxidants from spent coffee ground and essential oil. Strach 70 (7–8): 1700238. https://doi.org/10.1002/star.201700238. Campos‐Vega, R., Reynoso‐Camacho, R., Ramos‐Gómez, M. et al. (2014). Natural foods as biosystems to face noncommunicable chronic diseases: an overview. In: Biosystems engineering: Biofactories for food production in the century XXI (eds. R. Guevara‐González and I. Torres‐Pacheco), 289–318. Heidelberg New York Dordrecht London: Springer Cham. Goya, L., Delgado‐Andrade, C., Rufián‐Henares, J.A. et al. (2007). Effect of coffee melanoidin on human hepatoma HepG2 cells. Protection against oxidative stress induced by tert‐butylhydroperoxide, Molecular Nutrition & Food Research 51 (5): 536–545. Fuentes‐Barría, H., Muñoz, D., Aguilera, R., and González, C. (2018). Influence of the bioactives compounds of beetroot (Beta vulgaris L.) on the cardioprotective effect: a narrative review. Revista Chilena de Nutrición 45 (2): 178–182. Ormaza, A., Díaz, F., and Rojano, B. (2018). Efecto del añejamiento del café (Coffea arabica L. var. Castillo) sobre la composición de fenoles totales, flavonoides, ácido clorogénico y la actividad antioxidante. Información Tencológica 29 (3): 187–196. Al‐Dhabi, N.A., Ponmurugan, K., and Jeganathan, P.M. (2017). Development and validation of ultrasound‐assisted solid‐liquid extraction of phenolic compounds from waste spent coffee grounds. Ultrasonics Sonochemistry 34: 206–213. Bray, G.A., Kim, K.K., Wilding, J.P.H., and World Obesity Federation (2017). Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Obesity Reviews 18 (7): 715–723.

 ­Reference

3 6 Furukawa, S., Fujita, T., Shimabukuro, M. et al. (2017). Increased oxidative stress in obesity and its impact on metabolic syndrome. The Journal of Clinical Investigation 114 (12): 1752–1761. 37 Chiyanzu, I., Brienzo, M., García‐Aparicio, M.P. et al. (2014). Application of endo‐β‐1, 4, d‐mannanase and cellulase for the release of mannooligosaccharides from steam‐pretreated spent coffee ground. Applied Biochemistry and Biotechnology 172 (7): 3538–3557. 38 St‐Onge, M.P. (2014). Coffee consumption and body weight regulation. In: Coffee in Healt and Disease Prevention (ed. V. Preedy), 499–506. London: Academic Press. 39 Brazinha, C., Cadima, M., and Crespo, J.G. (2015). Valorisation of spent coffee through membrane processing. Journal of Food Engineering 149: 123–130. 40 Pimentel, G.D., Micheletti, T.O., and Nehlig, A. (2014). Coffe intake and obesity. In: Nutrition in the Prevention and Treatment of Abdominal Obesity, first edn (ed. R.R. Watson), 245–259. London: Academic Press. 41 Perumareddi, P. (2018). Prevention of hypertension related to cardiovascular disease. Primary Care: Clinics in Office Practice 46 (1): 27–39. 42 Mussato, S.I. (2014). Generating biomedical polyphenolic compounds from spent coffee or silverskin. In: Coffee in Healt and Disease Prevention (ed. V. Preedy), 93–106. London: Academic Press. 43 Slavin, J.L. (2008). Position of the American Dietetic Association: health implications of dietary fiber. Journal of American Dietetic Association 108 (10): 1716–1731. 44 Anderson, J.W., Baird, P., Davis, R.H. Jr. et al. (2009). Health benefits of dietary fiber. Nutrition Reviews 67 (4): 188–205. 45 Turnbull, D., Rodricks, J.V., Mariano, G.F. et al. (2017). Caffeine and cardiovascular health. Regulatory Toxicology and Pharmacology 89: 165–185. 46 Monente, C., Ludwig, I.A., Stalmach, A. et al. (2015). In vitro studies on the stability in the proximal gastrointestinal tract and bioaccessibility in Caco‐2 cells of chlorogenic acids from spent coffee grounds. International journal of food sciences and nutrition 66 (6): 657–664. 47 Panusa, A., Zuorro, A., Lavecchia, R. et al. (2013). Recovery of natural antioxidants from spent coffee grounds. Journal of Agricultural and Food Chemistry 61: 4162–4168. 48 Marto, J., Gouveia, L.F., and Chiari, B.G. (2016). The green generation of sunscreens: using coffee industrial sub‐products. Industrial Crops and Products 80: 93–100. 49 Chiari, B.G., Trovatti, E., Pecoraro, É. et al. (2014). Synergistic effect of green coffee oil and synthetic sunscreen for health care application. Industrial Crops and Products 52: 389–393. 50 Bekedam, E.K., Loots, M.J., Schols, H.A. et al. (2008). Roasting effects on formation mechanisms of coffee brew melanoidins. Journal Agricultural Food Chemistry 56: 7138–7145.

351

353

12 Health Benefits of Silverskin Amaia Iriondo-DeHond, Teresa Herrera, and María Dolores Del Castillo Department of Bioactivity and Food Analysis, Instituto de Investigación en Ciencias de la Alimentación (CIAL) (CSIC-UAM), Campus de la Universidad Autónoma de Madrid, Madrid, Spain

12.1 ­Introduction Coffee silverskin (CS) is the thin tegument that covers the two coffee seeds and it is the only by‐product generated during green bean roasting (Figure 12.1). It only represents about 4.2% (w/w) of the coffee cherry, but large amounts of CS are produced worldwide in coffee roasting countries [1]. The chemical composition of CS (Table 12.1) [2] shows that dietary fiber (up to 55%) is the main component including insoluble (~45%) and soluble (~10%) fiber [5, 6]. CS has high protein (18%) and low fat (2%) contents. Therefore, CS can be considered a “source of proteins low in fat” since it contains over 12% proteins and less than 3% fat, respectively (Regulation (EU) No. 1047/2012). CS is also a source of polyphenols, particularly chlorogenic acid (CGA) (588.9 mg/100 g) with 5‐O‐, 3‐O‐, and 4‐O‐caffeoylquinic acids being the most relevant (Table  12.1) [7]. In addition, CS also contains caffeine (1%) and melanoidins (5%); the latter formed during the roasting process [3, 8]. Various technologies have been described to recover polyphenolic and antioxidant compounds from CS by different extraction methods and conditions [9]. Ethanol and water are the most common solvents used for solid–liquid extraction of total phenolics from CS; the composition and antioxidant capacity of obtained extracts varies with different extraction conditions (Table  12.2). Freeze‐dried Robusta CS from Indonesia had a particularly high total phenolic content (TPC) (163 mg GAE/g CS) with less than half (40%) the antioxidant capacity of ascorbic acid (350 vs. 141 ppm IC50) [10]. Pulsed electric field (PEF)‐assisted extraction, Food Wastes and By-products: Nutraceutical and Health Potential, First Edition. Edited by Rocio Campos-Vega, B. Dave Oomah, and Haydé Azeneth Vergara-Castañeda. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

354

12  Health Benefits of Silverskin Silverskin Coffee processing

Coffee cherry

Coffee roasting

Green beans

Coffee silverskin

Figure 12.1  Coffee silverskin location in the coffee cherry and its generation. Table 12.1  Chemical composition (%) of coffee silverskin (CS). Characteristics

Coffee silverskin (CS)

Moisture (%)

4.8

Ash (%)

8.3

Fat (%)

2.4

SFA (%)

64.8

MUFA (%)

7.1

PUFA (%)

28.1

Protein (%)

18.8

Carbohydrates (%)

5.8

Total fiber (%)

56.4

Insoluble fiber (%)

49.1

Soluble fiber (%) Caffeine (%)

7.3 1.3

Total chlorogenic acid (mg/100 g)

588.9

3‐CQA (mg/100 g)

147.8

4‐CQA (mg/100 g)

84.9

5‐CQA (mg/100 g)

198.9

Vitamin E (%)

0.004

5‐Hydroxymethylfurfural (%)

0.006

Melanoidins (%)

4.5

3‐CQA, 3‐caffeoylquinic acid; 4‐CQA, 4‐caffeoylquinic acid; 5‐CQA, 5‐caffeoylquinic acid; SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids. Source: from [2–4].

a nonthermal environmentally friendly technology, improved polyphenolics yield (19%) from CS compared to unassisted extraction with TPC values similar to solid–liquid extraction [11]. However, ultrasound (UAE, 40 kHz frequency, 300 W power) and microwave (MAE, 280 W power)‐assisted extraction of aqueous

Table 12.2  Extraction conditions of coffee silverskin antioxidants recovery. Antioxidants

Extraction conditions

Botanical species

TPC (mg GAE/g)

Flavonoids (mg CE/g) a

Overall antioxidant capacity

References

ETOH (50%, 1:50 g/mL, 40 °C, 60 min)

40/60 Arabica/ Robusta

15.1

4.2

16.3 mg TE/g (DPPH assay) 89.6 mg FSE/g (FRAP assay)

Costa et al. [67]

ETOH (50%, 1:50 g/mL, 40 °C, 60 min)

Robusta

5.2–20.3

2.1–4.8a

24.1–40.6 inhibition % (DPPH assay) 4.4–20.5 mM FSE (FRAP assay)

Bessada et al. [53]

ETOH (50% 1:10 g/mL, 40 °C, 60 min)

Robusta

162.9

6.3

IC50 350 ppm (DPPH assay)

Tan et al. [10]

ETOH (60%, 1:35 g/mL, 60 °C, 30 min)

Mixture Arabica/ Robusta

13

1.7b

18.2 μmol TE/g (DPPH assay) 0.8 mmol FSE (FRAP assay)

Ballesteros et al. [6]

ETOH (60%, 1:35 g/mL, 80 °C, 45 min)

Mixture Arabica/ Robusta

10

n.r.

39 μmol TE/g (DPPH assay)

Guglielmetti et al. [12]

ETOH (39%, 1:140 g/mL, 119 min, PEF Arabica 1.74 kV/cm)

9.3–12.0

2.9–3.7

47.7–66.1 μM TE/g (DPPH assay)

Barbosa‐Pereira et al. [11]

ETOH (39%, 1:140 g/mL, 119 min, PEF Robusta 1.74 kV/cm)

9.9–12.9

3.1–4.1

54.6–71.3 μM TE/g (DPPH assay)

Barbosa‐Pereira et al. [11]

H2O (1:20 g/mL, 200 °C, 20 min)

Arabica

46.3c

n.r.

36.7 mg CAE/g (ABTS assay)

del Castillo et al. [14]

H2O (1:20 g/mL, 100 °C, 10 min)

Arabica

44.8c

3.4

138.7 (mg CAE/g) (ABTS assay)

Iriondo‐DeHond et al. [68]

H2O (1:20 g/mL, 100 °C, 10 min)

Robusta

56.5c

6.3

169.5 (mg CAE/g) (ABTS assay)

Iriondo‐DeHond et al. [68] (Continued)

0004467239.INDD 355

06-11-2019 18:22:38

Table 12.2  (Continued) Antioxidants TPC (mg GAE/g)

Flavonoids (mg CE/g)

Overall antioxidant capacity

References

Mixture Arabica/ Robusta

123

n.r.

379 μmol TE/g (DPPH assay)

Narita and Inouye [13]

H2O (1:50 g/mL, 60 °C, 30 min)

Arabica

7.8

n.r.

6.7 mg TE/g (DPPH assay)

Panusa et al. [15]

H2O (1:50 g/mL, 60 °C, 30 min)

Robusta

12.8

n.r.

9.2 mg TE/g (DPPH assay)

Panusa et al. [15]

H2O (1:30 g/mL, 120 °C, 20 min)

n.r.

22.2

2.5

13.9 mg TE/g (DPPH assay) 99.8 mg FSE/g (FRAP assay)

Procentese et al. [69]

H2O (1:20 g/mL, 120 °C, 20 min)

n.r.

19.2

2.8

64 (% inhibition) (DPPH assay)

Conde and Mussatto [70]

Extraction conditions

Botanical species

H2O (1:50 g/mL, 270 °C, 10 min)

n.r, not reported; TPC, total phenolics content; DPPH, 2,2 diphenyl‐1‐picrylhydrazyl radical; FRAP, ferric‐reducing antioxidant power; GAE, gallic acid equivalents; CAE, chlorogenic acid equivalents; CE, catechin equivalents; FSE, ferrous sulfate equivalents. a  Values in mg of epicatechin equivalents (ECE)/g; b  Value in mg of quercetin equivalent (QE)/g. c  Values in mg of chlorogenic acid equivalents (CAE)/g.

0004467239.INDD 356

06-11-2019 18:22:38

12.1 ­Introductio

e­ thanol resulted in similar or higher CS phenolics than conventional solvent extraction [12]. Hot water extracts show similar or often more CS phenolics than aqueous ethanol extractions with the highest phenolics extracted with subcritical water at 270 °C [13, 14] (Table 12.2). Generally, Robusta CS generally has higher total phenolics and antioxidant capacity than Arabica CS (Table  12.3). For instance, the TPC of aqueous CS extract (CSE) from Robusta CS was about 1.5 times higher than that of Arabica CS (12.8 vs. 7.8 mg GAE/g) [15]. Aqueous extraction processes are green processes that meet the challenges to protect both the environment and consumers. Table 12.3 summarizes the chemical composition of the aqueous CSE patented by our research group. It is rich in total dietary fiber (28–36%), which includes about 4–9% insoluble dietary fiber and 24–26% soluble dietary fiber. CSE is a good source of polyphenols, particularly CGA (1–6%), caffeine (3%), and melanoidins (17–23%) [7, 16]. The presence of CGA and melanoidins may contribute to the antioxidant properties of CSE [7, 14, 17]. The chemical composition of CSE suggests that it may be a good source of bioactive compounds with putative effects on human health [14, 17]. Since more than 95% of chronic diseases are caused by food choices and lack of physical exercise, many plant extracts and natural compounds are emerging as functional candidates to reduce the risk of noncommunicable chronic diseases. Table 12.3  Chemical composition of coffee silverskin extracts. Compounds

Proteins (g) Carbohydrates (g)

ACSE (per 100 g)

RCSE (per 100 g)

5.36

0.99

5.44

13.43

Total dietary fiber (g)

28.69

36.21

Soluble dietary fiber (g)

24.01

26.80

4.67

9.41

Insoluble dietary fiber (g) Caffeine (g)

3.02

3.39

17.26

23.94

CGAs (g)

1.12

6.85

Total phenolic content (g)

3.10

3.54

Melanoidins (g)

ORAC (mmol TEAC)

119.4

151.3

DPPH (mmol TEAC)

21.9

23.1

ABTS (mmol TEAC)

8.5

22.5

FRAP (mmol TEAC)

82.9

64.0

ACSE, Arabica coffee silverskin extract; RCSE, Robusta coffee silverskin extract; CGAs, chlorogenic acids; TEAC, Trolox equivalent antioxidant capacity. Source: based on [7].

357

358

12  Health Benefits of Silverskin

The recycling of food wastes into health‐promoting products is of great interest worldwide. In particular, the coffee industry is responsible for generating large amounts of wastes, and coffee by‐products may be sustainable sources of bioactive compounds with health‐promoting and therapeutic properties. This chapter focuses on the potential of a coffee by‐product, CS, as a functional ingredient for preventing metabolic disorders and improving gastrointestinal and skin health. The data presented here support the valorization of CS into a functional food ingredient as a good strategy to achieve a sustainable health.

12.2 ­Improvement of Gastrointestinal Health Dietary fiber is one of the main nutritional factors contributing to human well‐ being [18]. The European Food Safety Authority (EFSA) defines dietary fiber as non‐digestible carbohydrates, including non‐starch polysaccharides, resistant starch and oligosaccharides, and lignin [19]. Dietary fiber presents two main forms depending on its solubility in water: soluble and insoluble fiber. Dietary fiber has important physiological effects on glucose and lipid metabolism and mineral bioavailability. Today, dietary fiber is known to protect against certain gastrointestinal diseases, constipation, hemorrhoids, colon cancer, gastroesophageal reflux disease, duodenal ulcer, diverticulitis, obesity, diabetes, stroke, hypertension, and cardiovascular diseases [20]. The high dietary fiber content (up to 55%) of CS, predominantly insoluble fiber, can potentially benefit the intestine and gut microbiota [2, 5, 6]. The prebiotic properties of CS described previously demonstrate that CS preferentially supports the bifidobacterial growth in vitro, suggesting that its consumption may have some prebiotic effects [3]. CS also increased the number of healthy bacteria such as Lactobacillus spp. and Bifidobacterium spp. without affecting the levels of Bacteroides spp. and Clostridium spp. [5]. Therefore, CS can be a suitable ingredient in formulating foods with prebiotic activity. Fiber‐enriched foods have been developed in the past few years to increase dietary fiber consumption to reduce the risk of chronic diseases (Figure 12.2). CS has been employed as dietary fiber to formulate breads; CS as a food ingredient reduces caloric density and increases the dietary fiber content of bread [21]. CS has also been used as coloring and as dietary fiber source, to achieve a healthier, nutritious, and high sensorial quality biscuit. CS improved moisture, texture, thickness, and color of the novel biscuits [22]. CS has also been used in another bakery product, cakes, that have been formulated with up to 30% of water‐treated CS as a flour substitute [8, 23]. Water treatment of CS enhanced moisture content and textural and sensory attributes of cakes. Cakes with water‐treated CS presented similar physical and sensory characteristics to the control cake [8]. The

12.3  ­Prevention of Metabolic Disorder Coffee silverskin

Bread

High dietary fiber

Biscuits

Cakes

Prebiotic properties

Antioxidant capacity

Improved gastrointestinal health

Figure 12.2  Application of coffee silverskin (CS) as a food ingredient in different food matrixes to improve gastrointestinal health.

combined use of stevia and CS has also been used to achieve healthier, nutritious, and good quality biscuits [22]. The complete replacement of sucrose by stevia affected the moisture content of the biscuits, but this was improved by the addition of CS. The nutritional value and the appearance of the biscuits also improved by the addition of CS [22].

12.3 ­Prevention of Metabolic Disorders Metabolic disorders have reached epidemic proportions in developed countries. According to World Health Organization (WHO) in 2016, 39% of adults aged 18 years and over were overweight [24]. Overall, about 13% of the world’s adult population were obese in 2016. Disruption of normal metabolic processes results in energy and redox imbalance, producing many pathophysiological conditions in the body, which are known as metabolic disorders. These processes include elevated body weight and obesity, insulin resistance, hypertension and dyslipidemia, leptin resistance, reduced adiponectin, defective insulin secretion, and glucose intolerance. An individual must have at least three of the risk factors to be diagnosed with metabolic syndrome [25]. These risk factors lead to cellular dysfunction and redox imbalance that contribute to the progression of the pro‐oxidative environment leading to damaged biomolecules. A clear correlation between

359

360

12  Health Benefits of Silverskin

­ xidative stress and metabolic disorders has emerged, which can be helpful in the o identification of novel biomarkers, molecular targets, and effective drug development for prevention and therapy of these diseases.

12.3.1  Obesity and Dyslipemia Overweight and obesity are defined as abnormal or excessive fat accumulation in  subcutaneous tissues and in the abdominal cavity that may impair health. Reducing weight (10% at least), by increased exercise and improved dietary habits, with a reduction in total calorie and saturated fatty acid intake, is one of the strategies for treatment of these diseases. Medical therapy can be initiated if lifestyle changes are insufficient. As a consequence, it is necessary to search for natural sources and develop novel foods, drugs, or supplements to prevent and treat obesity. Plant extracts have attracted much attention as potential therapeutic agents in the prevention and treatment of obesity due to their multiple targets and low/ limited toxic side effects [26]. Several epidemiological investigations associate coffee consumption with weight control and obesity. Healthy effects associated with food largely depend on the bioaccessibility and bioavailability of their bioactive components in the organism. In this regard, CS emerges as a natural source of several bioactive compounds, such as CGA, caffeine, and melanoidins (Table 12.1). The anti‐obesity effect (reduction of the body fat mass and body fat percentage) of coffee may be attributed to caffeine [27], CGAs [28] and melanoidins that are also present in CS. A significant dose‐ dependent effect on reducing body fat accumulation was found for pure CGA (3.54 mg/L) and caffeine (4.85 mg/L), achieving approximately 30% reduction of lipid deposits in Caenorhabditis elegans used as an in vivo animal model [17]. Dyslipemia is a multifactorial disorder observed in obesity that includes hepatic overproduction of very low density lipoproteins, decreased circulating triglycerides, lipolysis, and impaired peripheral free fatty acid (FFA) trapping, increased FFA fluxes from adipocytes to the liver and other tissues and the formation of small low density lipoprotein (LDL). In an in vivo study, an aqueous CSE reduced total cholesterol and triglycerides plasma levels in rats after 45‐ day treatment with CSE (2.2 and 0.8 mg caffeine and CGA per kilogram of body weight). Furthermore, CSE (36 mg/mL) reduced (41.73%) pancreatic lipase activity in vitro [29]. This could explain the mechanism of action of the observed reduction of total cholesterol and triglycerides since pancreatic lipase is a key enzyme in fat digestion. Together, these results support the lyporegulatory character of CS through pancreatic lipase inhibition and therefore its preventive and therapeutic effect in obesity (Figure 12.3). Different mechanisms have been proposed relative to lipid metabolism regulation due to the presence of bioactive compounds such as caffeine, CGA, and melanoidins in CS. These compounds can modulate cell signaling, reduce lipid accumulation and size of adipocytes [30], decrease total

12.3  ­Prevention of Metabolic Disorder

COOH TAG

Lipase

FA

COOH COOH

COOH COOH

FA

MAG

COOH

Anti-obesity effect Phytochemical bioactive compounds

Antidiabetic effect α-Glucosidase Starch Dissacharides

Figure 12.3  Anti-obesity and antidiabetic properties of coffee silverskin (CS) by the inhibition of key enzymes of lipid and carbohydrate metabolism.

plasma cholesterol and triglycerides [22], inhibit pancreatic lipase [31, 32], regulate hepatic lipid metabolism‐related enzymes [33], and suppress genes involved in adipogenesis and inflammation in visceral adipose tissue [34]. In addition, coffee melanoidins, which may also be present in CS, can protect against non‐alcoholic fatty liver disease by reducing hepatic fat accumulation in a rat model [35]. Anti‐obesity properties of CS have also been studied in novel antioxidant beverages based on CS from Arabica and Robusta species to determine their inhibitory effect on in vivo fat accumulation using C. elegans as an animal model [17]. CGA and coffee melanoidins may play a key role in reducing and controlling body weight and may, therefore, be of interest in treating and reducing the risk of obesity [28, 35]. Both beverages made from Arabica and Robusta CSE (100 μg/mL) reduced body fat by 21 and 24%, respectively, possibly due to the presence of these compounds at physiologically active doses [17]. Furthermore, Robusta CSE beverage and a commercial dietary supplement that is made from Robusta decaffeinated green coffee extract showed a similar effect on body fat reduction. Another strategy to reduce excessive fat intake is the development of novel products with lower fat content and improved nutritional values. In this regard, CS has been used as a fat replacer in cake formulations to increase fiber content and add antioxidant properties to the food matrix. Results obtained from this research indicated that CS may be an alternative fiber source for replacing oil in cake formulations [23]. CS has also been employed as dietary fiber for the formulation of other bakery products, such as bread [21]. Results showed the feasibility of using alkaline hydrogen peroxide CS as a food ingredient to reduce caloric density and increase the dietary fiber content of bread. Therefore, CS may be a natural and sustainable alternative to dietary supplements for the prevention of

361

362

12  Health Benefits of Silverskin

­ verweight and obesity by the inhibition of key enzymes of lipid metabolism and o the reduction of caloric density in food products [17, 22].

12.3.2  Diabetes Several studies have shown that oxidative stress is a key element in the development and progression of diabetes and its associated complications [36]. Diabetes mellitus is a chronic endocrine and metabolic disorder, which is underlined by insulin deficiency or insulin insensitivity or both and characterized by hyperglycemia. The development of type 2 diabetes (T2D) is usually associated with a combination of insulin resistance and beta cell failure leading to high blood glucose levels. Generally, the effects of hyperglycemia are classified as macrovascular complications (coronary artery disease, peripheral arterial disease, and stroke) and microvascular complications (diabetic nephropathy, neuropathy, and retinopathy). Not all but most patients with T2D are overweight or obese. In fact, the excess of weight itself causes some degree of insulin resistance [37, 38]. The bioactive compounds present in CS (CGA, caffeine, and melanoidins) are metabolized and play a role with vital organs involved in the pathogenesis of diabetes and its complications. Previous studies carried out by our research group described that caffeine (present in CSE) was metabolized and their metabolites protected the pancreas against oxidative stress in rats suffering streptozotocin (STZ)‐induced diabetes [16]. Results suggest that these metabolites are more effective than the parental molecule in the prevention of oxidative stress during diabetes. Caffeine can reduce glucose levels and insulin sensitivity and improve pancreas functionality of diabetic rats [39, 40]. Other authors have also observed a protective effect of caffeine in pancreatic β‐cells [41, 42]. In this sense, the components of CSE have a positive effect on pancreatic health, thereby reducing the risk of this disease. Several studies have described the effects of CS on diabetes biomarkers. This by‐product obtained from coffee roasting has been shown to produce increased glucose tolerance [43], enhance insulin sensitivity and secretion [43, 44], inhibit enzymatic α‐glucosidase activity (Figure  12.3) [44], inhibit advanced glycation end product (AGE) formation through the interaction of CGA and its derivatives with protein backbone [32, 45], and protect against oxidative stress [46]. Moreover, CSE may protect pancreatic tissue in vitro against oxidative stress induced by the commonly used diabetogenic agent STZ [47]. The antidiabetic mechanism of action of CSE in vivo should be further investigated. All these effects have an impact on diabetes development and, as a consequence, CSE may be useful in both the prevention and treatment of diabetes. Other coffee constituents relevant for diabetes are melatonin, melanoidins, tannic acid, trigonelline, and isoflavones, all of which may also be present in CS. Melatonin, a tryptophan derivative, has been detected in CSE (3.4 mg/g dry matter) [16].

12.4 ­Improvement of Skin Healt

Experimental evidence indicated that melatonin has the potential to reduce the risk of T2D by protecting β‐cells against oxidative stress, as it neutralizes the production of reactive species and normalizes the redox state in the cell [39]. Melatonin, CGA, and other coffee antioxidants (CGA and its metabolites, caffeine metabolites, and melanoidins, among others) may exert synergic effects protecting the pancreas against oxidative stress and the development of diabetes. However, further research should be carried out in order to confirm this hypothesis. Melanoidins from CSE have carbonyl trapping capacity and inhibit fluorescent AGEs formation [22]. Hence, these compounds could be used as inhibitors of AGE‐related diseases. Furthermore, melanoidins and CGA may contribute to synergistic inhibitory effect on AGE formation. Tannins have also been proposed as antidiabetic agents due to their hypoglycemic and antioxidant activities observed in vitro [48] and in vivo [49]. Trigonelline has health‐promoting properties related to diabetes such as hypoglycemic, hypocholesterolemic, and hypotriglyceridemic effects. Previous studies suggest that trigonelline may play a key role in improving insulin content in plasma and in pancreas, as well as in insulin sensitivity index in diabetic rats [50]. In addition, trigonelline regulates glucose and lipid metabolism through the inhibition of key enzymes [51]. Further research should be conducted to elucidate the contribution of these individual compounds to the antidiabetic effect observed for CS.

12.4 ­Improvement of Skin Health The skin is the largest organ on the human body and its main role is to act as a chemical and physical barrier to protect the body against harmful external environmental agents such as pathogens, ultraviolet (UV) radiation, chemicals, temperature changes, and dehydration [52]. Aging is an inevitable, universal phenomenon that consists of an accumulation of changes in cells, tissues, and organs over time, which leads to a progressive loss of structure and function [53]. Oxidative stress is the major cause of accelerated skin aging and diseases, which is defined as the imbalance between reactive oxygen species (ROS) and antioxidants [54]. Skin aging is a complex biological process caused by intrinsic and extrinsic factors. Intrinsic factors include cellular metabolism, genetics, hormones, and the passage of time, which lead to an unavoidable increased fragility and loss of skin elasticity. In contrast, extrinsic aging factors include repetitive exposure to harmful agents, especially UV light (photo‐ aging), inappropriate diet, pollution, chemicals, and toxins and can be avoided [52]. UV exposure is the major causative factor for age‐related changes including inflammation, degenerative aging, extracellular matrix degeneration and cancer [52]. UV radiation overexposure causes generation of ROS, leading to an oxidative stress status. This prooxidative situation causes lipid and protein oxidation, loss of

363

364

12  Health Benefits of Silverskin

mitochondrial potential, and DNA damage. In addition, ROS increase can activate inflammatory responses and upregulate matrix metalloproteinase (MMP) production and activity, resulting in collagen breakdown [53]. The connection between nutrition, skin, and aging has been an increasing research area for scientists and physicians worldwide. It is accepted that nutritional status concerning both macro and micronutrients is important for skin health and appearance. Nutricosmetics are nutritional supplements that support structure, function, and skin health. Supplementation with vitamins, minerals, and phytonutrients offers antioxidant protection, anti‐inflammatory effects, photoprotection properties, enhanced collagen synthesis, and skin cell turnover optimization, as well as skin hydration promotion. Therefore, a balanced diet associated with oral supplementation of nutraceuticals could represent an approach for improving skin health [55]. Most of the bioactive food compounds responsible for the positive effects on health are predominantly derived from plants. Cosmetic industry has been searching for new active ingredients, due to the consumers’ demand for more natural and environmentally friendly products obtained by sustainable resources that improve healthy skin appearance [53]. CS is a potential candidate to replace synthetic chemicals as active ingredients in cosmetic formulations due to its high antioxidant potential, phenolic compounds, and melanoidin and caffeine content [53]. The interest of using aqueous CSE in cosmetics was proposed for the first time by del Castillo et  al., in a patent application filed in 2011, which became public in 2013 (WO/2013/004873). In addition, in 2017 CS has been recognized as a cosmetic ingredient as “Water (and) Coffee Arabica/Robusta Chaff Extract” by the International Cosmetic Ingredient Nomenclature Committee (INCI). Two promising compounds for anti‐wrinkle products are present in CS: caffeine and CGA. CGA has been described as an antiaging compound in C. elegans. It has been demonstrated that CGAs, caffeine, melanoidins, and other bioactive compounds all together in CS may act synergistically to protect from UV‐induced accelerated aging on C. elegans [54]. CSE (1 mg/mL) significantly increased longevity in nematodes compared to those cultured on a standard diet. The increased longevity was similar to that observed in nematodes fed on CGA or vitamin C (0.1 μg/mL). In this study, accelerated aging was also induced in human keratinocytes (HaCaT cell line) as a skin model by tert‐butyl hydroperoxide (t‐BOOH). CSE at 1 mg/mL increased resistance to skin cells exposed to t‐BOOH‐induced oxidative stress. The antiaging properties of CS observed in this study are due to its antioxidant character derived from phenolics (presumably caffeic acid), among other bioactive compounds present in the botanical material [54]. Therefore, CS extracts have the potential to be used as an antiaging ingredient in skin cosmetic products to reduce the production of intracellular ROS in keratinocytes and improving skin health.

12.4 ­Improvement of Skin Healt

Oxidative stress can also lead to DNA lesions such as DNA strand breaks and oxidized bases [56]. Considering the high antioxidant power of CS, this extract could protect cells from DNA damage when induced by an oxidative agent. Benzo(a)pyrene (B(a)P) is a carcinogenic polycyclic aromatic hydrocarbon (PAH) found in air, water, soils, and thermally processed foods and cigarette smoke that induces ROS production in cells during the metabolism of this food mutagen, which leads to DNA damage [57]. The protective effect of CS and CGA were evaluated against B(a)P‐induced DNA damage (strand breaks and oxidized purines/pyrimidines) in HepG2 cells. DNA strand breaks decreased when cells were pretreated with CS and CGA [58]. Several authors have confirmed the protective effect of roasted coffee consumption on DNA integrity in humans [59, 60]. The reduction of spontaneous DNA strand breaks may be attributed to the presence of antioxidants with chemo preventive properties (such as CGAs and roast‐associated constituents) [59]. Considering that CS partly retains polyphenolic compounds that are normal constituents of coffee beans, such as CGA, it is likely that this effect ascribed for coffee brews is also maintained in CS. These results indicate that CS protects human cells from DNA strand breaks and B(a) P‐induced oxidative DNA damage and that free CGA or bound to other chemical structures presumably contributes to the observed chemo protective effect of CSE [58]. Another cause of skin aging is the decrease of hyaluronic acid content, which leads to dry and wrinkled skin. Hyaluronidase degrades hyaluronic acid, reducing its viscosity, increasing permeability and leading to extracellular matrix (collagen and elastin fibers) destruction [61]. Recent research demonstrates the hyaluronidase inhibitory activity of CS extracts presumably due to acidic polysaccharides mainly composed of uronic acid [62]. The hyaluronidase inhibitory effect of CS has also been studied in vivo. Administration of a CS‐based cream two times a day improved skin hydration and firmness of 20 human volunteers after 28 days. CS was an effective emollient ingredient, with results similar to hyaluronic acid [63]. The skin compatibility and safety of CS extracts was validated for topical use in vitro using a human skin model and in vivo by patch tests. Results from in vitro and in vivo studies revealed that CS is safe regarding skin irritancy [64]. CS extract added to a body care cream formulation influenced its sensory properties [65]. In vitro studies revealed that the body cream formulation containing CS extract is safe in contact with human skin cells (fibroblasts and keratinocytes) and the patch test carried out with this formulation proved the absence of skin irritation. The formulation significantly improved skin hydration when applied on human ­volunteers [65]. Cream formulations with CS are an interesting option for ­sustainable cosmetic products to improve skin conditions due to their good stability and efficacy. Figure 12.4 summarizes the potential applications of CS in cosmetic products.

365

12  Health Benefits of Silverskin

Antiaging

UV damage protection

UV

Co

ffe

e

s i lv

Emollient properties

ct

366

tr e rs k i n e x

a

Antimicrobial activity

Figure 12.4  Coffee silverskin (CS) skin health-promoting properties for its use as a cosmetic ingredient.

One of the main components of CS is caffeine. Caffeine is being increasingly used in cosmetics due to its high biological activity and ability to penetrate the skin barrier. It stimulates metabolism, contributes to the removal of toxin deposits from the organism, reduces puffy eyes, accelerates drainage of the lymph system from fatty tissue, improves blood microcirculation in the capillary vessels, exhibits anti‐cellulite properties, activates lipolysis, and releases fat excess from adipocyte cells by reducing their size [66]. Other polyphenols present in coffee and also in CS such as CGA have antioxidant properties and may be of great interest for their use in sustainable cosmetic products.

12.5 ­Conclusions CS is a sustainable source of bioactive compounds, such as CGA, caffeine, melanoidins, and dietary fiber, which possesses health‐promoting properties. These components present in CS may be able to reduce the risk of noncommunicable chronic diseases. The usefulness of CS as a novel functional ingredient for metabolic disorders, gastrointestinal and skin health is feasible. However, further experiments should be performed to demonstrate the health‐promoting properties of CS in humans in order to achieve a sustainable health.

­Acknowledgements This research was supported by the SUSCOFFEE (AGL2014‐57239‐R) project. A. Iriondo‐DeHond thanks the Spanish Ministry of Economy and Competitiveness (MINECO) for her predoctoral research fellowship (BES‐2015‐072191).

  ­Reference

R ­ eferences 1 del Castillo, M.D., Fernandez‐Gomez, B., Martinez‐Saez, N. et al. (2016). Coffee Silverskin Extract for Aging and Chronic Diseases. In: Functional Foods for Chronic Diseases. (ed: Martirosyan DM), 386–409. Scotts Valley: CreateSpace Independent Publishing Platform. 2 Costa, A.S.G., Alves, R.C., Vinha, A.F. et al. (2017). Nutritional, chemical and antioxidant/pro‐oxidant profiles of silverskin, a coffee roasting by‐product. Food Chem. 267: 28–35. https://doi.org/10.1016/j.foodchem.2017.03.106. 3 Borrelli, R.C., Esposito, F., Napolitano, A. et al. (2004). Characterization of a new potential functional ingredient: coffee silverskin. J. Agric. Food Chem. 52 (5): 1338–1343. 4 Bresciani, L., Calani, L., Bruni, R. et al. (2014). Phenolic composition, caffeine content and antioxidant capacity of coffee silverskin. Food Res. Int. 61: 196–201. 5 Jiménez‐Zamora, A., Pastoriza, S., and J a, R.‐H. (2015). Revalorization of coffee by‐products. Prebiotic, antimicrobial and antioxidant properties. LWT – Food Sci. Technol. 61 (1): 12–18. http://linkinghub.elsevier.com/retrieve/pii/ S0023643814007348. 6 Ballesteros, L.F., Teixeira, J.a., and Mussatto, S.I. (2014). Chemical, functional, and structural properties of spent coffee grounds and coffee silverskin. Food Bioproc. Tech. 7 (12): 3493–3503. 7 Mesías, M., Navarro, M., Martínez‐Saez, N. et al. (2014). Antiglycative and carbonyl trapping properties of the water soluble fraction of coffee silverskin. Food Res. Int. 62: 1120–1126. http://dx.doi.org/10.1016/j.foodres.2014.05.058. 8 Ateş, G. and Elmacı, Y. (2018). Physical, chemical and sensory characteristics of fiber‐enriched cakes prepared with coffee silverskin as wheat flour substitution. J. Food Meas. Charact. 13 (1): 755–763. https://doi.org/10.1007/ s11694‐018‐9988‐9. 9 Mussatto, S.I. (2015). Generating biomedical polyphenolic compounds from spent coffee or silverskin coffee. In: Coffee in Health and Disease Prevention (ed. V.R. Preedy), 93–106. Amsterdam: Elsevier. 10 Tan, S., Kusumocahyo, S.P., and Widiputri, D.I. (2016). Pulverization of coffee silverskin extract as a source of antioxidant. IOP Conf. Ser. Mater. Sci. Eng. 162 (1) https://doi.org/10.1088/1757‐899X/162/1/012027. 11 Barbosa‐Pereira, L., Guglielmetti, A., and Zeppa, G. (2018). Pulsed electric field assisted extraction of bioactive compounds from cocoa bean shell and coffee silverskin. Food Bioproc. Tech. 11 (4): 818–835. 12 Guglielmetti, A., D’Ignoti, V., Ghirardello, D. et al. (2017). Optimisation of ultrasound and microwave‐assisted extraction of caffeoylquinic acids and caffeine from coffee silverskin using response surface methodology. Ital. J. Food Sci. 29 (3): 409–423.

367

368

12  Health Benefits of Silverskin

1 3 Narita, Y. and Inouye, K. (2012). High antioxidant activity of coffee silverskin extracts obtained by the treatment of coffee silverskin with subcritical water. Food Chem. 135 (3): 943–949. http://dx.doi.org/10.1016/j.foodchem.2012.05.078. 14 del Castillo MD, Ibañez ME, Amigo M, et al. (2013) Application of products of coffee silverskin in anti‐ageing cosmetics and functional food. Patent WO 2013/004873. 15 Panusa, A., Petrucci, R., Lavecchia, R., and Zuorro, A. (2017). UHPLC‐PDA‐ESI‐ TOF/MS metabolic profiling and antioxidant capacity of arabica and robusta coffee silverskin: Antioxidants vs phytotoxins. Food Res. Int. 99 (May): 155–165. 16 Fernandez‐Gomez, B., Lezama, A., Amigo‐Benavent, M. et al. (2016). Insights on the health benefits of the bioactive compounds of coffee silverskin extract. J. Funct. Foods 25 (6): 197–207. http://dx.doi.org/10.1016/j.jff.2016.06.001. 17 Martinez‐Saez, N., Ullate, M., Martin‐Cabrejas, M.a. et al. (2014). A novel antioxidant beverage for body weight control based on coffee silverskin. Food Chem. 150: 227–234. 18 Veronese, N., Solmi, M., Caruso, M.G. et al. (2018). Dietary fiber and health outcomes: an umbrella review of systematic reviews and meta‐analyses. Am. J. Clin. Nutr. 107 (3): 436–444. 19 European Food Safety Authority (EFSA) (2010). Scientific opinion on dietary reference values for carbohydrates and dietary fibre. EFSA J. 8 (3): 1–77. 20 Otles, S. and Ozgoz, S. (2014). Health effects of dietary fiber. Acta Sci. Pol. Technol. Aliment. 13 (2): 191–202. 21 Pourfarzad, A., Mahdavian‐Mehr, H., and Sedaghat, N. (2013). Coffee silverskin as a source of dietary fiber in bread‐making: Optimization of chemical treatment using response surface methodology. LWT – Food Sci. Technol. 50 (2): 599–606. 22 Garcia‐Serna, E., Martinez‐Saez, N., Mesias, M. et al. (2014). Use of coffee silverskin and stevia to improve the formulation of biscuits. Polish J. Food Nutr. Sci. 64 (4): 243–251. http://www.degruyter.com/view/j/pjfns.2013.64.issue‐4/ pjfns‐2013‐0024/pjfns‐2013‐0024.xml. 23 Ateş, G. and Elmacı, Y. (2018). Coffee silverskin as fat replacer in cake formulations and its effect on physical, chemical and sensory attributes of cakes. LWT 90: 519–525. https://doi.org/10.1016/j.lwt.2018.01.003. 24 World Health Organization. (2018) Obesity and overweight. https://www.who.int/ news‐room/fact‐sheets/detail/obesity‐and‐overweight (accessed 11 February 2019). 25 Scuteri, A., Laurent, S., Cucca, F. et al. (2015). Metabolic syndrome across Europe: different clusters of risk factors. Eur. J. Prev. Cardiol. 22 (4): 486–491. 26 Boqué, N., Campión, J., de la Iglesia, R. et al. (2013). Screening of polyphenolic plant extracts for anti‐obesity properties in Wistar rats. J. Sci. Food Agric. 93 (5): 1226–1232. 27 Kobayashi‐Hattori, K., Mogi, A., Matsumoto, Y., and Takita, T. (2005). Effect of caffeine on the body fat and lipid metabolism of rats fed on a high‐fat diet. Biosci. Biotechnol. Biochem. 69 (11): 2219–2223.

  ­Reference

2 8 Cho, A.S., Jeon, S.M., Kim, M.J. et al. (2010). Chlorogenic acid exhibits anti‐ obesity property and improves lipid metabolism in high‐fat diet‐induced‐obese mice. Food Chem. Toxicol. 48 (3): 937–943. 29 del Castillo MD, Fernandez‐Gomez B, Ullate M, and Mesa MD. (2014). Uso de productos de la cascarilla de café para la prevención y tratamiento de las patologías que conforman el síndrome metabólico y sus factores de riesgo. Patente P201431848. 30 Kim, J., Jang, J.Y., Cai, J. et al. (2014). Ethanol extracts of unroasted Coffea canephora robusta beans suppress adipogenesis in preadipocytes and fat accumulation in rats fed a high‐fat diet. Food Sci. Biotechnol. 23 (6): 2029–2035. 31 Narita, Y., Iwai, K., Fukunaga, T., and Nakagiri, O. (2012). Inhibitory activity of chlorogenic acids in decaffeinated green coffee beans against porcine pancreas lipase and effect of a decaffeinated green coffee bean extract on an emulsion of olive oil. Biosci. Biotechnol. Biochem. 76 (12): 2329–2331. 32 Fernández‐Gómez B. (2016). Sustainable use of coffee silverskin as a natural source of bioactive compounds for diabetes. PhD thesis, 87–132. 33 Zheng, G., Qiu, Y., Zhang, Q.‐F., and Li, D. (2014). Chlorogenic acid and caffeine in combination inhibit fat accumulation by regulating hepatic lipid metabolism‐ related enzymes in mice. Br. J. Nutr. 112 (6): 1034–1040. 34 Song, S.J., Choi, S., and Park, T. (2014). Decaffeinated green coffee bean extract attenuates diet‐induced obesity and insulin resistance in mice. Evidence‐based Complement Altern. Med. 2014 http://dx.doi.org/10.1155/2014/718379. 35 Murase, T., Misawa, K., Minegishi, Y. et al. (2011). Coffee polyphenols suppress diet‐induced body fat accumulation by downregulating SREBP‐1c and related molecules in C57BL/6J mice. Am. J. Physiol. Endocrinol. Metab. 300 (1): E122–E133. 36 Rains, J.L. and Jain, S.K. (2011). Oxidative stress, insulin signaling, and diabetes. Free Radical Biol. Med. 50: 567–575. 37 Després, J.P. and Lemieux, I. (2006). Abdominal obesity and metabolic syndrome. Nature 444: 881–887. 38 American Diabetes Association (2016 Dec). Classification and Diagnosis of Diabetes. Diabetes Care 39 (Supplement_1): S13–S22. 39 Kagami, K., Morita, H., Onda, K. et al. (2008). Protective effect of caffeine on streptozotocin‐induced beta‐cell damage in rats. J. Pharm. Pharmacol. 60 (9): 1161–1165. 40 Urzúa, Z., Trujillo, X., Huerta, M. et al. (2012). Effects of chronic caffeine administration on blood glucose levels and on glucose tolerance in healthy and diabetic rats. J. Int. Med. Res. 40 (6): 2220–2230. 41 Abunasef, S.K., Amin, H.A., and Abdel‐hamid, G.A. (2014). A histological and immunohistochemical study of beta cells in streptozotocin diabetic rats treated with caffeine. Folia Histochem. Cytobiol. 52 (1): 42–50. 42 Chen, L., Yu, M., Shen, T. et al. (2015). Impact of caffeine on β cell proliferation and apoptosis under the influence of palmitic acid. Genet. Mol. Res. 14 (2): 5724–5730.

369

370

12  Health Benefits of Silverskin

4 3 del Castillo, M.D., Fernandez‐Gomez, B., Ullate, M. and Mesa MD. (2016). Uso de productos de la cascarilla de café para la prevención y tratamiento de las patologías que conforman el síndrome metabólico y de sus factores de riesgo. WO/2016/097450. Oficina Española de Patentes y Marcas. 44 Fernandez‐Gomez, B., Ramos, S., Goya, L. et al. (2016). Coffee silverskin extract improves glucose‐stimulated insulin secretion and protects against streptozotocin‐induced damage in pancreatic INS‐1E beta cells. Food Res. Int. http://dx.doi.org/10.1016/j.foodres.2016.03.006. 45 Fernandez‐Gomez, B., Ullate, M., Picariello, G. et al. (2015). New knowledge on the antiglycoxidative mechanism of chlorogenic acid. Food Funct. 6 (6): 2081–2090. 46 Karthikesan, K., Pari, L., and Menon, V.P. (2010). Combined treatment of tetrahydrocurcumin and chlorogenic acid exerts potential antihyperglycemic effect on streptozotocin‐nicotinamide‐induced diabetic rats. Gen. Physiol. Biophys. 29 (1): 23–30. 47 del Castillo, M.D., Iriondo‐DeHond, A., Martinez‐Saez, N. et al. (2017). Chapter 6 – Applications of recovered compounds in food products. In: Handbook of Coffee Process By‐Products (ed. C. Galanakis), 171–194. London: Academic Press. 48 Liu, X., Kim, J., Li, Y. et al. (2005). Tannic acid stimulates glucose transport and inhibits adipocyte differentiation in 3T3‐L1 cells. J. Nutr. 135 (2): 165–171. 49 Raid, M.H.A.‐S. (2010). Clinical experimental evidence: synergistic effect of gallic acid and tannic acid as antidiabetic and antioxidant agents. Thi‐Qar. Medi. J. 4 (4): 109–119. 50 Zhou, J., Zhou, S., and Zeng, S. (2013). Experimental diabetes treated with trigonelline: effect on β cell and pancreatic oxidative parameters. Fundam. Clin. Pharmacol. 27 (3): 279–287. 51 Yoshinari, O., Sato, H., and Igarashi, K. (2009). Anti‐diabetic effects of pumpkin and its components, trigonelline and nicotinic acid, on Goto‐Kakizaki rats. Biosci. Biotechnol. Biochem. 73 (5): 1033–1041. 52 Pérez‐Sánchez, A., Barrajón‐Catalán, E., Herranz‐López, M., and Micol, V. (2018). Nutraceuticals for skin care: a comprehensive review of human clinical studies. Nutrients 10 (4): 1–22. 53 Bessada, S.M.F., Alves, R.C., and Oliveira, M.B.P.P. (2018). Applications C. coffee silverskin : a review on potential cosmetic applications. Cosmetics 5 (1): –5. http://www.mdpi.com/2079‐9284/5/1/5. 54 Iriondo‐DeHond, A., Martorell, P., Genovés, S. et al. (2016). Coffee silverskin extract protects against accelerated aging caused by oxidative agents. Molecules 21 (6): 1–14. 55 Pearson, K. (2015). Nutraceuticals and skin health: what are the key benefits and protective properties? J. Aesthetic Nurs. 4 (4): 166–171. http://dx.doi.org/10.12968/ joan.2015.4.4.166. 56 Xue, W. and Warshawsky, D. (2005). Metabolic activation of polycyclic and heterocyclic aromatic hydrocarbons and DNA damage: a review. Toxicol. Appl. Pharmacol. 206 (1): 73–93.

  ­Reference

5 7 Haza, A.I. and Morales, P. (2013). Spanish honeys protect against food mutagen‐ induced DNA damage. J. Sci. Food Agric. 93 (12): 2995–3000. 58 Iriondo‐DeHond, A., Haza, A.I., Ávalos, A. et al. (2017). Validation of coffee silverskin extract as a food ingredient by the analysis of cytotoxicity and genotoxicity. Food Res. Int. 100: 791–797. http://linkinghub.elsevier.com/retrieve/ pii/S0963996917304465. 59 Bakuradze, T., Parra, G.A.M., Riedel, A. et al. (2014). Four‐week coffee consumption affects energy intake, satiety regulation, body fat, and protects DNA integrity. Food Res. Int. 63: 420–427. http://dx.doi.org/10.1016/j.foodres.2014.05.032. 60 Bakuradze, T., Boehm, N., Janzowski, C. et al. (2011). Antioxidant‐rich coffee reduces DNA damage, elevates glutathione status and contributes to weight control: Results from an intervention study. Mol. Nutr. Food Res. 55 (5): 793–797. http://doi.wiley.com/10.1002/mnfr.201100093. 61 Sahasrabudhe, A. and Deodhar, M. (2010). Anti‐hyaluronidase, anti‐elastase activity of Garcinia indica. Int. J. Bot. 6: 299–303. 62 Furusawa, M., Narita, Y., Iwai, K. et al. (2011). Inhibitory effect of a hot water extract of coffee “silverskin” on hyaluronidase. Biosci. Biotechnol. Biochem. 75 (6): 1205–1207. 63 Rodrigues, F., Matias, R., Ferreira, M. et al. (2016). In vitro and in vivo comparative study of cosmetic ingredients Coffee silverskin and hyaluronic acid. Exp. Dermatol. 25 (7): 572–574. 64 Rodrigues, F., Pereira, C., Pimentel, F.B. et al. (2015). Are coffee silverskin extracts safe for topical use? An in vitro and in vivo approach. Ind. Crop Prod. 63: 167–174. http://dx.doi.org/10.1016/j.indcrop.2014.10.014. 65 Rodrigues, F., Sarmento, B., Amaral, M.H., and Oliveira, M.B.P.P. (2016). Exploring the antioxidant potentiality of two food by‐products into a topical cream: stability, in vitro and in vivo evaluation. Drug Dev. Ind. Pharm. 42 (6): 880–889. http://www.ncbi.nlm.nih.gov/pubmed/26393899. 66 Herman, a. and Herman, a.P. (2012). Caffeine’s mechanisms of action and its cosmetic use. Skin Pharmacol. Physiol. 26 (1): 8–14. 67 Costa, A.S.G., Alves, R.C., Vinha, A.F. et al. (2014). Optimization of antioxidants extraction from coffee silverskin, a roasting by‐product, having in view a sustainable process. Ind. Crop Prod. 53: 350–357. 68 Iriondo‐DeHond, A., Ramírez, B., Escobar, F.V., and Del Castillo, M.D. (2019). Antioxidant properties of high molecular weight compounds from coffee roasting and brewing byproducts. Bioactive Compounds Health Disease 2 (3): 48–63. 69 Procentese, A., Raganati, F., Olivieri, G. et al. (2019). Combined antioxidant‐ biofuel production from coffee silverskin. Appl. Microbiol. Biotechnol. 103 (2): 1021–1029. 70 Conde, T. and Mussatto, S.I. (2016). Isolation of polyphenols from spent coffee grounds and silverskin by mild hydrothermal pretreatment. Prep. Biochem. Biotechnol. 46: 406–409.

371

373

13 Cocoa By-products Karen Haydeé Nieto Figueroa1, Nancy Viridiana Mendoza García2, and Rocio Campos Vega1 1 Programa de Posgrado en Alimentos del Centro de la República (PROPAC), Research and Graduate Studies in Food Science, School of Chemistry, Universidad Autónoma de Querétaro (UAQ), Querétaro, México 2 School of Chemistry, Universidad Autónoma de Querétaro, Santiago de Querétaro, Qro, México

13.1 ­Introduction Cocoa (Theobroma cacao L) is an important and economic crop in developing countries. Approximately 20 types of cocoa (T. cacao) are known, and the three most popular types (Criollo, Forastero, and Trinitario) account for 95% of the world’s total cocoa production [1]. The production of cocoa beans in 2016–2017 was 4.7 million tons worldwide. Cote d’Ivoire, Ghana, and Indonesia are the top three producers of cocoa beans, contributing to 67% of the global production. Large quantities of underexploited by‐products are accumulated by removing the beans from the cocoa pods [2]. Once the cocoa dry bean has been obtained, the coproducts that remain consist mainly of three fractions: cocoa pod husk (CPH), cocoa bean shells (CBS), and cocoa mucilage (Figure  13.1) [4], differing widely in chemical composition (Table 13.1). In most cases, these coproducts are underexploited and considered an undesirable “waste” of the cocoa/chocolate industry. Normally, they are left to rot on the cocoa plantation, which can cause environmental problems. Besides producing foul odors, they can propagate diseases, such as black pod rot [4]. Their composition offers potential use for other end products, for example, to obtain bioactive compounds such as dietary fiber (DF), antioxidants, and theobromine (Table 13.2).

Food Wastes and By-products: Nutraceutical and Health Potential, First Edition. Edited by Rocio Campos-Vega, B. Dave Oomah, and Haydé Azeneth Vergara-Castañeda. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

374

13  Cocoa By-products Endocarp1 Mesocarp1 Pod shell/husk2 67–76%

Mucilage/pulp2 8.7–9.9%* Bean shell/husk2 2.1–2.3% Bean1 21–23% (30–40 beans/pod)

Epicarp1

Figure 13.1  The cocoa fruit structures (1) and wastes (2). *By difference. Source: adapted from [3]. Reproduced with permission of Elsevier. Table 13.1  Chemical composition of cocoa bean shell, pod husk, and pulp/mucilage. Bean shell (g/kg dried)

Pod husk (%)

Pulpa (g/100 dm)

Protein

150–181

2.1–9.1

5.47–5.56

Moisture

77–101

6.4–14.1

9.64–9.27

Fat

6.62

5.9–13.0

1.92–1.91

Carbohydrates

17.8

17.5–47.0

68.35–67.99

Ash

7.35

5.9–13.0

7.51–7.68

Lipids

NR

0.6–4.7

NR

NR, no reported a  From two different locations (Cone and Taura) in Ecuador. Source: adapted from references [4–8].

Recently, the valorization of agricultural coproducts has received growing attention, because of the increasing shortage of natural resources and serious environmental problems. Many researchers have attempted to convert such coproducts into food ingredients and for use in other value‐added applications, such as those shown in Figure 13.2. Thus, the use of these coproducts for further exploitation as food additives or supplements of high nutritional value has gained increasing interest because these are high value products and their recovery may be economically attractive [19]. The food industry is experiencing a constantly growing demand for new ingredients from natural sources. This demand has therefore

13.1 ­Introductio

Table 13.2  Nutraceutical composition of cocoa bean shell, pod husk, and pulp/mucilage.

Total dietary fiber (TDF)

Bean shell (%)

Pod husk (%)

Pulpa (g/100 g dm)

50.4–63.6

18.3–59.0

16.75, 16.86

b

Insoluble dietary fiber (IDF)

51.9 ± 0.4

48

0.69, 0.78

Soluble dietary fiber (SDF)

11.7–14.9

11

16.06; 16.11

Lignin

NR

14.7–38.8

NR

Total phenolic (mg GAE/Gg) (TPC)

197.4

46–57

103.8

Theobromine (mg/g)

32.7

0.068

NR

NR, no reported. a  From two different locations (Cone and Taura) in Ecuador. b  Mean ± SE. Source: adapted from references [3, 25, 31, 32, 38, 73, 74, 90, 109, 117].

Cocoa Bean Shell

Cocoa Pod Husk

Cocoa Pulp

Feedstuff

Animal feed

Cocoa juice

Agriculture (composting to suppress weed)

Soap making

Cocoa alcoholic products

Biofuels

Activated carbon

Pectin

Adsorbent (entrap pollutants)

Fertilizer and soil organic matter

Marmalade

Fabric and cotton dying

Paper making

Cocoa jelly

Cacoa pigment (Japanese food industries)

Biofuels and chemical industry

Other products (kefir cocoa beverages)

Food products (nutritional fortification agent, snack)

Food applications (gums)

Extracts • Polyphenol-rich extract • Methylxanthine-rich extract • Fiber-rich extract

Figure 13.2  Applications of cocoa by-products. Source: adapted from references: [1–3, 5–18].

drawn researchers to these ingredients obtained from agro‐industrial coproduct [20]. These coproducts depending on available technology can be converted into commercial products either as raw materials for secondary processes (intermediate food ingredients), operating supplies, or novel ingredients [21].

375

376

13  Cocoa By-products

13.2 ­Cocoa Bean Shell CBS, also referred to as cocoa bean hulls of husks, is the brownish outer covering of the cocoa bean. It is an industrial lignocellulosic waste material produced at cocoa and chocolate factories, especially in industrialized countries, and it forms 12–14% of the roasted cocoa bean. CBS disposal did not appear as a problem in Nigeria when cocoa processing industries were still at the infant stage. However, disposal of this by‐product gradually became an issue with the growth of the industry. The possibility of using this CBS as a potential tropical feed resource and its utilization in animal feed greatly alleviates the disposal problem faced by cocoa processing factories. The dried CBS contains 13.1% crude protein, 13.0% crude fiber, 8.7% ether extract, and 9.1% ash [17]. Considering the global production of cocoa beans, the generation of this waste can be estimated at approximately 700 thousand tons, which is a substantial amount [22]. Recently, the value of agricultural by‐products, such as the cocoa shell, has received increasing attention due to the scarcity of natural resources and serious environmental problems. These by‐products may be used as food ingredients or in other value‐added applications [23]. Thus, further exploration of these products as additives in foods or supplements of high nutritional value has gained increasing interest, primarily due to their nutritional characteristics and secondly to their recovery that can be economically attractive [19]. Additionally, shells are fibrous materials with extremely high strength that can make the grind difficult and may abrade the equipment. In addition, an effective separation of shells and nibs influences the efficiency of the process, the loss of small nib particles along with the shell being financially undesirable. Ideally, in the shelling step, the shell must be perfectly separated, releasing large parts of shells, and the nibs left practically intact [24].

13.2.1  Chemical Composition The composition of cocoa shell is variable, as is that of cocoa beans, and will depend, among other factors, on its origin and the processing to which it has been subjected. The protein content of the cocoa shell (Table 13.1) is very similar to that of cocoa nibs [25]. Unfortunately, 90% of the alpha amino nitrogen in the extracted shell is strongly bound to oxidized polyphenols found in the shell, which are converted into polyphenoquinones. The latter compounds combine with protein– NH2 forming covalent bonds with the elimination of water. It follows, therefore, that only about 1% of the protein in the cocoa shell exists in the free state [8]. The ash content of cocoa shell is similar to the mineral content of several seeds [26]. The ash contains approximately 7% sodium, 3% potassium, 33% sodium carbonate, and a pH of 10.8 [27].

13.2 ­Cocoa Bean Shel

The physical and chemical characteristics of the cocoa shell fat are almost identical to those of cocoa butter, except with regard to acidity. The high acidity of cocoa shell fat can result from the triacylglycerol hydrolysis. This may be due to the bean’s exposure to high temperatures during the roasting process, as the material evaluated in this work was obtained from roasting of whole beans [28]. The predominant fatty acids in cocoa butter are palmitic acid (23.31%), stearic acid (24.51%), and oleic acid (28.74%), while those in the cocoa shell fat are palmitic acid (22.27%) and oleic acid (28.16%) [29]. The nutritional value of cocoa shell fat is greater than that of cocoa butter: for example, the linoleic acid content in cocoa shell fat is almost double that of cocoa butter (7.49 vs. 3.93%). Fatty acids found in cocoa butter in smaller quantities are capric acid (12.95%), myristic acid (4.32%), linoleic acid (3.93%), myristoleic acid (1.29%), and palmitoleic acid (0.95%), while those in cocoa shell fat are capric acid (16.89%), stearic acid (12.05%), linoleic acid (7.49%), myristic acid (3.19%), palmitoleic acid (2.55%), and myristoleic acid (2.43%); lauric acid, tridecanoic acid, and margaric acid are present in trace amounts in cocoa butter and cocoa shell fat [29].

13.2.2  Nutraceutical Composition 13.2.2.1  Dietary Fiber

According to the American Association of Cereal Chemists (AACC), DF is the edible part of plants or analogous carbohydrates that is resistant to digestion and absorption in the human small intestine, with complete or partial fermentation in the large intestine. DF intake has been associated in the past few years with numerous beneficial health effects [30]. DF in 12 varieties of unroasted cocoa shells has previously been determined according to Englyst’s enzymatic–chemical procedure [31]. The total non‐starch polysaccharide ranged from 39.9 to 49.4%, with 13.1–18.6% soluble dietary fiber (SDF) and 24.2–30.8% insoluble dietary fiber (IDF). “Klason lignin” values were between 11.5 and 17.0%. The IDF, SDF, and total dietary fiber (TDF) contents were 35.5, 14.9, and 50.4%, respectively, in roasted cocoa shells with a “Klason lignin” value of 16.1% based on the AOAC method. These values were obtained with shells containing 18.5% fat [25]. Roasted non‐defatted cocoa shells are essentially acid‐resistant (72% H2SO4) tannin–protein–Maillard complexes containing TDF, SDF, and IDFs (63.6, 11.7, and 52% dw, respectively) [32]. DF (total, soluble, and insoluble) powders from cocoa shells were prepared by enzymatic treatment to validate their beneficial in vitro health effects. Powders exhibited significantly (p