Textural Characteristics of World Foods 9781119430698, 1119430690

Table of contents :
Cover
Textural Characteristics of World Foods
© 2020
Dedication
Contents
List of Contributors
Preface
Foreword
Introduction
1 Food Texture – Sensory Evaluation and Instrumental Measurement
Part I -

North America
2
Food Textures in the United States of America
3 Texture Characteristics of US Foods
4 Textural Characteristics of Canadian Foods
Part II -

Middle and South America
5
Textural Characteristics of Traditional Mexican Foods
6 Textural Characteristics of Brazilian Foods
7 Textural Characteristics and Viscoelastic Behavior
of Traditional Argentinian Foods
Part III -

Asia
8
Textural Characteristics of Japanese Foods
9 Textural Characteristics of Chinese Foods
10 Textural Characteristics of Indonesian Foods
11 Textural Characteristics of Thai Foods
12 Textural Characteristics of Malaysian Foods
Part IV -

Oceania
13
Textural Characteristics of Australian Foods
Part V -

Central Asia Middle East
14
Textural Characteristics of Indian Foods
15 Textural Characteristics of Traditional Turkish Foods
16 Textural Characteristics of Iranian Foods
Part VI -

Russia
17
Textural Characteristics of Traditional Russian Foods
Part VII -

Europe
18
Textural Characteristics of Italian Foods
19 Textural Characteristics of Greek Foods
20 Textural Characteristics of British Foods
21 Textural Characteristics of Traditional French Foods
22 Textural Characteristics of Spanish Foods
23 Textural Characteristics of German Foods
24 Textural Characteristics of Traditional Finnish Foods
Part VIII -

Africa
25
Textural Characteristics of Nigerian Foods
Index

Citation preview

Textural Characteristics of World Foods

Textural Characteristics of World Foods Edited by

Katsuyoshi Nishinari Professor, Hubei University of Technology Wuchang, Wuhan China, 430068 Emeritus Professor at Osaka City University Japan

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 Katsuyoshi Nishinari to be identified as the author of the editorial material in 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 Names: Nishinari, Katsuyoshi, editor. Title: Textural characteristics of world foods / [edited by] Prof. Katsuyoshi Nishinari, Wuchang, Wuhan, CH. Description: First edition. | Hoboken, NJ, USA: John Wiley & Sons Ltd, 2019. | Includes bibliographical references and index. | Identifiers: LCCN 2019009266 (print) | LCCN 2019013982 (ebook) | ISBN 9781119430933 (Adobe PDF) | ISBN 9781119430797 (ePub) | ISBN 9781119430698 (hardback) Subjects: LCSH: Food texture. Classification: LCC TX546 (ebook) | LCC TX546.T49 2019 (print) | DDC 641.3–dc23 LC record available at https://lccn.loc.gov/2019009266 Cover Design: Wiley Cover Images: © LIUDMILA ERMOLENKO/Shutterstock, © Rtstudio/Shutterstock, © 9091086/Shutterstock, © Valeria Aksakova/Shutterstock Set in 10/12pt Warnock by SPi Global, Pondicherry, India

10 9 8 7 6 5 4 3 2 1

Dedicated to all the friends who love the conviviality that conquers the hate leading to the war.

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Contents List of Contributors  xix Preface  xxiii Foreword  xxv Introduction

I.1 Why/How/What Do we Eat?  xxvii I.2 Terms for Texture/Taste/Aroma Related to Diverse Foods/Recipes  xxviii I.3 Universality and Diversity  xxix I.4 Wonderful Diversity of World Foods  xxx I.5 Some Pitfalls in Texture Studies  xxxii I.6 About This Book  xxxiii References  xxxiv 1

Food Texture – Sensory Evaluation and Instrumental Measurement  1 Kaoru Kohyama

1.1 ­Introduction: History of Food Texture Studies  1 1.2 Three Methods of Texture Evaluation  3 1.3 Methodologies in Sensory Evaluation of Texture  4 1.4 Instrumental Measurements of Food Texture  6 1.5 Sound Effects  8 1.6 Visual Cues and Flavor Release  9 1.7 Concluding Remarks  9 References  10 Part I  2

North America  15

Food Textures in the United States of America  17 Alina Surmacka Szczesniak

2.1 Introduction 17 2.2 Texture and the American Consumer  17 2.3 Role of Texture in Food Quality and Acceptance  18 2.4 Factors Shaping Attitudes to and Acceptance of Texture  18 2.5 Liked and Disliked Textural Characteristics  20

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2.6 Textural Contrast  23 2.7 Contemporary Trends  23 ­References  25 3

Texture Characteristics of US Foods: Pioneers, Protocols, and Attributes ‐ Tribute to Alina  27 Gail Vance Civille, Amy Trail, Annlyse Retiveau Krogmann, and Ellen Thomas

3.1 The Protocols for Developing a Texture Lexicon  27 3.2 Texture Profiles and Evaluation Protocols for Selected US Foods  30 3.3 Potato Chip Texture Example  31 3.3.1 Serving Protocol  31 3.3.2 Tasting Protocol  31 3.3.3 Potato Chip Texture Summary  31 3.4 Bacon Texture Example  32 3.4.1 Serving Protocol  32 3.4.2 Tasting Protocol  32 3.4.3 Bacon Texture Summary  33 3.5 Peanut Butter Texture Example  34 3.5.1 Serving Protocol  34 3.5.2 Tasting Protocol  34 3.5.3 Peanut Butter Texture Summary  34 ­References  35 4

Textural Characteristics of Canadian Foods: Influences and Properties of Poutine Cheese and Maple Products  37 Laurie‐Eve Rioux, Véronique Perreault, and Sylvie L. Turgeon

4.1 Introduction  37 4.2 Some Historical Perspectives  37 4.3 Canadian Eating Habits  38 39 4.4 Poutine  4.4.1 History of Canadian Cheese Making  40 4.4.2 Manufacture of Cheddar Cheese  41 4.4.3 Cheddar Cheese Composition and Textural Properties  42 4.5 Maple Products  43 4.5.1 History of Making Canadian Maple Products  43 4.5.2 Manufacture of Maple Products  44 4.5.2.1 Transforming Sap into Syrup  44 4.5.2.2 Transforming Syrup into Delights of Various Textures  45 4.5.3 Maple Products Composition and Textural Properties  47 4.5.3.1 Maple Syrup  47 4.5.3.2 Maple Taffy  47 4.5.3.3 Maple Butter  47 4.5.3.4 Maple Sugar Products  48 4.5.3.5 Other Maple Products  49 4.6 Conclusion  49 ­ References  49

Contents

Part II  5

Middle and South America  53

Textural Characteristics of Traditional Mexican Foods  55 Alberto Tecante

5.1 Introduction  55 5.2 Tortillas  55 5.2.1 Corn Tortillas  56 5.2.2 Wheat Tortillas  56 5.2.3 Mechanical Tests  57 5.2.3.1 Rollability 57 5.2.3.2 Bending 59 5.2.3.3 Stress Relaxation in Uniaxial Tension  60 5.2.3.4 Tensile Strength  60 5.2.3.5 Penetration or Puncture  61 5.2.3.6 Kramer Cell  61 5.3 Alegría (Amaranth Seed Sweet)  62 5.4 Ate (Fruit Paste)  62 5.5 Pan de Muerto (Bread of the Dead)  64 5.6 Queso Cotija (Cotija Cheese)  64 5.7 Conclusions  66 ­References  66 6

Textural Characteristics of Brazilian Foods  69 Angelita da Silveira Moreira and Patrícia Diaz de Oliveira

6.1 Formation of Food Habits in Brazil  69 6.1.1 Indigenous Influence  70 6.1.2 Portuguese Influence  70 6.1.3 African Influence  70 6.2 Main Raw Materials and Derived Foods  71 6.2.1 Cassava  71 6.2.1.1 Cassava Flours, Puba Mass, Manipueira, and Tucupi (ABIAP 2018)  72 6.2.2 Amylaceous Derivatives – Sweet Cassava Starch, Tapioca, Tapioca Flour, and Artificial Sago  75 6.2.3 Rice  76 6.2.4 Beans  78 6.3 Trends in Dietary Restrictions  82 ­ References  83 7

Textural Characteristics and Viscoelastic Behavior of Traditional Argentinian Foods  89 Gabriel Lorenzo, Natalia Ranalli, Silvina Andrés, Noemí Zaritzky, and Alicia Califano

7.1 Introduction  89 7.2 Empanadas  90 7.2.1 Viscoelastic Behavior of Commercial Wheat Dough for Empanadas  91 7.2.2 Gluten Replacement in Empanadas: A Complex Task to Cover a Larger Population  93

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7.2.3 7.3 7.3.1 7.3.2 7.3.3 ­

Final Remarks on Empanadas Dough  97 Dulce de Leche  98 Commercial Varieties of Dulce de Leche  99 Dulce de Leche Texture  99 Dulce de Leche‐like Product Enriched with Emulsified Pecan Oil  101 References  103 Part III 

8

Asia  107

Textural Characteristics of Japanese Foods  109 Katsuyoshi Nishinari and Tooru Ooizumi

8.1 Rice  111 8.2 Tofu  113 8.3 Gomatofu (Sesame Tofu)  114 8.4 Some Foods with Mucilaginous Texture  115 8.5 Food for Persons with Mastication Difficulty  115 8.6 Seafood in Japan  115 8.6.1 Sashimi and Marinated Products  117 8.6.2 Surimi Seafood Products  118 8.6.3 Dried Products  121 ­References  121 9

Textural Characteristics of Chinese Foods  125 Long Huang

9.1 9.1.1 9.1.2 9.1.3 9.1.4 9.1.5 9.1.6 9.1.7 9.1.8 9.1.9 9.2 9.3 9.3.1 9.3.2 9.3.3

Regional Cuisine/Foods in China  125 Shandong Cuisine (Lu Cuisine)  125 Canton/Guangdong Cuisine (Yue Cuisine)  125 Szechwan/Sichuan Cuisine (Chuan Cuisine)  126 Hunan Cuisine (Xiang Cuisine)  126 Jiangsu Cuisine (Su Cuisine)  127 Zhejiang Cuisine (Zhe Cuisine)  127 Fujian Cuisine (Min Cuisine)  127 Anhui Cuisine (Hui Cuisine)  127 Cuisines in Autonomous Regions of Tibet and Xinjiang‐Uyghur  127 Texture Descriptive Terms in Chinese  128 Textural Characteristics of Typical Chinese Foods  128 Crust of Mooncake (Yue Bing, Geppei)  128 Chinese Dumpling (Jiaozi, Gyoza, Shao‐Mai, Shumai)  130 Texture Modification to Flour‐Based Chinese Foods, Especially Noodle and Glutinous Dumpling  133 ­References  136 10

Textural Characteristics of Indonesian Foods  137 Oni Yuliarti

10.1 Geographical  137

Contents

10.2 Characteristic of Indonesian Diets  138 10.3 Textural Properties of Indonesian Foods  139 10.3.1 Gel‐Like Foods – Green Jelly Leaves  139 10.3.1.1 Botanical 139 10.3.1.2 Rheological Properties of the Gel  140 10.3.1.3 The Production of the Gel  143 10.3.2 Gel‐Like Foods – Seaweeds  143 10.3.2.1 Botanical 143 10.3.2.2 Gelation and Rheology of Pudding Rumput Laut  144 10.3.2.3 Production of Pudding Rumput Laut  146 10.3.3 Soy‐Based Foods – Tempeh (Fermented Soybeans)  146 10.3.3.1 Texture Properties of Tempeh  148 ­References  149 11

Textural Characteristics of Thai Foods  151 Rungnaphar Pongsawatmanit

11.1 Introduction  151 11.2 Historical and Geographical Background of Thai Food  152 11.3 Selected Food Samples with Sensory Evaluation and Instrumental Measurement  156 11.4 Health Benefit of Thai Food  160 ­References  163 12

Textural Characteristics of Malaysian Foods: Quality and Stability of Malaysian Laksa Noodles  167 Lai Hoong Cheng, Yan Kitt Low, A’firah Mohd Sakri, Jia Shin Tai, and Abd Karim Alias

12.1 Introduction  167 12.2 Chemical Composition  168 12.3 Organoleptic Quality  168 12.4 Textural Quality  169 Factors Affecting Textural Quality of Laksa Noodles  170 12.5 12.5.1 Rice Grain  175 12.5.2 Aged Rice  175 12.5.3 Milling Method  175 12.5.4 Particle Size of Rice Flour  175 12.5.5 Steaming Process  176 12.5.6 Blending of Other Starch/Starches  176 12.5.7 Extrusion and Boiling  176 12.5.8 Washing  176 12.6 Storage Stability  176 12.7 Nutritional Quality  178 12.7.1 Gluten Free  178 12.7.2 Low‐Fat Carbohydrate Choice  178 12.8 Conclusion  178 Acknowledgments  178 ­ References  179

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Contents

Part IV  13

Oceania  181

Textural Characteristics of Australian Foods  183 Andrew Halmos, Lita Katopo, and Stefan Kasapis

13.1 Introduction  183 13.2 Importance of Mouthfeel and Its Recognition  184 13.3 Developments in Mouthfeel and Texture Terms  184 13.4 Typical Meals with Descriptors for the Australian Palate  185 13.5 Breakfast  186 13.5.1 Toasted Bread  186 13.5.2 Cereals with Milk  186 13.5.3 Coffee  187 13.5.4 Fried Tomatoes  188 13.5.5 Steak, Sausages, or Chops  188 13.5.6 Eggs  188 13.5.7 Bacon  188 13.5.8 Spreads  188 13.6 Lunch or Mid‐Day Meal  189 13.6.1 Sandwiches with Fillings  189 13.6.2 Pie, Sausage Roll, or Pastry  189 13.6.3 Potato Products  189 13.6.4 Boiled or Steamed Vegetables  189 13.6.5 Vegetables with Roux  189 13.6.6 Salads and Dressings  190 13.6.7 Meat  190 13.7 Dinner  190 13.7.1 Soup  190 13.7.2 Meat in the Form of Chops or Steak  190 13.7.3 Seafood  190 13.7.4 Fish  191 13.7.5 Rice  191 13.7.6 Vegetables  191 13.7.7 Chinese‐Style Food  191 13.7.8 Cheeses  192 13.7.9 Sweets  192 13.7.10 Ice Cream  193 13.7.11 Snacks 193 13.8 Conclusions  193 ­References  193 Part V  14

Central Asia Middle East  197

Textural Characteristics of Indian Foods: A Comparative Analysis  199 Amardeep Singh Virdi and Narpinder Singh

14.1 Introduction  199 14.2 Chapati  201

Contents

14.3 Gluten‐Free Chapatis  205 14.4 Biscuits and Cookies  205 14.5 Gluten‐Free Cookies and Biscuits  207 14.6 Noodles  208 14.7 Gluten‐Free Noodles  210 14.8 Bread  211 14.9 Gluten‐Free Bread  212 14.10 Muffins and Cakes  213 14.11 Gluten‐Free Muffins and Cakes  214 14.12 Conclusion  215 Acknowledgments  216 ­References  216 15

Textural Characteristics of Traditional Turkish Foods  223 Mahmut Doğan, Duygu Aslan, and Fatima Tahseen Miano

15.1 Introduction  223 15.2 Textural Characteristics of Traditional Turkish Meat‐Based Food Products  224 15.2.1 Sucuk (Turkish‐Type Fermented Sausage)  224 15.2.2 Pastırma (A Traditional Dry‐Cured Meat Product)  225 15.3 Textural Characteristics of Traditional Turkish Cheeses  227 15.4 Textural Characteristics of Traditional Turkish Desserts  231 15.4.1 Turkish Delight (Lokum)  231 15.4.2 Helva  232 ­References  234 16

Textural Characteristics of Iranian Foods: Cuisine Signifies Old Historical Identities  237 Bahareh Emadzadeh and Behrouz Ghorani

16.1 Iran Geography at a Glance  237 16.2 The Impact of Geography and History  237 Distinctive Features of Persian Cuisine  239 16.3 16.4 Bread  239 16.4.1 Sangak  240 16.4.2 Barbari  240 16.4.3 Taftoon  241 16.4.4 Lavash  241 16.5 Rice  242 16.5.1 Rice‐Based Foods  242 16.5.2 Rice Cooking  242 16.5.2.1 Stewing of Rice by Steam  243 16.5.3 Rice‐Based Sweets and Desserts  243 16.6 Kebabs  243 16.7 Lighvan Cheese  244 16.8 Gaz: A Well‐Known Confectionary  245 16.9 Doogh: A Fermented Dairy‐Based Drink  246 16.10 Conclusion  246 ­References  247

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Part VI  17

Russia  251

Textural Characteristics of Traditional Russian Foods  253 Nataliia Ptichkina and Nataliia Nepovinnykh

17.1 Introduction  253 17.2 Formation History of Russian Cuisine  253 17.3 Textural Characteristics of Some Traditional Products  255 17.4 Bread from Rye Flour  255 17.5 Jellies from Meat and from Fish (Kholodets)  257 17.6 Soup‐Purée Based on Pumpkin Powder  258 17.7 Sauces  259 17.8 Curd Cheese Dishes  261 17.9 Kissels and Jellied Desserts  262 17.10 Aerated Desserts  263 Acknowledgments  265 ­References  265 Part VII  18

Europe  269

Textural Characteristics of Italian Foods  271 Rossella Di Monaco, Nicoletta Antonella Miele, Sharon Puleo, Paolo Masi, and Silvana Cavella

18.1 Introduction  271 18.2 Cheese  271 18.2.1 Pasta Filata Cheese  274 18.2.2 Cooked Curd Cheeses  275 18.2.3 Other Italian Cheeses  277 18.3 Salumi  277 18.3.1 Italian Dry‐Cured Ham  278 18.3.2 Salami 281 18.3.3 Mortadella 282 18.4 Bread  282 18.5 Conclusions  285 ­References  286 19

Textural Characteristics of Greek Foods  293 Stefan Kasapis

19.1 Background  293 19.1.1 Olive Oil  293 19.2 Traditional Greek Cheeses  296 19.2.1 Feta 297 19.3 Health Conscious Feta Manufacturing  298 19.3.1 Texture Profile Analysis of Feta  298 19.3.2 Full and Low Fat Greek Yogurts  299 19.4 Popular Emulsion‐Type Meat Products  300

Contents

19.5 Conclusions  301 ­References  301 20

Textural Characteristics of British Foods  305 Andrew J. Rosenthal and Tim J. Foster

20.1 Introduction – What Are British Foods?  305 20.2 Roast Beef and Yorkshire Pudding  306 20.2.1 Culinary Background to the Dish  306 20.2.2 Nature of the Raw Materials  306 20.2.3 Textural Considerations  307 20.3 Fish and Chips  307 20.3.1 Culinary Background to the Dish  307 20.3.2 Nature of the Raw Materials  308 20.3.3 Textural Considerations  309 20.4 Conclusions  310 ­ References  311 21

Textural Characteristics of Traditional French Foods  313 Bernard Launay

21.1 Introduction  313 21.2 Change in Texture Awareness: What and Why?  314 21.2.1 The “New Cuisine” Style  314 21.2.2 Restaurants of Foreign Cuisine  314 21.2.3 Fast‐Food Restaurants  314 21.2.4 Changes Attributable to the Development of Industrial Food Products  315 21.2.5 Texture Measurement in Industry and Research Labs  315 ­Acknowledgment  318 ­References  318 22

Textural Characteristics of Spanish Foods: Dry‐Cured Ham  319 Susana Fiszman and Amparo Tarrega

22.1 Introduction  319 22.2 Production of Dry‐Cured Ham  320 22.2.1 Salting/Post‐Salting  320 22.2.2 Ripening  321 22.3 Sensory Quality of Dry‐Cured Ham  321 22.4 Sensory Assessment of Dry‐Cured Ham  322 22.4.1 Texture Attributes  323 22.4.2 Appearance Attributes  324 22.4.2.1 Color 324 22.4.2.2 Odor and Flavor Attributes  325 22.4.3 Other Sensory Techniques  325 22.4.4 Factors Affecting the Sensory Features of Dry‐Cured Ham  325 22.5 Instrumental Texture Techniques for Dry‐Cured Ham  326 22.5.1 Instrumental TPA  326

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22.5.2 22.5.3 22.6

Warner‐Bratzler Test  327 Other Instrumental Methods for Measuring Texture Features  327 Instrumental Methods for Determining Sensory Features Other than Texture  328 22.7 Health‐Related Aspects of Dry‐Cured Ham  328 22.8 Final Remarks  330 ­Acknowledgments  330 ­References  330 23

Textural Characteristics of German Foods: The German Würstchen  335 Norbert Raak, Klaus Dürrschmid, and Harald Rohm

23.1 Introduction  335 23.2 Basic Technologies of Sausage Manufacture  336 23.2.1 Rohwurst  336 23.2.2 Brühwurst  337 23.2.3 Kochwurst  337 23.3 Sausage‐Related Culture, Stories, and Recent Trends  337 23.4 Evaluation of Texture and Rheological Properties of Sausages  342 23.5 Typical Sausage Side Dishes and Condiments  346 ­References  348 24

Textural Characteristics of Traditional Finnish Foods  353 Liisa Lähteenmäki and Karin Autio

24.1 Introduction  353 24.2 Rye Bread  354 24.2.1 Sensory Attributes  354 24.2.2 Textural Measurements  354 24.2.3 The Effect of Ingredients and Processing Conditions on Structural Properties  356 24.3 Oat β‐Glucan  356 Sensory Attributes  356 24.3.1 24.3.2 Rheological Properties  357 ­References  358 Part VIII  25

Africa  361

Textural Characteristics of Nigerian Foods  363 Matthew Olusola Oluwamukomi and Olaide Samuel Lawal

25.1 Introduction  363 25.2 Classification of Foods Based on Their Rheological/Textural Characteristics  364 25.3 Foods That Flow and Do Not Require Any Chewing During Oral Processing (Newtonian and Non‐Newtonian Fluids)  364 25.3.1 Newtonian Fluids  364 25.3.1.1 Palm Wine  365 25.3.1.2 Pito 365

Contents

25.3.1.3 Kunun from Cereal  365 25.3.1.4 Nunu from Milk  365 25.3.1.5 Otika 366 25.3.1.6 Burukutu 366 25.3.2 Non‐Newtonian Fluids  366 25.3.2.1 Ketchup 366 25.3.2.2 Draw Soups: (Ogbono, okra, ewedu)  366 25.4 Semisolid Foods That Are Processed in the Mouth by Squeezing the Tongue and Palate  367 25.4.1 Pasting Properties of Starch Pastes (Ogi, Tuwo, Amala, Lafun, or Pupuru)  367 25.4.1.1 Ogi/Akamu Porridge/Agidi from Maize  369 25.4.1.2 Tuwo from Maize  370 25.4.1.3 Gari / Eba from Cassava  370 25.4.1.4 Pounded Yam (iyan) or Yam Fufu from Yam  372 25.4.1.5 Amala (Amala isu) from Yam  372 25.5 Soft‐Solid Foods That Require Chewing but Do Not Have “Crispy” Attributes  373 25.5.1 Akara from Cowpeas  373 25.5.2 Warankasi from Milk  375 25.6 Hard‐Solid Foods Are Crispy and Associated with a Crunchiness  375 25.6.1 Ipekere Agbado (Maize Fritters)  376 25.6.2 Maize Kokoro  376 25.7 Conclusion  377 ­References  377 Index  385

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List of Contributors Abd Karim Alias

Lai Hoong Cheng

Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia

Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia

Silvina Andrés

Gail Vance Civille

Center for Research and Development in Food Criotechnology (CIDCA), Faculty of Cs. Exactas, Department of Chemical Engineering, Faculty of Engineering, National University of La Plata (UNLP), CICPBA, CONICET, La Plata, Argentina

Sensory Spectrum, Inc., New Providence, New Jersey, USA

Duygu Aslan

Engineering Faculty, Department of Food Engineering, Erciyes University, Kayseri, Turkey Karin Autio

VTT Technical Research Center, Otaniemi, Espoo, Finland Alicia Califano

Center for Research and Development in Food Criotechnology (CIDCA), Faculty of Cs. Exactas, Department of Chemical Engineering, Faculty of Engineering, National University of La Plata (UNLP), CICPBA, CONICET, La Plata, Argentina Silvana Cavella

Center of Food Innovation and Development in the Food Industry (CAISIAL), and Department of Agricultural Sciences, University of Naples‐Federico II, Portici, Naples, Italy

Rossella Di Monaco

Center of Food Innovation and Development in the Food Industry (CAISIAL), and Department of Agricultural Sciences, University of Naples‐Federico II, Portici, Naples, Italy Patrícia Diaz de Oliveira

Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil Mahmut Doğan

Engineering Faculty, Department of Food Engineering, Erciyes University, Kayseri, Turkey TAGEM Food Analysis Center Co., Erciyes University Technopark, Kayseri, Turkey Klaus Dürrschmid

Institute of Food Science, Universität für Bodenkultur Wien, Vienna, Austria Bahareh Emadzadeh

Research Institute of Food Science and Technology, Mashhad, Iran

xx

List of Contributors

Susana Fiszman

Bernard Launay

Spanish National Research Council, Madrid, Spain

Department of Science and Engineering for Food and Bioproducts, AgroParisTech, Centre de Massy, France

Tim J. Foster

School of Biosciences, Nottingham University, Sutton Bonington Campus, Loughborough, United Kingdom

Olaide Samuel Lawal

Behrouz Ghorani

University of Birmingham, Edgbaston, Birmingham, United Kingdom

Research Institute of Food Science and Technology, Mashhad, Iran Andrew Halmos

School of Science, RMIT University, Bundoora West Campus, Melbourne, Victoria, Australia Long Huang

Guangxi Neober Food Sci-Tech Co Ltd, Hezhou, Guangxi, China Changzhou Neober Biotech Co Ltd, Changzhou, Jiangsu, China Stefan Kasapis

School of Science, RMIT University, Bundoora West Campus, Melbourne, Victoria, Australia Lita Katopo

School of Science, RMIT University, Bundoora West Campus, Melbourne, Victoria, Australia Kaoru Kohyama

Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan Annlyse Retiveau Krogmann

Sensory Spectrum, Inc., New Providence, New Jersey, USA Liisa Lähteenmäki

Department of Management, MAPP, Research on Value Creation in the Food Sector, Aarhus University, Aarhus, Denmark

Department of Chemistry, The Federal University Oye Ekiti, Ekiti, Nigeria Peter Lillford

Gabriel Lorenzo

Center for Research and Development in Food Criotechnology (CIDCA), Faculty of Cs. Exactas, Department of Chemical Engineering, Faculty of Engineering, National University of La Plata (UNLP), CICPBA, CONICET, La Plata, Argentina Yan Kitt Low

Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia Paolo Masi

Center of Food Innovation and Development in the Food Industry (CAISIAL), and Department of Agricultural Sciences, University of Naples‐Federico II, Portici, Naples, Italy Fatima Tahseen Miano

Engineering Faculty, Department of Food Engineering, Erciyes University, Kayseri, Turkey Institute of Food Science and Technology, Sindh Agriculture University, Tando Jam, Sindh, Pakistan Nicoletta Antonella Miele

Center of Food Innovation and Development in the Food Industry (CAISIAL), and Department of Agricultural Sciences, University of Naples‐Federico II, Portici, Naples, Italy

List of Contributors

Nataliia Nepovinnykh

Saratov State Agrarian University, Saratov, Russia Katsuyoshi Nishinari

Hubei University of Technology, Wuhan, China Matthew Olusola Oluwamukomi

Department of Food Science and Technology, Federal University of Technology, Akure, Ondo State, Nigeria Tooru Ooizumi

of Cs. Exactas, Department of Chemical Engineering, Faculty of Engineering, National University of La Plata (UNLP), CICPBA, CONICET, La Plata, Argentina Laurie‐Eve Rioux

Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, Quebec, Canada GastronomiQc Lab Joint Research Unit, a joint initiative of Université Laval and ITHQ Harald Rohm

Department of Marine Science and Technology, Fukui Prefectural University, Obama, Fukui, Japan

Chair of Food Engineering, Institute of Natural Materials Technology, Technische Universität Dresden, Dresden, Germany

Véronique Perreault

Andrew J. Rosenthal

Quebec Institute of Tourism and Hotel Management (ITHQ), Montreal, Quebec, Canada GastronomiQc Lab Joint Research Unit, a joint initiative of Université Laval and ITHQ Rungnaphar Pongsawatmanit

Kasetsart University, Bangkok, Thailand Nataliia Ptichkina

School of Biosciences, Nottingham University, Sutton Bonington Campus, Loughborough, United Kingdom A’firah Mohd Sakri

Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia Angelita da Silveira Moreira

Saratov State Agrarian University, Saratov, Russia

Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil

Sharon Puleo

Narpinder Singh

Center of Food Innovation and Development in the Food Industry (CAISIAL), Department of Agricultural Sciences, University of Naples‐Federico II, Portici, Naples, Italy

Alina Surmacka Szczesniak

Norbert Raak

Department of Food Science and Technology, Guru Nanak Dev University, Amritsar, Punjab, India Mount Vernon, New York, USA

Chair of Food Engineering, Institute of Natural Materials Technology, Technische Universität Dresden, Dresden, Germany

Jia Shin Tai

Natalia Ranalli

Amparo Tarrega

Center for Research and Development in Food Criotechnology (CIDCA), Faculty

Food Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Penang, Malaysia Spanish National Research Council, Madrid, Spain

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List of Contributors

Alberto Tecante

Amardeep Singh Virdi

Facultad de Química, Departamento de Alimentos y Biotecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico

Department of Food Science and Technology, Guru Nanak Dev University, Amritsar, Punjab, India

Ellen Thomas

Sensory Spectrum, Inc., New Providence, New Jersey, USA

School of Chemical and Life Sciences, Singapore Polytechnic, Singapore, Singapore

Amy Trail

Noemí Zaritzky

Sensory Spectrum, Inc., New Providence, New Jersey, USA

Center for Research and Development in Food Criotechnology (CIDCA), Faculty of Cs. Exactas, Department of Chemical Engineering, Faculty of Engineering, National University of La Plata (UNLP), CICPBA, CONICET, La Plata, Argentina

Sylvie L. Turgeon

Institute of Nutrition and Functional Foods (INAF), Laval University, Quebec City, Quebec, Canada GastronomiQc Lab Joint Research Unit, a joint initiative of Université Laval and ITHQ

Oni Yuliarti

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Preface We all know that the food texture is one of the dominating factors that influence ­consumers’ preference of a food product and willingness of next purchase. The texture of a food is closely associated with its structure at both the macro‐ and micro‐level, and it therefore has very important implications to other sensory properties, in particular the taste and aroma, because the release of small molecules depends on the pattern of food structure breakdown. I understand why consumers often prefer to say a food “tastes good,” but I believe that understanding a food to be “mouth‐feels good” could be fundamentally more important in relation to consumers’ acceptance and preference of a food product. Even though food texture has been commonly used as a single term and in some cases used as an alternative to mouth‐feel, it is as a matter of fact a collective term consisting of a wide range of textural properties. The physical stimulus (or stimuli) to each textural feature could originate from the structural and geometrical contributions (and some other contributions, e.g. moisture or oil content), or their combination. No complete list of textural properties is yet available, but in the Japanese language, more than 400 textural terms/properties have been identified, covering features perceived by touching, seeing, and even hearing. Therefore, the description, definition, and — more importantly — the instrumental characterization of textural properties are not easy tasks and remain as a major challenge to food texture research. Human beings are very fortunate that a great variety of food is available at different seasons and in different regions. While such a diversity of food sources is welcomed by consumers, a big complexity arises due to the diverse texture terms being used by consumers across the globe because of different culture and different languages. Research has already shown evidence of various texture preferences by consumers of different cultural backgrounds. Research also shows that the same texture term could have ­delicate differences between consumers speaking different languages. While texture diversity should be celebrated for making our lives much more interesting and pleasurable, it brings a big challenge to the food industry now that its markets reach across the globe. This book is the first of such kind to give detailed insights into the texture diversity of foods across at all major regions of the world. Cultural, linguistic, as well as technical explanations of food texture are brilliantly integrated in this book.

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I thank Professor Nishinari for his great effort in getting this book organized and published. His expert knowledge of food texture demonstrated in this book is hugely valuable to texture researchers in both industry and research institutes throughout the world. Jianshe Chen Zhejiang Gongshang University Hangzhou, China

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­Foreword We know that eating is one of the great unifying pleasures of life. Everywhere and in every culture, we celebrate by eating, and despite the warnings of an emerging obesity crisis, nutritionists find it very difficult to persuade people that too much of it can be bad for them. Furthermore, we are warned that our obvious pleasure in eating good food, when coupled with the growing population and its affluence, is leading to a global crisis as demand outstrips supply. This can only be managed if we understand much more about what we eat and why we like it. We know that essential nutrients can be provided via liquid diets, and flavor and aroma can be managed much more easily in liquid systems, but there is something about chewing and breaking down food to swallow it that we enjoy  –  perhaps just because it prolongs or provides complexity to our senses? So, texture is one of foods’ most important qualities and is a sensation perceived by us all. But how do we perceive it, and what do we prefer? Why is there such diversity in the food products eaten around the world? This book will not answer all these questions, but it provides a wonderful insight into the range of textures we eat and some suggestions as to why. For the scientist and industrial technologist, the complexity of the questions are fascinating research topics requiring continuous investigation. This book begins with tributes to the founders of this inquiry, its current state of development, and the opportunities that modern techniques of mechanics and human physiology can bring to the table. Others readers may regard texture as “gestalt,” implying that no amount of reductionist measurement science will (or should) codify the design rules for texture creation and its pleasurable impact. Whatever philosophy the reader prefers, this book provides a fascinating survey of what has been created by thousands of skilled empirical developments, converting agricultural produce to an almost limitless array of eating pleasures. Peter Lillford University of Birmingham, Birmingham, UK

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­Introduction Katsuyoshi Nishinari

I.1 ­Why/How/What Do We Eat? What do we expect from food? Food supplies energy and nutrition. We eat food when we feel hungry. This has been known to be controlled by the feeding center and satiety center in the hypothalamus in the brain. Since the discovery of leptin, a hormone ­regulating food intake, the understanding of the mechanism of food intake has greatly advanced. Now, the mechanism of food intake is being studied further, and it is thought that the central nervous system in addition to hypothalamus is governing the food intake. Food has such a physiological function, but also has psychological or cultural aspects that have not been understood completely by physiology. The mechanism that explains why people lose their appetite in dejection caused by events such as the death of beloved persons, a broken heart, or being scolded has not been identified. Food has a special function to unite people by conviviality. This function plays important roles to strengthen family ties in daily life, but was also used by feudal kings and aristocrats to tame or govern subordinates. People like to eat special foods on the occasion or the turning point in their lives such as birthday, marriage, and funeral. Selection of foods depend on the preference, which is influenced by culture and economic status. Food processing/cookery has assured the safety by sterilization and removal of harmful ingredients, storage, and transportation, as well as improving the palatability. Texture has been known to be the most important attribute determining the palatability, and has recently attracted more and more attention in relation to the safe delivery of food into digestive organs without causing choking or aspiration (i.e. the wrong transport of masticated foods or liquids bolus into the airway instead of to the esophagus then stomach). In addition to these urgent problems, the interaction between the food and oral organs governed by brain function has attracted much attention, although these are not yet well understood. Thin liquids are known to be swallowed faster than thick liquids. Firm foods are masticated more strongly and the number of chews is greater than for soft foods. Are firmer foods chewed slower or faster than soft foods? Or is the chewing speed independent of firmness? It may depend not only on the firmness but also on aroma and taste (Nishinari and Fang 2018). Society for Mastication Science and Health Promotion was founded by Kinziro Kubota in Japan in 1990. The collaboration among dentists, food scientists, and related disciplines is thought to be important. People tend to prefer softer processed foods that do not need

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mastication. As a result, the jaw is degenerated and the space for teeth to grow is becoming insufficient, and thus the problem of snaggleteeth/irregular teeth can become serious. The growth of the dental industry in developed countries indicates that people do not want to be deprived of the gratifying sensations that arise from eating their food. From the nutritional standpoint, it is possible to have a completely adequate diet in the form of fluid foods that require no mastication. However, few people are content to live on such a diet. It clearly shows that people want to continue to enjoy the textural sensations that arise from masticating their food (Bourne 2002). Bourne raises the following reasons for masticating food: gratification, comminution, mix with saliva, temperature adjustment, released flavor, and increased surface area. The link between reduced mastication ability and hippocampal neuron loss has been suggested, which might indicate that chewing plays a role in fending off dementia. Saito examined the number of chewing using restored menus in each era in Japanese history. According to his examination, the restored menu for Himiko, queen of Yamatai in the third century, was found to need 3990 chews taking 51 minutes, 1366 chews and 31 minutes for Murasaki Shikibu (the author of Tale of Genji in the tenth to eleventh century), 2654 chews and 29 minutes for Minamoto Yoritomo (the first warrior Shogunate) in the end of twelfth century, 1465 chews and 22 minutes for Tokugawa Ieyasu (who established Edo Bakufu Shogunate in 1603) while only 620 chews and 11 minutes for a common menu in the present. The decreasing tendency of the number of chews is a reflection of the decrease in the intake of tough/firm/hard foods. Many reports have been published that eating slowly with much mastication reduces the likelihood of obesity. Will this gradual change of food texture from firm to soft continue? Although the invention of softening of firm foods by enzymatic action that retains food appearance is good news for persons with difficulty in mastication, the decrease in chewing cycles sometimes results in fast eating, overeating, and obesity for normal persons. Bolhuis et al. (2014) and Forde et al. (2016) reported that smaller bite (amount of food ingested in the mouth) sizes and more chewing increased oro‐sensory exposure time and slowed the eating rate, thus providing a stronger satiety response per energy consumed. While many studies have reported that the expected satiation increased with increasing thickness/hardness for liquid/solid foods, and texture is more important determinant for expected satiation and thus for the selected portion size of food, other factors such as the means of consumption (e.g. using straw or spoon), affecting the eating rate, could not be neglected. It is also expected that a creamy flavor will cause a higher satiation than fruity flavor, but this remains inconclusive (Hogenkamp et al. 2011). Texture and flavor are the two most important determinants of food consumption in addition to the cost, and their respective roles and interaction should be studied further.

I.2 ­Terms for Texture/Taste/Aroma Related to Diverse Foods/Recipes Is there a relationship between the two representing systems of written language, alphabets (phonetics) and ideograms, and the universality/diversity problem? Ancient Egyptians used hieroglyphics representing shapes of all the things around them, and ancient Chinese used also hieroglyphic characters engraved on bones and

­Introductio

tortoise shells. Origins of letters seem to be not so different. It can be imagined that ancient people devised these tools for communication by representing the shape faithfully and then simplified these shapes. However they came to their language, people of world now speak more than 7000 languages (although not all of these have a written equivalent, and many of these are spoken only by a small number of people). In an attempt to improve communication, Polish doctor L. L. Zamenhof invented what he hoped could be a universal language, Esperanto, although it has not gained many users/ speakers. While most languages have evolved into alphabets that represent only sounds (i.e. phonetics, without specific meaning), Chinese‐based languages have kept the enormous number of hieroglyphic characters. However, the characters were simplified in the twentieth century in mainland China and Singapore; Japan and Taiwan retain the traditional Chinese characters. The number of Chinese characters was thought to be about 50 000, but the publication of the largest Chinese character dictionary Zhonghua Zihai (simplified Chinese: 中华字海) compiled in 1994 listed 85 568 different characters. It is thus difficult to determine the exact number of Chinese characters. I had a lucky experience to be nourished by a Chinese family during my stay in the United Kingdom and was given different dish every day for more than six months. I enjoyed different dish every day for 180 days! This family knew so many recipes! Is this diversity of dishes related to the enormous number of Chinese characters? Japan is known to have the largest number of texture terms – about 500. In his visits to Japan, Bourne was impressed by the textural diversity of Japanese foods (Bourne 2002). The great number of texture terms represents the deep attachment to texture difference of foods. The high ratio of the Japanese texture terms is onomatopoetic (Nishinari et al. 2008; Hayakawa 2015). Onomatopoetic representation of the texture is similar to the hieroglyphic representation of things. Only a slight difference of the appearance, shape, size, color, sound, etc. requires a different term in onomatopoeia, just as in the enormous number of characters in Egyptian or Chinese hieroglyphic representation. There has been no systematic published study on the relation between the actual sound one hears during mastication and the onomatopoeic word chosen to represent the sound. Is it determined by anatomic structural difference of organs in the oral cavity or in the cultural difference originated in one’s personal environmental background, historical, geographical, or education? It is well known that the onomatopoeic words for birds and other animals are different in English, French, and other languages, and therefore, these cultural differences partly account for differences in the onomatopoeia. Whether physiological difference or cultural differences are more important has not been studied, as far as the author is aware.

I.3 ­Universality and Diversity For most physicists, it is valuable to understand a phenomenon by a simple equation symbolized by a Newton’s law of motion. Although all the events in the universe seem to be very complicated, we can understand the essence of the event by extracting the most important core of the event. Thus, physics made a great progress, and humans succeeded in understanding many events/phenomena. While the physicists have won a

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great success, the biologists still face a great deal of mystery, although the field has also  seen many great achievements. Physicists like the universality, while botanists/ zoologists/microbiologists are interested in discovering the distinctions that identify new species or in the phenomenon where many factors intersect, making the simplification – extraction of the essence – difficult. They pay more attention to the diversity, although they also try to find some universal law that can explain biological phenomena (Nishinari et al. 2016). Goethe’s Faust reflects the thought of the biblical book Ecclesiastes that there is nothing new under the sun. Goethe is known to have discovered the incisive bone, and therefore he should have known that before and after the discovery, human knowledge is changed. He also disagreed with Newton’s analytical understanding of the nature. He wrote that nature should be grasped totally and should not be shredded into separated parts (Thuillier 1980). Thus, his thought “nothing new under the sun” should mean that human nature, mind, and feeling are essentially the same and not changed from the ancient times to his age. Therefore, the phrase “under the sun” represents “in the human mind.” However, our way of thinking and feeling is strongly influenced by the environment, which has been modified by science and technology. In the sixteenth century, a French monk Francois Rabelais wrote Gargantua and Pantagruel, giving advice on a wide range of best practices. Imagine what he would say if he could have used a washlet to clean himself after defecation instead of the downy feathers of a goose’s neck. Japanese Food Guide Spinning Top, proposed in Japan in 2005, uses easily understood illustrations to show desirable combinations of food groups and their approximate quantities. It was formulated by the Ministry of Health, Labour and Welfare (MHLW) and Ministry of Agriculture, Forestry and Fisheries (MAFF). In this representation, not only the intake of the combination of diverse foods but also the importance of exercise is emphasized, because if the top stops spinning, it falls over. It is well‐known that exercise improves the appetite for diverse foods, although instead of healthy exercise, some immoral ancient Romans were reported to vomit to empty their stomach to create room for another favorite food. In the extreme, if one eats only one cup of noodles as a meal, this is surely against the recommendation of the Food Guide. Even if one is busy, one should not forget that continuing to eat such a simple meal will lead to health problems. Thus, enjoying a well‐balanced meal is not only an enjoyable but also a necessary duty for humans to be free from illness and to reduce the burden on a nation’s resources.

I.4 ­Wonderful Diversity of World Foods As we can see in this book, different foods are eaten in each country. Each nation has its own food materials and enjoy different taste, aroma, and texture. Their raw materials are different, and way of cooking and processing are different. Texture, taste, and aroma interact, and the texture is the most important attributes to determine the palatability of foods, especially in staple food such as rice, bread, noodle, and potatoes, which mostly have no strong taste and aroma (Szczesniak 1963; Bourne 2002; Nishinari and Fang 2018). Most humans enjoy the meals, and feel happy when they eat palatable foods with beloved persons, families, and friends. This pleasure to share the enjoyment with others is specific for humans, although animals give food to their children during nursing.

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Humans have learned to share the pleasure with others in the course of building community. Since many nations wish to live peacefully with other nations, this shared pleasure should prevail all over the world. Readers will find that many different palatable foods are enjoyed in different countries, and will be interested in traveling to different countries to experience different foods/culture. Foods can unite all the humans peacefully. This book is a collection of more than 20 chapters, each describing the textural characteristic of traditional and special foods in each country. We can learn from the traditional and special foods that are liked by people in each country. People are generally conservative in the preference of foods, but if they recognize the merit of new foods that might add to enjoyment and might also help people recovering from illnesses or surgery, these new foods attract much attention and prompt the industry explore more new products. Readers may find it interesting to compare the different preferences of the texture for cooked rice in Japan, Europe, and India. Readers may learn new ideas to improve food processing and distribution. Chapters address not only texture but the flavor release, as well as the relation between the texture and taste/aroma. Recently, palatability has been shown not only to add enjoyment but also contribute to health by improving appetite and saliva secretion, and other physiological functions such as immunity and stress; the interleukin was found to increase in rats that were fed with sweet feeds while corticosterone was found to increase in rats fed with bitter feeds. As Brillat‐Savarin says: The pleasure of the table belongs to all ages, to all conditions, to all countries, and to all areas; it mingles with all other pleasures, and remains at last to console them for their departure. … The discovery of a new dish confers more happiness on humanity than the discovery of a new star. A so‐called China’s Brillat‐Savarin, Yuan Mei also talked about the pleasure of the table. Food companies are required to make products with many kinds of characteristics in response to consumer demand. Diversity is not only reflected in foods and in culture; science and the arts also reveal the value of diversity. Misuzu Kaneko, a wonderful Japanese poet who unfortunately committed suicide, is loved by many Japanese including myself still today. The poet chanted, “Minna chigatte minna ii,” which I like so much and which has been translated by perhaps more than hundred Japanese persons, as exemplified in the internet: Everyone is different. That is what makes them wonderful. Everyone has his/her own wonderful personality. Everyone is different from others, and has value of existing, etc. A poet could be and should be and tries to create a new original expression that has sometimes never been used, and thus uses a special word that might not be understood immediately or move readers immediately. Sometimes the art will be understood only by a small group of people. Likewise, it is good to be able to enjoy different foods in the travel – to savor the diversity and find enjoyment in the experience. However, food has additional requirements. It must be not only palatable but also be safe. It must not be too expensive, and it must be sustainable, which is a task for food science and technology. I would like to unify the universality and diversity, and wish readers to enjoy each chapter and become friendly with many countries. I thank all the contributors of the book. It is my hope that readers will gain a greater appreciation for the important role of texture as they read this book. I am happy to see that my friends Amos Nussinovitch

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and Madoka Hirashima published a book “More Cooking Innovations – Novel Hydrocolloids for Special Dishes” complementing their previous book “Cooking Innovations – Using Hydrocolloids for Thickening, Gelling and Emulsification”, both published from CRC Press.

I.5 ­Some Pitfalls in Texture Studies After affirming and admiring the diversity of world foods, I must note that we should better to understand each other by using the common words to avoid the calamity of the biblical Tower of Babel, in which languages were so confused that people were unable to communicate meaningfully. Foods that are masticated are broken down into small fragments by the teeth and mixed with saliva, thus being sufficiently lubricated to be swallowed (Hutchings and Lillford 1988). This mouth process model has been taken into account by many texture research groups as the starting point for understanding the oral processing (Chen and Engelen 2012). Although the mouth process model of Hutchings and Lillford is very versatile and schematizes concisely the dynamic nature, it does not specify the force or the distance quantitatively and never mentions the effect of smell and taste, which influences the mastication behavior. The interaction among different sensations texture, taste, and odor is still a matter of debate. The texture profile analysis (TPA) has been widely used to quantify the textural characteristics of solid foods. This is a simple experiment to compress by a plunger a sample food placed on a flat base of the uniaxial compression machine, and then record the force. Usually, the compression speed is chosen so that it is closer to the mastication speed, but unfortunately, some commercially available machines do not allow the experimenter to use such a compression rate. In addition, in normal mastication the lower teeth in the mandible are raised to contact with the upper teeth so that foods can be broken down effectively, but in the TPA measurement the distance between the plunger and the base, called the clearance, cannot be set to zero to protect the force sensor. When the hardness is defined by the peak force, it is necessary to write the cross‐sectional area of the sample because the force is almost doubled when the area is doubled. It is also a pity that so many published papers lack the information of the compression rate,which seriously affects the value of hardness (Bourne 2002; Nishinari and Fang 2018). The adhesiveness is defined by the negative peak force or the area enclosed by the force curve and the base line (usually time), and is usually interpreted as the degree of stickiness of foods to the oral organ, teeth, tongue, and palate. However, no‐rubber‐like sample is broken down after the first compression, and the surface area of the sample could not be defined uniquely. Therefore, to determine the adhesiveness, it is better to choose a larger clearance so that the area of the sample can be easily defined (Brenner and Nishinari 2014). The ratio of the area of the force enclosed by the first compression to that of the second compression is called cohesiveness, and it is interpreted as the internal forces that maintain the structure of foods. Therefore, very brittle foods such as biscuits don’t recover the height after they are broken down by the first compression; the second compression does not detect any force, leading to a 0 cohesiveness value. It is

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understandable that more deformable elastic foods such as surimi or dessert jelly may recover the initial height after the first compression, and therefore these foods many show comparatively higher value of cohesiveness. However, if this method is applied to liquids such as water, it is evident that the cohesiveness is equal to 1 because the level of water in a container will fully recover the initial height before the second compression begins. Is the cohesiveness of water is so high? Researchers working in dysphagia treatment say that yogurt‐like texture is ideal to prevent the aspiration because it is cohesive, meaning that the broken down fragment stick each other, which is called cohesive. But this “cohesiveness” is much different from the highest cohesiveness value of 1 shown by water, and is thought to be most dangerous for dysphagic patients because it is least cohesive! Thus, it is dangerous to apply TPA directly to liquid foods in the container (Nishinari et al. 2013, 2019a, b). The plots of breaking stress σb against breaking strain εb are frequently used to classify the texture of foods, e.g. the ratio of σb/εb is called gel rigidity and used in the surimi community in Japan. It is evident, however, that this schematic presentation does not distinguish the strain hardening and strain softening because this ratio is obtained from only two points, the origin and the breaking point, and does not take into account whether the curve is convex (strain softening) or concave (strain hardening). Small‐amplitude oscillational shear measurements have been introduced to understand the texture correlating with structure, but unfortunately sometimes, the artifacts were reported because of the slippage between the sample and the geometry of the apparatus. This is mostly caused by the syneresis. It is recommended to use waterproof sandpaper because serrated geometry commercially available is not sufficient to prevent the slippage, and/or to use the uniaxial deformation, which is free from slippage (Nishinari and Fang, 2018).

I.6 ­About This Book The editing of the book started from the obituary for Alina Szczesniak, a pioneer of texture studies, who contributed a chapter “Food Textures in the United States of America” in a book New Encyclopedia of Mouthfeel (Eds. K. Nishinari, F. Nakazawa, K.  Katsuta, J. Toda), which was published in 1999 only in Japanese by the Japanese publisher Science Forum (Tokyo). The Part of the book contains six chapters contributed by Long Huang (on China), Bernnard Launay (on France), Stefan Kasapis and Dimitrios Boskou (on Greece), Karin Autio and Liisa Lähteenmäki (on Finland), Andrew Halmos (on Australia), Alina Szczesniak (on USA). As I was writing her obituary, I felt obliged to publish her chapter, together with other contributions, in English. One of the editors, Jun Toda, fortunately kept ­copies of her manuscripts, and the director of the publisher Science Forum Motoyama generously allowed us to use these manuscripts. Szczesniak’s chapter has not lost  its  value but contains a lot of important descriptions. Her faithful coworker Gail Vance Civille and her team contributed additional information to complement Szczesniak’s chapter. It was not an easy task for each author to write textural characteristics of foods in his/ her country. I feel happy and grateful to all the contributors for their great effort. I would like to thank all the editing team of Wiley, Cheryl, Bobby, Saleem, Atthira, Menon

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and other persons all who participated for publishing this book. I hope that this book is enjoyable and wish the readers happy reading. Bon appétit! (Enjoy your meals!)

­References Bolhuis, D.P., Forde, C.G., Chen, Y. et al. (2014). Slow food: sustained impact of harder foods on the reduction in energy intake over the course of the day. PLoS One 9: e93370. Bourne, M.C. (2002). Food Texture and Viscosity, 2e. New York: Academic Press. Brenner, T. and Nishinari, K. (2014). A note on instrumental measures of adhesiveness and their correlation with sensory perception. J. Texture Stud. 45: 74–79. Chen, J. and Engelen, L. (eds.) (2012). Food Oral Processing: Fundamentals of Eating and Sensory Perception. Chichester, UK: Wiley‐Blackwell. Forde, C.G., Leong, C., Chia‐Ming, E. et al. (2016). Fast or slow‐foods? Describing natural variations in oral processing characteristics across a wide range of Asian foods. Food Funct. https://doi.org/10.1039/C6FO01286H. Hayakawa, F. (2015). Vocabularies and terminologies of food texture description and characterization. In: Modifying Food Texture Vol. 2: Sensory Analysis, Consumer Requirements and Preferences (eds. J. Chen and A. Rosenthal), 3–18. Amsterdam: Woodhead, Elsevier. Hogenkamp, P.S., Stafleu, A., Mars, M. et al. (2011). Texture, not flavor, determines expected satiation of dairy products. Appetite 57 (3): 635–641. Hutchings, J.B. and Lillford, P.L. (1988). The perception of food texture – the philosophy of the breakdown path. J. Texture Stud. 9: 103–115. Nishinari, K. and Fang, Y. (2018). Perception and measurement of food texture – solid foods. J. Texture Stud. 49: 160–201. Nishinari, K., Fang, Y., Mleko, S. et al. (2016). Food Science and Technology from a Japanese Perspective. Poland: University of Life Sciences in Lublin. ISBN: ISBN 978‐83‐63657‐64‐2 www.perfekta.info.pl tel.81 46 10 229. Nishinari, K., Fang, Y., and Rosenthal, A. (2019a). Human oral processing and texture profile analysis parameters – bridging the gap between the sensory evaluation and the instrumental measurements. J. Texture Stud. 50: 1–12. Nishinari, K., Turcanu, M., Nakauma, M., and Fang, Y. (2019b). Role of fluid cohesiveness in safe swallowing. NPJ Science of Food 3: 5. Nishinari, K., Hayakawa, F., Xia, C. et al. (2008). Comparative study of texture terms: English, French, Japanese, and Chinese. J. Texture Stud. 39: 530–568. Nishinari, K., Kohyama, K., Kumagai, H. et al. (2013). Parameters of texture profile analysis. Food Sci. Technol. Res. 19: 519–521. Nishinari, K., Nakazawa, F., Katsuta, K. et al. (1999). New Encyclopedia of Mouthfeel. Tokyo: Science Forum. Szczesniak, A. (1963). Classification of textural characteristics. J. Food Sci. 28: 385–389. Thuillier, P. (1980). Le petit savant illustré. Paris: Seuil. Translated from French into Japanese by Koide, S., Nishinari, K and Terada, M. (1984) Han=Kagakushi, Shin‐ Hyoron, Tokyo.

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1 Food Texture – Sensory Evaluation and Instrumental Measurement Kaoru Kohyama Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan

1.1 ­Introduction: History of Food Texture Studies Various types of foods are consumed across the worlds. Humans have experienced different food textures and carried on the tradition during the sharing of their foods over many generations, but it is not known when texture studies of foods first began. The great scientist Robert Hooke, after from Hookean solids are named, explained the principle of elastic deformation of solids, and Isaac Newton, who founded the law governing the flow of simple liquids (Newtonian fluids), may be included in the founding of texture studies. A great number of works were published more than 100 years ago (Bourne 2002, pp. 26–27), but food texture as a main study subject appears to have originated in the late 1950s (Szczesniak 2002). As texture is defined as “all the mechanical, geometrical and surface attributes of a product perceptible by means of mechanical, tactile and, where appropriate, visual and auditory receptors” (ISO 11036 1994), food texture is perceived as the physical characteristics of food experienced by humans; therefore, only humans can perceive and describe texture (Szczesniak 2002). Texture analyses that combine a sensory evaluation and an instrumental measurement have been widely performed since the 1960s. Alina S. Szczesniak and Malcolm C. Bourne, who both passed away in 2016 (Nishinari and Fang 2018), were great pioneers of food texture studies from the viewpoints of sensory evaluation and physics, respectively. Many sensory and instrumental measurements of food texture have been published in a myriad of publications such as the Journal of Texture Studies (1970–) and others (Kohyama 2018). Later, a variety of methods are introduced. In 2015, the United Nations adopted 17 sustainable development goals (SDGs) for the 2030 Agenda (United Nations 2015). Foods are produced and processed in a globally sustainable system as shown in Figure 1.1 (Kohyama 2015). The physical properties of food materials are dramatically changed during each step in the process, and the magnitude of this change is generally significant. The physical properties and structures in

Textural Characteristics of World Foods, First Edition. Edited by Katsuyoshi Nishinari. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

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1  Food Texture – Sensory Evaluation and Instrumental Measurement Food Industry

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Food Processing (“Pre-oral Processing”) Eating Bolus Swallow Agriculture Digestion Absorption

Bite size Oral Processing

Figure 1.1  Food processing system accompanied by changes in texture. Source: Edited from Kohyama (2015, p. 139).

the early stages of food processing, where raw materials are not eaten, and those in the digestive stages after swallowing are less important for texture. Most textural information of foods is sensed manually just before eating and orally during oral processing in the food system. When we eat, a bite‐size food is processed using the tongue and teeth, and then subsequently swallowed. The time required for oral processing is very short, approximately 1 second for a liquid such as water, 10 seconds for thick liquids and semisolids, and 100 seconds for hard solid foods (Kohyama 2015). Physical properties of food never reach an equilibrium state during this short period: The food structure is broken down, mixed with saliva, and a bolus is prepared for swallowing (Hutchings and Lillford 1988; Chen 2009; Koç et al. 2013; Kohyama 2015; Lillford 2018; Nishinari and Fang 2018). The oral stage has been more extensively studied (Chen 2009), and a series of international conferences named “Food Oral Processing” has been organized every two years since 2010. Recently, Jeltema et al. (2015) suggested that food texture is determined by the preferred manner of oral processing or mouth behaviors of each person. There are four distinct patterns (chewer, cruncher, smoother, and sucker) of mouth behaviors, with subjects belonging to different groups perceiving food textures of the same food differently. The mouth behaviors of consumers must be considered in designing the texture of a food. Aging decreases oral adaptation to food textures in healthy individuals, and oral impairments such as tooth loss can also change eating behaviors (Peyron et al. 2017). Oral processing can be skipped if well‐homogenized diets are served, which is the case for infant foods and diets for those with dysphagia (Cichero 2017). However, oral processing is required for the perception of food texture and flavor, and for enjoyment of food as an essential part of life (Kohyama 2015). The perception of food texture for each individual is determined according to one’s capabilities, physical activities, hunger/thirst, and other physiological states such as the time of the day and environmental conditions. The relationships between objective measurements, subjective sensory perceptions, and consumer preferences must be clearly addressed (Tunick 2011).

1.2  Three Methods of Texture Evaluation Feature

Method

Observed object

Discipline

Subjective

Sensory evaluation

Perceived texture

Psychophysics

Perception Human measurement

Oral processing During eating

Objective

Instrumental analysis

Modulation

Oral physiology

Oral receptors

Food properties structure

After starting oral processing

Before oral processing Physics/Chemistry

Figure 1.2  Methods for the evaluation of food texture. Source: Edited from Kohyama (2015, p. 139).

1.2 ­Three Methods of Texture Evaluation Figure  1.2 shows the evaluation methods of food texture (Wilkinson et  al. 2000; Kohyama 2015). Texture is assessed by subjective sensory evaluations based on psychophysics and by objective instrumental measurements based on physics and/or chemistry. Texture and related physical properties can be evaluated by instruments that measure rheology, fracture, and acoustics as well as by microscope and spectrometers, which are able to characterize the structure of materials. These instrumental and sensory results are often inconsistent. In addition to the nonequilibrium nature of food texture mentioned above, other reasons for this inconsistency could be the time during which the instruments are used (before oral processing), while differ from the time of the sensory evaluations, which are typically performed after the initiation of oral processing. In addition, there is a nonlinear relationship between the magnitude of what can be perceived by the human senses and the intensity of the physical stimuli from food. Conditions such as temperature, moisture due to saliva, chewing movements, and food deformation rates during oral processing are not well mimicked by conventional instruments and can influence instrumental results (Bourne 2002, pp. 33–57, 347–368). As Szczesniak and Bourne (1969) previously reported, panelists change the methods for manually determining firmness. The viscosity principle is used for soft foods such as puddings; deformation by gentle squeezing is used for firmer foods such as bread and tomatoes; puncture forces using a finger are utilized for pears and apples; and the flexing principle is used for raw carrots. Shama and Sherman (1973) reported that the orally perceived viscosities of a wide range of liquids and semi‐solid foods can be perceived at different shear stresses and strains. Shear stress, which is caused by the tongue squeezing at a low shear rate around 10 s−1, can be used to assess the viscosity of highly viscous foods such as chocolate spread, lemon curd, and peanut butter, whereas different shear rates and a similar low shear stress can be used for liquids with low viscosity. Moreover, humans are able to modify how they process food according to the texture perceived (Figure 1.2).

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To eliminate the data gap between the objective and subjective methods, it is necessary to examine the physical changes that foods undergo during oral processing (Nishinari and Fang 2018). Human physiological measurements can relate the physicochemical properties measured by instruments and the perceived textures evaluated by sensory panelists (Wilkinson et  al. 2000; Bourne 2002, pp. 293–319; Koç et  al. 2013; Kohyama 2015). Instead of instruments, sensors that detect load, displacement, vibration, strain, etc. are often housed in the instruments are attached to human subjects who eat the food in the physiological methods. The output values from the sensors are objective, similarly to those of instrumental analyses, and the mode of oral processing is the same as for the sensory evaluations. The force or pressure, kinematics, and muscle activities are objectively measured during oral processing, and these values correspond to load, deformation, and energy measurements obtained by instrumental evaluations of food texture (Kohyama 2015). Bourne (1975) stated that instrumental measurements based on rheology, the study of the deformation and flow, are only able to describe a fraction of the physical properties sensed by the mouth: changes in size (comminution), moisture (hydration due to saliva), temperature, and surface roughness during oral processing. Tribological measurements are related to mouthfeel during oral processing (Chen 2009; Chen and Stokes 2012; Stokes et al. 2013). When the thickness of the food placed on the surface of the oral organ is large (> 100 μm), combined with a normal first bite and during an early stage of oral processing, the bulk properties relating to thickness, firmness, crispness, melting, and breakdown predominate. Rheology is most useful as an instrumental method in cases of large deformation rheology and fracture testing in solid foods. When the thickness of the food is 0.1–100 μm after some oral processing the mixing of the food particles with saliva or liquids from the food causes the creaminess, smoothness, and slipperiness that can be analyzed by tribology (Chen and Stokes 2012; Stokes et al. 2013). When the thickness is in the nm–μm range, the food surface properties related to astringency, roughness, and homogeneity predominate. During the late stage of oral processing, a bolus is formed and swallowed, and some residual attributes can then be sensed. These qualities can also be studied by rheology and tribology (Stokes et al. 2013).

1.3 ­Methodologies in Sensory Evaluation of Texture Texture is a complicated attribute that is derived from a number of words used to describe an attribute (Szczesniak 2002). Based on an examination of consumers’ awareness of texture, Szczesniak and colleagues at the General Foods Corporation Technical Center proposed a definition and classification for texture characteristics (Szczesniak 1963). They developed standard rating scales for hardness, brittleness, chewiness, gumminess, viscosity, and adhesiveness for quantitative evaluation of food texture (Szczesniak et al. 1963), and proposed the texture profile method (Brandt et al. 1963). These approaches are the basis of the international standards of sensory analysis and have been modified over time. The texture profile method has been widely used as the standard method (ISO 11036). Developing a texture lexicon and classifying texture terms have reported globally, and international comparative studies of texture terms have been conducted (Jowitt 1974;

1.3  Methodologies in Sensory Evaluation of Texture

Drake 1989; Nishinari et al. 2008; Antmann et al. 2011; Hayakawa 2015; Arboleda and Arce‐Lopera 2017). The most frequently used texture term in Japan is “hard–soft,” although “crisp” is more frequently used in the United States and Austria (Bourne 2002, p. 5). The Japanese use several different ideograms expressed as different Chinese characters (kanji) to describe the terms, such as hard, firm, stiff, tough, and rigid, which are pronounced as ka‐ta‐i in Japanese (Hayakawa et al. 2013; Nishinari and Fang 2018). Drake (1989) provided a list of 54 texture and rheology terms translated from English into 22 different languages (Bahasa, Chinese, Czech, Danish, Dutch, Finnish, French, German, Greek, Hindi, Hungarian, Icelandic, Irish, Italian, Japanese, Norwegian, Polish, Portuguese, Spanish, Swedish, Tagalog, and Welsh). A word in one language was sometimes used to describe multiple texture attributes that were described by distinguishable terms in another language. Drake pointed out that misunderstandings, confusion, and inconsistencies might occur during such translations. Currently, standard texture lexicons are available for download on the websites of the International Organization for Standardization (https://www.iso.org/iso/iso_catalogue.htm) and the ASTM International: (www.astm.org) (Hayakawa 2015). Texture terms often include onomatopoeias (Yoshikawa et al. 1970; Hayakawa et al. 2005, 2013; Antmann et al. 2011; Hayakawa 2015). As listed by Yoshikawa et al. (1970) and Hayakawa et al. (2005), there are more than 400 Japanese terms for texture, a much greater number than in other languages (Bourne 2002; p. 5). There are also many onomatopoetic and mimetic Japanese terms for texture (Hayakawa et al. 2013). The sensory texture profiling procedure was developed by Szczesniak et  al. in the early 1960s (Brandt et  al. 1963; Szczesniak 2002; Bourne 2002, pp. 257–286). Some modifications to the basic texture profile analysis (TPA) procedure have been made. Sensory texture measurements are made primarily by touch, although appearance and sound sometimes provide important information for the texture profile of a food product. The major steps in the sensory texture profile are (i) panel selection, (ii) panel training, (iii) establishment of standard rating scales using standard products, (iv) establishment of a basic score sheet for the TPA, and (iv) development of a comparative TPA score sheet for each commodity. Texture is typically analyzed using selected terms and the extent to when and how a panelist touches and treats or manipulates a product. Sensory evaluation includes several steps that occur both outside and inside the mouth. Examples of the latter steps are the first bite, the early and late stages of mastication, swallowing, and the residual feel of the food in the mouth and throat (Brandt et al. 1963; Szczesniak 2002). Some mechanical properties such as firmness, fracturability, and viscosity are perceived during the first bite, whereas gumminess, chewiness, and adhesiveness are evaluated during the masticatory stage, and mouth‐coating is perceived late or as residual attribute after swallowing. Quantitative descriptive analysis (QDA) is a technique for characterizing the perceived sensory attributes in quantitative terms (Stone et al. 1974). Descriptive analysis has been the main tool in sensory science for the acquisition of detailed, reliable, and reproducible data to describe sensory profiles. Check‐all‐that‐apply (CATA) is a simple and fast sensory profiling tool that is often used in consumer studies (Lazo et al. 2016). Panelists check all sensory attributes from the list; however, the magnitudes of the selected attributes are not analyzed. The above‐mentioned methods are used to describe sensory attributes at a defined moment. Sensory texture evaluation during oral processing has evolved to include

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dynamic sensory evaluations, which are used to analyze temporal changes in textural attributes. Time intensity (TI) is a method during which a panelist sequentially describes the intensity of a selected attribute (Lee III and Pangborn 1986; Cliff and Heymann 1993; Jack et al. 1994; Sprunt et al. 2002; Le Révérend et al. 2008). In the method of temporal dominance of sensations (TDS), a panelist continuously chooses the strongest attribute at each moment from a list of attributes (Labbe et al. 2009; Pineau et al. 2009; Cheong et al. 2014; Fiszman and Tarrega 2018). For time check‐all‐that‐apply (TCATA), a panelist checks all perceived attributes at successive moments (Ares et  al. 2015; Castura et al. 2016). Panelists do not quantify the magnitudes in the latter two methods, but the ratio of panelists who check an attribute provides information on the intensity of the attribute at each moment. Sherman (1969) proposed an amended texture profile shortly after that described by Szczesniak et al. The only criterion in Sherman’s classification was whether the characteristic is a fundamental property or is derived from a combination of two or more attributes. The primary characteristics are analytical composition, particle size and shape; the secondary characteristics are elasticity, viscosity, and adhesion; and the tertiary characteristics are mechanical properties such as hard, brittle, plastic, crisp, creamy, soggy, and sticky, so on. Sensory attributes are evaluated at different stages of the oral processing (Chen 2009; Koç et al. 2012; Nishinari and Fang 2018). The initial properties of a food such as firmness, deformability, and springiness are manually perceived. Oral processing accompanies a sequential perception of texture: compression between the tongue and palate, the first bite, repeated chewing or mastication, bolus formation, swallowing, and residual mouthfeel.

1.4 ­Instrumental Measurements of Food Texture Objective evaluation methods using instruments for texture measurements have been categorized into three types: fundamental, empirical, and imitative (Scott‐Blair 1958; Rosenthal 1999; Bourne 2002, pp. 107–112). Fundamental methods are based on materials science, such as rheology, and provide well‐defined physical properties. Typical examples are Young’s modulus, dynamic shear modulus and viscosity coefficients, but they often fail to explain the textural characteristics perceived by humans. When humans touch a material, their perceptions are not in accordance with the idealized hypothesis of a fundamental measurement. The ratio of deformation of soft food materials extends over the linear region of force and deformation, and humans evaluate texture prior to the point where a food sample reaches an equilibrium state. Better correlations to sensory scores have often been obtained using empirical methods rather than fundamental methods. Values measured by empirical tests are more poorly defined than those measured by fundamental tests, but they can be related to texture from practical experiences. Many instruments are developed to provide numerical values, but these measured values cannot be compared if they are obtained from different instruments. Some examples of empirical tests are using the Magness‐Taylor puncture tester for fruit hardness, the Bloom Gelometer for gelatin jelly strength, the Kramer Shear Press for hardness of processed fruits, vegetables and legumes, and the Warner‐Bratzler Shear machine for meat tenderness (Bourne 2002, pp. 189–233). Many

1.4  Instrumental Measurements of Food Texture

of these tests can be performed using universal testing instruments, as these attachable probes are commercially available, but users must be reminded that the measured values depend on the test conditions. Imitative methods attempt to simulate the conditions to which the food is subjected to human action. As the instrument mimics human movements, obtained empirical parameters help explain the texture perceived by humans. Instrumental TPA has been widely used since it was proposed in the 1960s. Originally, TPA was conducted with a Texturometer (Figure 1.3a) (Friedman et al. 1963), in which a probe mimics a molar tooth. The movement of the probe resembles chewing, and two‐sequential bites are performed, even though the location of the food and the lower molar is upside‐down. Texture parameters such as hardness, adhesiveness, and cohesiveness can be objectively obtained from the resulting ­ force–time curve (Figure 1.3b). Szczesniak (1968) found that the parameters obtained from the TPA measurements were well correlated to the sensory scores generated by a trained panel. After several years, Bourne proposed a modified two‐bite TPA using an Instron universal testing machine (Bourne 2002, p. 185). As the test is performed by uniaxial movements at a constant speed, the resultant force–time curve is easily converted into a force–distance curve (Figure 1.4). The area under the curve is defined as the work or energy used in physics, and the work used for compression and decompression can be analyzed separately, as A4 and A5 in Figure 1.4. The area under the curve for the first or second compression (A1 and A2 in Figure 1.4) represents the compressive work, and the negative force area during the first decompression (A3) is adhesiveness that is also defined as work. Other parameters such as hardness and springiness also have dimensions (Sherman 1969; Bourne 2002, p. 186). At present, most two‐bite TPAs have been conducted using a similar type of instrument. The TPA method has been applied to food boli gathered from the mouths of humans, and changes in texture during oral processing were objectively analyzed (Shiozawa et al. 1999). According to the Consumers Affairs Agency of the Japanese government, semi‐ solid and thickened liquids prepared for dysphagic individuals are currently evaluated using this method (Nishinari et al. 2013). As these samples flow away, they are placed in (a)

(b)

Cohesiveness =

A2 A1

Force

Hardness A1

A2

B

A3

Adhesiveness = A3 Time

Figure 1.3  Texture profile analysis (TPA) using a Texturometer. (a) Main part of a Texturometer and (b) example of a TPA curve with typical parameters. Source: Edited frοm Szczesniak (2002, p. 219).

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1  Food Texture – Sensory Evaluation and Instrumental Measurement Hardness H1

Fracturability

Hardness H2

Force

8

Total Area A1

A4

A2

A5 A3

Adhesive force

Time

Figure 1.4  Texture profile analysis using a universal testing machine. Source: Edited from Bourne (1978, p. 63).

a vessel. The hardness, adhesiveness, and cohesiveness are then determined using the TPA method. The misuse of the cohesiveness values that decrease as viscosity increases must be avoided during the interpretation of data.

1.5 ­Sound Effects Crisp foods such as crackers, potato chips, fresh fruits, and vegetables make sounds when they are broken, though some foods do not produce sounds. The sounds are due to the rupture of the cell walls. Crackers and snacks are dry crisp foods that contain only air in the cells; whereas fruits and vegetables are wet crisp foods that contain fluid in their cells (Tunick 2011). The work performed by external forces is stored as elastic potential energy, which is liberated as acoustic energy when the foods are ruptured. Sounds have been measured to evaluate the texture of these foods. Drake has pioneered studies of food‐crushing sounds (Drake 1963), and Vickers conducted combined studies of perceived crispness and sound measurements in foods (Vickers and Bourne 1976, Vickers 1984). Vickers (1984) suggested that crispness and crunchiness are related to pitch and loudness of crushing sounds, and Dacremont (1995) analyzed the spectral components of chewing sounds. Recently, eating sounds were studied using onomatopoeic expressions across different languages (Arboleda and Arce‐Lopera 2017). The fracturability of a food relates to the sounds made while the food is bitten and chewed. More recently, crisp food sounds have been measured using an acoustic envelope detector coupled with a texture analyzer for the simultaneous measurements of

1.7  Concluding Remarks

force displacement and sound pressure generated by the fracture of crisp food samples (Chen et al. 2005; Taniwaki and Kohyama 2012; Demattè et al. 2014). Sounds during oral processing were found to influence the perceived texture of potato chips and ­carbonated drinks in recent psychological trials (Zampini and Spence 2004, 2005) that Ig‐Novel Nutrition Prize was awarded in 2008.

1.6 ­Visual Cues and Flavor Release Humans can perceive the viscoelastic properties of a food using visual information alone without touching the material. Viscosity can be estimated by flow rate, and rigidity can be evaluated by the degree of deformation. Geometric characteristics and surface properties can also be judged visually. Structural information observed using microscopy and spectroscopy is widely used in materials science. The range of the spatial scale for properties that are visually perceptible is similar to that of the tactile special threshold: approximately 1–2 mm for passive touch determined by two‐point discrimination and more than 10 times lower (0.02–0.1 mm) for active touch with free movement of the tongue and other organs (Kohyama 2015). The time scale that is perceptible by humans must be also considered. It would be approximately 0.1– 100 seconds, which is the same as the time for oral processing (Kohyama 2015). Visual and structural information that falls outside of these ranges is excluded from texture analyses according to the definition of texture (ISO 11036) perceived by human receptors. Visual sensations are not assessed during oral processing because the food inside the mouth cannot be seen (Kohyama 2015). Instead, taste and retronasal aroma play more important roles, as they are released from food matrix in the mouth. These properties can be perceived during oral processing and undergo dynamic changes. These chemical stimuli sensed by taste and olfactory receptors affect the texture perceived using tactile, kinesthetic, temperature, and auditory receptors. Although these receptors detect each stimulus, multi‐modal sensory integration occurs through the cross‐modal interactions of these receptors during the perception of food characteristics (Verhagen and Engelen 2006; Bult et al. 2007).

1.7 ­Concluding Remarks To inform food texture for consumers who have not experienced a particular food product, which is very common in other cultures/languages/countries, the use of appropriate texture terms is difficult. Currently, texture expressions using audiovisual information are common in presentations and advertisements on television and social network services such as Cookpad. Tactile displays have been studied using virtual reality and augmented reality in this century (Peruzzini et al. 2012; Ung et al. 2018). As virtual tactile displays need neither real food materials nor translation of texture terms, its actual application to food science is expected to provide a better understanding of the textural characteristics of foods in the future.

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­References Antmann, G., Ares, G., Varela, P. et al. (2011). Consumers’ texture vocabulary: results from a free listing study in three Spanish‐speaking countries. Food Quality and Preference 22: 165–172. https://doi.org/10.1016/j.foodqual.2010.09.007. Arboleda, A.M. and Arce‐Lopera, C. (2017). The French, German, and Spanish sound of eating fresh fruits and vegetables. Food Research International 102: 171–175. https://doi. org/10.1016/j.foodres.2017.09.045. Ares, G., Jaeger, S.R., Antúnez, L. et al. (2015). Comparison of TCATA and TDS for dynamic sensory characterization of food products. Food Research International 78: 148–158. https://doi.org/10.1016/j.foodres.2015.10.023. Bourne, M.C. (1975). Is rheology enough for food texture measurement? Journal of Texture Studies 6: 259–262. https://doi.org/10.1111/j.1745‐4603.1975.tb01253.x. Bourne, M.C. (1978). Texture profile analysis. Food Technology 32 (7): 62–66, 72. Bourne, M.C. (2002). Food Texture and Viscosity, Concept and Measurement, 2nd edition. New York: Academic Press. https://www.elsevier.com/books/food‐texture‐and‐viscosity/ bourne/978‐0‐12‐119062‐0. Brandt, M.A., Skinner, L.Z., and Colcman, J.A. (1963). Texture profile method. Journal of Food Science 28: 404–409. https://doi.org/10.1111/j.1365‐2621.1963.tb00218.x. Bult, J.H.F., de Wijk, R.A., and Hummel, T. (2007). Investigations on multimodal sensory integration: texture, taste, and ortho‐ and retronasal olfactory stimuli in concert. Neuroscience Letters 411: 6–10. https://doi.org/10.1016/j.neulet.2006.09.036. Castura, J.C., Antúnez, L., Giménez, A. et al. (2016). Temporal check‐all‐that‐apply (TCATA): a novel dynamic method for characterizing products. Food Quality and Preference 47: 79–90. https://doi.org/10.1016/j.foodqual.2015.06.017. Chen, J. (2009). Food oral processing – a review. Food Hydrocolloids 23: 1–25. https://doi. org/10.1016/j.foodhyd.2007.11.013. Chen, J., Karlsson, C., and Povey, M. (2005). Acoustic envelope detector for crispness assessment of biscuits. Journal of Texture Studies 36: 139–156. http://doi.org/ 10.1111/j.1745‐4603.2005.00008.x. Chen, J. and Stokes, J.R. (2012). Rheology and tribology: two distinctive regimes of food texture sensation. Trends in Food Science & Technology 25: 4–12. https://doi. org/10.1016/j.tifs.2011.11.006. Cheong, J.N., Foster, K.D., Morgenstein, M.P. et al. (2014). The application of temporal dominance of sensations (TDS) for oral processing studies: an initial investigation. Journal of Texture Studies 45: 409–419. https://doi.org/10.1111/jtxs.12091. Cichero, J.A.Y. (2017). Unlocking opportunities in food design for infants, children, and the elderly: understanding milestones in chewing and swallowing across the lifespan for new innovations. Journal of Texture Studies 48: 271–279. https://doi.org/10.1111/ jtxs.12236. Cliff, M. and Heymann, H. (1993). Development and use of time‐intensity methodology for sensory evaluation: a review. Food Research International 26: 375–385. https://www. sciencedirect.com/science/article/pii/096399699390081S/pdf?md5=853505eecd3d7ab94 ed528c342c666ee&pid=1‐s2.0‐096399699390081S‐main.pdf. Dacremont, M. (1995). Spectral composition of eating sounds generated by crispy, crunchy and crackly foods. Journal of Texture Studies 26: 27–43. https://doi.org/10.111 1/j.1745‐4603.1995.tb00782.x.

­  References

Demattè, M.L., Pojer, N., Endrizzi, I. et al. (2014). Effect of the sound of the bite on apple perceived crispness and hardness. Food Quality and Preference 38: 58–64. https://doi. org/10.1016/j.foodqual.2014.05.009. Drake, B.K. (1963). Food crushing sounds: comparison of objective and subjective data. Journal of Food Science 28: 233–241. https://doi.org/10.1111/j.1365‐2621.1963. tb00190.x. Drake, B. (1989). Sensory textural/rheological properties—a polyglot list. Journal of Texture Studies 20: 1–27. https://doi.org/10.1111/j.1745‐4603.1989.tb00417.x. Fiszman, S. and Tarrega, A. (2018). The dynamics of texture perception of hard solid food: a review of the contribution of the temporal dominance of sensations technique. Journal of Texture Studies 49:202–212. https://doi.org/10.1111/jtxs.12273. Friedman, H.H., Whitney, J.E., and Szczesniak, A.S. (1963). The Texturometer—a new instrument for objective texture measurement. Journal of Food Science 28: 390–396. https://doi.org/10.1111/j.1365‐2621.1963.tb00216.x. Hayakawa, F. (2015). Vocabularies and terminologies of food texture description and characterization. In: Modifying Food Texture, vol. 2, 3–18. Elsevier. https://www. sciencedirect.com/science/article/pii/B9781782423348000018. Hayakawa, F., Ioku, K., Akuzawa, S. et al. (2005). Collection of Japanese texture terms (studies on Japanese texture terms part 1). Journal of the Japanese Society for Food Science and Technology (Nippon Shokuhin Kagaku Kogaku Kaishi) (in Japanese) 52: 337–346. https://doi.org/10.3136/nskkk.52.337. Hayakawa, F., Kazami, Y., Nishinari, K. et al. (2013). Classification of Japanese texture terms. Journal of Texture Studies 44: 140–159. https://doi.org/10.1111/jtxs.12006. Hutchings, J.B. and Lillford, P.J. (1988). The perception of food texture—the philosophy of the breakdown path. Journal of Texture Studies 19: 103–115. https://doi. org/10.1111/j.1745‐4603.1988.tb00928.x. ISO 11036 (1994). Sensory Analysis – Methodology – Texture Profile. Genève: International Organization for Standardization. Jack, F.R., Piggott, J.R., and Paterson, A. (1994). Analysis of textural changes in hard cheese during mastication by progressive profiling. Journal of Food Science 59: 539–543. https:// doi.org/10.1111/j.1365‐2621.1994.tb05557.x. Jeltema, M., Beckley, J., and Vahalik, J. (2015). Model for understanding consumer textural food choice. Food Science & Nutrition 3: 202–212. https://doi.org/10.1002/fsn3.205. Jowitt, R. (1974). The terminology of food texture. Journal of Texture Studies 5: 351–358. https://doi.org/10.1111/j.1745‐4603.1974.tb01441.x. Koç, H., Vinyard, C.J., Essick, G.K. et al. (2013). Food oral processing: conversion of food structure to textural perception. Annual Review of Food Science and Technology 4: 237–266. https://doi.org/10.1146/annurev‐food‐030212‐182637. Kohyama, K. (2015). Oral sensing of food properties. Journal of Texture Studies 46: 138–151. https://doi.org/10.1111/jtxs.12099. Kohyama, K. (2018). Supporting young researchers in food texture studies. Journal of Texture Studies 49:150–159. https://doi.org/10.1111/jtxs.12322. Labbe, D., Schlich, P., Pineau, N. et al. (2009). Temporal dominance of sensations and sensory profiling: a comparative study. Food Quality and Preference 20: 216–221. https:// doi.org/10.1016/j.foodqual.2008.10.001. Lazo, O., Claret, A., and Guerrero, L. (2016). A comparison of two methods for generating descriptive attributes with trained assessors: check‐all‐that‐apply (CATA) vs. free choice

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profiling (FCP). Journal of Sensory Studies 31: 163–176. https://doi.org/10.1111/ joss.12202. Le Révérend, F.M., Hidrio, C., Fernandes, A. et al. (2008). Comparison between temporal dominance of sensations and time intensity results. Food Quality and Preference 19: 174–178. https://doi.org/10.1016/j.foodqual.2007.06.012. Lee, W.E. III and Pangborn, R.M. (1986). Time‐intensity: the temporal aspects of sensory perception. Food Technology 40 (1): 71–78. Lillford, P. (2018). Texture and breakdown in the mouth: an industrial research approach. Journal of Texture Studies 49:213–218. https://doi.org/10.1111/jtxs.12279. Nishinari, K. and Fang, Y. (2018). Perception and measurement of food texture—solid foods. Journal of Texture Studies 49:160–201. https://doi.org/10.1111/jtxs.12327. Nishinari, K., Hayakawa, F., Xia, C. et al. (2008). Comparative study of texture terms: English, French, Japanese and Chinese. Journal of Texture Studies 39: 530–568. https:// doi.org/10.1111/j.1745‐4603.2008.00157.x. Nishinari, K., Kohyama, K., Kumagai, H. et al. (2013). Parameters of texture profile analysis. Food Science and Technology Research 19: 519–521. https://doi.org/10.3136/fstr.19.519. Peruzzini, M., Mengoni, M., and Germani, M. (2012). Virtual tactile simulation: a novel display and the effects on users’ texture perception. ASME/ISCIE 2012 International Symposium on Flexible Automation, ISFA 2012, 671–678. St. Louis, MO, USA (18–20 June 2012). New York, USA: American Society of Mechanical Engineers. http://dx.doi. org/10.1115/ISFA2012‐7191. Peyron, M.A., Woda, A., Bourdiol, P. et al. (2017). Age‐related changes in mastication. Journal of Oral Rehabilitation 44: 299–312. https://doi.org/10.1111/joor.12478. Pineau, N., Schlich, P., Cordelle, S. et al. (2009). Temporal dominance of sensations: construction of the TDS curves and comparison with time‐intensity. Food Quality and Preference 20: 450–455. https://doi.org/10.1016/j.foodqual.2009.04.005. Rosenthal, A.J. (1999). Relation between instrumental and sensory measures of food texture. In: Food Texture: Measurement and Perception, 1–17. Aspen http://www. springer.com/us/book/9780834212381. Scott‐Blair, G.W. (1958). Rheology in food research. Advances in Food Research 8: 1–61. https://doi.org/10.1016/S0065‐2628(08)60017‐8. Shama, F. and Sherman, P. (1973). Identification of stimuli controlling the sensory evaluation of viscosity. II. Oral methods. Journal of Texture Studies 4: 111–118. https:// doi.org/10.1111/j.1745‐4603.1973.tb00657.x. Sherman, P. (1969). Texture profile of foodstuffs based upon well‐defined rheological properties. Journal of Food Science 34: 458–462. https://doi.org/10.1111/j.1365‐ 2621.1969.tb12804.x. Shiozawa, K., Kohyama, K., and Yanagisawa, K. (1999). Food bolus texture and tongue activity just before swallowing in human mastication. Japanese Journal of Oral Biology 41: 297–302. https://doi.org/10.2330/joralbiosci1965.41.297. Sprunt, J.C., Raithatha, C.E., and Smith, A.C. (2002). Swallow indicator methodology as an enhancement to combined time‐intensity measurement of flavour release and electromyography for monitoring mastication. Food Quality and Preference 13: 47–55. https://doi.org/10.1016/S0950‐3293(01)00056–8. Stokes, J.R., Boehm, M.W., and Baier, S.K. (2013). Oral processing, texture and mouthfeel: from rheology to tribology and beyond. Current Opinion in Colloid & Interface Science 18: 349–359. https://doi.org/10.1016/j.cocis.2013.04.010.

­  References

Stone, H., Sidel, J., Oliver, S. et al. (1974). Sensory evaluation by quantitative descriptive analysis. Food Technology 28 (11): 24, 26, 28, 29, 32, 34. Szczesniak, A.S. (1968). Correlations between objective and sensory texture measurements. Food Technology 22: 981–985. Szczesniak, A.S. (2002). Texture is a sensory property. Food Quality and Preference 13: 215–225. https://doi.org/10.1016/S0950‐3293(01)00039‐8. Szczesniak, A.S. and Bourne, M.C. (1969). Sensory evaluation of food firmness. Journal of Texture Studies 1: 52–64. https://doi.org/10.1111/j.1745‐4603.1969.tb00956.x. Taniwaki, M. and Kohyama, K. (2012). Mechanical and acoustic evaluation of potato chip crispness using a versatile texture analyzer. Journal of Food Engineering 112: 268–273. https://doi.org/10.1016/j.foodeng.2012.05.015. Tunick, M.H. (2011). Food texture analysis in the 21st century. Journal of Agricultural and Food Chemistry 59: 1477–1480. https://doi.org/10.1021/jf1021994. Ung, C.‐Y., Menozzi, M., Hartmann, C. et al. (2018). Innovations in consumer research: the virtual food buffet. Food Quality and Preference 63: 12–17. https://doi.org/10.1016/j. foodqual.2017.07.007. United Nations (2015). Transforming our world: the 2030 agenda for sustainable development. General Assembly. A/70/L.1. http://www.un.org/ga/search/view_doc. asp?symbol=A/70/L.1. Verhagen, J.V. and Engelen, L. (2006). The neurocognitive bases of human multimodal food perception: sensory integration. Neuroscience and Biobehavioral Reviews 30: 613–650. https://doi.org/10.1016/j.neubiorev.2005.11.003. Vickers, Z.M. (1984). Crispness and crunchiness—a difference in pitch. Journal of Texture Studies 15: 157–163. https://doi.org/10.1111/j.1745‐4603.1984.tb00375.x. Vickers, Z.M. and Bourne, M.C. (1976). Crispness in foods – a review. Journal of Food Science 41: 1153–1157. https://doi.org/10.1111/j.1365‐2621.1976.tb14406.x. Wilkinson, C., Dijksterhuis, G.B., and Minekus, M. (2000). From food structure to texture. Trends Food Science & Technology 11: 442–450. https://doi.org/10.1016/S0924‐2244(01) 00033‐4. Yoshikawa, S., Nishimaru, S., Tashiro, T. et al. (1970). Collection and classification of words for description of food texture. I: collection of words. Journal of Texture Studies 1: 437–442. https://doi.org/10.1111/j.1745‐4603.1970.tb00742.x. Zampini, M. and Spence, C. (2004). The role of auditory cues in modulating the perceived crispness and staleness of potato chips. Journal of Sensory Studies 19: 347–363. https:// doi.org/10.1111/j.1745‐459x.2004.080403.x. Zampini, M. and Spence, C. (2005). Modifying the multisensory perception of a carbonated beverage using auditory cues. Food Quality and Preference 16: 632–641. https://doi.org/10.1016/j.foodqual.2004.11.004.

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Part I North America

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2 Food Textures in the United States of America Alina Surmacka Szczesniak Mount Vernon, New York, USA

2.1 ­Introduction Research on various aspects of food texture conducted in the United States can be traced back almost 100 years. Meat and baked goods received the earliest attention, followed by fruits and vegetables. The work was motivated by economic reasons more than by pure scientific curiosity. Tough meat, stale bread that tastes dry and hard, fibrous vegetables, and fruit lacking juiciness are unacceptable to the consumer except in times of starvation and dire need. Thus, experience pointed to the effect of texture on consumer acceptance of food products. However, because of fragmentation of the early texture research according to commodity types, it was not until the 1960s that general and more focused knowledge began to be generated on the role of texture in shaping consumer attitudes – to foods and in influencing food quality. Using scientific methods it was demonstrated that texture is a recognizable food attribute and that, in certain foods, it is even more important than flavor in affecting their acceptance and preference (Szczesniak and Kahn 1971). Above all, it was shown that, just like flavor, texture is a multifaceted attribute composed of a number of different notes (Szczesniak 1963).

2.2 ­Texture and the American Consumer For a long time, flavor was considered to be the number‐one sensory attribute affecting food acceptance. However, the aforementioned consumer studies revealed that texture is indeed a significant factor in affecting food acceptance and preferences and that its universally accepted subservient status could be explained by consumers’ inability to verbalize their attitudes to and specific feelings about textural attributes. The studies found that when supplied with specific words to describe texture, the consumers were able to express strong feelings about the connotations of different textural characteristics and factors that govern their acceptability.

Textural Characteristics of World Foods, First Edition. Edited by Katsuyoshi Nishinari. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

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The studies also showed that texture becomes most important when the flavor intensity is low (e.g. with lettuce, cucumbers, bread), or when the textural characteristics are very appealing and well defined (e.g. crisp, crunchy). It was also demonstrated that teenagers are more texture conscious than mature adults. Although no recent extensive consumer studies were conducted to supplement the early work, there are many observations and indications that texture should no longer be called “a forgotten food attribute” (Szczesniak 1990) It is recognized as a salable characteristic indicative of high food quality demanded by consumers. It can be used to support product image and provide important product differentiation increasing its sales over competition.

2.3 ­Role of Texture in Food Quality and Acceptance The role of texture in food quality takes two forms: absence of characteristics with a negative effect on quality, and presence of liked characteristics with a positive effect on quality (Szczesniak 1991). The former, absence of defects, is always of primary concern to food growers, processors, and marketers. The latter, presence of favored attributes, is of great significance in developed countries with consumer‐oriented markets and keen competition. Consumer equate good texture with high‐quality food and excellence of cooking. They also equate it with freshness (e.g. crisp vs. flabby vegetables), health, and good nutrition (e.g. tender, good‐quality meats).

2.4 ­Factors Shaping Attitudes to and Acceptance of Texture Factors that form attitudes to texture can be divided into those that are common to all peoples and those that are culturally specific (Szczesniak and Kahn 1971). Extremely important are physiological factors that refer to the ability of the consumer to handle the food during consumption. People want to be in full control of the food in their mouth and feel that textures that are not easily manageable can cause discomfort, choking, and gagging. Crisp, chewy foods/can be grasped firmly with the teeth, chewed into small bits, and swallowed with ease. Stringy foods can catch in the teeth and throat, while sticky foods will adhere to the tongue, gums, and palate, causing unpleasant situations that often lead to social embarrassment. People also want to be in full control of the food on the plate and will reject items difficult to cut and manipulate with eating utensils. One notable exception is consumption of whole, raw oysters. Slimy and slippery, they are not chewed in the mouth but are allowed to slide down the throat in an almost uncontrollable manner. This is an acquired custom (incomprehensible to many, including this author) spurred by a snobbish desire of some people to belong to a “gourmet elite.” Another set of physiological factors affecting texture acceptance is the limited strength of our teeth and jaws (modern humans do not chew bones!) and the proneness to injury by sharp objects of the soft tissue in our mouth.

2.4  Factors Shaping Attitudes to and Acceptance of Texture

Socially and culturally learned expectations condition people with regard to food and food characteristics early in their lives. A growing child learns to associate certain ­textures with certain foods and develops a set of rules on what proper textures should be. He or she also learns under parental guidance to distinguish between textures of inedible materials (e.g. sticks and stones) and textures of edible food products. The developed rules will be highly influenced by the culture to which the child belongs. In traditional American culture, mashed potatoes are expected to be smooth and free of lumps, bread to be soft, tender, and finely grained, and meat to be tender and juicy. However, these rules are often modified as people come in contact and becoming ­familiar with other cultures. Within this group of factors is also the connotation of “food for us” and “food for them.” Economic and social hierarchy within a society and segmentation due to specific experiences (e.g. lack of financial resources due to unemployment) cause this difference in food habits, which has implications to attitudes to specific textures. In early America, the light, airy, fluffy, tender, creamy textures were the domain of the privileged class, while chewy, tough, hard textures were associated with food of the working class. For many years after the Great Depression, certain types of inexpensive processed meat (e.g. bologna) were associated with financial hardship and considered not fit to eat by financially comfortable individuals. Psychological factors are also (very) important in the development of feelings and attitudes about texture. People make associations between textural characteristics of foods and certain events in their life, be they positive or negative. The most obvious, usually positive, association is the connection between softness, smoothness, and creaminess of baby food and love and nurturance. Such textures are then valued in adult life in times of illnesses and by people needing a psychological/emotional boost. Dry toast, or certain types of cold cereals, often trigger a negative association with deprivation and punishment suffered in childhood. Sometimes associations are made with nonfood materials (e.g. hay, slime). These unquestionably lead to rejection of the food due to unpleasant texture. Violation of expectations is another factor affecting acceptance of texture. It stems from two principles: (i) that our process of food consumption starts with visual inspection, and (ii) that in assessing the food we bring to bear our past experiences. Thus, the food texture must not violate expectations triggered in the consumer’s mind based on the visual examination of the food combined with past experience. A piece of candy (e.g. toffee) that “looks” soft will be rejected if it turns out to feel hard in the mouth. Textural contrast (which will be treated more fully later) must be visible to the eye. The consumer should not be caught by surprise in finding hard nut pieces in a pudding that, based on experience and visual impression, should be uniformly smooth and creamy. In the United States, eating occasions, especially those dictated by the time of day, were found to have a strong influence on attitudes toward and preferences for specific textures. The range of acceptable textures appears to be most limited at breakfast and widens as the day progresses. In the morning, the preferred textures and flavors are those that are familiar (largely determined by the culture) rather than new, and passive rather than aggressive or challenging. Especially liked are those foods that lubricate the mouth, can be swallowed and digested with ease, and require little effort in controlling and manipulating in the mouth.

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As the day progresses, acceptance of characteristics associated with wholesomeness declines and that of characteristics associated with enjoyment rises. The evening dinner is the meal at which texture is most appreciated and enjoyed. Texture tolerance and willingness to try new foods are higher, and the meal often includes several foods with varying texture. If the texture of one food item leads to its rejection, the consumer can always look forward to another course to satisfy hunger. Both textures and flavors preferred for dinner are “aggressive.” The preferred textures are those that require more energy for mastication and the preferred flavors are more heavily seasoned and definite. These remarks refer mainly, but not exclusively, to old‐fashioned family dinners, be they consumed at home or in a restaurant. With both parents often working, the traditional family dinners in the United States are frequently being replaced with take‐out food, and grazing is taking the place of the traditional three meals a day. True texture preferences appear to be giving way to “anything goes” – provided, of course, that the basic requirements imposed by physiological, psychological, and social factors are met. The image a product is intended to convey has a strong influence on what texture it should have. Foods intended to project the image of being nutritious and pampering should, in general, be soft, creamy, substantial, and filling. Those conveying the image of activity and fun should be crisp and bitey.

2.5 ­Liked and Disliked Textural Characteristics High on the list of liked textural characteristics are crispness and crunchiness (Table 2.1). Their appeal is not limited to the US consumer but seems to be universal throughout the world. They are especially appreciated in Japanese and Chinese cultures, where a large number of onomatopoeic words are used to describe these sensations (Yoshikawa et al. 1970; Szczesniak 1988), in contrast to only a few in the English language. A “crisp” food, for example, is one that is firm and snaps (breaks) easily and cleanly, with the break being accompanied by the release of a sharp characteristic sound. A “crunchy” food is one that exhibits a series of consecutive breaks upon biting and gives Table 2.1  Typical liked and disliked textural characteristics. Liked

Disliked

crispness

sogginess

crunchiness

toughness

tenderness

sliminess

juiciness

crumbliness

firmness

gumminess

smoothness

stickiness

creaminess

gooiness

chewiness

dryness slipperiness

2.5  Liked and Disliked Textural Characteristics

Table 2.2  Popular crisp foods in the United States. dry/crisp

wet/crisp

crackers

lettuce

potato chips

celery

bacon

apple

toast

radishes

skin of fried chicken

green peppers

cookies

pickles

pretzels com chips hard rolls crusty bread Source: Adapted from Szczesniak (1988).

rise to a sequential release of characteristic sounds (similar to those produced by stepping on icy snow). These textural characteristics have many positive connotations. Their presence signifies freshness and high food quality. They are a stimulant to active eating and in the United States are often consumed as an accompaniment to sedentary activities, such as watching TV or reading. In the American culture, munching on crisp popcorn while watching a movie is a “must” for many consumers, often to the annoyance of other people in the theater. As shown in Table  2.2, there are two categories of crisp foods: those that are dry (generally 85% water) (Vickers and Bourne 1976; Szczesniak 1988). Crispness in dry products is generally produced by one of two process types: frying (usually deep‐fat frying) or baking. In both cases, moisture is removed from the food and a rheologically brittle structure is formed. The wet/crisp category of products is comprised of mostly specific fresh, raw fruits, and vegetables. In this case, crispness is caused by the turgor, i.e. intracellular pressure, which keeps the cellular network rigid and extended, and (as is also the case with dry/crisp products) rheologically brittle structure. Refrigerated pickles are an example of a processed (albeit minimally) wet/crisp product and one that owes its marketing success to the appealing crunchy texture. Crispness is maintained in dry/crisp products by preventing them from absorbing moisture. In wet/crisp products, crispness is maintained by preventing them from losing moisture and by slowing the onset of senescence. Commercially sold cucumbers are coated with wax to prevent desiccation. Apples are kept in controlled storage to slow down their metabolism and reduce moisture loss. The opposite of crispness/crunchiness is sogginess and flaccidity, both undesirable characteristics. Tenderness is a widely accepted indicator of quality and, in addition, is linked in the consumer’s mind with good nutrition. It is associated with good‐quality meat, young, vegetables (such as peas and corn) and cakes. Its absence will usually mean the presence of toughness, an undesirable characteristic. A tender product is one that needs

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only a limited amount of chewing for disintegration. In meat, tenderness is associated with high fracturability of meat fibers and low level of connective tissue. In young vegetables, tenderness is due to the presence of sugars that have not yet converted to starch (as in mature vegetables) and absence of toughness‐imparting cellulose fibers. In cakes, a tender texture is developed based on judicial selection of ingredients and their expert manipulation. It is associated with “lightness” and an open structure of small air cells. Juiciness is another highly liked textural characteristic, one that seems appetizing and appealing in itself. It wets and refreshes the mouth and its absence violates expectations and lowers the perceived quality. Just like tenderness and crispness, it has both hedonic and economic aspects. In the United States, the term juicy is usually used in relation to meat and fruit, while the term succulent is usually used in reference to young vegetables that contain significant amounts of expressable juice. Here, the terms juicy and juiciness are used in an all‐encompassing meaning. In the general sense, juice is the liquid expressed from a food product on mastication. The following factors appear to be needed for fruits and vegetables to be juicy: high water content, organized cellular network with proper turgor and integrity, cell walls mechanically weaker than the middle lamella (so that on biting the break in the tissue occurs across and not in between the cell walls), low viscosity, and little suspended solids in the expressed liquid. Juiciness increases with increasing cell size and decreasing cell wall thickness (Szczesniak and Ilker 1988). The release of juice from the product should be such as not to violate good table manners and to enable the consumer to contain it easily in the mouth. In contrast to food products of plant origin in which the juice is composed primarily of water, juiciness in meats is derived from a mixture of expressible water and liquid fat. It is influenced by the characteristics of raw meat and the manner of cooking. Greater marbling in raw meat and searing (i.e. application of intense heat to the surfaces of raw meat) as the first step in cooking will increase juiciness. Searing forms a crust difficult for water to penetrate, thus “sealing in the juices.” Firmness is often named by consumers as the ideal texture for many prepared foods. It describes products that do not “fall apart” but are readily disintegrated by biting and chewing. Hardness, which is intensified firmness, has a negative connotation unless it is transitory. Its opposite, softness, is also negative when used exclusively in the diet, but in many products is considered a positive quality. There appears to be a polarity between hardness, which is active, and softness, which is passive. This polarity has several connotations in the consumer’s mind, including that of softness being linked with infant food and hardness/crispness being linked with adult food. Crispness is tooth‐oriented, while softness is stomach‐oriented. With excess crispness one simply turns away when satiety is reached. Too much softness, on the other hand, can cause the uncomfortable feelings of nausea and excessive fullness. Textural characteristics listed as “disliked” in Table 2.1 will not be discussed in detail. It should be mentioned, however, that some of them may be quite acceptable in special situations. For example, gooiness may be a liked feature in certain types of desserts, i.e. an indulgence food that comes at the end of a meal and whose consumption is not necessary for curbing hunger.

2.7  Contemporary Trends

2.6 ­Textural Contrast Children prefer simple, one‐dimensional textures. As life processes progress and the different senses require more varied stimulation, preference shifts to textural contrast, which, with adults, becomes a highly valued food attribute. There are four general classes of texture contrast: (i) within a meal, (ii) on the plate, (iii) within a multiphase food, and (iv) within a uniphased food during consumption (Szczesniak and Kahn 1984). Of these, multiphase foods are of particular interest to food marketers. Typical examples in the American market are filled cookies, pies, and chocolate candies, to name just a few. A typical apple pie will have a crisp crust and a thick, smooth filling, with firm, juicy apple pieces. An additional texture contrast may be provided by the housewife in the form of a whipped cream‐type topping. A popular cookie (Oreo) contains a white, smooth, sweet filling between two baked, black, crisp, chocolate‐flavored layers. This, additionally provides color and flavor contrasts. Chocolate bars with smooth, creamy centers or crunchy nut inlays make for popular and interesting snacks. Several fundamental principles seem to govern the acceptance of texture contrast. Optimal texture and combinations are challenging and pleasurable. Too many textures in combination, however, should be avoided. Pleasant texture combinations involve either strong differentiation (e.g. crisp and creamy) or closely related characteristic (e.g. soft and creamy). Texture combinations should be anticipated and should not catch the consumer by surprise. They require some stability and integrity, i.e. they should not coalesce too quickly into a single texture sensation on storage and handling, or in the mouth. They should not be difficult or messy to eat, and should leave the mouth feeling clean and comfortable. The same principles apply to uniphased products that develop textural contrast on eating. Ice cream, gelatin desserts and chocolate are examples of such products. They change from a solid to a liquid in the mouth due to the warm body temperature. In the provided examples, this is done by melting ice crystals, melting gel network and melting fat, respectively. Such products are fun to eat and are used as desserts, snacks, and treats. Similarly to crispness, they spur the consumer to further eating. The change from a solid to a liquid is very pleasing and in line with the key principle of texture acceptance, i.e. that the resistance of the product must decrease on chewing and manipulation in the mouth. The quick phase change in the mouth is accompanied by a cooling effect, which adds to the enjoyment provided by the eating process.

2.7 ­Contemporary Trends The US population is composed of many groups representing different cultures, religions, ethnic backgrounds, and food habits. The once prevailing idea of a “melting pot,” where all these groups were expected to discard their differences and become a unified nation, has given way to the notion that diversity is valuable and enriching, and should be fostered. These groups brought their food habits to mainstream America by opening ethnic restaurants and introducing ethnic foods to supermarkets. Initially aimed at consumers from their own ethnic groups, many of these foods have now become integral parts of contemporary American diet.

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This trend started some generations ago, but has recently gained storm‐like forces. Many decades ago, people of Italian origin brought to America pasta and pizza. Italian names such as “Ronzoni” and “Giorgio” identified popular brands of dry pasta of different types. The contemporary trend toward fresh, refrigerated forms of pasta has increased their quality with respect to both flavor and texture. Catering to the more affluent (the difference in price is quite significant) these products exhibit firmer, more chewy textures with greater integrity. Pizza, liked for its crisp, chewy crust and textural contrast provided by the topping, is an extremely popular food product that can be used as a snack or a full meal. The home‐delivery system of the pizzerias has made pizza the most popular take‐out food. Competing for the first place in the home‐delivery system are Chinese restaurants. Their great food varieties with distinct and often unusual textures have made an important contribution to widening the American texture experience, especially with respect to different form of crispness and chewiness. This influence converged with changes in the lifestyle of the American consumer. Greater emphasis placed on physical fitness and health‐related factors have contributed to a shift from the mushy/ overcooked to the crisp/undercooked vegetables and from soft, cohesive white bread to the firm, grainy, and less‐cohesive whole wheat or pumpernickel bread (Munoz and Civille 1987). Other examples of ethnic foods with different, novel textures that have been well accepted into the American diet are croissants (crisp and flaky French pastry), bagels (chewy and cohesive baked product of Jewish origin used similarly to rolls and particularly appreciated with the smooth, creamy, somewhat sticky texture of cream cheese), tacos (South American unleavened cornmeal bread‐like staple), and salsa (highly spiced Mexican dip primarily made with tomatoes and peppers). Increased travel abroad introduced Americans to different food habits, a familiarity which they brought back home. In larger American cities, a person can now choose from a wide variety of ethnic restaurants unheard of a decade ago (Indian, Vietnamese Pakistani, Mexican, Thai, Indonesian, Scandinavian, etc.), in addition to the previously well‐established French, German, Italian, Japanese, and Chinese restaurants. Contributing to the infusion of American food habits with novel ethnic products is acquisition by large American food companies of small ethnic firms and the application of their financial muscle and marketing expertise to facilitate and speed up the entry of ethnic foods into the main markets through heavy and expensive advertising. The aging population is an important factor that may influence texture acceptance and preference of the American consumer in the future. It is only recently that some studies have been initiated in this regard and important guidelines may develop in the future. In the absence of hard data, opinions are currently divided on what foods and textures are suitable for old persons. Some people feel that, except perhaps for some different nutritional requirements, foods for old people should not differ from those for younger people. Other people argue that poor dentition, difficulties in swallowing, and decreased saliva production among the aging population might translate into needs for foods with different texture (and perhaps flavor) properties. Such foods may find more ready and easier markets in nursing homes than in households of independently living seniors. The development of such foods may represent a challenge for food technologists and an opportunity for the business world.

­  References

­References Munoz, A.M. and Civille, G.V. (1987). Factors affecting perception and acceptance of food texture by American consumers. Food Rev. Int. 3: 285–399. Szczesniak, A.S. (1963). Classification of textural characteristics. J. Food Sci. 28: 385–389. Szczesniak, A.S. (1971). Consumer awareness of texture and of other food attributes II. J. Texture Stud. 2: 196–206. Szczesniak, A.S. (1988). The meaning of textural characteristics – crispness. J. Texture Stud. 19: 51–59. Szczesniak, A.S. (1990). Texture: is it still an overlooked food attribute? Food Technol. 44 (9): 86–90. 92,95. Szczesniak, A.S. (1991). Textural perceptions and food quality. J. Food Qual. 14: 75–85. Szczesniak, A.S. and Ilker, R. (1988). The meaning of textural characteristics – juiciness in plant foodstuffs. J. Texture Stud. 18: 61–78. Szczesniak, A.S. and Kahn, E. (1971). Consumer awareness of and attitudes to food texture. I. Adults. J. Texture Stud. 2: 280–295. Szczesniak, A.S. and Kahn, E. (1984). Texture contrasts and combinations: a valued consumer attribute. J. Texture Stud. 15: 285–301. Vickers, Z. and Bourne, M.C. (1976). Crispness in foods – a review. J. Food Sci. 41: 1153–1157. Yoshikawa, S., Nishimaru, S., Tashiro, T., and Yoshida, M. (1970). Collection and classification of words for description of food texture I, collection of words. J. Texture Stud. 1: 437–442.

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3 Texture Characteristics of US Foods Pioneers, Protocols, and Attributes ‐ Tribute to Alina Gail Vance Civille, Amy Trail, Annlyse Retiveau Krogmann, and Ellen Thomas Sensory Spectrum, Inc., New Providence, New Jersey, USA

Alina Surmaka Szczesniak was a wonderful scientist and an inspiration. As the Mother of Food Rheology, Alina set out to, and succeeded in, changing the way food scientists measure the texture of food. Up until her work, separate measures were made within each food type (bread, peas, ketchup, etc). The unified approach of the General Foods Texture Profile Method allowed for texture measurements across food types based on both rheological and sensory principles (Brandt et  al. 1963; Szczesniak 1975; Muñoz et al. 1992). Often, I heard Alina declare: Texture is a sensory property and can only be measured by humans; instruments can only simulate the human experience (Szczesniak 2002). From Alina I learned that instrumental measures can only be valid if they measure the attribute the human is perceiving using an instrument that mimics the type, direction, and rate of force application used in the mouth or in the hand (Szczesniak 1963). Thus, it is possible that instruments fail to measure the “texture” as the human perceives it. Alina taught discipline and scientific rigor – she was a great mentor, teacher, and friend. Inspired by Alina’s inspiration and scientific rigor, the Spectrum Descriptive Analysis method (Meilgaard et al. 2016; Dus et al. 2018) adheres to strict guidelines for developing the protocols for preparation of samples, and for the development of lexicons (Szczesniak 1963; Civille and Lawless 1997; ASTM Stock #DS72 2011; Lawless and Civille 2013) and rating scales (Szczesniak et al. 1963; Muñoz and Civille 1998) for sample evaluation.

3.1 ­The Protocols for Developing a Texture Lexicon To ensure consistency and reliability of sensory texture data, four aspects of the descriptive analysis process should be controlled/regulated (see Table 3.1): 1) Attributes – the descriptors in the lexicon; must be clearly defined 2) Scales – to indicate the intensity of the attribute; must be calibrated

Textural Characteristics of World Foods, First Edition. Edited by Katsuyoshi Nishinari. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

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3  Texture Characteristics of US Foods

Table 3.1  Definitions for food attributes. Definitions For Solid Food Attributes

Manual/surface stage Manual oiliness

The amount of oil perceived on the fingers after manipulation [none to large amount]

First bite/first chew stage Force to pull

The amount of force needed to break the sample when held between the front teeth and pulled outward with the dominant hand (no force to large amount of force). The procedure is to place and hold the end of a strip of bacon in the front teeth while grasping the bacon between two fingers toward the other end of the strip. To measure the force – pull on the strip with the fingers until it breaks into two pieces. You are measuring the force it takes to pull the bacon apart into two pieces.

Hardness

The force required to bite through the sample using the molars. (low force/soft to high force/hard)

Force to grind

The force required to break through the sample by grinding the teeth after biting/chewing through to the “skin” or fiber (none to large amount)

Fracturability

The force with which the sample ruptures when placing the sample between the molars and biting down at an even rate. (crumbles to fractures)

Crispiness

The force with which a product breaks or fractures (rather than deforms) when the product is chewed with the molar teeth, characterized by many small breaks. [not crisp to very crisp]

Crunchiness

The force with which a product breaks or fractures (rather than deforms) when a product is chewed with the molar teeth, characterized by few, large breaks. (not crunchy to very crunchy)

Cohesiveness

The amount the sample deforms rather than crumbles, cracks, or breaks (ruptures to deforms)

Denseness

The compactness of the cross section of the sample while biting completely through with the molars. (airy to dense/compact)

Flinty

The degree to which the product shards into sharp slivers during the bite down, similar to a hard peppermint stick candy

Chewdown stage Persistence of Crisp/ crunch

The duration the sample remains crispy/crunchy during mastication

Cohesiveness of mass

The degree to which the sample holds together in a mass (loose to tight)

Moisture Absorption

The amount of moisture the product absorbs during chewdown (no absorption to high absorption)

Moistness of mass

The amount of wetness/oiliness/moisture on the surface of the chewed mass (dry mass to moist mass)

Roughness of mass

The degree to which the mass feels rough/abrasive (smooth to rough)

Fibrous between teeth

The amount of grinding of fibers to get through the sample (none to large amount)

Number of chews to Swallow

The number of chews required to swallow the sample

3.1  The Protocols for Developing a Texture Lexicon

Table 3.1  (Continued) Definitions For Solid Food Attributes

Residual stage Oily film

The amount of oily film left on the mouth surfaces [none to large amount]

Oily/greasy mouthcoating

The amount of oily and greasy residue felt by the tongue when moved over the surfaces of the mouth (none to high)

Loose particles

The amount of particles remaining in the mouth after expectoration (none to large amount)

Definitions for semi‐solid attributes

Manual/surface stage Manual Oiliness

The amount of oil perceived on the fingers after manipulation (none to large amount]

First compression stage Semi‐solid Firmness

The force required to compress the sample between tongue and palate (low force to high force)

Semi‐solid Cohesiveness

The amount the sample deforms rather than cuts/shears (deforms to cuts/ shears)

Semi‐solid Slipperiness

The ease to slide the tongue over the product. (drag to slip)

Chewdown/manipulation stage Adhesiveness to Palate

The force required to remove the sample from the palate with the tongue (low force to high force)

Semi‐solid Mixes with Saliva

The degree to which the mass mixes with the saliva (no mixing to uniform mixing)

Roughness of Mass

The degree to which the mass feels rough/abrasive (smooth to rough)

Residual stage Oily film

The amount of oily film left on the mouth surfaces (none to large amount)

Residual Mouthcoating

The amount of film felt by the tongue when moved over the surfaces of the mouth. (None to large amount)

3) Procedures for evaluation – how to manipulate the product; must be defined 4) Protocols for sample preparation – how to make and serve the sample; must be consistent and realistic to how the food is normally prepared and consumed These principles are applied in this chapter to three food products commonly consumed in the United States. They demonstrate how to develop texture lexicons and the necessary protocols for preparation and evaluation. The use of highly trained panels (Civille and Szczesniak 1973) and sound procedures can then be used to aid in product design and optimization (Civille and Seltsam 2014).

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3.2 ­Texture Profiles and Evaluation Protocols for Selected US Foods Three foods were selected to represent uniquely different food texture experiences and also to define an important US food preference. Included in this chapter are an example of how to prepare the food for texture evaluation, an example texture ballot, and an explanation of a few of the texture attribute protocols. Potato chips are truly American. They are an important side for hamburgers and sandwiches, in addition to being a solo snacking experience often enjoyed plain or with dips. Potato chips offer a fried, salty flavor experience. However, when asked why they love potato chips, consumers say the main reason is the texture  –  light, crispy, and sometimes crunchy. When evaluating potato chips for texture, one of the primary concerns is timing of the preparation with serving. Potato chips begin to change immediately when exposed to air  –  losing some of the crispy and crunchy intensity due to moisture absorption. The other thing considered while evaluating potato chips is the technique on how to bite the chip. This is controlled through training best practices and texture attribute protocols. Bacon is another fried, salty flavor experience that is very popular in the United States. It has a very different texture experience than potato chips. Bacon has been a part of the American diet for centuries because salt‐cured pork is a very stable protein source. In recent years, it seems that bacon has become even more popular than just a normal side breakfast offering and can now be found in sandwiches, burgers, salads, and even chocolate. Bacon has evolved into being its own food group in consumers’ minds. The texture experience of bacon does include crispy and crunchy, but the chewy and fibrous aspects are also really important. The protocols around preparing bacon for evaluation heavily focus on how it is prepared, so that it is cooked fully to create the crunchy and chewy experience. A challenge in bacon evaluation comes with the ratio of lean protein to fat in a strip  –  that ratio will change the texture attribute intensities, and even within a batch will lead to piece‐to‐piece variation. Protocols are put into place during a texture evaluation to make sure this variation is part of the story. Peanut butter is a nut butter (actually, roasted legume) that is more common in the United States than other countries. A very popular protein source for sandwiches, it is also used in desserts and spreads, or simply eaten with a spoon right from the jar. The traditional texture is a very smooth peanut butter spread that contains sweeteners and solid fats to enhance the lubricity (though this spread is also sold as a chunky version with added peanut pieces). Lately, the market has also expanded to include a number of natural peanut butter products, with focus on what the industry would call a peanut paste product that limits the amount of extra sugars and fats added to the final product. The natural peanut butters are firmer and not as smooth as a peanut butter spread product. Texture evaluations of peanut butters use a semi‐solid evaluation technique that includes a different set of scales and references for descriptive evaluation that those used for the evaluation of solid foods such as bacon or potato chips. Protocols focus on amount of product placed in the mouth, how to move the sample around, and how to clear the mouth in between evaluations.

3.3  Potato Chip Texture Example

3.3 ­Potato Chip Texture Example 3.3.1  Serving Protocol Chip samples need to be dished within 30 minutes of the tasting evaluation. If the tasting environment has high humidity, chips should be dished as close to evaluation as possible. Sort chips to remove any broken pieces – serve only whole chips. Use visual examination of the chip batch to sort and eliminate any visual abnormalities such as green or brown edges and/or brown or black spots. Also remove any fold‐over or double chips (stacked/fried) if they are in the minority. Only remove these chips if they are a minority of the sample ( G″ the material shows an elastic behavior that is ­associated with the stored energy that can be recovered (Steffe 1996). In general, a  ­viscoelastic material behaves in a solid‐like manner at high frequencies when the ­viscoelastic moduli are considered as a function of frequency (Ferry 1980). In the commercial doughs containing gluten, the storage modulus G′ was always higher than the loss modulus G″ within the experimental frequency range, although in the low‐frequency regime both curves (G′ and G″) come closer. This behavior could yield to a crossover point for frequencies lower than 10−2 rad/s indicating that the ­recovery of the stressed dough network was a slow process and the network was not completely elastic. According to Tolstoguzov (1997), the revolving of starch granules during the handling of gluten‐containing dough can decrease the friction between adjacent gluten layers flowing at different rates. The ball‐bearing effect results in unusually high dough fluidity in spite of the fact that wheat flour dough is one of the most concentrated food ­systems. In flowing dough, the granules rotating between adjacent gluten layers could roll out the gluten strips. Starch granule size, much as a rolling pin, exceeds the gluten strip thickness. This rolling‐pin effect could greatly contribute to dough structure. For example, it could be responsible for the homogeneous three‐dimensional structure of bakery goods. Dough mixing leads to the formation of a concentrated gluten phase and the development of noncovalent interactions, mainly hydrophobic interactions, between polypeptide chains oriented in shear flow. A decrease in the mobility of macromolecular chains resulting from hydrophobic and hydrogen bonding within the aggregates can be compensated by liberation of water molecules from hydrated nonpolar groups of the unfolded polypeptide chains. Lipids can plasticize highly hydrophobic gluten proteins in low‐moisture doughs. Another effect may be a reduction in the conformational stability of globular proteins. Lipids can form complexes with amylose and proteins, decrease the solubility and co‐ solubility of biopolymers, and provoke phase separation of biopolymer mixtures (Tolstoguzov 2003). 7.2.2  Gluten Replacement in Empanadas: A Complex Task to Cover a Larger Population Empanadas are extensively consumed in Latin America, but those prepared with wheat flour that contains gluten are unsuitable for people suffering from celiac disease. Celiac disease is an autoimmune enteropathy triggered by the ingestion of gluten‐ containing grains in susceptible individuals. The gliadin fraction of wheat gluten and similar alcohol‐soluble proteins in other grains (mainly barley, rye, and oats) are the environmental factors responsible for the development of the intestinal damage (Rubio‐ Tapia and Murray 2010). Finger‐like protrusions called villi, through which nutrients from the food are absorbed into the bloodstream, are irreversibly damaged. Without villi, a person becomes ill and is malnourished, regardless of the quantity of food eaten (Arendt et al. 2002; Wieser et al. 2014). The pathological changes and symptoms generally resolve with withdrawal of gluten from the diet and a strict adherence to a gluten‐ free (GF) diet throughout the patient’s lifetime.

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7  Textural Characteristics and Viscoelastic Behavior of Traditional Argentinian Foods

GF starches are used to formulate doughs; however, they fail to form a continuous phase and thus lack the necessary structure for the production of good‐quality dough. Therefore, GF bakery products require polymeric substances that mimic the viscoelastic properties of gluten in dough. Low quality of the GF products on the market has led to efforts to improve their poor structure, mouthfeel, and flavor (Arendt et al. 2002; Gallagher 2009; Lazaridou et al. 2007). The search is for key components needed to produce dough with good elasticity, resistance to puncture, and stretching. Development of GF bakery products involves the use of hydrocolloids to replace the gluten matrix network to produce a high‐quality GF food. The key issues in GF empanadas or pie crusts production are related to the lack of gluten in the matrix to provide elasticity, resistance to puncture, and stretching of the dough. Hydrocolloids have been found to be great improvers of textural aspects of the dough in several works (Capriles et al. 2016; Larrosa et al. 2016; Rosell and Matos 2015); and are practically indispensable for the formulation of any kind of GF dough. Xanthan gum and guar gum are some of the hydrocolloids that may be added to GF doughs. Interactions between xanthan gum and guar gum have synergistic effects (BeMiller and Whistler 1996), such as enhanced viscosity that can improve dough handling. Another possibility is to incorporate egg or dairy proteins, which are considered as functional and versatile ingredients adequate for many food products. Elastic properties, resistance to puncture during baking, and a dough matrix easy to laminate during production without breaking are the most important mechanical attributes of this type of dough. Rheological and textural characterization of doughs provides important information, allowing ingredient selection strategies to design, improve, and optimize the final product. It must be taken into account that the replacement of gluten by starch, proteins, lipids, and hydrocolloids results in a major challenge to the food technologist, mainly from the structural and rheological point of view. A comprehensive rheological and textural characterization of GF empanadas (nonfermented dough), was reported in previous works by Lorenzo et al. (2009), Lorenzo et al. (2008). In this case study, a wide screening of dough compositions was performed studying the effect of dough moisture, content of protein (egg and whey concentrate), and content of hydrocolloids (xanthan: guar mixtures, 2 : 1 ratio) on the mechanical properties of a dough prepared with corn and cassava starches in a 2 : 1 ratio. A first step in the analysis involved an optimization process of the composition based on textural and rheological attributes. Maximum breaking force (FP) determined from puncture tests performed on disk dough (40 mm diameter and 2 mm thick) showed that less force was needed to puncture the dough when more water was added to the formulation, while lower dry egg content increased the maximum puncture force for samples with 3% gum (Figure 7.2a and b). Probably when egg protein content decreased, more water was available to form the xanthan/guar network, thus resulting in a harder dough. On the other hand, at high water and low gums contents, the maximum force at puncture was smaller at low egg content, because there were less polysaccharide molecules to form strong entanglements and the contribution of the egg proteins to structure was noticeable. At low water (W) and high gum (G) content, the decrease of whey protein concentrate (WPC) weakened the dough, while the opposite effect was found for the other formulations.

(a)

(b) 140 120

120 100

80

FP (mN)

FP (mN)

100

140

water 51% water 53% water 55%

60 40 20 0

dry egg 3.5% dry egg 5.0% dry egg 6.5%

80 60 40 20

1.5%

2.25% gum level

(c)

3.0%

0

1.5%

2.25% gum level

3.0%

450 400

Puncture force (mN)

350 300 250 200 150 100 50 0

0

2

4 6 Distance (mm)

8

10

(d) 400 High solid content Margarine: 20% Sunflower oil: 20% 30%

350

30%

Elongation force (mN)

300 250 200 150 100 50 0 0

5

10 15 extensibility (mm)

20

Figure 7.2  Gluten‐free (GF) empanada dough. Effect of gum (xanthan/guar) content at different levels of water (a), and dry egg (b) on puncture force (FP). (c) Effect of gum type on puncture force: ● xanthan/ hydroxypropyl‐methylcellulose (HPMC); ▲ xanthan/guar; ■ HPMC. (d) Effect of lipid phase on dough elongation tests for doughs containing xanthan/guar. Cross‐sectional area: 2 mm thick × 10 mm width.

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7  Textural Characteristics and Viscoelastic Behavior of Traditional Argentinian Foods

Frequency dependence of the storage (G′) and loss (G″) moduli within the linear viscoelastic range for a formulation containing xanthan: guar mixture, 2 : 1 ratio is shown in Figure  7.1c. G′ was always greater than G″ in the frequency range assayed and the increase of G′ and G″ with frequency was small being the curves almost parallel. This result could be explained in terms of the synergistic interaction between xanthan gum and galactomannans (previously mentioned). The inspection of the frequency sweep curves also showed that elastic characteristics increased (higher storage moduli) when gum content was raised or water diminished; in this case a more rigid dough structure and a more elastic polymer network, related to stronger entanglements among hydrocolloids molecules was observed, confirming the results obtained by the texture experiments. The analysis included an optimization of the formulation of the GF empanada disks. The optimal formulation with high content of hydrocolloids and whey protein concentrate created a dough that is easy to handle because they resisted better the tearing that might occur during dough industrial preparation (higher puncture force). Since they also presented high elongation forces and extensibility, they would resist without tearing the stretching of the dough that would occur at the initial stage of cooking due to air and vapor dilatation. Type of hydrocolloids is another aspect to be considered in GF doughs to replace the gluten functionality. Several hydrocolloids have been used in a range of GF bread formulas because they change dough properties and improve product structure, texture, acceptability, and shelf life (Mir et al. 2016). Among the various hydrocolloids, hydroxypropyl‐methylcellulose (HPMC) and xanthan gum are the most commonly used due to their promising effects on the quality of the final product (Anton and Artfield 2008). When HPMC and mixtures of HPMC/xanthan gum were evaluated in GF empanada doughs, interesting results were found on their textural attributes (Lorenzo et al. 2009). Figure 7.2c shows how the type of hydrocolloid affects the characteristics of empanada GF dough. It can be observed that those formulations containing xanthan gum exhibited the same average values for FP regardless of the other hydrocolloids present in the dough. When the hydrocolloid matrix was only formed by HPMC, the samples presented extremely low values for FP, elongation force (FE) and extensibility (D). This fragile behavior turns the formulation into unsuitable dough for industrial handling since it would not resist the large stretching forces leading to cracks and tears in the dough disks. Moreover, this lack of resistance in the structure would cause spills during baking, producing an important quality loss in the final product. Lipids are an important ingredient used in empanada dough manufacture. They are the third‐largest components after flours/starches and water. Traditionally, animal fat like tallow, lard, and butter has been used (to a lesser extent, also margarine and shortening). Fat performs a textural function in dough. During the mixing process, there is competition for the flour surface between the aqueous phase and the fat. When fat coats the flour, this network is interrupted and the eating properties after baking are less hard, shorter, and more inclined to melt in the mouth. If the fat level is high, the lubricating function in the dough is so pronounced that little or no water is required to achieve a desired consistency. During the last decade, there has been a growing interest in developing products with a healthier lipid profile; recommendations about lipid consumption (WHO 2003) encourage diminishing the intake of saturated fat and increasing the unsaturated lipids. However, the industrial production of empanadas dough with wheat flour still employs margarine in its formulation.

7.2 Empanadas

Sunflower oil, margarine with high solid fat content (for industrial uses), and retail margarine (with low solid fat content) were analyzed in GF dough preparation at different proportions, and changes in mechanical attributes were reported (Lorenzo et  al. 2009). When margarine was used, the increase in fat content produced doughs with higher resistance to puncture, while the opposite effect was found using sunflower oil. Both factors, type and lipid content, also affected significantly elongation force and dough extensibility. Margarine provided ductility to the dough; more markedly so in the case of industrial margarine, which contained a higher proportion of solid fat than the retail (all‐purpose) one. The formulation with high sunflower oil content showed the lowest values of FP, FE, and D, making it the least suitable for industrial handling (Figure 7.2d). The effect of lipids on the viscoelastic characteristics of the dough was also analyzed, and a marked increment of G′ with the solid fat content of the lipid phase was observed. Textural properties of the baked dough and sensorial perception of the consumers are crucial aspects to be considered to assess the quality of the final product. Therefore, not only are handling properties important to evaluate but so is the consumers’ acceptance of the product. A group of 40 panelists evaluated ground beef– filled empanadas prepared with two GF dough, one of the formulations previously described in this chapter with xanthan gum/HPMC mixture and sunflower oil 20%, and a GF dough purchased from a local market (Lorenzo et al. 2009). The panelists did not find differences in flavor, texture, and overall acceptability between both formulations (P  d > c > b > a with incasing oil contents, but the cohesiveness of gomatofu increased in order of c > d > e > b > a; the sample c control gomatofu showed the highest value on the first stor‑ age day. The adhesiveness increased in order of a > b > e > d > c; the sample c was con‑ versely the lowest for cohesiveness. With increase in the number of storage days, Table 8.1  Average value of texture parameter of gomatofu with various oil contents on the first storage day (Sato et al. 2005). Sample (oil contents)

Hardness (× 102N/m2) Adhesiveness (× 102N/m2) Cohesiveness (× 10−1)

a. Defatted

(0%)

1.40 ± 0.09

2.01 ± 0.12

2.17 ± 0.12

b. Defatted

(0.42%)

1.49 ± 0.10

1.73 ± 0.10

2.25 ± 0.15

c. Control

( G″) over most of the accessible frequency ranges (0.1–100 Hz). There was a slight increase of G′ when the coconut milk amount was reduced to 25%, and the gel‐like characters became more pronounced with less variation over frequency range. Pudding formed with 45% coconut milk showed a strong dependency of frequency, e.g. at the frequency of 50 Hz, the G″ took over the G′. This result indicated that addition of more coconut milk resulted in a weaker pudding,

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which is possibly due to the presence of more fat in the formulation. Traditionally, more coconut milk is preferred because it creates a softer and creamier texture. 10.3.2.3  Production of Pudding Rumput Laut

Conventional pudding preparation by the local generally involves cleaning, washing, and soaking of dried cottonii seaweeds in water for approximately 12 hours, and boiling the soaked seaweeds with a mixture palm sugar and coconut milk. Boiling can take up more than one hour depending on the amount of seaweeds and the cooking temperature used. The hot mixture of seaweed is sieved to pass a waiving bamboo basket, then set to form a relatively firm gel having a characteristic of smooth and brittle texture with brownish color resembling palm sugar. Traditionally, the texture of pudding can be modified by varying the concentration of coconut milk. Coconut milk (santan kelapa) is one of the most common cooking ingredients in Indonesia. It is a milky white oil‐in‐water emulsion obtained from the extraction of coconut flesh. Fat and water are the major components in coconut milk where carbohydrate, protein, and minerals are present in the small percentages (Tansakul and Chaisawang 2006). Local people prefer to use a fresh coconut milk obtained from grated coconut flesh due to the fresh flavor it confers; however, canned or powdered coconut milks are acceptable substitutes. 10.3.3  Soy‐Based Foods – Tempeh (Fermented Soybeans) The consumption of protein‐rich foods of plant origin in Indonesia is increasing in popularity compared to animal‐based foods due to the latter being associated with ­lifestyle‐related diseases such as heart disease, diabetes, and other chronic diseases. Soybeans are one of the major food ingredients in the Indonesian diet and are an ­economical source of protein. The protein in soybean is an excellent source of amino acids, in which the quality is comparable to that of animal protein sources such as milk and meat. Hence, soybean protein is often used to replace animal proteins in an individual’s diet. The soybeans are cholesterol‐free and are low in saturated fat and calories. Tempeh, tahu (tofu), and kecap (soy sauce) are the most common soy‐based protein sources consumed, and they play significant roles in Indonesian diets. Besides those three, soy milks, oncom (fermented of byproducts of tofu), and tauco (salted, fermented soybean) are also soybean‐based traditional Indonesian foods. Tempeh (Figure 10.4a) is traditional fermented soybeans originating from Jawa. Similar to tofu, tempeh must be further processed before its consumption (i.e. deep fried, grilled, boiled, or steamed). Keripik tempeh (tempeh crackers), tempeh goreng (deep‐fried tempeh), sambal goreng tempeh (stir‐fried tempeh), and tempeh bacem (cooked tempeh with spices) are some examples of Indonesian traditional dishes prepared from tempeh. Nowadays, tempeh has been gaining in popularity and it has been incorporated extensively as a plant‐based protein for vegan and many other type of modern dishes. In Indonesia, tempeh is made by fermentation of soybeans; however, other substrates can substitute the soybeans, such as peanuts, coconuts, winged beans, chickpeas, navy beans, fava beans, cowpeas, broad beans, lupin, and bakla (Lund 1988). The common microflora used in tempeh fermentation are Rhizopus species, such as Rhizopus microspores, Rhizopus oligosporus, and Rhizopus oryzae (Nout and Kiers 2005); however, R. oligosporus is generally used as a starter culture by many local home industries.

10.3  Textural Properties of Indonesian Foods

(a)

Teak wood leaves

(b)

(c) 8000

0.6 0.5

6000

Cohesiveness

Hardness (gram-force)

Plastic

Banana leaves

4000 2000 0

0.4 0.3 0.2 0.1

Plastic

Teak wood leaves Packaging type

Banana leaves

0

Plastic

Teak wood leaves

Banana leaves

Packaging type

Figure 10.4  (a) Tempeh available in the market with different type of packaging; (b) the hardness; and (c) the cohesiveness of the tempeh (1.5 × 1.5 × 1.5 cm, L × W × H) by texture analyzer. Compression speed, 0.3 mm/s; the trigger force, 0.05 N; 25 °C.

The fermentation process of soybeans by Rhizopus species formed a compact, cake‐ like product, bound together by thick white mycelia that gives a dense texture. During fermentation, the formation of total free amino acids of soybean increased proportionally to 3–10‐fold the fermentation time. This is due to the hydrolysis of the protein into amino acids and small peptides by R. oligosporus (Handoyo and Morita 2006). Futhermore, according to these authors, the matured tempeh after 72 hours of fermentation contains some major essential amino acids such as lysine, leucine, phenylalanine, and isoleucine, together with semi‐essential amino acids and nonessential amino acids, which account for a total of 1204 mg/100 g soybean. Beside the proteins, tempeh also contains glycosidised isoflavones and vitamins (Karyadi and Lukito 1996). Tempeh has a unique flavor that is often described as a mushroom‐like nutty flavor (Jeleń et al. 2013). This flavor is probably produced by biotransformation of soy components during fermentation process. According to these authors, the microorganisms acting in the tempeh fermentation are responsible for the unique flavor properties.

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10  Textural Characteristics of Indonesian Foods

These authors have identified about 19 key fundamental odorants of tempeh using gas chromatography–mass spectrometry and found out that the frying process of tempeh could increase the key odorants in tempeh. Traditionally, the production of tempeh involves the main process of soaking the ­soybeans, followed by boiling the soaked beans. The extent of soaking and cooking may vary according to the producers. The soaking process can also be completed overnight in order to shorten the cooking process. According to Nout and Kiers (2005), soaking of soybeans can increase the moisture content of the beans, hence rendering the beans palatability, enable microbial activity during the fermentation, and extract naturally occurring antimicrobial substances (saponins) and bitter principles. The cooked soybeans are then de‐hulled by treading on them in a bamboo basket. In many small‐scale tempeh industries in Indonesia, the de‐hulling process after cooking can be excluded if de‐hulled soybeans are used. The de‐hulled bean is available in the market. The inoculation by the culture of R. oligosporus or any Rhizopus species is carried out at room temperature up to approximately 30–48 hours by adding ~104 colony‐forming units g−1 (CFU g−1 prepared substrate) of the culture (Nout and Kiers 2005). The inoculated soybeans can be packed in perforated plastic bags, banana leaves or teak wood leaves and allowed to ferment at a room temperature (c. 25 °C). Perforation is crucial in tempeh making as the fermentation is aerobic. Tempeh fermented for more than 48 hours is considered as an over fermented tempeh where the texture is deteriorated (Handoyo and Morita 2006). It is usually characterized by softer texture with darker color and fairly strong flavors. The dark color of overfermented tempeh is due to the dark mycelium or sporulation, which is undesirable to the consumer (Lund 1988). 10.3.3.1  Texture Properties of Tempeh

The texture and the rheological properties of tempeh are very important characteristics because these properties determine the product preference and competitiveness in the market (Handoyo and Morita 2006). However, to date very little study has been reported on the textural properties of tempeh. The texture of tempeh can be influenced by many factors such as fermentation time and temperature, the amount and type of culture incorporated, the preparation of soybean before inoculation, and the type of packaging materials. Traditionally, Indonesian tempeh is packed, incubated, and sold in daun pisang (banana leaves), daun waru (hibiscus leaves), or daun jati (teakwood leaves) before plastic is introduced as a material of packaging. There is no specific standard process on tempeh manufacturing in Indonesia. Furthermore, with a large number of small‐scale tempeh industries, many variations can results in tempeh flavor or textural properties among different region or producers (Astuti et al. 2000). Handoyo and Morita (2006) studied the effect of fermentation time on textural properties of tempeh. These authors found that the fermentation time of 48 hours resulted in the firmest tempeh texture, suggesting the optimum growth of fungal has been achieved. Further prolongation of the fermentation period had led to a significant reduction in the hardness of tempeh. This was due to the developed mycelium network that was weaker and to a reduction in regeneration of new mycelia. Figure  10.4b shows the hardness of three type of tempeh available in the market ­prepared with different type of packaging materials such as plastic, teakwood, and banana leaves. The hardness of tempeh was obtained by compression tests performed using a Stable Micro System TA‐XT2 Texture Analyzer (Stable Micro Systems, Surrey, England). The tempeh samples from different type of packaging were cut into cubes

­  References

(1.5 × 1.5 × 1.5 cm, L × W × H). As shown in Figure 10.4b, there was no obvious d ­ ifference in hardness of tempeh sold in the market when packed by plastic, teakwood, and banana leaves. Possibly this is the tempeh texture that consumers preferred and maintained by industries. It is important to note that tempehs wrapped in banana and ­teakwood leaves represent the most desired texture and flavor. Interestingly although there was no difference in firmness, the tempeh cohesiveness (Figure  10.4c) indicated significant difference. Tempeh wrapped by teakwood leaves showed the most cohesive texture compared to those that were wrapped by plastic and banana leaves. Cohesiveness is defined as the strength of internal bonds making up the body of the product (Szczesniak 1963). The cohesiveness of tempeh could be governed by distribution of mycelium that connects the soybean cotyledons, and the thickness of the mycelium, as well as the amount of mycelium. The fermentation of tempeh is aerobic, so the correct amount of oxygen is essential for the growth of Rhizopus. That is, too little oxygen may lead to insufficient growth of mycelium and, by contrast, an excess of oxygen will cause the mycelia to sporulate, which results in an undesirable color and texture (Lund 1988). Perhaps, the fermentation occurring in the teakwood leaves favors the optimum growth of mycelium, which confers the cohesiveness.

­References Ahmad, F.B., Williams, P.A., Doublier, J.‐L. et al. (1999). Physico‐chemical characterisation of sago starch. Carbohydrate Polymers 38 (4): 361–370. Aslan, L.O.M., Iba, W., Bolu, L.O.R. et al. (2015). Mariculture in SE Sulawesi, Indonesia: culture practices and the socio economic aspects of the major commodities. Ocean & Coastal Management 116: 44–57. Astuti, M., Meliala, A., Dalais, F.S. et al. (2000). Tempe, a nutritious and healthy food from Indonesia. Asia Pacific Journal of Clinical Nutrition 9 (4): 322–325. Campo, V.L., Kawano, D.F., Silva, D.B.d. et al. (2009). Carrageenans: biological properties, chemical modifications and structural analysis – a review. Carbohydrate Polymers 77 (2): 167–180. Elfahmi, Woerdenbag, H.J., and Kayser, O. (2014). Jamu: Indonesian traditional herbal medicine towards rational phytopharmacological use. Journal of Herbal Medicine 4 (2): 51–73. FAO (Food and Agricultural Organization) (2012). Food Outlook. http://www.fao.org/ docrep/016/al993e/al993e00.pdf (accessed 2 April 2015). Hall, R. (2009). Indonesia, geology. In: Encyclopedia of Islands, 454–460. Berkeley, California: University of California Press. Handoyo, T. and Morita, N. (2006). Structural and functional properties of fermented soybean (tempeh) by using Rhizopus oligosporus. International Journal of Food Properties 9 (2): 347–355. https://doi.org/10.1080/10942910500224746. Jeleń, H., Majcher, M., Ginja, A. et al. (2013). Determination of compounds responsible for tempeh aroma. Food Chemistry 141 (1): 459–465. Karyadi, D. and Lukito, W. (1996). Beneficial effects of tempeh in disease prevention and treatment. Nutrition Reviews 54 (11): S94. Lucey, J.A., Tamehana, M., Singh, H. et al. (1998). A comparison of the formation, rheological properties and microstructure of acid skim milk gels made with a bacterial culture or glucono‐delta‐lactone. Food Research International 31 (2): 147–155.

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Lund, C.M. (1988). Effects of inocula and incubation times on selected sensory and physical characteristics of tempeh. Kansas State of University, Kansas. Manilal, K. and Sabu, T. (1985). Cyclea barbata miers (menispermaceae): a new record of a medicinal plant from South India. Ancient science of life 4 (4): 229. Minh Duc, N., Elfahmi, Ruslan Wirasutisna, K. et al. (2014). International Seminar on Natural Product Medicines, ISNPM 2012 Effect a Glycosidic Flavonol isolated from green grass jelly (Cyclea barbata Miers) leaves. Procedia Chemistry 13: 194–197. Mohamed, S., Hashim, S.N., and Rahman, H.A. (2012). Seaweeds: a sustainable functional food for complementary and alternative therapy. Trends in Food Science & Technology 23 (2): 83–96. Neish, I.C. (2013). Social and economic dimensions of carrageenan seaweed farming in Indonesia. Social and economic dimensions of carrageenan seaweed farming, Fisheries and Aquaculture Technical Paper (580), 61–89. Nout, M. and Kiers, J. (2005). Tempe fermentation, innovation and functionality: update into the third millenium. Journal of Applied Microbiology 98 (4): 789–805. Opoku, G., Qiu, X., and Doctor, V. (2006). Effect of oversulfation on the chemical and biological properties of kappa carrageenan. Carbohydrate Polymers 65 (2): 134–138. Setiardja, A.G. (1993). Hak‐hak Asasi Manusia Berdasarkan Ideologi Pancasila. Penerbit Kanisius. Steenbergen, D.J., Marlessy, C., and Holle, E. (2017). Effects of rapid livelihood transitions: examining local co‐developed change following a seaweed farming boom. Marine Policy 82: 216–223. Szczesniak, A.S. (1963). Classification of textural characteristics. Journal of Food Science 28 (4): 385–389. Tansakul, A. and Chaisawang, P. (2006). Thermophysical properties of coconut milk. Journal of Food Engineering 73 (3): 276–280. Tsoga, A., Richardson, R.K., and Morris, E.R. (2004). Role of cosolutes in gelation of high‐methoxy pectin. Part 1. Comparison of sugars and polyols. Food Hydrocolloids 18 (6): 907–919. Wahyudi, B.A., Octavia, F.A., Hadipraja, M. et al. (2017). Lemang (Rice bamboo) as a representative of typical Malay food in Indonesia. Journal of Ethnic Foods 4 (1): 3–7. Wouthuyzen, S., Herandarudewi, S.M.C., and Komatsu, T. (2016). Stock assessment of Brown seaweeds (Phaeophyceae) along the Bitung‐Bentena coast, North Sulawesi Province, Indonesia for alginate product using satellite remote sensing. Procedia Environmental Sciences 33: 553–561. Wright, T. and Sugiarti, M. (2015). Indonesia Grain and Feed Update October 2015: El Nino. Global Agricultural Information Network, USDA Foreign Agricultural Service. Yuliarti, O., Chong, S.Y., and Goh, K.K.T. (2017a). Physicochemical properties of pectin from green jelly leaf (Cyclea barbata Miers). International Journal of Biological Macromolecules 103 (Supplement C): 1146–1154. Yuliarti, O., Hoon, A.L.S., and Chong, S.Y. (2017b). Influence of pH, pectin and Ca concentration on gelation properties of low‐methoxyl pectin extracted from Cyclea barbata Miers. Food Structure 11: 16–23. Yumarma, A. (1996). Unity in Diversity: A Philosophical and Ethical Study of the Javanese Concept of ‘keselarasan’, vol. 19. Gregorian Biblical BookShop.

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11 Textural Characteristics of Thai Foods Rungnaphar Pongsawatmanit Kasetsart University, Bangkok, Thailand

11.1 ­Introduction Consumers consider the food quality in terms of appearance, flavor, texture, and stability. Food texture is an index of quality and refers to those qualities of a food that can be felt with the fingers, tongue, teeth, or palate. Texture is related to the perception of food with different structure formation within the product and how the product behaves when handled and eaten (Rosenthal 1999). Another definition is “texture is a sensory property, and can be detected only by humans” (Szczesniak 2002). The food texture is the most essential factor affecting the palatability of foods (Nishinari 2009). Each type of foods has its own characteristics because of the difference in chemical compositions, processing, and structure. Therefore, the texture of a food depends on the type of food, ingredient formulation, or processing (e.g. crisp fried rice crackers or potato chips, hard candy, tender sponge cake or creamy ice cream). Food texture is one of the qualities that can be changed as it moves through the food chain after production. The storage stability in terms of texture depends on food types or ingredients used in the formulation, processing, and packaging. Thai foods could be grouped into 20 groups (Table  11.1) according to the report of National Bureau of Agricultural Commodity and Food Standards (ACFS) (2016) for the national food consumption of Thai people surveyed in 2013–2015 for the age group ≥3 years. The survey of consumption was carried out for 509 food items. Currently, Thai foods have become more popular worldwide because of their delicious use of herbs and spices. In addition, higher quality and safety of food products have been produced under the GMP (Good Manufacturing Practice) and HACCP (Hazard Analysis and Critical Control Point) systems, especially for exported foods. The spices and herbs have been added into the formulation, leading to higher health benefit. Globalization has taken Thai food into urban areas across the world. With the driving force of the appeal of modern lifestyles, marketing, convenience, and speed of food product distribution, more and more persons consume fast‐food regularly (Seubsman et al. 2009). Thai food lends itself well to the fast‐food market.

Textural Characteristics of World Foods, First Edition. Edited by Katsuyoshi Nishinari. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

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Table 11.1  Food groups divided for the national food consumption of Thai people surveyed in 2013–2015. Food group

Group name

1

Cereal grains and their products

2

Tubers and their products

3

Beans, seeds, and their products

4

Vegetables and their products

5

Fruits and their products

6

Eggs and their products

7

Meat, aquatic animals, and their products

8

Milk and their products

9

Ice cream

10

Alcoholic beverages

11

Soft drinks/non-alcoholic beverages

12

Snacks

13

Thai desserts

14

Sugars and their products

15

Artificial sweeteners

16

Lipid (fat and oil) and their products

17

Seasonings

18

Chili pastes

19

Food supplement products

20

Water

Source: National Bureau of Agricultural Commodity and Food Standards (2016).

Thai food varies, depending on the geographical regions. However, the desired t­extural quality of food product is moving forward to satisfy the consumers’ needs. Along with the consumption of modern food and local food in Thailand, historical and geographical background, selected food samples with sensory evaluation and instrumental measurement, and the health benefit of Thai food in terms of antioxidant will be discussed.

11.2 ­Historical and Geographical Background of Thai Food Thailand is a Southeast Asian country and has a tropical climate. According to geographical studies, Thailand could be divided into six regions (the Northern Thailand, the Northeastern Thailand, the Central Thailand, the Eastern Thailand, the Western Thailand, and Southern Thailand). However, Thai cuisine may be described as four regional cuisines corresponding to four main regions of the country: Northern, Northeastern (called Isan), Central, and Southern. Thai food had been influenced by

11.2  Historical and Geographical Background of Thai Food

the neighboring countries and regions leading to transnational interaction for ­centuries. Chinese influences on Thai cooking include the use of noodles, soy sauce, and other soy products. Fish sauce, which is used in almost every dish nationwide, came from China. India shared not only the Buddhist religion but also spicy seasonings such as cumin, cardamom, and coriander, as well as curry dishes. To the southern area, Malaysia also shared some seasonings, as well as coconuts (including coconut milk shown in Figure  11.1a) and the satay. A Thai sweet desserts called Thong Yip, pinched gold egg yolks, and Thong Yod, gold egg‐yolk drops (Figure 11.1b), like many other egg‐based sweets, are modified from Portuguese dishes due to an earlier contact with Western cultures in the seventeenth century that left a culinary legacy. The Thai (a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

Figure 11.1  Typical Thai food, desserts and fruit. (a) Coconut milk, (b) Thong Yip and Thong Yod, (c) grilled chicken, (d) sweet chili sauce, (e) durian fruit, (f) tom yum kung, (g) nham (Thai‐style fermented pork sausage), (h) look choup (fruit‐shaped mung bean paste coating with agar), (i) khanom tan (toddy palm cake prepared by steaming).

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Royal Cuisine using special cooking method and ingredients from the Ayutthaya kingdom (1351–1767 ce) (Wikipedia 2017) are another great influence to the cuisine of the Central region. Like the basic tastes in Japan, the Thais based their recipes on blending five basic tastes: sour, sweet, salty, bitter, and umami. The cooking of Thai foods is balanced to draw out different flavors in a dish. Curries (prepared by using chili paste with and without coconut milk called curry) can be found in all regions of Thailand. Hot chilies appear in many main dishes. Other common ­flavorings are fish sauce, dried shrimp paste, lemon grass, and spices such as garlic, basil, ginger, coriander, cumin, cardamom, chili powder, and cinnamon. Many dishes are served with condiments, such as fish sauce mixed with fresh chili or chili powder. Soup is served to balance the hot flavors in many Thai dishes. In the modern world, urbanization, industrialization, and technological changes have transformed food systems, affecting food production, processing, distribution, and retailing. Thailand is a country with a strong food culture that is connected to local agriculture and retail market or wet market (or called fresh market), which provides the sources of healthy, fresh foods (Kelly et al. 2013). Approximately 40% of the Thai population works in the agricultural sector compared with 80% workforce in 1960 (Kelly et al. 2010). The number of workers in the agricultural sector has fallen as Thais have moved to urban areas (Webster 2005). The workforce changes and moves toward more modern urban lifestyles have also changed dietary and nutrition preferences. Therefore, the food industry distributes a wide range of products for supermarket shelves. An important factor in health profile is the rapid change in the diet of the Thai population. Traditional Thai diets help prevent chronic diseases. However, the traditional diets, particularly in urban areas, are being replaced by the food containing higher fats, salts, sugars, and animal products and lower intakes of fresh fruits and vegetables (Kelly et  al. 2013). This creates the health outcomes for Thai people in a situation of rapid increase in obesity and diet‐related diseases (noncommunicable diseases: NCDs) (Chopra 2003). To satisfy consumers’ needs for health, cross‐cultural, and convenience food, the healthy product development of Thai dishes are produced. Convenience food is defined according to the Cambridge dictionary as “food that is almost ready to eat when it is bought and can be prepared quickly and easily.” Rice is a dietary staple in Thailand, including glutinous and nonglutinous rice. Glutinous rice is widely eaten but more popular in Northern and Northern‐East regions of Thailand. According to the national food consumption of Thai people surveyed in 2013–2015, the mean consumption values as cooked form of nonglutinous and glutinous rice were about 232 and 78 g/person/day), respectively (National Bureau of Agricultural Commodity and Food Standards 2016). The rice (both in the raw or cooked forms) and rice flour is also used as an ingredient of some dishes and dessert preparation. Many studies report the texture of cooked rice and rice starch‐based products (Li and Gilbert 2018; Li et al. 2016); Most main dishes use beef, chicken, pork, seafood, or eggs. Fried, baked or grilled chicken (Figure 11.1c) is popular throughout the country. The sweet chili sauce (Figure 11.1d) is always served with grilled or fried chicken. Thailand has some specific vegetables and fruits from local areas, such as durian (Figure  11.1e) and mango‐steen, mostly found in the Eastern and Southern regions where the texture will change from hard to soft when ripening due to the climacteric characters. Ripening is the process associated with the changes in the composition (i.e.

11.2  Historical and Geographical Background of Thai Food

conversion of starch to sugar) that fruits attain their desirable quality in terms of flavor, color, palatable nature, and other textural properties. Thai people eat a variety of ­tropical fruits for dessert, including mangoes, papayas, and jackfruit. Usually, Thai food differs somewhat from one region to another. However, because the food distribution system in Thailand is so well developed, all food types could be found throughout the country. For the group of tubers and their products, tapioca starch is a product used widely in many processed foods. Tapioca starch produced from cassava roots is a favorable thickener used in Thailand due to its high viscosity, clear appearance, and low cost compared to other starches (Pongsawatmanit et al. 2013). The starch in low concentrations is used for preparing pudding, pastries, and soup (Moore et al. 1984), including low‐fat frozen dessert by creating a smooth, creamy mouthfeel (Whelan et al. 2000). In contrast, a high concentration of tapioca starch could be used as a major ingredient to form a gel such as tapioca pearl and various types of desserts. However, the quality of tapioca starch pastes and gels may face the problems of low stability against shear or other mechanical stimuli and the gels are subjected to the deterioration induced or caused by retrogradation (Pongsawatmanit et  al. 2007). The retrogradation in the products, especially stored products, can change qualities. In Thailand, modified starch or hydrocolloids are added to the formulation of food to improve or to maintain the overall quality during distribution and storage by modifying the rheological and textural properties of foods. Many studies have reported the effect of hydrocolloids on starch paste and/or gel properties. Coconuts play an important role in the Thai diet. Coconut milk (Figure 11.1a) and shredded coconut are used in many dishes, especially curry or desserts. Many Thai desserts can be easily found. In general, the meals end with serving fruit and sweet ­desserts (cake called Khanom in Thai and liquid desserts, such as cooked bananas in coconut milk). Coconut milk usually contains about 15–18% fat (wet basis) (Judprasong et  al. 2016), which determines the viscosity. The viscosity of coconut milk plays an important role in both taste and stability of the emulsion (Chonweerawong et al. 2004). Typical Thai food, desserts, and fruit are shown in Figure 11.1. Thai curry, for example, has its own characteristics with different in both taste and viscosity due to the different ingredients and concentrations used in the formulation: spicy seasonings such as cumin, cardamom, and coriander. For example, tom yum kung is a popular hot and sour soup containing prawn (Figure 11.1f ). Thai food has been a product of transnational interactions for centuries and is a combination of indigenous foods and the influences of culinary traditions from Indian, Chinese, or other countries. The Thais based their recipes on blending some tastes: sour, sweet, oily, and salty. Adding the ingredients (acid, sugar, lipid, and salt) to create such taste and flavor affect the texture and structure of the food. Fish sauce is a condiment and important food ingredient used in most Thai dish and creates specific flavor in the finished food product. Fried chicken for both with or without batter is another popular food. Traditional fermented meat products (such as nham [Thai fermented pork sausage] shown in Figure 11.1g) and fishery products are widely eaten with some vegetables. Lactic acid bacteria is used to produce these fermented products. The meals end with serving fruit and sweet desserts divided into two categories: cakes called khanom and liquid desserts (bananas or taro or sweet potato boiled in coconut milk). In fact, Thai people take three meals daily and moreover frequently snacks. Therefore, many food shops are found in every public place because of the habit of preferring the snack all day. There are many

155

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11  Textural Characteristics of Thai Foods

Thai desserts such as look choup prepared from fruit‐shaped mung bean paste coating with agar (Figure 11.1h) and khanom tan (Figure 11.1i) prepared from toddy palm by steaming. The textures of these products are different depending on the ingredients and process (baking, steaming, or frying) used for production. Supermarket revolution recently has replaced the “traditional” retail sectors consisting of wet markets, and small, family‐run shops (Reardon et al. 2005). These changes have been driven by both sides of demand and supply. Urbanization, rising incomes, and globally connected lifestyles increase the demand for novel foods supplied by modern food retail with more convenient and higher quality from consumer sides and more shelf life required from the retails.

11.3 ­Selected Food Samples with Sensory Evaluation and Instrumental Measurement Food quality is evaluated in terms of appearance, flavor, texture, and stability. The ­texture as an index of quality is defined as “all the mechanical, geometrical, and surface attributes of a product perceptible by means of mechanical, tactile and, where appropriate, visual and auditory receptors” (Rosenthal 1999). Food texture is perceived as food is manipulated and eaten, and thus the structure of the product changes. The mechanical properties of food texture, such as hardness, cohesiveness, crispness, crunchiness, and denseness, could be the indicators of freshness and wholesomeness of the products. Food texture provides a sensory indicator to consumers by stimulating the responses from consumers (Civille 2011). The texture of foods may be different, depending on food products (e.g. hard candy, tender cake, crisp rice cracker, or sticky toffee), and plays an important role in the success of product development. During research and development, when the new or alternative ingredients are used, texture measurement can be performed to compare with existing ingredients. In production, food texture analysis is applied to the measurement and control of process variations such as temperature, humidity, or cooking time. It is also used to indicate the freshness and stability of the food product. The texture of a food can change during storage. Fruits and vegetables lose water, leading to wilt or loss of turgor pressure. Bread becomes hard and stale. Ice cream becomes gritty due to the precipitation of lactose and ice crystal growth in the freezer with temperature fluctuation leading to thawing and refreezing. The measurements of texture and sensory evaluation depend on the types of food. Evaluation of the texture consists of measuring the response of a food when it is subjected to forces such as shearing, cutting, chewing, stretching, or compressing. Food texture depends on the rheological properties of the food (Nishinari 2009). Rheology is defined as the science of deformation and flow of materials, or reaction of a food (flow, bend, stretch, or break) when a force is applied to it. From a sensory perspective, the texture of a food is evaluated when it is chewed. The teeth and tongue exert a force on the food, and how easily it breaks or flows in the mouth determines whether it is perceived as hard, brittle, thick, runny, and so on. The term mouthfeel is a general term used to describe the textural properties of a food as perceived in the mouth. Thai foods could be in the form of solid food, semi‐solid, liquid foods, or mixtures of solid and liquids. Table 11.2 shows the measurement of texture and sensory evaluation in some

11.3  Selected Food Samples with Sensory Evaluation and Instrumental Measurement

Table 11.2  Measurement of texture and sensory evaluation in selected Thai foods. Product

Texture analysis

Sensory

References

Texture profile analysis (TPA) ●● hardness ●● springiness ●● adhesiveness ●● cohesiveness ●● chewiness

Sensory attributes, including color, flavor, texture, sourness, saltiness, and overall acceptability using a 1–7 point scale (1 = dislike very much and 7 = like very much)

Wanangkarn et al. (2012)

TPA hardness ●● springiness ●● adhesiveness ●● cohesiveness ●● fracturability

The liking scores for overall liking, sourness, texture, and flavor using a nine‐point hedonic scale

Visessanguan et al. (2005)

TPA hardness ●● springiness ●● adhesiveness ●● cohesiveness

The liking scores of appearance, color, texture, taste, flavor, and overall liking using a nine‐point hedonic scale

Jittrepotch et al. (2015)

TPA hardness ●● springiness ●● adhesiveness ●● cohesiveness

The liking scores of appearance, color, texture, taste, flavor, and overall liking using a nine‐point hedonic scale

Riebroy et al. (2008)

TPA hardness ●● springiness ●● adhesiveness ●● cohesiveness ●● chewiness

The liking scores of appearance, color, aroma, flavor, taste, texture, and overall liking using a nine‐ point hedonic scale

Samakradhamrongthai et al. (2017)

6)  Durian chips

The hardness values (the maximum force required for compression) The crispness (the initial slope of the compression test) The number of force peaks in the compression test

The liking scores of color (yellow), puffiness, wryness, durian flavor, rancid smell, hardness, crispness, and overall preference using a nine‐point hedonic scale

Paengkanya et al. (2015)

7)  Broken‐rice based snacks (extruded)

Compression force

The liking scores of the attributes (color, crispness, flavor, and overall liking) using a nine‐point hedonic scale

Sriwattana et al. (2008)

Solid 1)  Mum (Thai fermented meat sausage prepared from minced beef, minced bovine liver and minced spleen) 2)  Nham (Thai fermented pork sausage)

3)  Plaa‐som a (Thai fermented fish product)

4)  Som‐fug (Thai fermented fish mince)

5)  Thai steamed dessert (Nam Dok Mai)

●●

●●

●●

●●

(Continued)

157

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11  Textural Characteristics of Thai Foods

Table 11.2  (Continued) Product

Texture analysis

Sensory

References

8)  T  hai cake (“Khanom Tan”)

Hardness and springiness, Puffiness of the cakes

the acceptability test of the product attributes (yellow color, springiness, puffiness, sweetness, and overall acceptance) using a nine–point hedonic scale

Jangchud et al. (2004)

TPA hardness ●● adhesiveness ●● gumminess ●● chewiness ●● springiness ●● cohesiveness Rheological properties using dynamic test in the frequency range of 0.01–100 Hz for G′, G″ and loss tangent.

–

Thaiudom and Pracham (2018)

Firmness and stickiness

Intensity of the firmness and stickiness using a 1–5 rating scale. Overall preferences and acceptability of the samples using a nine‐point hedonic scale.

Vatanasuchart et al. (2010)

1)  Coconut milk

Flow behavior

–

Simuang et al. (2004)

2)  Blueberry syrups

Rheological properties The viscosity of a sample of the blueberry syrup was measured as a function of shear rate and ranged from 2.5 to 62.5/s at 25 °C using a rotational viscometer with coaxial cylinder geometry on a small sample adapter and an SC4–29 spindle.

Sensory evaluation of the product with and without xanthan gum before and after storage for 16 weeks was performed using 30 untrained panelists for acceptance testing.

Pongsawatmanit et al. (2011)

Semi‐solid food 1)  J asmine rice pudding

2)  D  essert (Bualoy)

●●

Liquid

Note: Nine‐point hedonic scale: 1 = dislike extremely, 5 = neither like nor dislike, 9 = like extremely.

selected processed Thai foods. Nham (Figure 11.1g) is a typical food that can be found throughout the country. Nham is prepared from the mixture of minced pork to cooked pork rind (about 87%) and 13% of garlic, cooked rice, chili, salts, sucrose, erythorbate, tripolyphosphate, and monosodium glutamate (Visessanguan et  al. 2005). The

11.3  Selected Food Samples with Sensory Evaluation and Instrumental Measurement

restructuring and cohesiveness of nham was contributed from minced meat. Texture formation in the product is closely associated with fermentation in which the mechanism of binding in nham is an acid‐induced reaction (Visessanguan et  al. 2004). Restructuring effect and texture formation of nham probably involved slowly lowering the pH as a result of organic acid accumulation during fermentation. The decrease in pH gradually induces protein aggregation, leading to the ordered formation of protein structure, ­contributing to the firmness (Fretheim et al. 1985). In addition, acid solubilization of collagen was presumed (Aktas and Kaya 2001) by the weak acids enhancing the disruption of noncovalent intermolecular bonds that reinforce the collagen fibril structure. “Khanom tan” (Figure  11.1i), toddy palm cake, is a traditional Thai dessert prepared by steaming the fermented batter consisting of rice flour, sugar, salt, coconut milk, and palmyrah fruit pulp to yield a soft and spongy product (Rojanapaiboon 1989). Palmyrah fruit pulp contains yeast that ferments the batter to obtain the sponginess. Jangchud et al. (2004) evaluated the texture profile characteristics of Thai rice cakes prepared by mixing composite rice flour (different amylose contents), sugar, salt, coconut milk, sterilized palmyrah fruit pulp, yeast, and baking powder. The batter was fermented prior to steam for 15 minutes to obtain a spongy product. The test speed was set at 50 mm/min and the distance to compress sample was 60% strain using a 50 mm ­diameter compression cell for the hardness (N) and springiness (mm). Puffiness of the Thai rice cakes was measured in mm as the length from the top to the bottom of Thai rice cake. In addition, the acceptability test of the product attributes (yellow color, springiness, puffiness, sweetness, and overall acceptance) using a 9– point hedonic scale (1  =  dislike extremely; 5  =  neither like nor dislike; 9  =  like extremely) was performed. The amylose content of the composite flour decreased and the springiness and puffiness of the Thai rice cake decreased due to a loss in expandability of the batter after steaming. The ­optimum amylose and water contents in rice cakes provide the softness, puffiness, sweetness, and overall liking of the products rated as “like moderately.” However, without specifying the sample diameter and the height, the hardness represented by the force (N) and the strain represented by % has no meaning! Fruit syrups with different flavor, taste, color, and texture properties could be formulated using different sugars, acids, fruit flavors, fruit purée, and colorants, including polysaccharides. In the food industry, many types of polysaccharides are used in syrup as a thickening agent to modify the rheological properties of the products. Figure 11.2 showed the changes in viscosity of blueberry syrup stabilized by modified tapioca starch with and without xanthan gum during 16‐week storage at ambient temperature (Pongsawatmanit et  al. 2011). The sensory evaluation was performed using 30 untrained panelists for acceptance testing for the freshly prepared syrups and 16‐week stored samples using 9‐point hedonic scale. The results are shown in Figure 11.2. Adding xanthan gum could stabilize both the viscosity of the syrups and overall liking scores. For Thai fruit, especially the climacteric fruit (a stage of fruit ripening associated with an increase in ethylene production and respiration leading to ripening [Alexander and Grierson 2002]), the texture depends on the ripening stages. For example, the textural characteristics of mangoes exhibited a rapid decline in their behavior until the mangoes ripened. The decline became almost constant thereafter, indicating the completion of ripening. However, the rate of decline in textural

159

11  Textural Characteristics of Thai Foods

(a) 20000

Viscosity (mPa.s)

160

η = –18.73 t + 15493

15000

10000 η = –41.202 t + 13434 5000

0

0

50

100

150

Storage time (days)

(b) Xanthan substitution (%)

Storage (wk)

0

0

7.0± 0.5bc

7.0±0.6b

0

16

6.7± 0.8d

6.7± 0.6c

0.2

0

7.4± 0.5a

7.6±0.5a

0.2

16

7.3± 0.4ab

7.4±0.5a

Thickness liking

Overall liking

Mean ± standard deviation values followed by different lowercase letters within the same column are significantly (p 0.90. The large variation in chemical composition is mainly due to the variability in the ingredients used and the manufacturing process.

12.3 ­Organoleptic Quality Flavor, texture, and overall acceptability of laksa noodles have never been evaluated in any scientific report. Its presence is said to be insignificant as compared to the complex soup and soup garnishes served. From an informal survey done to those laksa fans, surprisingly we found out that no one has noticed the difference in the organoleptic quality of the laksa noodles, albeit the noodles were made differently with different ingredients. Overall, the laksa noodles are described to have a soft‐yet‐not‐mushy, and moderately firm with a bit springy and chewy kind of texture. The locals have adopted a texture descriptor from the Taiwanese, the “Q” texture, to describe texture of laksa noodles. The letter “Q” has been used to describe the texture of fish cakes, fish balls, tapioca

12.4  Textural Quality

starch balls, mochi (a Japanese word, sticky rice cake), and many more. The letter “Q” alone encompasses and represents a few texture parameters. Technically, when a food is said to be “Q,” it means the food is relatively firm with some degree of chewiness, but not too bouncy.

12.4 ­Textural Quality Textural profile analysis (TPA) parameters of laksa noodles were measured using a texture analyzer TA‐XT Plus (Stable Micro Systems, Surrey, UK), that was equipped with a 5 kg load cell. Two types of laksa noodles products were examined, one purchased from Penang manufacturer and the other purchased from Ipoh manufacturer. Both laksa noodles products were made of rice, with the former blended with tapioca starch and the latter blended with corn starch. Herein after these laksa products are known as Penang laksa noodles and Ipoh laksa noodles, respectively. Both laksa products looks similar, except Penang laksa noodles appear to be slightly translucent due to the use of tapioca starch and Ipoh laksa noodles are oily because this noodles product is coated with edible oil to prevent stickiness. The TPA methodology was done following the method stated in Bhattacharya et al. (1999) with some modifications. One strand of cooked noodle was fastened on the platform with adhesive tape and compressed to reach a 75% strain using a 36 mm cylindrical probe with a test speed and post‐test speed of 5.0 mm/sec. From the force‐ time plot, textural parameters of hardness (N) (maximum force at first compression peak), ­cohesiveness (no unit) (ratio of energies expanded in the second to the first compression after subtracting the elastic energy stored during biting), gumminess (N) (hardness × cohesiveness), springiness (no unit) (ratio of the maximum distance travel by the probe in second compression to that in the first compression), resilience (%) (percentage of recoverable energy in the first compression), and chewiness (N) (gumminess × springiness) were computed. Measurement were triplicated. In this work, effects of different sample preparation methods on textural quality of laksa noodles were examined. Prior to TPA, the noodles were pretreated with the ­following treatments before soaking in water at 90 °C for 5 or 10 minutes, drained and subjected to testing immediately within 2–3 minutes. Pretreatments: a) Direct soaking b) Scald for three seconds in boiling water before soaking c) Scald for three seconds in boiling water followed by cooling in running tap water (c. 25 ± 2 °C) for one minute before soaking All of these pretreatments were meant to imitate the common practices of laksa ­noodle preparation by the locals. From the manufacturer, the freshly made thick rice vermicelli had been cooked and can be consumed directly within 24 hours. If the noodles were not consumed within a day of production, the food stallers normally will scald the noodles in boiling water in a manner to cleanse it before used. Cooling in tap water is a gesture done hoping to induce retrogradation in order to restore some internal bonding to make the noodles firmer and chewier.

169

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Textural characteristics of the laksa noodles tested are tabulated in Table 12.1. Since the dimension of both noodle types before cooking are not significantly different with diameter values of 0.348−0.375 cm, comparison of mean values within the same textural variable is valid. Table  12.1 tabulates the as‐is textural parameters of both freshly prepared Penang laksa and Ipoh laksa noodles. Obviously, Ipoh laksa noodles appeared to be harder and showed higher cohesiveness, gumminess, springiness, chewiness, and resilience values when compared to Penang laksa noodles. No significant adhesiveness was detected between the two samples. Interestingly, the reverse is true after mild heat treatment. When the noodles were directly soaked in water at 90 °C for five minutes before testing, data collected (Table 12.2) showed that Penang laksa noodles were harder, gummier, and chewier than Ipoh laksa noodles. Apart from hardness, gumminess, and chewiness, other textural parameters values were not significantly different between the two types of samples tested. However, these differences in hardness, gumminess, and chewiness diminished with prolonged soaking in hot water for 10 minutes, as well as with scalding in boiling water for three seconds, with or without steeping in cold water. In terms of thermal stability, Penang laksa noodles are relatively more resistant to cooking than Ipoh laksa noodles. This can be evident from the degree of changes in hardness recorded before and after being directly soaked in hot water at 90 °C for 10 minutes. For Penang laksa noodles, the hardness values dropped from 14.00 N to 6.62 N, whereas for Ipoh laksa noodles’ hardness values changed from 18.03 N to 6.07 N, a total decrease of 52.71 and 66.33% was captured for the former and the latter, respectively. The data show that the two samples are fundamentally dissimilar. Although both samples are starch gels, the interactions at intermolecular, molecular‐supermolecular, and intersupermolecular levels may be different and account for the different textural behavior observed. What can be deduced from this simple experiment is that Ipoh laksa noodles (rice starch + corn starch) is much more prone to retrogradation than Penang laksa noodles (rice starch + tapioca starch). But, Ipoh laksa noodles is weaker in preserving its network structure, and thus its textural properties upon heat treatment, when compared to Penang laksa noodles. Nevertheless, all these differences vanished with high heat, and this answered why most consumers are not able to differentiate the textural difference between the two types of noodles, although they are made differently with different ingredients.

12.5 ­Factors Affecting Textural Quality of Laksa Noodles Laksa noodles are a product of starch gel that is prepared from high amylose flour and water. The rice flour is produced by wet‐milling. The milled rice is fermented by steeping in water for several hours, pressed, and molded into a dough, before steaming to pregelatinize partially the starch granules. The pregelatinized rice dough is then blended with other type of starches. Laksa noodles strands are formed by extrusion and cooked in hot boiling water. Typical laksa noodle processing is shown in Figure 12.2. Critical factors and significance of the processing steps on affecting textural quality of laksa noodles are briefly discussed below.

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12  Textural Characteristics of Malaysian Foods

Table 12.3  Microbial load (log CFU/g) of control and heat‐treated laksa noodles. Control

Heat Treated

TPC

Y&M

TPC

Y&M

0

ND

ND

ND

ND

3

5.30

5.09

ND

ND

7

6.09

5.91

ND

ND

14

6.37

6.26

2.85

2.84

TPC = total plate count; Y&M = Yeast and mold count. ND = Not detected, where the counts is less than 10 CFU/g.

Aged rice grain

water

Milling

Pressing

waste water

pressed cake

Steaming

Dough-forming

Kneading

Grinding + Mixing

Molding

starch water

Kneading

boiling water

Packing

Washing + Cooling

Cooking

Figure 12.2  Processing operation of laksa noodle.

In view of the absence of gluten, laksa noodles textural quality is highly dependent on the degree of cohesion in the starch matrix structure. Just like any other type of rice noodles, any factors that promote intermolecular forces, particularly hydrogen bonding, would promote a high degree of cohesion, which directly affects laksa noodles’ textural quality. The literatures reviewed that starch paste or gel properties are related to the relative degree of molecular chains interaction in the three‐dimensional network that was formed by retrograded solubilized amylose molecules with swollen starch granules embedded in between to effect a filled‐packed gel structure (Miles et al. 1985; Svegmark and Hermansson 1990, 1991, 1993).

12.5  Factors Affecting Textural Quality of Laksa Noodles

12.5.1  Rice Grain The amylose and amylopectin content of a rice grain is varied with the rice variety. The ratio of amylose to amylopectin within a starch granule is essential with respect to starch functionality in the noodles. This ratio not only will affect the architecture of the starch granule but will also affect its pasting properties and the physical and mechanical properties of the product made therefrom. Commonly, rice noodles are made from long‐grain rice with high amylose content (>25 g/100 g) (Juliano and Sakurai 1985). The effects of variation in rice physical and chemical properties on textural quality of rice noodles has been reported by Bhattacharya et  al. (1999), Hormdok and Noomhorm (2007), and Fari et al. (2011). It has been reported that rice varieties with high amylose content showed desirable noodle characteristics, because high amylose content is positively correlated with less stickiness, less cooking loss, higher swelling ratio, tensile strength, extensibility, and elastic recovery. Lu et al. (2009) reported that, in addition to the true amylose content, the super‐long chains in amylopectin of high amylose content rice starch may be the key factor that determines the retrogradation of amylopectin that eventually would affect the texture of starch gel. 12.5.2  Aged Rice Rice aging commences before and after harvest. It is a complicated process that involves changes in physical, chemical, and biological properties of a rice grain. These changes were found to affect the pasting and chemical properties of rice grain and thus the functionality of rice flour produced. Zhou et al. (2002) proposed that free phenolic acids released during the aging process will alter integrity of the cell wall as well as exert an antioxidant effect on the formation of free fatty acid that will complex with amylose during storage. As a result, the aged rice grains are resistant to grinding compared to freshly harvested rice grain. The lipid‐amylose complexes formed will limit starch granule swelling and reduce the capacity of the starch granules to rupture after cooking. 12.5.3  Milling Method Milling is a process that involves grinding polished rice kernels into rice flour. Wet milling is normally done by grinding rice kernels that have been soaked in water for hours with a double‐disc stone mill, whereas for dry milling dry rice kernels are ground using a metal grinder. According to Sorada and Noomhorm (2002), dry milling will result in a higher degree of starch damage, which will cause high cooking loss and soft texture to rice vermicelli made therefrom. 12.5.4  Particle Size of Rice Flour Large‐particle‐size rice flour tends to cause higher cooking loss and poorer textural quality of rice vermicelli. Sorada and Noomhorm (2002) recommended flour with particle size less than 200 mesh for producing rice vermicelli with acceptable cooking and textural quality. However, too small or too fine particle size may be indicative of a high degree of starch damage. Hatcher et al. (2002) stated that increased starch damage will cause the noodles to show undesirable high cooking loss and excessive surface swelling.

175

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12  Textural Characteristics of Malaysian Foods

12.5.5  Steaming Process After wet milling, rice flour will be recovered and pressed into a dough before being subjected to steaming. This steaming process is critical, as too long a steaming process will result in full gelatinization of rice starch. The dough will be too rigid for subsequent blending and extrusion. On the other hand, too short a steaming process may lead to insufficient gelatinization and the dough may be too friable. This may be due to not enough amylose leached out to assist the formation of a three‐dimensional network of the noodles. Preparation of a “well‐done” dough is always an experience‐intensive process. 12.5.6  Blending of Other Starch/Starches According to Fu (2008), approximately 5–25% of starches from other sources such as potato, corn, and tapioca are commonly added to enhance the textural quality of noodles products. Owing to a lower gelatinization temperature, rapid swelling, and high viscosity, these starches will impart soft yet chewy texture to the noodles. Addition of other starch molecules into rice starch networks is expected to decrease the molecular order or intermolecular interaction of the matrix. This may result in a plasticization effect that would reduce intensive localized stress concentration within the rice starch networks. This may then enhance the noodles’ dimensional stability, mechanical strength, as well as thermal stability. 12.5.7  Extrusion and Boiling Thick rice vermicelli noodles strands are different from thin ones by a bigger diameter of around 0.35 cm. Since the thick rice vermicelli is a ready‐to‐eat product, the boiling has to be well controlled to ensure adequate cooking. Overcooking will make the noodles mushy and unpleasant. Therefore, immediate cooling in cold water is essential to stop cooking. This cooling step not only serves to halt further cooking to the noodles but also allows the gelatinized starch molecules to trigger initial retrogradation, in order to restore some mechanical strength to facilitate subsequent handling. 12.5.8 Washing This washing step is meant to wash away soluble starches formed on the surface of the noodle. Some local laksa manufacturers perform washing several times to ensure the laksa noodles strands are stick‐free, whereas some opt to coat the noodles with cooking oil.

12.6 ­Storage Stability Laksa noodles are highly susceptible to microbial spoilage, due to the fact that they are highly moist in nature, with a water activity (aw) range of 0.91–0.93. Traditionally, this laksa noodle is packed in polyethylene (PE) bag and transported to the local wet markets or food stalls for sale. In the absence of proper packaging and suitable treatment, microbial growth is a serious cause of product deterioration. Thus, it has a short shelf life of not more than three days.

12.6  Storage Stability

Obviously, the keeping quality of laksa noodles is primarily dependent on the level of personal hygiene and food plant sanitation of the manufacturing premises. Personnel training, new machines, and good manufacturing practices need to be in place to ­revolutionize qualitative and quantitative production. Sadly, the effort and enthusiasm of local manufacturers in providing a facelift to the noodle industry is somewhat lackadaisical. In view of the high demand for fresh laksa noodles, there is a growing and urgent need for a simple and inexpensive process to preserve the noodles. An extended shelf life means an increased geographical market potential. A simple heating in pack experiment conducted in our laboratory involved partial vacuum packed 500 g of laksa noodles into nylon/PE bags and boiled in pack with three volume of hot water at 70 °C for 30 minutes. After heat treatment, the noodles were cooled immediately under running tap water. The noodles were then stored at 30 °C for microbial and textural quality observation. Results in Table 12.3 shows that the microbial quality of the laksa noodles has been improved tremendously upon a simple heat treatment. On day 14, yeast and mould counts for heat-treated samples had recorded a 2.84 log CFU/g whereas the control sample’s yeast and mould counts had reached to 5.09 log CFU/g on day 3. Referring to the Thai Industrial Standard for instant rice noodles (TIS 832-2005), the maximum acceptable yeast and mould counts is limited to ≤ 2 log CFU/g. From this, it is evident that pasteurization in pack is a promising and potential preservation technique to prolong shelf life of perishable fresh ready‐to‐eat laksa noodles. Besides looking at the microbial quality, the changes in textural quality upon heat treatment were examined. Results are shown in Figure 12.3. Interestingly, the noodles samples treated with pasteurize‐in‐pack were found to be significantly harder than the control sample by day 3, beyond which there is no significant difference. The increased hardness could be attributed to a more ordered network formed by pasteurize‐in‐pack treatment that involved the successive heating and cooling process. This pasteurize‐in‐ pack treatment evidently produced a noodle product that showed high consistency in textural quality.

60

Hardness (N)

55 50 45 40 35 30 0

3

7

14

Storage time (day) Control

Heat treated

Figure 12.3  Effects of heat treatment on hardness of laksa noodles. Data presented are average values of triplicate measurements. Circular cross‐section area and length of the tested samples are approximately 9.62 mm2 and 36 mm, respectively.

177

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12  Textural Characteristics of Malaysian Foods

12.7 ­Nutritional Quality 12.7.1  Gluten Free Since rice starch is considered hypoallergenic, the production of rice‐based noodles such as laksa noodles provides an alternative choice for celiac disease (CD) patients. With the absence of glutenin and gliadins in laksa noodles, occurrences associated with allergic responses to gluten can be avoided. Gluten sensitivity can lead to gas bloating, diarrhea, constipation, headaches, tiredness, and difficulty in concentration. In extreme cases, it can also lead to weight loss and poor nutrition. In Malaysia, the prevalence of CD is unknown, which could be underdiagnosed. Yap et  al. (2015) revealed that the seroprevalence of CD antibodies in healthy young adults in the Malaysian population was 1.25% (1 in 100), which is a seriously underdiagnosed situation. 12.7.2  Low‐Fat Carbohydrate Choice A typical 100 g serving of laksa noodles contains only small amounts of fats (0.0 g for Penang laksa and 0.9 g for Ipoh laksa). As a naturally low‐fat carbohydrate, laksa noodles can provide a filling base for a meal without the worry of overconsumption of fats; this could be beneficial for fat‐related disease patients. In addition, according to Panlasigui et  al. (1991, 1992), rice‐based noodles could be eaten by diabetic patients because it provides a lower glycemic index. This could be attributed to the retrograded starch molecules in the noodles, which serves as a source of resistant starch (Collado et al. 2001).

12.8 ­Conclusion The textural qualities of Malaysia laksa noodles products vary due to vast differences in formulation and production. Nevertheless, the distinction in textural quality between and/or among different products is hardly noticeable, because laksa lovers are so attracted to the irresistible taste, flavor, and aroma of the soups and garnishes, in addition to the network structure changes upon heat treatment. The keeping quality of laksa noodle products is not only determined by microbial deterioration but also by adverse textural changes occurring during storage as a result of starch retrogradation. Much remains to be done to produce shelf‐stable and ready‐to‐eat laksa products.

­Acknowledgments The authors are grateful to Mr. Lee Ping Wei, owner of HSB Laksa Marketing Sdn. Bhd. for sharing the information about laksa production. Besides, the authors would like to record their appreciation for the assistance rendered by Mr. Kwan Kok Kheen in obtaining the laksa samples.

­  References

­References Bhattacharya, M., Zee, S.Y., and Corke, H. (1999). Physicochemical properties related to quality of rice noodles. Cereal Chemistry 76 (6): 861–867. Collado, L.S., Mabesa, L.B., Oates, C.G. et al. (2001). Bihon‐type noodles from heat‐ moisture‐treated sweet potato starch. Journal of Food Science 66 (4): 604–609. Fari, M.J.M., Rajapaksa, D., and Ranaweera, K.K.D.S. (2011). Quality characteristics of noodles made from selected varieties of Sri Lankan rice with different physicochemical characteristics. Journal of the National Science Foundation of Sri Lanka 39 (1): 53–60. Fu, B.X. (2008). Asian noodles: history, classification, raw materials, and processing. Food Research International 41 (9): 888–902. Hatcher, D.W., Anderson, M.J., Desjardins, R.G. et al. (2002). Effects of flour particle size and starch damage on processing and quality of white salted noodles. Cereal Chemistry 79: 64–71. Hormdok, R. and Noomhorm, A. (2007). Hydrothermal treatments of rice starch for improvement of rice noodle quality. LWT‐Food Science & Technology 40: 1723–1731. Juliano, B.O. and Sakurai, J. (1985). Miscellaneous rice products. In: Rice: Chemistry and Technology (ed. B.O. Juliano), 569–618. St. Paul, MN: American Association of Cereal Chemists. Lu, Z.‐H., Sasaki, T., Li, Y.‐Y. et al. (2009). Effect of amylose content and rice type on dynamic viscoelasticity of a composite rice starch gel. Food Hydrocolloids 23: 1712–1719. Miles, M.J., Morris, V.J., Orford, P.D. et al. (1985). The roles of amylose and amylopectin in the gelation and retrogradation of starch. Carbohydrate Research 135 (2): 271–281. Panlasigui, L.N., Thompson, L.U., Juliano, B.O. et al. (1992). Extruded rice noodles: starch digestibility and glycemic response of healthy and diabetic subjects with different habitual diets. Nutrition Research 12 (10): 1195–1204. Panlasigui, L.N., Thomposon, L.U., Juliano, B.O. et al. (1991). Rice varieties with similar amylose content differ in starch digestibility and glycemic response in humans. American Journal of Clinical Nutrition 54 (5): 871–877. Sorada, Y.‐B. and Noomhorm, A. (2002). Effect of raw material preparation on rice vermicelli quality. Starch‐Stärke 54: 534–539. Svegmark, K. and Hermansson, A.M. (1990). Shear induced changes in the viscoelastic behaviour of heat‐treated potato starch dispersions. Carbohydrate Polymers 13 (1): 29–45. Svegmark, K. and Hermansson, A.M. (1991). Distribution of amylose and amylopectin in potato starch pastes – effects of heating and shearing. Food Structure 10 (2): 117–129. Svegmark, K. and Hermansson, A.M. (1993). Microstructure and rheological properties of composites of potato starch granules and amylose – a comparison of observed and predicted structures. Food Structures 12 (2): 181–193. Yap, T.W.C., Chan, W.K., Leow, A.H.R. et al. (2015). Prevalence of serum celiac antibodies in a multiracial Asian population‐a first study in the young Asian adult population of Malaysia. PLoS One 10 (3): e0121908. https://doi.org/10.1371/journal.pone.0121908. Zhou, Z., Robards, K., Helliwell, S. et al. (2002). Ageing of stored rice: changes in chemical and physical attributes. Journal of Cereal Science 35: 65–78.

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13 Textural Characteristics of Australian Foods Andrew Halmos, Lita Katopo, and Stefan Kasapis School of Science, RMIT University, Bundoora West Campus, Melbourne, Victoria, Australia

13.1 ­Introduction Australia is a relatively new country. Its history spans only 230 years for the majority of the population (Macintyre 2009). As far as the cuisine is concerned, the aboriginal ­people and culture have had very little influence on the eating habits of the current population, but there are signs that this state of affairs may be changing in the not too distant future. Australia is a European culture, and it has been dominated primarily by British and Irish eating habits. In this sense, the terms used and often the expectations have been similar to Western culture and more specifically the British/Irish culture (Santich 2011) but, as it will be discussed, the multicultural immigration program is increasingly shaping up a considerable diversification of the cuisine in Australia. Pre– and immediately post–World War II, the standard food was a piece of meat, often lamb, beef, or chicken, with three boiled vegetables and ice cream or sponge cakes for sweets. The standard drink was white tea. Restaurants were few and far between, and take away meals were limited to fish and chips and the odd hamburger. Asian foods were very rare and until recently were limited to Cantonese cuisine (Bonner 2015). Restaurants were based in large hotels catering to tourists or businessmen, and food was basically steak or roasts with potato and vegetables. Salads were not very common, and sweets were simple cakes, pavlovas, and fruit salad with ice cream. With the relocation of postwar economic migrants and refugees, however, this changed significantly. The southern and eastern European influence brought in their dishes, as well as some of the spices, ingredients, and condiments used in the Mediterranean shores and the countries of the ex‐Soviet sphere of influence in Europe (Wells 2015). For instance, sour cream was once considered cream that had gone off, but now is a standard ingredient in most homes used to make sauces, dips, flaky pie crusts, and so on (Born 2013). In the major cities in Australia, restaurants cover the whole spectrum of cuisines from around the world. The Asian influence is unmistakable in today’s culture. The last few years have seen the increase in popularity of Japanese, Thai, Vietnamese, Indian, and Malaysian cuisines alongside Cantonese and mildly spicy

Textural Characteristics of World Foods, First Edition. Edited by Katsuyoshi Nishinari. © 2020 John Wiley & Sons Ltd. Published 2020 by John Wiley & Sons Ltd.

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13  Textural Characteristics of Australian Foods

Chinese food. From North America, Mexican food has become popular and Middle Eastern delicacies are also abundant (Finkelstein 2003). All this goes to illustrate that Australia has accepted and expects to try and enjoy food from around the world. Not only are European cuisines represented, but so are major Asian cuisines, and significantly, most of them are available as take‐out food, which supports our increasingly fast‐paced lifestyle. The globalization of markets has also allowed a bewildering array of canned and packed foods and ingredients to become available on the shelves of large supermarket chains and smaller convenience stores. This now encourages the meals to be prepared at home and the average household, especially of the more “adventurous” young to middle age groups, is willing to try all the dishes from sushi to stir fry, pizza, and borscht. However, dishes produced in Australia are based on their own variety of ingredients, which are locally sourced. In several cases, this creates a desirable variation on the original dish, differing in its flavor and texture (State Library of South Australia 2006). The multicultural nature of Australia contributes to its Lucky Country tag (Horne 1964). Not only does it have an enormous variety of fresh clean ingredients that can be produced locally, but it imports almost all the other ingredients from around the world. This allows for every cuisine to be available to be consumed and the Australian psyche and curiosity has created a culture where all the dishes are tried by the Dinky‐Dye (i.e. traditional) Aussie.

13.2 ­Importance of Mouthfeel and Its Recognition In the early days, the sensory expectation was limited to flavor components. The ­textural aspects were of secondary concern, since it was difficult to appreciate the inexorable connection and importance of the two concepts to maintaining the overall consistency of food. This is clearly illustrated by the well‐known Australian meat pie (originally a foreign import). This is a pastry that houses a meat stew. The general expectation was to have a crisp pastry and a thick‐sauced hot meat stew. The contradiction came when tomato sauce was added onto the top and sometimes into the body of the pie, which destroyed the crispy nature of the pastry. It has now become soggy in this variation and almost impossible to control when eating from the hand. The result is spillage onto the clothing of the consumer. This has almost been accepted to be the norm when eating these types of products! In Adelaide, the meat pie was taken to another level, where it was dropped into a hot pea soup, called the pie floater (Clarkson 2013).

13.3 ­Developments in Mouthfeel and Texture Terms With the new cuisines from all over the world being accepted, new textural aspects are also being introduced and gradually accepted. There is an increasingly recognizable consumer push to identify the major textural characteristics of food as a driving force for increasing likelihood of taste acceptance. Flavor release, which often can be ­controlled by the low melting point of the products (e.g. in gelatin‐based materials), can have inherent textural ramifications (Guichard 2002; Reineccius 2017), but it is not

13.4  Typical Meals with Descriptors for the Australian Palate

Table 13.1  Common texture terms and the associated food type and meaning. Term

Food type

Meaning or usage

Tough

Meat

Hard and difficult to chew.

Soft or tender

Meat

Easily chewed, “melt in the mouth.”

Crunchy

Vegetables, fruit, or sweets

Element of hardness with audible sound during mastication. The product is often dry.

Crispy

Vegetables, fruit, or baked products

Similar to crunchy, but with an element of freshness especially for vegetables.

Sloppy

Pastry or vegetables

Wet or soggy. Opposite to crunchy.

Chewy

Meat

Elastic and unyielding.

Slimy

Vegetables

Smooth, oily, and mucous‐like surface.

Leathery

Meat

Difficult to chew, elastic, and hard to penetrate.

Rubbery

Meat

Too elastic and hard to penetrate.

Brittle

Sweets

Easily broken.

Lumpy

Pastes, sauces

Inhomogeneous with undesirable lumps.

Creamy

Pastry, sauces

Smooth flowing, high degree of lubrication, highly viscous with a milky flavor.

Fatty

Pastry, sauces

Smooth flowing, high degree of lubrication, highly viscous with an animal flavor.

Greasy

Pastry, sauces

Smooth flowing, high degree of lubrication, highly viscous with an animal fat feel.

Smooth

Sauces

Homogeneous.

Sticky

Sauces, lollies

Adherence to the tongue or palate.

Thin or watery

Sauces, soups

Low viscosity.

Thick

Sauces, soups

High viscosity.

always easy for the consumer to make the connection. Texture terms must be further developed in the Australian culture. In addition, Table 13.1 describes mouthfeel that is often related to the solid foods and details the food(s) that is/are associated with each texture term.

13.4 ­Typical Meals with Descriptors for the Australian Palate The basic mouthfeel desired by the Australian palate is due to the fat component of most of the elements making the final formulation. Fat not only carries a large portion of the flavor component of foods but also creates and supports the mouthfeel, which allows the lubrication and mastication of the foods used in Western culture (Sanders 2016). While some dishes such as salads contain low fat level, the salad dressings are often fat or oil based, including mayonnaise, French and Italian dressings, and other condiments (García‐Casal et al. 2016).

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13.5 ­Breakfast 13.5.1  Toasted Bread This is used to provide a vehicle for either butter with cheese, cold cuts, jam, Vegemite, or peanut butter as topping, or as a hot meal type addition (Figure 13.1). The toast has to be crisp and dry with a smoky flavor. The toppings provide the variety and flavor contrast. The hot meal additions could be eggs, hot baked beans, or hot spaghetti with tomato sauce. 13.5.2  Cereals with Milk This is based on the corn flakes or puff clusters type dish, which often has cold milk added to it (or sometimes hot milk) and possibly cut‐up raw or dried fruit. It is eaten quickly to avoid the dreaded sogginess setting in! The cereal is often preferred crunchy (Sumithra and Bhattacharya 2008) with the sweet flavor of the fruit or honey providing the taste. Weet‐Bix is one of the most popular cereals in Australia (Mullan et al. 2014). It is made from layers of wholegrain wheat flakes pressed together and then baked in the form of a biscuit. The biscuit is typically served with milk (hot or cold) and consumed, as mentioned earlier, promptly before sogginess occurs.

Figure 13.1  Vegemite spread on toast.

13.5 Breakfast 400 Weet-Bix

350 300

Force (N)

250 200 150 100 Lamington

50 0

0

20

40

60

80

100

% Deformation

Figure 13.2  Force‐deformation profiles for Weet‐Bix and Lamington at ambient temperature with a compression rate of 1 mm/s. The dimensions for Weet‐Bix and Lamington are 80 × 40 × 15 mm and 60 × 60 × 35 mm, respectively. Weet‐bix and Lamington, with heights of 15 and 35 mm respectively, are placed on an aluminum platform and compressed using a cylinder probe with 100 mm in diameter.

Texture profile analysis under compression testing is a valuable tool for assessing the textural characteristics of solid‐like food products, including cereals. Figure  13.2 ­demonstrates the texture profile analysis of Weet‐Bix at ambient temperature using a compression rate of 1 mm/s. It is shown that a sizable force of around 338 N (maximum force) is needed to deform the sample. Furthermore, the jagged curve observed in the Weet‐Bix profile, which argues for a crunchy texture, is attributed to the heterogeneous nature of the biscuit, since this is an assortment of numerous wheat flakes. Each peak on the curve refers to the fracture of more‐or‐less a single flake. 13.5.3 Coffee This drink can be taken with or without the addition of milk and/or sugar. It is expected to be a hot and refreshing beverage, sometimes of a very strong or bitter flavor. Freshly brewed coffee such as espresso, long black, macchiato, cappuccino, latte, and flat white are generally consumed in cafés. The espresso is a straight shot of coffee with a strong flavor. A double shot of espresso combined with hot water is called long black. The macchiato, latte, cappuccino, and flat white are composed of espresso and milk (Hurwood 2016). The flat white is considered as an Australian icon and this is prepared by pouring steamed milk over a shot of espresso. Such milk ­commonly has a thin layer of foam contributing to a slight creamy mouthfeel. Although there are many types of freshly brewed coffee, the instant variety (e.g. Nescafe by Nestlé) still dominates the market due to its affordability, convenience, and long shelf‐life (Adams 2013). Black tea or English breakfast tea is also popular and would be of a similar descriptor.

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13.5.4  Fried Tomatoes The tomato is initially cut into two parts, sprinkled with salt and pepper, and then fried next to sausages, served hot. It has a soggy and soft mouthfeel with a trace of caramelized flavor. Herbs like rosemary are often added on top of the fried tomato to enhance the flavor. This is based on the English breakfast concept. 13.5.5  Steak, Sausages, or Chops Like fried tomato, these are part of the English breakfast. One or more pieces of fried meat are used, which should provide a good mouthful to chew, but should not be elastic – rather, it should be an easily chewable piece of meat. 13.5.6 Eggs A wide variety of preparation is commonly accepted (i.e. poached, fried, sunny‐side up, or scrambled). Eggs should be soft and if fried, slightly raw in the yoke. They may be placed on top of a piece of freshly toasted piece of bread. Salty flavor should be present, which besides the common table salt, is sometimes achieved with a dollop of Vegemite. 13.5.7 Bacon The meat product usually comes from the belly and loin of pork, which is sliced, cured with salt (e.g. sodium chloride), and smoked (Sheard 2010). A healthier version, called short‐cut bacon, has become increasingly popular due its lower fat level, as compared to the original bacon. The short‐cut bacon is derived mostly from pork loin cuts with a lower fat content. Bacon is generally fried to a crispy consistency around the edges, producing a smoky flavor. 13.5.8 Spreads Vegemite is a product of Kraft Foods Ltd., but is manufactured in Port Melbourne in the State of Victoria, and is used as a flavor enhancer. It is a leftover brewers’ yeast extract, black spread, which has a beefy, astringent flavor and a butter‐like spreadable texture (Figure  13.1). If the product is not butter‐like, it is perceived as lacking the vitamin content. The spread is often added to buttered toast or eggs and can be used for snacks on buttered crackers (Richardson 2003). Peanut butter, which is basically made from crushed peanuts, can be stabilized or unstabilized (Gills and Resurreccion 2000). Both varieties are available in the market. Hydrogenated oils (e.g. palm oil), hydroxypropyl methylcellulose, and methylcellulose are examples of stabilizers used in peanut butter (Tanti et al. 2016). The spreads that are stabilized do not separate into an oil phase. Peanut butter is a high‐protein spread that can be smooth or crunchy, depending on whether uncrushed peanut pieces are added to the smooth paste (Carreau et al. 2002; Co and Marangoni 2012; Robins 2000). It is often eaten on bread or toast. Texture is expected to range from a smooth oily sensation to a dry mouthfeel with some adhering to the roof of the mouth.

13.6  Lunch or Mid‐Day Meal

13.6 ­Lunch or Mid‐Day Meal 13.6.1  Sandwiches with Fillings Cold meats are now the accepted form of creating and enjoying sandwiches. The use of ham, salamis, and cold cuts is expected to produce a variety of chewable meats on a range of breads with many herbs and spices included. Meat sandwiches could include cheese slices, and possibly lettuce, tomatoes, or other salad ingredients as well. This is a composite system with a complex texture, where the meat provides the chewing needs, the cheese gives the fatty mouthfeel, and the salad offers the cold and crispy sensation. Straight salad fillings include a whole gamut of ingredients, and the expected mouthfeel is a cold, crispy nature with the dominating sensation of eating raw, fresh vegetables. 13.6.2  Pie, Sausage Roll, or Pastry These are various pastries covering cooked meat or vegetables, which are eaten with tomato sauce as condiment and sometimes accompanied by fried chips. They are expected to be hot and the pastry to be flaky or crispy. The inside is expected to require some chewing. 13.6.3  Potato Products These are mainly potato chips served hot, having been deep fried in oil. They should not be very oily, but crunchy, easily chewed, and salty in flavor (Pedreschi et al. 2016). To provide an acidic flavor, a small amount of vinegar is often poured on top. On the other hand, mashed potatoes are boiled potatoes, which are crushed with some milk and/or butter (Fernández et al. 2006). They provide a soft, basic food accompaniment to meat, which often has a sauce or gravy associated with it. A third variant is baked potatoes, which is a washed potato that is placed in the oven and allowed to bake. It should have a soft texture in the interior with a slightly crispy exterior. The product is often eaten with a dollop of butter or margarine, though in recent times, sour cream or cheese sauces have become common toppings. 13.6.4  Boiled or Steamed Vegetables These vegetables provide the traditional accompaniment to meat. They should remain crispy after a rapid and short boiling or steaming session (as a measure of retaining the vitamin levels) and provide a flavor contrast to the meat. One suspects that a contrast in texture may also be sought, though rarely articulated. 13.6.5  Vegetables with Roux These are European style vegetables, which are braised with a small amount of oil and flour. The mixture of oil and flour, known as roux, is utilized to thicken white sauces (e.g. béchamel), thereby enhancing the flavor. The mouthfeel, of course, is now dominated by the sauce and not the crispy nature of the steamed vegetables.

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13.6.6  Salads and Dressings These are consumed to accompany the modern main meal, regardless of the time of the day. They are raw, cold, and diced vegetables (e.g. tomatoes, celery, lettuce, and onion) and often have the dressings added. The dressing provides flavor while the vegetables give the cold, crispy, and crunchy texture. The oil base of the dressing also allows the viscous material (emulsion) to flow over the palate, which is a desirable sensation. Potato salad with mayonnaise dressing is also popular. The boiled potato provides a mouth‐filling sensation while the cold, slippery salad dressing gives a cold and refreshing mouthfeel. 13.6.7 Meat The slice of meat, which forms the centerpiece of the meal, is often barbequed, especially in the long, warm summer days. This provides a great central focus to an outdoor venue. The meal is then a piece of barbequed meat (chops, steak, or sausages) with salad and perhaps a roast potato or grilled mushroom. This may be served at lunch or dinner time.

13.7 ­Dinner 13.7.1 Soup Soup is generally consumed in the beginning of a meal, i.e. prior to the meat dishes. The bulk of the soups are vegetable based (e.g. pumpkin, peas, carrot, and broccoli), which is often prepared with chicken stocks. In some cases, meat pieces such as bacon, ham, or chicken are added into the soups. The soup is expected to be served hot throughout the year, with or without meat or pasta, and exhibits usually a thick and rather creamy consistency. 13.7.2  Meat in the Form of Chops or Steak Different meats such as beef, emu, buffalo, or kangaroo steak can be used in the main part of the meal. The most common is beef steak and is expected to be chewable, not elastic, and to some degree dry, rather than fatty. Grilling temperature contributes to different degrees of rawness. A rare steak is characterized with a soft texture and a red‐colored center while the well‐done counterpart has a brown, fully cooked center. Lamb chops are often well done, while beef steaks are more often rare or medium‐rare. Meat with less fibrous texture (like a beef fillet) are more desirable as rare steak. The exotic meat varieties (game meat like venison) tend to be a little tougher and provide slightly different taste but the texture is not differing greatly. 13.7.3 Seafood The whole range of seafood is consumed, mostly in restaurants. Crab, lobster, oyster, abalone, and other seafood are consumed either in the European manner (e.g. deep fried or grilled) or the Asian manner (e.g. stir‐fried with sauces). Oysters are often

13.7 Dinner

eaten raw with a drop of lemon juice. Everything from prawns to octopus is available and popular in Australia although it tends to be quite pricy compared to pork chops or beef steaks. 13.7.4 Fish Salt‐water or fresh‐water fish is often grilled or pan fried. Examples of fish widely ­consumed in Australia are barramundi, salmon, tuna, snapper, trout, flathead, and whiting. The fish provides a very subtle flavor and a soft, flaky and smooth mouthfeel. The fatty component of the mouthfeel is provided by a small amount of butter on the surface or some complimentary sauce such as tartar or mayonnaise. 13.7.5 Rice There are many types of rice grown in Australia, e.g. Japonica, Indica, Amaroo, Millin, Langi, and Koshihikari, with Japonica being the most abundant. Amaroo, Japonica, and Millin are medium‐grain varieties while Indica and Langi are long‐grain varieties. The Koshihikari, which is a short‐grain variety, is suitable for Japanese cuisine due to its adhesiveness (Department of Agriculture and Water Resources 2015). The surface of rice is expected to be clean, almost dry, and the rice particles should be individual. The individual particles produce a smooth, granular mouthfeel. Basmati, a long, slender‐ grained aromatic rice, is also popular in Australia (e.g. in fish, chicken, tomato, and coconut curry dishes). 13.7.6 Vegetables The texture of vegetables should be crunchy and fresh, and they are expected to be warm to hot, having been boiled, steamed, or stir‐fried very quickly, but they can also be consumed raw. Herbs and spices are sometimes added to the vegetables to give extra flavor. Asparagus, broccoli, beetroot, carrot, cabbage, lettuce, cucumber, zucchini, and fennel are examples of typical Australian vegetables (Muir et al. 2007). 13.7.7  Chinese‐Style Food In Australia, Cantonese is the prevalent cuisine, which utilizes poultry, fish, pork, fresh vegetables, and fruits. Examples are dumplings, steamed fish, stir‐fried leafy vegetables, and noodles in soup. Dim sum is an example of Chinese‐style brunch where small portions of food are prepared in small plates or steamer baskets made from bamboo. Steamed dumplings (filled with either prawn of pork), steamed buns (commonly filled with barbequed pork), spring rolls (a fried roll with vegetables), and rice porridge are some prominent dim sum dishes. A derived form of the dim sum dumpling, also known as dim sim or dimmy, was developed in Australia in 1940s (Brown 2016). It is a dumpling made from minced pork meat and vegetables wrapped in a thick, crispy skin/pastry. The pastry used for dim sim is larger and thicker than that of the dim sum counterpart. It is a popular snack in Australia and can also be found in fish and chip shops.

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13.7.8 Cheeses The dominant natural cheese in Australia is the cheddar, based on the English version and includes the semi‐matured and matured (tasty) cheddar cheeses. It is made from bovine milk, as is the bulk of the cheeses (Sutherland 1998). Australian cuisine, h ­ owever, now accepts and increasingly enjoys the full range of cheeses from Europe, including goat and ewe (e.g. feta of Greece and Roquefort of France) and the full variety of Italian, French, and Central European varieties. Processed cheeses are generally made using different types of natural cheeses, with cheddar being the major ingredient. They are widely popular for children’s sandwiches or take‐out sandwiches, often due to their convenience (Wang et al. 2011). 13.7.9 Sweets Pavlova is a dry sugar meringue that provides a crispy, sweet, and crunchy mouthfeel. It is often filled with sweet whipped cream and cut‐up fruit, as illustrated in Figure 13.3. Recently, Pavlova variants based on either chocolate or fruit‐incorporated pastries have become increasingly popular. Pavlova pastry needs to be very flaky and soft, with the cream being highly aerated and viscous. The mouthfeel is a combination of the highly viscous, lubricating sensation of the sugar meringue and the flaky, moist but fat‐free wiping sensation of the sponge. The mouthfeel can be compared to a very soft bath sponge being gently wiped across the palate. Lamingtons is a sponge cake coated with a layer of chocolate and then covered with desiccated coconut. This Queensland‐originated cake is served in relatively small cubes and has a soft, creamy, and fluffy texture (Santich 2012). The textural features are shown in the force‐deformation profile of Lamingtons where the cake exhibits a smooth curve due to its homogenous nature (Figure 13.2). Texture profile analysis at a compression rate of 1 mm/s gives Lamingtons a maximum force of about 91 N arguing for a soft and/or fluffy texture, which is in stark contrast to the crunchy Weet‐Bix with 338 N of maximum force under compression testing (also in Figure 13.2).

Figure 13.3  Pavlova with strawberry and kiwi fruits.

­  References

13.7.10  Ice Cream A variety of ice‐creams are often consumed as sweet to provide a strong flavor with a cold sensation to clean the palate. The ice cream may be cream based, which provides the highly viscous fatty sensation, or water‐based gelato with a strong fruit flavor but less viscous cleansing sensation. A softer creamy ice cream texture can be obtained by incorporating more air into the food matrix (Goff and Hartel 2013). The ice cream is then able to melt faster and provide a faster delivery of the flavor across the tongue, thereby creating an impression of a higher flavor incorporation. The intensity of flavor delivery at mouth temperature is a highly sought characteristic. 13.7.11 Snacks A wide range of snacks are very common, especially for social occasions where finger foods are typically served. They can be quite exotic, such as sushi, fried calamari or satays. Beside those, dry biscuits can be available for dips based on chickpeas (humus), yogurt (tzatziki), chili, tomato sauce (salsa), avocado, or simply a cheese spread based on Philadelphia cream cheese or something similar. At these occasions, the important sensory aspect sought is strong flavor intensity and a rough mouthfeel. The contrast between the scratching sensation from the biscuit, a potato crisp or nuts and the smooth, lubricated slippery feel of the dip is expected in these dishes, hence determining their appeal.

13.8 ­Conclusions Australian cuisine reflects the dramatic changes in its society over the last 230 years, since the arrival of the First Fleet at Sydney in 1788. It has been dominated by the British eating habits especially in domestic cooking, with roast dinners and the take‐out food fish and chips remaining hugely popular. Subsequent waves of immigration from the rest of Europe and the shores of the Mediterranean brought with them sophisticated food cultures that further developed the Australian cuisine. Barbeque meat is a local tradition and served with a fabulous variety of rich and nutritious dips, breads, salads, and fruits. Recent waves of multicultural immigration from South East and South Asia, India, and China are establishing a strong base of interest in Asian and Oriental‐style recipes and cooking methods. It is anticipated that the widespread availability of organic and biodynamic foods will revive the interest in bush food based on a unique native flora and fauna that sustained Indigenous Australians in the precolonial society.

­References Adams, J. (2013). Australia’s American coffee culture. Australasian Journal of Popular Culture 2: 23–36. Bonner, F. (2015). The mediated Asian‐Australian food identity: from Charmaine Solomon to MasterChef Australia. Media International Australia, Incorporating Culture & Policy 157: 103–113.

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Born, B. (2013). Cultured/sour cream. In: Manufacturing Yogurt and Fermented Milks, 381–391. Wiley. Brown, S.L. (2016). Dim sims: The history of a Chinese‐Australian icon, viewed 4 October 2017, www.abc.net.au/news/2016‐02‐08/dim‐sim‐invention‐a‐story‐of‐chinese‐ australian‐history/7148450. Carreau, P.J., Cotton, F., Citerne, G.P., and Moan, M. (2002). Rheological properties of concentrated suspensions: application in foodstuffs. In: Engineering and Food for the 21st Century (eds. J. Welti‐Chanes, G. Barbosa‐Canovas and J.M. Aguilera), 372–345. New York: CRC Press. Clarkson, J. (2013). Food History Almanac: Over 1,300 Yeras of World Culinary History, Culture, and Social Influence. Lanham, Maryland: Rowman & Littelfield. Co, E. and Marangoni, A.G. (2012). Organogels: an alternative edible oil‐structuring method. Journal of American Oil Chemists’ Society 89 (5): 749–780. Department of Agriculture and Water Resources (2015). Rice, Australian Government, viewed 5 October 2017, www.agriculture.gov.au/ag‐farm‐food/crops/rice. Fernández, C., Dolores Alvarez, M., and Canet, W. (2006). The effect of low‐temperature blanching on the quality of fresh and frozen/thawed mashed potatoes. International Journal of Food Science & Technology 41 (5): 577–595. Finkelstein, J. (2003). The taste of boredom: McDonaldization and Australian food culture. American Behavioral Scientist 47 (2): 187–200. García‐Casal, M.N., Peña‐Rosas, J.P., and Gómez‐Malavé, H. (2016). Sauces, spices, and condiments: definitions, potential benefits, consumption patterns, and global markets. Annals of The New York Academy of Sciences 1379: 3–16. Gills, L.A. and Resurreccion, A.V.A. (2000). Overall acceptability and sensory profiles of Ustabilized Peanut butter and Peanut butter stabilized with palm oil. Journal of Food Processing and Preservation 24 (6): 495–516. Goff, H.D. and Hartel, R.W. (2013). Ice Cream. Boston, MA: Springer US. Guichard, E. (2002). Interactions between flavor compounds and food ingredients and their influence on flavor perception. Food Reviews International 18 (1): 49–70. Horne, D. (1964). The Lucky Country: Australia in the Sixties. Ringwood, Victoria: Penguin. Hurwood, J. (2016). Coffee Types Explained, www.canstarblue.com.au/appliances/kitchen/ espresso‐coffee‐machines/coffee‐types‐explained. Macintyre, S. (2009). Beginnings. In: A Concise History of Australia, 3rde, 1–15. Cambridge: Cambridge Concise Histories, Cambridge University Press Cambridge Core database. Muir, J.G., Shepherd, S.J., Rosella, O. et al. (2007). Fructan and free fructose content of common Australian vegetables and fruit. Journal of Agricultural and Food Chemistry 55 (16): 6619–6627. Mullan, B., Wong, C., Kothe, E. et al. (2014). An examination of the demographic predictors of adolescent breakfast consumption, content, and context. BMC Public Health 14: 264. Pedreschi, F., Mariotti, M.S., and Cortés, P. (2016). Chapter 15 – fried and dehydrated potato products. In: Advances in Potato Chemistry and Technology, 2e (eds. J. Singh and L. Kaur), 459–474. San Diego: Academic Press. Reineccius, G. (2017). Aroma encapsulation and controlled delivery. In: Springer Handbook of Odor (ed. A. Buettner), 261–270. New York: Springer.

­  References

Richardson, K. (2003). Vegemite, Soldiers, and Rosy Cheeks. Gastronomica 3: 60–62. Robins, M.M. (2000). Lipid emulsions. Grasas Y Aceites 51: 26–34. Sanders, T.A.B. (2016). Introduction: the role of fats in human diet. In: Functional Dietary Lipids – Food Formulation, Consumer Issues and Innovation for Health (ed. TAB Sanders), 1–17. Cambridge, UK: Elsevier. Santich, B. (2011). Nineteenth‐century experimentation and the role of indigenous foods in Australian food culture. Australian Humanities Review 51: 65–78. Santich, B. (2012). Bold Palates: Australia’s Gastronomic Heritage. Kent Town, South Australia: Wakefield Press. Sheard, P.R. (2010). Bacon. In: Handbook of Meat Processing (ed. F. Toldrá), 327–336. Hoboken, NJ: Wiley. State Library of South Australia (2006). Pie floater, www.samemory.sa.gov.au/site/page. cfm?u=269. Sumithra, B. and Bhattacharya, S. (2008). Toasting of corn flakes: product characteristics as a function of processing conditions. Journal of Food Engineering 88 (3): 419–428. Sutherland, B. (1998). Developments in cheese science and technology in Australia. Australian Journal of Dairy Technology 53 (2): 63–66. Tanti, R., Barbut, S., and Marangoni, A.G. (2016). Oil stabilization of natural peanut butter using food grade polymers. Food Hydrocolloids 61 (Supplement C): 399–408. Wang, F., Zhang, X., Luo, J. et al. (2011). Effect of proteolysis and calcium equilibrium on functional properties of natural Cheddar cheese during ripening and the resultant processed cheese. Journal of Food Science 76 (3): E248–E253. Wells, K. (2015). Australian food and drink, Australian Government, viewed 2 October 2017, www.australia.gov.au/about‐australia/australian‐story/austn‐food‐and‐drink.

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14 Textural Characteristics of Indian Foods A Comparative Analysis Amardeep Singh Virdi and Narpinder Singh Department of Food Science and Technology, Guru Nanak Dev University, Amritsar, Punjab, India

14.1 ­Introduction Wheat is milled into flour/meal and processed into various products. The quality of raw and intermediate products (flour/meal) greatly influences the textural, rheological, and sensory characteristics of end products. Therefore, the rheological and textural attributes of the raw and intermediate products need explanation and prediction on a scientific level. The understanding texture of food must be evaluated in terms of fracture and rheological behavior, oral physiology, structure, friction forces, and expectations of food. The knowledge of chemistry (nature of bonds), physics (acoustics), physiology (oral processing), and psychology (perception of texture) is required to evaluate the texture of food. Szczesniak (2002) described the texture of the food as “the sensory and functional manifestation of the structural, mechanical, and surface properties of foods detected through the senses of vision, hearing, touch, and kinesthetics.” Textural properties (hardness, springiness, gumminess, stickiness, chewiness etc.) of dough and baked products while for flour/meal, pasting properties are evaluated. Wheat flour is constituted of starch, gluten, and nongluten proteins as major proportion, wherein gluten proteins represented 80% of wheat proteins. The nongluten ­forming proteins (i.e. albumins and globulins) are soluble in water and in dilute salt ­solution and generally have a molecular weight of 80 (Panghal et al. 2017). Wheatmeal with higher levels of DMS yielded superior quality chapatis with a high score of textural attributes (Prabhasankar et al. 2002). Wheat milled in a stone mill gave better‐quality chapatis, as compared to hammer‐, disk‐, pin‐, and roller‐milled flour, which have been attributed to the fairly higher levels of DMS in flour (Inamdar et  al. 2015). Rao et  al. (1989) showed that the levels of DMS significantly ­correlated to gluten strength and WA of dough, cohesiveness, and adhesiveness of chapatis made from wheat flour meal. The softness, pliability and overall acceptability score of chapatis increased after treatment of dough with xylanase, bacterial and fungal α‐amylase, and the combination of amylases and xylanase enzymes of different origins. Enzymatic treatment of dough resulted in the conversion of amylose, amylopectin, and highly complex arabinoxylans into simple reducing sugars, thus enhancing the texture and sensory properties (Hemalatha et al. 2010; Hemalatha et al. 2013). There is significant correlation between GHI and extensibility, pliability, and puffing height of chapati; however, GHI and chapati overall acceptability score poorly c­ orrelated with each other. Chapati moisture, puffing height, pliability, and extensibility incrased with an increase in DMS; however, very high levels of DMS in meal led to an increase in dark spots on the surface of chapati. The reducing sugars in DMS easily burn during baking, which increase the number of dark spots (Kundu et al. 2017). The ­mixing of purified arabinoxylans, obtained from good chapati‐making wheat flour, enhanced the textural and sensory quality and overall acceptability score of chapatis of poor‐quality as well as good‐quality wheat flour. High A/X ratio, molecular structure, gelling capacity, water distribution, degree of branching of starches and arabinoxylans, and water availability positively improved the viscosity and rheology of dough, which thus resulted in overall improvement in textural properties of different wheat flours (Courtin and Delcour 2002; Revanappa et al. 2015). These findings indicated that hard wheat possesses a higher level of DMS and arabinoxylans, as compared to extraordinary soft wheat, which greatly influence the texture of chapati. The color of baked chapatis plays a key role in acquiring the quality and sensory scores. The intrinsic peroxidase activity

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of dough affects the color of chapatis. Higher polyphenol oxidases (PPO) and peroxidases (PO) activity leads to the blackening of dough and reduces the consumer acceptability and shelf life of products such as noodle and vermicelli (Hemalatha et al. 2007). Interestingly, higher levels of protein content, gluten strength, and dry gluten content also reduce the overall quality score of chapati. The softness showed a significant positive correlation with hand feel, texture, and overall acceptability of chapatis, while a negative correlation existed with the compression force. Higher protein content and quality of gluten proteins resulted in the formation of chapatis with a firm and elastic texture with lower overall acceptability (Kundu et al. 2017). Extensibility of chapati was increased with higher values of different pasting attributes (e.g., PV and BDV). Higher BDV resulted in a decrease in the moisture content and puffing height of chapatis (Kundu et al. 2017). Therefore, a whole‐wheat flour with higher SDS‐SV, gluten index, PPO levels, and stronger dough characteristics results in firmer, nonpliable and elastic chapatis with lower consumer acceptability. Hard wheat flour possesses a lower proportion of small particle size granules and shows lower NaSRC, WSRC, and SuSRC values (Katyal et  al. 2017). Mixographic properties further indicate the suitability of wheat for different products (Katyal et al. 2017). Mixographic analysis revealed that MPT increases with an increase in UPP content, while higher levels of UPP decrease the MPW of dough of HW, MHW, and Ex‐SW (Katyal et al. 2017). Higher levels of EMP also enhanced the MPV and MPW of dough of HW, MHW, Ex‐SW along with NaSRC, SuSRC, and WSRC. Higher GHI, WA, protein content, NaSRC, SuSRC, and WSRC led to higher RPV (Katyal et al. 2017). These findings confirmed that physical characteristics of grain strongly linked with empirical and fundamental rheology of dough (Katyal et  al. 2017). Therefore, the suitability of wheat for different products should be established by viscoelastic, farinographic, and mixographic properties, along with physicochemical characterizations. Efforts have also been made to enhance the extensibility, softness, and shelf life of chapati using various hydrocolloids. Addition of different levels of potato flour (2–8%) differentially affected the extensibility and tear force of chapatis in a cultivar‐ dependent manner. The mixing of 2% potato flour in wheat flour resulted in the increase in ­extensibility and decrease in energy required to rupture chapatis (Singh et al. 2005). Incorporation of 0.75% guar gum enhanced the softness of chapati many folds (Ghodke and Laxmi 2007). The mixing of lecithin and carboxymethyl cellulose (CMC) in wheat flour resulted in an increase in WA, pasting viscosity, and gluten strength (Khan et al. 2011). β‐carotene, a precursor of vitamin A, and lysine content are highly accumulated in leafy vegetables like spinach and amaranthus, which are abundantly cultivated in India. Therefore, attempts have also been made to enhance the nutraceutical value of chapatis by adding spinach and other leafy products into chapatis. Incorporation of spinach powder, amaranth flour, pulse flour, maize, barley, sorghum, Bengal gram, horse gram, soybean, finger millet, or pearl millet in wheat flour all differentially modulate the textural properties of chapati (Khan et al. 2015; Banerji et al. 2017; Wani et al. 2016; Pande et al. 2017). The differential physicochemical and rheological properties of flour and starches of pulses and pseudocereals may have attributed to poor textural and sensory properties of chapatis made from composite flours.

14.4  Biscuits and Cookies

14.3 ­Gluten‐Free Chapatis The inflammatory disorder known as celiac disease, as well as diabetes and cardiovascular diseases, have increased tremendously in last decades. Patients with celiac disease are advised to avoid consumption of products made from wheat, triticale, rye, barley, durum spelt, kamut, and einkorn for the rest of their life (Taylor 2009). Rice chapatis are not elastic due to lack of polymeric gluten network and show lower extensibility than those made from wheat flour doughs. Hydrocolloids and emulsifiers are widely used to improve the textural properties of different flours. Hydrocolloids possess higher water‐ retention capacity, colloidal nature, and anti‐stalling properties. Incorporation of hydrocolloids such as hydroxypropylmethylcellulose (HPMC) (0.25–0.5%), xanthum (0.25–0.5%), guar gum (0.25–0.5%), and locust bean gum (0.25–0.5%) differentially increase the textural characteristics of rice chapatis. Addition of different hydrocolloids differentially modulate the gelatinization of rice starches (Gujral et al. 2004). Normal corn yields soft chapatis with lower force to rupture and high extensibility, as compared to chapatis of white and waxy corn. The highest force to rupture and the ­lowest extensibility of chapatis of waxy corn is attributed to the presence of lower AC and high protein content. Lack of amylose in waxy corn fails to develop starch‐protein complex during dough formation, thus producing chapatis with low extensibility. The higher extensibility and lower tear force were also observed for chapatis made from the flour of African tall maize (Sandhu et al. 2006). Increased hydration of different corn flour results in an increase in the ratio of intermolecular + antiparallel (AP) β‐sheet, but decreased α‐helix proportion in the dough. Conversely, β‐turns increase differentially and insignificantly among different varieties with the increase in water content. The significant decrease in G′, G″, and tan δ (G″/G′), after hydration, was attributed to the dilution of proteins and lipid, as well as the weakening of starch–protein interactions (Thakur et  al. 2017). Therefore, conformational changes in protein influence the dough rheological and mixing characteristics, as evident from hydration behavior–associated conformational changes in HMW‐GS and gliadins of wheat (Tatham and Shewry 2000).

14.4 ­Biscuits and Cookies Wheat with low‐protein content (8–10%) produces weak dough with low extensibility, WA, DMS, and grain hardness index, and is linked with soft grain texture for biscuit, cookies, and cakes (Kaldy et al. 1993; Pareyt and Delcour 2008). Flour, fat, and sugar are the major ingredients of biscuits and cookies, with low final water content (1–5%) (Chevallier et  al. 2000a, 2002). In terms of percentage, the lesser ingredients include yeast, chemical leavening agents, syrups, salt, and emulsifiers. Cabin biscuits, semi‐ sweet and hard‐sweet biscuits, and sugar‐snap cookies are the major categories of ­cookies (biscuits) in India (Robertson 2011). Minor and major ingredients of cookies are mixed together into a “short” dough, which is basically a mixture of proteins and starch particles surrounded by large fat molecules (Pareyt and Delcour 2008). Unlike chapati dough, which requires extensive mixing to achieve a polymeric gluten network in the dough, cookie/biscuit dough should not be overhandled, so as to avoid the formation of a gluten network. Higher levels of sugars and fat, along with low levels

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of water, do not allow gluten proteins to become hydrated and form a complex gluten networking. Therefore, the cookies dough is sufficiently viscous and cohesive in nature (Hoseney and Rogers 1994). Rolling and sheeting of cookies dough results in weak gluten network formation, which thus reduces the spreading of cookies during baking (Gaines et al. 1988). The cookies flow is a result of an increase in apparent viscosity of dough attributed to the melting of sugars at high temperature, that is not because of gelatinization of starches. Sugars also help in creaming air into the fat and maintain moisture during the baking of cakes, cookies, and biscuits. The sugars act as anti‐plasticizer and emulsifier of dough, raise the gelatinization temperature, and decrease the degree of gelatinization of starches in cookies dough, which improve the crispiness of cookies and contribute to proper browning (Chan 2014). The polymeric gluten network formation in cookies dough significantly affects dough consistency, cookie hardness, texture, and sensory parameters (Chevallier et al. 2000a, b) (Figure 14.2). Barak et al. (2013) demonstrated that cookie spread and hardness are influenced by GHI, DMS and protein content in flour. The hardness of cookies increased with an increase in DMS content in the flour (Barak et al. 2013; Barak et al. 2014a). The WA of DMS is much higher than that of native starches; therefore, higher DMS content in flour leads to an increase in WA of dough (Farrand 1972). Cookies are low‐moisture baked products; therefore, higher levels of water bring stiffness in the cookies dough, which results in a decrease in diameter and spread ratio and an increase in the hardness

HLW GC SDS-SV Glu1-S Glut DS WA FN HPV CPV

Positive (+) Correlation (–)Negative

206

Gli:Glu

DS

Spread Factor

Hardness

DS PC AWRC SDS-SV NaSRC WSRC LaSRC

Total Score

GH AC Glut DS FN

Appearance & Color

Glia Gli:Glut

Glia

GS TS

Aroma Taste Flavor

HLW GC PC SDS-SV Glu1-S DS WA

AC Glia

HLW Glut DS WA

Puffed Hight

Shear Value

Tearing Strength

HLW Glut DS

PV HPV CPV

QUALITY PARAMETERS OF COOKIES & BISCUITS

Figure 14.2  An illustration describing relationship among different textural characteristics of cookies and biscuits. AWRC: alkaline water retention capacity; SDS‐SV; sodium dodecyl sulfate‐sedimentation value; HLW: hectoliter weight; Glut: glutenin; DS: dough stability; NaSRC: sodium carbonate solvent retention capacity (SRC); WSRC: water SRC; LaSRC: lactic acid SRC; Gli:Glut: gliadin to glutenin ratio; WA: water absorption capacity; PV: pasting viscosity; HPV: hot paste viscosity; CPV: cold paste viscosity; AC: amylose content; Glia: gliadin; Glu1‐S: Glu‐1 score; TS; tearing strength; GH: grain hardness; FN: falling number; GC: glutenin content.

14.5  Gluten‐Free Cookies and Biscuits

of cookies (Barak et al. 2013). The ratio of monomeric and polymeric proteins positively affects cookie spread and negatively influences hardness. Incorporation of purified gliadins in the dough results in an increase in the spread and softness of cookies (Kuragano et al. 1991; Barak et al. 2013). The treatment of cookies dough with purified γ‐gliadin fractions results in an increase in the extensibility of dough, thereby improving their quality (Uthayakumaran et al. 2001). The ratio of monomeric and polymeric proteins is an important parameter for the production of good‐quality cookies (Barak et al. 2013). Therefore, soft wheat is preferred for cookies and biscuits manufacturing due to low DMS and weak gluten strength. Studies show that an increase in NSPs in cookies dough results in a decrease in cookies diameter, poorer top grain and cell characteristics, as well as an increase in softness and moistness (Kaldy et al. 1993; Ram and Singh 2004) (Figure 14.2). Wheat flour contains very low level of polar and nonpolar lipids (15 μm), followed by medium (B : 5–15 μm) starch granules, while the proportion of small (C: