Wheat: Environment, Food and Health

424 Pages·2022·11.017 MB·English

by  Mike J. Gooding, Peter R. Shewry

Wheat
Wheat
Environment, Food and Health
Mike J. Gooding
Aberystwyth University,
Aberystwyth, UK
Peter R. Shewry
Rothamsted Research,
Harpenden, UK
&
University of Reading,
Reading, UK
This edition first published 2022
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Library of Congress Cataloging- in- Publication Data
Names: Gooding, Mike J., author. | Shewry, Peter R., author.
Title: Wheat : environment, food and health / Mike J. Gooding, Aberystwyth
University, Aberystwyth, UK, Peter R. Shewry, Rothamsted Research,
Harpenden, UK & University of Reading, Reading, UK.
Description: Hoboken, NJ : Wiley, 2022. | Includes bibliographical
references and index.
Identifiers: LCCN 2021046095 (print) | LCCN 2021046096 (ebook) | ISBN
9781119652557 (hardback) | ISBN 9781119652588 (adobe pdf) | ISBN
9781119652595 (epub)
Subjects: LCSH: Wheat. | Wheat–History. | Wheat trade–History.
Classification: LCC SB191.W5 G665 2021 (print) | LCC SB191.W5 (ebook) |
DDC 633.1/1–dc23
LC record available at https://lccn.loc.gov/2021046095
LC ebook record available at https://lccn.loc.gov/2021046096
Cover Design: Wiley
Cover Images: Courtesy of Richard Casebow, Crops Research Unit, University of Reading, UK;
Courtesy of Mike Gooding; Courtesy of Rothamsted Research Ltd
Set in 9.5/12.5pt STIXTwoText by Straive, Pondicherry, India
10 9 8 7 6 5 4 3 2 1
We would like to dedicate this volume to our friends and colleagues Prof. W. Paul Davies
(1949–2016) and Dr. Donald D. Kasarda (1933–2021).
vii
Contents
Foreword xv
Acknowledgements xvi
1 Wheat and Humans: An Introduction to the Development and Utilisation of the
Wheat Crop 1
1.1 Wheat Production in the Past and Present 1
1.1.1 Co- Evolution of Wheat Production and Human Societies 1
1.1.2 Wheat Supply and Demand 4
1.1.3 Wheat Adaptation 7
1.2 The Wheat Plant 9
1.2.1 Vegetative Phase 14
1.2.1.1 Germination 14
1.2.1.2 Leaves 15
1.2.1.3 Tillers 16
1.2.1.4 Roots 16
1.2.2 Reproductive Phase 16
1.2.2.1 Stem Extension 17
1.2.2.2 Booting and Ear Emergence 18
1.2.2.3 Anthesis 18
1.2.2.4 Grain Growth 19
1.3 Wheat Evolution and Migration 20
1.3.1 Origin in the Fertile Crescent 20
1.3.2 Wild Wheats 21
1.3.3 Domestication 22
1.3.4 The Spread of Wheat Cultivation 23
1.3.5 Increases in Harvest Index 24
1.4 Wheat as Food 25
1.4.1 The Development of Milling and Baking 25
1.4.2 The Cultural Significance of Bread 28
1.4.3 Bread Today 30
1.4.4 The Fall and Rise of Whole Grain Foods 31
1.4.5 Producing White and Wholemeal Flours by Roller Milling 33
viii Contents
1.5 Grain Quality 33
1.5.1 Grain Size, Shape, and Specific Weight 33
1.5.2 Endosperm Texture 35
1.5.3 Water Absorption 35
1.5.4 Gluten 36
1.5.4.1 The Origin and Properties of Gluten 36
1.5.4.2 Gluten and Health 37
1.5.4.3 Dough Properties that Determine Processing Quality 37
1.5.4.4 Importance of Total Protein Concentration 38
1.5.4.5 Importance of Protein Quality 40
1.5.4.6 Measurement of Dough Rheology and Quality 40
1.5.5 Other Factors Affecting the Acceptability of Wheat for Different End-U ses 41
1.5.5.1 Alpha- Amylase Activity 41
1.5.5.2 Seed Coat Colour 42
1.6 Further Chapters 42
References 42
2 A ‘Good’ Soil 52
2.1 Soils for Wheat Production 53
2.1.1 Soil Taxonomy 53
2.1.2 Soil Texture 54
2.1.3 Soil Organic Matter 56
2.1.4 Soil pH and Sodicity 58
2.1.5 Salinity 60
2.1.6 Soil Structure 61
2.1.7 Soil Depth 63
2.1.8 Land Classification 63
2.2 The Rise of the Plough 64
2.3 Soil Change and Land Degradation 66
2.3.1 Loss of Soil 66
2.3.2 Organic Matter Loss and Amendment 70
2.3.3 Acidification and Liming 74
2.3.3.1 Calcium as a Nutrient 75
2.3.4 Depletion of Micronutrients 76
2.3.4.1 Boron 76
2.3.4.2 Chlorine 76
2.3.4.3 Copper 77
2.3.4.4 Iron 77
2.3.4.5 Manganese 78
2.3.4.6 Molybdenum 78
2.3.4.7 Nickel 78
2.3.4.8 Zinc 79
2.3.5 Salinisation 79
2.3.6 The Weed Seedbank 80
2.4 Systems for Protecting the Soil 82
Contents ix
2.4.1 Conservation Tillage 82
2.4.2 Organic Farming 84
2.4.3 Conservation Agriculture 85
2.5 Land- Use Efficiency and Soils 86
References 87
3 Ample Water 101
3.1 The Water Requirement of Wheat 103
3.1.1 Germination and Seedling Emergence 103
3.1.2 Transpiration 104
3.1.3 Root Growth 108
3.1.4 Reproductive Growth and Grain Filling 109
3.2 Available Water 113
3.2.1 Soil Water 113
3.2.2 Rainfall 114
3.2.2.1 Rainfall Shortage 115
3.2.2.2 Rainfall Excess 116
3.2.3 Irrigation 117
3.2.3.1 Surface Irrigation 119
3.2.3.2 Overhead Irrigation 119
3.2.3.3 Sources of Irrigation Water 120
3.3 Water Use Efficiency 122
3.3.1 Reducing Evaporation Losses 122
3.3.2 Increasing Rooting at Depth 122
3.3.3 Deficit Irrigation 124
3.3.4 Osmotic Adjustment 124
3.3.5 Transpiration Efficiency 125
3.3.6 Potassium 125
3.4 Land- Use Efficiency and Water 127
References 128
4 Mild Temperatures 139
4.1 The Temperature Requirement for Wheat 140
4.2 ‘Waiting for Fine Times’ (Snape et al. 2001) 142
4.2.1 Dormancy 142
4.2.2 Cold Acclimation 143
4.2.3 Vernalisation 144
4.2.4 Photoperiodism 145
4.2.5 Earliness per se 147
4.3 Vegetative Growth and Development 147
4.3.1 Germination and Emergence 147
4.3.2 Leaves 148
4.3.3 Tillers 150
4.3.4 Roots 150
4.4 Reproductive Growth and Development 151
x Contents
4.4.1 Spikelet Formation and Stem Extension 151
4.4.2 Meiosis and Anthesis 151
4.4.2.1 Heat Stress 151
4.4.2.2 Cold Stress 154
4.4.3 Grain Filling and Quality 154
4.5 Global Warming 156
References 157
5 Sunshine 166
5.1 The Light Requirement of Wheat 170
5.1.1 Light Quantity 170
5.1.2 Light Quality 175
5.2 Light Interception 176
5.3 Improving Radiation Use for Increased Land- Use Efficiency 179
References 181
6 Canopy Management 186
6.1 Crop Establishment 186
6.1.1 Sowing Date 186
6.1.2 Plant Populations and Sowing Rate 188
6.2 Crop Nutrition 193
6.2.1 Nitrogen 194
6.2.1.1 The Requirement for Nitrogen 194
6.2.1.2 Nitrogen Fixation 201
6.2.1.3 Nitrogen Efficiencies and Losses 205
6.2.1.4 Recovering and Recycling Fixed Nitrogen 211
6.2.1.5 Optimising Nitrogen Application 214
6.2.2 Phosphorus 218
6.2.3 Sulphur 221
6.2.4 Magnesium 224
6.3 Diseases and their Control 224
6.3.1 The Rusts 226
6.3.1.1 Yellow Rust 226
6.3.1.2 Leaf Rust 227
6.3.1.3 Stem Rust 227
6.3.2 The Blotch Diseases 228
6.3.2.1 Septoria tritici Blotch 228
6.3.2.2 Septoria nodorum Blotch 229
6.3.2.3 Tan Spot 230
6.3.3 Diseases Contributing to Mycotoxins in the Grain 230
6.3.3.1 Ergot 230
6.3.3.2 Fusarium Head Blight (FHB) 231
6.3.4 Fungicides and Fungicide Use 232
6.4 Land- use Efficiency and Canopy Management 238
References 240
Contents xi
7 The Structure and Composition of the Wheat Grain 263
7.1 Grain Development 263
7.1.1 Fertilisation 263
7.1.2 Post- fertilisation 265
7.1.3 Endosperm Development 265
7.1.4 Embryo Development 267
7.2 Structure of the Mature Grain 268
7.3 Major Components of the Mature Grain 271
7.3.1 Carbohydrates 272
7.3.1.1 Monosaccharides, Disaccharides, and Oligosaccharides 272
7.3.1.2 Starch 272
7.3.1.3 Cell Wall Polysaccharides 274
7.3.1.4 Arabinogalactan Peptide (AGP) 276
7.3.2 Proteins 277
7.3.2.1 Grain Protein Content (GPC) 277
7.3.2.2 Grain Protein Deviation 277
7.3.2.3 Essential Amino Acid Composition 278
7.3.2.4 Wheat Grain Proteins 279
7.3.2.5 Gluten Proteins: Gliadins and Glutenins 280
7.3.2.6 Other Proteins of the Prolamin Superfamily 287
7.3.2.7 Other Storage Proteins 291
7.3.2.8 Other Inhibitors and Putative Defensive Proteins 292
7.3.2.9 Xylanases and Xylanase Inhibitors 293
7.3.3 Lipids 293
7.3.4 Minor Components: Minerals, Vitamins, and Phytochemicals 294
7.4 Gradients in Composition within the Starchy Endosperm 295
References 296
8 Components and Mechanisms that Determine Grain Processing Properties 301
8.1 Grain Hardness and Vitreousness 301
8.1.1 Friabilin and Puroindolines 302
8.1.2 Other Proteins that Affect Grain Hardness 303
8.1.3 Role of Lipids 304
8.1.4 When and How is Grain Softness Established? 304
8.1.5 Vitreousness 305
8.2 Dough Viscoelasticity 305
8.2.1 Wheat Gluten and Dough Viscoelasticity 305
8.2.2 HMW Subunits, Dough Strength, and Breadmaking Quality 307
8.2.3 Effects of Other Gluten Proteins on Dough Quality 308
8.2.4 Molecular Basis for the Role of the HMW Subunits in Gluten Structure
and Properties 308
8.3 Functional Properties of Starch 309
8.3.1 Starch Gelatinisation 310
8.3.2 Starch Damage 310
8.3.3 Starch Retrogradation and Staling 311
xii Contents
8.3.4 Waxy and High Amylose Starches 311
8.4 Other Functional Components 311
8.4.1 Arabinoxylan 311
8.4.2 Functional Properties of Lipids in Dough 312
8.4.3 Water Absorption: Effects of Starch, Protein, and Fibre 312
8.5 Effects of Crop Nutrition and Environmental Factors on Grain Composition
and Quality 313
8.5.1 Nitrogen Fertilisation 313
8.5.2 Sulphur Availability 314
8.5.2.1 Sulphur Nutrition, Asparagine Content, and Acrylamide Formation 315
8.5.3 Temperature and Water Availability 316
8.5.4 Carbon Dioxide Concentration 317
References 318
9 The Role of Wheat in Diet and Health 321
9.1 Contribution of Wheat to the Human Diet 321
9.2 Dietary Fibre 321
9.2.1 Proposed and Approved Benefits of Dietary Fibre 321
9.2.2 Wheat Grain Fibre 324
9.2.2.1 Cell Wall Polysaccharides 324
9.2.2.2 Fructans 325
9.2.2.3 Resistant Starch 325
9.2.2.4 High Amylose Starch 325
9.2.3 Mechanism of Action of Dietary Fibre 326
9.2.3.1 Role of Food Structure and Breakdown 326
9.2.3.2 Role of Luminal Viscosity 327
9.2.3.3 Role of Prebiotic Activity 327
9.3 Micronutrients and Phytochemicals 327
9.3.1 Iron and Zinc 327
9.3.2 Selenium 330
9.3.3 B Vitamins 330
9.3.4 Phytochemicals 331
9.3.4.1 Phenolics 331
9.3.4.2 Terpenoids 333
9.3.5 Betaine and Choline 333
9.3.6 Health Benefits of Phytochemicals 335
9.3.7 Environmental Effects on the Concentrations of Phytochemicals
and Minerals 337
9.4 Adverse Effects of Wheat on Health 338
9.4.1 Wheat as Part of the Western Diet 338
9.4.2 Allergy and Intolerance to Wheat 338
9.4.3 Allergy 338
9.4.4 Coeliac Disease and Related Intolerances 340
9.4.5 Other Adverse Reactions to Wheat 341
9.4.6 FODMAPs and Gastro- Intestinal Disorders 341