Wheat Antioxidants

This comprehensive reference consolidates current information on the antioxidant properties of wheat, their beneficial effects, the mechanisms involved, factors affecting availability/bioavailability, and the methods used to measure them. It discusses antioxidant properties of wheat grains and fractions and their phytochemical compositions and covers the effects of genotype, growing conditions, post-harvest treatment, storage, and food formulation and processing on availability/bioavailability. Wheat Antioxidants will help cereal chemists, food technologists, food processors, nutritionists, and others maximize the health benefits of wheat-based foods.

Table of Contents:
Contributors xi CHAPTER 1 OVERVIEW AND PROSPECTIVE 1 1.1 Introduction 1 1.2 Antioxidant Properties of Wheat Grain 2 1.3 Other Biological Activities of Wheat Antioxidants 3 1.4 Wheat Antioxidants: Opportunities and Challenges 5 CHAPTER 2 ANTIOXIDANT PROPERTIES OF WHEAT GRAIN AND ITS FRACTIONS 7 2.1 Sample Preparation 8 2.2 Total Phenolic Content (TPC) and Total Antioxidant Capacity (TAC) of Wheat Fractions 8 2.3 Iron(II)-Chelating Activity of Wheat Fractions 11 2.4 Oxygen Radical Absorbance Capacity (ORAC) of Wheat Fractions 13 2.5 Inhibition of Photochemiluminescence (PCL) by Wheat Fractions 14 2.6 Effect of Milling and Pearling of Wheat on Inhibition of Low-Density Lipoprotein (LDL) Oxidation 17 2.7 Influence of Milling and Pearling on Homediated Supercoiled DNA Scission by Wheat 19 2.8 Conclusions 20 CHAPTER 3 EFFECTS OF GENOTYPE, ENVIRONMENT AND GENOTYPE • ENVIRONMENT INTERACTION ON THE ANTIOXIDANT PROPERTIES OF WHEAT 24 3.1 Introduction 24 3.2 Genotype Effects 26 3.2.1 Total Phenolic Content 27 3.2.2 Phenolic Acid Composition 28 3.2.3 DPPH Scavenging Capacity 31 3.2.4 Superoxide Scavenging Capacities 31 3.2.5 Peroxyl Radical Scavenging Capacities 32 3.3 Environment Effects 32 3.4 Genotype by Environment Interaction Effects 33 3.5 Relative Contribution of G, E, and G • E Effects to Total Variation 35 3.6 Concluding Remarks 37 CHAPTER 4 CAROTENOID, TOCOPHEROL, LIGNAN, FLAVONOID, AND PHYTOSTEROL COMPOSITIONS OF WHEAT GRAIN AND ITS FRACTIONS 42 4.1 Introduction 42 4.2 Phytochemical Composition of Wheat 43 4.2.1 Polyphenols (Lignans, Flavonoids) 43 4.2.2 Carotenoids 46 4.2.3 Tocopherols and Tocotrienols 48 4.2.4 Phytosterols and Phytostanols 49 4.2.5 Antioxidant Activities and Health Benefits 49 4.3 Conclusion 52 CHAPTER 5 ANTIOXIDANT PROPERTIES OF WHEAT PHENOLIC ACIDS 54 5.1 Introduction 54 5.2 Phenolic Acid Contents in Wheat Grain and Fractions 54 5.3 Free Radical Scavenging Capacity of Wheat Phenolic Acids 59 5.4 Inhibitory Effect of Wheat Phenolic Acids on Lipid Peroxidation 64 5.5 Chelating Properties of Wheat Phenolic Acids 66 5.6 Other Antioxidant Activities of Wheat Phenolic Acids 66 5.7 Structure–Activity Relationship of Wheat Phenolic Acids 70 CHAPTER 6 EFFECTS OF POSTHARVEST TREATMENTS, FOOD FORMULATION, AND PROCESSING CONDITIONS ON WHEAT ANTIOXIDANT PROPERTIES 73 6.1 Introduction 73 6.2 Wheat Postharvest Treatments 74 6.2.1 Wheat Flour Milling 74 6.2.2 Pearling or Debranning 76 6.2.3 Storage of Wheat and Wheat Products 77 6.2.4 Other Postharvest Treatments 78 6.3 Food Formulations 79 6.4 Food Heat Processing 82 6.5 Summary 86 CHAPTER 7 ANTIOXIDANT PROPERTIES OF WHEAT-BASED BREAKFAST FOODS 88 7.1 Introduction 88 7.2 Whole Grains for Health & Wellness 88 7.3 Grains Classification and Consumption 89 7.4 Wheat Types, Morphology, and Composition 90 7.5 Role of Antioxidants in Wheat and Other Cereal Grains 90 7.6 Wheat Milling and Distribution of Antioxidants 91 7.7 Wheat-Based Breakfast Foods 92 7.8 Breakfast Meal Consumption and Demographics 92 7.9 Antioxidants in RTE Breakfast Cereals 93 7.10 Antioxidants and Bread Making 95 7.11 Conclusion 96 CHAPTER 8 EFFECTS OF EXTRACTION METHOD AND CONDITIONS ON WHEAT ANTIOXIDANT ACTIVITY ESTIMATION 100 8.1 Introduction 100 8.2 Extraction Methods and Conditions 101 8.2.1 Effects of Extraction Method 105 8.2.2 Effects of Extraction Conditions 106 8.3 General Considerations for Sample Preparation and Extraction 113 8.4 Extraction Condition Recommendations for Wheat Antioxidant Property Estimation 114 CHAPTER 9 METHODS FOR ANTIOXIDANT CAPACITY ESTIMATION OF WHEAT AND WHEAT-BASED FOOD PRODUCTS 118 9.1 Introduction 118 9.2 DPPH Radical Scavenging Capacity Assay 120 9.2.1 Principles and Background 120 9.2.2 Materials and Solutions Preparation 121 9.2.3 Discussion 124 9.3 ABTS Cation Radical (ABTS_+) Scavenging Capacity Assay 125 9.3.1 Principles and Background 125 9.3.2 Materials and Solutions Preparation 126 9.3.3 Measuring Procedure 127 9.3.4 Calculations 127 9.3.5 Discussion 128 9.4 Superoxide Anion Radical (O2__) Scavenging Capacity Assay 130 9.4.1 Principles and Background 130 9.4.2 Materials and Solutions Preparation 131 9.4.3 Procedure 131 9.4.4 Calculations 131 9.4.5 Discussion 132 9.5 Oxygen Radical Absorbing Capacity (ORAC) Assay 133 9.5.1 Principles and Background 133 9.5.2 Materials and Solutions Preparation 134 9.5.3 Calculations 135 9.5.4 Discussion 136 9.6 Hydroxyl Radical (_OH) Scavenging Capacity (HOSC) Assay for Hydrophilic Antioxidants 138 9.6.1 Principles and Background 138 9.6.2 Materials and Solutions Preparation 139 9.6.3 Calculations 140 9.6.4 Discussion 141 9.6.5 Other Reported Methods for Hydroxyl Radical Scavenging Capacity Estimation 142 9.7 Hydroxyl Radical Scavenging Capacity Assay for Lipophilic Antioxidants Using ESR 143 9.7.1 Principles and Background 143 9.7.2 Materials and Solutions Preparation 144 9.7.3 Procedure 144 9.7.4 ESR Parameters 144 9.7.5 Calculations 145 9.7.6 Discussion 146 9.8 Total Phenolic Contents Assay Using the Folin–Ciocalteu Reagent 147 9.8.1 Principles and Background 147 9.8.2 Procedure 148 9.8.3 Calculations 149 9.8.4 Discussion 149 9.9 Iron(II) Chelating Capacity Assay 150 9.9.1 Principles and Background 150 9.9.2 Procedure 153 9.9.3 Calculations 154 9.9.4 Discussion 154 9.10 Copper(II) Chelating Capacity Assay 155 9.10.1 Principles and Background 155 9.10.2 Materials and Solutions Preparation 156 9.10.3 Procedure 156 9.10.4 ESR Parameters 156 9.10.5 Discussion 158 9.11 Lipid Peroxidation Inhibition Assay (OSI) 158 9.11.1 Principles and Background 158 9.11.2 Results 160 9.11.3 Discussion 160 9.12 Low-Density Lipoprotein (LDL) Peroxidation Inhibition Assay 162 9.12.1 Principles and Background 162 9.12.2 Discussion 165 9.13 Conclusions 166 CHAPTER 10 APPLICATION OF ESR IN WHEAT ANTIOXIDANT DETERMINATION 173 10.1 Introduction 173 10.2 The Principles of ESR 174 10.3 The Application of ESR in Food Systems 176 10.4 ESR Determination of Wheat Antioxidants 179 10.4.1 Free Radical Scavenging Capacities of Wheat Antioxidants 179 10.4.2 Chelating Activity Against Cu2+ 184 10.4.3 Effects of Wheat Antioxidants on Lipid Peroxidation in Liposomes 185 CHAPTER 11 ANALYSIS OF TOCOPHEROLS AND CAROTENOIDS IN WHEAT MATERIALS USING LIQUID CHROMATOGRAPHY–MASS SPECTROMETRY TECHNOLOGY 190 11.1 Introduction 190 11.2 Terminology 193 11.3 Analysis of Tocopherols and Carotenoids by LC-MS Technology 193 11.3.1 Liquid–Liquid Extraction 194 11.3.2 Chromatographic Separation 197 11.3.3 LC–MS Interfaces and MS Detection 201 11.4 Summary 204 CHAPTER 12 QUANTIFICATION OF PHENOLIC ACIDS IN WHEAT AND WHEAT-BASED PRODUCTS 208 12.1 Introduction 208 12.2 Background 209 12.3 Chemicals and Equipments 209 12.4 Methods 210 12.4.1 Sample Preparation 1 210 12.4.2 Sample Preparation 2 According to the Protocol Reported by Kim et al. (Fig. 12.2) 211 12.4.3 HPLC Separation and Determination 213 12.5 Discussion 213 CHAPTER 13 EFFECTS OF WHEAT ON NORMAL INTESTINE 219 13.1 Introduction 219 13.2 Wheat Component Effects on Normal Intestinal Epithelial Cells in vitro 220 13.2.1 Background Information 220 13.2.2 Effects of Wheat Bran Extract on IEC-6 Cell Proliferation 222 13.2.3 Ferulic Acid and IEC-6 Cell Proliferation 224 13.3 Discussion 232 13.4 Conclusion 234 CHAPTER 14 WHEAT ANTIOXIDANTS AND CHOLESTEROL METABOLISM 236 14.1 Introduction 336 14.2 Wheat Antioxidants 236 14.2.1 Phenolic Acids 237 14.2.2 Carotenoids 237 14.2.3 Tocopherols 237 14.3 Wheat Antioxidant Properties 238 14.4 Cholesterol Homeostasis 239 14.5 Effects of Wheat Antioxidants on Cholesterol Metabolism 240 14.6 Summary 241 CHAPTER 15 WHEAT ANTIOXIDANT BIOAVAILABILITY 244 15.1 Introduction 244 15.2 Absorption Characteristics of Fluorescein In Vitro 245 15.3 Absorption Characteristics of Phenolic Acid In Vitro 247 15.3.1 FA and PCA 247 15.3.2 CA, CLA, GA, and RA 248 15.3.3 Artepillin C (AC) 249 15.4 Absorption Efficiency and Bioavailability of Phenolic Acid in Rats 251 15.5 Absorption Characteristics of Colonic Metabolites of Poorly Absorbed Polyphenols In Vitro 253 15.6 Current Knowledge and Status of the MCT-Mediated Transport System 256 15.6.1 Gastric Absorption 256 15.6.2 MCT Subtype Responsible for Transport of PAs and Microbial Metabolites of Polyphenols 256 15.6.3 Concept of Metabonutrients 257 15.7 Overview of Absorption and Bioavailability of Wheat Antioxidants: Future Studies 258 15.7.1 SRA, SPA, VA and PBA 258 15.7.2 Free, Soluble Conjugate, and Insoluble Bound PAs in Wheat 259 CHAPTER 16 WHEAT LIGNANS: PROMISING CANCER PREVENTIVE AGENTS 264 16.1 Introduction 264 16.2 Lignans and Cancer Prevention 266 16.2.1 Epidemiological and Clinical Studies 267 16.2.2 Experimental Animal Studies 267 16.3 Plausible Mechanisms of Lignans for Cancer Prevention 268 INDEX

About the Author :
Liangli Yu, PhD, is an Associate Professor in the Department of Nutrition and Food Science at the University of Maryland in College Park, where she specializes in the chemistry andbiochemistry of nutraceuticals and foods. Dr. Yu received her PhD in food science from Purdue University in 1999.

Review :
"The book presents current information on antioxidant compounds of wheat." (Food Science and Technology Abstracts, September 2008)