A manual designed for Food Chemistry Laboratory courses that meet Institute of Food Technologists undergraduate education standards for degrees in Food Science
In the newly revised second edition of Food Chemistry: A Laboratory Manual, two professors with a combined 50 years of experience teaching food chemistry and dairy chemistry laboratory courses deliver an in-depth exploration of the fundamental chemical principles that govern the relationships between the composition of foods and food ingredients and their functional, nutritional, and sensory properties. Readers will discover practical laboratory exercises, methods, and techniques that are commonly employed in food chemistry research and food product development.
Every chapter offers introductory summaries of key methodological concepts and interpretations of the results obtained from food experiments. The book provides a supplementary online Instructor’s Guide useful for adopting professors that includes a Solutions Manual and Preparation Manual for laboratory sessions.
The latest edition presents additional experiments, updated background material and references, expanded end-of-chapter problem sets, expanded use of chemical structures, and: - A thorough emphasis on practical food chemistry problems encountered in food processing, storage, transportation, and preparation - Comprehensive explorations of complex interactions between food components beyond simply measuring concentrations - Additional experiments, references, and chemical structures - Numerous laboratory exercises sufficient for a one-semester course
Perfect for students of food science and technology, Food Chemistry: A Laboratory Manual will also earn a place in the libraries of food chemists, food product developers, analytical chemists, lab technicians, food safety and processing professionals, and food engineers.
Table of Contents
Preface to the Second Edition xv
Preface to the First Edition xvi
Acknowledgments xvii
About the Companion Website xix
1 Acids, Bases, and Buffers 1
1.1 Learning Outcomes 1
1.2 Introduction 1
1.2.1 Acids 1
1.2.1.1 Food Acidulants 2
1.2.1.2 Reactions of Food Acids 3
1.2.2 Bases 3
1.2.3 Buffers 3
1.3 Apparatus and Instruments 3
1.4 Reagents and Materials 4
1.5 Procedures 5
1.5.1 Determining the pH of a Solid Food 5
1.5.2 Preparation of a Buffer and Determination of Buffer Capacity 5
1.6 Problem Set 5
1.7 References 6
1.8 Suggested Reading 6
Answers to Problem Set 6
2 Chemical Leavening Agents 7
2.1 Learning Outcomes 7
2.2 Introduction 7
2.2.1 Chemical Leavening Agents 8
2.2.1.1 Baking Soda 8
2.2.1.2 Baking Powders 8
2.2.2 Neutralizing Values 10
2.2.3 Leavening Rates 11
2.2.4 Effect of Leavening Acid on Dough Rheology 11
2.3 Apparatus and Instruments 11
2.4 Reagents and Materials 12
2.5 Procedures 12
2.5.1 Determination of Leavening Rates 12
2.5.1.1 The Apparatus 12
2.5.1.2 Experimental Treatments and Controls 12
2.5.1.3 Protocol 13
2.5.1.4 Data Analysis 13
2.5.2 Chemically Leavened Biscuits 13
2.5.2.1 Biscuit Formula 13
2.5.2.2 Treatments 14
2.5.2.3 Protocol 14
2.5.2.4 Volume Determination of Biscuits 14
2.6 Problem Set 14
2.7 Useful Formulas and Values 15
2.8 References 16
2.9 Suggested Reading 16
Answers to Problem Set 16
3 Properties of Sugars 19
3.1 Learning Outcomes 19
3.2 Introduction 19
3.3 Apparatus and Instruments 20
3.4 Reagents and Materials 21
3.5 Procedures 21
3.6 Study Questions 22
3.7 References 22
3.8 Suggested Reading 22
4 Nonenzymatic Browning 23
4.1 Learning Outcomes 23
4.2 Introduction 23
4.2.1 Caramelization 23
4.2.2 The Maillard Reaction 24
4.2.2.1 Sugar 25
4.2.2.2 Amine 25
4.2.2.3 Temperature 26
4.2.2.4 Concentration 27
4.2.2.5 pH 27
4.3 Apparatus and Instruments 27
4.4 Reagents and Materials 28
4.4.1 Reagents to Be Prepared by the Student 28
4.4.2 Reagents to Be Prepared by the Teaching Staff 28
4.5 Procedures 28
4.5.1 Preparation of a Glucose/Glycine Model System 28
4.5.2 Heating Experiment 29
4.5.3 Measurement of Extent of Browning 29
4.5.4 Browning in Nonfat Dry Milk (Demonstration) 29
4.5.5 Role of Milk in Crust Color of Bread (Demonstration) 29
4.5.6 Browning in Cookies 30
4.5.6.1 Sugar Cookie Formula 30
4.5.6.2 Baking Directions 30
4.6 Problem Set 31
4.7 Study Questions 31
4.8 References 31
4.9 Suggested Reading 32
Answers to Problem Set 32
5 Food Hydrocolloids 33
5.1 Learning Outcomes 33
5.2 Introduction 33
5.2.1 Alginate 34
5.2.2 Alginate Gels 35
5.2.3 Carrageenan 36
5.2.4 Locust Bean Gum and Guar Gum 37
5.2.5 Xanthan Gum 39
5.3 Apparatus and Instruments 39
5.4 Reagents and Materials 39
5.5 Procedures 40
5.5.1 Effect of Heat Treatment on Gelation 40
5.5.2 Effect of Concentration on Viscosity 40
5.5.3 Emulsion Stability 40
5.5.4 Diffusion Setting and Internal Setting Alginate Gels 41
5.5.4.1 Diffusion Setting Gel 41
5.5.4.2 Internal Setting Gel 41
5.6 Study Questions 41
5.7 References 41
5.8 Suggested Reading 42
6 Functional Properties of Proteins 43
6.1 Learning Outcomes 43
6.2 Introduction 43
6.2.1 Soybean Processing: Soy Milk, Tofu, and Soybean Protein Isolate 44
6.2.2 Assaying Protein Concentration 45
6.3 Apparatus and Instruments 45
6.4 Reagents and Materials 46
6.5 Procedures 46
6.5.1 Standard Curve for the Bradford Protein Assay 46
6.5.2 Effect of pH on Protein Solubility 46
6.5.2.1 Preparation of Protein Extracts 46
6.5.2.2 Measurement of Protein Concentration in the Extracts 47
6.5.3 Preparation of Soy Protein Isolate and Tofu 47
6.5.3.1 Extraction 47
6.5.3.2 Soy Protein Isolation 47
6.5.3.3 Production of Tofu 47
6.6 Problem Set 48
6.7 Study Questions 48
6.8 References 48
6.9 Suggested Reading 49
Answers to Problem Set 49
7 Lactose 51
7.1 Learning Outcomes 51
7.2 Introduction 51
7.2.1 Lactose Assay 53
7.3 Apparatus and Instruments 54
7.4 Reagents and Materials 55
7.5 Procedures 55
7.5.1 Lactose and D-galactose Assay Protocol 55
7.5.2 Lactase Assay 55
7.6 Experimental Design 55
7.7 Study Questions 56
7.8 References 56
7.9 Suggested Reading 56
8 Enzymatic Browning: Kinetics of Polyphenoloxidase 57
8.1 Learning Outcomes 57
8.2 Introduction 57
8.2.1 Enzyme Kinetics 57
8.2.2 PPO Assay 61
8.2.3 Control of Enzymatic Browning 62
8.3 Apparatus and Instruments 62
8.4 Reagents and Materials 63
8.5 Procedures 63
8.5.1 Preparation of Crude Enzyme Extract 63
8.5.2 Enzyme Assay 63
8.5.3 Data Treatment 64
8.5.4 Required Notebook Entries 64
8.6 Problem Set 64
8.7 Study Questions 65
8.8 References 66
Answers to Problem Set 66
9 Blanching Effectiveness 67
9.1 Learning Outcomes 67
9.2 Introduction 67
9.3 Apparatus and Instruments 69
9.4 Reagents and Materials 69
9.5 Procedures 70
9.6 Study Questions 70
9.7 References 70
9.8 Suggested Reading 70
10 Lipid Oxidation 71
10.1 Learning Outcomes 71
10.2 Introduction 71
10.2.1 The Chemistry of Lipid Oxidation 71
10.2.2 Control of Lipid Oxidation 75
10.2.2.1 Elimination of Oxygen 75
10.2.2.2 Scavenging of Free Radicals 75
10.2.2.3 Chelation of Metal Ions 76
10.2.3 Measurement of Lipid Oxidation in Foods 76
10.2.3.1 Thiobarbituric Acid Test (TBA Test) 76
10.2.3.2 Peroxide Value 77
10.2.3.3 Conjugated Diene Methods 77
10.2.3.4 Oxygen Bomb Test 77
10.2.3.5 Total and Volatile Carbonyl Compounds 77
10.2.3.6 Anisidine Value Test 77
10.3 Apparatus and Instruments 78
10.4 Reagents and Materials 78
10.5 Procedures: Lipid Oxidation in Turkey Meat 78
10.6 Problem Set: Calculation of TBARS 79
10.7 Study Questions 80
10.8 References 81
10.9 Suggested Reading 81
Answers to Problem Set 82
11 Ascorbic Acid: Stability and Leachability 83
11.1 Learning Outcomes 83
11.2 Introduction 83
11.2.1 Chemistry 83
11.2.2 Functions of Ascorbic Acid in Foods 85
11.2.2.1 Oxygen Scavenger 85
11.2.2.2 Free Radical Scavenger 86
11.2.2.3 Control of Enzymatic Browning 86
11.2.2.4 Dough Improver 87
11.2.3 Stability of Ascorbic Acid 87
11.2.4 Rationale for the Experiment 88
11.3 Apparatus and Instruments 88
11.4 Reagents and Materials 89
11.5 Procedures 89
11.5.1 Ascorbic Acid Standard Curve 89
11.5.2 Effect of pH on Ascorbic Acid Stability 89
11.5.3 Effects of Temperature, pH, and Cu2+ on the Stability of Ascorbic Acid 90
11.5.4 Effect of Cooking on the Ascorbic Acid Content of Cabbage 90
11.6 Problem Set 90
11.7 Study Questions 91
11.8 References 91
Answers to Problem Set 92
12 Hydrolytic Rancidity in Milk 93
12.1 Learning Outcomes 93
12.2 Introduction 93
12.2.1 The Copper Soap Solvent Extraction Method 94
12.3 Apparatus and Instruments 96
12.4 Reagents and Materials 96
12.5 Treatments and Controls 96
12.6 Procedures 97
12.6.1 Standard Curve 97
12.6.2 Free Fatty Acids in Milk 97
12.6.3 Calculations 97
12.7 Problem Set 98
12.8 Study Questions 98
12.9 References 98
12.10 Suggested Reading 98
Answers to Problem Set 99
13 Caffeine in Beverages 101
13.1 Learning Outcomes 101
13.2 Introduction 101
13.3 Apparatus and Instruments 103
13.4 Reagents and Materials 103
13.5 Operation of the HPLC 103
13.6 Procedures 104
13.6.1 Standard Curve 104
13.6.2 Caffeine in Soda and Energy Drinks 105
13.6.3 Caffeine in Coffee 105
13.6.4 Caffeine in Tea 105
13.7 Data Analysis 105
13.8 References 105
13.9 Suggested Reading 106
14 Color Additives 107
14.1 Learning Outcomes 107
14.2 Introduction 107
14.2.1 Binding to Wool 110
14.2.2 Removal from Wool 110
14.2.3 Solid-Phase Extraction (SPE) 110
14.2.4 Separation and Identification 111
14.3 Apparatus and Instruments 111
14.4 Reagents and Materials 112
14.5 Procedures 112
14.5.1 Qualitative Identification of Artificial Colors from Food Products 112
14.5.2 Separation and Identification of the Extracted Colors 113
14.5.3 Quantitative Analysis of FD&C Red Dye # 40 in Cranberry Juice 113
14.6 Study Questions 114
14.7 References 114
14.8 Suggested Reading 114
15 Plant Pigments 115
15.1 Learning Outcomes 115
15.2 Introduction 115
15.3 Apparatus and Instruments 119
15.4 Reagents and Materials 119
15.5 Procedures 120
15.5.1 Extraction and Separation of Lipid Soluble Plant Pigments 120
15.5.2 Extraction of Water Soluble Plant Pigments 120
15.5.3 Effect of pH on the Color of Water Soluble Plant Pigments 120
15.5.4 Demonstration 121
15.6 Study Questions 121
15.7 References 121
15.8 Suggested Reading 121
16 Meat Pigments 123
16.1 Learning Outcomes 123
16.2 Introduction 123
16.2.1 Meat Curing 125
16.2.2 Effect of Cooking on Meat Color 126
16.3 Apparatus and Instruments 127
16.4 Reagents and Materials 127
16.5 Procedures 127
16.5.1 Preparation and Spectral Analysis of Myoglobin, Oxymyoglobin, and Metmyoglobin 127
16.5.2 Preparation and Spectral Analysis of Nitric Oxide Myoglobin 128
16.5.3 Concentration of Metmyoglobin, Myoglobin, and Oxymyoglobin 128
16.5.4 Demonstration 129
16.6 Study Questions 129
16.7 References 129
16.8 Suggested Reading 130
17 Meat Tenderizers 131
17.1 Learning Outcomes 131
17.2 Introduction 131
17.3 Apparatus and Instruments 132
17.4 Reagents and Materials 133
17.5 Procedures 133
17.5.1 Preparation of Samples and Standards 133
17.5.1.1 Sample Treatments 133
17.5.1.2 Protein Extraction and Preparation for Electrophoresis 134
17.5.1.3 Preparation of SDS-PAGE Standards for Electrophoresis. 134
17.5.2 Electrophoresis 134
17.5.2.1 Loading and Running the Gel 134
17.5.2.2 Staining the Gel 134
17.5.3 Demonstration 134
17.6 Study Questions 134
17.7 References 135
17.8 Suggested Reading 135
18 Detection of Genetically Engineered Maize Varieties 137
18.1 Learning Outcomes 137
18.2 Introduction 137
18.2.1 Detection of a GE Protein by Immunoassay 140
18.2.2 Detection of a Trans Gene by PCR 141
18.3 Apparatus and Instruments 143
18.4 Reagents and Materials 143
18.5 Procedures 144
18.6 Study Questions 145
18.7 References 145
18.8 Suggested Reading 146
19 Food Emulsions and Surfactants 147
19.1 Learning Outcomes 147
19.2 Introduction 147
19.2.1 Emulsions 147
19.2.2 Surfactants 147
19.2.3 Surfactants in Food Systems 148
19.3 Part I - Butter Churning (Phase Inversion) 150
19.3.1 Materials and Methods 150
19.3.1.1 Materials for Buttermaking 150
19.3.1.2 Buttermaking Procedure 150
19.3.2 Study Questions 151
19.4 Part II - Margarine Manufacture (Use of Surfactant for Semi-solid Foods) 151
19.4.1 Materials and Methods 151
19.4.1.1 Materials for Margarine Manufacture 151
19.4.1.2 Manufacture Procedure 152
19.4.2 Study Questions 152
19.5 Part III - Dispersion of Eugenol in Water (Surfactant Solubilization Capacity) 152
19.5.1 Materials and Methods 153
19.5.1.1 Materials for Dispersion Experiment 153
19.5.1.2 Experimental Procedure 153
19.5.2 Study Questions 154
19.6 Part IV - Mayonnaise Stability 155
19.6.1 Materials and Methods 155
19.6.1.1 Materials for Mayonnaise Experiment 155
19.6.1.2 Experimental Procedure 155
19.6.2 Study Questions 156
19.7 References 156
19.8 Suggested Reading 158
Appendix I 159
Conversion Factors 159
Appendix II 161
Concentration 161
Definition 161
Suggested Reading 162
Appendix III 163
Acids, Bases, Buffers, and pH Measurement 163
Review of pH and Acid-Base Equilibria 163
Acids and Bases 163
Acid/Base Equilibria 163
The pH Scale 165
pK 165
Buffers: Functions and Uses 166
Problems 167
Choosing a Buffer System 169
Preparation of Buffers 171
Activity and Ionic Strength 173
pH Measurement 174
Making pH Measurements 175
References 176
Suggested Reading 176
Appendix IV 177
Spectrophotometry 177
Introduction 177
Operation of a Spectrophotometer 180
Notes for Operators 180
Problem Set 180
References 181
Answers to Problem Set 181
Appendix V 183
Chromatography 183
What Is Chromatography? 183
Chromatography Terminology 183
Types of Chromatography 184
Adsorption Chromatography (AC) 185
Liquid-Liquid Partition Chromatography (LLPC) 185
Bonded Phase Chromatography (BPC) 185
Ion-Exchange Chromatography (IEC) 185
Gel Permeation Chromatography (GPC) 185
High-Performance Liquid Chromatography 186
The HPLC System 187
References 188
Suggested Reading 189
Appendix VI 191
Electrophoresis 191
Introduction 191
References 195
Suggested Reading 196
Appendix VII 197
Glossary 197
