چربی‌های غذایی: شیمی، طعم و بافت (سری سمپوزیوم ACS)

Edible oils from vegetable and animal sources are composed primarily of triacylglycerols and to a lesser extent minor components referred to as unsaponifiable matter. During processing of oils and as a result of reactions in production of structured and other novel lipids many of these components are removed and hence the relative stability of the preparation is compromised. Presence of chlorophyll in the oils, both endogenous and in the additives, resulted in enhanced production of odor-active aldehydes under fluorescent light. However, simultaneous removal of non-triacylglycerol components reduced the stability of oils under Schaal oven conditions. In enzymic acidolysis of algal oils with capric acid we found that the resultant oils were much less stable than their unaltered counterparts despite a decrease in the degree of unsaturation of the products. Experiments carried out in the absence of any enzyme showed that removal of endogenous antioxidants was indeed responsible for this phenomenon. Fats and oils provide a concentrated source of energy and essential fatty acids as well as fat soluble vitamins and other minor components. Lipids also serve as an important constituent of cell walls. In foods, lipids provide flavor, texture and mouthfeel to products. In addition, fats and oils serve as a heating medium and are important in the generation of aroma, some of which arise from bk-2005-0920_cover 1 bk-2005-0920.fw001 2 Title Page 2 Half Title Page 4 Copyright 5 Foreword 6 bk-2005-0920.pr001 7 Preface 7 bk-2005-0920.ch001 10 Chapter 1 Importance of Non-Triacylglycerols to Flavor Quality of Edible Oils 10 Triacylglycerols 12 Stability of Edible Oils 14 Degree of Unsaturation 14 Non-triacylyglycerols Constituents 15 Effect of Processing on Non-Triacylyglycerols Components and Stability of Oils 20 References 25 bk-2005-0920.ch002 26 Chapter 2 Formation of Odor-Active Carbonyls in Self-Assembly Structures of Phospholipids 26 Introduction 26 Experimental 28 Materials 28 Sample Preparation and Cleanup 28 Chromatographic Techniques 29 Results and Discussion 30 Odor-Active Compounds 30 Formation of Selected Odorants from PC and PE 32 Factors Affecting the Degradation of Phospholipids 35 References 41 bk-2005-0920.ch003 42 Chapter 3 The Effects of Diet, Breed, and Age of Animal at Slaughter on the Volatile Compounds of Grilled Beef 42 Experimental 43 Meat Production and Cooking Conditions 43 Analysis of Volatile Compounds 44 Fatty Acid Analysis 45 Statistical Analysis 45 Results and Discussion 46 Volatile Compounds 46 Fatty acids 50 Conclusions 54 Acknowledgements 54 References 54 bk-2005-0920.ch004 56 Chapter 4 Flavor Release from French Fries 56 Introduction 56 Materials and Methods 57 Materials 57 General Setup 57 Identification of Released Flavors 58 In vivo Flavor Release in Exhaled Breath 58 In vitro Flavor Release in the Mouth Model System 58 Statistical Analysis 59 Results and Discussion 59 Identification of observed compounds 59 Effect of frying time on Imax and tmax 59 Effect of salt addition on Imax and tmax 63 Conclusions 63 References 63 bk-2005-0920.ch005 68 Chapter 5 Flavor Release from Food Emulsions Containing Different Fats 68 Experimental 69 Preparation of the Food Model Emulsions 69 Solid - Phase Microextraction (SPME) coupled with GC - MS (SIM mode) analysis 70 Results and Discussion 71 Flavor release analysis by solid − phase microextraction 71 Vapor-oil partition coefficients 74 Determination of the melting behavior of pure fats and food model emulsions by differential scanning calorimetry (DSC) 74 Discussion 76 Acknowledgment 78 References 78 bk-2005-0920.ch006 80 Chapter 6 Changes in Key Odorants of Sheep Meat Induced by Cooking 80 Materials and Methods 82 Results and Discussion 82 Key odorants in cooked lean sheep meat 82 Key odorants in raw lean sheep meat 84 Quantitative measurements 86 Key odorants in sheep tissue fat 88 References 89 bk-2005-0920.ch007 91 Chapter 7 Differential Retention of Emulsion Components in the Mouth after Swallowing: ATR FTIR Measurements of Oral Coatings 91 Materials and methods 92 Results and Discussion 93 Development of the method 93 The composition of the oral coating after mastication of mayonnaise samples 95 Acknowledgement 98 References 98 bk-2005-0920.ch008 99 Chapter 8 The Role of Fats in Friction and Lubrication 99 Lubrication by saliva 101 Experiment 1 101 Results 104 Experiment 2 105 Conclusions 106 References 107 bk-2005-0920.ch009 108 Chapter 9 Prediction of Creamy Mouthfeel Based on Texture Attribute Ratings of Dairy Desserts 108 Experimental 109 Results and Discussion 114 Acknowledgement 119 References 119 bk-2005-0920.ch010 121 Chapter 10 Effects of Structure Breakdown on Creaminess in Semisolid Foods 121 Materials and Methods 124 Effects of Inhibiting α-amylase on Sensory Ratings 124 Sensory Time Intensity Measurements 124 Microstructural analysis by confocal scanning laser microscopy 125 Results and Discussion 126 Fat surfacing 126 Mechanism of fat surfacing 127 Inhibition of α-amylase activity using an α-amylase inhibitor 128 Acknowledgements 132 References 133 bk-2005-0920.ch011 135 Chapter 11 Chemistry and Rheology of Cheese 135 Cheese Chemistry 136 Lipids 136 Protein 136 Ripening 137 Cheese Rheology 139 Texture Profile Analysis (TPA) 139 Uniaxial Compression 139 Dynamic Tests 140 Torsion Tests 140 Transient Tests 140 Application: Low-Fat Mozzarella 141 Acknowledgments 142 References 142 bk-2005-0920.ch012 144 Chapter 12 How Lipids Influence Flavor Perception 144 Introduction 144 Effect of lipids on aroma release and perception 145 Effect of lipids on phase partitioning 145 Effect of lipids on mass transport 147 Effect of lipids on taste perception 153 Effect of lipids on mouthfeel 153 Effect of lipids on total flavor 154 References 155 bk-2005-0920.ch013 158 Chapter 13 Release of Flavor from Emulsions under Dynamic Sampling Conditions 158 Materials and Methods 159 Gas Phase Analysis 159 Sample Preparation and Consumption 160 Results and Discussion 160 Flavor Delivery From Yogurt 160 Flavor Delivery From Simple Solutions: Profile Shape 162 Flavor Delivery From Simple Solutions: Profile Intensity 163 The Effect Of The Partition Coefficient On Mass Transfer 165 Conclusions 166 Acknowledgement 168 References 168 bk-2005-0920.ch014 169 Chapter 14 Fat Reduction in Foods: Microstructure Control of Oral Texture, Taste, and Aroma in Reduced Oil Systems 169 Introduction 170 Explanation of the different levels in the business model 170 Integrated Sensory (or Consumer) Response Modelling (ISRM) 172 ISRM1: Identification of sensory effects of fat replacement which have consumer relevance 173 ISRM2. Qualitative analysis of the physics relevant to the oral processes during consumption of the spread/bread system 176 ISRM3-4. Measurable physical properties relevant to oral processes involved in mayonnaise consumption 179 ISRM5. Experimental characterization of wide ranges within a food product category 179 ISRM6. Quantitative models of sensory or consumer preference data 184 ISRM7. Validation contributing to mechanistic understanding and microstructure control 184 Conclusions 186 References 187 bk-2005-0920.ch015 188 Chapter 15 Effect of Composition of Triacylglycerols on Aroma Volatility: Application to Commercial Fats 188 Experimental 189 Model and complex lipids 189 Lipid characterization 190 Gas chromatographic analysis 191 Emulsions 191 Static headspace analysis 191 Statistical analysis 192 Results and Discussion 192 Effect of triacylglycerol composition on aroma volatility 192 Applications to complex lipids and emulsions 196 Conclusions 200 Acknowledgements 200 References 200 bk-2005-0920.ch016 202 Chapter 16 Fatty Acid and Volatile Flavor Profiles of Textured Partially Defatted Peanut 202 Textured peanut from extrusion processing 203 Fatty acid profile and cardiovascular health 203 Volatile flavor compounds 204 Objectives of study 204 Materials and Methods 205 Experimental design 205 Preparation of textured peanut 205 Evaluation of moisture content of textured peanut 206 Evaluation of fatty acid profile of textured peanut 206 Evaluation of volatile flavor compounds of textured peanut 206 Data analysis 207 Results and discussion 207 Moisture Content of Textured Peanut 207 Fatty Acid Profile of Textured Peanut 208 Volatile Flavor Compounds in Textured Peanut 210 Summary and Significance of Findings 214 References 215 bk-2005-0920.ap001 217 Color Figure Inserts 217 bk-2005-0920.ix001 218 Author Index 218 bk-2005-0920.ix002 219 Subject Index 219 A 219 B 219 C 220 D 221 E 221 F 222 G 224 H 224 I 224 L 225 M 225 N 226 O 226 P 228 R 229 S 229 T 230 U 231 V 231 X 231 Y 232 Chemistry, Flavor, and Texture of Lipid-Containing Foods discusses the chemistry and functionality of fat in food sensory perception, and the underlying physicochemical and physiological properties and processes. Fats and oils profoundly affect our sensory perception and appreciation of foods. Fats and oils serve as a source of many flavor compounds, most of which result from oxidation of unsaturated fatty acids. The nose perceives these flavor molecules by chemoreception, and the texture of foods arerelated to their physicochemical characteristics and structure and thus are perceived by mechanoreception. However, the structural and physicochemical characteristics of fats and oils also strongly influence flavor release. Furthermore, recent studies suggest perception of fats and oils may also bemediated by chemoreception in the oral cavity. While fats and oils have beneficial ingredients because of their energy density, we should minimize their intake because obesity is a serious health risk. Additionally, some types of fat have been found to contribute to arteriosclerosis. Therefore, the food industry is particularly interested indeveloping foods that have the sensory and hedonic functionality with less fat.