Understanding wine chemistry

Wine chemistry inspires and challenges with its complexity, and while this is intriguing, it can also be a barrier to further understanding. The topic is demystified in Understanding Wine Chemistry, which explains the important chemistry of wine at the level of university education, and provides an accessible reference text for scientists and scientifically trained winemakers alike. Understanding Wine Chemistry: Summarizes the compounds found in wine, their basic chemical properties and their contribution to wine stability and sensory properties Focuses on chemical and biochemical reaction mechanisms that are critical to wine production processes such as fermentation, aging, physiochemical separations and additions Includes case studies showing how chemistry can be harnessed to enhance wine color, aroma, flavor, balance, stability and quality. This descriptive text provides an overview of wine components and explains the key chemical reactions they undergo, such as those controlling the transformation of grape components, those that arise during fermentation, and the evolution of wine flavor and color. The book aims to guide the reader, who perhaps only has a basic knowledge of chemistry, to rationally explain or predict the outcomes of chemical reactions that contribute to the diversity observed among wines. This will help students, winemakers and other interested individuals to anticipate the effects of wine treatments and processes, or interpret experimental results based on an understanding of the major chemical reactions that can occur in wine. INDICE: Foreword xiii .Preface xv .Introduction xvii .The chemical diversity of wine xvii .What is wine? xvii .Chemical reactions in wine xx .Chemistry as a historical record xxi .The chemical senses and wine flavor xxi .References xxiv .Part A Wine Components and Their Reactions 1 .1 Water and Ethanol 3 .1.1 Introduction 3 .1.2 Chemical and physical properties of water 3 .1.3 Properties of ethanol and ethanol water mixtures 4 .1.4 Typical ethanol concentrations in wines 6 .1.5 Sensory effects of ethanol 7 .References 9 .2 Carbohydrates 11 .2.1 Introduction 11 .2.2 Nomenclature, representation, and occurrence of sugars 11 .2.3 Physical, chemical, and sensory properties of sugars 14 .2.4 Polysaccharides 17 .References 18 .3 Acids 19 .3.1 Introduction 19 .3.2 Organic acids in wine 19 .3.3 Organic acids, pH, and wine acidity 21 .3.4 Acid adjustments 28 .3.5 General roles of organic acids and pH in wine reactions 31 .3.6 Sensory effects of acids 31 .References 32 .4 Minerals 34 .4.1 Introduction 34 .4.2 Origins of metals in wine 35 .4.3 Reactions involving metals 35 .4.4 Sensory effects of metals 37 .4.5 Metals and wine authenticity 37 .References 38 .5 Amines, Amino Acids, and Proteins 40 .5.1 Introduction 40 .5.2 Chemistry of amines 40 .5.3 Amino acids and related major nitrogenous compounds in wines 41 .5.4 Nitrogenous compounds with health effects 44 .5.5 Odor–active amines 45 .References 48 .6 Higher Alcohols 51 .6.1 Introduction 51 .6.2 Properties of higher alcohols 51 .6.3 Origins and concentrations of higher alcohols 52 .6.4 Six–carbon (C6) alcohols 53 .6.5 Methanol 54 .References 55 .7 Esters 57 .7.1 Introduction 57 .7.2 Chemistry of esters 57 .7.3 Esters in grapes 60 .7.4 Esters formed during winemaking and storage 60 .7.5 Sensory effects 65 .References 66 .8 Isoprenoids 68 .8.1 Introduction 68 .8.2 General chemical and sensory properties of isoprenoids 68 .8.3 Monoterpenoids 69 .8.4 Sesquiterpenoids 73 .8.5 C13–Norisoprenoids 74 .References 76 .9 Aldehydes, Ketones, and Related Compounds 79 .9.1 Introduction 79 .9.2 Acetaldehyde 80 .9.3 Short and medium chain aldehydes 80 .9.4 Complex carbonyls 84 .9.5 Carbonyl reactivity 85 .References 86 .10 Thiols and Related Sulfur Compounds 88 .10.1 Introduction 88 .10.2 Varietal sulfur aroma compounds polyfunctional thiols 91 .10.3 Fermentative sulfur aroma compounds 93 .10.4 Other sulfur–containing aroma compounds 94 .Chemical principles: nucleophiles and electrophiles 95 .References 97 .11 Introduction to Phenolics 99 .11.1 Introduction 99 .11.2 Non–flavonoids 102 .11.3 Flavonoids 103 .References 104 .12 Volatile Phenols 105 .12.1 Introduction 105 .12.2 Structure and chemical properties 105 .12.3 Concentrations in wine and sensory effects 107 .12.4 Origins in wine and effects on volatile phenol profile 107 .References 110 .13 Non–flavonoid Phenolics 112 .13.1 Introduction 112 .13.2 Hydroxycinnamates 112 .13.3 Hydroxybenzoic acids 113 .13.4 Stilbenes 114 .References 115 .14 Flavan–3–ols and Condensed Tannin 117 .14.1 Introduction 117 .14.2 Monomeric catechins 117 .14.3 Oligomeric proanthocyanidins and polymeric condensed tannins 119 .14.4 Sensory effects 122 .Chemical principles: electrophilic aromatic substitution 123 .References 125 .15 Flavonols 127 .15.1 Introduction 127 .15.2 Concentrations of flavonols 127 .15.3 Effects of growing conditions and winemaking 129 .References 129 .16 Anthocyanins 131 .16.1 Introduction 131 .16.2 Structures and forms 131 .16.3 Non–covalent interactions: co–pigmentation 133 .16.4 Bisulfite bleaching 134 .16.5 Wine pigments 135 .References 138 .17 Sulfur Dioxide 140 .17.1 Introduction and terminology 140 .17.2 Acid base chemistry of SO2 141 .17.3 Sulfonate adducts, bound SO2, and antioxidant effects 143 .17.4 Typical sources and concentrations of SO2 in wine 146 .17.5 Measurement of molecular, free, and total SO2 146 .17.6 Sensory effects 147 .References 148 .18 Taints, Off–flavors, and Mycotoxins 149 .18.1 Introduction 149 .18.2 Common wine taints 150 .18.3 Off–flavors in wine 155 .References 156 .Part B Chemistry of Wine Production Processes 159 .19 Outline of Wine Production 161 .19.1 Introduction 161 .19.2 Basic workflow 161 .19.3 Processes involved 164 .19.4 Tanks and fermenters 166 .19.5 Beyond fermentation 169 .19.6 Specialty wines 169 .References 170 .20 Grape Must Composition Overview 172 .20.1 Sampling 172 .20.2 Sugars 172 .20.3 Acids 173 .20.4 Phenolics 174 .20.5 Nitrogen species 175 .20.6 Lipids and waxes 175 .20.7 Minerals and vitamins 176 .20.8 Isoprenoids 176 .20.9 Insoluble materials 176 .References 177 .21 Maceration and Extraction of Grape Components 179 .21.1 Introduction 179 .21.2 Pre–fermentative treatments 183 .21.3 Maceration treatments during fermentation 186 .21.4 Post–fermentation maceration 189 .References 190 .22 The Biochemistry of Wine Fermentations 194 .22.1 Glycolysis 195 .22.1.1 Introduction 195 .22.1.2 Glycolysis and alcoholic fermentation 196 .22.1.3 Glyceropyruvic fermentation 198 .22.1.4 Succinic acid and other Krebs cycle intermediates 200 .22.1.5 Consequences of glycolysis on wine chemistry 202 .References 204 .22.2 Fatty Acid Metabolism 205 .22.2.1 Introduction 205 .22.2.2 Long–chain fatty acid metabolism 205 .22.2.3 Mid–chain fatty acids (MCFAs) and ethyl esters 209 .22.2.4 Increasing MCFA and their ethyl esters in winemaking 211 .References 212 .22.3 Amino Acid Metabolism 214 .22.3.1 Introduction 214 .22.3.2 Nitrogen uptake and catabolite repression 214 .22.3.3 Amino acid anabolism, catabolism, and carbon skeletons 216 .22.3.4 Higher alcohol formation 216 .22.3.5 Acetate ester formation 218 .22.3.6 YAN in the winery requirements, approaches, and consequences 219 .References 221 .22.4 Sulfur Metabolism 223 .22.4.1 Introduction 223 .22.4.2 Sulfide production and assimilation 223 .22.4.3 Nitrogen sources and H2S formation 226 .22.4.4 Timing of formation and residual H2S 227 .References 228 .22.5 Bacterial Fermentation Products 230 .22.5.1 Introduction 230 .22.5.2 Lactic acid bacteria 230 .22.5.3 Spoilage of wine by bacteria 235 .References 237 .23 Grape–Derived Aroma Precursors 239 .23.1 Glycosidic Precursors to Wine Odorants 240 .23.1.1 Introduction 240 .23.1.2 Formation of glycosidic aroma precursors in grape berries 242 .23.1.3 Glycosidic aroma precursors extraction 245 .23.1.4 Hydrolysis of glycosidic aroma precursors mechanisms 246 .23.1.5 Hydrolysis of glycosides under fermentation and aging conditions 249 .References 252 .23.2 S–Conjugates 256 .23.2.1 Introduction 256 .23.2.2 Formation of S–conjugate precursors in berries and juice 257 .23.2.3 Conversion of S–conjugate precursors during fermentation 259 .23.2.4 Mass balance and alternative pathways to volatile thiol formation 262 .References 263 .23.3 Conversion of Variety Specific Components, Other 265 .23.3.1 Introduction 265 .23.3.2 Polyunsaturated fatty acid precursors of C6 compounds 265 .23.3.3 Hydroxycinnamic acids, Brettanomyces, and volatile phenols 269 .23.3.4 S–methylmethionine and dimethyl sulfide 273 .References 275 .24 Wine Oxidation 278 .24.1 Introduction 278 .24.2 Redox reactions 278 .24.3 The central tenets of wine oxidation 280 .24.4 The central tenets of quinone reactions 283 .24.5 The central tenets of the Fenton reaction and byproducts 288 .References 291 .25 Topics Related to Aging 294 .25.1 Introduction 294 .25.2 Reactions involving red wine pigments 294 .25.3 Hydrolytic and pH–dependent reactions 298 .25.4 Activation energy and temperature effects on aging 303 .25.5 Effects of oak storage 304 .25.6 Sensory effects of different aging conditions 309 .Closure performance 312 .References 313 .26 The Chemistry of Post–fermentation Processing 318 .26.1 Cold Stabilization 319 .26.1.1 Introduction 319 .26.1.2 KHT crystal properties and solubility 320 .26.1.3 Critical factors for KHT precipitation 322 .26.1.4 Testing for KHT stability 325 .26.1.5 Treatments for preventing KHT precipitation 327 .26.1.6 CaT and related precipitates 330 .References 330 .26.2 Fining 332 .26.2.1 Introduction 332 .26.2.2 Tannin fining with proteins 333 .26.2.3 Protein fining with bentonite 338 .26.2.4 Miscellaneous fining and related treatments 341 .References 343 .26.3 Particle Filtration and Reverse Osmosis 346 .26.3.1 Introduction 346 .26.3.2 Definitions, principles, and characteristics of winery filtration 347 .26.3.3 Filtration and fouling 350 .26.3.4 Reverse osmosis 354 .26.3.5 Sensory effects of filtration 355 .References 357 .26.4 Distillation 359 .26.4.1 Introduction 359 .26.4.2 Vapor liquid equilibria 360 .26.4.3 Batch and continuous distillation 365 .26.4.4 Spirit composition and cask maturation 373 .References 375 .27 Additives and Processing Aids 377 .27.1 Introduction 377 .27.2 Regulations and terminology 377 .27.3 Additives and processing aids: functions and comparison across regions 379 .References 382 .Part C Case Studies: Recent Advances in Wine Chemistry 383 .28 Authentication 385 .28.1 Introduction 385 .28.2 Fraud categories and detection approaches 385 .28.3 Stable isotope ratio analysis to detect glycerol adulteration 387 .28.4 Future challenges in wine authentication 389 .References 390 .29 Optimizing White Wine Aromas 392 .29.1 Introduction 392 .29.2 Enhancement of varietal thiols 392 .29.3 Cofermentation and spontaneous fermentation 394 .References 395 .30 Appearance of Reduced Aromas during Bottle Storage 397 .30.1 Introduction 397 .30.2 Potential latent sources of compounds responsible for reduced aromas 397 .References 399 .31 Grape Genetics, Chemistry, and Breeding 400 .31.1 Introduction 400 .31.2 Breeding new varieties 400 .31.3 Genetics and selection 402 .References 403 .32 Analytical Innovations and Applications 404 .32.1 Introduction 404 .32.2 Typical approaches to wine analysis 405 .32.3 Multivariate data analysis and chemometrics 408 .32.4 Chemometrics in practice rapid methods for wine analysis 409 .32.5 Targeted and untargeted metabolomics of wine 413 .References 414 .33 New Approaches to Tannin Characterization 417 .33.1 Introduction 417 .33.2 The challenge of astringency subclasses 418 .References 418 .Index 420

• ISBN: 9781118627808
• Editorial: Wiley–Blackwell
• Encuadernacion: Tela
• Páginas: 470
• Fecha Publicación: 19/08/2016
• Nº Volúmenes: 1
• Idioma: Inglés