Handbook of Enology, Volume 2. Pascal Ribéreau-Gayon

2FIGURE 2.1 Structure of ethanol and definition of the alcohol function.FIGURE 2.2 Reaction between hydrogen sulfide and ethanol.FIGURE 2.3 Oxidation–reduction equilibrium of the thiol/disulfide system.FIGURE 2.4 Biosynthesis of higher alcohols, according to Ehrlich.FIGURE 2.5 Mechanism for the formation of acrolein by double dehydration of ...FIGURE 2.6 Oxidation–reduction equilibria of 2‐3‐butanediol.FIGURE 2.7 Esterification equilibrium of an alcohol.FIGURE 2.8 Biosynthesis mechanism of fatty acids.FIGURE 2.9 Formation of an acetal.FIGURE 2.10 Acetalization of acetaldehyde and formation of diethoxyethane.FIGURE 2.11 Formation of γ‐butyrolactone.FIGURE 2.12 Formation of sotolon in wines.FIGURE 2.13 β ‐Methyl‐γ‐octalactone.

      3 Chapter 3FIGURE 3.1 Fischer projection of glucose and fructose.FIGURE 3.2 Intramolecular hemiacetalization reaction with formation of two s...FIGURE 3.3 Conformation equilibrium of α‐D‐glucopyranose.FIGURE 3.4 Epimerization equilibrium of α‐D‐glucopyranose and β‐D‐...FIGURE 3.5 Fischer and Haworth representations of β‐D‐glucofuranose.FIGURE 3.6 Fischer projections of the main aldopentoses.FIGURE 3.7 Cyclic structures of α‐D‐xylopyranose and α‐D‐ribofuran...FIGURE 3.8 Formation of glyceraldehyde 3‐phosphate and dihydroxyacetone 1‐ph...FIGURE 3.9 Formation of sucrose from glucose and fructose.FIGURE 3.10 Aldimine and ketimine formation mechanism by the addition of an ...FIGURE 3.11 Breakdown, according to the Strecker reaction, of an aldimine re...FIGURE 3.12 Osazone formation mechanism by the addition of three phenylhydra...FIGURE 3.13 Methyl D‐glucopyranoside formation mechanism.FIGURE 3.14 Derivatization of α‐ and β‐methoxy‐1‐glucopyranoses in...FIGURE 3.15 Examples of O‐glycosides significant in enology.FIGURE 3.16 Basic structure of α‐homogalacturonan. Chain of partially m...FIGURE 3.17 Structure of a rhamnogalacturonan I (RG‐I). α‐D‐GalAp, α...FIGURE 3.18 Proposed structural model for acidic pectic substances in grapes...FIGURE 3.19 Structure of arabinogalactans in pectic substances (Brillouet et...FIGURE 3.20 Structure of arabinans in pectic substances (Villetaz et al., 1...FIGURE 3.21 Structure of rhamnogalacturonan II (RG‐II) (Doco and Brillouet, ...FIGURE 3.22 Production of exocellular polysaccharides by commercial yeast st...FIGURE 3.23 Influence of temperature on the production of exocellular polysa...FIGURE 3.24 Model of the molecular structure of exocellular mannoproteins pr...FIGURE 3.25 Molecular structure of the exocellular β‐glucan produced by...FIGURE 3.26 Molecular structure of the exocellular β‐(1,3:1,2)‐glucan p...

      4 Chapter 4FIGURE 4.1 Iron reactions in aerated wines (Ribéreau‐Gayon et al., 1976). Co...FIGURE 4.2 The various forms of ferric iron after saturation with oxygen, in...FIGURE 4.3 Phytic acid.FIGURE 4.4 Protein cross‐linking by copper and copper casse.

      5 Chapter 5FIGURE 5.1 Structure of pyrazines.FIGURE 5.2 The L configuration of an α‐amino acid.FIGURE 5.3 Forms of α‐amino acid in an aqueous solution.FIGURE 5.4 (A) GSH concentrations in different parts of Sauvignon blanc berr...FIGURE 5.5 Structure of glutathione and its reaction with quinones produced ...FIGURE 5.6 Urea cycle and its relationship with the Krebs cycle. Comparative...FIGURE 5.7 Role of arginine in biogenic amine synthesis.FIGURE 5.8 Separation of proteins from Sauvignon Blanc must and wine by elec...FIGURE 5.9 Separating the proteins in Sauvignon Blanc must by chromatofocusi...FIGURE 5.10 Separating proteins (peaks A, B, C, D) and polysaccharides (peak...FIGURE 5.11 Separating proteins in Sauvignon Blanc wine by capillary electro...FIGURE 5.12 Changes in protein concentrations in must during ripening accord...FIGURE 5.13 Changes in the protein concentration of Sauvignon Blanc must dur...FIGURE 5.14 Effect of destemming on the protein concentration of Sauvignon B...FIGURE 5.15 Development of protein stability in a dry Sauvignon Blanc wine b...FIGURE 5.16 Heat stability of various proteins in a Sauvignon Blanc wine sep...FIGURE 5.17 Influence of the quantity of bentonite used to stabilize a wine ...FIGURE 5.18 Effect of adding (250 mg/l) mannoproteins extracted by enzymes f...FIGURE 5.19 Sequence of amino acids 151–200 in S. cerevisiae invertase. The ...FIGURE 5.20 Changes in the dose of bentonite necessary to stabilize a dry Sa...FIGURE 5.21 Changes in the MP32 concentration of a dry Sauvignon Blanc wine ...

      6 Chapter 6FIGURE 6.1 Phenolic acids in grapes and wine.FIGURE 6.2 Derivatives of cinnamic acids and tartaric acid. R₁ = H, p‐coumar...FIGURE 6.3 7‐O‐β‐D‐Glucosyl‐p‐coumaric acid (Biau, 1996).FIGURE 6.4 Main volatile phenols in wine.FIGURE 6.5 Alcohols and coumarins.FIGURE 6.6 3,5,4′‐Trihydroxystilbene (resveratrol).FIGURE 6.7 Flavonoids: (a) flavone (R₃ = H) and flavonol (R₃ = OH) and (b) f...FIGURE 6.8 Quercetin 3‐O‐rhamnoside.FIGURE 6.9 Structure of anthocyanidins in grapes and wine.FIGURE 6.10 Structure of (a) anthocyanin 3‐monoglucoside and (b) anthocyanin...FIGURE 6.11 Structure of anthocyanin 3,5‐diglucosides (

; see Figure 6.9).FIGURE 6.12 Structure of castavinols resulting from fixing diacetyl (CH₃–CO–...FIGURE 6.13 Structure of phenolic acids (a and b) and ellagitannins (c and d...FIGURE 6.14 Structure of flavan‐3‐ol precursors of procyanidins and tannins....FIGURE 6.15 Structure and nomenclature of B‐type dimeric procyanidins (de Fr...FIGURE 6.16 Structure of the dimeric procyanidin A₂ (Vivas and Glories, 1996...FIGURE 6.17 Structures of condensed proanthocyanidins.FIGURE 6.18 The various forms of anthocyanins (

; see Figure 6.9) (Brouillar...FIGURE 6.19 Changes in the proportion of different forms of anthocyanins acc...FIGURE 6.20 Bleaching of anthocyanin solutions due to pH and sulfur dioxide....FIGURE 6.21 Interaction between proteins and polyphenols (Asano et al., 1982...FIGURE 6.22 Model of protein precipitation by polyphenols (Haslam, 1981).FIGURE 6.23 Breakdown of dimeric procyanidins by acid catalysis (de Freitas,...FIGURE 6.24 Structure of 4‐α‐ethylthioflavan‐3‐ol derived from (+)‐cate...FIGURE 6.25 Diagram of the various hypothetical pathways for the oxidation o...FIGURE 6.26 Example of tannin polymerization: (a) organized polymerization o...FIGURE 6.27 Diagram of heterogeneous polymerization of procyanidins (P) in t...FIGURE 6.28 Polymerization of flavanols in the presence of glyoxylic acid.FIGURE 6.29 Structure of three pigments produced by adding (a) vinylphenol, ...FIGURE 6.30 Direct A–T condensation of anthocyanins and tannins (

; see Figu...FIGURE 6.31 Direct T–A type condensation of procyanidins and anthocyanins (

FIGURE 6.32 Reaction between catechin and malvidin 3‐O‐glucoside in an acidi...FIGURE 6.33 Red‐violet complex produced by the condensation of malvidin 3‐O‐...FIGURE 6.34 HPLC chromatogram of an anthocyanin solution extracted from Merl...FIGURE 6.35 Simplified method for fractionating