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MAPS PREFACE CONTRIBUTORS ACKNOWLEDGEMENTS LIST OF NEW ENTRIES COMPLETE LIST OF ENTRIES BY SUBJECT NOTE TO THE READER ALPHABETICAL ENTRIES COMPLETE LIST OF CONTROLLED APPELLATIONS AND THEIR PERMITTED GRAPE VARIETIES VINEYARD AREA, WINE PRODUCTION, AND PER CAPITA WINE CONSUMPTION BY COUNTRY PICTURE CREDITS

International competition within the wine market, consumer demands for newer styles of wines and increasing concerns about the environmental sustainability of wine production are providing new challenges for innovation in wine fermentation. Within the total production chain, the alcoholic fermentation of grape juice by yeasts is a key process where winemakers can creatively engineer wine character and value through better yeast management and, thereby, strategically tailor wines to a changing market. This review considers the importance of yeast ecology and yeast metabolic reactions in determining wine quality, and then discusses new directions for exploiting yeasts in wine fermentation. It covers criteria for selecting and developing new commercial strains, the possibilities of using yeasts other than those in the genus of Saccharomyces, the prospects for mixed culture fermentations and explores the possibilities for high cell density, continuous fermentations.

The perception of wine flavor and aroma is the result of a multitude of interactions between a large number of chemical compounds and sensory receptors. Compounds interact and combine and show synergistic (i.e., the presence of one compound enhances the perception of another) and antagonistic (a compound suppresses the perception of another) interactions. The chemical profile of a wine is derived from the grape, the fermentation microflora (in particular the yeast Saccharomyces cerevisiae), secondary microbial fermentations that may occur, and the aging and storage conditions. Grape composition depends on the varietal and clonal genotype of the vine and on the interaction of the genotype and its phenotype with many environmental factors which, in wine terms, are usually grouped under the concept of "terroir" (macro, meso and microclimate, soil, topography). The microflora, and in particular the yeast responsible for fermentation, contributes to wine aroma by several mechanisms: firstly by utilizing grape juice constituents and biotransforming them into aroma- or flavor-impacting components, secondly by producing enzymes that transform neutral grape compounds into flavor-active compounds, and lastly by the de novo synthesis of many flavor-active primary (e.g., ethanol, glycerol, acetic acid, and acetaldehyde) and secondary metabolites (e.g., esters, higher alcohols, fatty acids). This review aims to present an overview of the formation of wine flavor and aroma-active components, including the varietal precursor molecules present in grapes and the chemical compounds produced during alcoholic fermentation by yeast, including compounds directly related to ethanol production or secondary metabolites. The contribution of malolactic fermentation, ageing, and maturation on the aroma and flavor of wine is also discussed.

The aim of this work was to increase the knowledge of the peptide fraction in musts and wines, of which there are very few publications in literature. For this purpose, the peptides in four varietal sparkling wines manufactured industrially following the Champenoise method were analyzed by HPLC. Samples of the musts, base wines, and sparkling wines were taken after 9, 12, 15, and 18 months of aging on yeast lees. The peptides of the fractions with molecular weights higher and lower than 700, obtained by fractionation on Sephadex G-10, were separated by reversed-phase HPLC. The chromatographic profiles of the peptides in the wines were similar. During the manufacture of the base wines, there was an increase in the peptides studied. During aging, peptides were released and then degraded by the yeast enzymes. Keywords: Peptides; HPLC; must; wine; sparkling wine; cava

Biogenic amines (BA) are a group of organic nitrogenous compounds formed and degraded by the metabolism of living organisms (microorganisms, plants and animals). The main BA associated with wine are putrescine, histamine, tyramine and cadaverine, followed by phenylethylamine, spermidine, spermine, agmatine and tryptamine. The variability in the BA content of wine could be explained on the basis of differences in the winemaking process, time and storage conditions, raw material quality, and possible microbial contamination during winery operations. BA are formed by decarboxylation of the corresponding amino acids by microorganisms through substrate-specific decarboxylase enzymes. This property is usually strain dependent. Decarboxylase enzymes are generally induced at acidic pH and therefore they have a possible role in maintaining pH homeostasis or extending the microbial growth period by detoxification of the extracellular medium. The presence of these compounds is considered by some authors a fundamental parameter for the detriment of wine.

Wine has one of the broadest chemical profiles, and the common oenological practice of adding the antioxidant and antimicrobial sulfur dioxide has a major impact on its metabolomic fingerprint. In this study, we investigated novel discovered oenological reactions primarily occurring between wine metabolites and sulfur dioxide. The sulfonated derivatives of epicatechin, procyanidin B2, indole acetic acid, indole lactic acid and tryptophol were synthesized and for the first time quantified in wine. Analysis of 32 metabolites in 195 commercial wines (1986-2016 vintages) suggested that sulfonation of tryptophan metabolites characterised white wines, in contrast to red wines, where sulfonation of flavanols was preferred. The chemical profile of the oldest wines was strongly characterised by sulfonated flavanols and indoles, indicating that could be fundamental metabolites in explaining quality in both red and white aged wines. These findings offer new prospects for more precise use of sulfur dioxide in winemaking.

Wine is one of the most consumed beverages around the world. It is composed of alcohols, sugars, acids, minerals, proteins and other compounds, such as organic acids and volatile and phenolic compounds (also called polyphenols). Polyphenols have been shown to be highly related to both (i) wine quality (color, flavor, and taste) and (ii) health-promoting properties (antioxidant and cardioprotective among others). Polyphenols can be grouped into two big families: (i) Flavonoids, including anthocyanidins, flavonols, flavanols, hydrolysable and condensed tannins, flavanones, flavones and chalcones; and (ii) Non-flavonoids, including hydroxycinnamic acids, hydroxybenzoic acids, stilbenes, tyrosol and hydroxytyrosol. Each group affects in some way the different properties of wine to a greater or a lesser extent. For that reason, the phenolic composition can be managed to obtain singular wines with specific, desirable characteristics. The current review presents a summary of the ways in which the phenolic composition of wine can be modulated, including (a) invariable factors such as variety, field management or climatic conditions; (b) pre-fermentative strategies such as maceration, thermovinification and pulsed electric field; (c) fermentative strategies such as the use of different yeasts and bacteria; and (d) post-fermentative strategies such as maceration, fining agents and aging. Finally, the different extraction methods and analytical techniques used for polyphenol detection and quantification have been also reviewed.