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Polysaccharides present in grapes interact with wine sensory-active compounds (polyphenols and volatile compounds) via different mechanisms and can affect wine organoleptic qualities such as astringency, color and aroma. Studies on the role that grape polysaccharides play in wines are reviewed in this paper. First, the composition of grape polysaccharides and their changes during grape ripening, winemaking and aging are introduced. Second, different interaction mechanisms of grape polysaccharides and wine sensory-active compounds (flavanols, anthocyanins and volatiles) are introduced, and the possible effects on wine astringency, color and aroma caused by these interactions are illustrated. Finally, the control of the grape polysaccharide content in practice is discussed, including classical winemaking methods (applying different maceration enzymes, temperature control, co-fermentation, blending), modern vinification technologies (pulsed electric field, ultrasound treatment), and the development of new grape polysaccharide products. [ABSTRACT FROM AUTHOR]

Abstract: To develop a robust tool for Chinese commercial wines’ varietal, regional, and vintage authentication, phenolic compounds in 121 Chinese commercial dry red wines were detected and quantified by using high‐performance liquid chromatography triple‐quadrupole mass spectrometry (HPLC‐QqQ‐MS/MS), and differentiation abilities of principal component analysis (PCA), partial least squares discriminant analysis (PLS‐DA), and orthogonal partial least squares discriminant analysis (OPLS‐DA) were compared. Better than PCA and PLS‐DA, OPLS‐DA models used to differentiate wines according to their varieties (Cabernet Sauvignon or other varieties), regions (east or west Cabernet Sauvignon wines), and vintages (young or old Cabernet Sauvignon wines) were ideally established. The S‐plot provided in OPLS‐DA models showed the key phenolic compounds which were both statistically and biochemically significant in sample differentiation. Besides, the potential of the OPLS‐DA models in deeper sample differentiating of more detailed regional and vintage information of wines was proved optimistic. On the basis of our results, a promising theoretic design for wine authentication was further proposed for the first time, which might be helpful in practical authentication of more commercial wines. Practical Application: The phenolic data of 121 Chinese commercial dry red wines was processed with different statistical tools for varietal, regional, and vintage differentiation. A promising theoretical design was summarized, which might be helpful for wine authentication in practical situation. [ABSTRACT FROM AUTHOR]

• Compositional/structural characteristics of wine polysaccharides are introduced. • Enological factors affect the wine polysaccharide composition are discussed. • Polysaccharides affect wine organoleptic qualities via different mechanisms. • Analytical procedures for further researching wine polysaccharides are summarized. Wine quality is closely related to various compounds including polysaccharides, a class of crucial macromolecules that affect its chemical and physical properties by influencing the colloidal state or interacting with other compounds via non-covalent bonds. Herein, the composition and structural characteristics of the major polysaccharides identified in wine and the factors influencing their contents are briefly described. An improved understanding of the molecular mechanisms of wine polysaccharides and their practical applications on wine stability and organoleptic qualities is thoroughly discussed. The effects of polysaccharides on wine quality are significantly correlated with their structure and composition as well as wine matrix composition. Thus, to better understand the chemical complexity of polysaccharides, relevant analytical methods are systematically summarized and highlighted, which may ultimately lead to the development of novel winery guidelines. [ABSTRACT FROM AUTHOR]

• Blending for wine color improvement can be realized under different oxygen exposure. • The contribution of modifier wines can be anthocyanins, flavonols, or flavan-3-ols. • Modifier wine contributed flavan-3-ols lead to more color improvement visually. • Base wine with weak phenolic profile was more easily to be chromatically modified. Limited oxygenation and over-oxidation experiments were designed to compare the phenolic and chromatic characters of base wines Cabernet Franc (CF), Cabernet Sauvignon (CS), and their counterparts that blended with modifier wines Marselan (MA) and Petit Verdot (PV). In both limited oxygenation and over-oxidation conditions, all blend wines generally contained higher C* ab , a* and Red%, and lower h ab , b* and Yellow% than their base wine counterparts, because MA contributed flavonols (copigments) and anthocyanins, and PV contributed flavanols (anthocyanin derived pigments precursors). Chromatic changes that can be perceived by human eye (ΔE* ab) in CF based blend wines were more obvious than that of CS based blend wines, which indicate that base wine with lower phenolic concentrations and weak phenolic profiles (CF) might be more prone to be chromatically modified than base wine with higher phenolic concentrations and distinct phenolic profiles (CS). Chemical influences of different blending strategies on anthocyanin derivatives' formations were depending on phenolic profiles of the modifier wines and base wines, and also on the oxygen exposure. The results suggest that the chromatic improvement of base wines could be realized by blending modifier wines under different oxygen exposures. [ABSTRACT FROM AUTHOR]

• Non-enzymatic browning widely occurs in wine during and after vinification. • Mechanisms of non-enzymatic browning induced by monomeric flavan-3-ols are reviewed. • Chromatic features and contribution of various xanthylium derivatives are discussed. • Factors that influence non-enzymatic browning in wine are summarized. • Insights into the complete reaction pathways of non-enzymatic browning are still lacking. Non-enzymatic browning occurs widely in both white and red wines, and it has a huge impact on the color evolution and aging potential. Previous studies have proved that phenolic compounds, especially those with catechol groups, are the most important substrates involved in browning reactions of wine. This review focus on the current knowledge of non-enzymatic browning in wine resulting from monomeric flavan-3-ols. First, some relevant aspects of monomeric flavan-3-ols are introduced, including their structures, origins, chemical reactivities, as well as potential impacts on the organoleptic properties of wine. Second, the mechanism for non-enzymatic browning induced by monomeric flavan-3-ols is discussed, with an emphasis on the formation of yellow xanthylium derivatives, followed by their spectral properties and effects on the color change of wine. Finally, attentions are also be given to the factors that influence non-enzymatic browning, such as metal ions, light exposure, additives in winemaking, etc. [ABSTRACT FROM AUTHOR]