Wine polysaccharides

A sensory study based on an incomplete factorial design allowed to demonstrate that astringency of procyanidins was reduced in the presence of rhamnogalaturonan II added at levels encountered in wine but was modified neither by anthocyanins nor by the other wine polysaccharides (mannoproteins and arabinogalactan proteins). Increase in ethanol level resulted in higher bitterness perception but had no effect on astringency. 

Riou, V. et ak. Aggregation of grape seed tannins in model — effect of wine polysaccharides. Food Hydrocoil 16, 17, 2002. 

Dols-Lafalgue, M., Gindreau, E., Le Marrec, C., Chambat, G., Heyraud, A., Lonvaud-Funel, A. (2007). Changes in red wine polysaccharide composition induced by malolactic fermentation. J. Agric. Food Chem., 55, 9592-9599. 

Waters, E.J. (1991). Heat unstable wine proteins and their interactions with wine polysaccharides. PhD thesis. University of Adelaide, Australia. 

AGPs have been found to represent more than 40% of total red wine polysaccharides. They are mainly constituted by glycosidic residues of arabinose, galactose and glucuronic acid although other monosaccharides such as rhamnose, glucose... 

Carbohydrates are minor components of wine which contribute to sensorial properties and play and important role in the different reactions occurring during fermentation and aging. Whereas monosaccharides and polyalcohols are rather well-known, more research is necessary on disaccharides, oligosaccharides and non-phenolic glycosides. The presence of cyclitols in wines and wine derivatives can constitute a useful tool to characterize their origin. Among all the studies related to carbohydrates in wine, polysaccharides have been the most important focus in the last years. 

Boulet, J.C., Williams, P., Doco, T. (2001). A Fourier transform infrared spectroscopy study of wine polysaccharide. Carbohydr. Polym., 69, 79-85. 

Coimbra, M.A., Goncalves, F., Banos, A., DelgadUlo, 1. (2002). FT-IR spectroscopy and chemo-metric analysis of white wine polysaccharide extracts. J. Agric. Eood Chem., 50, 3405-3411. 

Wine polysaccharides, ranging from 500 to 1500 mg/L (Will and Dietrich 1990), mainly come from grape primary cell walls, and from autolysis of micro-organisms... 

Dufour and Bayonove (1999a) reported two criteria for polysaccharide discrimination acidity and protein content. Neutral peptic substances (type II arabinogalac-tans and arabinogalactans-proteins) represent 40% of the polysaccharides in wine and acidic pectic polysaccharides, (e.g. homogalacturonans and rhamnogalacturo-nans) account for 20% of them. Because of the difficulty in purifying wine polysaccharides, most of the studies on interactions between wine polysaccharides and aroma compounds have been carried out with exocellular and cell wall mannoproteins (thus mainly glycoproteins) of Saccharomyces (see effect of yeast and derivatives in the next section). 

Among wine polysaccharides, mannoproteins play an important role in protein haze stabilisation (Waters et al. 1994 Dupin et al. 2000). Gelatin fining of a wine phenolic extract in wine-like solution resulted in a much higher precipitation rate than when the same treatment was applied on the original wine. After addition of wine polysaccharides at the concentration normally encountered in wines, precipitation was reduced back to the level measured in wine, confirming the stabilizing effect of polysaccharides (Cheynier et al. 2006). 

Gerbaud, V, Gabas, N. (1997). Influence of wine polysaccharides and polyphenols on the crystallization of potassium hydrogen tartrate. J. Int. Sci. Vigne Vin, 31,65-83. 

Vernhet, A., Moutounet, M. (2002). Fouling of organic microfiltration membranes by wine constituents importance, relative impact of wine polysaccharides and polyphenols and incidence of membrane properties./. Membrane Sci., 201, 101-122. 

Recently, Carvalho et al. (2006b) studied the influence of wine polysaccharides (AGP, RGll and MP) on salivary protein-tannin interactions. The results showed that the most acidic fractions of AGPs and MPs have the ability to inhibit the formation of aggregates between condensed tannins and two different salivary proteins (a-amylase and lB8c). The concentrations tested are below to those present in wine which means that they could have an influence in wine astringency. 

Vernhet, A., Pellerin, R, Prieur, C., Osmianski, J., Moutounet, M. (1996). Charge properties of some grape and wine polysaccharide and polyphenolic fractions. Am. J. Enol. Vitic., 47, 25-30. 

Boulet, J.C., Doco, T, Roger, J.M. (2007b). Improvement of calibration models using two successive orthogonal projection methods. Application to quantification of wine polysaccharides, Chemometr. Intell. Lab., 87, 295-302. 

Vemhet A, Pellerin MP, Belleville J, Planque J, and Moutounet M. Relative impact of major wine polysaccharides on the performances of an organic microfiltration membrane. Am. J. Enol. Vitic. 1999 50(l) 51-56. 

At present in enology, two particular cases are analyzed in this manner strains of Pediococcus damnosus, responsible for ropiness disease, and strains which produce histamine, notably 0. oeni. Preliminary studies have shown that P. damnosus strains capable of synthesizing the ropy wine polysaccharide possess a supplementary plasmid, contrary to normal strains. The ropy character is linked to the presence of this plasmid. A fragment was cloned in E. coli and now constitutes the base material for preparing the probe. In this manner, colony hybridization permits the identification of ropy clones even when mixed with other Pediococcus clones or other species of bacteria. This method is routinely used to identify this undesirable population in the microflora of wines at the end of winemaking and during aging (Lonvaud-Funel et al, 1993). 

MA Coimbra, F Goncalves, AS Barros, I Delgadillo. Fourier transform infrared spectroscopy and chemometric analysis of white wine polysaccharide extracts. J Agric Food Chem 50 3405-3411, 2002. 

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