Effect of winemaking techniques on polysaccharide composition of Cabernet Sauvignon, Syrah and Monastrell red wines

Background and Aims: Several authors have demonstrated the interesting properties of wine polysaccharides. These compounds act as protective colloids and are able to interact with tannins and anthocyanins in wines, reducing their reactivity and increasing colour stability. Little, however, is known about the release of polysaccharides by winemaking technologies. We examine the effect of several winemaking techniques - cold prefermentative maceration, dry ice addition and grape skin freezing, and addition of two maceration enzymes - on the quantity and composition of polysaccharides extracted from the three red wine cultivars - Cabernet Sauvignon, Syrah and Monastrell. Methods and Results: The molecular mass distribution and composition of polysaccharides were determined, respectively, by high-performance size-exclusion chromatography and by gas chromatography. The amount of some polysaccharide fractions extracted depended on the grape cultivar. The addition of commercial pectic enzyme preparations released a greater quantity of polysaccharides in all three cultivars studied and altered the polysaccharide composition of the Cabernet Sauvignon wine. The effect of the other treatments on the amount of polysaccharides depended on the cultivar. Conclusion: This study confirms that grape cultivar and winemaking technique have a significant impact on the quantity and composition of polysaccharides extracted from grapes into wine. The concentration of polysaccharides rich in arabinose and galactose, and in rhamnogalacturonan II was greater in the Syrah wine than that in the Cabernet Sauvignon and Monastrell wines. Both enzymatic treatments and also dry ice addition had a significant influence on the polysaccharide concentration and composition of the wines made from a given cultivar, whereas cold prefermentative maceration or grape skin freezing had no effect. Significance of the Study: This is the first report that shows that the polysaccharide composition of Cabernet Sauvignon, Syrah and Monastrell wines is affected by winemaking technique

Effect of enzyme additions on the oligosaccharide composition of Monastrell red wines from four different wine-growing origins in Spain

Food Chem.ISI Document Delivery No.: AE6WITimes Cited: 0Cited Reference Count: 38Apolinar-Valiente, Rafael Williams, Pascale Mazerolles, Gerard Romero-Cascales, Inmaculada Gomez-Plaza, Encarna Maria Lopez-Roca, Jose Maria Ros-Garcia, Jose Doco, ThierryMinisterio de Ciencia e Innovacion of Spain [AGL2006-11019-C02-01/ALI]; Government of SpainThis work was made possible by financial assistance of the Ministerio de Ciencia e Innovacion of Spain, Project AGL2006-11019-C02-01/ALI. Author R. Apolinar-Valiente is the holder of a FPI fellowship from the Government of Spain.Elsevier sci ltdOxfordThe release of oligosaccharides during winemaking depends on the grape skin cell wall degradation, which can be facilitated by the use of enzymes. Oligosaccharide quantities and composition in wine could be influenced by the "terroir" effect. Monastrell wine was elaborated from grapes from four different "terroirs" (Canada Judio, Albatana, Chaparral-Bullas and Montealegre). Monastrell wines were also treated with beta-galactosidase enzyme addition and commercial enzyme addition. The results showed significant differences in the Monastrell wine oligosaccharide fractions, according to the geographical origin of grapes. A higher quantity of oligosaccharides was found for three out of four terroirs studied when commercial enzymes were added. The use of commercial enzyme modified the Arabinose/Galactose and the Rhamnose/Galacturonic acid ratios in Canada Judio and Albatana terroirs wines, and it modified the (Arabinose + Galactose)/Rhamnose ratio in Canada Judio, Albatana and Chaparral-Bullas terroirs wines. Therefore, the "terroir" impacts the effect of commercial enzyme treatment on wine oligosaccharide composition

Complex pectin metabolism by gut bacteria reveals novel catalytic functions

The metabolism of carbohydrate polymers drives microbial diversity in the human gut microbiota. It is unclear, however, whether bacterial consortia or single organisms are required to depolymerize highly complex glycans. Here we show that the gut bacterium Bacteroides thetaiotaomicron uses the most structurally complex glycan known: The plant pectic polysaccharide rhamnogalacturonan-II, cleaving all but 1 of its 21 distinct glycosidic linkages. The deconstruction of rhamnogalacturonan-II side chains and backbone are coordinated to overcome steric constraints, and the degradation involves previously undiscovered enzyme families and catalytic activities. The degradation system informs revision of the current structural model of rhamnogalacturonan-II and highlights how individual gut bacteria orchestrate manifold enzymes to metabolize the most challenging glycan in the human diet