A study of pectic polysaccharides in musts from various mature grapes grown in the Pech Rouge experimental vineyards.
Soluble pectic polysaccharides were isolated from musts of seven mature grape cultivars by a 4-step procedure: pressing of the berries, denaturation of soluble proteins from must by emulsification with chloroform, elimination of diffusable molecules by extensive dialysis and finally discoloration onto Polyamide CC6. The polysaccharides were mainly constituted of arabinose, galactose and galacturonic acid, and their concentration in musts varied from 133 to 593 mg/l. The arabinose/galactose molar ratio was stable (0.91-1.04) for all cultivars, but one, Cinsaut (0.68). Methylation analyses showed that the polysaccharides from musts are a complex mixture of type II arabinogalactans, arabinans and rhamnogalacturonans. Similarities were observed in the relative distributions of galactose and arabinose structural features except for the Cinsaut and Grenache cultivars in which higher proportions of 3- and 3,6-linked galactose were found.
D002241:Carbohydrates / Q000032:analysis; D002849:Chromatography, Gas; D005602:France; D005638:Fruit / Q000032:analysis*; D008745:Methylation; D008968:Molecular Conformation; D010368:Pectins / Q000032:analysis*; D011134:Polysaccharides / Q000032:analysis* / Q000302:isolation & purification
D002241:Carbohydrates; D011134:Polysaccharides; D010368:Pectins