PT - JOURNAL ARTICLE AU - Stéphane Vidal AU - Thierry Doco AU - Michel Moutounet AU - Patrice Pellerin TI - Soluble Polysaccharide Content at Initial Time of Experimental Must Preparation AID - 10.5344/ajev.2000.51.2.115 DP - 2000 Jan 01 TA - American Journal of Enology and Viticulture PG - 115--121 VI - 51 IP - 2 4099 - http://www.ajevonline.org/content/51/2/115.short 4100 - http://www.ajevonline.org/content/51/2/115.full SO - Am J Enol Vitic.2000 Jan 01; 51 AB - The diversity of procedures used for the analysis of polysaccharides in musts obtained at laboratory scale did not allow their accurate quantification and characterization. Soluble polysaccharides have been isolated from musts at the initial time of preparation of Sauvignon blanc and Ugni blanc cultivars and the influence of the mode of preparation has been investigated. Heat treatment, commonly used for the inactivation of endogenous glycosylhydrolases, led to an overestimation of polysaccharide contents. Consequently, the characterization of must polysaccharides requires their isolation from crushed and pressed grapes, a procedure representative of the typical process used for white winemaking. Glycosyl residue, determined by GC of their per-Otrimethylsilylated methyl glycosides, and glycosyl linkage, determined by GC of their partially methylated and carboxyl-reduced alditol acetates, composition analyses showed that polysaccharides were a complex mixture of pectic (galacturonans, type I and II arabinogalactans, arabinans), cellulosic and hemicellulosic (xyloglucans and mannans) polysaccharides. Type II arabinogalactan proteins, which are soluble proteoglycans, are the most abundant polysaccharides, whereas the others, that are structural components of cell walls, are present in lower amounts. The significant difference concerning the polysaccharide composition of musts and wines is discussed. Furthermore total polysaccharides were separated in calcium- and ethanol-precipitated polysaccharides. Their respective glycosyl-composition analyses, determined by GC of their per-O-trimethylsilylated methyl glycosides, revealed that neutral "gums" and acidic "pectins" could not be separated by specific precipitation.