A hemicellulose B fraction from grape skin (Vitis vinifera, palomino variety)

The structure of a hemicellulose B fraction (B-1) isolated from grape skins (Vitis vinifera) of the Palomino variety has been studied by methylation a nalysis, H-1 NMR and C-13 NMR spectroscopy, and partial acid hydrolysis. He micellulose B-1 appeared to be homogeneous by gel filtration with a weight- average molecular weight of 22 600. This polysaccharide is a linear xyloglu can chain composed of xylopyranosyl and glucopyranosyl residues linked by b eta-(1 -->4) glycosidic bonds. Attached to this backbone, 4-0-methyl-D-gluc uronopyranosyl acid, D-glucopyranosyl, and L-fucopyranosyl residues occur a t position 2 in a ratio of one residue for every five units of xylose in th e main chain, with D-xylopyranosyl residues attached at position 6 of gluco se units in a ratio of one residue for every two glucose-derived moieties i n the main chain.