Studies on the Non-starchy Polysaccharides of the Endosperm of Buckwheat

Part II. The Main Polysaccharide of the Water Soluble Fraction

Abstract

Water soluble polysaccharides from the buckwheat endosperm was fractionated by salting out and a DEAE-cellulose column (phosphate form) chromatography and the main component (polysaccharide A1) was isolated as an ultracentrifugally and electrophoretically pure preparation.
The content of polysaccharide A1 in the buckwheat endosperm was 0.1_??_0.2%.
Its water solution showed high viscosity and [a]D was +39.4° The molecular weight was 240, 000-260, 000.
Polysaccharide A1 consisted of xylose, mannose, galactose and glucuronic acid. The hydrolysis of methylated polysaccharide A1 gave 2, 3, 4-tri-O-methyl-xylose, 2, 3, 4, 6-tetra-O-methyl-galactose, 2, 4, 6-tri-O-methyl-galactose, di-O-methyl-mannose and 4-O-methyl- and 5-O-methyl-glucuronic acid. These results suggested that the main chain of this poly-saccharide consisted of glucuronic acid, mannose and galactose and the former two occupied branching position with xylose and galactose residues as nonreducing end.