THE CONSTITUTION OF THE HEMICELLULOSE OF APPLE WOOD (MALUS PUMILA L. VAR. GOLDEN TRANSPARENT)

Abstract
The hemicellulose isolated by direct alkaline extraction of the wood has been shown to be a 4-O-methylglucuronoxylan. Methylation data indicate a backbone of approximately 120 D-xylopyranose units linked by β, 1—4 bonds with single units of 4-O-methyl-D-glucuronic acid linked by α, 1—2 bonds. The proportion of acid units to xylose is approximately 1:6. Two artifacts were isolated from the hydrolysis products of the methylated polysaccharide: 4-O-(2,3-di-O-methyl-α-D-xylopyranosyl)-2,3-di-O-methyl-D-xylose and 2,3-di-O-methyl-D-lyxose.