Structure of a hemicellulose B fraction in dietary fiber from the seed of grape variety Palomino (Vitis vinifera cv. palomino).

ABSTRACT

The structure of one of the hemicellulose B fractions (HB-1) extracted from the seeds of the grape variety Palomino (Vitis vinifera cv. Palomino) has been studied by means of methylation analysis, 1H NMR, 13C NMR, and partial acid hydrolysis. This hemicellulose seems to be a homogeneous polysaccharide with an apparent molecular weight of 35 000. Its structure is that of an acidic arabinoxylan, a linear chain of beta-D-xylopyranosyl units, bonded together by (1-->4) glycosidic links, containing a single L-arabinofuranosyl, alpha-D-xylopyranosyl and 4-O-methyl-alpha-D-glucopyranuronosyl residues joined by glycosidic links to position 2 of the xylose units of the main chain, in proportions of one branch to every seven units of xylose.