A STUDY OF THE POLYSACCHARIDE COMPONENTS IN GLUTEN

The polysaccharide contents of glutens from 13 wheat flours were studi ed. Arabinoxylans (estimated as the sum of arabinose and xylose) repre sented similar to 0.4% by weight of the gluten. Enzymic degradation by Alcalase solubilised 90% of the gluten, but only 45% and 23% of arabi nose and xylose, respectively. These polysaccharide components were fo und mainly in the Alcalase-treated residue as cell-wall fragments. A c orrelation was found between starch and arabinoxylan content of gluten , suggesting that the amount of these components was mainly related to the water washing efficiency during the preparation of the gluten. H- 1-nmr study of the high molecular weight polysaccharide solubilised Fr om gluten by Alcalase treatment showed that wheat arabinoxylan (AX) an d arabinogalactan (AG) structural features were present, although the proportion of AG was higher than that usually found in wheal flour. A minor AX population, representing 0.1-0.2% of total AX in flour (simil ar to 8% of AX in gluten), with a highly disubstituted xylan backbone was also isolated. (C) 1997 Academic Press Limited.