Cereal Chem 68:139-144   |  VIEW ARTICLE

Comparison of the Structure and Composition of Water-Soluble Pentosans from Different Wheat Varieties.

M. Izydorczyk, C. G. Biliaderis, and W. Bushuk. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Water-soluble pentosans were isolated from flours of eight wheat varieties belonging to several Canadian classes. The pentosans were fractionated by (NH4)2SO4 precipitation into arabinoxylans and arabinogalactans. The arabinoxylan from flours of Canada western red spring and Canada prairie spring had the lowest degree of branching, and that from the Canada utility class the highest. Among varieties, the degree of branching of the arabinogalactans was relatively constant, except for the Canada western red spring variety Katepwa, which was substantially lower. The peptide moieties of the arabinogalactans contained high levels of alanine and hydroxyproline. Cis- and trans-isomers of ferulic acid were found in the arabinoxylans. The ferulic acid content of arabinoxylans from different varieties varied significantly; the highest amount was found in the arabinoxylan of the Canada western soft spring variety Fielder. Purified arabinoxylans showed intervarietal differences in the molecular weight distribution by Sepharose CL-4B chromatography; the arabinoxylan from Katepwa had the highest apparent molecular weight. In contrast, the arabinogalactan-peptide fractions had similar molelcular weights as determined by Sephacryl S-300 gel filtration.