Cereal Chem 68:145-150   |  VIEW ARTICLE

Physical Properties 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. 

The physical properties of water-soluble pentosans and their constituents, arabinoxylan and arabinogalactan, in solution or gels, were investigated using purified preparations from flours of eight wheat varieties: HY 355, HY 320, Oslo (Canada prairie spring), Glenlea (Canada utility), Fielder (Canada western soft spring), Norstar (Canada western hard red winter), Katepwa (Canada western red spring), and Marshall (a hard red spring variety unregistered in Canada). The intrinsic viscosities for arabinoxylans and arabinogalactans ranged between had ranges of 2.82-4.20 dl/g and 0.045-0.062 dl/g, respectively. Oxidative gelation of 2% (w/v) pentosan and arabinoxylan solutions (H2O2 and peroxidase) was probed by dynamic rheometry. The most rigid gel networks, as assessed by the storage modulus (G') and tan delta (G"/G'), were obtained for the preparations derived from Katepwa, followed by those from HY 355, HY 320, and Fielder. Relatively weak gels were obtained for pentosans from Oslo, Marshall, Norstar, and Glenlea. The storage modulus of arabinoxylan and pentosan gels (2%, w/v) were positively correlated with the intrinsic voscosity of the polymers (r = 0.85 and r = 0.83, respectively; P less than 0.01). Cross-linked pentosans and arabinoxylans held up to 100 g of water per gram of carbohydrate. Although both arabinoxylans and arabinogalactans reduced the surface tension of water, only arabinoxylans effectively stabilized protein foams on heating.