Cereal Chem 67:434-439   |  VIEW ARTICLE

Water-Insoluble Pentosans of Wheat: Composition and Some Physical Properties.

J. Michniewicz, C. G. Biliaderis, and W. Bushuk. Copyright 1990 by the American Association of Cereal Chemists, Inc. 

Water-insoluble pentosans (WIP) were isolated from flours of seven Canadian wheat varieties belonging to several classes, and their chemical composition and physical properties were determined. Xylose and aribinose, determined by high-performance liquid chromatography, were the most abundant monosaccharides; small amounts of glucose were also present. The degree of branching (arabinose/xylose ratio) ranged between 0.96 and 0.58 whereas the ferulic acid content of various WIP preparations was 1.10- 0.86 micrograms/mg of pentosans. Comparison of the ferulic acid content between flours and the respective WIP indicated that this phenolic constituent is not uniformly distributed in wheat endosperm. Solubility of WIP in NaOH solutions increased with increasing alkali concentration; approximately 80% of WIP were solubilized in 1.0M NaOH. Oxidative gelation studies of WIP (H202/peroxidase) using small deformation oscillatory rheological testing revealed that WIP are amenable to further cross-linking via free feruloyl residues in the polymeric matrix. The farinograph water absorption of WIP-supplemented doughs depended strongly on the chemical and baking characteristics of the base flour.