Cereal arabinoxylans: advances in structure and physicochemical properties

Abstract

Arabinoxylans constitute a major fraction of cereal cell wall polysaccharides. They consist of a linear β-(1 → 4) linked xylan backbone to which α-l-arabinofuranose units are attached as side residues via α-(1 → 3) and/or α-(1 → 2) linkages. Several structural models have been put forward based on enzymic degradation studies and structure elucidation of oligosaccharides by NMR, methylation, and periodate oxidation techniques. These tentative models present different substitution patterns of arabinoses along the xylan chain. Cereal arabinoxylans exhibit a great deal of structural heterogeneity with respect to ratio of Araf Xylp, substitution pattern of arabinoses, content of feruloyl groups and molecular size. The conformation and physicochemical properties (viscosity, gelation potential, intermolecular association) of arabinoxylans in aqueous solutions are dependent on the molecular features of these polysaccharides; specific structure-property relationships have been established in model and actual food systems. Wheat and rye arabinoxylans are important functional ingredients in baked products affecting the mechanical properties of dough, as well as the texture and other end-product quality characteristics. © 1995.