Isolation and Chemical Characterisation of Wheat Arabinoxylans
Department of Biology, Faculty of Natural Sciences, St. Cyril and Methodius University, Trnava, Slovakia
Keywords: arabinoxylans, isolation, wheat, non-starch polysaccharides
The main building components of arabinoxylans (AX) are ?-L-arabinose and ß-D-xylose, but their structure varies largely with cultivar source and tissue. Cereal grains are the best known and most studied source of AX. Traditionally, AX are classified into water-extractable (WE AX) and non-extractable AX (WN-AX). WN-AX are fixed in the cell wall by non-covalent and covalent bonds with other AX molecules or with other cell wall constituents. In contrast, WE-AX are loosely bonded to the cell wall by crosslinking with other components. A part of the AX from wheat flour, wheat bran can be extracted with water, yielding a WE-AX-containing fraction. Treatment of the water-non-extractable residue with Ba(OH)2 solutions or with an alkaline solution of H2O2 partly solubilizes WN-AX, yielding an alkali-solubilized AX-rich fraction.
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