STRUCTURAL CHARACTERISTICS OF THE COLD-WATER-SOLUBLE ARABINOXYLANS FROM THE WHITE FLOUR OF THE SOFT WHEAT VARIETY KADET

Cold-water-soluble arabinoxylan polymers from the soft wheat variety Kadet were isolated by a stepwise (NH4) 2SO4 precipitation and freed from co-precipitating proteins by pronase digestion. The purified arabinoxylans, representing 0.5% of the dry weight of the white flour, were fractionated by graded precipitation with ethanol. Monosaccharide analysis revealed the major carbohydrate fractions to contain arabinoxylans only. The arabinoxylans are heterogeneous in molecular size. Determination of the carbohydrate composition in conjunction with methylation analysis and C-13-NMR spectroscopy, indicated that they can be divided into specific groups, based on characteristic differences with respect to D-xylopyranose to L-arabinofuranose ratio and in 2,3,4-tri-:3,4-di:4-mono-substituted D-xylopyranose ratio.