NATURAL VARIATIONS IN THE CONTENTS OF STRUCTURAL ELEMENTS OF WATER-EXTRACTABLE NONSTARCH POLYSACCHARIDES IN WHITE FLOUR

Selected samples (n = 20) of white flour, with a high level of variation in chemical composition and properties, were analysed for their contents of phenolic acids and differently-linked arabinose, xylose and galactose residues present in water-extractable non-starch polysaccharides. The arabinoxylan fractions isolated had a high variation in content [range 0·36-0·78% (w/w) of dry matter] and structure. Three different structural features of (1 → 4)-linked β-d-xylose residues, i.e. un-, mono- or di-substituted with terminal α-l-arabinosyl units, were determined quantitatively. On average, 65% of the xylose residues were unsubstituted. No significant correlation was found between the contents of mono- and di-substituted xylose residues, but the relative portions of these residues were correlated negatively. Arabinogalactans were also present in the fractions isolated and had a high variation in content and structure. © 1994 Academic Press. All rights reserved.