Cell-wall polysaccharides of rye-derived wheats: Investigations of the biochemical causes of dough stickiness

Abstract

Rye contains much higher levels of cell-wall polysaccharides such as pentosans and (1 → 3),(1 → 4)-β-glucans than wheat, suggesting that these polysaccharides might contribute to the undesirable dough stickiness found in many rye-derived wheats such as those with the IB/IR chromosome translocation. The pentosan and β-glucan content of whole grain and endosperm samples was determined for two varieties of wheat, two of rye and three rye-derived wheats. The pentosan and β-glucan contents of normal and rye-derived wheat were similar. Slightly higher β-glucan levels were detected in the endosperm of the rye-derived wheat samples exhibiting dough stickiness so this character was examined further. Flour produced in a laboratory mill from 18 wheat samples, including 12 rye-derived wheat lines, contained 1·04–2·39% pentosan and 0·14–0·28% β-glucan but the content of these polysaccharides did not show a clear association with the level of dough stickiness. Examination of flour of three varieties of normal wheat grown at each of nine locations showed that there were significant differences in the pentosan and β-glucan content of different varieties of wheat and in the wheat from different sites. The non-starch polysaccharide levels in the flour from rye-derived wheats were within the range found in normal wheats.