Effects of dextran with different molecular weights on the quality of wheat sourdough breads

This research aimed at investigating the effects of different weight-average molecular weights (M-w: T10, T70, T250, T750, T2000) of dextran (alpha-(1 -> 6)-linked linear backbone, alpha-(1 -> 3)-linked branching) on wheat sourdough bread qualities. Texture analyzer showed that dextran contributed to a significant inhibition of bread staling, particularly dextran T2000. Pasting profiles (Rapid visco-analysis) and steady rheological properties (steady shear measurements) of samples indicated that dextran T2000 suppressed the swelling and gelatinization of wheat starch granules and bound a great amount of water, thus retarding the aging process. Dextran T2000 markedly improved the elastic properties of sourdough-containing dough. Wheat sourdough breads containing dextran T10 exhibited unexpected less firm crumb structure. The improvement of bread qualities was a function of the M-w of dextran. Dextran with high Mw values has the potential for improving the quality of wheat sourdough breads, especially extending shelf life.