Comparison of dextran molecular weight on wheat bread quality and their performance in dough rheology and starch retrogradation

The aim of this study was to compare effects of linear dextrans (backbones of alpha-(1 -> 6) linkages) varying with weight-average molecular weights (Mw: T10, T70, T250, T750, T2000) on the quality of wheat breads. The firmness of fresh bread crumb was decreased with increasing dextran Mw and the highest Mw dextran (T2000) lowered the staling rate of stored breads. Dough rheology clarified that only the specific dextran (T70) apparently changed dough viscoelastic, strengthening the viscous behavior. Significant decreases in breakdown and setback viscosity of starch slurry were observed by addition of dextrans, especially dextran T2000. Analyses in the long-term retrogradation of starch and starch-gluten systems indicated that the promising antistaling influence of dextran T2000 was caused by either inhibitions of amylopectin retrogradation or beneficial variations induced by gluten. Positive effects of starch-gluten and dextran-gluten associations on amylopectin retrogradation were revealed. These results suggested that the highest Mw dextran (T2000) possessed the potential for increasing consumer acceptance of bread products.