Effect of buckwheat hull particle-size on bread staling quality

The mechanical grinding scale of insoluble dietary fiber has an important influence on bread staling quality. We investigated the effects of buckwheat hull (BWH) powder at tissue-scale (500–100 μm) and cell-scale (50–10 μm) on the physical and structural changes of bread during storage. The addition of tissue-scale BWH had little effect on loaf volume and crumb firmness of bread, while that of cell-scale BWH significantly decreased specific volume and baking loss, and resulted in higher bread firmness, compared with the control (100 % wheat bread). The effect of cell-scale BWH on delaying amylopectin retrogradation and starch recrystallization during bread storage was superior to that of tissue-scale BWH. Tissue-scale BWH made the gas cell structure of the crumb coarse and open, promoting the evaporation of water during storage. BWH at the cell-scale had a stronger water-binding ability than tissue-scale BWH, which restricted the loss of water, inhibiting bread staling.