Abstract
Rice flour can be substituted with powder from such starch-rich vegetables, as potatoes, sweet potatoes, taros and yams when making rice bread. We examined in this study, the effect of on staling of rice bread when substituting rice flour with potato powder. There was no difference in the specific loaf volume of bread with sweet potato, taro and yam powder substituting for rice flour and the control bread (100% rice flour). However, the specific loaf volume when substituting with potato powder was significantly decreased with increasing substitution ratio. The crumb hardness 3 days after baking was significantly lower than the control when substituting with sweet potato powder. Thermostable β-amylase included in sweet potato powder, produced a large amount of maltose by starch degradation during bread baking. Significant maltose was also detected in the crumb of rice bread substituted with sweet potato powder. We infer from these results, that maltose produced by β-amylase in sweet potato powder inhibited the recrystallization of starch, and prevented staling of the rice bread.
