Influence of high amylose corn starch addition on the changes of bread quality during storage

To investigate the effect of high-amylose corn starch (HACS) on bread quality during storage, HACS with 65.85% amylose content and wheat flour were used as materials. The wheat flour was partially replaced by 10%、20%、30%、 40% HACS, and bread was produced using the direct fermentation method. The bread was then stored at low temperature (4 ℃), 50% relative humidity for 10 days. The texture properties, water migration, and crystal structure changes of the bread were determined using a texture analyzer, low-field nuclear magnetic resonance (NMR), and X-ray diffraction, respectively. Additionally, the changes of resistant starch in bread were determined by in vitro simulated digestion method. The results indicated that the addition of HACS increased the content of resistant starch in bread and decreased the in vitro digestibility of starch. Texture characteristics showed that the addition of HACS had a certain negative effect on hardness, and the addition of HACS increased the hardness of bread. The hardness of bread with adding 10% and 20% of HACS increased to 1.73 and 2.70 folds, respectively, as that of the control bread. The springiness decreased with the increase of HACS. With the increase of storage time, the moisture content of bread gradually decreased. The hardness and chewiness of the bread were increased, while the springiness and resilience of the bread were decreased. After 10 days of storage, the increase rate of hardness and relative crystallinity of HACS bread was slower than that of the control group without HACS. Bread with 40% HACS addition exhibited a 19.60% reduction in bound water A₂₁, a 0.96% increase in immobilized water A₂₂, and a 40.62% increase in free water A₂₃. The addition of HACS significantly increased the resistant starch content in the bread. In conclusion, HACS can improve the textural properties of bread during storage to a certain extent. The findings provide a reference for the improvement of the quality of HACS bread.