Effect of extruded adzuki bean flour on the quality and α-glucosidase inhibitory activity of Chinese steamed bread.

In order to improve the commercial and nutritional quality of Chinese steamed bread (CSB), effect of extruded adzuki bean flour (EABF) substitution (10%, 20%, 30%, and 40%) for wheat flour on the quality properties of blended flour and CSB was studied. Results showed that the development time, stability time, and farinograph quality number of blended flours were decreased with EABF addition, although water absorption and softening degree were increased. Pasting properties of them were also degraded with the addition. EABF substitution lowered the lightness and strengthened the hardness of CSB. The sensory evaluation total scores of CSB were both improved with 10% and 20% EABF addition, because slight red color of them was favored by the panelist. Nutritional analysis showed that CSB with 10% and 20% EABF ranked higher protein and essential amino acids content than that of WF-CSB, especially lysine and threonine. Addition of EABF contributed to the superior α-glucosidase inhibitory activity of protein isolated from CSBs. α-Glucosidase inhibition rate of CSB made from EABF (39.88%) was improved nearly five times compared with that of WF. It might be concluded that CSB with addition of 10% and 20% EABF could be used as a nutritional and healthy staple food.