Functional alteration of glucose-conjugated adzuki bean protein

Abstract

This study aimed to investigate whether adzuki bean protein could be functionally modified through glycation, similar to soybean 11S globulin, using the Maillard reaction. Optimal preparation conditions, identified via random-centroid optimization, indicated that maximum hydroxyl radical antioxidant activity was achieved at a temperature of 59 °C, relative humidity of 57 %, reaction time of 35.8 h, and glucose-to-adzuki bean protein ratio of 10.51:1 (w/w). SDS-PAGE analysis revealed that glucose-conjugated adzuki bean protein exhibited glycation, with an increase in molecular weight after 8 h. The hydroxyl radical antioxidant capacity of optimally glycated adzuki protein was determined to be 78.61 ± 49.3 µmol of gallic acid equivalent/g of protein. This antioxidant capacity was improved compared to the native adzuki protein, and was equivalent to that of glycated soybean 11S globulin. These results suggest that functional alteration of adzuki bean protein can be achieved to the same extent as that of soybean protein.