Enzymatic hydrolysis by Alcalase of red bean protein to develop corn starch/red bean protein hydrolysate complex for reduced glycemic response in vitro

BACKGROUND Legume protein hydrolysates have garnered significant attention because of their multifunctional properties and potential applications in agriculture, food, and health sectors. In this study, red bean protein (RP) was extracted and subjected to Alcalase hydrolysis to obtain red bean protein hydrolysate (RPH). Subsequently, the protein hydrolysate was incorporated into corn starch (CS) to prepare corn starch/red bean protein hydrolysate complex (CS‐RPH), aiming to control the sugar release during gastrointestinal digestion of native starch. RESULTS RPH showed higher ABTS free radical scavenging activity, whereas FRAP activity experienced a significant drop compared to crude protein. In addition, foaming ability of RPH was remarkably improved and the protein fractions were shown to have molecular weight in the range of 15–20 kDa, in reference to 50–70 kDa of crude counterparts, as illustrated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Furthermore, RPH exhibited little cytotoxicity at a dose below 2000 μg mL −1 , despite minimal anti‐inflammatory efficacy against pro‐inflammatory cytokines nitric oxide and interleukin‐6. For the development of CS‐RPH, 2% RPH was added to 10% gelatinized CS and further subjected to in vitro gastrointestinal digestion for evaluating the sugar release. The results showed that RPH reduced 4.82% sugar release of CS, highlighting its potential in health‐related application. CONCLUSION Alcalase hydrolysis successfully converted red bean protein into bioactive hydrolysates with improved functional properties. Incorporation of red bean protein hydrolysate into corn starch effectively reduced sugar release during simulated gastrointestinal digestion, demonstrating its potential as a functional ingredient for developing low‐glycemic foods and managing postprandial glucose response.