Exploring the Effect of Incubation pH, Temperature, and In Vitro Digestion on Antioxidant Potential of Mung Bean Protein Hydrolysates

In this study, mung bean protein hydrolysates were prepared to evaluate their antioxidant properties under simulated conditions for food processing and in vitro digestion. Mung bean protein isolate, with a protein content of 93.6%, was hydrolyzed by Alcalase at 55 °C, pH 8, for 5-7 hours, using an enzyme-to-substrate ratio of 7%. The degree of hydrolysis (DH) was monitored during enzymatic treatment, reaching selected DH values of 50% and 55% after 360 and 420 minutes, respectively. Hydrolysates collected at 360 (H360) and 420 minutes (H420) demonstrated distinct antioxidant profiles, with H360 exhibiting optimal metal chelating activity (MCA) and ABTS radical scavenging activity. The stability of antioxidant protein hydrolysates derived from mung bean protein was evaluated under different incubation pH levels (4 and 6), at different temperatures (-18°C, 4°C, and 25°C for 24 hours; 63°C for 30 minutes; and 100°C for 5 minutes) and under in vitro digestion. Antioxidant properties were influenced by incubation pH, with higher ABTS scavenging activity observed at pH 6 compared to pH 4. However, MCA did not significantly differ between the two pH levels. Additionally, hydrolysates demonstrated thermal stability, retaining significant antioxidant activity after subjected to various temperature treatment. The hydrolysates also maintained or improved antioxidant capacity post simulated gastrointestinal digestion, highlighting their potential for functional food applications.