The production process of tempe protein isolate from germinated soybeans and its potential as an antidiabetic

Abstract

Physical activity limitations during the COVID-19 pandemic have the potential to be a community-wide risk factor for type 2 diabetic mellitus (DM). Tempe, an indigenous Indonesian food, can be developed into protein isolate for DM treatment. The protein isolates that were used in this study were tempe protein isolate from germinated soybeans (GTPI), tempe protein isolate from non-germinated soybeans (NGTPI), and commercial soybean protein isolate (CSPI) as a control. This study aimed to evaluate the effect of the soybean germination process on the production of tempe protein isolate (TPI) and antidiabetic potency of TPI by assessing amino acid composition, aglycone isoflavone level, and in vivo hypoglycaemic assays. The results showed that the production of GTPI requires a higher extraction pH (11.6-12.6) and a lower pI (3.6-4.2) than the manufacture of NGTPI. In vivo tests showed that GTPI has a better hypoglycaemic ability than NGTPI and CSPI. The hypoglycaemic ability of GTPI is supported by the higher content of arginine and isoflavone aglycones (daidzein and genistein) in GTPI compared to NGTPI and CSPI. These findings indicated that the germination process might increase bioactive compounds in soybean, which had a strong association with tempe protein isolate's antidiabetic effectiveness.