Evaluation of hypoglycaemic potency in tempe with soybean germination process and extended fermentation time

Abstract

One of the potential hypoglycaemic food from Indonesia is tempe. The use of germinated soybean and the extended fermentation time are potential methods to increase hypoglycaemic activity. In this study, the potential hypoglycaemic activity of tempe due to the use of germinated soybeans as raw material and the extended fermentation time (observation of 48, 72, and 96 hrs) was evaluated. The observations included insulinotropic free amino acids, soluble protein, peptides profile, antioxidants capacity, isoflavones, total phenolic compounds, and the α-glucosidase inhibitor activity. During the extended fermentation time from 48 hrs to 96 hrs, the germinated soy tempe had the highest insulinotropic free amino acids level, while non-germinated soy tempe had the highest antioxidant components (isoflavones, total phenolic compounds, and antioxidants capacity). However, the activity of α-glucosidase inhibitor due to treatments was decreased, suspiciously related to the decrease of the 11.40 kDa peptide, which was dominant in this study. This study showed that the extended fermentation time from 48 to 96 hrs and the use of germinated soybean was able to increase the tempe hypoglycaemic potencies based on the insulinotropic free amino acids and antioxidant component, but not for α-glucosidase activity.