Functional properties of tempe protein isolates derived from germinated and non-germinated soybeans

Abstract

Tempe is an indigenous Indonesian soybean fermented food. Tempe is a source of protein which can be used as a raw material for making protein isolate. In this study, the tempe was produced from Grobogan local soybeans with two types of treatment, germinated and non-germinated. The two types of tempe produced were then processed into protein isolates, namely tempe protein isolate from non-germinated soybeans (NGTI) and tempe protein isolate from germinated soybeans (GTI). This research aimed to measure the functional properties of NGTI and GTI and then compared them to CSI (commercial soy protein isolate). The results of this study showed that the functional properties of GTI and NGTI were not significantly different. Still, GTI had significantly higher values (p < 0.05) than CSI on the parameters of water absorption capacity (5.86 and 1.57 g water/g sample), oil absorption capacity (2.48 and 1.19 mL oil/g sample), foam capacity (133.50 and 120.00%), foam stability, emulsion stability, and gel strength. From this study, it can be concluded that GTI and NGTI have good functional properties that have an opportunity to be applied in the food industries as a substitute for CSI.