Application of ultrasound in germinated soybean tempe protein concentrate production with various types of solvents

Abstract

Tempe is a traditional Indonesian fermented food that has high protein content. It has been known as a source of bioactive compounds, such as peptides and isoflavones, which contribute to immune health. Therefore, tempe has the potential to be processed into raw materials for food and supplement products, such as protein concentrate. In this study, the tempe was made using germinated and non-germinated soybeans. Tempe protein concentrate production process was carried out by removing the fat in tempe flour by conventional and ultrasound-assisted extraction methods using two types of solvents: ethanol and hexane. This research aimed to compare the physicochemical characteristics of the protein and concentrates on obtaining the optimum treatment with the highest protein content. The results showed that ultrasound-assisted extraction using hexane significantly improved fat extraction, resulting in protein concentrate with higher protein content. Germinated soybean tempe protein concentrate extracted using hexane had the best protein concentrate, which consisted of the highest protein content (72.8%), brightness value (L*) 84.3, whiteness index 81.3, bulk density 0.5 g/mL, and angle of repose of 29.4o. The germination process in soybean improved the protein content of the concentrate as the result of other components’ degradation into energy required for new protein synthesis.