Nutritional aspects and amino acid profiles of tempe from local, imported, and black soybean relating to the functional properties

Abstract

Soybean (Glycine max L) is a legume rich in protein, fat, vitamins, minerals and fibre. The nutritional value of soybeans and the amino acid profiles of the processed fermented soybean (Tempe) products need to be studied. Soybean and Tempe flour from black soybean, local soybean (Anjasmoro variety) and imported soybean (USA soybean) were analyzed proximately, including carbohydrates (spectrophotometric method), protein (Kjeldahl method), fat (Soxletation method), fiber (gravimetric method), and water content (gravimetric method). The amino acid profile of Tempe flour was measured by UPLC and LC/MS/MS methods. Local soybeans had the highest protein content (45.19%), followed by black and imported soybeans (36.87% and 35.95%, respectively). The protein content of local soybean Tempe flour was the highest (45.83%) compared to other soybean Tempe flour. The fiber content of local and black soybean Tempe flour (14.79% and 13.81%, respectively) was higher than that of imported Tempe. Amino acid profiles test of black soybean Tempe flour, local soybean, and imported soybean showed that the amino acids L-Glutamic Acid, L-Arginine, L-Leucine, and L-Aspartic Acid had the highest amounts compared to other amino acids, ranging from 30-75 thousand ppm. This shows that various soybeans affect the amino acid composition of the soybean protein. The amino acid content of Tempe from local soybeans is higher than the amino acid content of tempe from black and imported soybeans. This may influence the amino acids or peptides’ functional properties, such as antihypertensive and antimicrobial properties. Continuous research in vitro and in vivo should be conducted to explore the functional properties of Tempe flour from local soybean.