Exploring the profile of amino acids and ethnography study in the biodiversity of tempeh as fermented foods of Indonesia

Abstract Tempeh is known worldwide as a functional food with several health benefits, such as ACE inhibitory, hypotensive, and antioxidative. Although soybeans contained opioids, peptides that affect mental state, there was no report on the potential of tempeh as a source of peptides with affective or cognitive function. This study examined ethnography of tempeh and its functionality of amino acids. Amino acids profile was examined to reveal their possible role in improving depression, as indicate by the concentration of tryptophan (Trp) and its ratio to large neutral amino acids (LNAA). Fresh tempeh types of different raw materials (soybean, okara, velvet bean, lablab bean, and fresh coconut press cake) were collected from production areas. Samples were run for high-performance liquid chromatography. Results showed that protein and amino acid concentrations in tempeh ranged, respectively, from 13.97 and 8% (gembus tempeh) and 45.5 and 18% (Malang tempeh). The amino acid score in all tempeh met the WHO standard for nine essential amino acids, indicating good quality of amino acids. Tempeh made from peanut press cake showed all amino acids scored higher than 100, while gembus tempeh showed three amino acids with a score of less than 100. Methionine was the limiting amino acid, while glutamate was the predominant amino acid of tempeh. However, in koro, gembus, or dage tempeh, tryptophan in tempeh samples showed the ability to serve as an antidepressant activity. The concentration of tryptophan in koro, gembus, or dage tempeh, showed the possibility to give antidepressant activity. This work revealed nutritional and functional health benefits related to the amino acid profile of different types of tempeh available in Indonesian markets. Different types of tempeh and prolonged fermentation affected the amino acid profile and protein concentration of tempeh. Overcoming challenges related to taste, texture, and cultural acceptance, as well as addressing sustainability issues in soybean farming, will be essential to the long-term success and growth of tempeh in the global food industry.