Production of γ-amino butyric acid by lactic acid bacteria in soybean broth

Abstract

We examined the effective utilization of food waste soybean broth. Lactic acid bacteria added to the soybean broth were shown to produce γ-amino butyric acid (GABA). Lactic acid bacteria inoculants from the 1 500 stock strains maintained in our laboratory were tested for efficient production of GABA. Addition of the lactic acid bacteria that efficiently produced GABA to the soybean broth resulted in the production of 3.5 mM (36 mg/100 ml) GABA. In addition, high levels of GABA (46-79 mg/100 ml) were produced by adding glutamic acid to the soybean broth at 0.05-0.1% (w/v). In functional tests, soybean broth was shown to have high ACE inhibitory activity and DPPH radical scavenging ability, and also to have functionality of α-glucosidase inhibition activity and α-amylase inhibition activity. By experimenting with making bread with the addition of a lactic acid fermentation liquid that includes GABA, we tried to utilize this material as a food ingredient.