Optimization of Production Conditions of Soy Milk GABA Produced by Probiotic Bacteria

Gamma-amino butyric acid (GABA) as a non-protein amino acid has a widespread application in the body's various organs and inhibition of many physiologic diseases. Lactic acid bacteria are able to GABA synthesis in many foods. The purpose of this study was to ferment the soymilk by a new lactic acid bacterium called Lactobacillus sp. Makhdzir Naser-1 (GQ451633). At first, optimum conditions for maximum GABA production were obtained with regard to effective factors such as inoculation time, pH, soy milk concentration and ambient temperature. The optimum conditions are: fermentation time 48 hours, pH 5.3, 12% soy milk and warming temperature 37 ° C. At optimum point, with three repeats of treatment, the produced GABA was 4.17, which has not very significant difference with the predicted value (4.188). Therefore, the accuracy of the proposed equation for predicting GABA value was confirmed.