A method for production of γ-amino butyric acid (GABA) using barley bran supplemented with glutamate

γ-amino butyric acid (GABA) has antihypertensive and anti-stress effects on human health. In this study, we developed a simple method for GABA production from sodium glutamate using barley bran without any buffer or any coenzyme. We determined the optimal reaction conditions of the GABA production using barley bran as described below, reaction temperature: 20 °C, initial barley bran concentration: 150 mg/mL, initial sodium glutamate concentration: 10 mM, reaction time: 6 h. Under optimal conditions using barley bran, the concentration of GABA reached 11.0 mM (containing GABA from barley bran) from 10.0 mM of sodium glutamate; however in using wheat and rice bran, the GABA concentrations were only 3.9 and 0.8 mM, respectively. To apply the water containing GABA produced from sodium glutamate using barley bran (WGBB) to beer brewing, we prepared wort using WGBB. The wort contained a large amount of GABA (257 μg/mL) without lowering the other wort qualities.