Therefore, the effect of phosphate buffer concentrations (0-200 mM) on GABA production was investigated.
The results showed that rice bran with phosphate buffer at a concentration of 80 mM at pH 5.6 with a rice bran to phosphate buffer at a ratio of 1-8 (weight per volume) produced the highest GABA content (p 0.05).
GABA production was increased about 2.7 times in the phosphate buffer system compared with the control and about 11 times compared to the initial GABA content (0.58 mg/g of bran) in the rice bran.
The results indicated that incubation time, buffer type and concentration significantly affect GABA production using rice bran