Three Thailand rice varieties (cv. Niaw Dam Peuak Dam, Sangyod Phatthalung and Chiang Phatthalung) were germinated and their γ-aminobutyric acid (GABA) content was monitored. Optimum germination conditions to maximize GABA content in brown rice were determined. The brown rice was first soaked in various solutions (buffer solution pH 2, 3, 5, and 7 and distilled water) at room temperature (30±2°C) for 5 hours, followed by germinating in either open or closed vessel for 12, 24, 36, and 48 hours. Results indicated that the highest GABA content was obtained when the rice was soaked in a citrate buffer with pH 3 and germinated in closed vessel for 36 hours, Sangyod Phatthalung and Chiang Phatthalung, and for 48 hours, Niaw Dam Peuak Dam. Compared to regular brown rice, the GABA content in germinated brown rice increased 9.43- 16.74 times. Germination also increased the ferulic acid 1.12-1.43 times and significantly decreased the phytate content while the γ-oryzanol content was in the same level for both un-germinated and germinated brown rice.
