Factor Affecting on Accumulation of Gamma-Aminobutyric Acid (GABA) in Rice Germ (Khao Dawk Mali 105)

GABA content in rice germ is affected by many factors. The objective of this study was to screen significant factors which affecting on GABA content. The four factors (pH , CaCl 2 concentration , soaking temperature, and soaking time) were tested using the eig ht-run Plackett-Burman design. Factors were considered to have significant effects on response at a = 0.05. The results revealed that soaking temperature and soaking time most significantly affected GABA content (positive effect). Subsequently, effect of soaking temperature and time were conducted by soaking the rice germ in 0.5 mmol/L CaCl 2 , pH 6 at 30, 40, and 50 ° C and in various time: 1, 2, 4, 8, and 16 h. The results indicated that during soaking rice germ at 40 ° C for 8 h had the highest in GABA content (307.1 mg/ 100 g of rice germ, dry basis).