The effect of defatting with organic solvent on accumulation of 4-aminobutyric acid (GABA) in the rice germ

The 4-aminobutyric acid (gamma -aminobutyuric acid, GABA) was accumulated s teeply in the rice germ during water soaking. GABA-enriched rice germ work effectively to lower the blood pressure of patients of hypertension. Howeve r, the rice germ have a high amount of oil that: will be rancidity. In this study, we tried a deffating of the rice germ without inactivation of gulut amate dehydrogenase. The oil content was decreased to 3.9% (w/w) from 21.5% (w/w) and the accumulated GABA content increased to 328 mg/100 g from 251 mg/100 g after defatting of the rice germ with n-hexane for 2 h at 40 degre esC. High temperature of defatting decreased the oil content. There was no effect of defatting. temperature on the amount of accumulated GABA contents , However long time proceeding decreased the accumulated GABA content. Ther e was no effect to GABA-accumulation of solvent change to acetone from n-he xane. However, ethanol decreased the accumulated GABA content. And the resi due of solvent, n-hexane have no effect on GABA accumulation, but ethanol d ecreased the content of accumulated GABA during water soaking.