GABA (GAMMA-AMINOBUTYRIC ACID) PRODUCTION OF MUNG BEAN (PHASEOLUS AUREUS) DURING GERMINATION AND THE COOKING EFFECT

Gamma-aminobutyric acid (GABA), a four carbon amino acid produced by the decarboxylation of L-glutamic acid, provides many beneficial effects on human health including decreasing blood pressure and controlling stress. GABA is widely distributed in nature and also found in many kinds of germinated grains such as barley and brown rice. Mung bean (Phaseolus aureus) was used in this research to study GABA production during germination process. Mung bean was soaked and incubated for 0, 6, 12, 24, 36, and 48 h. The GABA content was determined by HPLC analysis. In addition, dietary fiber content, antioxidant activity, and cooking effect on GABA content of germinated mung bean were also evaluated. The important finding was that mung bean could be a potential source of GABA production. The amount of GABA significantly increased during germination and the highest production of GABA (80.68 mg/100 g dry weight) was found at 24 h of incubation period. The IDF is the main dietary fiber fraction in mung bean and its content increased up to 20.57 g/100g (dry weight) after soaking and incubation for 24 h. The DPPH activity of germinated mung bean slightly decreased and total phenolics content showed no significant change during germination. Additionally, all the cooking processes were found to decrease GABA in germinated mung bean. However, microwave was found to be the least destructive cooking method for GABA content in germinated mung bean.