Stimulation of γ-Aminobutyric Acid Synthesis Activity in Brown Rice by a Chitosan/Glutamic Acid Germination Solution and Calcium/Calmodulin = Stimulation of γ-Aminobutyric Acid Synthesis Activity in Brown Rice by a Chitosan/Glutamic Acid Germination Solution and Calcium/Calmodulin

다국어 초록 (Multilingual Abstract)

Changes in the concentrations of r-aminobutyric acid (GABA), soluble calcium ions, glutamic acid, and the activity of glutamate decarboxylase (GAD) were investigated in non-germinated vs. germinated brown rice. Brown rice was germinated for 72h by applying each of the following solutions :(1) distilled water, (2) 5 mM lactic acid, (3) 50 ppm chitosan in 5mM lactic acid, (4) 5mM glutamic acid, and (5) 50ppm chitosan in 5mM glutamic acid. GABA concentrations were enhanced in all of the germinated brown rice when compared to the non-germinated brown rice. The GABA concentration was highest in the chitosan/glutamic acide that germinated brown rice at 2,011 nmol/g fresh weight. The concentrations of glutamic acid were significantly decreased in all of the germinated rice, regardless of the germination solution. Soluble calcium and GAD were higher in the germinated brown rice with the chitosan/glutamic acid solution when compared to the rice that was germinated in the other solutions. GAD that was partially purified from germinated brown rice was stimulated about 3.6-fold by the addition of calmodulin in the presence of calcium. These data show that the germination of brown rice in an chitosan/glutamic acid solution can significantly increase GABA synthesis activity and the concentration of GABA.