Effects of molecular weight and chitosan concentration on GABA (γ-aminobutyric acid) contents of germinated brown rice

The aim of this study was to investigate the effects of molecular weight and concentrations of chitosan on the germination of brown rice. Brown rice was germinated at 30°C for three days in various chitosan solutions. The germination rate of the brown rice increased with increasing concentrations of chitosan solution, and was higher in the chitosan solution than in water. GABA content increased with increasing germination time and chitosan solution concentration. As the molecular weight of the chitosan decreased, germination rate and GABA content increased in the brown rice. The GABA content of germinated brown rice using low molecular weight chitosan A in a 100 ppm solution was 5145.5 nmole/g. This is approximately a five times higher value than that of the water-germinated brown rice. Texture properties were enhanced in all the germinated brown rice samples in chitosan solution compared to the brown ricegerminated in water. These results indicate that chitosan solution treatment can increase germination rate and GABA synthesis activity in brown rice during germination, and can also improve the texture properties of brown rice.