Abstract:

The content of γ-aminobutyric acid (γ-GABA), one of the main functional components in rice, changes with the parts and the germination periods of rice. This study aimed to analyze the changes in γ-GABA content in differert parts of rice and brown rice of 26 varieties (containing 12 japonica varieties and 14 indica varieties) that have been recently bred in Yunnan province or Zhejiang province and were grown in Xinping county in Yunnan province during germination. The results showed that Diannong S-1/Dianjing 8, HIPj 1, Wendao1/ IR 36 and Wendao 2/IR 36 had the highest γ-GABA content among the 26 rice varieties; the γ-GABA contents in different parts of rice before germination decreased in the following order: rice germ ＞ rice husk ＞ brown rice ＞ polished rice; the germination activation for 24－28 h could significantly promote the accumulation of γ-GABA in rice and brown rice, showing a trend of first increase and then decrease, and the γ-GABA content in brown rice reached maximum at 24 h of germination; the accumulation rate and quantity in different parts of germinated rice and germinated brown rice were different, and the γ-GABA contents in different parts decreased in the following order: rice germ ＞ brown rice ＞ polished rice ＞ rice husk; after germination activation, the γ-GABA accumulation quantity in brown rice was more than that in rice, and the average content of γ-GABA in rice germ of 12 japonica varieties was higher than that of 14 indica varieties.

Key words: rice, γ-aminobutyric acid, germination, brown rice