关键词: 发芽糙米, 盐胁迫, γ-氨基丁酸, 蛋白组分

Abstract: In this paper, in order to provide a scientific basis for the evaluation of the nutritional value of germinated brown rice and for new product development from this plant material, γ-aminobutyric acid (GABA) content, glutamic acid decarboxylase (GAD) activity, respiration rate and four protein components in germinated brown rice from Nanjing 46 japonica rice were measured under salt stress. The results showed that salt stress reduced the germination rate of brown rice and increased respiration rate. GABA concentration and GAD activity reached their highest levels of 121.714 9 mg/100 g mf and 5.784 5 U/g mf on the 3rd day under salt stress. Under normal and salt stress conditions, similar trends were observed for the albumin content in germinated rice, which decreased followed by an increase. The globulin content in germinated rice under normal conditions gradually fell, while it rose firstly and then decreased under salt stress. Under salt stress, the gliadin content remained almost unchanged. The glutenin content showed an increase followed by a decrease under both normal and salt stress conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results showed that the large subunits were degraded into smaller ones during germination, which were essential for physiological activities. On the 2nd day, the 28.6 and 58.7 kDa subunits of albumin and the 24.4 and 40.0 kDa subunits of globulin were significantly degraded. Gluten began to accumulate on the 3rd day, but no significant changes were observed for its major subunits. The minor subunit (15.8 kDa) of gliadin was greatly degraded.

Key words: germinated brown rice, salt stress, γ-aminobutyric acid, proteins