Abstract:[Objective] This study explores the nutritional quality of germinated rice, aiming to develop its medicinal value. [Method] Five varieties of rice ('Shuijing 3''Zhiyou 151''Chunyou 167''9 You 418', and 'Ningxiangjing 9') were treated with ultrasonic waves, and then lactic acid bacteria and fermentation liquid were used instead of water as the culture medium for rice germination. The effects of combined ultrasonication and lactic acid bacteria treatment on the levels of total starch, amylose, resistant starch, and soluble protein of rice during the germination process were investigated. The structural changes were analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy, and the estimated glycemic index (eGI) was measured by in vitro simulated digestion experiment.[Result] The five varieties of rice reached a micro-germination state after 96 h of treatment, with the bud lengths ranging from 1.403 cm to 1.847 cm. The mass fractions of total starch, amylose, and resistant starch of five varieties of rice all showed a downward trend with the extension of germination time. After 96 h of germination, the mass concentrations of soluble protein of 'Zhiyou 151' and 'Ningxiangjing 9' were significantly lower than those before germination, while the mass concentrations of soluble protein of other varieties of rice showed no significant difference compared with those before germination. The Fourier transform infrared spectroscopy results showed that the infrared spectra of the five varieties of rice presented the same overall trend in five stages before and after germination. The absorption peak intensity at 3 500 cm-1 of rice among different germination stages varied greatly and gradually decreased with the extension of germination time. The scanning electron microscopy results showed that with the extension of germination time, the smooth surface of rice gradually became rough and uneven. The results of the in vitro simulated digestion experiment showed that the eGI of five varieties of rice germinated for 96 h were all lower than 55, indicating that germinated rice was low-glycemic index (GI) food.[Conclusion] Germinated rice can effectively replace polished rice to address its high-GI concerns, and the germinated rice grains become softer, which is beneficial for the development and utilization of subsequent products.
