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This study investigates the effects of moisture content control on the characteristics, properties, and in vitro starch digestion of roasted rice powder made from natural high-resistant starch (RS) rice varieties. The results demonstrate that adjusting the moisture content before roasting significantly affects the RS content of the roasted rice powder. Among various moisture levels tested, the addition of 15% water (rice-to-water ratio of 85:15) before roasting resulted in the highest RS content, reaching 22.61%. Several key parameters of the rice samples before and after optimal moisture control were analyzed, including thermal stability, chain length distribution, volatile flavor composition, and scanning electron microscopy. Additionally, in vitro digestion properties were measured. The findings revealed that the volatile flavor compounds in the high-RS roasted rice significantly increased compared to non-roasted rice. Moreover, the thermal stability of the rice samples improved, and the chain length distribution exhibited significant changes. The water absorption and expansion properties were significantly lower in the high-RS roasted rice. Furthermore, the in vitro starch digestion of the roasted flour made from high-RS rice showed a significantly lower digestion rate compared to common rice, indicating a lower starch hydrolysis index in high-RS rice with the sbe-rs genotype. Overall, the roasting process of natural high-RS rice modifies its characteristics, increases the RS content, enhances the flavor, and results in a lower starch digestion rate compared to common rice. This study provides valuable data for the food industry to promote the application of high-RS rice varieties with mutations in the SBEIIb gene, such as Youtangdao2 (YTD2). [ABSTRACT FROM AUTHOR]

In this study, Xiushui 134Bt, a highly insect-resistant rice transgenic material with stable expression of CryIAc1 gene in rice plants and no significant changes in main agronomic traits, was obtained by means of Agrobacterium-mediated transformation method using japonica rice Xiushui 134 as receptor material. Biosecurity of the transgenic rice Xiushui 134Bt was assessed by rat feeding experiments. Wistar rats were fed a nutritionally balanced diet supplemented with 35% Genetically Modified (LGM) or 70% Genetically Modified (HGM) Xiushui 134Bt, respectively, for 90 days. Compared with the wild-type group (Xiushui 134), there were no significant differences in body weight, total food intake, food conversion rate, relative organ weight, blood routine, blood physiological or biochemical parameters, or histopathological examination between LGM and HGM Bt groups (p > 0.05). These results indicate that the transgenic rice Xiushui 134Bt is non-toxic in laboratory animals and provide guidance for the future commercial release of the transgenic rice Xiushui 134Bt in China. [ABSTRACT FROM AUTHOR]