内源性物质对不同品种大米淀粉消化性的影响

近年来培育出了低高血糖生成指数（GI）大米品种，但是其产生低GI作用机理并不明确，内源性非淀粉物质作为大米关键成分，对不同GI大米淀粉消化率的影响值得探讨。本研究以典型的两种不同GI大米作为研究对象，探究了去除内源性非淀粉物质对大米淀粉体外消化性、理化性质和微观结构的影响。结果表明，对于低GI品种，蛋白质和膳食纤维的去除显著促进了淀粉消化，使最终消化率提升了7.37%~13.28%，但高GI品种的内源性非淀粉物质对于淀粉消化性的影响并不显著。在理化性质上，蛋白质和膳食纤维的去除将淀粉的膨胀力显著提升至17.83±0.30g/g~13.44±0.27g/g，显著改变了米粉的糊化特性和热力学特性，从而使其更容易糊化和消化。在微观结构上，去除蛋白质和膳食纤维使淀粉颗粒结构减小了3~8 μm，蛋白质、膳食纤维和淀粉的相互作用提高了米粉的有序度和聚集结构。

Effects of endogenous substances on starch digestibility in different rice varieties

In recent years, rice varieties with low and high glycemic index (GI) have been developed, but the mechanism of producing low GI is not clear. As the key components of rice, the effects of endogenous non-starch substances on the digestibility of rice starch with different GI are worth exploring. In this study, two typical GI rice varieties were used as research objects to explore the effects of removing endogenous non-starch substances on the in-vitro digestibility, physicochemical properties and microstructure of rice starch. The results showed that for the low GI rice varieties, the removal of protein and dietary fiber significantly promoted the digestion of starch, and the final digestibility increased by 7.37% to 13.28%, but the effect of endogenous non-starch substances on the digestibility of starch was not significant in the high GI rice varieties. In terms of physicochemical properties, the removal of protein and dietary fiber significantly increased the dilatability of starch to 17.83±0.30g/g~13.44±0.27g/g, and significantly changed the gelatinization properties and thermal properties of rice flour, thus making it easier to gelatinize and digest. In terms of microstructure, the removal of protein and dietary fiber reduced the grain structure of starch by 3~8 μm, and the interaction of protein, dietary fiber and starch improved the order degree and aggregation structure of rice flour.