稻米作为我国膳食中的重要碳水化合物来源之一，其淀粉消化特性对于餐后血糖稳态的维持具有重要作用，因此深入探究其淀粉消化特性的具体机制意义重大。淀粉分子结构是决定其消化特性的重要因素，但现有报道多集中于不同直链淀粉含量对稻米消化特性的影响，而忽略了直链淀粉结构在其中发挥的作用。本项目以“直链淀粉精细分子结构-糊化、回生过程中淀粉超分子结构有序性的演变-消化特性之间的关联”为主线，选取不同直链淀粉结构的稻米品种，利用体积排阻色谱等方法表征其淀粉分子结构，通过小角度X射线散射等技术系统性监测其淀粉超分子结构在不同糊化、回生条件下的动态演变过程，结合与淀粉消化特性的相关性分析，以及淀粉超分子结构对消化酶的物理阻碍和化学吸附作用，揭示直链淀粉精细分子结构对淀粉消化特性的影响机制。在此基础上，利用动物体内实验验证相关机制。本项目将为直链淀粉在慢消化稻米育种及特膳食品开发等方面提供理论依据。

Rice is one of the main sources of carbohydrates in our diet, with its starch digestibility plays an important role in maintaining postprandial blood glucose homeostasis. Therefore, it is of great significance to deeply explore the specific mechanism of rice starch digestion characteristics. The molecular structure of starch is an important factor determining its digestive properties, but the existing reports mostly focus on the effect of different amylose content on the digestive properties of rice, and ignore the role of amylose fine molecular structures in it. This project thus focuses on the relations among amylose fine molecular structures, the evolution of starch supramolecular structures during gelatinization and retrogradation, and the digestibility of rice starches. Rice varieties with different amylose structures would be selected, with the dynamic evolution of their starch supramolecular structures under different gelatinization and retrogradation conditions systematically monitored by using a combination of small-angle X-ray scattering and other technologies. The starch fine molecular structures are characterized by size-exclusion chromatography (SEC). Through the correlation analysis with starch digestion characteristics, combined with the physical hindrance and chemisorption of starch supramolecular structure on digestive enzymes, the mechanisms of amylose fine molecular structure regulating starch digestion characteristics would be revealed. Furthermore, animal in vivo experiments would be applied to verify and improve related mechanisms. This project will provide a theoretical basis for amylose utilization in the breeding of rice varieties with slowly digestible starch and the development of special dietary products for diabetic patients.