挤压调控复合米食用品质加工过程中米谷蛋白-淀粉分子结构演化规律研究

流变、热力和质构等特性对复合米食用品质影响显著，而米谷蛋白和淀粉的结构变化是决定其物性的根本因素，但二者挤压复合过程中精细结构演变规律、主导复合物（复合米）品质形成的关键结构及形成机制尚不明确。针对不同挤压条件制备的米谷蛋白-淀粉复合物，利用动态剪切流变仪和质构仪，考察复合物储能模量、损耗模量和回复性等变化，建立关联复合条件的挤压动力学模型；采用高效体积排阻色谱、1H NMR、X-射线衍射和固体核磁共振结合魔角旋转/交叉极化技术，研究淀粉分子链结构、晶体结构、blocklets止水塞等层级结构；通过傅里叶红外光谱、圆二色谱和ANS荧光探针技术，获取米谷蛋白亚基组成、空间构象、分子间作用力等高级结构信息；采用分子模拟技术模拟米谷蛋白-淀粉分子结构变化及挤压互作关系，明确致复合物宏观属性差异的关键结构。阐明米谷蛋白-淀粉精细结构挤压演变规律，揭示调控挤压复合米食用品质的分子基础以指导定向加工。

Rheological, thermal and textural properties have a significant effect on the edible quality of texturized rice produced by the extrusion processing, furthermore, the structural changes of starch and rice glutenin are the fundamental factor determining their physicochemical properties, however, the fine structure evolution, key structures dominating the quality development of texturized rice and formation mechanism of rice glutenin-starch complexes in the extrusion melting processing are not clear yet. The rice glutenin-starch extruded complexes obtained under different extrusion conditions are selected as the materials to investigate their storage modulus, loss modulus and adhesiveness by dynamic rheometer and texture analyzer, and build the extrusion kinetics model to correlate extrusion conditions with physicochemical properties of extruded complexes. High-performance size exclusion chromatography (HPSEC), nuclear magnetic hydrogen spectrometry (1H-NMR spectroscopy), X-ray diffraction (X-Ray) and solid-state cross polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C NMR) are employed to analyze changes in the molecular chains, crystalline structure, blocklets and other multi-levels structure of rice starch in the extruded complexes. FTIR, circular dichroism (CD) and ANS fluorescent probe are applied to obtain the detail information about structural changes in the sub-unit composition, spatial conformation and intermolecular forces of rice glutenin in the extruded complexes. To clarify the critical structure resulted in the difference in the macroscopic properties of extruded complexes, the molecular simulation techniques are employed to simulate the interaction between starch and rice glutenin and characterize structural changes of them at the molecular level. The study will elucidate the fine structure evolution of rice glutenin-starch under extrusion processing, and reveal the molecular basis that regulate the edible quality of extruded texturized rice to guide the directional specific processing.