不同链/支比淀粉热挤压加工过程中的相变机理及流变学研究

淀粉的热挤压技术是近年来发展最快和最活跃的加工技术，涉及多学科交叉知识，广泛应用于食品与非食品体系的原料加工。为实现淀粉原料在加工中的结构精确修饰的先进理念，针对目前热挤压加工过程中淀粉相变机理和流变学理论体系还不够完善，还不能解决应用中的复杂问题。本项目拟从同源淀粉(玉米和小麦) 的分子链/支比、分支结构及构象的差异为出发点，采用Hakke 流变仪（密炼机、双螺杆挤出机）、DSC、SEM、同步辐射-小角XRD 等现代分析设备，对淀粉原料在挤出机内的流变行为和相变演化过程进行数值分析和物理模拟，将压力场、温度场、速度场等函数群的研究与淀粉的形态、结构、相变机理及流变性能的研究有机的结合起来，从分子水平上对淀粉的性质行为进行评估和预测，达到对淀粉分子的功能性设计。以期解决制约淀粉分子挤出改性过程中的关键理论和技术问题，为淀粉的修饰和精深加工提供基础数据和理论指导。

Thermal extrusion is one of the cutting-edge technologies used for starch processing, which involvs interdisciplinary knowledge, such as mixing,.stirring, heating, sterilization, phase transitons and rheology et al. However, there have been few literatures systematically and intensively reporting the rheological behavior and phase transitions of starch during extrusion. Current theory is far from fully satisfying general applications, in particular for the complex systems. Based on the microstructure difference of the starches from same resources (corn and wheat) with different amylose/amylopectin ratios, the mechansims of rheological behaviors and phase transitions will be studied in this project, in particularly focused on the dynamic properties and the effect of processing parameters during extrusion, as well as the relationship between properties and microstructures of starches. A mathematic model will be stablised to describ and predicate the effect of various phisical forces on the microsctructre and morphologies of starches. It is expected that the achievements of the project will provide a better understanding of the phase transitions and rheological behavior of starch and develop a new approach for product design and processing control of thermal procession and starch modification.