冷冻面制品在食品行业发展迅速，但在冻藏过程中对面制品品质影响的关键性问题仍未明朗。本研究采用小角X射线散射仪（SAXS）探讨了恒温冻藏（-18 ℃）对小麦面筋蛋白分子链构形、均方根旋转半径（Rg）及分子量的影响。实验发现，冻藏前，面筋蛋白分子在500 mM乙酸溶液中链结构较疏松，属于质量分形（分形维数Dm: 2.05），呈现网络状的结构。随着冻藏时间的延长，Dm值呈现下降的趋势，表明面筋蛋白高聚物的链结构逐渐疏松，同时发现在冻藏过程中面筋蛋白平均分子量和Rg都随着冻藏时间的增加也呈现下降趋势，并且Rg与Dm的变化正相关，说明在冻藏过程中由于冰晶的重结晶等作用使得高聚物发生了解聚现象，造成了面筋蛋白分子链的断裂，从而使得其网络结构的疏松。

Frozen flour products have been rapidly developed in the food industry, while some key scientific issues on the effects of the frozen storage process on the quality of flour products remain unclear. In this study, the effects of frozen storage (-18 ℃) on the molecular chain configuration, root mean square radius of gyration (Rg), and molecular weight of hydrated gluten were studied by small-angle X-ray scattering (SAXS). The results showed that before frozen storage, gluten molecules had a relatively loose chain structure in a 500 mM acetic acid solution, possessed a mass fractal structure (mass fractal dimension (Dm): 2.05), and a network structure. With elongated storage time, Dm value tended to decrease, indicating a gradually loose chain structure of gluten protein polymers. The Rg value and average molecular weight of gluten also tended to decrease with increasing frozen storage time and the change of Rg was positively correlated with that of Dm. These results demonstrated that depolymerization occurred during the frozen storage process due to the ice recrystallization, resulting in breaks in gluten molecule chains and a loose network structure.

国家自然科学基金资助项目（31301412、31130042）；国家科技支撑计划（2012BAD37B01）；广东省自然科学基金资助项目（S2013040014403）；大学生省级创新训练项目（1056413084）