中文摘要：

为研究超声处理大豆分离蛋白与壳聚糖相互作用及其对复合物结构性质的影响,利用紫外-可见吸收光谱和荧光光谱研究超声处理大豆分离蛋白与壳聚糖的相互作用,通过SDS-PAGE电泳（十二烷基硫酸钠聚丙烯酰胺凝胶电泳）、复合物动态光散射粒度分析、表面电荷和浊度等测定,解析了超声处理对大豆分离蛋白-壳聚糖复合物结构变化与功能性质之间的关系。结果表明,随着超声功率的增加,复合物的紫外-可见吸收光谱的最大吸收峰逐渐升高且发生红移;荧光强度先降低后增加,超声600 W处理时内源荧光强度最大;超声处理影响了大豆分离蛋白亚基组成,主要促进了7S亚基与壳聚糖的相互作用;复合物的粒径先降低后增大;300～500 W处理的复合物ζ-电位表面电荷密度较大,浊度明显降低且溶液分散均匀、性质稳定。说明相对低功率时复合物形成得较为稳定,但超声处理进一步增大后,蛋白质发生不溶性聚集和重排,影响了大豆分离蛋白与壳聚糖之间的相互作用,不同复合物中蛋白质与壳聚糖的相互作用影响了氨基酸残基的微环境、蛋白质的三级结构和分子柔性,进而影响复合物结构和功能特性。

英文摘要：

The objective was to evaluate the interaction between ultrasonic treatment soybean protein isolate and chitosan, and the structural properties of the complexes. The interaction was studied by UV - Vis absorption and fluorescence spectroscopy. The relationships between structure changes and functional properties of soybean protein-chitosan complexes through SDS - PAGE, dynamic light scattering particle size analysis, surface charge and turbidity measurement were investigated. The results showed that with the increase of ultrasonic power, the maximum absorption peak of UV - Vis absorption spectrum was gradually increased and occurred red-shifted; the fluorescence intensity was firstly decreased and then increased. The intensity of the endogenous fluorescence was the highest at 600 W. Ultrasonic treatment affected soybean protein isolate subunit composition and mainly promoted the interaction between 7S subunits and chitosan. The particle size of the complex was firstly decreased and then increased. The charge potential of the complexes was larger under 300 ~ 500 W than those under others. The turbidity was also decreased, which was beneficial to homogeneous distribution and stability of the solution. The results showed that the formation of the complex was relatively stable at low power, but the interaction between soy protein isolate and chitosan was affected by the insoluble aggregation and rearrangement of the protein after high power ultrasonic treatment. The interaction of different complexes affected the microenvironment of amino acid residues, the tertiary structure and molecular flexibility of soybean protein isolate, and then impacted the structure and functional properties of the complexes.