大豆分离蛋白-花青素复合物的制备及其蛋白结构与功能性质分析

摘要

大豆分离蛋白经热处理后与花青素进行复合形成复合物,采用荧光光谱表征复合体系构象变化,以溶解性、乳化性、乳化稳定性、粒度分析及Zeta电位为指标分析该复合体系中大豆分离蛋白二级结构的变化与功能性质表达之间的关系.结果表明:在pH?7.4的条件下,热处理大豆分离蛋白与花青素复合后,大豆分离蛋白的Zeta电位绝对值显著增大,乳化性、乳化稳定性显著提高,但溶解性显著下降.通过荧光光谱分析发现花青素对热处理大豆分离蛋白的荧光猝灭机制为静态猝灭,蛋白与花青素间形成了结合位点数近似于1的复合物,三维荧光光谱结果表明花青素的复合使得蛋白质多肽链的骨架伸展,蛋白结构发生变化.%This paper is focused on the effect of interaction with anthocyanin on the structure and function of denatured soybean protein. Fluorescence spectroscopy was used to study the conformational changes of the complexes. The relationship between structural change and functional properties was analyzed through determination of solubility, emulsifying ability, emulsifying stability, particle size analysis and Zeta potential analysis. The results showed that the absolute value of Zeta potential as well as emulsifying activity and emulsion stability of denatured soybean protein increased significantly after complexation with anthocyanin at pH 7.4, whereas its solubility decreased. The fluorescence spectra showed that the fluorescence quenching of heat-treated soybean protein by anthocyanin was a static quenching process with the formation of binding sites close to 1. The three dimensional fluorescence spectra indicated that complexation with anthocyanin extended the protein polypeptide backbone and changed the protein structures.