动物蛋白与植物蛋白对甜菜苷的热保护作用机制研究

Study of the Thermal Protection Mechanism of Animal Proteins and Plant Proteins on Betanin

为探究不同蛋白质对甜菜苷的热保护作用,明晰其保护机制,本文拟采用两种动物蛋白(乳铁蛋白和β-乳球蛋白)、两种植物蛋白(大米蛋白和大豆分离蛋白)为原料,采用浊度、紫外光谱、粒径、分子模拟等手段表征蛋白-甜菜苷复合物的形成和相互作用机制。结果表明,四种蛋白质均能提高甜菜苷的热稳定性,保护效果为:乳铁蛋白>大豆分离蛋白>β-乳球蛋白≈大米蛋白,蛋白质对甜菜苷热稳定性的提高与蛋白-甜菜苷复合物的形成有关。通过浊度、紫外光谱、粒径的实验结果推测,甜菜苷与乳铁蛋白、β-乳球蛋白、大豆分离蛋白的结合程度高于大米蛋白,这可能是由于大米蛋白的低溶解度和紧密结构造成的。此外,相互作用和分子对接的结果显示,乳铁蛋白与甜菜苷主要通过氢键和静电相互作用结合,β-乳球蛋白与甜菜苷主要通过氢键发生相互作用,大米蛋白与甜菜苷主要通过疏水相互作用结合,大豆分离蛋白与甜菜苷主要通过氢键和静电相互作用结合。本研究为蛋白-天然色素的相互作用及甜菜苷的护色研究提供理论基础。

In order to explore the thermal protective effects of different proteins on betanin and clarify its protective mechanism,two animal proteins-lactoferrin and β-lactoglobulin,and two plant proteins-rice protein and soybean protein isolate were used.The formation and interaction mechanism of protein-betanin complex were characterized from turbidity,UV spectrum,particle size,and molecular simulation.The results showed that all the four proteins could improve the thermal stability of betanin,the protective effect was:Lactoferrin>soy protein isolate>β-lactoglobulin≈rice protein.The improvement of the thermal stability of proteins to betanin was related to the formation of protein-betanin complex.The results of turbidity,UV spectrum and particle size experiments suggested that the affinity of betanin with lactoferrin,β-lactoglobulin and soy protein isolate was higher than that of rice protein,which might be caused by the low solubility and tight structure of rice protein.In addition,the results of interaction and molecular docking showed that lactoferrin and betanin were mainly bound through hydrogen bond and electrostatic interaction,hydrogen bond played a dominant role in the interaction between β-lactoglobulin and betanin,the main interaction between rice protein and betanin was hydrophobic interaction,and soy protein isolate bound to betanin mainly by hydrogen bond and electrostatic interaction.This study provides a theoretical basis for protein-natural pigment interaction and the research of protection of betanin.