米糠球蛋白的糖基化改性及其与两种多酚的非共价作用

Glycosylation Modification of Rice Bran Globulin and Its Non‐Covalent Interaction with Two Polyphenols

采用干法美拉德反应法对米糠球蛋白进行糖基化改性,在此基础上研究糖基化的米糠球蛋白与两种多酚的非共价结合,结合荧光光谱、红外光谱、差示扫描量热仪等对二者相互作用机制进行表征和分析。结果发现,糖基化后米糠球蛋白的微观形态发生改变,抗消化性和抗氧化性均得到了改善。槲皮素与白藜芦醇均能导致糖基化蛋白的荧光淬灭,且白藜芦醇使糖基化蛋白的荧光发射波长发生了红移。在这种非共价结合中氢键/范德华力起主要作用。荧光拟合数据表明糖基化蛋白可同时结合白藜芦醇和槲皮素,结合位点数和结合常数分别为0.014 7和0.002 23,其结合能力小于分别单独结合白藜芦醇和槲皮素分子。糖基化蛋白及糖基化蛋白-多酚非共价复合物的粒径均高于米糠球蛋白,且当糖基化蛋白同时与两种多酚结合时,粒径最大。此外,糖基化蛋白与两种多酚非共价结合后能显著提高蛋白的热稳定性及抗氧化能力,并介于糖基化蛋白单独结合白藜芦醇和槲皮素分子之间。

The dry Maillard reaction method was used to glycosylate rice bran globulin.On this basis,the noncovalent binding of glycosylated rice bran globulin with two polyphenols was studied.The interaction mechanism between them was characterized and analyzed by fluorescence spectroscopy,infrared spectroscopy,differential scanning calorimetry,etc.The results showed that the micromorphology of rice bran globulin was changed after glycosylation,and the anti-digestibility and antioxidant properties were improved.Quercetin and resveratrol could both cause fluorescence quenching of glycosylated proteins,and resveratrol caused a red shift in the emission peak of glycosylated proteins.In this non-covalent binding,hydrogen bonding/van der Waals forces played a major role.Fluorescence fitting data showed that glycosylated proteins could bind both resveratrol and quercetin simultaneously,with binding sites and constants of 0.0147 and 0.00223,respectively.The binding ability was lower than that of binding resveratrol or quercetin molecules separately.The particle sizes of glycosylated proteins and glycosylated protein-polyphenol non-covalent complexes were higher than that of rice bran globulin,and the maximum particle size occurred when glycosylated proteins were bound to two polyphenols simultaneously.In addition,the non-covalent binding of glycosylated proteins with two polyphenols could significantly improve the protein’s thermal stability and antioxidant capacity,and this improvement was situated between the glycosylated proteins binding to resveratrol and quercetin molecules alone.