以抗坏血酸（Ascorbic Acid，Asc）和过氧化氢（Hydrogen Peroxide，H2O2）为引发剂，研究乳清分离蛋白（Whey Isolate Protein，WPI）与表没食子儿茶素没食子酸酯（(-)-Epigallocatechin Gallate，EGCG）接枝聚合动力学。系统研究活化时间、引发剂浓度、单体浓度和温度对接枝量的影响，通过测定反应级数和表观活化能，建立接枝反应动力学方程。结果表明，在Asc/H2O2体系中，由抗坏血酸自由基（Asc-•）介导WPI与EGCG接枝反应。当反应条件为Asc浓度0.014 mol/L，H2O2浓度0.10 mol/L，溶液pH值6，温度308.15 K以及活化时间120 min时，接枝量为42.08 mg/g。基于上述结果，我们可以得到在Asc浓度0.01~0.022 mol/L，H2O2浓度0.09~0.12 mol/L，EGCG浓度0.001 2~0.004 2 mol/L，温度298.15~308.15 K变化范围内，建立了WPI接枝EGCG的聚合速率方程，聚合反应的表观活化能E=12.96 kJ/mol。研究结果为蛋白质的结构设计和可控制备提供理论指导，拓宽蛋白质在食品工业中的应用。

Graft polymerization of (-)-epigallocatechin gallate (EGCG) onto whey protein isolate (WPI) was investigated using ascorbic acid (Asc) and hydrogen peroxide (H2O2) as a redox system. The effects of different reaction parameters on the graft yield; activation time, initiator concentration, monomer concentration, and temperature were determined, and the kinetic equation for the graft polymerization reaction was established from the reaction level and apparent activation energy. The results demonstrated that, in an Asc/H2O2 system, acid free radicals (Asc•-) mediate the graft polymerization of WPI and EGCG, with the graft yield reaching 42.08 mg/g under an ascorbic acid concentration of 0.014 mol/L, H2O2 concentration of 0.10 mol/L, pH 6, temperature of 35 ℃, and activation time of 120 min. Based on the above results, a calculation equation describing the WPI-EGCG polymerization rate was obtained for reactions under an Asc concentration range of 0.01~0.022 mol/L, H2O2 concentration range of 0.09~0.12 mol/L, EGCG concentration of 0.0012~0.0042 mol/L, and temperature of 298.15~308.15 K. An activation energy of 12.96 kJ/mol was obtained for polymerization. The results provide theoretical guidance for the structural design and controllable preparation of proteins, thus broadening the application of proteins in the food industry.

国家自然科学基金项目（31501471）