Abstract

A voltammetric method for evaluating polyphenol–protein interactions was developed based on the oxidation of polyphenols at an electrode modified with multi-walled carbon nanotubes and electropolymerized quercetin. Tea polyphenols (catechin and epigallocatechin gallate) and milk proteins (casein, bovine serum albumin, and β-lactoglobulin) were considered as model systems. It was found that proteins bind the test polyphenols (from 10 to 60%) with increasing protein content (from 1 : 0.25 to 1 : 1.5, by volume) in the mixture by decreasing the fraction of free polyphenol. The developed approach was used to assess the effect of milk on the antioxidant properties of tea (green, white, oolong, and black teas), which were expressed through the antioxidant capacity (AOC) parameter. A statistically significant decrease in the AOC of tea by a factor of 1.8–23 in the presence of 20 vol % milk was demonstrated.

中文翻译：

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伏安法评价茶多酚与蛋白质的相互作用及其对茶叶抗氧化能力的影响

摘要

建立了一种基于多壁碳纳米管和电聚合槲皮素修饰的电极上多酚氧化的伏安法，用于评估多酚与蛋白质的相互作用。茶多酚（儿茶素和表没食子儿茶素没食子酸酯）和乳蛋白（酪蛋白，牛血清白蛋白和β-乳球蛋白）被视为模型系统。发现通过减少游离多酚的比例，蛋白质以增加的混合物中蛋白质含量（按体积计从1∶0.25至1∶1.5）结合测试多酚（10-60％）。所开发的方法用于评估牛奶对茶（绿茶，白茶，乌龙茶和红茶）的抗氧化性能的影响，这些抗氧化性能通过抗氧化能力（AOC）参数表示。茶的AOC在统计上显着降低了1。