茶叶提取液的循环伏安电位测定及与总还原力的相关性

摘要

The tea polyphenols contents and total reducing power of 28 kinds of green tea,oolong tea and black tea from different geographical regions were determined by means of Folin-Ciocalteu (FC)and ferricyanide reduction(FR)assays.The redox potentials of above tea extracts were analyzed by cyclic voltammetry(CV).The relationship among the determined results obtained from FC,FR and CV methods were studied.The difference in accuracy between the CV and FR tests were also evaluated.The results showed that the redox potential,total reducing power and content of the tea polyphenols were all interrelated.Compared with the FR assay,the CV method had vecovery and RSD of 100.3％ and 1.10％,resbertively,suporior to the FR method (102.0％ and 2.41％).Thus the CV method was move simple,convenient,time-effective and precise that the FR method.This research confirmed the feasibility of CV method to rapidly measure the total reducing power and evaluate the quality of tea,which would provide theoretical and methodological guidance for the evaluation of tea quality based on the total reducing power.%采用福林酚比色法(FC)和铁氰化钾还原法(FR)分别对28种不同产地的绿茶、乌龙茶、红茶的茶多酚含量和总还原能力进行了测定,同时应用循环伏安法(CV)测定了茶叶提取液的氧化还原电位,并对茶多酚含量、总还原力及氧化还原电位之间的相关性进行了分析,比较了CV和FR方法的准确性.结果表明,以上三项指标两两之间存在良好的相关关系,CV方法可以评价茶叶提取液的总还原能力.CV法加标平均回收率和RSD分别为100.3％,1.10％,优于FR方法测定值(102.0％,2.41％).与FR方法相比,CV方法具有操作简便、快速精准的优点.可应用于茶叶品质的快速评价本研究的结果将为基于还原力评价茶叶品质提供理论指导和方法学支撑.