茶多酚含量是评价茶饮料质量的重要指标,国家标准《茶饮料》(GB/T 21733-2008)附录 A 采用乙醇沉淀-酒石酸亚铁比色法测定茶饮料中茶多酚的含量,该方法适用范围较小,特别是奶茶等使用了乳化剂、稳定剂的饮料产品,存在比色溶液浑浊的问题,直接影响检测结果的准确性.本研究通过改进样品预处理方法,使用菠萝蛋白酶酶解,解决了比色溶液浑浊的问题,提高了奶茶饮料中茶多酚含量测定的精密度和准确度.方法回收率为99.1%～102.0%,相对标准偏差RSD为 0.23%～0.37%(n=6).
Research and Application of Improved Method for Determination of Tea Polyphenols in Milk Tea Beverage
The content of tea polyphenols is an important indicator for evaluating the quality of tea beverages.The national standard method Tea beverage(GB/T 21733-2008)Appendix A adopts the ethanol precipitation-ferrous tartrate colorimetric method to determine the content of tea polyphenols in tea beverages.This method has a small scope of application,especially for milk tea and other beverage products that use emulsifiers and stabilizers.There is the problem of turbidity of the colorimetric solution,which directly affects the accuracy of the test results.In this study,the sample pretreatment method was improved,and pineapple protease was used to solve the problem of turbidity of the colorimetric solution.Hence,the precision and accuracy of the determination of tea polyphenols in milk tea beverages was improved.The recovery rate of the method was 99.1%～102.0%,and the relative standard deviation RSD was 0.23%～0.37%(n=6).
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