Analysis of active components and physicochemical characteristics of Pu-erh raw tea at different storage temperatures
To investigate the changes in active components and physicochemical characteristics in Pu-erh raw tea under different temperature storage conditions,high-performance liquid chromatography(HPLC)technology was used to determine the content of 6 polyphenolic compounds,including GA,C,and EC,sa well as caffeine in Pu-erh raw tea under different temperature storage conditions(5,20,and 35℃),and to detect the changes in tea color and pH value.The results showed that the separation of 7 compounds by this method was good,and the mass concentration range showed a good linear relationship with its peak area.The relative standard deviation of precision,stability,and repeatability were all less than 5%,and the average recovery rate was 99.45%to 100.96%(RSD was 0.08%to 1.99%);temperature storage conditions had no significant effect on the color of tea soup;the pH value shows fluctuating changes.The pH changes of tea soup under storage conditions of 5 and 20℃were relatively gentle,while the change was more significant at 35℃;the content changes of the seven compounds showed a trend of first decreasing and then slowly increasing.In summary,HPLC method is simple,accurate,and has good reproducibility,and can simultaneously determine the content of GA,EC,EGCG,GCG,ECG,and caffeine components,and storing at 5-20℃is more conducive to the stability of tea pH and compound content,providing a reference for the quality control of Pu-erh raw tea storage.
Pu-erh raw teapolyphenolic compoundscaffeinestorage temperaturehigh performance liquid chromatography
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