Variation Of Ann Tea Polyphenols And Its Extraction And Isolation During Processing And Storage

Ann tea is a kind of black tea,which produced in Keemun,Anhui Province.With its benefits of detoxification,relieving a cough and helping digestion,Ann tea is popular in Guangdong and Southeast Asia district.For now,researches about black tea mainly focused on Fuzhuan brick tea,Pu'er tea etc.,but seldom studies of Ann tea have been reported.So it has great significance to conduct a systematic analysis of Ann tea,which will promote the development of Ann tea,accelerate the exploitation of Anhui summer tea and increase farmers' income.In this study,the main tea phenolic substances of the different processing stages and different years were quantitative analyzed.To judge the relationship between phenolics content and the sensory quality of the aged years,sensory of Ann tea were also been evaluated.Besides,Ann tea was extracted and fractionated by organic solvents.Column chromatographic methods were applied for isolation of chemical compositions,and the structures of compounds were identified.Based on the research,we mainly achieved the following results:1.During the processing,there was little variation in the content of total phenllic.Catechins,apart from GA(Gallic Acid)of which content increased by 80%,were all suffered from reduction;The theaflavin contents showed a trend of decrease;The contents of common flavonoids such as rutin,myricetin,quercetin and kaempferol have not changed significantly during this period.2.During storage,the content of total polyphenol has not changed greatly,but with the storage time inceasing,catechins,theaflavins were reduced.Tea catechins content before2008 were lower than its after.During this period theaflavin content also occurred plunged,while the content of flavonoids varied little.Sensory evaluation results of the different years' s teas showed there was a good correlation between quality and storage time.Generally,the tea produced within two or three years can not reflect the features of aged Ann tea.But with the extension of storage time,the appearance,aroma,taste and the soup color have the old tea quality: orange soup,sweet and mellow taste,and rich aroma.However,It also can be seen,of all the samples,the 2008's Ann tea got the top score.Compared with the 2007's tea and the 2006's which stored for longer yeas,the appearance,aroma and taste of the 2008's is slightly better than the 2007's and the 2006's.It indicate that storage environment is also an important factor for the tea quality.3.In the experiment,two phenolic compounds were extracted and isolated from Ann tea.which are the GA and EGCG(Epigallocatechin Gallate).