| Aroma is one of the most important essentials of tea quality.This paper studied the equilibrium constant of tea caffein,polyphenol,amino acid,and the volatile constituents of decaffeined black tea,decaffeined green tea and Dongting Biluochun. Then revealed the characteristics of the aroma of the teas.Through experiment,we found that the most dissolve equilibrium constant of each biological constituents were at the range of 0.1—0.8kg/dm3.The amino acid dissolve equilibrium constant of the fermented tea was higher than that of the unfermented tea, and the broken tea is lower than that of the unbroken tea.The amino acid of pan-fired tea was different from caffein and polyphenol,it was the higher of the concentration, the higher of the dissolve constant.For some extent,ferment was good to the dissolve of caffein in tea,but the constituent of full fermented was lower than that of the part fermented tea.We analyzed the flavor constituents of pan-fired tea material,green tea oil and the deacaffeined green tea.Due to the characteristic of the supercritical CO2,some special constituents were extracted,the variety of the flavor constituents decreased distinctively and the proportion of the constituents changed a lot.Some low boiling point constituents of C5-C6 and the high boiling point constituents like 5,6-epoxy-β-ionone,nerolidol,6,10,14-trimethyI-pentadecanone which existed in the green tea material but weren't detected in the decaffeined tea.The flavor constituents in the green tea oil were different with that in the green tea material,some constituents were the same and some like(+)-β-cedrene,α-ionone,2-methyl-naphthalene weren't detected in the tea material.Perhaps the constituents also existed in the tea material,but the concentration was too low to be detected by the apparatus.The other reason is they were the constituents of the ester broke down.Compare the biology constituents in the material,the content of polyphenol and amino acid in the decaffeined tea were a little higher than that in the green tea material,yet the caffein decreased from 2.90%to 0.77% The broken black tea material,black tea oil and the decaffeined black tea were analyzed.The mass of the flavor constituents was 46.1%higher in the tea oil than that in the black tea material.The variety of the flavor constituents changed,some constituents were detected in the black tea oil but not in the black tea material.The proportion of the constituents also changed.The variety of the flavor constituents in the decaffeined tea is the similar of the black tea oil,yet the content of each constituent decreased,and the total mass of the flavor constituents decreased 78.89%.After the tea oil was extracted by ethanol,the remainder was the white.Through the IR analysis,we found that it was the mixture of the alphatic and alphatic esters. The melting point of the compounds was 75-78℃,which was as the same of the report of the plant wax.The compounds separated into two different yellow dot in the TLC experiment,and it indicate that there were two different variety of compounds.The Dongting Biluochun is one of famous tea in China and it has the unique flavor.Nonanal is the highest content of the new made biluochun and it was one of the characteristic flavor constituent which is different with other teas.We also studied the old made biluochun,finding that the nonanal decreased a lot,yet the benzaldehyde increased a lot and which became the highest conten constituent.The proportion of nonanal and benzaldehyde was 22.89 in the new made tea but 0.097 in the old tea.So we could make the proportion as a standard to judge the verdure degree of Dongting Biluochun.We compared the flavor constituents of the Dongting Billuochun and Longjing, finding that they have some similar because they are all pan-fired tea,both of them have the constituents of pyrazines and pyrroles,and the high content of linalool and geraniol.Also they had some different,the nonanal is higher in the Biluochun than that in Longing.
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