Study on Flavor Components in “Zhouning Cloud-Mist Mountain Tea” Green Tea

In this study,different varieties of "Zhouning Cloud-Mist Mountain Tea" green tea with different altitudes were analyzed by biochemical-testing methods and SPME-GC-TOF-MS. Results showed that the water extract content was 44.78%,flavonoids content was 8.14 mg·g^-1,polyphenols content was 13.66%,amino acids content was 3.01%,caffeine content was 4.93%,and the ratio of polyphenols to amino acids was 4.47. Among 172 detected aroma components,there were 51 hydrocarbons,48 esters,22 nitrogenous compounds,13 alcohols,10 ketones,9 aldehydes,8 oxygen-containing compounds,5 sulphur-containing compounds,4 other types of components,and 2 acids. Water content was abundant in samples from all altitudes with no significant difference(P>0.05),tea polyphenols and caffeine in high altitude samples were significantly lower than those in low altitude samples(P<0.01),flavonoids content was the highest in middle altitude samples,and the ratio of polyphenols to amino acids was moderate in all altitudes and varieties,while the ratio from samples in middle and high altitudes were significantly lower than that in low altitudes(P<0.01). Samples from middle and high altitudes had characteristic fruity and floral aroma component jasmone and(E)-α-farnesene,while samples from low altitudes had characteristic woody and floral aroma components phenylethyl alcohol,linalool(and its oxides)and trans-γ-caryophyllene. Oolong tea variety had a higher content of water extracts,caffeine,tea polyphenols and amino acids with characteristic floral aroma component geraniol and Linalool oxide,while "Caicha" variety had significantly higher flavonoids content with characteristic tender chestnut aroma components dimethylnona-triene,trimethyltrideca-tetraene,hexamethyl-tridecane and hexadecane. In this essay,the characteristic quality of "Zhouning Cloud-Mist Mountain Tea" and the variances of aroma and taste compounds were discussed. The result can be a reference for selecting species,promoting the conditions of cultivation,improving qualities of products and standardization.