Studies On Phenolic Components And Unique Aroma Components Of Different Dark Teas

Dark tea is the unique types of Chinese tea,they are fermented by microorganisms.Fu tea and Pu'er tea are two well-known dark teas.Their main strains of the fermentation process are Aspergillus niger and Eurotium cristatum.In the study,we analyzed the polyphenols components of different teas,and established the fingerprints of Jingwei Fu tea.We also analyzed the fragrance components of different dark teas.By the experiment,we obtained the following conclusions:(1)Compared with the non-fermented tea,the fermented tea has higher level of gallic acid.In all kinds of dark teas,the contents of catechin,gallic acid,epigallocatechin,epigallocatechin gallate,epicatechin,gallocatechin gallate,epicatechin gallate and caffeine are higher in Jingwei Fu tea,especially the epigallocatechin and epigallocatechin gallate.(2)Set up a fingerprint of Jingwei Fu tea.The similarities of different Jingwei Fu tea are 0.81-0.94.(3)We determined the total polyphenols and total flavonoids of 26 different batches of Jingwei Fu tea.There was no significant difference between the four different series of Jingwei Fu tea.(4)GC-MS analysis showed that the dark tea produced more new aroma compounds than the green tea,and different tea has its main aroma compounds and its own unique aroma components.(5)The samples fermented by two strains have less species of aroma compounds than the finished tea.The samples fermented by Aspergillus niger did not produce methoxbenzene,they are the main aroma components of Pu'er tea,they began to smell unpleasant when fermented to 72h.The samples fermented by Eurotium cristatum produced new aroma compounds like Geraniol,cis-Thujopsene and Styrene.All of the tea leaves are covered with "Golden Flower" when fermented to 96h,and began to produce the unique aroma of Fu tea.