The Variation Of Chemical Component During The Fermentation Procedure Of Pu'er Tea

Pu'er tea originates in Yunnan province. It uses sun dried green tea of yunnan da ye species as its raw material and processed with a special after fermentation procedure. Pu'er tea has many healthy functions. It is one of the fast growing special teas recent years and is popular among the consumers in HongKong, TanWan and Japan.The fermentation procedure of Pu'er tea is based on the chemical component of sun-dried green tea. Under the enzymatic action of extracellular enzymes and the damp and heat effect in the tea heap, teapolypheol experiences a series of complex and fierce chemical change which result in the special flavor and taste of Pu'er tea. Therefore , the formation of Pu'er tea flavor is due to the enzymatic action of micro and the damp and heat effect. A series of complex chemical change such as oxidize, polymerization, condensation, decomposition happened and certain corresponding component is formed in the tea heap. This procedure change the sun-dried green tea into Pu'er tea. During the fermentation process, the content of many component varied dramaticallyThe experiment starts from the fermentation procedure of sun-dried green tea and measures the variation tea pigments and other biochemical index including the gallic acids and gallic acid esters, we discusses the variation of tea pigment, gallic acid and their relation with the fermentation degree. The conclusion of the research are as followings:1 The fermentation procedure of Pu'er tea is based on the chemical component of sun-dried green tea. Under the enzymatic action of extracellular enzymes and the damp and heat effect in the tea heap, teapolypheol experiences a series of complex and fierce chemical change which result in the special flavor and taste of Pu'er tea.2 Violent changes happened on the chemical component during the fermentation procedure. The content of teapolyphenol, amino acid, soluble sugar, protopectin, crude fiber, TR decreased continuously. The content of caffeine, soluble pectin, TF, TB increases; the content of water extract does not change much.3 The variation of catechin component are as follows: the content of EC,EGCG,GCG,ECG,CG decreases dramatically during the fermentation procedure. the content of GC,EGC also decreases, however decrease range of different water content has much difference. The catechin content increases during the fermentation procedure.4 The optimal analytical condition for GA,PG are (0.5%)acetic acid and (80%)methanol., the ratio of mobile phase are 30:70.5 The content of GA increases at the early stage of fermentation, then it decreases gradually, the content of GA increases a little at the end of the fermentation. The content of PG increases at the early stage then decreases, the content of PG increases dramatically during the drying stage.6 The water content have much influence on the content of EGC,EC,TB and soluble sugar, the statistical result reaches significant level.7 The content of GA and catechin has some correlation, the correlation coefficient is -0.8693 and -0.8494 respectively, it could be inferred that the catechin maybe one source of the formation of GA.