Variation of Predominant Biochemical Components during Quality Formation of Fresh Scent-Flavor Oolong Tea

The spring shoots harvested from the buds of Tieguanyin, Huangdan, Jinguanyin and Huangguanyin (Camellia sinensis) were used as materials for the experiments, and the contents of predominant biochemical components related to tea taste quality were determined in samples prepared during the period of shoot growth and the process of fresh scent-flavor Oolong tea, which were water extracts, total polyphenols, free amino acids, water soluble sugars,etc.The results showed that the low ratio of tea polyphenols to free amino acids and high caffeine content were the primary characters of tender shoots. As grew into two to four leaves with a banjhi bud, all of the biochemical components contents declined rapidly except for the increase of water soluble sugars.These biochemical components changed more obviously during the period of shoot growth than those in the process of fresh scent-flavor Oolong tea. When given data standardization to the contents of biochemical compositions in each tea samples, the consistent visualized pattern recognition results would be obtained by either cosine similarity analysis,or nearest neighbor clusters analysis based on Euclidean distance or principal component analysis. The biochemical patterns of spring shoots varied much differently, but their WIP (Work in process) of fresh scent-flavor Oolong tea could be well classified according to tea cultivars.