Effects of Plucking Time and Oxidation of Green Leaf on Quality Parameters of Black Tea

To study the effects of plucking time and fermentation of green leaf on quality parameters of black tea an experiment was conducted at Tea Research Foundation of Lahijan in 2004 using two different varieties. Two varieties (Var. No. 100 and Chinese Natural Hybrid) with different time of plucking and five different time of fermentation, i.e. 30, 60, 90, 120 and 150 minutes, were considered in the experiment. Percentage of theaflavins, thearubigins, total color, brightness, and tannins was measured as quality parameters. The results showed that in spite of difference between varieties, changing climates at different plucking time and fermentation time, also affected the amounts of theaflavins, thearubigins, total color, brightness, tannins and caffeine. Interaction of var × plucking time × fermentation time was significant with respect to black tea. Therefore, each variety in specific time of plucking and fermentation, will provide a best quality of black tea.