Assessing biochemical changes during standardization of fermentation time and temperature for manufacturing quality black tea.

In black tea manufacturing, one of the most important steps is fermentation which influences the quality of tea. The macerated tea leaves were fermented at various temperatures (20, 25, 30, 35 °C) for different duration. Changes in polyphenoloxidase and peroxidase activities, depletion patterns of individual catechins, differences in individual theaflavin levels and formation of thearubigins were measured in leaves during fermentation.