Changes in the chemical and sensory quality parameters of black tea due to variations of fermentation time and temperature

The changes in theaflavins and residual catechin compositions, thearubigins TRSI and TRSII, sensory characteristics of total colour, brightness and briskness of black tea were investigated. It was demonstrated that the degradation of individual theaflavins varied during fermentation. Decline in the levels of individual theaflavins was influenced by both duration and temperature and coincided with decline in brightness and briskness. ECG and EGCG were the main residual catechins in black tea. The formation of thearubigins TRSI and TRSII, differed in their response to fermentation duration and temperature. The effects of processing parameters, fermentation temperature and duration, on chemical quality and tea liquor sensory characteristics are discussed.