Optimization Of Brewing, Processing Conditions And Their Effects On The Chemical And Sensory Quality Of Purple-leafed Kenyan Tea

The Tea Research Institute (TRI) developed TRFK 306 tea clone which is rich in anthocyanin as a strategy to diversify Kenyan teas. TRFK 6/8 was used as a control in the study being a standard clone used at the TRI. TRFK 306 can be utilized non-processed but there is no well researched, documented data on the best brewing conditions. Consumers add edible acids to its brew to improve the colour and taste but information on the acid effect is scanty. Information on the quality of products manufactured in various ways is equally scanty. Completely randomized block design replicated three times was adopted. Fresh TRFK 306 tea leaves were brewed using time temperature combinations of 70 0C and 92  0C timed at 5, 10 and 15 minutes prior to analysing for total anthocyanins and antioxidant activity. Citric acid concentration of 0.1 %, 0.2 %, 0.3 %, 0.4 % and 0.5 % were used to check their effect on total anthocyanins .antioxidant activity and sensory quality. Five- point hedonic scale was used in the sensory evaluation. Non-aerated and aerated orthodox and Crush, Tear and Curl (CTC) teas were processed at different withering times with an interval of 5 hours starting from 0 up to 20 hours. Aeration duration was varied at an interval of 30 minutes, from 30, to 90 minutes. Tea quality parameters were assayed using the Flavognost method, Roberts method, High Performance Liquid Chromatography (HPLC) and UV spectrophotometer.