Effect of drying temperature and duration on biochemical composition and quality of black tea (camellia sinensis L.) O. Kuntze at Wush Wush, south western Ethiopia

Abstract

This study evaluates the effect of different drying temperature and duration on biochemical composition and quality of black tea. In black tea processing drying is the last step and it gives quality to the brew. In Wush Wush regardless of clones, tea leaves conditions and quality of the final product; a drying temperature of 110°C for 25 min was used to dry tea leaves. Furthermore, there was little research done so far to optimize drying temperature and duration and only subjective judgment had been used by factory cup tasters to determine the optimum drying temperature and duration. Therefore, this research was conducted at Wush Wush tea plantation and JUCAVM post-harvest laboratory in the year 2012/2013 on clone 11 /4 to identify the optimum combination of drying temperature and duration using five drying temperature and three drying durations. The experiment was laid out using factorial design arranged in Randomized Complete Block Design (RCBD) in three replicates. Analysis of variance indicated that there were significant differences (p<0.05) among the treatment combinations (interaction effect) for all the traits (Total brightness, Total liquid color, Thearubigin, Aroma, Flavor, Moisture content and Leaf infusion) considered except Theaflavine whose main effect was observed to be significant. Generally it was observed that as temperature increased with duration the biochemical composition and quality of black tea were decreased. From this research to produce good quality of black tea a treatment combination of 100°C with 25 min was identified as the optimum treatment combination to be used in this production and other sites who are engaged in tea production in Ethiopia. © 2013 Asian Network for Scientific Information.