Influence of clone and duration of withering on quality of black tea (Camellia Sinensis (L).O Kuntz)

Abstract

At Wush wush five commercial Camellia sinensis var.assamica of tea clones are under production. Withering is the first processing step in the factory and is a process in which freshly plucked leaf is conditioned physically, as well as, chemically for subsequent processing stages. Indeed, withering is one of the most important tae production process steps and can be said to constitute the foundation for achieving quality in tea manufacture. This most important processing (withering) step is being done for uniform duration (18h) irrespective of the type of clone to be processed. Furthermore, there was no research done so far to optimize withering duration for these five different types of clones grown under Wush wush tea plantation and hence only subjective judgment is used by factory cup tasters to determine the optimum withering duration. Therefore, this study was initiated with the objective of investigating the influence of clone and duration of withering on black tea quality. The research was conducted at Wush wush and Jimma southern part of Ethiopia in the year 2011\12. The experiment consisted of five clones (11\4, BB\35, 11\56, 6\8 and 12\38) and five duration of withering laid out in 5x5 factorial arrangement in Randomize Complete Block Design (RCBD) with three replications. Data were first checked for all assumptions and subjected to the analysis of Variance (ANOVA) by using SAS version 9.2. Software and significant means separated using least significant difference (LSD) test. The result of the study showed that interaction of clone and duration of withering had significantly influenced the theaflavin(TF), thearubgine(TR), brightness(BR), thickness(TH), briskness(BS), strength (ST) and color (CL)and the highest (3.2) TF was obtained with 17h duration of clone 6\8 and lowest with 20h for clone 11\56 (1.8), while the highest (19.2%) TR at was recorded with 19h withering of clone 12\38 and lowest with 16h withering of clone 6\8 (11.1%). The maximum value (26.8) for BR was observed with 16h withering of clone 11\4 and the minimum (15.3) was noted from clone 11\56 which was withered for 20h. On the other hand, TH was maximum (2.67) when withering duration was between 16 and18h and lowest (1.3) at 20hr. The highest (2.67) BRS developed from 16hrs and 18hrs withering of clone 11\4 and 11\56 while the lowest (1.67) was from 20h withering in clone 6\8. The strength of the tea was at its maximum (4) ST when the withering duration was adjusted to 18h in clone 6\8 and lowest(2) in clone 6\8 and 11\56 withered for 16 and 20h. Moreover, the highest value (2.67) for CL was registered when tea leaves were withered for 20h in clone 6\8 and 12\38 and lowest (1.3) in clone 11\56 withered for 16h and 20hrs. It was generally observed that almost all clones gave good quality when the withering duration was fixed between 16 and 18 hours and both chemical and sensory analysis result showed that the optimum withering time for clone 11\4 and 12\38 are16h and BB\35 and 6\8 are show good quality at 17 hour and 11\56 18h. Therefore by considering these optimum withering hours for the different clones we can save time many man power and most important thing improving the quality of black tea.