Abstract:
Tea is one of the most popular beverages in the world, is an infusion of the leaves of the tea
plant, Camellia sinensis which is under the Theaceae family and the Camellia species (Camellia
sinensis). The main types of tea are green tea, oolong tea, white tea and black tea. Among the
four types, black tea is the most commonly consumed in the world. Therefore, the aim of this
study was to determine total phenol content from some commercially available Ethiopian black
tea. To find the best extraction condition, heat extractions were conducted at different solvent,
temperature and time. Finally, the tea samples were analyzed for phenol content with Uv/Vis
Spectroscopy at 760 nm. Under optimum conditions of 80% ethanol solvent ratio, 80°C
temperature and extraction time of 15 minutes, the TPC found in Gumaro, Wush-wush and Back
lion tea were 28.5 ± 0.96 mg GAE/g, 26.5 ± 0.82 mg GAE/g and 23 ± 0.24 mg GAE/g,
respectively. From the three Ethiopian black teas Gumaro black tea have the highest total
phenol content and black lion have the lowest phenolic content. The detection limit (LOD) and
quantification limit (LOQ) were 1.3 and 3.8 mg GAE/g, receptively. Even if the samples were
belong to the same black tea type, the level of TPC in the three tea type were significantly
different (p<0.05) at 95% confidence interval. The possible reason for this difference total
phenolic content could be different ways of tea cultivation, period of harvesting, different
processing procedure, fermentation time and other process.
