Effect of different timing of withering on polyphenols and caffeine contents of black tea camellia sinensis L.

A study was conducted on the effect of withering time viz. 0 (fresh), 21, 22, 23, and 24 hours on moisture, polyphenol and caffeine content of tea sample collected from National Tea and High Value Crops Research Institute (NTHRI), Shinkiari, Mansehra during the months of July and August during 2013-14. Maximum average moisture contents (77.30% and 74.82%) were observed in the fresh tea leaves plucked during July and August, respectively, whereas, made tea showed the moisture contents in the range of 3 to 3.25%. Maximum polyphenol contents were observed in fresh tea leaves (19.8 % and 20.2%) during the month of July and August, however after processing, the highest polyphenol contents were observed in both months (11.41% in July and 11.4% in August) at 24 hours interval. The highest amount of theaflavin was obtained in both months July and August (1.21% and (1.23%) at 24hr interval. Maximum caffeine content (3.62% and 3.45%) in the samples collected during July and August, respectively were observed in 24 hours interval and minimum caffeine content (2.04% and 2.34%) in the 21 hours interval withered samples collected during the month of July.