Flavanol Composition and Caffeine Content of Green Leaf as Quality Potential Indicators of Kenyan Black Teas

Abstract

The Ñavanol composition and ca†eine content of green tea leaf, black tea quality parameters of theaÑavins, thearubigins, liquor brightness and total colour varied more among clones than with time of the year. In green leaf, either ([)epicatechin gallate or ([)epigallocatechin gallate was the dominant Ñavanol present. Regression analysis of tastersÏ preferences for black teas against green leaf chemical components showed positive and signiÐcant correlations for ([)epicatechin gallate (r \ 0É498, PO 0É05 for taster A; r \ 0É665, PO 0É01 for taster B, and r \ 0É678, PO 0É01 for both tastersÏ overall ranking), ([)epigallocatechin gallate (r \ 0É513, PO 0É05 for taster B; r \ 0É532, PO 0É05 for both tastersÏ overall ranking and ca†eine (r \ 0É523, PO 0É05 for taster A; r \ 0É657, PO 0É01 for taster B; and r \ 0É686, PO 0É01 for both tastersÏ overall ranking). Similar regressions against black tea theaÑavins, thearubigin content, liquor brightness and total colour were not signiÐcant. The results suggest that the green leaf chemical components, ([)epicatechin gallate, ([)epigallocatechin gallate and ca†eine could be used as quality potential indicators during clonal selection and propagation