VARIATION IN CATECHIN COMPOSITION OF POPULARLY CULTIVATED TEA CLONES IN EAST AFRICA (KENYA)

Abstract

Tea polyphenols and catechins have gained prominence in determination of tea quality. Tea leaves contain largeamounts of catechins and their derivatives and these have shown positive effects on human health. Anexperiment was carried out to determine the level of catechins and polyphenols in 20 new clones found in twodistinct tea growing areas. The trial comprising twenty clones was established in two distinct sites in Kenya usingrandomized complete block design with three replicates and consisted of 10 popular cultivars widely cultivated inthe Lake Victoria Basin and additional 10 newly improved clones. Tea leaf samples were collected across twoseasons; dry and wet seasons. Tea quality parameters entailing catechins, caffeine and total polyphenols weregenerated for the 20 clones across the two seasons and sites. The ISO 14502-1 and ISO 14502-1:2005 procedureswere used for polyphenol and catechin analyses, respectively. The ANOVA results generated indicated that thelevel of catechins and polyphenols in tea clones were significantly different (p<0.05) and varietal dependent.Generally, the Assam varieties had higher levels of catechins and polyphenols than the Chinary and Cambodvarieties, indicating why they are popularly cultivated in the East African region and whose tea quality is highlyregarded. Furthermore, the results from principle component analysis (PCA) grouped the clones into three majorclusters with one comprising of high quality assam varieties, a mixture of moderate quality Assam, Cambod andChinary varieties and low catechin content Assam anthocyanin-rich variety. It is concluded that the level ofcatechins in tea plants are varietal dependent, although environmental stress has effects on the synthesis offlavanoids. The results demonstrated that the differences in the accumulation of catechins among the tea clonescould be important for the discrimination of clonal diversity.