Chemical and sensory quality evaluation of newly developed tea clones in Kenya

Abstract

A study was conducted on the newly developed purple tea clones in Kenya. Green tea quality analyses on theanine and catechins were done using HPLC, while total polyphenols were done using the Folin- Ciocalteu phenol reagent method. Sensory analysis was also done on green tea samples. Plain black tea quality parameters were determined (total theaflavins and individual theaflavins, brightness and total colour percentages, total thearubigins and fractions and total soluble solids) for all the clones and sensory evaluation was done by experienced tea tasters in three different tea Factories in Kericho County. Completely randomized design with three replications was adopted for this experiment. Data analyses were done using General Linear Model, Correlation procedures of Statistical Analysis System (SAS, version 9.1). Means were separated by Duncan Multiple Range Test at p ≤ 0.05 significant level. Clone TRFK 91/1 had the highest theanine content of 2.18 % giving it a flavoury taste. All the test clones had higher total polyphenol contents than the Japanese clone Yabukita used as a standard in green tea experiment. Most test clones had lower mean values of total catechins except for clones TRFK 73/7 and TRFK 73/4 which showed similar total catechins like the control Yabukita with 12.15 % and 12.00 %, respectively. On the plain black tea quality parameters, most test clones showed promising results except clones TRFK 73/3, TRFK 73/7 and TRFK 91/1 which showed low mean values of most black tea parameters. Clones K-Purple and TRFK 83/1 showed good quality black tea parameters. On sensory evaluation, clones 73/3, 91/1 and TRFK 91/2 had less strength and briskness but with flavour. Most test clones had thick liquors except TRFK 73/3, TRFK 83/1 and TRFK KS 1 which had lesser thickness. Most of the test clones also had bright liquors though with dull infusions because of the purple colour. It was concluded that most of the test clones can make good green tea while a few like KS 3, KS 2, 91/2, K-Purple and 14/1 can be made into black tea.