Analysis of caffeine and flavan-3-ol composition in the fresh leaf of Camellia sinesis for predicting the quality of the black tea produced in Central and Southern Africa Louwrance P Wright, 1 Nicholas IK Mphangwe, 2 Hastings E Nyirenda 2 and Zeno Apostolides 1 * 1 Department of Biochemistry, University of Pretoria, Pretoria 0002, Republic of South Africa 2 Tea Research Foundation (Central Africa), PO Box 51, Mulanje, Malawi Abstract: A parameter of fresh tea leaf that correlates with black tea quality is highly desired. Twenty good and 20 poor quality tea clones were selected from the breeding programme at the Tea Research Foundation (Central Africa) (TRF(CA)). The ¯avan-3-ol pro®le of fresh tea leaves was analysed by capillary electrophoresis while total thea¯avin (TF) content was determined in the black tea manufactured from the same leaves for each clone. The above parameters were correlated with total scores and valuation from two tea tasters with regression analysis. The signi®cance of the differences between the 20 good and 20 poor quality tea clones was determined with the Student's t-test. The total TF content of the black tea correlated (r = 0.63, P =0.0001) well with the value of the tea. Of all the parameters determined in the fresh leaves, the highest correlation was obtained with ()-epicatechin (EC) (r = 0.65, P = 0.0001). This may facilitate early selection of good quality TRF(CA) clones in the future. # 2000 Society of Chemical Industry Keywords: black tea; Camellia sinensis; quality; catechins; polyphenols; ¯avan-3-ol; caffeine; southern Africa; thea¯avin INTRODUCTION The quality of the manufactured black tea produced in Southern Africa, based on organoleptic evaluation, has been medium by international standards. This prompted the Tea Research Foundation (Central Africa) TRF(CA) to adopt a long-term tea plant improvement programme in 1956 with the emphasis on quality. 1 Evaluation of new clones is a long term process requiring 15 years before release. The aim of this work was to develop a method for predicting quality early in this programme. Flavan-3-ols synthesised in tea leaves are the most important non-volatile constitutent substrates of black tea. Derivatives of the ¯avan-3-ols provide the charac- teristic taste and visual appeal to the liquor. 2 Six major ¯avan-3-ols occur in tea; ()-catechin (C), ()- gallocatechin (GC), ()-epicatechin (EC), ()-epi- gallocatechin (EGC), ()-epicatechin-3-gallate (ECg) and ()-epigallocatechin-3-gallate (EGCg). In black tea manufacture, the leaves are macerated to break down sub-cellular compartments. This allows cyto- plasmic polyphenol oxidase (PPO) (EC 1.10.3.1) to oxidise the vacuolar ¯avan-3-ols. The main conse- quence of this aerobic fermentation process is the polymerisation of the ¯avan-3-ol monomers to form thearubigins (TR) and thea¯avins (TF). Various biochemical methods exist to assess quality in black tea, the most important being the analysis of thearubigins (TR) and thea¯avins (TF). 3 The chemi- cal nature of the TR is still poorly understood, making them dif®cult to analyse. 4 Thea¯avins, on the other hand, are well characterised. Total thea¯avins were shown to be closely related with quality and market value for Central African seedling black teas. 5,6 This relationship was less apparent for Kenyan black teas. 7,8 Owuor and Obanda 9 and Owuor et al 10 showed that thea¯avin digallate equivalents were more important in predicting quality in Kenyan black teas. A major disadvantage of methods evaluating quality based on TR and TF content is the need for samples of manufactured black tea. Suf®cient amounts of tea leaves are necessary before a representative black tea sample of a clone can be prepared. As many as 6 years can pass before new tea clones in a breeding (Received 4 April 2000; accepted 12 May 2000) * Correspondence to: Zeno Apostolides, Department of Biochemistry, University of Pretoria, Pretoria 0002, Republic of South Africa E-mail: zeno.apostolides@bioagric.up.ac.za Contract/grant sponsor: Tea Council of Southern Africa Contract/grant sponsor: Tea Research Foundation of Central Africa Contract/grant sponsor: University of Pretoria # 2000 Society of Chemical Industry. J Sci Food Agric 0022±5142/2000/$30.00 1823 Journal of the Science of Food and Agriculture J Sci Food Agric 80:1823±1830 (online: 2000)