Tea constituents and export standards of Sri Lanka teas

Recently UNCTAD/GATT discussed the concept of minimum export standards for tradeable teas.' Since earlier work, .on Malawi teas (CTC manufactured, 'plain - teas') showed that a good .correlation was obtainable between the theaflavin (TF) fraction of. black tea and market valuation, there was a proposal that TF content be included as a minimum export standard for all teas. The theaflavin fraction of black tea is. believed to make important contributions 'to the colour and' mouthfeel' properties of its infusion. But TF as a criterion of quality/ valuation may not be strictly correct for orthodox-manufactured Sri Lanka teas, because in these' superior - teas., TF is only one of the many constituents contributing to valuation. An investigation was therefore undertaken to evaluate TF as an index of market price. The relationship of other constituents was also examined. . In attempting to relate TF content to market price, consideration has to be given to the fact that because of market trends,- the value in monetary terms given to TF (or any other '. biochemical component) varies from sale to sale. This was overcome by taking a large range of teas .(24 samples) of one. grade sold;at the Colombo auctions in one day by one broker. The teas were assayed for their th'eaflavin content, total colour and soluble solid content. The results were collected over 16 sales, and the data were used to examine in Sri Lanka teas, the influence of the different constituents on market valuation. None of the tea constituents examined, namely theaflavins, total colour or solids were correlated to market price, on any of the 16 sales.