Determination of Inherent Fructose, Glucose and Sucrose Concentrations in Black Tea from Low Country Region in Sri Lanka

Tea is exclusively a natural beverage which is derived from the tender fresh harvestable shoots of the plant Camellia sinensis (L.) O. Kuntze; thus, as with all the other chemical constituents, carbohydrates in black tea are also attributed to the components in harvestable shoots. Though numerous studies have been conducted on biochemical constituents in black tea, available information on its sugar components is scarce. Thus, this study attempted to quantitatively determine carbohydrates in the forms of three major soluble sugars, fructose, glucose, and sucrose in black tea using High Performance Liquid Chromatographic (HPLC) technique. This is the first comprehensive study in Sri Lanka, on this regard, and the initial attention was paid to the low-country region, which provides a major contribution to tea production in Sri Lanka. A total number of 737 black tea samples including ten different grades from 77 tea factories was analyzed to represent nearly 21% of the total number of factories in each of the Ratnapura, Galle, Matara, and Kalutara districts. The average levels of fructose in the black tea are 6.77, 7.59, 7.15, and 7.08 mg g^-1 while the average values of glucose are 6.37, 6.27, 5.86, and 6.96 mg g^-1 and the average values of sucrose are 5.23, 6.70, 4.91 and 7.01 mg g^-1 among the selected ten different black tea grades from Ratnapura, Galle, Matara and Kalutara districts, respectively. According to the statistical analysis, for all three sugar components, the concentration values were not significantly different among the selected black tea grades while a significant difference in concentration values for all three sugar components was observed among four different regions in low country elevation.