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Description
The chemical composition of tea, especially its dry matter content, caffeine, and polyphenols, has a significant impact on its quality. The purpose of this study was to examine the dry matter content, caffeine concentration, and total polyphenol content (TPC) of specific black tea grades that were gathered from two main Sri Lankan tea-growing regions: Ruhuna (low-grown) and Dimbula (high-grown). Standard ISO techniques were used to analyze four tea grades: BOP, OP, Dust, and PF1. The Folin–Ciocalteu method (ISO 14502-1) was used to test total polyphenols, and UV–Visible spectrophotometry was used to measure caffeine levels after tea infusions were prepared in accordance with ISO 3103. By oven-drying the samples at about 105 °C until a consistent weight was obtained, the dry matter content was measured. Significant geographical and grade-dependent differences were evident in the results. In contrast with the well-known briskness of high-grown teas, Dimbula BOP had the greatest polyphenol concentration (24.55 ± 1.81% DW). Some low-grown samples had lower TPC; Ruhuna OP had 18.31 ± 1.30% DW. Ruhuna PF1 had the highest caffeine concentration (879.39 ± 39.54 mg CAE/L), whereas Ruhuna Dust had the lowest (504.11 ± 6.51 mg CAE/L). The dry matter content showed consistent processing conditions among samples, ranging from 91.65 ± 0.79% to 96.56 ± 0.95%.These results clearly show that high-grown and low-grown teas have very different chemical compositions. These differences are extremely useful for creating analytical tools, particularly sensor-based devices like an electronic tongue (E-tongue) that can distinguish between different types of tea based on geographic location. Strong identifiers that may be incorporated into equipment calibration and classification models to assist enhanced tea authenticity and quality control are the chemical variations found in this study.
Keywords: Black tea, Caffeine content, Total Polyphenol content, regional variation, UV-Vis spectrophotometry
