Akademik Veri Yönetim Sistemi
1. INTERNATIONAL VARNA SCIENTIFIC RESEARCH AND INNOVATION CONGRESS, Varna, Bulgaristan, 7 - 08 Mayıs 2026, ss.190-191, (Özet Bildiri)
Gallic acid, caffeine, and catechin derivatives are among the most critical compounds influencing both the antioxidant potential and sensory attributes of tea. The present study aimed to determine the levels of these constituents in green and black tea samples, as well as their respective extracts, sourced from the Çaykur Cumhuriyet Tea Factory in Rize Province. All analyses were conducted using the HPLC method in accordance with ISO 14502:2 standard guidelines, while extraction and analytical procedures were carried out at the Chromatography Laboratory and Extraction Unit of the Çaykur Atatürk Tea and Horticultural Research Institute. The analytical results indicated that the dry matter (dm) contents of gallic acid (GA), caffeine (CA), and total catechins (C) in green tea were 0.02%, 2.43%, and 13.62%, respectively. Black tea, by comparison, yielded values of 0.09%, 2.23%, and 0.14% for the same parameters. With respect to the extracts, green tea demonstrated GA (dm) at 0.14%, CA at 5.75%, and C at 31.51%, whereas the corresponding values in black tea extract were 0.82%, 14.97%, and 1.26% for GA, CA, and C, respectively. A comparative evaluation between the two tea types revealed that the GA content in black tea by 4.5-fold, while the C content experienced a substantial reduction of 97.2-fold. Similarly, in the extracted fractions, GA and CA levels were 5.8 and 2.6 times greater in black tea than in green tea, whereas the C concentration was approximately 25 times lower. Overall, our findings confirm that the contents of GA, CA, and total catechins are considerably affected by both the category of tea and the manufacturing processes employed. Keywords: Tea, Camellia sinensis, gallic acid, caffeine, catechin.