A comparison of the antioxidant activity of Turkish Black Tea at various processing stages

Objective: Türkiye is a country where many plants can grow due to its location and climate diversity. Rize, located in the Black Sea region, stands out notably in tea cultivation due to high rainfall and humidity. In recent years, studies in this field have acquired momentum because of interest in natural antioxidants. In this study, the antioxidant properties of the different processing stages of black tea grown in Rize were comparatively examined. Methods: This study presents the best combinations of stirring time and solvent to obtain extracts from tea samples in the most efficient way. Five methods were used for the measurement of antioxidant activity, which are as follows: Cupric ion reducing antioxidant capacity (CUPRAC) method, Ferric reducing antioxidant potential (FRAP) method, DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity method, Ferrous ion chelating (FIC) method, and total phenolic content (TPC) method. Results: The results obtained from CUPRAC, DPPH, and TPC methods strongly support each other. The other two methods also gave similar results within themselves. When all methods were examined, it was observed that the last stage of the black tea was the sample with the highest antioxidant properties, while the first stage was the sample with the least antioxidant properties. Conclusion: The experimental study points out that black tea consumption is beneficial because it helps the body to get natural antioxidants.