Article ID: FSTR-D-24-00220
Because polyphenols are bioactive components in foods, an accurate and simple method for their determination is required. Currently, the Folin-Ciocalteu and iron tartrate methods are utilized for analyzing the total polyphenol content (TPC) in black tea. However, there are no scientifically based comparative data for these colorimetric methods. Therefore, in this study, an appropriate method for analyzing the TPC in black tea was proposed. Comparison of the efficacy of these colorimetric methods for the analysis of fresh and fermented black tea leaf samples, including quantitative HPLC data, showed that both colorimetric methods provided characteristic data depending on the degree of tea-leaf fermentation. The iron tartrate method was affected by the type of polyphenols in tea leaves, whereas in the Folin-Ciocalteu method, the reducing power of the polyphenols directly affected the total polyphenol equivalents. Both colorimetric methods were effective for analysis of the TPC in black tea leaves.
