Antioxidant capacity and major polyphenol composition of teas as affected by geographical location, plantation elevation and leaf grade

- Polyphenol contents in teas are significantly affected by plantation location.
- Black tea from low elevation has >20% polyphenols than higher elevation.
- Small leaves have up to 15% more polyphenols than lager leaves.
- Leaf grade has an effect on total catechin content and antioxidant capacity.

Tea polyphenols have been a topic of discussion due to their health benefits. Nevertheless, detailed studies on the antioxidant capacity and polyphenol contents of teas in relation to factors including geographical locations, plantation elevations and leaf grades have been limited. In this study, 53 tea samples were analysed to determine the individual and total catechin and theaflavin contents by HPLC and the total antioxidant capacity by Oxygen Radical Absorbance Capacity (ORAC) methods. Results show that the polyphenol (catechins and theaflavins) contents were significantly influenced by plantation location. Black tea from low plantation elevation contained 22-28% more polyphenols than those from high elevation. Small tea leaves had up to 15% more polyphenols than larger leaves from similar elevation. The results were further confirmed by Principal Composition Analysis (PCA), which grouped the black and green tea samples into 3 different clusters, respectively.