Abstract:
Polyphenol composition in black tea plays an important role in antioxidant activity,
sensory quality, and health benefits. Understanding regional variations in polyphenol
content is important for tea quality assessment and origin authentication. This study
aimed to compare the total polyphenol content (TPC) and dry matter content of Broken
Orange Pekoe Fannings (BOPF) black tea from selected Sri Lankan tea-growing regions
and evaluate their potential for regional differentiation. BOPF was selected because its
fine particle size facilitates efficient extraction and provides reliable analytical
measurements. It is also one of the most widely used grades in tea bags and commercial
blends. Tea samples were collected from five major tea-growing regions of Sri Lanka:
Sabaragamuwa, Dimbula, Ruhuna, Udu Pussellawa, and Uva. Ten factory-grade
samples were obtained from each region to ensure representative sampling. Dry
matter content was determined according to ISO 1572 and used to express results on
a dry weight basis, while TPC was determined using the Folin–Ciocalteu colorimetric
method according to ISO 14502-1:2005(E). Absorbance was measured at 765 nm using
a UV–Visible spectrophotometer. All analyses were performed in triplicate, and
statistical evaluation was conducted using one-way analysis of variance (ANOVA). The
mean (±SD) TPC values ranged from 15.38 ± 1.36 %DW in Uva to 24.31 ± 1.98 %DW in
Ruhuna. Dry matter content ranged from 90.92 ± 0.51 % in Dimbula to 94.60 ± 0.70 %
in Sabaragamuwa. ANOVA revealed significant regional differences in both TPC (F =
12.11, p < 0.001) and dry matter content (F = 20.61, p < 0.001). These variations may
be influenced by regional agro-climatic conditions, including elevation, temperature,
rainfall, and soil characteristics, as well as differences in factory-level processing
practices. The findings demonstrate that TPC and dry matter profiles provide regionspecific
biochemical information that may support future studies on tea origin
verification, quality assessment, and future analytical approaches for regional
classification of Sri Lankan black tea.
