A Multi-Analytical Exploration of Flavored Black Teas: Profiling Volatile Compounds, Caffeine Content, and Biological Effects

Abstract

This study aims at investigating the phytochemistry and biological effects of three different flavored black teas from Sweden. Analyses were conducted using gas and liquid chromatography. The major volatile compounds of all the tea samples were found to be linalyl acetate and α-terpineol. HPLC results indicated caffeine levels of 1.08%, 1.46%, and 1.18% in samples Ht1, Ht2, and Ht3, respectively. Ht1 exhibited the highest antioxidant activity, particularly in DPPH^· and ABTS⁺ radical scavenging capacities (0.15 and 0.21 mgTE/g, respectively). Additionally, Ht1 also showed higher antioxidant activity than the other samples in both CUPRAC and FRAP tests. Metal chelation capacity was highest in Ht3, suggesting significant chelation potential due to nonphenolic components. Ht1 showed strong inhibitory activity against acetylcholinesterase (1.21 mg GALAE/g), butyrylcholinesterase (3.48 mg GALAE/g), and tyrosinase (1.47 mg KAE/g) enzymes. It highlights valuable insights into how different flavor additives may influence the health benefits of tea.

Keywords: antioxidant activity; caffeine content; enzyme inhibition; flavored black tea; volatile compounds.

FIGURE 1

Venn diagram of recognized compound numbers in the first group of tea extracts.

FIGURE 2

Dendrogram obtained by HCA based on Euclidean distances between groups of the major components of tea extracts.

FIGURE 3

HPLC chromatogram of caffeine (Rt: 9.887).

FIGURE 4

HPLC chromatogram of Ht1 (1. Caffeine Rt: 8.628).

FIGURE 5

HPLC chromatogram of HT2 (1. Caffeine Rt: 8.236).

FIGURE 6

HPLC chromatogram of sample Ht3 (1. Caffeine Rt: 9.002).