Abstract
BackgroundTea is the most consumed beverage in the world which is second only to water. Tea contains a broad spectrum of active ingredients which are responsible for its health benefits. The composition of constituents extracted to the tea brew depends on the method of preparation for its consumption. The objective of this study was to investigate the extraction kinetics of phenolic compounds, gallic acid, caffeine and catechins and the variation of antioxidant activity with time after tea brew is made.MethodsCTC (Crush, Tear, Curl) tea manufactured in Sri Lanka was used in this study. Tea brew was prepared according to the traditional method by adding boiling water to tea leaves. The samples were collected at different time intervals. Total phenolic and flavonoid contents were determined using Folin ciocalteu and aluminium chloride methods respectively. Gallic acid, caffeine, epicatechin, epigallocatechin gallate were quantified by HPLC/UV method. Antioxidant activity was evaluated by DPPH radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays.ResultsGallic acid, caffeine and catechins were extracted within a very short period. The maximum extractable polyphenols and flavanoids were achieved at 6–8 min after the tea brew is prepared. Polyphenols, flavanoids and epigallocatechin gallate showed a significant correlation (p < 0.001) with the antioxidant activity of tea.ConclusionThe optimum time needed to release tea constituents from CTC tea leaves is 2–8 min after tea is made.
Highlights
Tea is the most consumed beverage in the world which is second only to water
This study aims to evaluate the kinetics of solid liquid extraction of polyphenols, flavonoids, gallic acid, caffeine, epicatechin and epigallocatechin gallate in tea infusion made with CTC tea
England). β-hydroxyethyltheophy lline, caffeine, gallic acid, epicatechin, (−)-epigallocatechin gallate, Folin Ciocalteu reagent, 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and aluminium chloride were purchased from Sigma Chemicals, USA
Summary
Tea is the most consumed beverage in the world which is second only to water. Tea contains a broad spectrum of active ingredients which are responsible for its health benefits. The objective of this study was to investigate the extraction kinetics of phenolic compounds, gallic acid, caffeine and catechins and the variation of antioxidant activity with time after tea brew is made. Excessive in vivo production of reactive oxygen species (ROS) leads to oxidative damage in lipids, protein and DNA. An increasing number of scientific publications suggest that certain edible plants may offer protection or treatment against some chronic diseases. These beneficial effects can be attributed to their antioxidant. The production of black tea involves allowing tea leaves to wither where the moisture content of the leaves is reduced followed by rolling and crushing to initiate fermentation [6]
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