Caffeine and total polyphenol contents of market tea cultivated and processed in Bangladesh.

OBJECTIVE: The aim of this study was to determine the contents of caffeine and total polyphenol in six brands of market tea cultivated and processed in Bangladesh.

METHODS: Caffeine and polyphenol contents were determined by solvent extraction (AACC) and the International Organisation for Standardisation Method (ISO) 14502-1 respectively.

RESULTS: Caffeine contents of the different tea samples ranged between 0.99 +/- 0.17% to 2.08 +/- 0.16% (g/100g materials), while that of total polyphenol was from 36.90 +/- 1.39% to 17.29 +/- 2.30% of gallic acid equivalents (GAE). The order of caffeine concentration in tea samples was found as follows: Organic Black Tea > Taaza Tea > Organic Green Tea > Magnolia Tea > Organic Zinger Tea > Organic Tulsi Tea. The polyphenol concentration in the tea samples was highest in Organic Green Tea followed by Taaza Tea and the rest as follows: Magnolia Tea > Organic Black Tea > Organic Zinger Tea > Organic Tulsi Tea. An indicative difference in amounts of caffeine and polyphenols for different tea brand samples is seen in this study.

CONCLUSION: This systematic screening provides information to producers as well as consumers on the quantities of caffeine and polyphenols in commercial tea available in the markets of Bangladesh.