Abstract:

A model system consisting of tea polyphenols and caffeine was set up for studying the formation mechanism of
green tea cream. The transmittance, particle size, amount of tea cream, caffeine and catechins contents of the solution were
investigated to study the effects of different concentrations of polyphenols and caffeine compounds on the formation of tea
cream. The results showed that the transmittance of the solution was decreased from 95.5% to 24.7%, the particle size was
increased from 198 to 475 nm and the amount of precipitate was increased from 8 to 244 mg/L with increasing addition of
polyphenols and caffeine. These changing trends were more pronounced with increasing concentration of one of the two
components at a constant level of the other. High performance liquid chromatography analysis of the contents of caffeine and
catechins showed that caffeine and EGCG were the main compounds of tea cream. Based on our results, green tea infusion was relatively
more stable when polyphenols concentration was lower than 1 200 mg/L and caffeine concentration lower than 200 mg/L.

Key words: tea polyphenols, caffeine, tea cream, concentration