Studies on the Colored Components in Black Tea Infusion

Three components (theaflavin, theaflavin-monogallate and theaflavin-digallate) of theaflavin compounds in black tea infusion were separated by column chromatography using Sephadex LH-20.Three compounds were resolved in the order of theaflavin, theaflavin-monogallate and theaflavindigallate from Sephadex LH-20 column with gradient elution of aqueous acetone from 40 to 80%.The contents of three theaflavin in black tea infusion were determined colorimetrically from the molar extinction coefficient of authentic theaflavin at 460nm after the separation of each components by Sephadex LH-20 column chromatography.From the results of the determination of theaflavins in several black tea infusions, it was recognized that the content rates of theaflavin, theaflavin-monogallate and theaflavin-digallate in total theaflavin were about 35%, 46% and 19%, respectively.Among these three theaflavin compounds, the contents of theaflavin and theaflavin-monogallate showed the high positive coefficients of corrolation for the color quality of black tea infusion. However, theaflavin-digallate did not show the significant correlation for the color quality of black tea infusion.