Abstract
The presence of gallic acid and flavonoid pigments in tea leaves is already reported by many authors, but the method for estimating the substances has not been established.
When the HCl-forrpalin reagent is added to the extract of tea leaves, gallic acid and flavonoid are detected on the paper chromatogram of the filtrate of this treated solution and other phenolic compounds are not present in this solution. (Fig. 1).
So we have studied the colorimetric estimation of, gallic acid and flavonoid in tea leaves. The technique is as follows: we have added 4 cc. of saturated Na2CO3 solution and, 2 cc. of 5% phosphomolybdic acid solution to 4 cc. of the filtrate obtained by filtering the mixture consisting of equal volumes of the extract of tea laves and HCl-formalin regent, and after 15 min. determined its absorbency in a Pulf rich photometer with the filters S 72 and S 43 (Fig. 2). As the calibration, curve obeys BEER's law, we have been able to estimate gallic acid and flavonoid in tea leaves. (Fig. 3, and Table 5).
