Effects of Theaflavin and Thearubigin on the Color of Black Tea Infusion Measured by the Hunter Color Meter

The transmission colors of black tea infusion, the theaflavin fraction and the thearubigin fraction extracted from black tea infusion were measured by the Hunter color meter. The theaflavin and the thearubigin contents in black tea infusion were determined by the Roberts' method.The Hunter L, a, and b values of black tea infusions showed highly significant correlations to those of the thearubigin fractions extracted from black teas, and rather lower correlations to those of the theaflavin fractions.The theafiavin contents in black tea infusions did not have high correlations to the Hunter values of black tea infusions, and the thearubigin contents had rather higher correlations. From these results, it was recognized that the color of black tea infusion was effected by the color of the thearubigin fraction, which has highly relation to reddish color of black tea infusion, and the theaflaviln fraction did not have significant relation to the color of black tea infusion determined by the Hunter color meter.There were highly correlations between the theaflavin contents and the Hunter values of the theaflavin fractions extracted from black tea infusions. But there were rather lower corelations between the thearubigin fractions and the Hunter a and b values of the thearubigin fractions and there was only corelation between the formers and the Hunter L values.