Theaflavins account for between 0.3 and 1.8% of the dry weight of black tea and between 1 and 6% of the solid in tea liquor. Various theaflavins and their respective precursors are as follows: theaflavin (EC+ECG), theaflavin-3-gallate (EC+EGCG), teaflavin-3’-gallate (ECG+EGC), theflavin-3,3’-digallate (ECG+EGCG) and isotheaflavin (EC+GC). Other theaflavins, such as theaflavates A and B, theaflavic acids, are rarely characterized.
Under slightly acidic conditions (pH 6.5), theaflavins are stable, but they degrade slowly at pH 7.0 and 7.5 and rapidly at pH 9.0.
The amount of theaflavins is quoted to be closely related to the commercial value of black tea. To separate theaflavins, black tea is extracted with water then washed with solvents to remove the impurities.
Theaflavins are bright red pigments giving the tea liquor the characteristics describe by tasters as ‘brightness’ and ‘briskness’.
Theaflavins in tea
