The clear supernatants were anthocyanin extracts. Two solutions
were prepared, one solution (4 mL) is prepared with pH 1.0 (1.49 g/
100 mL potassium chloride water buffer, acidified with HCl) of
buffer, and the other solution (4 mL) is prepared with pH 4.5
(1.64 g/100 mL sodium acetate water buffer, acidified with HCl) of
buffer. Samples were diluted to 10 mL of final volume. The absorbance
of each sample was measured both at 520 nm and 700 nm.
Total anthocyanins was expressed as cyanidin-3-glucoside equivalent
(C3GE), and calculated as follows: