Absorbance was measured at
535 nm against a reagent blank. Cyanidin 3-glucoside or Kuromanin
from Extrasynthese (Genay, France) was used as a standard pigment.
A series of cyanidin 3-glucoside standard solutions was prepared at
0–0.02 mmol (0–27 mg/3 mL). Absorbance was read at 535 nm
against a reagent blank. The concentrations showed a linear relationship
against absorbance (Fig. 1) and had regression and determination
coefficients of 0.0197 and 0.999, respectively. Total anthocyanin
content per sample (mg/kg) was calculated as cyanidin 3-glucoside: