The total anthocyanin concentration was determined using
the pH-differential method (Lee et al., 2005; Hosseinian et al.,
2008; Jampani et al., 2014). The anthocyanin-rich samples
were diluted with 0.025mol/L potassium chloride buffer (pH
1.0) and 0.4mol/L sodium acetate buffer (pH 4.5), and equilibrated
for 20min. To determine the appropriate dilution factor, the samples were first diluted with pH 1.0 buffer until
the absorbance at wavelengths between 520 and 530nm was
within the linear range ofthe spectrophotometer (Agilent 8453
UV-Vis Spectrophotometer).