Determination of total anthocyanins content (TAC)

TAC was measured spectrophotometrically by the pH differential method (Machado et al. 2015) which based on the transformation of anthocyanin chromophore structural under different pH (coloured at pH 1.0 and colourless at pH 4.5). The absorbance was measured using a spectrophotometer (UV-2450, Shimadzu, Kyoto, Japan). The calculation of TAC was based on cyanidin-3-glucoside equivalents. Results were expressed as mg cyanidin-3-O-glucoside equivalent per 100 g dry weight (mg CGE/100 g dw).