Fig. 4.
Contour diagram of the influence of the change of the pH value (x1) ranged from 3 to 6, temperature of extraction (x2) ranged from 30 to 60 °C for time set to 30 min on the antioxidant activity (y1), total phenolic content (y2), and on the individual content (mg/mL) of delphinidin-3-gl (y1), cyanidin-3-gl (y2), petunidin-3-gl (y3), peonidin-3-gl (y4), malvidin-3-gl (y5), catechin (y1), gallic acid (y2), rutin (y3), quercetin (y4) and kaempferol (y5), during the optimization of extraction conditions using 23 CCF full factorial DoE