Process integration for purification and concentration of red cabbage (Brassica oleracea L.) anthocyanins

Multistage aqueous two phase extraction was carried out using polyethylene glycol (PEG) 4000/magnesium sulfate (14.8/10.3%, w/w) system. The phase forming polymer (PEG 4000) was successfully separated from anthocyanins employing organic-aqueous extraction. Different processes employed for the purification and concentration of anthocyanins were compared with one another. The highest concentration of anthocyanins (3123.45 mg/L and 43 °Brix) was obtained in case of integration of aqueous two phase extraction with forward osmosis. Non-enzymatic browning index (0.11) and degradation constant (0.21) were found to be lowest in case of the integrated process involving aqueous two phase extraction followed by forward osmosis when compared to other processes. Color density was found to increase from 0.6 to 14.56 and stability of anthocyanins (with respect to pH and temperature) was found to be more in case of integrated process (aqueous two phase extraction followed by forward osmosis).