Green extraction of mulberry anthocyanin with improved stability using β-cyclodextrin

BACKGROUND Mulberry anthocyanin is reported to possess various biological activities and it is unstable during extraction or food production. The use of organic solvents for extraction of mulberry anthocyanins may cause environmental pollution and safety concerns. Therefore, the aim of this study was to investigate the effect of a green extraction solvent (cyclodextrin) on the recovery of anthocyanin from mulberry fruits, as well as the thermal stability of anthocyanin. RESULTS beta-Cyclodextrin (beta-CD) or hydroxypropyl-beta-cyclodextrin showed better anthocyanin extraction efficiency than water and ethanol aqueous solution for all tested mulberry cultivars. A molecular docking study indicated that anthocyanin (cyanidin-3-O-glucoside) was encapsulated in the cavity of beta-CD, thus enhancing the solubility of anthocyanin. The extraction process was subsequently optimized using a Box-Behnken design. The optimal extraction conditions for anthocyanin and antioxidant activity were found at extraction temperature of 20 degrees C, extraction time of 44.95 min and beta-CD concentration of 45 g L-1. Furthermore, a degradation kinetic study demonstrated that addition of beta-CD could significantly improve the thermal stability of anthocyanin during extraction, with the activation energy of anthocyanin degradation increasing from 63.06 to 76.77 kJ mol(-1). CONCLUSIONS Overall, our study suggests that beta-CD is an alternative green extraction solvent for the recovery of anthocyanins, and addition of beta-CD may potentially increase the thermal stability of anthocyanin during the extraction, which may give guidance for functional beverage production. (c) 2018 Society of Chemical Industry