Combination of supercritical CO2 and ultrasound for flavonoids extraction from Cosmos sulphureus: Optimization, kinetics, characterization and antioxidant capacity

Abstract

A hyphenated technique using ultrasound-assisted supercritical CO2 extraction (UASCE) was developed to obtain flavonoids from Cosmos sulphureus. The highest total flavonoids content (TFC) achieved at 25 MPa pressure, 55 °C temperature, 10% cosolvent concentration, and 0.21 W/mL ultrasound energy density. UASCE improved TFC and antioxidant capacity of the extract, reduced extraction duration and extraction pressure, saved electric energy consumption and usages of CO2 and organic solvent, when compared with conventional extraction techniques. Furthermore, a high correlation between TFC and antioxidant capacity of the extract was found. HPLC analysis indicated that ultrasound effectively improved the individual concentrations of these flavonoids in extracts. Moreover, the kinetics study implied that the employed Sovová models were in good agreement with the experimental kinetic profiles. In conclusion, UASCE is a sustainable and efficient production technology in food and dietary supplement industries. Furthermore, Cosmos sulphureus can be considered as an attractive feedstock for natural flavonoids production.