Supercritical CO2 extraction of chlorogenic acid from sunflower (Helianthus annuus) seed kernels: modeling and optimization by response surface methodology

In this research, supercritical CO2 extraction of chlorogenic acid (CGA) from sunflower seed kernels was investigated by ethanol as co-solvent. The effects of operating conditions including temperature (40-80 degrees C), pressure (10-30 MPa), CO2 flow rate (0.6-1.8 ml/min) and dynamic extraction time (40-120 min) was investigated on the chlorogenic acid (CGA) extraction recovery. The flow rate of ethanol and static extraction time were kept constant at 5 vol. % of CO2 flow rate and 25 min, respectively. The quantification of extracted samples was performed by high performance liquid chromatography (HPLC). Minitab 17 software was used to create the response surface design for the modeling and optimization of extraction recovery. Experimental data were fitted by a second order polynomial and the coefficient of determination was obtained to be 96.75%. Optimum recovery of CGA (52.08%) was obtained at 17.9 MPa, 40.0 degrees C, 104.6 min and 1.6 ml/min.