Optimisation of process variables for antioxidant components from Crataegus monogyna by supercritical fluid extraction (CO2) using BoxBehnken experimental design

Abstract The aim of this study was to optimize the percentage yield and percentage radical scavenging activity (RSA) of hawthorn leaf/flower ( fol/flos  = FF) and hawthorn berries ( fructus  = Fr) using supercritical carbon dioxide as the extraction technology. Response surface methodology was employed, using a Bex⿿Behnken statistical design to evaluate the effects of three independent variables. Pressure (100⿿400 bar), temperature (40⿿60 °C) and modifier (ethanol) concentration [no modifier (0%), 45%, 90%] were the three variables with total extraction time and CO 2 flow rate being held constant at 35 min and 5 L/min, respectively, for each extraction. Antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Optimal extraction conditions, as predicted by response surface methodology were; pressure of 400 bar, temperature of 50 °C and use of no modifier for hawthorn leaf/flower and, pressure of 310 bar, temperature of 60 °C and use of no modifier for hawthorn berries.