The response surface methodology (RSM) was used to evaluate the influence of two independent variables namely extraction temperature and extraction pressure via literature data obtained from supercritical fluid extraction (SFE) process of Sclerocarya birrea kernel oil. The optimal (custom) option was utilised on Design Expert Version 13 to optimise the variables taken into consideration. The raw experimental data comprised of 9 experimental runs of which the temperature was varied between 40, 60 and 75 °C and the pressure was varied between 250, 350 and 450 bar. The reaction time, particle size and carbon dioxide (CO2) flowrate was kept constant at 30 kg CO2/hour for all experimental runs.
