Response surface optimization of supercritical CO2 extraction of α-tocopherol from gel and skin of Aloe vera and almond leaves

Response surface (a) and contour (b) plots for α-tocopherol extraction recovery (R) from AVG as a function of coded values of pressure (P) and temperature (T) at SC-CO2 flow rate of 1 ml/min and dynamic time of 100 min.