Ultrasound-Assisted Extraction of Phenolic Compounds from Moroccan Lavandula stoechas L.: Optimization Using Response Surface Methodology

Figure 5

(a) Isoresponse plot showing the optimal compromise zone leading to the desired TPC (190 mg EAG/g) obtained by fixing the third parameter (ethanol (%)) in its low level (40%) and varying the other two parameters. (b) 3D plot of the response TPC in terms of extraction time and liquid/solid ratio effects and by fixing the concentration of ethanol at 40%.

(a)

(b)