Essential Oil Extracted from Cymbopogon citronella Leaves by Supercritical Carbon Dioxide: Antioxidant and Antimicrobial Activities

Figure 2

Response surface plot (3D and 2D) for the interactive effect of variables. (a) Effect of CO₂ flow and extraction temperature with fixed extraction time and extraction pressure at 120 min and 25 Mpa, respectively; (b) effect of extraction time and extraction pressure with fixed CO₂ flow and extraction temperature at 18 L/h and 35°C, respectively; (c) effect of CO₂ flow and extraction pressure with fixed extraction time and extraction temperature at 120 min and 35°C, respectively; (d) effect of extraction time and extraction temperature with fixed CO₂ flow and extraction pressure at 18 L/h and 25 MPa, respectively; (e) effect of CO₂ flow and extraction time with fixed extraction temperature and extraction pressure at 35°C and 25 MPa, respectively; (f) effect of extraction temperature and extraction pressure with fixed CO₂ flow and extraction time at 18 L/h and 120 min, respectively.

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