Influence of operating parameters on supercritical fluid extraction of essential oil from turmeric root

Abstract Turmeric oil was extracted from Curcuma Longa herb (turmeric root) using supercritical fluid extraction (SFE) process. Full-face central composite design was employed to optimize operating parameters of the process. These parameters were pressure, temperature, solvent flow rate, particle size and addition of co-solvent (ethanol) that varied as 20–40 MPa, 40–60 °C, 5–15 g/min, 0–0.8 mm and 0–15% of solvent rate, respectively. Turmeric oil yield found through Soxhlet extraction was 5.954 wt% of turmeric powder whereas through SFE, it varied from 2 to 5.3 wt%. Turmerone and curcumin were identified as principle compounds of turmeric essential oil, which were analyzed using Gas chromatography–mass spectrometry and Ultraviolet–visible Spectrophotometer, respectively. Experimental data of oil yield, Curcumin content and Turmerone content were fitted well in the Quadratic model. Optimized values of operating parameters for maximizing these responses were also predicted. Further, economic assessment of SFE of turmeric oil at industrial scale for 60 t/y production capacity was performed.