A parametric study of supercritical carbon dioxide extraction of oil from Moringa oleifera seeds using a response surface methodology

This paper reports a study of supercritical CO2 extraction of oil from Moringa oleifera seeds using a SFT Custom SCW-SFE system. The effects of pressure, temperature, flow rate of supercritical fluid and extraction time on the oil yield were investigated using a central composite experimental design strategy to determine the significant parameters and their interactions. The experimental results showed that increasing pressure, extraction time, and the CO2 flow rate significantly increased the oil yield. However, the effect of temperature on the oil yield was also found to depend on the pressure with the oil yield increasing with increasing temperature at high pressures but decreasing at low pressures. In addition, the effect of particle size on the oil yield was also investigated and it was found that the oil yield increased with the decreasing particle size, suggesting that the intraparticle diffusion played an important role. The oil extracted was characterized using a GC and NMR and compared against oil extracted using the Soxhlet extraction. Oleic acid, a high-value monounsaturated Omega-9 fatty acid, was the main components in the oils, it accounted for nearly 70% of all the fatty acids present in the oil extracted. Although the oil yield of the supercritical fluid extraction was slightly lower than that of the Soxhlet extraction, the GC and 1H NMR analysis indicated that the chemical compositions of the oils extracted by these two methods were very similar. © 2013 Elsevier Ltd. All rights reserved.