Extraction and phase behaviour of Moringa oleifera seed oil using compressed propane

Abstract

AbstractThis study reports the oil extraction efficiency using Moringa oleifera seed and pressurized propane, new experimental data for phase transition of the binary system {n‐propane + Moringa oleifera oil}, and the profile of fatty acid compositions of the extracted Moringa oil. During the present study, the knowledge of the phase behaviour proved to be of great importance to optimize supercritical extraction using pressurized fluid. This project also compares the classical Soxhlet method including mathematical modelling of kinetic curves of extraction. The extraction experiments were performed in the temperature and pressure ranges of 303–333 K and 2.5–12 MPa, respectively, at a constant flow rate of 1.0 cm3/min of n‐propane. All the conditions applied during the n‐propane extraction process provided similar or higher yields (32.8 to 42.1 %) compared to extractions using n‐hexane (42.6 %) and supercritical carbon dioxide (SC‐CO2) (37.8 %). In addition, phase transition study for the {Propane (1) + Moringa oleífera oil (2)} system was performed using a variable volume cell and the static synthetic method in a temperature range of 303–343 K, pressures up to 3.23 MPa, and n‐propane mass fraction between 0.2 and 0.8. Vapour‐liquid (VLE), liquid‐liquid (LLE), and vapour‐liquid‐liquid (VLLE) phase transitions were observed at relatively low pressures. The fatty acid profiles of the extracted Moringa oils were evaluated using gas chromatography. They all have very close composition regardless of the solvent used and oleic acid as the major component (≈76 %). The Sovová mathematical model indicated a good fit for all the conditions investigated.