Quantitative and qualitative characterization of mango kernel seed oil extracted using supercritical CO₂ and solvent...

Characterization of mango kernel seed oil extracted using supercritical CO₂ (SC-CO₂) and conventional solvent (hexane, petroleum ether, ethanol and acetone) extraction techniques was carried out using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), Gas chromatography mass spectroscopy (GC-MS) and fluorescence microscope. The extractor and separator temperatures of the SC-CO₂ were 60 and 50 °C respectively while the pressure was varied from 35 to 40 MPa. Solvent extractions were maintained at the boiling points of the various solvents. The results indicated that solvent extraction had higher yields (8.02-19.88%) while SC-CO₂ had a lower yield (2.5-3.6 %); the yield of conventional solvent extraction increased with decreasing particle sizes. Ethanol extracted oil had lowest enthalpies of endothermic reaction (1.17-2.74 J/g); while other solvents were between 42.54 and 45.64 J/g with SC-CO₂ having 37.40 J/g. The melting points for ethanol extracted oil were 7.34 and 35.20 °C; other solvents ranged between 13.39 and 15.15 °C while, SC-CO₂ was 35.05 °C. SC-CO₂ extracted oil had no crystallization parameter, while conventional solvent extracted oil with the exception of ethanol were between -33.23 and -33.97 J/g. The FTIR showed that CH₃, CH₂ and COH were the predominant functional groups in hexane, petroleum ether, acetone and SC-CO₂-extracted oil; ethanol extracted oil had -OH and CH₂. The extracted oil using solvent extraction technique was higher in unsaturated fatty acid (UFA) with the exception of acetone extracted oil. SC-CO₂ extracted oil had higher saturated fatty acid (SFA) content (47.01%). The predominant UFA and SFA were oleic acid stearic acid.