Comparison of Four Different Extraction Methods of Oil from <i>Macadamia integrifolia</i>

Abstract

Four different extraction methods, solvent extraction, ultrasonic wave-assisted extraction, Soxhlet extraction and supercritical CO2 extraction, were used to extract oil from Macadamia integrifolia, which also named Macadamia nut oil. Fatty acid compositions of Macadamia nut oil were analyzed by gas chromatography and mass spectrometry (GC-MS). The results showed the highest extraction rate was 74.63% via Soxhlet extraction, while supercritical CO2 extraction was 70.53%, ultrasonic wave-assisted extraction was 57.19% and Solvent extraction was 50.37%. Six unsaturated fatty acids, including Z-9-Hexadecenoic acid, E-11-Hexadecenoic acid, 9,12-Octadecadienoic acid, 9-Octadecenoic acid, E-9-Octadecenoic acid and 9-eicosenoate, were identified in the oil by GC-MS．The relative extraction rate of unsaturated fatty acids were 36.53%, 44.21%, 60.62%, 56.81%, respectively. Though the extraction rate was the highest via Soxhlet extraction, the relative content of Z-9-Hexadecenoic acid and 9,12-Octadecadienoic acid were both higher extracted by supercritical CO2 extraction than Soxhlet extraction, which were 15.38% and 1.55%,. As supercritical CO2 extraction has no solvent residual problem, it would be the trend of the development inSubscript text the future to extract Macadamia nut oil.