The effect of ultrasound process on the extraction yield and the quality of edible oils

This research investigated the impact of ultrasonic-assisted extraction (UAE) on the properties of various edible oils: unstable (flaxseed, fish), semi-stable (soybean), and thermally stable (sesame). Oil was extracted using n-hexane and petroleum ether with UAE for 15, 30, and 60 min at 25 °C, 160 W power, and 50 kHz frequency. The highest yields of flaxseed, sesame, soybean, and fish oil extracted using hexane and petroleum ether solvents were observed after 60 min. In hexane, the extraction increases from 15 to 60 min, where 6.73 % (flaxseed), 15.25 % (fish), 4.88 % (soybean), and 19.74 % (sesame). In petroleum ether, the increases were 5.16 % (flaxseed), 11.80 % (fish), 3.96 % (soybean), and 0.86 % (sesame). For 60 min, UAE increased peroxide values (PV) and conjugated dienes value (CDV) in flaxseed and fish oils more than in soybean and sesame oils, although it didn't affect the refractive index. The method generated higher levels of primary oxidation compounds in flaxseed and fish oils, while polyunsaturated fatty acids significantly decreased in these oils. Additionally, n-hexane solvent yielded more oil than petroleum ether in the UAE process. Thus, UAE extraction of unstable oils is not advisable due to the rise in PV and decrease in unsaturated fatty acids.