Comparative studies on the yield and quality of solvent-extracted oil from salmon skin

Oil was extracted from the skin of Atlantic salmon by solvent extraction with different solvent systems and analyzed for efficiency in terms of oil yield and quality. The yield of salmon skin oil (SSO) was significantly lower (p < 0.05) with the hexane-isopropanol solvent system versus either of the chloroform-methanol systems, i.e., 32.21% on dry weight basis (dwb) against 35.15% dwb and 43.82% dwb, respectively. Second and third extractions were performed on the residue using the same solvent systems to verify any biases and to test the completeness of the first extraction. These successive extractions resulted in nominal increases in yield. The yield of SSO from Soxhlet-hexane compared favorably with Soxhlet-petroleum ether at all the extraction times investigated. The Soxtec-hexane gave the highest oil yield of ca 62% dwb. Both hexane and petroleum ether were suitable solvents for the extraction of SSO, though the yield obtained with hexane was significant higher (p < 0.05). The study further indicated that salmon skin was a rich source of oil (23.32-61.53% dwb) and for the various solvent systems, the free fatty acid (FFA) content was quite low (0.60-1.19%). (C) 2008 Elsevier Ltd. All rights reserved.