Characterization of phospholipids extracted from Atlantic salmon by-product using supercritical CO2 with ethanol as co-solvent

Abstract

Abstract Marine (PLs) are rich in omega-3 polyunsaturated fatty acids (ω-3 PUFAs), and the good emulsifying property of PLs makes them suitable for use in the food, pharmaceutical, and cosmetic industries. This research was attempted to evaluate Atlantic salmon frame bone (SFB) PLs extracted by using supercritical carbon dioxide (SC-CO2) with ethanol as co-solvent extraction and organic solvent (ethanol) extraction. SC-CO2 with ethanol as co-solvent extraction was performed at 45 °C and different pressures (22.5–30.0 MPa) while maintaining a CO2 flow rate of 27 g/min and a co-solvent ethanol flow rate of 3 mL/min for 2.5 h. Extracted PLs were analyzed for a wide range of physico-chemical properties such as yield, PL purity, astaxanthin content, major PL groups, fatty acid composition, acid value (AV), peroxide value (POV), free fatty acid (FFA) value, and p-anisidine value (PAV). Thin layer chromatography was performed for qualitative analysis of different PL groups, and quantitative analysis was performed by high performance liquid chromatography with evaporative light scattering detection. The maximum PL yield of the SC-CO2 with ethanol as co-solvent extraction was 6.9 ± 0.3% of de-oiled SFB at 45 °C and 27.5 MPa, with 80.4 ± 1.6% purity. Among the four major groups of PLs identified, phosphatidylcholine was most common PL extracted, and the content varied from 79.6 ± 0.4% to 86.5 ± 0.3% for different extraction conditions. The stability parameters such as AV, POV, FFA value, and PAV of the SC-CO2 with ethanol as co-solvent extracted PLs were lower than those for organic solvent (ethanol) extracted PLs. SFB PLs showed significant thermal stability and contained substantial amounts of ω-3 PUFAs. PLs obtained by SC-CO2 with ethanol as co-solvent extraction showed better emulsion and free-radical scavenging properties than those of organic solvent (ethanol) extracted PLs. This research may be helpful in the SC-CO2 extraction of phospholipids from marine sources for researchers and food/pharmaceutical industries.