A review on column CO2 fractionation methods from fish oil to omega-3, 6 and 9

Abstract

Commercial interest in getting polyunsaturated fatty acid concentrates, especially omega-3 fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) was increasing. Unsaturated fatty acids could prevent cardiovascular disease and improved cognitive function of the brain. Fish oil was the main source of fatty acids, especially omega-3 fatty acids. The content of omega-3 fatty acids (24%), omega-6 (5.37%) and omega-9 (12.6%) fish oil were quite high. Fish oil concentrate was needed in the food and pharmaceutical industries. Degradation of thermolabile compounds cannot be avoided in conventional separation methods. Some conventional oil separation methods had weaknesses and strengths. Column chromatography: the concentrate was very difficult to separate so it required a lot of solvents; distillation: low oil yield due to a lot of yawning; centrifugation: the results were heterogeneous; membrane: easy to plug; using solvents: low cost, technology exists, could be at room temperature and atmospheric pressure, the results were homogeneous. The choice of solvent determined the level of yield and safety. CO2 as a solvent was non-polar, non-toxic, volatile, high diffusivity, low surface tension, low viscosity, good extract degradation, low critical temperature, (31 °C), could prevent thermal degradation, fast, cheap and efficient.