Fractional preparation of Antarctic krill oil and its quality analysis

Antarctic krill oil (AKO) refers to the lipid extracted from Euphausia superba. Recently, it has attracted great concerns from academia and industry due to its unique composition. However, the lack of standards, complex composition and differences in processing methods can easily lead to unstable quality of AKO products, which would further limit the in-depth research on its functional properties and restrict the development of the AKO industry. Thus, the fractional preparation of AKO and its quality analysis were conducted in this study. Firstly, the whole E. superba meal was used as the raw material, and soybean oil or medium chain triglycerides was used as the co-solvent carrier in conjunction with supercritical CO₂ extraction technology to prepare triglyceride-enriched oil (first grade oil). And then, the extracted E. superba meal was subjected to alcohol extraction to prepare a phospholipid-enriched oil (second grade oil). Considering the lipid composition, and content of phosphatidylcholine and phosphatidylethanolamine as the inspection indicators, 30% soybean oil was selected as the co-solvent carrier in conjunction with supercritical CO₂ extraction technology to prepare AKO. The results showed that, compared with the non-cosolvent group and the ethanol cosolvent group, the co-solvent carrier (30% soybean oil) group had the highest extraction rate of primary oil, suggesting the phospholipids of the first and second grade oils were effectively separated, and its polyene index, atherosclerosis index and thrombosis index were relatively low. The phospholipid content of AKO prepared by fractionation in the present study was significantly different, which not only enriched the types of AKO products, but also provided theoretical guidance for the selection and formulation of subsequent AKO extraction technology. It is suggested that the research of AKO in the future should focus on the influence of typical processes on the composition, structure and functional properties of AKO and their related mechanisms, which would be helpful to achieve precise regulation and efficient production of AKO with target functionalities.