Separation and concentration of phospholipids and glycerides from ethanol extraction of krill by hydration and solvent partitioning

The main components of Antarctic krill oil are glycerides and phospholipids, and the sn-1 and sn-2 positions of the phospholipids are occupied by eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which improves their bioavailability and water solubility. This study aimed to efficiently separate and concentrate glycerides and phospholipids rich in ω-3 unsaturated fatty acids from Antarctic krill with the help of ethanol, water, and n-hexane, utilizing the hydrophilic-lipophilic balance (HLB) differences between products and the phase equilibria between solvents. The extraction ratio, species and contents of phospholipids, glycerides, cholesterol, astaxanthin, fatty acid composition, and smell characteristics changes of the two products were characterized, and the influence of temperature on the experiment was discussed. The optimal solvent ratio wasxH2O:xC2H5OH:xC6H14 = 2: 5: 3 and the ideal hydration temperature was 40 °C. Under these conditions, two products were obtained, N-H and E-W, the extraction yield of N-H was 19.6 %, and glycerides was its main component (89.8 %) with rich astaxanthin (292.3 mg/kg); the extraction yield of E-W was 13.2 %, mainly composed of phospholipids (92.4 %), which was also rich in EPA and DHA (37.9 % and 11.9 %, respectively). This study provides a theoretical basis and technical guidance for the development of new products of Antarctic krill.