Separation and concentration of ω-3 PUFA-rich phospholipids by hydration of krill oil

Abstract

Krill oil (KO) is unique in contrast to fish oil because the ω-3 PUFAs, particularly eicosapentaenoic (EPA) and docosahexaenoic (DHA), are almost exclusively esterified on phospholipids (PL) rather than triglycerides (TAG) which improves bioavailability and water solubility. Therefore, the primary aim of this study was to use the principles of water degumming to separate PL from TAG in KO. Water was mixed with KO in varying ratios, centrifuged for separation and freeze-dried. Separation into gum and oil fractions occurred in the 75:25 and 50:50 KO:H2O samples. TLC-densitometry revealed 67.6 ± 1.97% and 49.73 ± 3.90% PL concentrations (p < 0.05) in the lipid recovered from the 75:25 and 50:50 KO:H2O sample, respectively. The 75:25 KO:H2O gum fraction did not contain detectable triglycerides (TAG); however, the 50:50 KO:H2O gum fraction had 23.88 ± 6.36% (p < 0.05). The fatty acid profile of the 75:25 KO:H2O gum fractions presented with more EPA and DHA than the oil fraction (p < 0.05). Phosphatidylcholine (PC) with EPA and DHA fatty acids attached concurrently at sn-1 and sn-2 (i.e., PC-EPA/EPA, PC-EPA/DHA, and PC-DHA/DHA) and was present in the gum fractions of both samples. This approach offers a simple separation technique to separate health-beneficial PL from KO.