Salmon and krill phospholipids: Two nanocarriers with interesting physico-chemical properties

This study compares salmon heads and krill as natural marine sources of omega-3-rich phospholipids for liposome formulation, serving as potential carriers of bioactive compounds in nutrition and preventive health. Salmon and krill oil obtained by green processes, yielded lipid fractions enriched in both neutral and polar lipids, containing esterified long-chain polyunsaturated fatty acids (LC-PUFAs) such as EPA and DHA. The triacylglycerol/polar lipid ratios were 0.71 for salmon and 0.39 for krill, with significant differences in lipid class distribution and phospholipid concentrations, determined via acetone fractionation. Polar fractions exhibited high LC-PUFA content: 5.36 % EPA and 13.90 % DHA respectively for salmon, whereas polar lipids in krill contained 12.96 % EPA and 7.26 % DHA. Nutritional and health-related indices including atherogenicity, thrombogenicity, polyene, health-promoting, oxidisability, peroxidisability, and hypo/hypercholesterolemic ratios, highlighted the specific advantages and limitations of each source. The relative proportions of fatty acids influenced the physicochemical properties of the resulting liposomes. Dynamic Light Scattering and Nanoparticle Tracking Analysis revealed particle sizes of ∼86.56 nm for salmon and 176.22 nm for krill liposomes, with highly negative zeta potentials ensuring long-term colloidal stability. Both liposome types showed good size homogeneity, low polydispersity indices (∼0.2), and favorable particle mobility under imaging. Overall, these marine by-products represent sustainable sources of polar lipids naturally enriched in EPA, DHA and astaxanthin, the main carotenoid present with well-documented antioxidant properties, providing functional and nutritional benefits. This highlights their significant potential for the development of lipid-based delivery systems in food, nutraceutical and health applications.