Storage Stability and Antioxidant Properties of Vegetable and Marine Lecithin Liposomes Loaded with Sea Cucumber (Holothuria forskali) and Musky Octopus (Eledone moschata) Protein Hydrolysates

This study is aimed at comparing how the lipid composition of lecithins from vegetable and marine sources affects the properties and storage stability of liposomes and at evaluating their capacity to encapsulate two protein hydrolysates derived from undervalued marine invertebrates. The particle properties (size, polydispersity index or PDI, and zeta potential), thermal properties, in vitro antioxidant properties, and angiotensin-converting enzyme (ACE) inhibitory capacity of liposomes produced from soybean, sunflower, and herring roe lecithin were compared. All lecithins exhibited a high polyunsaturated fatty acid (PUFA) content (52.7 - 59.18%); however, for the marine-derived lecithin, rich in long chain omega-3 fatty acids, a partial purification process of phospholipids was required to obtain a stable liposomal dispersion. Mean particle sizes of 212 nm, 130 nm, and 96 nm were obtained for sunflower lecithin (LSun), soy lecithin (LSoy), and partially purified marine lecithin (LMarP) liposomes, respectively, all with electronegative zeta potential. Two protein hydrolysates obtained from sea cucumber and musky octopus protein concentrates were successfully encapsulated in liposomes prepared with the respective lecithins and then characterised. The hydrolysates provided liposomes with high ACE-inhibitory capacity; however, antioxidant properties were highly dependent on the lecithin source. Unloaded and loaded liposomes presented high colloidal stability during 4 weeks of chilled storage. Finally, a principal component analysis (PCA) was conducted to summarise and interpret the results. Liposomes derived from marine phospholipids offer a nutritious alternative, due to their long-chain omega-3 fatty acid content, high biological activity, and favourable structural attributes.