Enhanced physical stability and release profile of DHA algal oil liposomes using different protein coatings

This study investigated the physicochemical properties, stability, and in vitro release of DHA algal liposomes coated with lactoferrin (LF), whey protein isolate (WPI), and soy protein isolate (SPI). The microstructure of liposomes were characterized by TEM, AFM, FTIR, and fluorescence spectroscopy, while their stability, and in vitro release behavior were systematically evaluated. The results showed that protein coating significantly improved the physicochemical stability of the liposomes. Among the three proteins, LF-coated liposomes (LF-Lip) exhibited the smallest mean particle size of 88.94 nm and the most uniform size distribution, with a PDI of 0.196. FTIR and fluorescence spectroscopy confirmed that the proteins interacted with liposomes primarily through hydrogen bonding and electrostatic interactions, with LF showing the strongest binding affinity. Antioxidant assays demonstrated that compared with unmodified liposomes, those coated with LF, exhibited 1.24 times greater scavenging activity against DPPH radicals. Liposomes coated with LF showed superior stability under acidic, ionic, and thermal stressors. After 28 days of storage at 4 °C, the encapsulation efficiency remained at approximately 88.96%. In vitro release experiments showed that protein coating significantly delayed the release of DHA alginate oil. The release rate of LF-Lip was significantly lower than that of the uncoated liposomes in the first 6 h, and the release curve conformed to the first-order kinetic model. After 6 h, the release rate gradually increased until 48 h, reaching a cumulative release rate of 82.48%. Overall, LF provided the most pronounced enhancement in the stability and sustained release of DHA algal oil liposomes, providing a theoretical basis and technical support for the efficient delivery and stabilization of DHA algal oil in food systems.