Encapsulation of fish oil in natural wax-based solid lipid particles using supercritical carbon dioxide: a green strategy to develop stable powder fish oil

Fish oil has received significant attention owing to its high omega-3 fatty acid content. Regular fish oil consumption can supply enough omega-3 fatty acids to human metabolism. However, omega-3 fatty acids consist of a high amount of polyunsaturated fatty acids that are prone to oxidation, and hence, the storage, transportation, and processing of fish oil are challenging. Therefore, fish oil needs to be transformed into an easy-to-use and stable formulation. The objective of this study was to load fish oil into hollow solid lipid particles using a particle formation technique based on supercritical carbon dioxide (SC-CO₂). Powder formulations of fish oil were obtained using two different natural waxes, namely, candelilla and carnauba wax, at different initial fish oil concentrations (30, 40, and 50% w/w). All particles exhibited a spherical shape with a smooth surface. The melting point of the particles decreased on increasing the initial fish oil concentration. The highest loading efficiency was achieved at 50% w/w, with the initial fish oil concentration for candelilla and carnauba wax particles at 72.9% and 92.5%, respectively. Moreover, accelerated oxidative stability tests for 21 days of storage proved that the SC-CO₂-assisted particle formation technique successfully protected fish oil against oxidation and increased the shelf life of fish oil. Loading fish oil into waxes enhanced the bioaccessibility of EPA/DHA fatty acids regardless of the wax type, from 6.1% to 8.5% and 11.2% in CLW and CW particles, respectively. Thus, the findings suggest that SC-CO₂-assisted particle formation could be an efficient method for forming more stable fish oil formulations.