The lipid type affects the in vitro digestibility and β-carotene bioaccessibility of liquid or solid lipid nanoparticles

Solid lipid nanoparticles (SLNs) are emulsion-based carriers of lipophilic bioactive compounds. However, their digestibility may be affected by the solid lipid phase composition. Hence, the aim of this work was to study the in vitro lipolysis kinetics as well as the relationship between the lipid digestion, micelle fraction composition and β-carotene bioaccessibility of SLNs with different solid lipids, being blends of medium chain triglyceride (MCT) oil, glyceryl stearate (GS) or hydrogenated palm oil (HPO) as compared to liquid lipid nanoparticles (LLNs) with pure MCT. SLNs formulated with GS were fully digested, similarly to LLNs. However, HPO-containing SLNs presented slower lipolysis kinetics during the intestinal phase at increasing HPO concentration. Despite this, HPO-SLNs showed higher β-carotene bioaccessibility, which was related to the higher amount of monounstaturated free fatty acids in the micelle fraction. Thus, this work provides valuable insight for designing delivery systems of bioactive compounds with optimal functionality.