Incorporation of curcumin-loaded lipid nanoparticles into a cloudy apple juice: study of the chemical and colloidal stability, in vitro digestibility and bioaccessibility.

This study examined the influence of the food matrix composition on the chemical and colloidal stability as well as functionality of curcumin-loaded lipid nanoparticles with different lipid phase state (liquid vs. solid). For this, lipid nanoparticles formulated with medium-chain triglycerides (MCT), MCT with glyceryl stearate (MCT + GS), or coconut oil (CNUT) were dispersed into aqueous phases with varying degrees of complexity, being aqueous solutions of the main components of cloudy apple juice. The physicochemical characteristics and colloidal stability of curcumin-loaded lipid nanoparticles was not dramatically affected by its incorporation into the food matrix. Remarkably, curcumin retention (%) of lipid nanoparticles was higher when they were incorporated into the food matrix. In general, lipid nanoparticles after incorporation into a cloudy apple juice exhibited a slower lipid hydrolysis during in vitro digestion conditions compared to the lipid nanoparticles alone, yet reaching to higher free fatty release at the end of the intestinal phase. Moreover, lipid nanoparticles in cloudy apple juice demonstrated significantly higher curcumin bioaccessibility compared to the lipid nanoparticles alone. Among the lipid-phase formulations, solid lipid nanoparticles (SLNs) exhibited greater curcumin bioaccessibility than liquid lipid nanoemulsions (LLNs), with CNUT-SLN achieving the highest bioaccessibility (39.10 ± 0.61%) in cloudy apple juice. These results highlight the critical roles of lipid phase state and food matrix composition in determining the digestive fate and bioaccessibility of encapsulated lipophilic compounds. The study supports the potential of lipid nanoparticles and fruit-based beverages as promising platforms for delivering curcumin and other hydrophobic bioactives in functional food applications.