Enhancing the physicochemical stability of β-carotene solid lipid nanoparticle (SLNP) using whey protein isolate

β-Carotene is a nutraceutical that acts as a coloring agent and as pro-vitamin A, but its incorporation into foods is limited because of its hydrophobicity and low chemical stability. The aim of this study was to improve the physicochemical stability of β-carotene by encapsulating into solid lipid nanoparticles (SLNPs) containing palmitic acid and corn oil, stabilized using whey protein isolate (WPI). The palmitic acid crystals covered the surface of the oil droplets and formed a solid shell to protect the encapsulated β-carotene. Corn oil decreased the exclusion of β-carotene from the solid lipid matrix to the surface of SLNPs. WPI increased the colloidal stability of the system, and improved β-carotene oxidative stability. The rate of color fading due to β-carotene degradation increased with increasing temperature and was faster at lower pH. Lower ionic strengths had a slight impact on β-carotene degradation, while higher ionic strengths accelerated β-carotene breakdown.