Fortification of Sunflower Oil by Nanoemulsions Containing Vitamin-D₃: Formation, Stability, and Release

This study addresses the challenge of stabilizing vitamin D₃, an unstable, fat-soluble vitamin, whose efficacy is diminished by environmental factors. The objective was to encapsulate vitamin D₃ using pectin (1%-3% w/w) and whey protein concentrate (WPC) (1%-2% w/w) at varying ratios, facilitated by Tween 80 surfactant (0.5% and 2.5% w/w), through high-pressure homogenization to create oil-in-water (O/W) nanoemulsions. Optimization of the preparation conditions for both aqueous and oil phases was conducted using an experimental design. Characterization and stability of the nanoemulsions were assessed using scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). Release kinetics of vitamin-D₃ into sunflower oil were monitored using high-performance liquid chromatography (HPLC) under various conditions. The optimal encapsulation was achieved with a 30:70 oil-to-aqueous phase ratio, comprising 27.5% oil and 2.5% surfactant in the oil phase, and 1% WPC and 2% pectin in the aqueous phase. The nanoemulsion demonstrated stability over 60 days of storage, with a z-average particle size of 98.2 nm. HPLC analysis indicated a 90% recovery of encapsulated vitamin-D₃ in sunflower oil. These findings suggest the promising approach of the developed nanoemulsion for enhancing the bioavailability and shelf life of vitamin-D₃ in food applications.