Improvement of the physical stability of oil-in-water nanoemulsions elaborated with Sacha inchi oil employing ultra-high-pressure homogenization

Abstract This study focused on assessing the physical stabilization of several oil-in-water nanoemulsions obtained by Ultra-High-Pressure Homogenization (UHPH). For this, several formulations were developed using Sacha inchi oil (~9.3% w/w), ultra-pure water, preservatives (0.44% w/w) and several emulsifier mixtures at 2% w/w, which were combined in different proportions to provide surfactant blends with HLB values (HLBB) of 6, 8, 10, and 12. The conventional emulsions were then subjected to UHPH (40,000 psi) and underwent thermal stability assays for 4 weeks, where changes in creaming index, droplet size, polydispersity, viscosity and zeta potential, were evaluated. The results showed the required HLB (HLBr) for SI oil was approximately 8 and when UHPH was utilized, high physical stability of emulsified systems was achieved. It was also found that the increase in HLBB for the emulsions submitted to UHPH leads to a less viscosity, smaller droplet sizes and more homogeneous system.