Influence of type of natural emulsifier and microfluidization conditions on Capsicum oleoresin nanoemulsions properties and stability

Abstract There is a growing interest in the fabrication of colloidal delivery systems for bioactive compounds assembled from natural ingredients, particularly plant‐based ones. In this study, Capsicum oleoresin was encapsulated within oil‐in‐water nanoemulsions by high‐pressure microfluidization from natural emulsifiers: whey protein (WP), pea protein (PP), quillaja saponin (QS), and sunflower lecithin (SL). The influence of emulsifier, concentration, and microfluidization conditions (pressure and number of passes), on particle diameter and zeta‐potential of nanoemulsions was evaluated. Particle diameter decreased with increasing homogenization pressure and number of passes. All emulsifiers were capable of forming charged droplets with dimensions in the nanometer range at sufficiently high concentrations. The stability of nanoemulsions to environmental stresses (pH, ionic strength, and heating) and storage was studied. The pH and salt stabilities were dependent on the emulsifier type. Overall, natural emulsifiers were effective in producing Capsicum oleoresin‐loaded nanoemulsions with small particle size and capsaicin stability.