Effects of interfacial composition on the stability of emulsion and encapsulated bioactives after thermal and high pressure processing

The composition of the oil-in-water (O/W) interface of emulsion droplets plays a critical role in their physicochemical stability as well as that of encapsulated bioactives during processing. This study evaluates three emulsifiers, whey protein isolate (WPI), Tween 20 and Ludox HS-30 silica (Pickering), which stabilize O/W emulsions containing either all-trans retinol or curcumin, and determines the physicochemical stability of the emulsion and encapsulated bioactives post processing. In addition to thermal methods, this study utilizes high hydrostatic pressure processing (HPP) (600 MPa for 5 min). Physical stability of emulsions was characterized using particle size and ζ-potential measurements. Recovery of bioactives was determined using UV-vis spectrophotometry. WPI emulsions maintained a constant particle size across all processing parameters compared to other formulations. Tween 20 provided the most protective effect to encapsulated bioactives during processing. HPP had no significant effect on the physicochemical stability for any emulsion and had minimum effect on bioactive recovery.