Investigation on the structure characteristics, stability evaluation, and oral tribology of natural oleanolic acid-based water-in-oil high internal phase and multiple Pickering emulsions as realistic fat analogues

Herein, it proved that oleanolic acid (OA) could self-assemble into particles in oil, further exhibiting great potential in creating Pickering water-in-oil (W/O) high internal phase emulsions (HIPEs) with desirable fat-like attributes. W/O HIPE with a water content of 85 wt% could be stabilized by 3 wt% OA, their fat-like performance could be optimized by modulating the filling density of water droplets and interfacial coverage. The stabilization included particle-coated, particle and droplet co-coated, and droplet-coated interfaces depending on the OA amount. HIPEs with excellent tolerance to high-temperature and freeze-thaw treatment could be achieved. Moreover, dual-interface Pickering-stabilization water-in-oil-in-water (W/O/W) emulsions with a fat-like texture were fabricated via a one-step homogenization stabilized with OA particles and microgels. Importantly, OA-based W/O and W/O/W emulsion gels possessed smooth oral sensation and similar tribology behaviors to milk fat. This work is expected to provide a “clean-label” route to develop multiphase fat analogues involved in natural materials.