High internal phase Pickering emulsions co-stabilized by zein nanoparticles and cellulose nanocrystals: Fabrication, characterization, and application

Abstract

There has been great interest in the development of edible high internal phase Pickering emulsions (HIPPEs) for a variety of applications in the food industry, including enhancing shelf life and creating novel textures. However, it is often challenging to create HIPPEs with the required stability, texture, and processability. Herein, we prepared HIPPEs using Pickering emulsifiers (2%) consisting of different mass ratios of zein nanoparticles and cellulose nanocrystals (CNC). The hydrophobic interaction and hydrogen bond between zein nanoparticles and CNC were the main ways to stabilize HIPPEs. Meanwhile, the compact three-dimensional network structure formed by these nanoparticles and nanocrystals increased the stability and rheological properties of the HIPPEs. As the mass ratio of zein nanoparticles to CNC increases from 1:2 to 2:1, the storage modulus increases from about 545 Pa to 2790 Pa, which indicated that the texture of HIPPEs can be modulated by adjusting the mass ratio of zein nanoparticles to CNC. Moreover, rheological properties analysis displayed that the HIPPEs were viscoelastic materials with predominantly solid-like characteristics and good texture recoverability after shearing. Cryogenic scanning electron microscopy results observed that zein nanoparticles and CNC formed a coating around the oil droplets, and they formed filamentous network connections between different oil droplets. Finally, the incorporation of HIPPEs into cookies proved to be an effective fat replacer, and the HIPPEs replaced butter could improve their overall appearance and color. HIPPEs may therefore be used as butter substitutes in some food products, but further research is required to optimize their application.