Preparation of high internal phase Pickering emulsion gels stabilized by glycyrrhizic acid-zein composite nanoparticles: Gelation mechanism and 3D printing performance

High internal phase Pickering emulsion (HIPPEs) for three-dimensional (3D) printing have attracted increasing attention for application to foods. In this study, glycyrrhizic acid-zein composite nanoparticles (ZGNPs) were prepared via hydrogen bonding and electrostatic interactions. The properties of the ZGNPs were characterized by particle size, ζ-potential, and electron microscopy analysis. Using ZGNPs as emulsifiers, HIPPEs with an oil phase volume fraction of 75% were successfully fabricated. These HIPPEs showed good storage stability, shear-thinning behavior, and high viscoelasticity. Furthermore, their rheology and stability characteristics meant they could be used to as edible bio-inks for 3D printing applications. These HIPPEs was able to 3D-print selected shapes with high resolution and shape fidelity. Our results open new possibilities for producing Pickering emulsion gels with improved performance, which could be used as 3D printing inks for future food manufacturing and nutrition delivery systems.