High internal phase Pickering emulsions (HIPPEs) prepared from natural polymers have attracted much attention in the food manufactures. However, single zein-stabilized HIPPEs are poorly stable and prone to flocculation near the isoelectric point. To address this issue, in this study, zein and whey protein nanofibrils (WPN) complex nanoparticles (ZWNPs) were successfully prepared using a pH-driven method, and ZWNPs were further used as HIPPEs stabilizers. The results showed that zein and WPN were combined together through hydrogen bonding and hydrophobic interaction to form ZWNPs, and the HIPPEs stabilized by ZWNPs had excellent stability, which could effectively protect the internally encapsulated lycopene and improve the bioaccessibility of lycopene. In conclusion, this study provides a new strategy for the preparation of stable hydrophobic protein-based HIPPEs, represented by zein.

The application of natural biopolymers to develop colloidal carriers for delivering hydrophobic bioactive molecules has become one of the hottest topics in food science. In this study, a simple pH-driven method to prepare whey protein nanofibrils stabilized zein nanoparticles was developed. The formation, structure, intermolecular interactions, rheological properties, in vitro digestion, and antioxidant activity of the nanoparticles were investigated. When the mass ratio of zein and whey protein nanofibrils was 1:0.8, the hydrodynamic diameter and zeta potential of the nanoparticles were 413 nm and - 25 mV, respectively. Transmission electron microscope photographs showed that the nanoparticles were a spherical core-shell structure. Fourier transform infrared spectroscopy and surface hydrophobicity measurements indicated that whey protein nanofibrils adsorbed to the surface of zein aggregates through hydrogen bonding and hydrophobic interactions. Differential scanning calorimetry tests confirmed the formation of nanoparticles improved the thermal stability of zein and whey protein nanofibrils. The nanoparticles exhibited less shear-thinning behavior with low apparent viscosity, and it can\'t be degraded in simulated gastric fluid but can be in simulated intestinal fluid. The antioxidant activity of the nanoparticles was increased by in vitro antioxidant assay when compared to whey protein nanofibrils. This new technology to develop zein-whey protein nanoparticles may be used for preparing nanoparticles of other similar hydrophobic food ingredients. And the findings of this study may provide a theoretical basis for preparation of nanoparticles as a nutrient delivery system.