Abstract: In this paper, composite nanoparticles of soy protein isolate (SPI) and anthocyanin (ACN) were prepared by covalent binding and used to stabilize Pickering emulsions. We measured the surface hydrophobicity of nanoparticles with different concentrations of anthocyanins. The emulsifying activity index (EAI), emulsion stability index (ESI), rheological properties and microstructure of the resulting Pickering emulsions were measured via chemical and instrumental analysis. The results showed that as the volume fraction of anthocyanin increased from 0% to 0.15%, the surface hydrophobicity of nanoparticles decreased from 18 174 to 8 945; the EAI of Pickering emulsions increased 127 m2/g, and the ESI by nearly 100%, which was accompanied by a significant improvement in the distribution of lipid droplets. In addition, the Pickering emulsions exhibited solid-like properties and were a typical non-Newtonian pseudoplastic fluid. We also found that droplet bridging in SPI-ACN composite Pickering emulsions occurred with the addition of anthocyanins, which will lay a theoretical basis for developing new Pickering emulsions in the food industry.

Key words: Pickering emulsion, rheological properties, cryo-scanning electron microscopy, confocal laser scanning microscopy