Abstract: In this paper, whey protein isolate-tannic acid (WPI-TA) nanoparticles were prepared by alkaline method. The effect of the mass ratio of WPI to TA on the formation of WPI-TA nanoparticles was investigated by measuring the particle size and potential. Then, the optimal WPI-TA nanoparticle was selected as the emulsifier to prepare rice bran oil Pickering emulsion by a simple shear-induced emulsification technique. The impact of the interaction between WPI and TA was investigated on the thermal, ion and oxidative stability of rice bran oil Pickering emulsion. At the same time, the stability mechanism of the Pickering emulsion was explored. The results implied that WPI-to-TA ratio affected the formation and stability of WPI-TA nanoparticles. Besides, Fourier transform infrared spectroscopy showed that the interaction between WPI and TA caused a change in the secondary structure of the protein. The introduction of TA significantly increased the emulsification activity of WPI-TA nanoparticles, improved the stability of the Pickering emulsion to temperature and ionic strength while inhibiting the formation of primary and secondary oxides during storage. Therefore, WPI-TA nanoparticles are expected to be a potential advantageous stabilizer for Pickering emulsion.

Key words: whey protein isolate; tannic acid; interaction; Pickering emulsion; stability