Abstract: In this paper, soybean protein isolate (SPI)-anthocyanin (ACN) covalent composite nanoparticles were successfully constructed and used to fabricate Pickering emulsions. The particle size, zeta potential, free radical scavenging ability, and optical microscopy of nanoparticles and Pickering emulsions were evaluated. The results showed that the particle size distribution and potential values of nanoparticles and Pickering emulsions were changed by adding anthocyanins. The comparisons showed that the nanoparticles and the emulsion systems became more stable after the addition of anthocyanins. In addition, the particle size distribution of the nanoparticles with 0.15% anthocyanins was uniform with the highest relative volume of particles; the absolute value of zeta potential was the largest and the abilities to scavenge free radicals were relatively strong. Microscopic observation showed that the droplet distribution of the Pickering emulsion with 0.15% anthocyanins was relatively uniform, and it was not easy to aggregate and relatively stable.

Key words: soy protein isolate, anthocyanins, Pickering emulsion, nanoparticles