Abstract: The present study was undertaken to explore the effect of ultra-high pressure (UHP) processing the formation of emulsions containing soy protein and soluble polysaccharide complexes and to reveal the relationship between the structural change and emulsion stability of the complexes. For this purpose, the changes in the microstructure, particle size distribution, interfacial adsorption properties and spatial structure of soy protein after UHP modification were studied using confocal laser technology, dynamic laser light scattering, contact angle measurement and circular dichroism. The experimental data showed that the droplet size of the emulsion became smaller, more regular in shape and more evenly distributed with increased pressure and the negative surface charge increased. UHP treatment at 400 MPa provided the maximum emulsifying activity and emulsion stability, which were 18.33 m2/g and 30.2 min, respectively. The secondary structure of soy protein changed after UHP treatments, thereby influencing its bonding with soluble polysaccharides and the adsorption properties of protein at the oil-water interface and the interface pressure of the emulsion. These results uncovered that the stability mechanism of emulsions containing ultra-high pressure-modified soy protein and soluble polysaccharides may related to the change in the molecular structure of the interfacial layer in emulsions.

Key words: ultra-high pressure treatment, flexible protein, soluble polysaccharide, stability