Enhancing emulsification properties of pea protein isolate: Impact of heat treatment and soy hull polysaccharides on conformational modification and stability

In order to investigate the effect of conformational change in pea protein isolate (PPI) on its emulsification properties, soy hull polysaccharides (SHP) were added to modify the conformation following heat treatment at 70-100 °C to improve emulsification. The results of UV and fluorescence spectroscopy indicated that the heat treatment exposed the amino acid residues to a more hydrophobic environment. The mean volume diameter (d_4,3) of PPI was reduced from 67.25 ± 3.31 to 45.50 ± 0.62 μm, and secondary structure of protein became more ordered. The addition of SHP enhanced the adsorption of protein at the oil-water interface and reduced the interfacial tension. Interestingly, SHP decreased the short-term (12h) thermal stability index (TSI) from 3.5 to 2.8 in PPI/SHP emulsion treated at 100 °C. These findings validated that heat treatment combined with SHP modification can improve the emulsification of PPI, which positively impacts the development of pea-based products for high temperatures applications.