Enhancing the usability of pea protein in emulsion applications through modification by various approaches: A comparative study

The extensive utilization in food industry of pea protein is often impeded by its low water solubility, resulting in poor functional properties. Various methods, including pH-shifting (PS), ultrasonication (US), high-pressure micro-fluidization (MF), pH-shifting combined with ultrasonication (PS-US), and pH-shifting with micro-fluidization (PS-MF), were utilized to modify pea protein isolate (PPI) in order to enhance its functionality in emulsion formulation. The physicochemical properties and structural changes of the protein were investigated by assessing solubility, particle size, surface charge, protein profile, surface hydrophobicity, free sulfhydryl groups, and secondary structure content. The extent of modification induced by each treatment method on PPI-stabilized emulsions was compared based on parameters such as adsorbed interfacial protein concentration, particle size, zeta potential, and microstructure of the prepared emulsions. All modification increased the solubility of pea protein in the sequence of PS (4-fold) < MF (7-fold) < US (11-fold) < PS-US (13-fold) < PS-MF (14-fold). For single treatments, proteins dissolved more readily under US, resulting in the most uniform emulsions with small particle. The combined processes of PS-US and PS-MF further improved solubility, decreased emulsions particle size, promoted uniformity of emulsions. PS-US-stabilized emulsions displayed more smaller droplet size, narrower size distribution, and slightly higher stability than those prepared by PS-MF. The relatively higher emulsifying capacity of PPI treated by PS-US than those by PS-MF may be attributed to its higher surface hydrophobicity.