Ultrasound-mediated fabrication of chickpea protein nanoparticles for stabilizing Pickering emulsions

This research investigated the impacts of various ultrasonic power (0, 150 W, 300 W, 450 W, 600 W) treatments on chickpea protein isolate (CPI) and their ability to stabilize Pickering emulsions. Ultrasonication initially reduced particle size before causing subsequent increase, with the smallest nanoparticles (150.13 ± 0.94 nm) achieved at 450 W, as confirmed by scanning electron microscopy. Structural characterization demonstrated that α-helix content initially increased then decreased, while β-sheet content showed the opposite trend. Similarly, absolute zeta potential values, intrinsic fluorescence intensity, and surface hydrophobicity all exhibited initial increases followed by subsequent decreases upon ultrasound treatment. At 450 W, nanoparticles improved emulsion stability, decreasing droplet size by 18.96 % and increasing absolute zeta potential to 50.53 ± 0.35 mV (p < 0.05). The emulsification activity index (26.67 ± 0.19 m²/g) and stability index (47.02 ± 1.01 min) were significantly improved (p < 0.05), along with a lower turbiscan stability index. Microscopic analysis revealed a more uniform droplet distribution and a denser interfacial protein layer in emulsions stabilized by nanoparticles treated at 450 W. Additionally, these emulsions displayed enhanced thermal and freeze-thaw stability. However, excessive ultrasonication (600 W) caused protein reaggregation, adversely affecting emulsion stability. These results indicate that moderate ultrasound treatment (450 W) effectively optimizes CPI nanoparticles properties, highlighting their potential as effective stabilizers for emulsion system in the food industry.