Improvement of zein-soybean lipophilic protein complex Pickering emulsion gel by controlling ultrasonic power: focus on stability mechanism

Ultrasound enhancement technology (120–360 W) was used to treat zein and soybean lipophilic protein (LP) complex nanoparticles, which were then used to stabilize Pickering emulsion gels. Appropriate ultrasound facilitated zein-LP interactions, leading to a more ordered, flexible, and stable complex protein structure. The particle size was reduced to 105.23 nm, and the contact angle was close to 90°, which promoted interfacial affinity. Ultrasound treatment at 240 W formed a denser microstructure of zein-LP complex emulsion gels, which also led to a more uniform distribution of emulsified oil droplets. The gel strength and water holding capacity were increased to 28.2 g and 87.3%, respectively. Meanwhile, the rheological properties, physical stability, and thermal stability of the emulsion gels were improved. In addition, ultrasound-enhanced zein-LP complex emulsion gels could be applied as ideal edible inks in 3D printing of self-supporting products with high resolution. Therefore, controlling ultrasonic power improves the stability of emulsion gels by promoting structural modifications and intermolecular interactions of complex protein nanoparticles. These findings provide a theoretical basis and technical guidance for understanding the stability mechanism of ultrasound-enhanced zein-LP complex emulsion gels, as well as for the construction and application of highly stable functional emulsion gels.