Development of gastric digestion-tolerant plant protein-based nanoparticles: Fabrication, characterization, antioxidant activity, and stability

This study aimed to fabricate gastric digestion-tolerant plant protein-based nanoparticles and to assess their antioxidant activity and stability in relation to their characteristics. Soybean, rice, and walnut protein-based nanoparticles (SPNP, RPNP, and WPNP) with uniform distribution (PDI <0.25) and small particle size (<120 nm) were successfully prepared via high-intensity sonication. SPNP and WPNP were found to be stabilized through hydrophobic interactions. WPNP with lower molecular weight distribution demonstrated greatest antioxidant activity. Its high rigidity contributed to its strong thermal stability (95 °C for 10 h) and long-term storage stability (4 °C, 20 °C, and 40 °C for 3 month) with size varying within a range of 5 nm and fairly constant antioxidant activity. Moreover, all nanoparticles exhibited resistance to gastric digestion, showing slight SDS-PAGE alterations and maintaining their morphology in the gastric phase. Of these, SPNP and WPNP exhibited a faster release rate in the intestinal phase and having particles smaller than 200 nm in the micellar fraction. This study provides key support for the advancement of plant protein-based nanoparticles as delivery systems.