Fabrication of hollow versus solid nanoparticles via co-assembly of soy protein isolate and gliadin: Structural...

This study used an anti-solvent precipitation method combined with alkaline heat treatment to prepare hollow nanoparticles (HP) and solid nanoparticles (NP) from soy protein isolate-gliadin (SPI-Gli) mixtures at different ratios. The interactions and structural changes of SPI and Gli during the particle formation process were studied to clarify their functional characteristics and influence on the delivery of naringin (NAR). Results from FTIR, fluorescence spectroscopy, particle size, shell hydrophobicity, surface hydrophobicity, and TEM confirm that HP form hollow spheres with a distinctive hydrophilic-hydrophobic shell structure. Hydrogen bonds, disulfide bonds, and electrostatic interactions are all involved in the assembly process. In contrast, NP present as compact solid spheres, mainly stabilized by hydrophobic interactions, hydrogen bonds, and electrostatic interactions. The high specific surface area and porous hollow structure of HP enable more uniform dispersion in the solution, increase interface adsorption sites, promote the formation of a more uniform and ordered interfacial film, and significantly improve the emulsifying and foaming characteristics of SPI-Gli. When SPI:Gli = 2:1, HP showed the highest emulsifying activity (48.41%), emulsion stability (84.59%), foaming ability (66.67%) and foam stability (95.50%). The hydrophobic inner layer of HP provides hydrophobic binding sites for NAR, while an appropriate amount of Gli optimizes the porosity and mechanical stability of HP. The HP-SPI:Gli = 2:1 sample showed the highest encapsulation efficiency (92.35%), drug loading capacity (18.11 μg/mg), and bioaccessibility (73.93%). This research enhances the applicability of HP within the food domain, laying the groundwork for its implementation in nutrient delivery systems.