The Effects of Fabrication Conditions on the Construction of Zein–Curdlan Composite Nanoparticles and Their Emulsifying Attributes

In this study, zein–curdlan (CU) composite nanoparticles were fabricated via an anti-solvent precipitation method. The effects of preparation parameters, including the mass ratio, reaction pH, and temperature, on the physicochemical properties and emulsifying attributes of the composite particles were systematically investigated. Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) analyses revealed changes in the local molecular environment and molecular organization following zein–CU association, while particle size, zeta potential, and surface hydrophobicity measurements further demonstrated fabrication-dependent changes in the physicochemical characteristics of the composite particles. As the CU ratio increased, the zeta potential decreased to −25.5 mV, accompanied by a reduction in surface hydrophobicity, suggesting a more hydrophilic CU-associated particle surface. At pH 8, the particles showed the smallest size among the pH series (244.6 nm), which may be related to enhanced zein deprotonation and interparticle electrostatic repulsion under the tested conditions. A preparation temperature of 40 °C produced the smallest particles and the most favorable emulsifying properties among the temperatures examined. Overall, this work provides evidence for the formation and emulsifying performance of zein/CU composite particles, broadening the application of plant protein–polysaccharide complexes in food-grade Pickering emulsion systems.