Low energy, organic solvent-free co-assembly of zein and caseinate to prepare stable dispersions

Water-insoluble zein (corn prolamins) has great potential for use as delivery systems. In this study, stable zein nanoparticle dispersions were produced using a pH-cycle method to form complexes with sodium caseinate (NaCas) without using an organic solvent. NaCas was mixed with zein at pH 11.5 and the subsequent neutralization to pH 7.0 enabled the co-assembly of zein and NaCas. The mean hydrodynamic diameter of spherical nanoparticles was smaller than 100 nm based on dynamic light scattering, scanning electron microscopy, and atomic force microscopy. The nanodispersions were stable during 30-day storage at 4 degrees C. The freeze-dried sample showed excellent re-dispersibility. The current study showed the promise of this novel method to prepare zein nanoparticles for applications such as delivery systems. (C) 2015 Elsevier Ltd. All rights reserved.