Elucidating the pH influence on pulsed electric fields-induced self-assembly of chitosan-zein-poly(vinyl alcohol)-polyethylene glycol nanostructured composites

Abstract

HypothesisThe high incompatibility of bio-based materials such as protein and polysaccharides require a series of modifications to develop stable microstructures effectively. By modifying the density and charge of surface residues, pulsed electric fields processing can improve inter/intramolecular interactions, compatibility, and microstructure of bio-based nanostructured composites. ExperimentIn this work, the impact of pulsed electric fields at a specific energy of 60–700 kJ/kg (electric field strength = 1.6 kV/cm) on self-assembly of zein-chitosan-poly(vinyl alcohol)-polyethylene glycol composite dispersion was investigated at pH 4.0, 5.7, and 6.8. FindingsSuperior complex coacervated matrices were assembled at pH 4.0 and 5.7 before and after pulsed electric fields treatment at a specific energy of 390–410 kJ/kg. The compact and homogenous behaviour was attributable to pulsed electric fields-induced alteration of functional group interactions in a pH-dependent manner. Irrespective of the pH, very high electric field intensity caused excessive system perturbation leading to severe fragmentation and poor development of coacervates. The crucial insights from this study reveal that the self-assembly behaviour and integration of biopolymer-based systems possessing different local charges can be enhanced by optimising pulsed electric fields processing parameters and the properties of the colloidal systems such as the pH.