Electrostatically self-assembled ternary nanoparticles loaded with sesamol reinforce gelatin/chitosan films with enhanced physicochemical properties for fresh-cut apple and banana preservation

Sesamol-WPI interaction elucidated to construct stable WPI/Sesamol/PC nanoparticles. • WSP@NPs were developed by pH-driven electrostatic self-assembly. • Hydrogen bonding and electrostatic interactions formed between NPs and GC matrix • WSP@NPs improved the physicochemical and release performance of GC films. pH-driven electrostatic self-assembly was used to fabricate sesamol-loaded whey protein isolate/pectin (WPI) nanoparticles, which were incorporated into gelatin/chitosan (GC) films to improve their gas barrier and antioxidant properties for fruit preservation. The highest encapsulation efficiency (77.1%) was obtained at a WPI-to-sesamol ratio of 10:1. SEM, AFM, FTIR, XRD and TGA indicated enhanced intermolecular interactions after nanoparticle incorporation. Consequently, the nanocomposite films exhibited higher tensile strength (14.3 ± 1.86 MPa), improved UV-blocking performance (65.5% for UVA and 96.4% for UVB), as well as enhanced thermal stability and water resistance. The nanoparticle system effectively retarded sesamol release, resulting in elevated antioxidant activity (DPPH: 78.6 ± 2.4%; ABTS: 84.1 ± 1.4%). Application to fresh-cut apples and bananas demonstrated that GC + 10%NPs films significantly delayed quality deterioration by reducing color change, weight loss, enzymatic browning, and firmness loss. Overall, the biodegradable nanocomposite films show strong potential for sustainable active food packaging.