Development and characterization of dialdehyde cellulose nanocrystal–vanillin functionalized gelatin/chitosan composite films for blueberry preservation

Bio-based composite films offer opportunities for postharvest fruit protection, although their practical performance requires careful evaluation. Dialdehyde cellulose nanocrystals (DACNC) and vanillin (VA) were incorporated into a gelatin/chitosan (Gel/CS) matrix. Structural analyses indicated changes in chemical environments consistent with possible interfacial interactions, but did not independently confirm Schiff-base formation. The formulation containing DACNC and VA at a mass ratio of 1:3 (CGDV1) was selected for exploratory blueberry preservation evaluation. CGDV1 showed a tensile strength of 34.72 MPa and an elongation at break of 24.74%, together with enhanced ultraviolet shielding and composition-dependent water-related properties. The CGDV1 film-forming solution showed radical-scavenging activity, whereas the antioxidant performance of the final dried film was not directly evaluated. Representative antibacterial plates showed visually lower colony density for CGDV1, but these observations were qualitative and lacked independent biological replication. The CGDV1 film-forming solution maintained L929 cell viability above 80% at solid-equivalent concentrations of 15.6–125 µg/mL. During storage at 26 ℃, CGDV1-treated blueberries showed comparatively better visual appearance and a lower descriptive weight-loss trend than the water-treated control. These preservation observations were preliminary because independent biological replication was lacking and storage relative humidity was neither controlled nor monitored. These findings support CGDV1 as a candidate bio-based coating, with further validation needed through independently replicated storage experiments under controlled conditions.