Development of composite film based on polyvinyl alcohol with binary nanoreinforcements for active packaging of fresh-cut apples

To develop a sustainable and environmentally-friendly preservation packaging for fresh-cut fruits and vegetables (FFV), this study synthesized the nanohybrid LDH@PCA using layered double hydroxide (LDH) loaded with p-coumaric acid (PCA). Subsequently, the nanohybrid and lignin nanoparticles (LPs) were integrated into a polyvinyl alcohol (PVA) matrix to prepare a binary nanocomposite packaging material named PVA-LPs-LDH@PCA. In this case, LDH@PCA and LPs were homogeneously dispersed inside PVA, relying on hydrogen bonding at 3 % (w/w) and 5 % (w/w), respectively, while electrostatic attraction also played a role. The reinforcement of the binary nanomaterials led to a significant increase in the radius of gyration and mass fractal dimension of the microregions within the PVA films. Additionally, the tensile strengths were 66 %, 32 %, and 8 % higher than those of the PVA, PVA-LPs, and PVA-LDH@PCA films, respectively. Moreover, the binary nanocomposite packaging exhibited enhanced water vapor, oxygen, UV barrier, and thermal stability, while synergistically improving its antioxidant activity compared to the aforementioned films. Remarkably, PCA in PVA-LPs-LDH@PCA demonstrated sustained release properties, consistent with Avrami and Arabolic diffusion models, for up to 55 h. Packaging of fresh-cut apples with PVA-LPs-LDH@PCA effectively maintained the texture, appearance, and nutritional quality. Transcriptomic and metabolomic analyses revealed that this packaging inhibited cell wall degradation, maintained cell membrane integrity, stimulated scavenging of reactive oxygen species, and inhibited polyphenol oxidase, attenuating the adverse effects of water loss stress on fresh-cut apples. These findings suggest that PVA binary nanocomposite films hold great potential as a sustainable solution for freshness preservation in FFV packaging.