Advances in sustainable food packaging applications of chitosan/polyvinyl alcohol blend films.

Researchers are addressing environmental concerns related to petroleum-based plastic packaging by exploring biopolymers from natural sources, chemical synthesis, and microbial fermentation. Despite the potential of individual biopolymers, they often exhibit limitations like low water resistance and poor mechanical properties. Blending polymers emerges as a promising strategy to overcome these challenges, creating films with enhanced performance. This review focuses on recent advancements in chitosan/polyvinyl alcohol (PVA) blend food packaging films. It covers molecular structure, properties, strategies for performance improvement, and applications in food preservation. The blend's excellent compatibility and intermolecular interactions make it a promising candidate for biodegradable films. Future research should explore large-scale thermoplastic technologies and investigate the incorporation of additives like natural extracts and nanoparticles to enhance film properties. Chitosan/PVA blend films offer a sustainable alternative to petroleum-based plastic packaging, with potential applications in practical food preservation.

Gelatin/poly(vinyl alcohol)-based functional films integrated with spent coffee ground-derived carbon dots and grapefruit seed extract for active packaging application.

Nanoparticles are attractive, functional additives with great potential to be applied in biomaterial and food packaging. However, these particles are not soluble in water, thus limiting their widespread application. Here, we report a facile fabrication of carbon dots (CDs) using the spent coffee ground as the carbon source through a hydrothermal method. The CD was added to the gelatin/poly(vinyl alcohol) (Gel/PVA) film and grapefruit seed extract (GSE) to prepare multifunctional packaging films. The functional films' physiochemical and functional properties and packaging application were investigated. The composite film showed good UV protection properties with a slight decrease in transparency. The composite film containing CD/GSE showed strong antioxidant activity, scavenging >38 % DPPH and 100 % ABTS radicals. The film also exhibited significant antibacterial activity against the foodborne pathogens Listeria monocytogenes and Escherichia coli, completely eradicating the growth of these bacteria within 9 h of exposure. The CD/GSE-incorporated Gel/PVA films were used for pork packaging. The films were able to enhance the pork shelf life by reducing the L. monocytogenes bacterial growth in meat by 2 Log CFU/mL lower than the control wrapping film. The multifunctional Gel/PVA films are expected to be used for the active packaging of meat products.

Fabrication of Antioxidant and Antimicrobial Pullulan/Gelatin Films Integrated with Grape Seed Extract and Sulfur Nanoparticles.

Biopolymer-based functional blend films were prepared using pullulan and gelatin with functional fillers of sulfur nanoparticles (SNPs) and grape seed extract (GSE). A mixture of pullulan/gelatin (1:1) produced a compatible but slightly translucent free-standing film. SNPs capped with enoki mushroom extract and GSE were added as functional fillers to improve the properties (physical and functional) of the pullulan/gelatin-based film. The addition of SNP and GSE significantly (p < 0.05) boosted the UV-light barrier, water vapor barrier, and oxygen barrier properties of the pullulan/gelatin films. The mechanical performance of the pullulan/gelatin-based films was slightly decreased (∼10%), whereas the addition of fillers did not significantly affect the hydrophobicity and thermal stability. The addition of SNP provided the antimicrobial function against foodborne pathogenic bacteria, L. monocytogenes and E. coli, while GSE provided a powerful antioxidant activity to the pullulan/gelatin-based film. Therefore, pullulan/gelatin-based composite films with better UV, water vapor, and oxygen barrier properties and enhanced antioxidant and antibacterial properties are expected to have high utility in active food packaging applications.

pH-responsive pectin-based multifunctional films incorporated with curcumin and sulfur nanoparticles.

pH-responsive pectin-based functional films have been prepared by incorporating curcumin and sulfur nanoparticles (SNP). FTIR and SEM results indicated that curcumin and SNP were uniformly dispersed in the pectin to form a well-developed composite film. Addition of curcumin and SNP significantly influenced the surface color and UV-blocking properties of the composite films. The composite films showed a higher water contact angle and thermal stability compared with the neat pectin film, however, the mechanical and water vapor barrier properties did not change significantly. The composite film exhibited antibacterial activity against E. coli and L. monocytogenes, and strong antioxidant activity. When applied to shrimp packaging, the film showed a pH-responsive highly distinctive color change from yellow to orange as the quality of the shrimp changed.