Development of active composite film based on chitosan-polyvinyl alcohol (PVA) blend containing basil essential oil and carvacrol nanoemulsions for enhanced packaging and shelf-life extension of toast bread

Sustainable preservation of bakery products motivates research into biodegradable active packaging. This study presents a novel polyvinyl alcohol-chitosan (PVA-Ch) active film incorporating basil essential oil nanoemulsion (BEN) and carvacrol nanoemulsion (CN) to extend toast bread shelf life. The primary strength lies in the synergistic combination of BEN and CN, demonstrating enhanced functionality compared to individual components. BEN and CN were prepared via ultrasonication, individually and in combination (C-BEN). The nanoemulsions exhibited favorable droplet sizes (229.2±6.1 to 406.2±7.9 nm), polydispersity indices, and ζ-potentials (−33.5±1.2 to −44.0±1.3 mV), indicating good colloidal stability. Incorporation of nanoemulsions significantly modified the film's physicochemical attributes, including increased surface hydrophobicity and flexibility, alongside reduced moisture content and water vapor permeability (p < 0.05). The C-BEN film exhibited superior antimicrobial activity against Escherichia coli , Staphylococcus aureus , and Aspergillus niger (p < 0.05). This correlated with reduced UV-Vis light transmission and increased opacity. Microstructural analysis revealed good polymer compatibility. X-ray diffraction and thermogravimetric analysis indicated enhanced crystallinity and thermal stability, while Fourier-transform infrared spectroscopy confirmed intermolecular hydrogen bonding. Crucially, in a 10-day bread storage study, the active films, particularly C-BEN, effectively retarded moisture loss, crumb hardening, and microbial proliferation, confirming their exceptional potential for preserving bakery product quality. • Active PVA/chitosan/essential oil nanoemulsions films were successfully fabricated. • Active films exhibited potent antioxidant and anti-fungal activity for packaged bread. • Active films significantly retarded bread staling kinetics and delayed mold spoilage. • A synergistic basil–carvacrol system enhanced film functionality and bread shelf life.