Sealable PLA+quercetin coatings on biodegradable PBS/PVOH films for food packaging: Release kinetics, antioxidant activity and shelf-life extension potential

In this study, a coating-based strategy was employed to develop biodegradable multifunctional films with heat sealable properties and antioxidant activity, for food preservation applications. The films consisted of a blown substrate, made of poly(butylene succinate) (PBS) and poly vinyl alcohol (PVOH) blend, previously optimized to achieve good processability, mechanical performance and barrier properties, coated with a sealable polylactic acid (PLA) layer enriched with quercetin (QUE) at different concentrations (3%, 5%, 7% wt/wt). FTIR analyses highlighted concentration-dependent QUE–PLA physical interactions, which contributed to modulating the release profiles but slightly decreased seal strength. The release kinetics and antioxidant performance of the films were evaluated both in fatty (95% ethanol) and aqueous (10% ethanol) food simulants. Antioxidant activity was markedly higher in fatty simulant - where the BS/PLA+ 7%QUE film reached the maximum release (101.7 mg/L) - while in aqueous system a slower and more sustained release was observed. Mathematical modeling confirmed the different migration mechanisms, dominated by polymer–active interactions in aqueous environment and by cooperative processes in ethanol-rich simulant, providing insights useful for design optimization in specific applications. Oxygen permeability and overall migration measurements confirmed that the active coating did not compromise barrier performance, while complying with EU Regulation No. 10/2011. Shelf-life tests on fresh-cut avocado slices demonstrated that the BS/PLA+ 7%QUE film effectively reduced browning and preserved pulp texture. Overall, the proposed PLA–QUE coated PBS/PVOH system represents a promising biodegradable antioxidant packaging solution integrating barrier performance, heat-sealability, and tailored release to extend the shelf life of perishable foods.