Structure–Property Relationships in Bioactive Poly (Vinyl Alcohol) Films Incorporating Natural Phenolic Additives for Sustainable Active Packaging

This study aimed to investigate bioactive poly (vinyl alcohol) (PVA) films incorporating three chemically distinct naturally phenolic additives—aronia extract (A), apple peel extract (AP), and rutin (R)—as individual functional modifiers for active packaging applications. Here, we studied how the chemical nature of these phenolic compounds influenced the physicochemical characteristics, structure, release behavior, and functional properties of the PVA matrix. The FTIR, SEM, AFM and XPS analyses revealed intermolecular interactions between the hydroxyl groups from the PVA matrix and the hydroxyl and carboxyl groups from phenolic compounds, a high degree of miscibility between them, as well as uniform dispersion of polyphenols in the PVA matrix. XRD analysis indicated the ability of phenolic compounds to change the PVA film’s crystallinity. The films showed very low permeability to castor oil and the UV-Vis light barrier property of the film modified with aronia extract was 47% higher as compared to the reference film. The phenolic compounds improved the antioxidant activity of the reference film by about 90% and inhibited the growth of Gram-positive Staphylococcus aureus. The modified films proved their functionality by keeping the quality of the butter packed for 43 days, demonstrating their potential as active packaging materials.