Development and Application of Biodegradable PVA/NaCAS/Zeolite Composite Films for Active Packaging: A Case Study on Postharvest Preservation of Blueberries

In this study, biodegradable active packaging films were developed by incorporating natural zeolite (0, 2.5, 5, and 10% w/w) into a polyvinyl alcohol (PVA)/sodium caseinate (NaCAS) matrix, and their structural properties and postharvest performance for blueberries (Vaccinium corymbosum L. cv. Brigitta) were evaluated. Scanning electron microscope (SEM) revealed that the 5% zeolite film exhibited the most homogeneous dispersion, and mechanical tests showed it had a tensile strength of 16.7 MPa and an elongation of 137.3%. Postharvest trials demonstrated that the packaging type and storage duration significantly influenced fruit quality. By day 48, weight loss had reached 38.1% in the raw film and 35.1% in the 5% zeolite film. Oxygen concentration decreased to 4.0% in the raw film but was maintained at 8.7% in the 5% zeolite film, while CO₂ accumulation was 20.1% and 13.5%, respectively. The total sugar content at the end of storage was higher in the raw films (17.8%) compared to the 5% zeolite films (15.7%). Color analysis showed that the 5% zeolite films had higher brightness and chroma (C) while better preserving the fruit's natural matte appearance. These findings suggest that especially 5% zeolite-reinforced PVA/NaCAS films are promising biodegradable alternatives to conventional plastic films for extending the shelf life of perishable fruits such as blueberries. PRACTICAL APPLICATIONS: PVA/NaCAS/zeolite films were developed for blueberry protection. The mechanical properties slightly decreased with zeolite addition. 5zeo-CF has been proposed as a potential sustainable active packaging material.