Grape By‐Products for Smart Packaging Films: Antioxidant, pH‐Sensitive, UV‐Blocking and Antimicrobial Properties for Food Preservation

ABSTRACT Grape by‐products, including seeds, skins and stalks, have garnered attention for the development of active and intelligent films due to their phenolic‐rich composition. These by‐products contain compounds such as carotenoids, flavonoids, phenolic acids, tannins and proanthocyanidins, which exhibit antimicrobial activity against a broad spectrum of both gram‐positive and gram‐negative microorganisms. They also possess antioxidant properties, UV‐blocking capabilities and pH‐sensing characteristics that, when applied to packaging, can extend the shelf life of food. Consequently, the development of films from grape by‐products is of particular importance. This review aims to summarize recent studies (2019–2024) on films made from grape by‐products, focusing on their UV‐blocking properties, biological activities and pH‐sensing responses. The potential application of grape anthocyanins in pH‐sensitive refrigerated packaging is noteworthy, making them suitable for use with meats and seafood. Grape seed extracts have demonstrated dual antibacterial effects against both gram‐positive and gram‐negative bacteria, exhibiting dose‐dependent behaviour alongside antioxidant properties. Additionally, films made from grape syrup, grape seed extract and bacterial cellulose displayed minimal UV transmittance while maintaining partial transparency. This review serves as a guide for future research on smart packaging utilizing grape by‐products and can also inform studies on other by‐products intended for smart packaging applications.