Structure–property–function relationships in PVA films enriched with agro-waste bioactives: a design-oriented perspective for food packaging

The increasing demand for sustainable food packaging has driven the development of biodegradable polymer systems containing bioactive compounds derived from agro-food waste. Among such materials, polyvinyl alcohol (PVA) stands out due to its excellent film-forming ability, biodegradability, and compatibility with various functional additives. This review provides a comprehensive discussion and structural–functional design analysis of PVA-based films loaded with bioactive compounds extracted from agro-food waste, considering the structure-property-function relationships responsible for the effectiveness of the systems under examination. The introduction of functional additives, such as phenolics, anthocyanins, betalains, and tannins, causes changes in the structural arrangement of the PVA matrix owing to intermolecular hydrogen bonds formed between them. These transformations lead to specific material properties, such as mechanical, optical, and barrier properties. Thus, it is possible to achieve additional functionalities, including antimicrobial activity, antioxidant capacity, UV-blocking ability, and pH sensitivity. The practicality of the developed systems has been demonstrated in applications in real food models, where PVA-based films have shown promising performance. Despite these advances, challenges related to raw material variability, processing scalability, and stability of bioactive compounds remain. Nonetheless, this review highlights the potential of agro-food waste valorization in PVA-based systems and emphasizes the importance of a structure–property–function-driven design strategy for developing next-generation sustainable food packaging materials.