Polysaccharide/protein based composite systems for strawberry preservation: Bio-based materials, enhanced functionality, and quality maintenance

Strawberries are widely cultivated berries appreciated for their rich nutrition and pleasant flavor. However, their postharvest quality deteriorates rapidly due to vigorous respiration, fragile peel, and susceptibility to microbial infection. Traditional packaging extends strawberry shelf life but raises serious environmental concerns. Its low gas permeability causes moisture condensation on the uneven fruit surface, promoting microbial growth and decay. Moreover, microplastic particles enter the flesh through natural stomatal channels in the peel or via endocytosis of peel cells. Therefore, developing bio-based composite packaging films based on bio - based materials has become a research hotspot in food preservation. This review systematically summarizes the progress of bio - based composite packaging films for strawberry preservation, focusing on biomaterial sources, enhanced functionalities, and effects on strawberry quality. First, the film-forming properties and limitations of polysaccharide - and protein - based materials are summarized. Second, the performance improvements of polysaccharide - protein composite systems loaded with active substances are reviewed. Finally, the preservation effects are evaluated in terms of maintaining physical and nutritional quality of strawberries, and the application of omics technologies to reveal molecular preservation mechanisms is introduced. Despite these advances, challenges such as cost control, and safety evaluation still hinder commercial application. This review aims to provide a theoretical reference for the research and development of bio - based composite packaging films for strawberry preservation and to lay a foundation for promoting the industrial application of sustainable food packaging materials.