Physicochemical processing techniques for the preparation and functional regulation of biopolymer-based packaging films: A review

Biopolymer-based packaging films are essential components in food industrial production. However, conventional synthetic films based on polyvinyl chloride and polystyrene suffer from poor biodegradability, lack of antimicrobial activity, and an inability to monitor food freshness in real time, highlighting the urgent need for alternative materials. Meanwhile, packaging films fabricated solely from untreated natural polymers generally fail to meet the performance requirements for large-scale food applications. This review systematically summarizes the mechanisms of physical, chemical, and enzymatic treatments in the preparation and functional regulation of polymer-based food packaging films. The effects of different processing strategies on molecular interactions, polymer chain arrangement, network structure, physicochemical properties, and preservation performance are critically discussed. Furthermore, recent advances in the synergistic application of physical and chemical approaches are highlighted, aiming to provide theoretical insights and guidance for the development of advanced food packaging materials. Biopolymer-based packaging films derived from natural polymers have attracted increasing attention due to their inherent biodegradability. Existing studies indicate that physical field-assisted treatments can regulate polymer chain rearrangement, intermolecular hydrogen bonding, and crystallinity, thereby improving film compactness, barrier properties, and mechanical performance. Meanwhile, targeted chemical modification strategies can confer antimicrobial activity and environmental responsiveness through functional group regulation, crosslinking reactions, and network reconstruction. Notably, the synergistic integration of physical and chemical approaches has emerged as an important direction in functional food packaging, enabling intelligent indicator properties and real-time monitoring of freshness changes during food storage.