Schiff base crosslinking in biopolymeric food packaging films: Dynamic covalent chemistry for advanced food...

Biopolymeric films (BFs) offer sustainable packaging alternatives but face limitations in mechanical strength and moisture resistance. This review explores dynamic covalent chemistry via Schiff base reactions (SBRs) as a transformative strategy to enhance BFs. Crosslinking amino-rich biopolymers (e.g., chitosan, gelatin) with aldehyde donors (e.g., dialdehyde polysaccharides, plant aldehydes) improves film stability, barrier properties, and stimuli-responsive behavior. Plant aldehydes serve dual roles as crosslinkers and antimicrobial agents, enabling pH-triggered release to combat spoilage. Advances in polysaccharide/protein-based films demonstrate efficacy in preserving fruits, vegetables, and meats. Innovations like pH-sensitive indicators and respiration-triggered release underscore SBR-engineered films' versatility for active packaging. Challenges in scalability, safety, and industrial integration remain. This work provides a roadmap for next-generation packaging balancing performance, sustainability, and precision preservation.