Structure-function relationship and intelligent regulation of polysaccharide and protein-based hydrogels in food fresh-keeping packaging: A review.

Polysaccharide- and protein-based hydrogels possess good biocompatibility, abundant functional groups, and tunable network structures, making them sustainable materials for food packaging. Through the regulation of crosslinking, pore architecture, and intermolecular interactions, these hydrogels can achieve diverse packaging functionalities, ranging from basic barrier protection to active preservation and even intelligent regulation. This review focuses on how the structure-function relationships of hydrogels realize specific packaging functionalities and comparatively discusses four representative morphologies: coatings, films, absorbent pads, and microspheres. The discussion covers the transition from matrix-dominated passive barrier functions to additive-enabled active preservation, and finally to stimuli-responsive systems. It further elucidates how precise structural regulation in these functional systems impacts key preservation behaviors, such as moisture control, gas permeability, antimicrobial activity, and controlled release. Building on these structure-function principles, this paper further introduces data-assisted strategies for hydrogel food packaging, showing their potential in accelerating formulation screening, predicting transport behavior, and reducing trial-and-error costs.