Food Gels: From Molecular Gelation Mechanisms and Multiscale Structures to Functional Applications

Food gels are soft materials in which three-dimensional (3D) networks of proteins, polysaccharides, lipids, or their composites immobilize water, oil, or gas and provide tunable rheological, mechanical, and functional properties. Performance assessment remains inconsistent across studies, as researchers often report gel strength or water-holding capacity alone and rarely compare different gel systems using common criteria. The assumption that denser networks perform better also remains largely untested. This review organizes the field around a cross-scale pathway from external triggers and intermolecular interactions to mesoscale networks and macroscopic functions. It applies this framework to hydrogels, oleogels, and bigels and links their preparation methods to multiscale characterization. Network densification does not necessarily improve performance: it may enhance water-holding capacity and barrier properties but also restrict flavor release, reduce enzyme accessibility, and compromise swallowing safety. Therefore, the optimal network structure should be defined for each application rather than maximized. These trade-offs are relevant to delivery systems, fat replacement, 3D printing, edible coatings, and intelligent indicators. Future research should establish unified structure–digestion–sensory metrics, validate data-driven models externally, and test gel performance under realistic storage and use conditions.