Physical-Field Engineering of Food Hydrogels: Multiscale Assembly, Processing Windows, and Functional Translation

Food hydrogels are multiscale, water-rich networks whose functionality depends not only on composition but also on how processing energy is deposited and redistributed during network formation. Although acoustic, electric, magnetic, and pressure-based treatments have expanded the available strategies for hydrogel structuring, current evidence remains fragmented by inconsistent dose reporting, thermal and electrochemical confounding, strong matrix dependence, limited validation in compositionally realistic foods, and insufficient scale-up and safety assessment. This review critically evaluates these technologies through a field-process-structure-function framework that links measurable field inputs and energy deposition to molecular and colloidal reconfiguration, network architecture, water mobility, and food functionality. Across the available literature, ultrasound has the broadest evidence base for precursor restructuring and gel network modification, while high-pressure processing shows comparatively strong support for direct gelation and composite network reinforcement. Electric-field approaches offer controllable electrothermal and directional effects but require more rigorous separation of field-specific contributions from thermal and electrochemical effects. Magnetic and conductive edible hydrogels remain comparatively early-stage, with much of the mechanistic evidence still derived from non-ingestible systems. Overall, beneficial responses occur within matrix-specific processing windows rather than increasing monotonically with treatment intensity. Future progress requires matched controls, quantitative dose reporting, realistic food matrices, food-grade safety validation, continuous-processing equipment, and energy-normalized assessment of technological feasibility.