Insights into the structure-property relationships of biogel-based inks in 3D food printing: From hydrogels and oleogels to bigels.

Three dimensional food printing (3DFP) enables the on-demand fabrication of edible constructs with customizable geometries, textures, and nutritional profiles. Biogel-based inks (BGink), including hydrogels, oleogels, and bigels, provide a highly versatile platform, as their rheological and physicochemical properties can be systematically tuned to meet specific processing and functional requirements. This review critically synthesizes recent advances in biogel-based 3DFP through a multiscale structure-property-function framework. It compares the roles of molecular crosslinking and water confinement in hydrogels, oil-structuring networks in oleogels, and phase organization and interfacial coupling in bigels, linking these structural mechanisms to ink properties and macroscopic functionality. Building upon these colloidal and interfacial architectures, the discussion then connects formulation-dependent properties with key printing parameters to explain the shape fidelity, structural stability, and sensory-related and functional properties of printed structures. These structure-function relationships are further discussed in the context of representative applications, including personalized and functional foods, clinical and therapeutic diets, artificial intelligence integration, and sustainable biomanufacturing. Current limitations and future research needs are also identified. Overall, this review clarifies the multiscale relationships among biogel microstructures, ink properties, and end-product performance, providing a scientific foundation for the rational design of next-generation BGink and advanced 3DFP systems.