Tailoring 3D-printed gelatin-based high internal phase emulsions for enhanced resveratrol delivery: Role of gelatin type, pH, and concentrations.

This study systematically investigated the effects of gelatin (GE) type (GEA/GEB), concentration, and pH on the properties of high internal phase emulsions (HIPEs). Self-supporting HIPEs with 82 vol% oil loading were achieved at GE concentrations above 3%. Increasing GE content promoted interfacial adsorption, denser films, yielding smaller droplets and tighter packing, which enhanced structural integrity, thermal stability, viscoelasticity, and thixotropy. GEA demonstrated superior performance due to greater hydrophobicity and surface activity, forming a robust 3D network at the interface via irreversible adsorption, bridging, and steric effects. In contrast, GEB favored aqueous-phase gelation, imparting less favorable printing rheology. Emulsions were destabilized under extreme pH. HIPEs with 7% GEA showed excellent 3D printability and shape fidelity, and offered enhanced protection for resveratrol against thermal/UV degradation, enabling controlled intestinal release. This work highlights GEA-stabilized HIPEs as advanced edible inks for precision printing and targeted nutrient delivery.