"Mud-sand structure"-Inspired synergistic reinforcement of gellan gum and xanthan gum on the 3D printing properties of protein-based high internal phase emulsions.

The application of high internal phase emulsions (HIPEs) in 3D food printing is often constrained by inadequate self-supporting property, cohesiveness, and printing accuracy. A robust interfacial film alone is insufficient to address these challenges. Inspired by the "mud-sand structure," this study prepared HIPEs with an oil phase content of 75% (v/v) using a composite emulsifier consisting of ovalbumin, tea polyphenols, and hyaluronic acid (Group C). To enhance interfacial strength and viscoelasticity, 0.3% gellan gum particles (Group G0.3) were incorporated into the aqueous phase as rigid fillers, together with varying concentrations of xanthan gum (GX series) as thickeners. Microstructural observations revealed that the addition of gellan gum and xanthan gum significantly improved the compactness and uniformity of the emulsion structure. Among all formulations, the GX0.6 group (containing 0.6% xanthan gum) exhibited the best overall stability, with centrifugal, static, and thermal stability all exceeding 98%, and the loss tangent (tan δ) significantly decreasing from 0.29 (Group C) to 0.12, indicating excellent viscoelasticity and self-supporting performance.In 3D printing tests, the incorporation of polysaccharides effectively improved the printability of the emulsions, enhancing cohesiveness and elasticity. The printing accuracy improved from a deviation of 100% in Group C to approximately 0% (within ±3% tolerance) in the GX0.6 and GX1 groups. All samples passed the IDDSI tests, demonstrating easy-to-swallow properties. In conclusion, the synergistic effect of physical support from gellan gum particles and thickening from xanthan gum overcomes the common drawbacks of poor self-supporting property and low printing accuracy of conventional HIPEs. The GX0.6 group achieves nearly perfect printing accuracy while maintaining high overall stability, providing a feasible strategy for developing 3D-printed foods suitable for individuals with dysphagia.