Functional modification of β-lactoglobulin-based emulsion ink enables 4D printing and dysphagia diet applications: A proof-of-concept study

This study developed a β-LG-RA-PC emulsion ink as a proof-of-concept system for 3D/4D food printing. It characterized pH, salt, temperature, and oxidation stability; yam powder optimized texture and printability. Optimal pH 3 yielded minimal droplet size (24.99 μm), high viscoelasticity (G' > G”), and strong deformation resistance (σ 0  = 6.614 Pa), due to the shift in stabilization mechanism from electrostatic repulsion to dominant steric hindrance and three-dimensional network formation. Na + enhanced deformation resistance (σ 0 up to 11.320 Pa) but reduced viscosity. Heating decreased viscosity while maintaining σ 0 and improving recovery. Yam powder at 15 %–20 % ( w / v ), enabled precise printing of complex 3D structures, increasing yield stress (σ 0  = 16.138 Pa) and consistency ( k  = 133.25 Pa·s n ) with pseudoplastic behavior ( n  = 0.26–0.42). A curcumin-NaHCO 3 system achieved controllable color changes, establishing a proof-of-concept strategy for personalized nutrition and functional 4D-printed foods.