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 (σ0 = 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 (σ0 up to 11.320 Pa) but reduced viscosity. Heating decreased viscosity while maintaining σ0 and improving recovery. Yam powder at 15 %-20 % (w/v), enabled precise printing of complex 3D structures, increasing yield stress (σ0 = 16.138 Pa) and consistency (k = 133.25 Pa·sn) with pseudoplastic behavior (n = 0.26-0.42). A curcumin-NaHCO3 system achieved controllable color changes, establishing a proof-of-concept strategy for personalized nutrition and functional 4D-printed foods.