The effect of D-allulose as a sugar substitute and salt reduction on the printability and physicochemical quality of 3D printed Atlantic cod (Gadus morhua) surimi

Increasing demand for full utilization of fish processing side-streams has driven the development of innovative surimi-based products. Salt and sugar are commonly used as stabilizers and cryoprotectants in surimi. However, high intake is associated with health concerns, highlighting the need for alternative formulations. This study investigated the feasibility of developing 3D printable surimi materials with reduced salt concentrations (0, 0.50, 0.75 and 1.50% NaCl wet weight) and the alternative cryoprotectant d -allulose as a sugar replacement, and evaluated their effects on printability, structural stability, physicochemical properties, and water distribution of the printed gels. All formulations were successfully extruded, and the incorporation of d -allulose improved extrusion behavior and layer formation. All samples maintained their structural integrity without collapsing during printing and maintained good structure fidelity during cooking. Salt reduction decreased the gel strength and mechanical properties, however, the d -allulose effectively compensated for these effects by enhancing hardness, chewiness, and overall gel stability in the cooked 3D printed surimi. Cooking loss increased with decreasing salt concentration, whereas water-holding capacity remained relatively stable across all formulations. Color changes were mainly influenced by thermal processing rather than formulation differences. Low-field Nuclear Magnetic Resonance (LF-NMR) analysis revealed increased water restriction after cooking due to protein denaturation and gel network formation, while d -allulose slightly improved water retention and contributed to a more stable gel structure. Overall, the results demonstrate that low-salt 3D printed surimi products can be successfully developed without compromising structural integrity. d -allulose showed strong potential as a functional ingredient to enhance printability, gel strength, and water retention, supporting the development of healthier and value-added products from fish processing side streams.