Synergistic effect of microwave 3D print and transglutaminase on the self-gelation of surimi during printing

To improve the molding quality of 3D printed surimi products under the disturbance of self-gravity and post-processing, the synergistic effect of a microwave 3D print (MW3DP) and transglutaminase (TGase) on the self-gelation process of surimi from fluid to solid gel state during 3D printing is investigated. Simulation and 3D printing results show that microwave power affected the extrudability by changing the temperature distribution of surimi in the nozzle. Rheological properties of the squeezed-out surimi were monitored while the gel properties, microstructure and self-gelation mechanism of products after printing were analyzed. Surimi exhibited shear-thinning behavior when microwave power was less than 60 W/g. After printing, the solid gels with better shape fidelity and large protein aggregates appeared at 40 and 50 W/g when TGase was added. Results indicate that hydrogen bonds and ɛ-(γ-Glu)-Lys are main forces to maintain molding quality, and TGase is activated by microwaves to promote the self-gelation process. 3D food printing, as an emerging technology in food industry, has great potential in meeting the individual needs of consumers for shapes and nutrition. One of the challenges that restricts the large-scale industrialization and commercialization of 3D food printing is that deformation will occur during printing and subsequent processing because most food materials are still flowing after printing. This study provided a synergistic method of MW3DP with a focused heating mode and TGase, realizing self-gelation of surimi during printing. A solid product with high resistance to deformation was obtained in this condition. Valuable guidance is provided to obtain heat-induced solid products with better shape fidelity. In addition, a more complex hollow shape can be printed to improve the personalization of food manufacturing, thus promoting further applications of 3D printing in food industry. •Synergy of MW3DP and TGase realized self-gelation of surimi during printing.•Gel strength of the printed products reached 327.80 ± 18.15 g·cm at 50 W/g.•Focusing heating mode of MW3DP boosted solid-like behavior of fluid surimi.•Hydrogen bonds and ɛ-(γ-Glu)-Lys are main forces to maintain molding quality.•MW3DP and TGase can be used for 3D printing of heat-induced gel food.