Electric field and heating uniformity of radiofrequency-induced gelation of 3D-printed fish mince with different infill densities: a computational study with experimental validation

Surimi is a fish-based paste that has been extensively utilized in food 3D printing. By altering the structure design, and the infill density of 3D-printed samples, the internal structure and texture can be customized to suit specific preferences. Radio frequency (RF) technology enables fast, volumetric heating, which accelerates surimi gel formation. However, varying infill densities in 3D-printed food can result in different electric field distributions, thereby affecting the heating uniformity. Therefore, this study links the infill density of 3D-printed food with the electric field distribution and examines the heating uniformity of surimi samples with four selected infill densities. COMSOL Multiphysics software was utilized to establish an RF heating model for surimi samples. Experiments of surimi with 100% infill density subjected to RF heating were conducted to validate the model on temperature distribution. Modelling results showed good agreement with the experimental results, with a surface temperature difference of < 5.6 °C. The model was then applied to 3D-printed surimi samples with varying infill densities (30%, 50%, 60%, 70%). The results indicated that the electric field intensity (EFI) was greater at both ends of the sample and weaker in the middle. As the infill density increased, the internal EFI decreased, and the heating uniformity initially increased before decreasing at higher densities. The optimal heating uniformity was found at 60% and 70% densities, with TUI values of 0.191 and 0.198, respectively. This study offers valuable insights into optimizing RF heating and 3D printing for surimi products.