Microwave-induced deformation behaviors of 4D printed starch-based food products as affected by edible salt and butter content

Due to increased interest in directional deformation of 3D printed products, any novel means to induce such a deformation is of interest. Here, microwave dehydration as external stimulus was applied to prepare 4D printed starch-based food products with directional bending deformation. First, the effects of solid content of purple sweet potato paste (PSPP) and mashed potato (MP) were investigated; such the solid content positively correlated with the apparent viscosity, G and yield stress, but negatively correlated with T2 relaxation time of the pastes. The solid content of 30% was identified as the most appropriate for subsequent directional deformation experiments. The effects of edible salt and butter content on dielectric properties and bending angles of the printed products were determined. Increased edible salt and butter content significantly reduced the bending angles of PSPP and MP. In addition, the bending angles of MP were higher than those of PSPP at the same conditions. Industrial relevance: This study provides ideas for controlled deformation of 3D printed objects; microwave dehydration was selected as a stimulus that can be conducted even in a small industry or at a household level. These procedures would allow the creation of foods with attractive appearances for consumption at either a restaurant or at home. The proposed technique should also lay a foundation for further application of 4D food printing.