Dual extrusion 3D printing of mashed potatoes/strawberry juice gel

Currently most of food printers apply one printhead to extrude a single or a mixture of multiple materials. Such a printhead cannot control the materials distribution in a drop-on-demand way, while a multi-extruder printer enables the fabrication of highly attractive multi-material constructs with higher geometric complexity. In this study, the effects of extruder offset and retraction on the printing behavior were firstly optimized, followed by the preliminary tests of two methods of dual extrusion 3D printing. Method A is to create a multi-part model and assign each of them to one extruder. Method B is to create a single part model and assign different roles to each extruder. Some constructs with different inside shape were created using Method A. Product hardness and gumminess increased linearly with mashed potatoes (MP) percentage but showed no correlation with inside shape. Porous samples with special texture were printed using Method B by varying infill levels. Total printing time, firmness, hardness and gumminess increased with infill levels, and a clear discrimination was observed by principle component analysis (PCA). This suggested that dual extrusion 3D printing enables the fabrication of attractive multi-material constructs and has a potential to tailor textural properties of samples through varying infill percentage.