Development of a coaxial extrusion deposition for 3D printing of customizable pectin-based food simulant

A coaxial extrusion printhead was designed for 3D printing of pectin-based food simulants in which the inner flow is the food-ink and the outer a CaCl2 crosslinking solution. A series of cubic-shaped objects was successfully 3D printed by changing the printing parameters including the food-ink composition, the layer height, and the rate and CaCl2 concentration of the outer flow. The printed objects did not necessitate any incubation post-treatment because the gelation of the food-ink occurred during the printing. The mechanical properties of the printed object were correlated to their final Ca2+ concentration which can be controlled by the rate and CaCl2 concentration of the outer flow. A predictive model was established for determining the printing settings to print 3D objects with a priori defined texture. The layer height was recommended to be set in function of the food-ink swelling behavior. Finally, we compared objects printed by coaxial and simple extrusion methods. The compared objects had similar Young's moduli but their other properties including volume and final Ca2+ concentration, were considerably impacted by the printing method.