Structuring wheat dough using a thermomechanical process, from liquid food to 3D-printable food material

In extrusion printing, the printability of food materials depends on the rheology of the food under shearing when extruded, and at rest, post-deposition. Piloting food microstructure to provide rheological properties compatible with 3D extrusion printing is a major challenge. Microstructure, rheology, and printability of wheat-flour based materials with varying concentrations of flour, sugar, oil, and water were studied. Materials were obtained by heating and shearing doughs with a moisture content above 55% (wb). The processed doughs were structured as closely-packed particles made of swollen gelatinized starch granules glued in a denatured proteins network. These materials were easily extruded in self-supporting layers by a 3D food-printer and formed stable objects with precise dimensions. The water/flour ratio played a crucial role in the structure of the wheat materials, impacting the storage modulus (G’), tan δ and printability. This work highlights the importance of tan δ in predicting the ability of food materials to hold its 3D structure.