3D Extrusion Printing and Post-Processing of Fibre-Rich Snack from Indigenous Composite Flour

This study focused on developing nutritious 3D-printed snacks from composite flour prepared from barnyard millet, green gram, fried gram, and ajwain seeds. The work evaluated extrusion printability of the high-fibre, high-protein composite flour. Optimised process parameters that gave best resolution and stability are nozzle diameter of 0.84 mm, nozzle height of 0.63 mm, printing speed of 2400 mm/min, extruder motor speed of 300 rpm, and movement speed of X/Y and Z axis of 6000 mm/min and 1000 mm/min, respectively. 3D-printed objects were post-processed by deep frying, hot-air drying followed by deep frying and microwave drying. With proximate analysis of the post-processed 3D-printed foods, we conclude that microwave drying could better retain nutrients, while ensuring minimal changes in colour and textural properties, as compared with other post-processing methods. All post-processed samples were acceptable in terms of sensory attributes; the developed snack has the potential to be commercialised. This work explains the successful development of nutritious 3D-printed snacks from diverse plant sources, importantly, with emphasis on the development of high-fibre foods with good consumer acceptance.