Extrusion-based food printing for digitalized food design and nutrition control

Differentiated from food extrusion cooking, extrusion-based food printing is a digitally-controlled extrusion process to build up complex 3D food products layer by layer. It is the most popular method in food printing, which provides an engineering solution for digitalized food design and nutrition control. The objective of this study was to collate, analyse and categorize published work pertaining to the extrusion-based food printing technique in order to determine its impact on food texture design and identify any related technical bottlenecks. Currently, for food printing, the applied printing stages include Cartesian, Delta, Polar and Scara configurations, and three extrusion mechanisms, namely syringe, air pressure, and screw, are utilized. This paper provides a detailed discussion regarding these factors and the parameters associated with the extrusion and printing processes. A comparison between specialized food printers and 3D printers with food printing functions is reported in terms of food safety and system design complexity. Temperature control plays an important role in both food extrusion and post-deposition cooking, and the commercial food printers are reviewed based on temperature control methods, printable materials, extrusion mechanism and final products. Then, a comprehensive analysis to innovate food design is reported, based on layer structure, unique appearance, post deposition cooking, recipe reformulation and digitalized nutrition control. Finally, market challenges, technical difficulties and possible strategies along the pathway of commercialization are discussed.