Researchers from the Singapore University of Technology and Design (SUTD) have developed a method perform direct ink writing (DIW) three-dimensional (3D) printing of milk products at room temperature by changing the rheological properties of the printing ink.
3-D printing of food has been achieved by different printing methods, including the widely used selective laser sintering (SLS) and hot-melt extrusion methods. However, these methods are not always compatible with temperature-sensitive nutrients found in certain types of food. For instance, milk is rich in both calcium and protein, but as these nutrients are temperature sensitive, milk is unsuitable for 3-D printing using the aforementioned printing methods which require high temperature. While the cold-extrusion is a viable alternative, it often requires rheology modifiers or additives to stabilize printed structures. Optimizing these additives is a complex and judicious task.
To tackle these limitations, the research team from SUTD’s Soft Fluidics Lab changed the rheological properties of the printing ink and demonstrated DIW 3-D printing of milk (refer to image) by cold-extrusion with a single milk product—powdered milk. The team found that the concentration of milk powder allowed for the simple formulation of 3-D-printable milk inks using water to control the rheology. Extensive characterizations of the formulated milk ink were also conducted to analyze their rheological properties and ensure optimal printability.
Given the versatility of the demonstrated method, they envision that cold extrusion of food inks will be applied in creating nutritious and visually appealing food, with potential applications in formulating foods with various needs for nutrition and materials properties, where food inks could be extruded at room temperature without compromising the nutrients that would be degraded at elevated temperatures.
References: Cheng Pau Lee et al, 3D printing of milk-based product, RSC Advances (2020). DOI: 10.1039/D0RA05035K link: https://pubs.rsc.org/en/content/articlelanding/2020/RA/D0RA05035K#!divAbstract