3D printing chocolate is nothing new. We’ve seen ample examples of extrusion-based technologies depositing melted chocolate layer by layer to build up all kinds of simple shapes. Recently, however, a team from the Singapore University of Technology and Design (SUTD) has made a breakthrough in chocolate 3D printing, moving away from heated printing processes to a cold extrusion approach.
The technique devised by the team essentially allows for chocolate to be 3D printed at room temperature, which overcomes several limitations associated with hot-melt extrusion. The novel and mouth-watering technology, developed by a team from SUTD’s Soft Fluidics Lab is called Chocolate-based Ink 3D Printing or Ci3DP.
As opposed to hot-melt extrusion, which relies on hot temperatures to keep the printing material viscous, cold extrusion depends on the rheology of printing ink—that is to say, the flowability of the material—at the operating temperature.
In the Ci3DP process, chocolate products (such as syrup or paste) were mixed with cocoa powder to change the rheology of the ink. The more cocoa powder was added, the higher the shear-thinning properties and viscosity. In texture, the cocoa-loaded inks were not unlike toothpaste, in that they stopped flowing at rest.
The simple approach was demonstrated by the SUTD team by 3D printing models made from syrup and paste-based inks. Chocolate morsels with varying textures were also printed using a combination of the different inks. For example, the team 3D printed a semi-solid enclosure and a liquid filling at the same time. (The question of how the caramel is put in the Caramilk bar takes on a whole new dimension!)
Dr. Rahul Karyappa, the lead author of the study at SUTD, commented on the novel technology, saying: “The simplicity and flexibility of Ci3DP offer great potential in fabricating complex chocolate-based products without the need for temperature control.”
Typically, in the hot-melt extrusion process for chocolate, temperatures must be maintained between 31 and 36 degrees Celsius—a narrow range which can be challenging to control and restrictive. With cold extrusion, however, the process is untethered from the temperature restrictions.
“Ci3DP is capable of fabricating customized food in a wide range of materials with tailored textures and optimized nutritional content,” added Michinao Hashimoto, Principal Investigator and Assistant Professor at SUTD. “This new approach also widens the industry’s capabilities in 3D food printing, allowing for the cold-extrusion of food products that are temperature sensitive.”