Researchers from the Singapore University of Technology and Design (SUTD) pioneered a new approach to chocolate 3D printing at room temperature without the need for a temperature control mechanism. It also allows for multi-material 3D printing and thus opens up a wider application in the food industry.
The new approach uses a cold-extrusion method instead of the conventional hot-extrusion technique. This offers a wide potential for 3D printing of temperature-sensitive food eliminating the strict temperature control needs.
Prevalent Chocolate 3D Printing Method
The prevalent chocolate 3D printing method operates on a hot-melt extrusion technique which is similar to how a common FFF 3D printing technology operates. This is the most widely used technique in 3D printed chocolates where the chocolate is required to be between the temperatures of 31oC to 36oC so that it can be melted and dispensed accordingly. While this method has its advantages in simplicity and accessibility, the narrow range of operating temperatures is highly restrictive and inflexible.
Conversely, cold extrusion does not require the manipulation of temperature as it depends solely on the rheology of printing ink that is added to chocolate at the operating temperature. However, due to the lack of inks possessing suitable rheological properties, cold extrusion in 3D printed chocolate has not been demonstrated to date.
Ci3DP – The Chocolate 3D Printing Method
To bridge this gap, researchers from SUTD’s Soft Fluidics Lab developed a new approach, named as ‘Chocolate-based Ink 3D Printing’ (Ci3DP), to print chocolate-based inks at room temperature by cold extrusion.
Using the Ci3DP approach, readily available chocolate products such as syrups and pastes were mixed with cocoa powder to alter the rheology of the ink. Chocolate-based inks with high concentrations of cocoa powders exhibited shear-thinning properties with high viscosity; the inks also possessed a toothpaste-like property that did not flow at rest.
Speaking about the new approach, Dr. Rahul Karyappa, lead author of the research paper said, “The simplicity and flexibility of Ci3DP offer great potential in fabricating complex chocolate-based products without the need for temperature control.”
Also, Principal Investigator, Assistant Professor Michinao Hashimoto from SUTD added, “Ci3DP is capable of fabricating customized food in a wide range of materials with tailored textures and optimized nutritional content. 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.”
Multi-Material Chocolate 3D Printing
Apart from just chocolate 3D printing, the research goes a step further and it also demonstrated multi-material chocolate 3D printing using a direct ink writing (DIW) 3D printer equipped with two dispensing syringes.
The team 3D printed a cone-shaped structure containing a chocolate syrup inside as a filling. In the process, referring to the above shared image, syringe-1 printed the cone-shaped structure in step-1. The empty space within the cone was filled with a chocolate syrup using another dispenser syringe-2 in the step 2. The outer shell of the cone was then completed by syringe-1 in the step-3 to get the final product.
The research thus demonstrated how simplistically this technology can be readily extended to multi-material food printing. Multi-material food objects consisting of a range of liquid materials as fillings such as milk-based products (e.g. cream and yogurt) can be fabricated in a sequential manner using multiple dispensers.
The research paper titled ‘Chocolate-based Ink Three-dimensional Printing (Ci3DP)’ is published in Scientific Reports, a leading open-access, a multidisciplinary journal from Nature Research.
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