Researchers from Singapore University of Technology and Design have developed a method for 3D printing food without using food thickeners. In their paper, they discussed a method of direct ink writing (DIW) 3D printing on okara (a byproduct of soybean milk and tofu) without the use of rheology modifiers. Related papers were recently published in "American Chemical Society-Food Science and Technology".
Nowadays, 3D printing has become an emerging technology that can use computers to design foods of various shapes. In this process, food additives (usually hydrocolloids and food thickeners) are added to the food to achieve 3D printing and maintain the printing structure. However, the use of additives may cause unexpected changes in the texture and taste of the original food.
Snacks of various shapes and sizes printed with Okara 3D
（Image source: Singapore University of Technology and Design）
In order to overcome this challenge, the research team of the Soft Fluid Laboratory of Singapore University of Technology and Design determined a specific particle size and concentration of Okara. Okara is the main by-product of soybean processing. Although it contains a lot of dietary fiber and protein, it is usually discarded in the food production process. In order to achieve the "ink" properties of the desired food, the researchers reused the discarded bean dregs. Their test results show that particle size is an important variable that determines the rheological properties of "ink". They characterized the okara "ink" of different formulations and analyzed their rheological and structural properties. The measurement results show that the particle size is a basic variable that determines the rheological properties of Okara ink. The research team demonstrated a 3D printable okara ink. The weight percentage of okara powder is 33%, the particle size is <100μm, its yield stress is 200±40Pa, and the storage modulus is 23300±300Pa. The researchers finally produced a controllable texture snacks.
The lead researcher and associate professor of the school, Michinao Hashimoto, explained: "Our research highlights that'junk' food can be upgraded and recycled, and food with custom attributes can be achieved through 3D printing. We believe that this research is improving food design for the realization of 3D printing technology. And pave the way for the full potential of sustainable development."
The author stated that making full use of these underutilized nutritious foods will promote the sustainability of food supply and reduce food waste. Researchers plan to develop more "inks" made from other food residues to promote the sustainable development of food.
Related paper information: https://doi.org/10.1021/acsfoodscitech.1c00236