Sorghum proteins offer resilient 3D printable ‘bioink’ base

Food scientists are paving the way for 3D-printed food and pharmaceuticals based on drought-tolerant grain sorghum protein that won’t turn into a blob.

The grain, which is capable of growing in contrasting climatic conditions, is also known for its health benefits, such as inhibiting inflammation and reducing heart disease risk by lowering total cholesterol levels and increasing antioxidant potential with unique phenolic compounds. It is also a gluten-free cereal grain.

Ali Ubeyitogullari, an assistant professor of food engineering with the food science and biological and agricultural engineering departments, has already shown that sorghum flour can be made into a “bioink” for 3D printing cookies. The next step, he said, was to optimize printable sorghum proteins for novel food and medicine production.

Sorghum proteins have been used in meat substitutes and 3D food printing to make more realistic recreations of beef steaks, for example. The proteins from grain sorghum are also used in protein bars and baked products.

What makes sorghum proteins particularly useful in 3D food printing is their hydrophobicity (ability to repel water) to aid in product cohesion.

Many food materials, especially starches and proteins, are hydrophilic and readily absorb water, which limits the incorporation of hydrophobic components into the formulation, Ubeyitogullari explained.

“So far, most of the efforts in research on proteins for 3D food printing have been on hydrophilic proteins, and there has been a need for new hydrophobic proteins that are ideally from cost-effective and sustainable protein sources for 3D printing,” Ubeyitogullari said.

In recently published work, Ubeyitogullari and Sorour Barekat, a postdoctoral fellow in the food science department, showed that optimal 3D printing results using grain sorghum protein were achieved with 25% protein and a printing speed of 20 millimeters per second with a 0.64-millimeter nozzle. Increasing the protein concentration to 35% did not improve the 3D printability.

The findings are published in the International Journal of Biological Macromolecules.

“What we’ve shown is that sorghum protein can be made into a novel 3D printable gel, which hasn’t been done before,” Ubeyitogullari said. “Due to their unique structure, these gels can be used in the food and pharmaceutical industries as a bioink to encapsulate medicine or as a carrier of hydrophobic compounds and nutrients.”

Barekat was the lead author of the study titled “Maximizing sorghum proteins printability: Optimizing gel formulation and 3D-printing parameters to develop a novel bioink.” Ubeyitogullari, a faculty member with the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture, served as Barekat’s adviser. Ubeyitogullari is also part of the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas.

More information: Sorour Barekat et al, Maximizing sorghum proteins printability: Optimizing gel formulation and 3D-printing parameters to develop a novel bioink, International Journal of Biological Macromolecules (2025). DOI: 10.1016/j.ijbiomac.2025.140245