FAYETTEVILLE, Ark. — 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, or ability to repel water, to aid in product cohesion.
Many food materials, especially starches and proteins, are hydrophilic and readily absorb water, which limit 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 percent protein and a printing speed of 20 millimeters per second with a 0.64-millimeter nozzle. Increasing the protein concentration to 35 percent did not improve the 3D printability.
"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," published in International Journal of Biological Macromolecules. 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.
The sorghum protein study was supported by the United Sorghum Checkoff Program. Ubeyitogullari's 3D printed cookies study using sorghum flour was funded by the Arkansas Corn and Grain Sorghum Board.
Optimal sorghum protein ink
Financial support for the sorghum protein 3D food printing study was provided by the United Sorghum Checkoff Program and by the U.S. Department of Agriculture's National Institute of Food and Agriculture AFRI award number: 2023-67022-40164. A rheometer instrument used in the study was also acquired with support from the Arkansas Biosciences Institute.
Barekat and Ubeyitogullari also published a study this May in the Journal of Food Engineering that investigated the incorporation of soy and sorghum proteins as hydrophilic and hydrophobic protein structures for 3D food printing.
3D food printing progress
Ubeyitogullari and a team of researchers in his lab have published several studies in the past two years advancing the foundational knowledge of 3D food printing.
- "Enhancing the stability of lutein by loading into dual-layered starch-ethyl cellulose gels using 3D food printing" was published in May 2023 in Additive Manufacturing.
- "Designing future foods: Harnessing 3D food printing technology to encapsulate bioactive compounds" was published in October 2023 in Critical Reviews in Food Science and Nutrition.
- "Lutein encapsulation into dual-layered starch/zein gels using 3D food printing: Improved storage stability and in vitro bioaccessibility" was published in May 2024 in the International Journal of Biological Macromolecules.
The lead author of these studies was Safoura Ahmadzadeh, formerly a postdoctoral researcher in the food science department with Ubeyitogullari as her adviser. Ahmadzadeh is now an engineer in chocolate processing with Mars, Inc.
To learn more about the Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website
