Sustainable scaffold: Sorghum protein to elevate cultured pork mouthfeel and color

Cultured meat is hailed as a sustainable future meat production technology that requires scaffolds to support cell growth. Researchers at the National University of Singapore (NUS) utilized kafirin — a protein found in red sorghum grain — to develop hybrid cultured pork with “promising potential” in providing higher protein content (22.9%), unique mouthfeel and appearance characteristics.

The anthocyanins in red sorghum also impart a “meat-like” color and antioxidant benefits to the lab-based pork.

“Kafirin is an abundant and non-allergenic protein derived from sorghum. It can also be reclaimed from by-products of the food industry like brewer’s spent grains,” Professor Huang Dejian, deputy head, Department of Food Science and Technology at NUS, tells Food Ingredients First.

“It has excellent film-forming properties and ideal scaffolding materials. Additionally, the natural pigments found in red sorghum can impart a meat-like appearance to the final product, enhancing its visual appeal without the need of using coloring agents or other pigments.”

The team of scientists working on the project also includes Dr. Jing Linzhi, Su Lingshan and Caili Fu from the NUS.

Tapping an “underutilized” source

According to the study, published in the Journal of Agricultural and Food Chemistry, plant proteins are the most promising raw materials for edible scaffolds but remain “underutilized.”

The scientists extracted kafirin from red sorghum grains to create 3D porous scaffolds for growing cultured pork.“Plant-based materials are sustainable, cost effective and can be processed into different shapes and forms. For example, plant-based scaffolds provide necessary support for cell growth and alignment to a certain direction,” underscores Dejian.

“Edible scaffolds can be seamlessly incorporated into the final product to enhance the nutritional value and flavor.”

While wheat gluten, pea protein and soy protein are some of the materials already being used to create scaffolds, the materials are water-soluble and require extra treatment steps or cause problems for those with gluten intolerances or allergies, states the study.

Kafirin protein can address these concerns as a “gluten-free, water-insoluble alternative protein” for scaffolding to grow a prototype cultured pork. 

Formulating hybrid meat

Huang tells us the team extracted kafirin from red sorghum to create 3D porous scaffolds by using sugar cubes as templates.

“Then, we cultured adipose cells from pigs on these scaffolds for 12 days to obtain the hybrid meat, combining both plant-based and cell-based proteins.”

The pork cells readily attached to the kafirin and differentiated into pork muscle and fat cells. 

Porcine skeletal muscle cells (PSCs) and adipose-derived stem cells (ADSCs) could adhere, proliferate and differentiate on protein scaffolds (Image credit: National University of Singapore).

However, Dejian also highlights the team’s challenges while formulating the lab-based pork prototype.

“One of the main challenges was processing kafirin powder into scaffolds with 3D porous structures. To address this, we leveraged the unique solubility of kafirin and developed a template-leaching method using commercial sugar cubes as templates.”

“This approach enabled us to fabricate scaffolds with the desired porosity and structural integrity effectively.”

Color stability

The researchers also found that red pigments from the sorghum provided the cultured meat with a pork-like color and some antioxidant properties. However, the stability of sorghum’s structural proteins led to the cultured meat’s texture and color changing very little after boiling, making the raw and cooked versions look similar.

A prototype cultured pork (left) grown on a scaffold of red sorghum proteins appears similar to real pork (right) (Image credit: Journal of Agricultural and Food Chemistry).“The color stability comes from the anthocyanins in red sorghum, which bond tightly to protein and have high thermal stability.”

“Unlike other added colorants, the natural pigments don’t degrade or bleach upon washing or cooking in water,” explains Dejian.

Enhancing cultivated meat characteristics

The study’s findings demonstrated that sorghum protein can serve as a sustainable scaffold material that can be integrated into the final product and “dramatically” cut down the cost of cultivated meat production.

“Moreover, allergen-free kafirin is particularly attractive as it eliminates a major safety concern for many plant proteins such as gluten. Furthermore, kafirin may enhance the taste and nutritional quality of cultured meat,” Dejian shares.

He adds that the protein also has tremendous potential to be used in formulating plant-based meat analogs. 

“Kafirin possesses unique qualities that make it a valuable addition to the protein options available for alternative meats. Its distinct solubility allows for enhanced stability in solutions.”

However, kafirin lacks essential amino acids like lysine, he notes.

Sorghum proteins can be used to formulate plant-based meat alternatives and gluten-free bread.“Therefore, combining it with other plant proteins such as from soy and pea would offer sustainable plant protein foods with high nutritional value as well as structure and tastes. Wheat gluten is still important in food structures and can not be replaced simply with kafirin.”

Compared to raw lean pork, the team’s cultured pork contains more protein and saturated fat and fewer mono- and polyunsaturated fats, note the scientists.

Besides cultivated meat, sorghum proteins can be used to formulate gluten-free products like bread while providing antioxidant benefits because of their high content of anthocyanins.

Scaling hybrid meat production

The researchers say that additional work is needed to fine-tune the cultured pork’s nutritional and textural properties, but the study “proves kafirin’s utility as a promising scaffold material for cultured meat products.”

“The hybrid pork product, which combines plant proteins and animal proteins, can help reduce the cost of cultured meat. We anticipate that cultured meat manufacturers will incorporate these sorghum protein scaffolds into their cell culture systems to scale up hybrid meat production in the near future,” says Dejian.

The team plans to optimize the kafirin scaffolds for large-scale production and explore adding other functional ingredients to enhance the overall quality and nutritional value of cultured meat.

“In addition, sensory and consumer study of our hybrid meat product is of great importance as well. The long-term plan for us is to commercialize our technology and contribute to sustainable protein solutions that can help combat global warming while promoting human health,” he concludes.