Bruin biophysicist’s research pushes forward development of cultured meat
CNSI member Amy Rowat advances technology toward tasty new alternative protein offerings
Peer-Reviewed PublicationIMAGE: IN DEVELOPMENT—A CULTURED MEAT “MINI-BURGER” view more
CREDIT: IMAGE COURTESY: JEANNIE BARBER-CHOI/UCLA
After earning her undergraduate degree, Amy Rowat found herself at a fork in the road. Should she follow her love of science to graduate school for physics, or her passion for cooking to culinary school?
At the time, academia won out. But over the long term, she’s answered the “science or food” question her own way: Why not both?
Now an associate professor of integrative biology and physiology and the holder of UCLA’s Marcie H. Rothman Presidential Chair in Food Studies, Rowat has spiced up both her pedagogy and her research with her gastronomic interests. She is founding director of Science and Food, a campus-based organization that promotes knowledge of science through food and food through science. And in recent years, her research in mechanical biology — exploring how physical forces affect cells — has included studies into cultured meat that may help to eventually add labmade steaks to the grocer’s shelves.
She views that scientific endeavor, aided by the tailwind of private philanthropy, federal research grants and her membership in the California NanoSystems Institute at UCLA, as an aspect of a broader research mission.
“Very broadly, our work is driven by the desire to advance both human and planetary health,” Rowat said. “When I realized there was a gap in the field of alternative proteins, my skillset and the expertise of my lab in biophysics, engineering, cell biology and mechanical biology seemed like a strong fit.”
She points to one of many deleterious effects of the COVID-19 pandemic, disruptions to the supply chain sometimes rendering household staples hard to find, as an example of why expanding the menu of protein-rich foods would benefit society.
“Having other methods to produce animal protein can help increase the resilience of our food system,” she said.
Although there are a number of problems to be solved along the way, cultured meat has the potential to cause less greenhouse gas emission, reduce antibiotic use and occupy less land pound-for-pound than traditional meat from livestock.
“I see cultured meat as a complement to other solutions, such as regenerative agriculture,” Rowat said. “An important aspect is simply to have these alternative protein sources out there.”
Cultured chicken nuggets are already obtainable in Singapore. With similar products working their way through U.S. regulatory processes, Rowat predicts that cultured meat may be available for sale stateside in the next year and a half. Of course, it remains to be seen whether it will find widespread adoption, as plant-based meat alternatives have, or occupy a niche such as feeding people living in extreme environments.
The ability to grow cells in labs is nothing new. However, the cost and the challenges involved with production for consumption at consumer scale have been substantial obstacles. In her research, Rowat is looking for methods that add efficiency to the processes behind cultured meat.
A study she led appearing in the August 2022 edition of the journal Biomaterials signals a step forward for the effort.
Rowat and her colleagues take on a fundamental limitation, that animal cells require some sort of scaffold to grow on if they’re going to develop and function properly. But the petri dish won’t do the trick at industrial scale. Rather, the instrument for the job is a large vat called a bioreactor. To date, cultured meat has been grown on tiny beads, called microcarriers, made of inedible polymers. They must later be separated from the cells, increasing cost and cutting into efficiency.
In the paper, the UCLA team presents a process for making edible microcarriers from gelatin and a food-grade enzyme. Because muscle stem cells have been shown to grow more readily on grooved surfaces — similar to the texture of skeletal muscle — the researchers also describe a technique for patterning their microcarriers. In a proof-of-concept experiment, they cultured cow muscle cells, harvested them into a patty and cooked it with olive oil until browned.
Two resources connected to the CNSI played important roles in the study.
The team made their grooved microcarriers at the UCLA NanoLab, a cleanroom facility for the fabrication of devices that reach down into the scale of billionths of a meter. To measure the mechanical properties of the microcarriers, and confirm the 3D shapes of the grooved ones, the scientists used instruments at the Nano and Pico Characterization Laboratory, a CNSI Technology Center.
The study also benefited from private support, through the Good Food Institute as well as the Noble Family Innovation Fund, a CNSI resource that backs research with potential to launch knowledge-driven commercial enterprises and benefit society.
That philanthropic assistance has borne fruit in more ways than one. Seed funding led to progress that helped attract major grants from the National Science Foundation and the Agriculture and Food Research Initiative of the U.S. Department of Agriculture’s National Institute of Food and Agriculture. And the Noble Fund award is backing experiments at another CNSI Technology Center, the Molecular Screening Shared Resource, which allows scientists to quickly test large libraries of molecules.
Rowat has previously worked with the MSSR on investigations toward fighting cancer; for her cultured meat investigations, the facility will enable her to screen a collection of food ingredients for the ability to aid in growing fat cells. This is the key to another ambition of Rowat’s: to create the capacity for a sumptuous cut of cultured steak shot through with flecks of fat.
“The holy grail in this work is to develop a piece of meat that is more spatially patterned, like a filet mignon, and marbled with fat,” she said. “Fat is really important for mouthfeel, for texture, for flavor and for nutrition.
“That’s the next frontier we’re working on now, and we’re grateful for the Noble Family Innovation Fund support. We’re excited for the next level of findings, which we think will make cultured meat more delicious and healthful.”
JOURNAL
Biomaterials
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Emulsion-templated microparticles with tunable stiffness and topology: Applications as edible microcarriers for cultured meat
UCLA scientists bring cultured meat closer to your kitchen table
The research team led by Amy Rowat is working to overcome several challenges to mass produce cultured meat
Peer-Reviewed PublicationResearchers at UCLA have created an edible particle that helps make lab-grown meat, known as cultured meat, with more natural muscle-like texture using a process that could be scaled up for mass production.
Led by Amy Rowat, who holds UCLA’s Marcie H. Rothman Presidential Chair of Food Studies, the researchers have invented edible particles called microcarriers with customized structures and textures that help precursor muscle cells grow quickly and form muscle-like tissues. Edible microcarriers could reduce the expense, time, and waste required to produce cultured meat with a texture that appeals to consumers. The results are published in the journal Biomaterials.
“Animal cells that can be coaxed to form tissues similar to meats could offer a protein source to a world facing food insecurity caused by threats ranging from epidemics to natural disasters,” said Rowat, who is an associate professor of integrative biology and physiology at the UCLA College. “Cultured meat products are not yet on the market in the US and strategies to enable mass production are still emerging.”
Mass production of cultured meat will involve surmounting several challenges. Current methods can produce a cultured steak that mimics the structure of T-bone, but not at the volume needed for food production. In an animal’s body, the muscle cells most commonly eaten as food grow on a structure called the extracellular matrix, which determines the shape of the mature tissue. Animal tissue can be grown in a lab using scaffolds made from collagen, soy protein or another material to replace the extracellular matrix. This process, necessary to produce whole tissues resembling steaks or chops, is labor intensive and takes weeks, making it hard to scale up for industrial production. It takes about 100 billion muscle cells to produce a single kilogram, or 2.2 pounds, of cultured meat.
Growing larger volumes of cultured meat at a faster pace involves making a paste or slurry of cells in a container called a bioreactor. Unfortunately, without a stiff substrate, meat grown this way lacks the muscle-like structure and therefore, texture and consistency, of what people are used to eating.
Current types of microcarriers can be used to provide a scaffold for cells to attach to, and to organize suspension-grown tissues, but they’re inedible and must be removed from the meat before consumption.
UCLA’s microcarriers can be eaten along with the cultured meat they help grow. The structure and texture of microcarriers could be tuned to speed up the growth of muscle tissue and to optimize meat texture, Rowat said. The edible microcarriers also supported growth of bovine muscle cells and yielded beef that browned nicely when cooked.
Rowat and her UCLA lab of students and postdoctoral scholars Sam Norris, Stephanie Kawecki, Ashton Davis and Kathleen Chen, adapted established water-in-oil emulsion techniques to produce edible particles. They used food ingredients including gelatin and transglutaminase, an enzyme that occurs naturally in meat and mass-produced by bacteria for use as a binding agent in many food products. This helped them create microcarriers of varying stiffness and stabilize the gelatin. To customize the microcarrier surface texture for cell attachment and growth, they devised a way to emboss grooves onto the particles.
The group seeded the microcarriers with mouse precursor muscle cells for an initial test run. They compared the embossed microcarriers to ones with a smooth surface. As a control, they seeded conventional inedible microcarriers with the same type of cells in a separate flask of growth medium. After eight days the cells had formed small clumps. There was no significant difference in the size of clumps on embossed and smooth microcarriers, although cells on the embossed carriers had an initially faster growth spurt.
“We were excited to see a trend toward quicker growth of muscle cells cultured on the grooved microcarriers,” said Kawecki, the study’s co-author who is one of Rowat’s doctoral students. “Any time reduction of cell culture time can significantly reduce the cost of cultured meat production, especially when these processes are brought to scale.”
The internal structure of the tissue grown on edible microcarriers looked more like natural muscle tissue than that grown on inedible carriers, suggesting that the edible microcarriers encouraged more natural growth. Norris, who is a postdoctoral scholar, was surprised to find that cells and microcarriers spontaneously combined to form microtissues that contained a significant amount of myotubes, which are precursors to muscle fibers.
Next, they seeded fresh edible microcarriers with bovine cells and achieved similar results.
“The fact that we can grow large amounts of protein-rich muscle tissue in a stirred bioreactor is a major step in upscaling the production of true cultured meat,” Norris said.
To harvest the tissues, a centrifuge separated the cell clumps from the growth medium. They were rinsed to remove traces of growth medium, compressed into a disc two centimeters, or about 3/4 inch, in diameter, and cooked in a frying pan with olive oil. The cooked patty had the rough, brown surface texture and overall appearance of a tiny hamburger patty.
The researchers said that the microcarrier manufacturing process could be used to produce large amounts of meat quickly and cheaply. Meat of different textures could be produced by manipulating microcarrier stiffness and texture.
The edible microcarriers don’t have to be made with gelatin. Plant-based gels, such as agar-agar or animal-free gelatin, could be used, Rowat said.
The study was supported by the United States Department of Agriculture National Institute of Food and Agriculture; the Good Food Institute; the New Harvest Foundation; the National Science Foundation Innovations at the Nexus of Food, Energy, and Water Systems; a National Science Foundation Boosting Research Ideas for Transformative and Equitable Advances in Engineering Fellow Award; and the UCLA California NanoSystems Institute and the Noble Family Innovation Fund.
JOURNAL
Biomaterials
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