In a big step forward, lab-grown meat gets a key ingredient: 3D Fat.

DAILY SCIENCE

In a big step forward, lab-grown meat gets a key ingredient: 3D Fat.

To date, research has focused on producing muscle fibers. This new discovery moves us closer to cultured meat that is actually a delicious and viable alternative to animal slaughter.
April 21, 2023

Researchers have produced lab-grown fat with the texture and potential flavors of the real thing—and crucially, in a way that could be quickly scaled up for the cultured meat industry.

This marks a significant step forward in the production of lab-cultured meat alternatives. So far, relevant research has mainly focused on the production of muscle fibers. But without the fat component, meat products have half the flavor, and a completely different mouth feel. A lack of lab-grown fat is also why most cultured meat products in development have amorphous processed form, such as a patty or a chicken nugget, rather than a cut of steak: without fat, it’s been difficult to mimic the complex structure of meat in its natural state. 

But the researchers on the new eLife study have innovated a way around this.

To start with, they isolated fat cells from mice (as a control) and pigs, and cultured them in a growing medium within a petri dish. This is the usual method of artificially making fat cells. But, it has limitations. With this approach cells can only be grown in extremely thin, 2-dimensional layers that aren’t useful for the production of real meat analogs like a chunky steak. 

And yet, growing fat cells any thicker means that the oxygen and nutrients contained in the growth medium can’t diffuse right through to nourish them all, leaving many to die off. (In bodies, this problem is solved by vast networks of capillaries that reach out and intertwine with the fat matrix to nourish each cell.)

 

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To get around this, the researchers needed to build 3D structures out of their cell cultures. So, once their thin layers of fat cells were fully grown, they took a tiny spatula and scraped them up into dense balls. Yet this claggy mass of fat wasn’t quite good enough: it did’t have the qualities to generate the right texture. To try and achieve that, the researchers took the harvested fat cells and mixed them together with an edible binding agent that would give some buoyancy to the fat. They tried out two varieties: one called microbial transglutaminase, a type of bacterial enzyme; and another called sodium alginate that is derived from seaweed. 

They combined these ingredients in a mold to give the fat a realistic density, and then applied pressure to the samples to test their resistance. This was a useful gauge of how well the cultured fat would hold up between a set of grinding teeth, and also what its mouthfeel would be. 

The test revealed that the sodium alginate-infused fat samples especially were more resilient to pressure, and in fact had a similar bounciness and texture to regular animal fat. This was a promising start.

But to be truly convincing, cultured fat must also contain a diversity of fatty acids, because when cooked, this variety is what creates the uniquely rich flavors and aromas of regular meat. A molecular profile of the samples revealed that the cultured pork fat in particular was a relatively close match for the fatty acids in real pork fat. The researchers also speculate that including a greater range of fatty acids in the growth medium during the culturing stage could bring this profile closer to the real thing—generating artificial fat that’s more flavorful.

The highly-controlled nature of the fat culturing could allow researchers to change the recipe and tweak texture and taste in the future. But for now the major boon is that because of the relatively simplicity of this production method, it can make cultured fat cheaply, and in bulk. With the addition of industrial bioreactors, it becomes highly scalable, the researchers say. 

While it’s still years away, this all moves us closer to the reality of cultured meat that might be a delicious and viable alternative to the real thing. “Taken  together,  these  approaches  offer  a  potential  path  to  producing  meat  (or  realistic  meat  alternatives)  without  animal  slaughter,  while  potentially  being  more  sustainable  than  conventional  meat production,” the researchers write.

Kit Yeung et. al. “Aggregating in vitro-grown adipocytes to produce macroscale cell-cultured fat tissue with tunable lipid compositions for food applications.” eLife. 2023. 

Image: Adobe Stock

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