These days, plant-based burgers have it all: they look like meat, they bounce like meat, some of them even ‘bleed’ like real beef. However, there’s one feature that still betrays them: whether it’s made of pea, mushroom or mycoprotein, meat alternatives simply don’t have the succulence of the real thing.
Alternatives really “suffer from this dry, astringent mouthfeel,” explains Anwesha Sarkar, professor of colloids and surfaces at Leeds University.
Now, she and a group of researchers have experimented with some high-tech engineering to change this, successfully transforming plant proteins from their usual dry and cardboard-y texture, into plump lubricating cells that can produce something much closer to the mouthfeel of animal-based foods.
To make this discovery, Sarkar and colleagues needed three main ingredients: plant proteins, water—and an artificial tongue. Writing in Nature Communications, the researchers explain how they isolated proteins from peas and potatoes, then popped them into trays of water where they were hydrated. Then the scientists heated the mixture up, a step that caused the clumped proteins to trap water around their molecules, turning them into something more like a gel. This was the first step to giving them their juicier quality.
However, what the researchers really wanted was a more evenly-spread, diffused network of juicy proteins than the chunky mix they had. So, they used a method called ‘homogenization’, a high-pressure shearing process that broke apart the protein mixture into microscopic particles that formed a more dispersed arrangement, explains Sarkar, who is the corresponding author on the study.
“The proteins that are very aggregated, particle-like and have a gritty, dry texture, we have actually converted into ‘microgels’,” she says. “These are small, microscopic, sponge-like materials of protein networks holding water.”
When this gelled structure was placed under pressure like it would be as food between teeth, it leached water. Next, the researchers used a sophisticated piece of material that mimics the qualities of a human tongue, to scientifically test the mouthfeel this would create.
They found that with their dispersed microgel arrangement, the water-oozing proteins created a level of viscosity—the ‘thickness’ of a liquid—that was equivalent to a 20:80 oil to water emulsion. That’s about the same viscous mouthfeel you’d get from single pouring cream—all accomplished with just water and plants.
For plant alternatives to really take off and relieve the pressure of meat and dairy on the environment, consumers have to feel they’re not sacrificing their enjoyment when they make greener choices.
The new discovery could go a long way to erasing that hurdle, paving the way for plant proteins in a wide array of foods, “for instance converting the plant proteins into microgels for making vegan cheese or plant-based drinks to improve mouthfeel,” says Sarkar.
Perhaps one day, it will even lead to a plant burger that’s indistinguishable from the real thing.
Kew et. al. “Transforming sustainable plant proteins into high performance lubricating microgels.” Nature Communications. 2023.
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