IEEE Spectrum June, 2013 - 68

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how do you mak e vegetable proteIn taste lIk e anImal proteIn?
By using an industrial-age technology called extrusion.
You may have had your first experience with extrusion before
you were out of diapers, as a toddler playing with a toy called the
Play-Doh Fun Factory. You pushed Play-Doh through a die to make
Play-Doh strips that had the cross section of a star or a circle. The
basic technique was first used more than 200 years ago to make
lead pipe, and then wire, and still later, spaghetti. Extruders now
produce breakfast cereal, puffed snacks, and pet foods.
The use of vegetables, nuts, and grains to make meatlike foodstuffs goes back to the 19th century, at least. In Asia, some meat
substitutes grew out of Buddhist traditions, which eschew the
consumption of meat, particularly in a temple. But the enterprise
took a quantum leap in the late 1950s and early 1960s, when the
earliest U.S. patents were issued for the use of extrusion to make
"meat analogues" from vegetable proteins. Many companies
were involved, including Archer Daniels Midland, the extrusionmachine maker Wenger, A.E. Staley, Cargill, Miles Laboratories,
and Worthington Foods.
There are dozens of meat replacements on the market in
Europe and a similar number in North America. Different products make use of different kinds of proteins or combinations of
proteins, including wheat gluten and a protein derived from a
fungus. But the majority are based on soy protein, sometimes
in combination with other vegetable proteins, which has been
extruded to give it a fibrous, meatlike texture.
Jeroen Willemsen, a cofounder of the Dutch company Ojah, in
Ochten, which makes the meat alternative Plenti, points to three
generations of meat substitutes. The first was a "tofu generation," based on the bean curd. These products didn't taste much
like meat but had reasonably high levels of protein. The second
generation features ready-to-use items that resemble sausages,
meatballs, hamburger patties, and the like. The key ingredient
is texturized vegetable protein. It is produced by extrusion of a
low-moisture precursor and then dried into flakes or granules.
These are rehydrated and incorporated into the final, ready-to-use
product, which is sold frozen or chilled.
The third generation, which includes Plenti and Beyond Meat,
are a special category known in the food industry as high-moisture
meat analogues, or HMMAs. They are designed to have the taste
and mouthfeel of genuine muscle meats- chunks of chicken
breast, a piece of smoked eel, or shredded pork. The new analogues are meatlike enough to be sold in much the same way
as meat-refrigerated and intended for use in soups, sandwiches,
chilies, burritos, and other dishes where sauces and seasonings
will help enhance the meaty illusion.
Being a relatively recent development, HMMAs occupy just
a thin slice of today's meat-substitute market. Researchers
extruded the first HMMAs in the 1980s, following pioneering
68

jun 2013

north american

SPectrum.ieee.orG

half Baked

Out of the
Test Tube
and Into
the Fryer
how much would you pay
for a guilt-free hamburger?

work at the Protial research and development laboratory in
Angers, France. But a flurry of patents in just the past seven
years confirms that tinkering over the last decade has greatly
improved the appeal of these foods.

here's the challenge, accordIng to ethan brown, the founder
of Beyond Meat: "The difficulty is in matching perfectly the tension between biting cleanly through the product, with just the
right amount of push-back, and the fiber structure."
Fortunately, to meet that challenge you have a marvel of modern industry, the twin-screw thermoplastic food extruder. It precisely applies heat, pressure, and mechanical shear forces to a
foodstuff, typically a floury mix rich in protein, to transform it
illuStration by

Jason lee

http://SPectrum.ieee.orG

Table of Contents for the Digital Edition of IEEE Spectrum June, 2013