Healthy option: UI's edible film

Healthy option: UI's edible film

Sausage and candy may not top any lists of health foods, but University of Illinois researchers have come up with something that could make them at least a little healthier.

An edible film made of soy protein and oregano might be used for sausage casing and candy coating, among other things.

It also might be used to coat French fries before frying and to replace those foil safety packaging layers that, for example, cover the tops of yogurt containers, said UI Professor Soo-Yeun Lee and graduate student Edel Pruneda-Olguin.

Pruneda-Olguin developed the edible film with Lee, a food science and human nutrition professor, under an exchange program that brings students from Mexico to do research at the UI.

Working with his adviser at the University of Queretaro, Sandra Mendoza, he developed a way of extracting healthful components of oregano, but Pruneda-Olguin was interested in more than the science behind the process.

"I am interested also in the technology part," he said.

His adviser had been thinking of edible films as one possible practical application and that made the UI program and Lee's lab a good fit.

Lee did her doctoral work on developing films from whey protein, a byproduct of cheese production used for low-value animal feed. At the UI, she works on new uses for soy protein.

"Any type of proteins can pretty much make films," she said.

One idea is to reduce the use of synthetic packing materials by developing natural alternatives that tend to be more environmentally friendly because they're either biodegradable or edible.

But the natural materials also may have the potential for health benefits and, in the case of films made of soy protein and oregano, for economic benefits in Illinois and in Mexico.

The benefit for Illinois, one of the world's leading soybean producers, is obvious. And while you may think of oregano as an "Italian" spice, it's actually a significant Mexican crop. Much of the herb sold in the U.S. comes from Mexico.

Besides being tasty, oregano has antioxidant qualities that may have health benefits ranging from warding off heart disease and cancer to slowing age-related degeneration of the brain and eyes. The herb also has antimicrobial qualities that aid in the preservation of foods.

Pruneda-Olguin's technique extracts those qualities in powdered form. That's mixed with extracted, powdered soy protein and the mix is heated and its chemical makeup adjusted to create a film that isn't water soluble, a prerequisite for use in moisture-laden foods.

"You don't want the film to disintegrate," Lee said.

The film is tasteless so it could be used as easily on candy as to hold sausage together.

One drawback at this point is color. The more oregano extract added the darker the film. Not a problem, say, on chocolates but an issue for jelly beans and the like. The researchers may be able to make a clearer film by purifying the oregano extract further.

Lee said the sensory qualities of the film when used as a food coating also need to be tested.

Sausage casing is generally made from collagen, a protein from the connective tissue of animals, like ligaments and tendons.

Meanwhile, many shiny candies, such as chocolate-covered raisins and jelly beans, get their sheen from a type of edible shellac refined from resin secreted by a tiny tropical scale insect in cocoon making. The ingredient has to be imported and refined with an alcohol solvent, making it a hassle to manufacture and an environmental liability, Lee said.

As French fry coating, she said, the film could reduce the amount of oil taken up by the fries in cooking and help keep them fresher and crisper longer because of the preservative qualities of the oregano extract.

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