Edible plastics for bales? Corn zein used to make wrapping films


URBANA, Ill. – Livestock producers may soon benefit from using edible and biodegradable plastic-like sheets to cover and protect hay bales in the field from moisture and mold.

Hay coverings are one application of University of Illinois research-produced films made from corn zein, a corn protein that is typically neglected in processing, according to food scientist Graciela Padua.

“The common practice is to wrap hay bales in polyethylene wrapping, which is labor-intensive to use because it must be removed and it often shreds in the process,” Padua said. “It is not healthy for the cows to eat any part of the shredded plastic.”

Padua has created a flexible, biodegradable corn zein film that has plastic qualities and is highly water-resistant.

Previous uses.

Corn zein has been used by the pharmaceutical industry as specialty coatings for various products. Padua is investigating other applications to use the value-added plastics, which are safe for contact with food and animal feed.

“Zein behaves as a plastic in many respects, but is safe for the environment. It is even edible for livestock and wildlife,” Padua said. “It is flexible, water and heat resistant, and is strong enough for the forming process.”

Resin pellets.

Padua has been successful in developing a process to extrude zein resins into resin pellets. The pellets could be sold from the corn millers directly to plastics manufacturers, and used in the same way that plastic pellets are processed.

“The material will look and behave the same as synthetic pellets, so manufacturers would not have to change the product development process,” Padua said. “Our goal was to develop off-the-shelf technology that could be used quickly and easily.”

Other applications.

The research innovations could be used for biodegradable agricultural mulching films and packaging of fresh foods.

Another application might be fast-food wrappers and trays that could be composted rather than sent to the landfills, thus saving space and providing fertilizer, Padua said.

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