Food Engineering

USDA spinning wheat into packaging gold

March 22, 2003
Researchers at the U.S. Depart-ment of Agriculture (USDA) say they have used wheat to make "clamshell" sandwich containers that are more environmentally friendly than old polystyrene clamshells and that keep food warmer than the cardboard containers currently used by many fast-food restaurants.

The researchers presented their findings in April at the 221st national meeting of the American Chemical Society in San Diego. Geoffery Nobes of USDA's Agricultural Research Service in Albany, Calif., reported that he and other researchers are testing biodegradable clam shells made of fiber from the wheat stalk and starch from the wheat kernels. He explained that resulting products are starch-based foam composites with mechanical and thermal properties comparable to those of polystyrene, which have been largely removed from circulation due to environmental concerns. (The product is not biodegradable and contains ozone-damaging chlorofluorocarbons (CFCs).)

Nobes noted that the starch-based containers are biodegradable. He also acknowledged that biodegradable food containers made of potato starch are already in use the U.S., but said that wheat starch and wheat straw are less expensive.

He likened the manufacture of the containers to making waffles, explaining that the starch is extracted from kernels and mixed into water with ground straw. The resulting batter is then poured into a mold and baked. With the resulting product, the fiber serves as the insulating filler and the starch as glue to hold the fiber together.

Assuming further testing is successful, the wheat clamshells could hit the market in two or three years.