WheatA New Option
Plant physiologist Gregory
Glenn prepares to make
Those lightweight, polystyrene containers that some restaurants give
you for carrying home leftovers or take-out meals are known in the foodservice
industry as "clamshells." Their hinged-lid construction indeed
resembles the architecture nature uses for clams, oysters, and other
Every year, billions of these clamshells and other foodservice containers
made from petroleum-based foams end up in already overstuffed landfills.
Slow to decompose, they become yet another environmental burden.
But the containers, along with other disposable foodservice items such
as plates, bowls, and cups, can also be manufactured with biodegradable
ARS plant physiologist Gregory
M. Glenn is working with EarthShell Corp., the California-based innovators
of potato-starch-based foam products such as burger boxes, to create
environmentally friendly disposables made with starch from wheat, the
world's most widely planted grain. His wheat-starch-based prototypes
are sturdy, attractive, convenient to use, and just as leakproof as
their polystyrene counterparts. Glenn is with the Bioproduct Chemistry
and Engineering Research Unit at ARS's Western Regional Research Center
in Albany, California.
Why use wheat starch in packaging? Because it offers manufacturers
of foodservice products another choice among starches when they're buying
raw materials. That purchasing flexibility can help keep their prices
competitive with the polystyrene products. Another important cost savings:
The machinery already used to make EarthShell's potato-starch-based
containers is suitable for the wheat-starch products as well. That sidesteps
the need for costly retooling at manufacturing plants.
"The machines are presses or molds that work something like giant
waffle irons," explains Glenn. "First, a wheat-starch batter
is poured onto the heated mold, which is then closed and locked. Moisture
in the batter generates steam that, in turn, causes the batter to foam,
expand, and fill the mold. The steam is vented and, when the baking
is finished, the mold is opened, the product is removed, and the cycle
starts again. This whole process takes less than a minute."
A water-resistant coating, added later, helps the container keep its
strength and shape when it's filled with a hot, juicy cheeseburger or
creamy pasta alfredo leftovers, for example. But once the container
hits the backyard compost pile or municipal landfill, it biodegrades
in only a few weeks.
Perhaps having our ready-to-eat meal packed for us in a guilt-free
throwaway container, such as a wheat-starch-based clamshell, will make
eating those foods even more enjoyable.By Marcia
Wood, Agricultural Research Service Information Staff.
This research is part of Quality and Utilization of Agricultural
Products, an ARS National Program (#306) described on the World Wide
Web at www.nps.ars.usda.gov.
Gregory M. Glenn is in the
Chemistry and Engineering Research Unit, Western Regional Research
Center, 800 Buchanan St., Albany, CA 94710; phone (510) 559-5677, fax
"WheatA New Option for Carry-Out Containers" was published in the September 2004 issue of Agricultural Research magazine.