Dairy Byproducts Can Supplement Plastic
May 1, 2007
The average American consumes more than
30 pounds of cheese every year, and each pound produced creates an estimated
nine pounds of the liquid byproducts known as whey.
Disposing of whey isn't difficultin fact, it can be profitable,
thanks, in part, to Agricultural Research Service (ARS) scientists in Wyndmoor, Pa. Researchers
at the ARS Eastern Regional Research Center's (ERRC)
Processing and Products Research Unit have helped create uses for more than
one billion pounds of whey every year in products such as candy, pasta, animal
feeds and even eco-friendly plastics.
Now, food technologist
I. Onwulata is using a process called reactive extrusion to supplement
polyethylenea common nonbiodegradable plasticwith whey proteins.
Reactive extrusion involves forcing plastic material through a heating
chamber, where it melts and combines with a chemical agent that strengthens it
before it's molded into a new shape. Onwulata showed that by combining dairy
proteins with starch during this process, it's possible to create a
biodegradable plastic product that can be mixed with polyethylene and molded
into plastic utensils.
Working with Seiichiro Isobe, a laboratory chief at the
National Food Research Institute, Onwulata created a bioplastic blend. They
combined whey protein isolate, cornstarch, glycerol, cellulose fiber, acetic
acid and the milk protein casein and molded the material into cups. The
dairy-based bioplastics proved to be more pliable than other bioplastics, which
made them easier to mold.
Bioplastic blends can only replace about 20 percent of the polyethylene in a
product, so resulting materials would be only partially biodegradable. However,
Onwulata and his colleagues are currently applying this process to polylactide
(PLA), a biodegradable polymer. This research could someday result in
completely biodegradable bioplastics.
more about the research in the May/June 2007 issue of Agricultural
ARS is the U.S. Department of
Agriculture's chief scientific research agency.