Washing Clothes With…Corn!?
If science has any say in the matter, we might one day be washing our clothes or dishes with corn.
Corn? Well, sort of.
In Peoria, Illinois, Agricultural Research Service (ARS) scientist Randy Shogren has created a new product from corn that could make dishwashing and laundry detergents safer for the environment.
He calls the product a "cobuilder," and he made it from cornstarch. Cornstarch is a smooth, silky powder made from corn that has many uses. One is to thicken gravies and sauces. Another use is in sprays that help iron out wrinkled clothing. A third use turns cornstarch into sugars for making ethanol, a fuel that's less polluting than gasoline.
Cobuilders are added to detergents to prevent "scale." In dishwashers, scale appears as cloudy spots on glasses and dishes. In washing machines, scale can give white clothes a grayish color. Scale also causes the washers to work harder.
Scale happens when a mineral called calcium carbonate crystallizes in "hard" water. This refers to water that has lots of minerals and dissolved salts in it.
One way you call tell whether your home uses hard water is to wet your hands and try to lather up a bar of soap. If the soap doesn't easily bubble up into a froth, then the water is probably hard. But if the soap forms lots of suds, then the water is "soft," meaning it has low amounts of minerals.
Adding cobuilders to detergent prevents scale by keeping calcium carbonate from crystallizing in hard water.
Today's cobuilders are usually made of polyacrylic acid (say, polly-a-KRILL-ic), which comes from petroleum—the same stuff used to make gasoline. But polyacrylic acid doesn't break down in the soil, water, or air.
When polyacrylic acid is used in detergents for washing, "it goes down the drain and into the water supply, where its buildup could be a problem," says Shogren. He's a chemist with ARS's Plant Polymer Research Unit in Peoria.
Cornstarch does break down, or "biodegrade," in the environment, though. There's also plenty of it, and it's cheaper to use than petroleum.
In the laboratory, Shogren used cornstarch to make citric acid and sorbitol. He then combined and heated them to form the cobuilders. Citric acid is a popular food preservative and drink ingredient. Sorbitol gives chewing gums, powdered candies, and other products a sweet, minty taste.
In tests, the starch-based cobuilders stopped scale just as well as petroleum-based cobuilders. The main advantage was that after use, the starch-based ones broke apart into harmless compounds.
Besides helping protect the environment, the biodegradable cobuilders could eventually give corn farmers a new market for their crop. Don't worry! Your clothes wouldn't smell like corn, but they would be clean.
―Jan Suszkiw, Agricultural Research Service, Information Staff.
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