19 May 2007

A"maize"ing Confusion

Gripe of the Week--It's Not That Type of Corn!


Have you ever noticed that articles in the press about ethanol always feature a picture of an ear of sweet corn? Drives me crazy. Just to clear things up, here are notes to journalists.

There are different types of corn (maize). (Check here or here for a sense of the range of types in this long-domesticated crop.) "Sweet corn" (right, above) is genetically different from other corn: less of its sugar is converted to starch. We harvest it immature and eat it as "corn on the cob", or its shelled kernels as a vegetable.

Yellow dent corn (left, below) is a type where the harder endosperm encloses a starchy center, which shrinks as it dries, giving the characteristic dent in each kernel. This is the kind of corn most widely used in North America as feed and for producing ethanol.
dent corn image from www.heartlandscience.org/agrifood/yelcorn.htm
Other types of corn, especially food-grade yellow and white dent and "flint" corns are used to make food products such as Fritos® and tortillas. "Flint" corn has a hard endosperm suitable for milling into grits or flour. Popcorn is another completely distinct type.

All of these types of corn, and many more for many other uses, were developed by indigenous Americans before the arrival of Europeans. Dent corn is a hybrid of two types developed by native Americans.

Insisting on accurate illustration may seem like a quibble. But it's as if you were writing an article about "oil" and the picture was of petroleum while the article was about cooking oil. Or vice versa. It makes the writer of the article (who may have had no role in selecting the accompanying illustrations) look like an idiot. It causes the reader to lose faith in the whole publication.

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