Corn – October Grain of the Month
Each month we feature a different whole grain on the Whole Grains Council website, including information on its health benefits, cooking tips and recipes, historical/cultural facts, and more. Click here to see the full calendar.
King Corn rules in October, a month that's also been proclaimed as "Poppin' Popcorn Month." Known as "maize" in most of the world, corn is actually the most widely-grown crop in the Americas, where it originated. But is corn a grain or a vegetable? We're often asked that, here at the Whole Grains Council. Fresh corn is usually classified as a vegetable, and dried corn (including popcorn) as a grain.
All About Corn
There is a reason why corn [Zea mays] is the most-produced grain worldwide; it is involved in just about every aspect of our lives. Corn provides about 21 percent of human nutrition across the globe. On top of that, most of the corn grown in the U.S. and Canada is actually fed to animals, so it should be no surprise that corn is America’s number one field crop. There are many other non-culinary uses for the grain as well; it is a key ingredient in ethanol, cosmetics, ink, glue, laundry starch, medicines and fabrics, just to name a few. Native Americans, the original corn farmers, even wove the husks into clothing, baskets and toys. Corn is an essential ingredient in our diets and also in our world.
A Native American name for corn was “mahisi,” which means “that which sustains us.” (In fact, cultivating corn is responsible for turning some Native American tribes from nomadic to settled, agricultural societies). The early settlers transformed the word “mahisi” to “maize.” Later on, the name “corn” came from the generic English term used to denote small particles or particular grains (related to the word "kernel").
There are many different types of corn. The best-known version is Sweet Corn, the traditional summertime treat covered in butter and salt and eaten off the cob. Sweet Corn earned its name from its high sugar content and is generally only consumed by humans. Next is Dent Corn (also known as Field Corn), which is usually fed to livestock and used to make industrial products. The third kind is Flint Corn, which is also known as the decorative Indian Corn that comes in a range of colors and is often symbolic of fall and Thanksgiving. Flint Corn is primarily grown in Central and South America. It is a sub variety of Flint Corn that we use to make popcorn [Zea mays everta].
The origin of corn was something of a mystery for many years, because it does not grow wild anywhere on the planet. Recently though, teamwork by botanists, geneticists and archeologists managed to identify a Mexican grass called teosinte as the wild ancestor of maize. Teosinte is skinny with only a dozen kernels wrapped inside a stone-hard casing, so it at first seemed as though it was more similar to rice rather than corn. But Dr. George W. Beadle, winner of the 1958 Nobel Prize, did studies crossing the two plants and determined that just four or five genes controlled the major differences between maize and teosinte. Botanists used DNA typing, which is exactly the same technology used for paternity tests, to determine where maize came from. The tests showed that all maize was genetically most similar to a teosinte type from the tropical Central Balsas River Valley in Mexico, and the botanists were able to estimate the domestication occurred about 9,000 years ago.
By about 600 A.D., a number of North American Indians were extensively growing corn. Christopher Columbus took it back to Spain with him, and by the 17th century, it was a major crop all over Europe. The Portuguese introduced it to East Africa and Asia and from there it was just a matter of time until it arrived in India and China through established trade routes. Corn is now one of the most widely grown vegetables on Earth, especially in the Americas. It took a considerable length of time but over centuries, farmers were able to transform the small, barely edible teosinte into a delicious, easily harvested food product. As time went by, people bred the corn plants to have bigger ears with more kernels and fewer leaves, making them easier to eat. Without this, we wouldn’t have the corn we know and love today.
Corn and Health
Each whole grain offers different nutrients, and in the case of corn, its high point is Vitamin A – with more than 10 times that of other grains. Recent research shows that corn is also high in antioxidants and carotenoids that are associated with eye health, such as lutein and zeaxanthin. As a gluten-free grain, corn is a key ingredient in many gluten-free foods.
In many traditional cultures, corn is eaten with beans, as they have complementary amino acids that work together to provide complete proteins. In Central and South America, corn is often nixtamalized for better health – soaked in an alkaline solution (often lime-water) – then drained and made into masa flour, tortillas and other foods. The nixtamalization process makes many of the corn kernel's B vitamins hugely more bioavailable, while also adding calcium. (The only downside: a small amount of bran is lost in the soaking, but the US Department of Agriculture accepts masa tortillas as whole grain in its WIC program.) Hominy, a corn product eaten in the southern United States, is also nixtamalized corn.
Click here to see some recent scientific research on corn.
Sweet corn is the best during late summer and early fall (except in Florida, where it is harvested from fall to spring). It should be eaten as soon as possible after harvesting, because the sugars start converting to starches as soon as the corn is picked. However, if you need to store corn, leave the corn in the husk and refrigerate as soon as possible. If the corn has been husked, place it in a plastic bag and store in the refrigerator. Corn that has been cut off the cob can be frozen for 6 months to a year.
Here are some other tips for cooking with fresh sweet corn:
Remove silk when shucking corn by moving a damp paper towel down against the cob, allowing the silk to stick to the towel. This removes small strands of silk that often adhere to the cob after the husks are removed, and does not damage the kernels.
Don't add salt to the water when cooking sweet corn because it will toughen the corn. Add a little sugar to the water to boost the flavor.
Good, fresh, sweet corn does not need to be cooked for long. Try cooking it for just 3 minutes, and see how delicious it can be. You'll never go back to cooking it longer.
Two to three medium ears of corn are equivalent to approximately 1 pound, depending on ear size. Two medium ears equal approximately 1 to 1 1/2 cups of kernels.
Corn is best enjoyed the same day it's picked. Look for farm stands that have picked your corn early that same morning!
Once the all-too-brief sweet corn season is over, you can still enjoy corn in many ways, by cooking with cornmeal, corn flour, and other forms of dried and ground corn. Here are some additional tips for cooking with dried corn products like cornmeal:
Make sure your cornmeal, corn flour, grits, or polenta is labeled "whole corn" or "whole grain corn." If the label says "degermed corn" than the nutritious germ has been removed from the corn, and it's not whole grain.
If you sprinkle cornmeal on both an edgeless cookie sheet and your baking stone, you can easily use a cookie sheet as a pizza peel (thanks to Bob’s Red Mill for this creative suggestion!)
Try some of the recipes below, featuring corn:
Florida, California, Georgia, Washington and New York together accounted for 66 percent of the fresh market sweet corn produced nationally in 2009.
- Corn grows so quickly and thickly that it is especially suited to corn mazes, like the one shown above. Click here to find a corn maze (a maize maze?) near you.
The average ear of corn has 800 kernels, arranged in 16 rows.
There is one piece of silk for each kernel.
A bushel of corn contains about 27,000 kernels.
Each tassel on a corn plant releases as many as 5 million grains of pollen.
Corn is an ingredient in more than 3,000 grocery products.
One bushel of corn can make 33 pounds of sweetener, 32 pounds of starch, or 2 1/2 gallons of ethanol fuel.
Americans consume 52 quarts of popcorn for every man, woman, and child.
- According to a 2006 Whole Grain Awareness survey, only 12 percent of Americans at that time realized that popcorn is a whole grain.
Air-popped popcorn is a low-calorie whole grain snack, with just 31 calories per cup.
- Keep the lid on: popcorn kernels can pop to to three feet in the air!
Photo credits this page (from top): assorted corn – USDA (Keith Weller); Guatemalan woman with corn – USDA (Ronald Riley); nixtamalized corn foods – USDA (Keith Weller); corn maze – USDA.