Download A-Maize-ing Corn, Tortillas

A-Maize-ing Corn & Tortilla Making
Activity:
Students examine corn plant and corn cob, learn about corn, then make tortillas
Goal:
To learn about the structure of the corn plant and how early Americans bred
modern corn from its wild ancestor, teosinte. To understand how corn is used in more foods than just corn-onthe-cob.
Supplies:
Corn plants in the garden, ears of corn, examples of other hinds of grasses (corn is a giant grass).
Masa, measuring cup, water, mixing bowl & spoon, tortilla press, griddle, spatula, salt, napkins.
How to proceed:
Before getting students:
Familimize yourself with the background information on corn provided below.
Set out cooking cart in a location neart electricle outlet. (Suggestion: use outlet next to Gene’s closet, across
from garden shed.) Get a pitcher of water (used for tortillas) – warm if possible.
With students…
Part 1:
Show students corn plants in the edible garden and the corn cob. (All the kernels on the corn plants have been
eaten off, we suspect ground squirrels.)
Discuss the parts of the corn plant. (Use corn diagram provided.)
Explain the history of corn.
Part 2:
Make tortialls.
Tortillas are made from masa. Masa is made by adding an alkaline solution, cooking the corn, grinding the corn,
then (optionally) drying it. (http://en.wikipedia.org/wiki/Masa)
Dried masa can be used as food preservation. (Ask kids why people need to preserve food.)
Discuss how corn is used in many processed foods (see “Zillion Uses for Corn” printout,
http://www.ontariocorn.org/classroom/products.html)
Fun facts
 “Baby corn” (used in asian cooking) is actually corn.
 Corn always has an even number of rows on an ear (usually around 16 rows)
Making Tortillas
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Heat griddle to high
Combine (this should be enough for entire class):
o 3 cups masa
o 2 ⅔ cups warm water
Blend. Add more water if needed.
Form dough into a large ball – divide into 2 balls for two
halves of the class.
Split into individual balls, each ~1 inch in diameter. (Note:
these tortillas will be smaller than store/restraunt tortillas.)
Give one dough ball to each student. Have children roll the
balls, then slightly flatten.
Pressing tortilla dough:
o To avoid having tortillas stick to the press, open a
ziplock bag by cutting open sides, spray a bit of oil
onto inside of ziplock, then put flattened balls into
bag.
o Press in tortilla press.
o Don’t over-flatten. Kids will want to press it as flat
as they can, but when they’re too thin they’ll
crumble when you try to get them off the ziplock.
Transfer to ungreased griddle.
Cooking:
o Try to fit 6 tortillas on griddle so you can have 2
cooking sessions for 10-12 students.
o Have each child in charge of keeping track of their
own tortilla as you cook it.
o Cook ~30 seconds (until lightly browned and edges
begin to dry), turn for ~1 minute (tortilla may puff
slightly), turn again for ~30-45 seconds.
Place on napkin and salt if desired.
Background
Corn is a giant grass
Corn or maize (Zea mays), like all of our cereal grains such as wheat, rics, oats, etc., is in
the grass family (Poaceae). Grasses are members of the monocot class of flowering plants. Monocots have seeds
with one cotyledon or seed leaf, flower parts in multiples of
threes and leaves that have parallel veins. Besides grasses, other examples of monocots
are irises, lilies and orchids.
Corn, like other grasses, is pollinated by the wind. Corn has separate male and female
flowers. Male flowers form pollen and female flowers contain the ovary with the ovules
that will form the seeds. The male flowers of corn are at the top of the plant and form the
tassel. The fernale flowers of corn are along the bases of the leaves as they attach to the
main stalk. The female flower will form the familiar ear of corn with ths seeds (corn
kernels) when pollen travels down the corn silk to fertilize the ovules.
The teosinte story
The genetic origin of corn is an area of active scientific research. The beginning of
modern corn occured about 7,000 years ago when Native Americans residing in southern
Mexico started breeding and raising a wild grass called tosinte that is still found in areas
of Mexico and Central America. Teosinte comes from the Aztec word "teocentli,"
meaning “God’s ear of corn,” and in prts of Mexico, the teosinte plant is called “madre
de maiz" or the mother of maize.
The teocinta plant doesn't produce ears of corn, and instead has a small but edible
“spike” of seeds in a row. These early people probably found that some teosinte plants
produced bigger sprkes and saved seeds from these plants to grow for next year. As they
continued to do this from year to year, they eventually selected for plants that formed
small ears of corn. Such small ears of corn have been found in archaeological digs.
Teosinte and corn are very different in shape, but are genetically very similar. They are
no different from each other than different varieties of corn, and teosinte and modern
corn can interbreed.
We have continued to breed the corn plant to produce the giant ears of corn that are
stacked on our grocery shelves. The modem corn plant is the most efficient cereal crop
to convert solar energy, soil nutrients, carbon dioxide and water into foodstuff. It is also
something of a biological freak as it cannot survive without human intervention. The
kernels of corn, if left to sprout naturally from the cob, are so closely spaced that the
seedlings would not be able to grow normally and reproduce. Thus, modern corn needs
humans to take apart the kernels and plant them.
References
Beadle, G. W. 1980. The ancestry ofcorn. Sci. Am. 2A{l: ll}-llg.
White, S. andDoebley, J. 1998. Of genes and ganomes andthe origin of maize. Trends
in Genetics 14(8): 327-332.