UNIT
9: LESSON 3
STARCH YOUR DAY RIGHT
SUBJECT:
Science
OBJECTIVE:
Students will do a simple experiment that produces raw starch, and will
then learn about commercial separation in a corn refinery.
MEASUREMENT:
Students will understand the refining process for corn, and will appreciate
that nothing is wasted! They will also know where cornstarch comes from.
They'll be ready to learn some of the uses of this starch. (See Unit
9, Lesson 1 and Unit 7, Lesson 4).
BACKGROUND FOR
TEACHERS:
A key component
of the corn kernel is starch. (See Unit 9, Lesson
2)
Cornstarch
- is the food
source for the germinating seed.
- is a source of
many, many food products for people (See Unit
9, Lesson 1).
- is a key ingredient
in the production of ethanol (See Unit
7, Lesson 1).
- is a key ingredient
in the production of biodegradable plastics (See
Unit 7, Lesson 4).
The refining process
described in this lesson is a "wet milling" process. This process soaks
the kernels until the components can be separated mechanically. The
germ is removed for corn oil, and the starch is removed for industrial
or food uses, ethanol, biodegradable plastics, or a variety of other
high value consumer products. The remaining components are mainly used
in animal feed.
A "dry milling"
process is a lower cost option if corn is being processed for ethanol.
In that process, the corn is ground into flour, and the entire product
goes through the fermentation procedure. After the ethanol is distilled
off, the remainder is dried and sold as a 30 percent protein product
called Dried Distillers Grains (DDGs).
STUDENT ACTIVITIES:
1. Ask students
to read the story David Makes Cupcakes, paying
close attention to the last several paragraphs which describe many of
the food products made from corn ("There is cornstarch in the sprinkles.")
2. Conduct the experiment
explained on the following worksheet to demonstrate to students the
separation of starch from the corn kernel. (Worksheet 1)
3. Use the following
handout to explain the three major steps in commercial corn refining:
steeping, germ separation, and starch and gluten separation. This may
make more sense to students if it is used in conjunction with the Kernel
Surgery (Unit 9, Lesson 2) experiment where
students learn the four major parts of a corn kernel.
The handouts state
that the most important refined corn products are corn sweeteners, starch,
oil, ethanol, and feed products. The sweeteners, starch, and oil are
discussed in this unit (Unit 9). Ethanol
is discussed in Unit 7. Animal feed
products are discussed in Unit 6.
These might help the students understand what happens to the corn after
it's refined! (Example 1)
4. Older students
can complete the fill-in-the-blank worksheet and essay questions. (All
can be answered from the above handouts.)
5. If possible,
schedule a field trip to a corn refinery or any corn processing plant
to see actual processing of food products, ethanol, biodegradable plastics,
etc.
