4th Grade - Social Studies

LESSON PROBLEM: Economics: How does rice from the field get changed into ready to eat rice, rice snacks and cereals?


STUDY GUIDE

Before the product of the rice plant can be eaten there is a process that it must go through. It is called the milling process. After the farmer harvests the rough rice, it goes to a mill, a type of agricultural factory, where machines work on the rice to make it edible.

The first step at the mill is to clean weeds, straw and any other foreign materials from the rice. So, the rough dried rice goes through the cleaning machines.

Some of the rice goes straight to the shelling machines, where the hull is removed. The hull is the outer covering of the rice. We can compare it to the husk of an ear of corn. The color of the hulled rice remains brownish because the bran layers that give it a tan color remain. You may have eaten rice that has been hulled, but not further processed. We call it "brown rice". It is edible rice with the least amount of processing. Brown rice has a chewier texture than white rice. White rice has had the bran layer removed. Brown rice is also used to make breakfast cereals, rice chips and other snacks.

Some of the rice remains unhulled and goes into a warm water soaking process which is under pressure, then steamed and dried. This becomes the "parboiled" rice. Parboiling makes the grain of rice harder. The hull, and in some cases the hull and bran is removed after this process. This type of rice takes a few minutes longer to cook than regular white rice. Some of the parboiled brown rice moves to the sorting machines where it is graded and made ready for packaging. It can be packaged as parboiled brown rice, or it can go to the mill or polishing machine to have the bran removed to become parboiled white rice. It then goes to the sorting machine. At the sorting machine broken pieces of rice kernels and discolored grains are taken off. These products are used for pet foods, rice flour and other products.

Some brown rice is sent to the milling or polishing machine so that the rice bran is completely taken off. The rice bran is used in vitamins, baking mixes and cereal. Once the rice is polished, it is called "white rice," "milled white rice," or "polished rice." This is the most popular kind of rice. White rice is just as healthy for you as brown rice, because it is enriched with the vitamins iron, niacin and thiamine.

Both milled white rice and brown rice can be pre-cooked for instant rice products. Since the brown rice still has its nutritious bran layer, usually no other nutrients are added. The milled rice and instant rice are enriched with vitamins and minerals before packaging, so they are as nutritious as brown rice.

The typical yield from milled products from 100 lbs. of paddy rice is 80 lbs. of brown rice, from which we get 55 lbs. of whole kernel white rice and about 8 lbs. of rice bran. Take a look at this chart from the University of California at Davis, to better understand the breakdown of processed rice.




ACTIVITIES

Using an 8 1/2" by 14" piece of paper, draw a flow chart of the milling process. Place the names of the forms of rice in one color and the processes rice goes through in another color.

For example, draw all rectangles. Write in the top one the words, "Dried Rough Rice". Then draw an arrow pointing down to the next rectangle in another color. Write inside the second rectangle, "Cleaning Machines".

When you need to make a branch of two lines to separate the brown rice from the white or parboiled rice, do that. You will need one at the cleaning machine and at the shelling machine. Where else will you need one?

If you do it your own way, you may not have the same number of types of packaged rice at the end as was mentioned in the story above. However, you can have as many as seven types: packaged parboiled brown rice, packaged regular brown rice, packaged instant brown rice, also packaged milled rice, packaged enriched rice, packaged instant rice and packaged milled parboiled rice. Have fun!




EXTENDED LEARNING

You have learned about the MILLING PROCESS of rice. Rice is an important product produced in America.

Try to draw a cross section of a grain of rice on a 8 1/2 by 11" paper. Start with a large outside shell.

Show three cuts into it, so that the outside hull shows 20%, the rice bran shows 10%, the whole kernel shows 55%, and the remainder shows 15%.

Clearly label your picture. Take it to your parents, classmates and teachers. Ask them to guess what the percentages are by giving the least amount of hints. You may be surprised how little others know about rice. Study for the quiz. Take it when you are ready.




RESOURCES

Rice Ecosystems
http://irri.org/crucial.htm

Rice Glossary
http://agronomy.ucdavis.edu/uccerice/riceglos.htm

Rice Grain and Plant
http://www.tipsofallsorts.com/rice.html

Milling Process
http://www.riceland.com/rice/milling.html



VOCABULARY
  • milling
  • yields
  • hull
  • harvest
  • kernel
  • bran


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Rice Farm Animals:
Rice farms have lots of animals. Click here to learn more about rice farms and the animals that live there.
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