Glenna McCord, age 13, of Brownsville, Texas, for her question:
HOW IS CORN MILLED AND USED?
Corn is the most valuable crop grown in the United States. Although farmers feed about four fifths of the corn grown each year to hogs, cattle, sheep and poultry, the remaining 20 percent is used for food and hundreds of other important corn products we do not eat. Much corn is ground using one of two methods: wet milling or dry milling. Large grinding wheels are used.
If the grain is soaked and treated chemically before grinding, the process is called wet milling. The process of grinding grain while it is dry is called dry milling.
The principal products of wet milling are starch and oil. Cornstarch is important as a food sad as as raw material in many industries. Corn oil is used as food for both people and livestock. The wet miliing industry uses about 150 million bushels of corn each year.
By products of wet milling include zein, a protein used as a source of many plastics, and waxy cornstarch, which is cornstarch made from a special hybrid corn called waxy corn.
Some wet milling processes produce lactic acid, used in the preparation of such foods as cheese, pickles and sauerkraut.
Dry milling separates the corn kernel into its parts: hull, endosperm and germ. Repeated grinding reduces the endosperm to particles of any desired size. The sizes most commonly used include those for hominy grits, cornmeal and corn flour.
Grits, or coarse hominy may be boiled and used as a breakfast cereal, or rolled flat and toasted to make corn flakes. Cornmeal is used 1n bread, griddlecakes and many other foods.
Corn flour has the smallest particles of ground corn. It is used in pancake mixes, as a filler in various meat products and in baking as a substitute for wheat flour.
Byproducts of dry milling include corn oil and livestock feed. Dry corn millers use about 105 million bushels of corn each year.
Wet millers use mostly yellow corn that has a fairly high moisture content.
The water in which wet milled corn is soaked before preparation is called steepwater. It has many uses. It provides a food on which molds and bacteria may grow. Scientists extract penicillin and other antibiotic drugs from the molds and use the bacteria in yeast production. Steepwater also contains inositol, one of the B vitamins.
Some cornmeal is produced by a method called the "old process." This meal is sometimes called "waterground," because many mills use water to provide power.
Millers using the pld process grind whole corn between rotating atones. Leaving the germ in the meal improves the flavor and nutritional values but limits the time that the meal stays fresh.
Most cornmeal sold commercially is made by the "new process." New process meal, made from hulled corn kernels with the germ removed, keeps longer than old process meal. Steel rollers and cylinders and other equipment grind new process meal.