Corn oil comes from the whole corn (Zea mays L.), an annual herbaceous plant which is native to Central America. The oil makes up about 5 percent of the whole corn. Corn can be either wet milled to produce corn starch, corn sweeteners, and corn oil, or it can be dry milled to produce grits, flakes, meal, and oil. The crude corn oil that is obtained from the corn germ is supplementary refined by deodorization and removal of free fatty acids. It is yellow in color with a mild but usually individual odor. Refined corn oil is used as a salad and cooking oil or in making margarine. The refined oil has good flavor constancy, and it resists rancidity quite well even though it is highly unsaturated. Almost half of the world's corn oil is produced in the U.S., corn oil ranks above all domestically produced oils except soybean oil. Corn oil has been promoted as a food oil for at least 75 years in the U.S.
A typical fatty acid composition for corn oil is 12 percent palmitic acid, 2 percent stearic acid, 28 percent oleic acid, 57 percent linoleic acid, and 1 percent a-linolenic acid. Typical tocopherol levels in unrefined corn oil average 112 mg/kg a-tocopherol, 50 mg/kg p-tocopherol, 602 mg/kg ү-tocopherol, and 18 mg/kg б-tocopherol for a total of 782 mg/kg.