Cereals are staple foods and are important sources of nutrients and rich sources of fiber, vitamins, minerals, and phytochemicals. Wheat, Maize, Millet, Barley, Rice, and corn are the major important grains in the human diet. Cereals are grasses that are grown as food for humans and livestock. Cereal Grasses produce large numbers of types of edibles, dry fruit called a grain. A grain contains a single seed with a large supply of endosperm.