Cereal is any member of the grass family (Gramineae) which produced edible grains usable as food by humans and livestock. Common cereals are rice, wheat, barley, oats, maize (corn), sorghum, rye, and certain millets, with corn, rice, and wheat being the most important.
For the majority of the world’s human population, cereal based foods constitute the most important source of energy and other nutrients. In the poorest parts of the world starchy foods, including cereals, may supply 70% of total energy.
Cereal grains supply most of their food energy as starch. All cereal grains have a fairly similar structure and nutritive value, although the shape and size of the seed may be different.
They are also a significant source of protein, though the amino acid balance is not optimal. Whole grains are good sources of dietary fiber, essential fatty acids, and other important nutrients.
The chemical components of cereal are not evenly distributed in the grain. Bran which represents 7% of the grain contains the majority of the grain fiber, essentially cellulose and pentosans. It is a source of B vitamins and phytochemical and 40-70% of the minerals are concentrated in their outer layer. The endosperm, the main part of the grain (80-85%), contains mostly starch.
Cereals are the main source of energy providing about 350 kcal per 100 grams. Cereal proteins are typically poor in nutritive quality, being deficient in essential amino acid lysine. The proteins of maize are particularly poor, being deficient in lysine and tryptophan (a precursor of niacin).
Three this slices of cereal bread contribute as much protein as an egg. There are two factors of prime importance in relation to protein: the total protein content and the contribution that essential amino acids make to the total.
Therefore rice only partly compensate for its low protein content by a slightly higher lysine value, and for this reason, rice protein is considered to be of better quality.
Rice is a good source of B group vitamins, especially thiamine. It is devoid of vitamins A, D, C and is a poor source of calcium and iron.
The improvement of the nutritional and functional value of cereal storage proteins can be achieved either by regulating the expression of existing genes, or by modifying these gens to improve the value of their corresponding gene products.
The nutritive value of cereal
