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.
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 (see below) are good sources of dietary fiber, essential fatty acids, and other important nutrients.
Most other cereals are ground into flour or meal, which is milled. The outer layers of bran and germ are removed (see seed). This lessens the nutritional value but makes the grain more resistant to degradation and makes the grain more appealing to many palates.
The chemicals 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 this outer layer.
Health-conscious people tend to prefer whole grains, which are not milled. Overconsumption of milled cereals is sometimes blamed for obesity. Milled grains do keep better because the outer layers of the grains are rich in rancidity-prone fats. The waste from milling is sometimes mixed into a prepared animal feed.
Cereals are the main source of energy providing about 350 kcal per 100 grams.
More than 70% of proteins consumed in the world are plant proteins and 71% of them are cereal proteins.
Although cereals make an important contribution to the diet they cannot alone support life because they are lacking in vitamins A (except for yellow maize), B12 and C. Whole cereals also contain phytic acid which may interfere with the absorption of iron, calcium and some trace elements.
Rice proteins are richer in lysine than other common cereal proteins 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.
Generally cereal grains are subjected to different processes to prepare them for human consumption. These processes significantly affect their chemical composition and consequently their nutritional value.
The improvement of the nutritional value of cereal storage proteins can be achieved either by regulating the expression of existing genes, or by modifying these to improve the value of their corresponding gene products.
Nutritional Value of Cereal
