Definição e significado de Cereal

  Oats, barley, and some food products made from cereal grains

Cereals are grasses (members of the monocot family Poaceae, also known as Gramineae)^[1] cultivated for the edible components of their grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grains are grown in greater quantities and provide more food energy worldwide than any other type of crop^{[citation needed]}; they are therefore staple crops.

In their natural form (as in whole grain), they are a rich source of vitamins, minerals, carbohydrates, fats, oils, and protein. However, when refined by the removal of the bran and germ, the remaining endosperm is mostly carbohydrate and lacks the majority of the other nutrients. In some developing nations, grain in the form of rice, wheat, millet, or maize constitutes a majority of daily sustenance. In developed nations, cereal consumption is moderate and varied but still substantial.

The word cereal derives from Ceres, the name of the Roman goddess of harvest and agriculture.

  History

The first cereal grains were domesticated about 12,000 years ago by ancient farming communities in the Fertile Crescent region. Emmer wheat, einkorn wheat, and barley were three of the so-called Neolithic founder crops in the development of agriculture.

  Production

The following table shows annual production of cereals, in 1961,^[2] 2008, 2009, and 2010 ranked by 2010 production.^[3] All but buckwheat and quinoa are true grasses (these two are pseudocereals).

Maize, wheat and rice together accounted for 87% of all grain production worldwide, and 43% of all food calories in 2003,^[3] while the production of oats and rye have drastically fallen from their 1960s levels. Other grains that are important in some places, but that have little production globally (and are not included in FAO statistics), include:

• Teff, popular in Ethiopia but scarcely known elsewhere. This ancient grain is a staple in Ethiopia. It is high in fiber and protein. Its flour is often used to make injera. It can also be eaten as a warm breakfast cereal similar to farina with a chocolate or nutty flavor. Its flour and whole grain products can usually be found in natural foods stores.
• Wild rice, grown in small amounts in North America
• Amaranth, ancient pseudocereal, formerly a staple crop of the Aztec Empire and now widely grown in Africa
• Kañiwa, close relative of quinoa

Several other species of wheat have also been domesticated, some very early in the history of agriculture:

• Spelt, a close relative of common wheat
• Einkorn, a wheat species with a single grain
• Emmer, one of the first crops domesticated in the Fertile Crescent
• Durum, the only tetraploid species of wheat currently cultivated, used to make semolina
• Kamut, an ancient relative of durum with an unknown history

  Farming

  A wheat field in Dorset, England.

While each individual species has its own peculiarities, the cultivation of all cereal crops is similar. Most are annual plants; consequently one planting yields one harvest. Wheat, rye, triticale, oats, barley, and spelt are the "cool-season" cereals.^{[citation needed]} These are hardy plants that grow well in moderate weather and cease to grow in hot weather (approximately 30 °C but this varies by species and variety). The "warm-season" cereals are tender and prefer hot weather. Barley and rye are the hardiest cereals, able to overwinter in the subarctic and Siberia. Many cool-season cereals are grown in the tropics. However, some are only grown in cooler highlands, where it may be possible to grow multiple crops in a year.

For a few decades, however, there has also been increasing interest in perennial grain plants. This interest developed due to advantages in erosion control, reduced need of fertiliser, and potential lowered costs to the farmer. Though research is still in early stages, The Land Institute in Salina, Kansas has been able to create a few cultivars that to produce a fairly good cropyield.^[5]

  Planting

The warm-season cereals are grown in tropical lowlands year-round and in temperate climates during the frost-free season. Rice is commonly grown in flooded fields, though some strains are grown on dry land. Other warm climate cereals, such as sorghum, are adapted to arid conditions.

Cool-season cereals are well-adapted to temperate climates. Most varieties of a particular species are either winter or spring types. Winter varieties are sown in the autumn, germinate and grow vegetatively, then become dormant during winter. They resume growing in the springtime and mature in late spring or early summer. This cultivation system makes optimal use of water and frees the land for another crop early in the growing season.

Winter varieties do not flower until springtime because they require vernalization: exposure to low temperature for a genetically determined length of time. Where winters are too warm for vernalization or exceed the hardiness of the crop (which varies by species and variety), farmers grow spring varieties. Spring cereals are planted in early springtime and mature later that same summer, without vernalization. Spring cereals typically require more irrigation and yield less than winter cereals.

  Threshing; Tacuinum Sanitatis, 14th century.

  Period

Once the cereal plants have grown their seeds, they have completed their life cycle. The plants die and become brown and dry. As soon as the parent plants and their seed kernels are reasonably dry, harvest can begin.

In developed countries, cereal crops are universally machine-harvested, typically using a combine harvester, which cuts, threshes, and winnows the grain during a single pass across the field. In developing countries, a variety of harvesting methods are in use, depending on the cost of labor, from combines to hand tools such as the scythe or cradle.

If a crop is harvested during wet weather, the grain may not dry adequately in the field to prevent spoilage during its storage. In this case, the grain is sent to a dehydrating facility, where artificial heat dries it.

In North America, farmers commonly deliver their newly harvested grain to a grain elevator, a large storage facility that consolidates the crops of many farmers. The farmer may sell the grain at the time of delivery or maintain ownership of a share of grain in the pool for later sale. Storage facilities should be protected from small grain pests, rodents and birds.

  Nutritional facts

Some grains are deficient in the essential amino acid lysine. That is why a multitude of vegetarian cultures, in order to get a balanced diet, combine their diet of grains with legumes. Many legumes, on the other hand, are deficient in the essential amino acid methionine, which grains contain. Thus a combination of legumes with grains forms a well-balanced diet for vegetarians. Common examples of such combinations are dal (lentils) with rice by South Indians and Bengalis, dal with wheat in Pakistan and North India, and beans with corn tortillas, tofu with rice, and peanut butter with wheat bread (as sandwiches) in several other cultures, including Americans.^[6] The amount of crude protein found in grain is measured as Grain Crude Protein Concentration.^[7]

  Standardization

ISO has published a series of standards regarding cereal products and these standards are covered by ICS 67.060.^[8]

  See also

Food portal

  References

  External links

Wikimedia Commons has media related to: Cereals

Look up cereal in Wiktionary, the free dictionary.

• Home Grown Cereals Authority website
• Cereal Recipes
• Cereals by the Vegetarian Society
• Lost Crops of Africa : Grains