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; 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.
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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.
The following table shows annual production of cereals, in 1961,[2] 2005, 2006, and 2007 ranked by 2007 production.[3] All but buckwheat and quinoa are true grasses (these two are pseudocereals).
| Grain | Worldwide production (millions (106) of metric tons) |
Notes | |||
|---|---|---|---|---|---|
| 2007 | 2006 | 2005 | 1961 | ||
| Maize | 792 | 695 | 713 | 205 | A staple food of people in America, Africa, and of livestock worldwide; often called corn or Indian corn in North America, Australia, and New Zealand. A large portion of maize crops are grown for purposes other than human consumption. |
| Rice[4] | 659 | 635 | 631 | 285 | The primary cereal of tropical and some temperate regions |
| Wheat | 606 | 605 | 629 | 222 | The primary cereal of temperate regions. It has a worldwide consumption but it is a staple food of North America, Europe, Australia and New Zealand. |
| Barley | 133 | 139 | 141 | 72 | Grown for malting and livestock on land too poor or too cold for wheat |
| Sorghum | 63 | 57 | 59 | 41 | Important staple food in Asia and Africa and popular worldwide for livestock |
| Millet | 34 | 32 | 31 | 26 | A group of similar but distinct cereals that form an important staple food in Asia and Africa. |
| Oats | 25 | 23 | 24 | 50 | Formerly the staple food of Scotland and popular worldwide as a winter breakfast food and livestock feed |
| Rye | 15 | 13 | 15 | 35 | Important in cold climates |
| Triticale | 12 | 11 | 13 | 12 | Hybrid of wheat and rye, grown similarly to rye |
| Fonio | 0.37 | 0.38 | 0.36 | 0.18 | Several varieties of which are grown as food crops in Africa |
| Buckwheat | 2.0 | 2.4 | 2.1 | 2.5 | A pseudocereal, as it is a Polygonacea and not a Poaceae or Gramineae, used in Eurasia. Major uses include various pancake and groats |
| Quinoa | 0.06 | 0.06 | 0.06 | 0.03 | Pseudocereal, grown in the Andes |
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:
Several other species of wheat have also been domesticated, some very early in the history of agriculture:
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. 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, there has also been increasing interest in perennial wheat, rice, ... plants. This, due to advantages in regards to erosion control, reduced need in fertiliser, ... Since then, the Land Institute in Salina, Kansas has been able to create a few cultivars that still manage to produce a fairly good cropyield.[5]
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.
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.
Some grains have a deficit in the essential amino acid lysine. Also some legumes have a deficit in the essential amino acid methionine.
But many grains contain the essential amino acid methionine and many legumes contain the essential amino acid lysine.
That is why a multitude of vegetarian cultures consume a combination of both grains and legumes in an effort to maintain a balanced diet and to receive the benefit of both very essential amino acids.
Also, both grains and legumes contain just as much Protein if not more than many meat and dairy products.
ISO has published a series of standards regarding cereal products and these standards are covered by ICS 67.060.[6]
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