? Rice | ||||||||||||||
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| [image] Mature seedheads of American long grain rice | ||||||||||||||
| Scientific classification | ||||||||||||||
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| Binomial name | ||||||||||||||
| Oryza sativa L. |
Rice (Oryza sativa) is a species of grass in the genus Oryza, native to tropical and subtropical southeastern Asia, where it grows in wetlands. It is an Annual plant, growing to 1-1.8 m tall, occasionally more, with long slender leaves 50-100 cm long and 2-2.5 cm broad. The small wind-pollinated flowers are produced in a branched arching to pendulous Inflorescence 30-50 cm long. The seed is a Grain (caryopsis) 5-12 mm long and 2-3 mm thick.
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Rice is often grown in paddies - shallow puddles carefully controlled to ensure the appropriate water depth (typically 15 cm). Rice paddies sometimes serve a dual agricultural purpose by also producing edible fish or frogs, a useful source of protein. The farmers take advantage of the rice plant's tolerance to water: the water in the paddies prevents weeds from outgrowing the crop. Once the rice has established dominance of the field, the water can be drained in preparation for harvest. Paddies increase productivity, although rice can also be grown on dry land (including on terraced hillsides) with the help of chemical weed controls.
In some instances, a deepwater strain of rice often called floating rice is grown. This can develop elongated stems capable of coping with water depths exceeding 2 meters (6 feet).
Rice paddies are an important habitat for birds such as herons and warblers, and a wide range of amphibians and snakes. They perform a useful function in controlling insect pests.
Whether it is grown in paddies or on dry land, rice requires a great amount of water compared to other food crops. Rice growing is a controversial practice in some areas, particularly in the United States and Australia, where rice farmers use 7% of the nation's water to generate just 0.02% of GDP. However, in nations that have a periodical rain season and typhoons, rice paddies serve to keep the water supply steady and prevent floods from reaching a dangerous level.
Rice blast, caused by the Fungus Magnaporthe grisea is the most significant disease affecting rice cultivation.
Rice bran, called nuka in Japan, is a valuable commodity in Asia and is used for many daily needs. It is a moist inner oily layer that is heated to produce a very healthy oil. Another use is to make a kind of pickled vegetable.
The raw rice may be ground into Flour for many uses as well, including making many kinds of beverages such as Amazake, Horchata, Rice milk, and Sake. Rice flour is generally safe for people on a Gluten-free diet.
The processed rice seeds are usually boiled or steamed to make them edible, after which they may be fried in oil, or Butter, or beaten in a tub to make Mochi.
[image] Rice, like other Cereal grains, can be puffed (or popped). This process takes advantage of the grains' Moisture content and typically involves heating grain pellets in a special chamber. Further puffing is sometimes accomplished by processing pre-puffed pellets in a low-Pressure chamber. By the Ideal gas law, one can see that both lowering the local pressure or raising the moisture Temperature would result in an increase in Volume prior to moisture Evaporation, thus resulting in a puffy Texture.
Rice is cooked by Boiling it in water until it has been heated enough and has absorbed enough water to become soft and fluffy, and in some cases, sticky. This process can be done either using a measured amount of water fixed so that it is exactly enough to cook the rice, or by using excess water which is drained away once the rice is cooked. In Asia, many households expediate the cooking process using an electrical device known as a Rice cooker.
Rice may be soaked prior to cooking. Like beans this will enable the rice to cook faster, and to have an improved Texture due to increased expansion of the rice grains.
When preparing brown rice, a nutritionally superior method of preparation known as GABA Rice may be used. Ths involves soaking washed brown rice for 8 to 12 hours in warm water (38 °C or 100 °F) prior to cooking it. This process stimulates Germination, which activates various enzymes in the rice. By this method, a result of the United Nations Year of Rice, it is possible to obtain a complete Amino acid profile, including GABA.
It is believed that common wild rice, Oryza rufipogon, was the wild ancestor of Asian rice [:Rice}}#endnote_riceorigins]. O. sativa appears to have originated around the Foothills of the Himalaya, with O. sativa var. indica on the Indian side and O. sativa var. japonica on the Chinese side.
African rice has been cultivated for 3500 years. Between 1500 and 800 BCE, O. glaberrima propagated from its original center, the Niger River Delta, and extended to Senegal. However, it never developed far from its original region. Its cultivation even declined in favor of the Asian species, possibly brought to the African Continent by Arabs coming from the east coast between the 7th and 11th centuries.
Dry-land rice was introduced to Japan circa 1000 BCE. Later wet-paddy rice agriculture was brought to Japan by the Yayoi circa 300 BCE.
O. sativa was adapted to farming in the Middle East and Mediterranean Europe around 800 BCE. The Moors brought it to Spain when they conquered the country circa 700 CE. After the middle of the 15th century, rice spread throughout Italy and then France, later propagating to all the continents during the great age of European exploration. In 1694, rice arrived in South Carolina, probably originating from Madagascar. The Spanish brought rice to South America at the beginning of the 18th century.
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In the United States, Colonial South Carolina and Georgia grew and amassed great Wealth from the Slave labour obtained from the Senegambia area of West Africa. At the port of Charleston, through which 40% of all American slave imports passed, slaves from this region of Africa brought the highest prices, in recognition of their prior knowledge of rice culture, which was put to use on the many rice plantations around Georgetown, Charleston, and Savannah. From the slaves, plantation owners learned how to dike the marshes and periodically flood the fields. At first the rice was milled by hand with wooden paddles, then winnowed in sweetgrass baskets (the making of which was another skill brought by the slaves). The invention of the rice mill increased profitability of the crop, and the addition of water power for the mills in 1787 by Millwright Jonathan Lucas was another step forward. Rice culture in the southeastern U.S. became less Profitable with the loss of slave labour after the American Civil War, and it finally died out just after the turn of the 20th century.
World trade figures are very different, as only about 5-6% of rice produced is traded internationally. The largest three exporting countries are Thailand (26% of world exports), Vietnam (15%), and the United States (11%), while the largest three importers are Indonesia (14%), Bangladesh (4%), and Brazil (3%).
Indian rice cultivars include long-grained and aromatic Basmati (grown in the North), long and medium-grained Patna rice and short-grained Masoori. Rice in East India and South India, is usually prepared by boiling the rice in large pans immediately after harvesting and before removing the husk; this is referred to in English as parboiled rice. It is then dried, and the husk removed later. It often displays small red speckles, and has a smoky flavour from the fires. Usually coarser rice is used for this procedure. It helps to retain the natural vitamins and kill any fungi or other contaminants, but leads to a peculiar odour. This rice is easier on the stomach to digest and is mostly used by the blue collar workers. In South India, it is also used to make idlis.
Aromatic rices have definite aromas and flavours; the most noted cultivars are the aforementioned basmati, Patna rice, and a Hybrid cultivar from America sold under the trade name, Texmati. It is a genetically modified patented cultivar that is creating great controversy. Both Basmati and Texmati have a mild Popcorn-like aroma and flavour. In Indonesia there are also red and black cultivars.
High-yield cultivars of rice suitable for cultivation in Africa and other dry ecosystems called the new rice for Africa (NERICA) cultivars have been developed. It is hoped that their cultivation will improve Food security in West Africa.
Scientists are working on so-called Golden rice which is genetically modified to produce beta Carotene, the precursor to vitamin A. This has generated a great deal of controversy over whether the amount of beta carotene would be significant and whether genetically modified foods are desirable.
Draft genomes for the two most common rice cultivars, indica and japonica, were published in April 2002. Rice was chosen as a Model organism for the biology of grasses because of its relatively small genome (~430 megabase pairs). As a result rice was the first plant or animal to have its complete genome mapped [:Rice}}#endnote_ricegenomefullmap]. Basmati rice is the oldest, common progenitor for most types.