Dictionary:

rice

  (rīs)

1. A cereal grass (Oryza sativa) that is cultivated extensively in warm climates for its edible grain.
2. The starchy grain of this plant, used as a staple food throughout the world.

To sieve (food) to the consistency of rice.

[Middle English, from Old French ris, from Old Italian riso, from Latin oryza, from Greek oruza, of Indo-Iranian origin.]

Background

As a main source of nourishment for over half the world's population, rice is by far one of the most important commercial food crops. Its annual yield worldwide is approximately 535 million tons. Fifty countries produce rice, with China and India supporting 50% of total production. Southeast Asian countries separately support an annual production rate of 9-23 million metric tons of which they export very little. Collectively, they are termed the Rice Bowl. Over 300 million acres of Asian land is used for growing rice. Rice production is so important to Asian cultures that oftentimes the word for rice in a particular Asian language also means food itself.

Rice is a member of the grass family (Gramineae). There are more that 10,000 species of grasses distributed among 600 genera. Grasses occur worldwide in a variety of habitats. They are dominant species in such ecosystems as prairies and steppes, and they are an important source of forage for herbivorous animals. Many grass species are also primary agricultural crops for humans. As well as rice, they include maize, wheat, sorghum, barley, oats, and sugar cane.

Typically, grass species are annual plants or are herbaceous perennials that die back to the ground at the end of the growing season and then regenerate the next season by shoots developing from underground root systems. Shoots generally are characterized by swollen nodes or bases. Leaves are long and narrow, varying in width from 0.28-0.79 in (7-20 mm). Flowers are small and are called florets. Grasses pollinate by using the wind to widely and opportunistically disperse grass pollen. The fruits are known as a caryopsis or grain, are one-seeded, and can contain a large concentration of starch.

Classified in the genus Oryza, there are two species of domesticated rice—O. sativa and 0. glaberrima. 0. sativa is the most common and often cultivated plant, occurring in Africa, America, Australia, China, New Guinea, and South Asia. The natural habitat of rice is tropical marshes, but it is now cultivated in a wide range of subtropical and tropical habitats. Unlike other agricultural crop grasses, rice plants thrive under extremely moist conditions and moderate temperatures. The ideal climate is roughly 75° F (24° C). Average plant height varies between 1.3-16.4 ft (0.4-5 m). Its growth cycle is between three to six months (agriculturally, this is broken down into three phases lasting approximately 120 days). Rice plants produce a variety of short- to long-grain rices, as well as aromatic grains.

There are three different types of rice: japonica, javanica, and indica. Japonica rice varieties are high yielding and tend to be resistant to disease. Javanica types of rice fall between japonica and indica varieties in terms of yield, use, and hardiness. Although quite hardy, indica yield less than japonica types and are most often grown in the tropics.

Because cultivation is so widespread, development of four distinct types of ecosystems has occurred. They are commonly referred to as irrigated, rainfed lowland, upland, and flood-prone agroecological zones. Irrigated ecosystems are the primary type found in East Asia. Irrigated ecosystems provide 75% of global rice production. Irrigated rice is grown in bunded (embanked), paddy fields. Rainfed lowland ecosystems only sustain one crop per growing season and fields are flooded as much as 19.7 in (50 cm) during part of the season. Rainfed low-land rice is grown in such areas as East India, Bangladesh, Indonesia, Philippines, and Thailand, and is 25% of total rice area used worldwide. Production is variable because of the lack of technology used in rice production. Rainfed lowland farmers are typically challenged by poor soil quality, drought/flood conditions, and erratic yields. Upland zones are found in Asia, Africa, and Latin America. It is the primary type of rice ecosystem in Latin America and West Africa. Upland rice fields are generally dry, unbunded, and directly seeded. Land utilized in upland rice production runs the gamut of descriptions. It can be low lying, drought-prone, rolling, or steep sloping. Usually, crops are either sown interspersed with another crop, intermittently with another crop, or the crop is shifted every few years to a new location. Lastly, flood-prone ecosystems are prevalent in South and Southeast Asia, and are characterized by periods of extreme flooding and drought. Yields are low and variable. Flooding occurs during the wet season from June to November, and rice varieties are chosen for their level of tolerance to submersion.

Rice is mostly eaten steamed or boiled, but it can also be dried and ground into a flour. Like most grains, rice can be used to make beer and liquors. Rice straw is used to make paper and can also be woven into mats, hats, and other products.

History

Since it has been such an important grain worldwide, the domestication and cultivation of rice is one of the most important events in history that has had the greatest impact on the most people. When and where the domestication of rice took place is not specifically known, but new archaeological evidence points to an area along the Yangtze River in central China and dates back as far as 11,000 years. Researched by a team of Japanese and Chinese archaeologists and presented at the 1996 International Symposium on Agriculture and Civilizations in Nara, Japan, radiocarbon testing of 125 samples of rice grains and husks, as well as of rice impressions in pottery, from sites located along a specific portion of the Yangtze unanimously indicate a median age of over 11,000 years. Another discovery of possibly the oldest settlement found in China, which is located closely upstream from the other sites, gives credence to the new findings.

In any event, it wasn't until the development of puddling and transplanting of the rice plant that the spread of rice as an agricultural crop really began. Practiced in the wetlands of China, the concept of the rice paddy was adopted by Southeast Asia in roughly 2000 B.C. Wetland cultivation techniques migrated to Indonesia around 1500 B.C. and then to Japan by 100 B.C. To the West, rice was also an early important crop in India and Sri Lanka, dating as far back as 2500 B.C. and 1000 B.C. respectively.

The spread to Europe, Africa, and America occurred more slowly, first with the Moor's invasion of Spain in 700 A.D. and then later to the New World during the age of exploration and colonialism. Rice has been grown in the United States since the seventeenth century in such areas as the southeastern and southern states, as well as California.

Raw Materials

The only raw material needed for commercial production of rice is the rice seed or seedlings. Additional use of herbicides, pesticides, and fertilizer can increase the likelihood of a larger yield.

Design

Varieties of rice are selected and grown specifically for their end use. In the United States, long-grain rice is typically used for boiling, quick-cook products, and soup. Whereas, shorter-grain rice is used in cereal, baby food, and beer/liquors.

The Manufacturing
Process

Preparation

• Prior to planting, minimal soil manipulation is needed to prepare for cultivation. If the rice will be grown on a hilly terrain, the area must be leveled into terraces. Paddies are leveled and surrounded by dikes or levees with the aide of earth-moving equipment. Then, the fields are plowed before planting. In the United States, rice is most often planted on river deltas and plowing is accomplished with a disk plow, an off-set disk plow, or a chisel. Adequate irrigation of the terrace or river delta bed is required and accomplished by leveling and by controlling water with pumps, reservoirs, ditches, and streams.

Planting

• Rice seeds are soaked prior to planting.
• Depending on the level of mechanization and the size of the planting, seeding occurs in three ways. In many Asian countries that haven't mechanized their farming practices, seeds are sown by hand. After 30-50 days of growth, the seedlings are transplanted in bunches from nursery beds to flooded paddies. Seeds can also be sown using a machine called a drill that places the seed in the ground. Larger enterprises often found in the United States sow rice seed by airplane. Low-flying planes distribute seed onto already flooded fields. An average distribution is 90-100 lb per acre (101-111 kg per hectare), creating roughly 15-30 seedlings per square foot.

Harvesting

• Once the plants have reached full growth (approximately three months after planting) and the grains begin to ripen—the tops begin to droop and the stem yellows—the water is drained from the fields. As the fields dry, the grains ripen further and harvesting is commenced.
• Depending on the size of the operation and the amount of mechanization, rice is either harvested by hand or machine. By hand, rice stalks are cut by sharp knives or sickles. This practice still occurs in many Asian countries. Rice can also be harvested by a mechanized hand harvester or by a tractor/horse-drawn machine that cuts and stacks the rice stalks. In the United States, most operations use large combines to harvest and thresh—separate the grain from the stalk—the rice stalks.
• If the rice has been harvested by hand or by a semi-automated process, threshing is completed by flailing the stalks by hand or by using a mechanized thresher.

Drying

• Before milling, rice grains must be dried in order to decrease the moisture content to between 18-22%. This is done with artificially heated air or, more often, with the help of naturally occurring sunshine. Rice grains are left on racks in fields to dry out naturally. Once dried, the rice grain, now called rough rice, is ready for processing.

Hulling

• Hulling can be done by hand by rolling or grinding the rough rice between stones. However, more often it is processed at a mill with the help of automated processes. The rough rice is first cleaned by passing through a number of sieves that sift out the debris. Blown air removes top matter.
• Once clean, the rice is hulled by a machine that mimics the action of the handheld stones. The shelling machine loosens the hulls from the rice by rolling them between two sheets of metal coated with abrasives. 80-90% of the kernel hulls are removed during this process.
• From the shelling machine, the grains and hulls are conveyed to a stone reel that aspirates the waste hulls and moves the kernels to a machine that separates the hulled from the unhulled grains. By shaking the kernels, the paddy machine forces the heavier unhulled grains to one side of the machine, while the lighter weight rice falls to the other end. The unhulled grains are then siphoned to another batch of shelling machines to complete the hulling process. Hulled rice grains are known as brown rice.

Milling

Since it retains the outer bran layers of the rice grain, brown rice needs no other processing. However along with added vitamins and minerals, the bran layers also contain oil that makes brown rice spoil faster than milled white rice. That is one of the reasons why brown rice is milled further to create a more visually appealing white rice.

• The brown rice runs through two huller machines that remove the outer bran layers from the grain. With the grains pressed against the inner wall of the huller and a spinning core, the bran layers are rubbed off. The core and inner wall move closer for the second hulling, ensuring removal of all bran layers.
• The now light-colored grain is cooled and polished by a brush machine.
• The smooth white rice is conveyed to a brewer's reel, where over a wire mesh screen broken kernels are sifted out. Oftentimes, the polished white rice is then coated with glucose to increase luster.

Enriching

The milling process that produces white rice also removes much of the vitamins and minerals found primarily in the outer bran layers. Further processing is often done in order to restore the nutrients to the grain. Once complete, the rice is called converted rice.

• White rice is converted in one of two ways. Prior to milling, the rice is steeped under pressure in order to transfer all the vitamins and minerals from the bran layers to the kernel itself. Once done, the rice is steamed, dried, and then milled. Rice that has already been milled can be submersed in a vitamin and mineral bath that coats the grains. Once soaked, they are dried and mixed with unconverted rice.

Quality Control

Quality control practices vary with the size and location of each farm. Large commercial rice farms in the United States more often than not apply the most effective combination of herbicides, fertilization, crop rotation, and newest farming equipment to optimize their yields. Smaller, less mechanized operations are more likely to be influenced by traditional cultural methods of farming rather than high technology. Certainly, there are benefits to both approaches and a union of the two is ideal. Rotating crops during consecutive years is a traditional practice that encourages large yield as is the planting of hardier seed varieties developed with the help of modern hybridization practices.

Byproducts/Waste

Straw from the harvested rice plants is used as bedding for livestock. Oil extracted from discarded rice bran is used in livestock feed. Hulls are used to produce mulch that will eventually be used to recondition the farm soil.

The essential use of irrigation, flooding, and draining techniques in rice farming also produces runoff of pesticides, herbicides, and fertilizers into natural water systems. The extensive use of water in rice farming also increases its level of methane emissions. Rice farming is responsible for 14% of total global methane emissions.

The Future

With one out of every three people on earth dependent on rice as a staple food in their diet and with 80-100 million new people to be fed annually, the importance of rice production to the worldwide human population is crucial. Scientists and farmers face the daunting task of increasing yield while minimizing rice farming's negative environmental effects. Organizations such as the International Rice Research Institute (IRRI) and the West African Rice Development Association (WARDA), and Centro Internacional de Agricultura Tropical (CIAT [International Center for Tropical Agriculture]) are conducting research that will eventually lead to more productive varieties of rice and rice hybrids, use of less water during the growing season, decrease in the use of fresh organic fertilizer that contributes to greenhouse effect, and crops more resistant to disease and pests.

Where To Learn More

Books

Huke, R.E. and E.H. Rice: Then and Now. International Rice Institute, 1990.

Johnson, Sylvia A. Rice. Minneapolis, MN: Lerner Publications Co., 1985.

Periodicals

"Limiting Rice's Role in Global Warming." Science News (July 10, 1993): 30.

Normile, Dennis. "Yangtze Seen as Earliest Rice Site." Science (January 17, 1997): 309.

Other

Riceweb. http://www.riceweb.org/ (June 29, 1999).

[Article by: Jacqueline L. Longe]

The plant Oryza sativa is the major source of food for nearly one-half of the world's population. The most important rice-producing countries are mainland China, India, and Indonesia, but in many smaller countries rice is the leading food crop. In the United States, rice production is largely concentrated in selected areas of Arkansas, California, Louisiana, and Texas. See also Carbohydrate; Cyperales; Wheat.

Over 95% of the world rice crop is used for human food. Although most rice is boiled, a considerable amount is consumed as breakfast cereals. Rice starch also has many uses. Broken rice is used as a livestock feed and for the production of alcoholic beverages. The bran from polished rice is used for livestock feed; the hulls are used for fuel and cellulose. The straw is used for thatching roofs in the Orient and for making paper, mats, hats, and baskets. Rice straw is also woven into rope and used as cordage for bags. This crop serves a multitude of purposes in countries where agriculture is dependent largely upon rice.

Rice is unlike many other cereal grains in that all cultivated varieties belong to the same species and have 12 pairs of chromosomes, as do most wild types. The extent of variation in morphological and physiological characteristics within this single species is greater than for any other cereal crop. See also Genetics.

Rice is an annual grass plant varying in height from 2 to 6 ft (0.6 to 1.8 m). Plants tiller, that is, develop new shoots freely, the number depending upon spacing and soil fertility. The inflorescence is an open panicle. Flowers are perfect and normally self-pollinated, with natural crossing seldom exceeding 3–4%. A distinct characteristic of the flower is the six anthers rather than the customary three of other grasses. Spikelets have a single floret, lemma and palea completely enclosing the caryopsis or fruit, which may be yellow, red, brown, or black. Lemmas may be awnless, partly awned, or fully awned. Threshed rice, which retains its lemma and palea, is called rough rice or paddy. See also Flower; Fruit; Grass crops; Inflorescence; Reproduction (plant).

In the United States, only about 25 varieties are in commercial production. Cultivated rices are classified as upland and lowland. Upland types, which can be grown in high-rainfall areas without irrigation, produce relatively low yields. The lowland types, which are grown submerged in water for the greater part of the season, produce higher yields. In contrast to most plants, rice can thrive when submerged because oxygen is transported from the leaves to the roots. All rice in the United States is produced under lowland or flooded conditions. Rice varieties are also classified as long- or short-grain. Most long-grain rices have high amylose content and are dry or fluffy when cooked, while most short-grain rices have lower amylose content and are sticky when cooked. In the United States a third grain length is recognized: medium-grain. The medium-grain rices have cooking qualities similar to those of short-grain varieties. See also Grain crops.

The rice kernel has four primary components: the hull or husk, the seedcoat or bran, the embryo or germ, and the endosperm. The main objective of milling rice is to remove the indigestible hull and additional portions of bran to yield whole unbroken endosperm. Rice milling involves relatively uncomplicated abrasive and separatory procedures which provide a variety of products dependent on the degree of bran removal or the extent of endosperm breakage.

Instant rice is made from whole grain rice by pretreating under controlled cooking, cooling, and drying conditions to impart the quick-cooking characteristic. Ready-to-eat breakfast rice cereals are prepared from milled rice as flakes or puffs. Rice bran oil was developed as a result of increased extraction of lipids from rice bran. It is utilized as an edible-grade oil in a variety of applications as well as an industrial feedstock for soap and resin manufacture. See also Cereal; Fat and oil (food); Food manufacturing; Solvent extraction.

Grain of Oryza sativa; major food in many countries. Rice when threshed is known as paddy, and is covered with a fibrous husk comprising nearly 40% of the grain. When the husk has been removed, brown rice is left. When the outer bran layers up to the endosperm and germ are removed, the ordinary white rice of commerce or polished rice is obtained (usually polished with glucose and talc).

A 200-g portion of boiled brown rice is a good source of niacin and copper; a source of protein, vitamin B₁, and selenium; provides 1.6 g of dietary fibre; supplies 280 kcal (1180 kJ). A 200-g portion of boiled white rice is a source of niacin and protein; supplies 280 kcal (1180  kJ).

n. This ancient and venerable grain has been cultivated since at least 5000 b.c., and archaeological explorations in China have uncovered sealed pots of rice that are almost 8,000 years old. Today, rice is a staple for almost half the world's population-particularly in parts of China, India, Indonesia, Japan and Southeast Asia. The 7,000-plus varieties of rice are grown in one of two ways. Aquatic rice (paddy-grown) is cultivated in flooded fields. The lower-yielding, lower-quality hill-grown rice can be grown on almost any tropical or subtropical terrain. The major rice-growing states in the United States are Arkansas, California, Louisiana, Mississippi, Missouri and Texas. Rice is commercially classified by its size-long-, medium- or short-grain. The length of long-grain rice is four to five times that of its width. There are both white and brown varieties of long-grain rice, which, when cooked, produce light, dry grains that separate easily. One of the more exotic varieties in the long-grain category is the perfumy East Indian basmati rice. Short-grain rice has fat, almost round grains that have a higher starch content than either the long- or medium-grain varieties. When cooked, it tends to be quite moist and viscous, causing the grains to stick together. This variety (also called pearl rice and glutinous rice, though it's gluten-free) is preferred in the Orient because it's easy to handle with chopsticks. Italian arborio rice-used to make creamy risottos-and the Japanese mochi are also varieties of short-grain rice. Medium-grain rice, as could be expected from its name, has a size and character between the other two. It's shorter and moister than long-grain and generally not as starchy as short-grain. Though fairly fluffy right after being cooked, medium-grain rice begins to clump once it starts to cool. Rice can be further divided into two other broad categories-brown and white. Brown rice is the entire grain with only the inedible outer husk removed. The nutritious, high-fiber bran coating gives it a light tan color, nutlike flavor and chewy texture. The presence of the bran means that brown rice is subject to rancidity, which limits its shelf life to only about 6 months. It also takes slightly longer to cook (about 30 minutes total) than regular white long-grain rice. There is a quick brown rice (which has been partially cooked, then dehydrated) that cooks in only about 15 minutes, and an instant brown rice that takes only 10 minutes. White rice has had the husk, bran and germ removed. Regular white rice is sometimes referred to as polished rice. For converted or parboiled white rice, the unhulled grain has been soaked, pressure-steamed and dried before milling. This treatment gelatinizes the starch in the grain (for fluffy, separated cooked rice) and infuses some of the nutrients of the bran and germ into the kernel's heart. Converted rice has a pale beige cast and takes slightly longer to cook than regular white rice. Talc-coated rice is white rice that has a coating of talc and glucose, which gives it a glossy appearance. The coating acts as a preservative and the practice was once widely used to protect exported rice during long sea voyages. Today coated rice (which is clearly labeled as such) is available only in a few ethnic markets, usually those specializing in South American foods. It must be thoroughly rinsed before being cooked, as there is a chance that the talc can be contaminated with asbestos. Instant or quick white rice has been fully or partially cooked before being dehydrated and packaged. It takes only a few minutes to prepare but delivers lackluster results in both flavor and texture. Rice bran, the grain's outer layer, is high in soluble fiber and research indicates that, like oat bran, it's effective in lowering cholesterol. Rice should be stored in an airtight container in a cool, dark, dry place. White rice can be stored this way almost indefinitely, brown rice up to 6 months. The life of the latter can be extended considerably by refrigeration. Rice can be prepared in a multitude of ways, the method greatly depending on the type of rice. Consult a general cookbook for cooking directions. Rice, which is cholesterol- and gluten-free, is low in sodium, contains only a trace of fat and is an excellent source of complex carbohydrates. Enriched or converted rice contains calcium, iron and many B-complex vitamins, with brown rice being slightly richer in all the nutrients. See also aromatic rice; jasmine rice; rice flour; rizcous; shinma; texmati rice; wehani rice; wild rice; wild pecan rice. rice v. To push cooked food through a perforated kitchen utensil called a ricer. The result is food that looks vaguely ricelike.

(click to enlarge)
Rice (Oryza sativa). (credit: Grant Heilman)

Edible starchy cereal grain and the annual grass (Oryza sativa, family Poaceae, or Gramineae) that produces it. Roughly one-half of the world's population, including almost all of East and Southeast Asia, depends on rice as its principal staple food. First cultivated in India more than 4,000 years ago, rice was planted gradually westward and is now cultivated widely in flooded fields (paddies) and river deltas of tropical, semitropical, and temperate regions. Growing to about 4 ft (1.2 m) in height, rice has long, flat leaves and an inflorescence made up of spikelets bearing flowers that produce the fruit, or grain. Removal of just the husk produces brown rice, containing 8% protein and a source of iron, calcium, and B vitamins. Removal of the bran layer leaves white rice, greatly diminished in nutrients. Enriched white rice has added B vitamins and minerals. So-called wild rice (Zizania aquatica) is a coarse annual grass of the same family whose cereal grain, now often considered a delicacy, has long been an important food of North American Indians.

For more information on rice, visit Britannica.com.

Although mentioned rarely in the standard folklore works, there are several traditions concerning rice. It was a common fallacy amongst sailors that regular use of rice is conducive to blindness, and a slang term for rice on board ship was ‘Strike-me-blind’ (Hazlitt, 1905: 510). Many young women in the 19th century ate quantities of raw rice to improve their complexions (N&Q 11s:3 (1911) 189, 258), while others believed that rice ‘prevents the increase of the population’ and that it was thus given deliberately to Poor Relief claimants (Chambers, 1878: ii. 39).

See also WEDDINGS.

This entry includes three subentries:
The Natural History of Rice
Rice As a Food
Rice As a Superfood

A cereal not used much for animal feed for socioeconomic reasons. The grain also has a low protein content but is otherwise suitable for animal use. Milling by-products are available. Called also Oryza sativa.

• r. flower — see pimelea.