Many cultures have evidence of early rice cultivation, including China, India, and the civilizations of Southeast Asia. However, the earliest archaeological evidence comes from central and eastern China and dates to 7000–5000 BCE. More than 90 percent of the world’s rice is grown in Asia, principally in China, India, Indonesia, and Bangladesh, with smaller amounts grown in Japan, Pakistan, and various Southeast Asian nations. Rice is also cultivated in parts of Europe, in North and South America, and in Australia.
Rice processing and uses
rice rice A pile of uncooked rice grains (Oryza sativa). cereal grains cereal grains The kernels of the various cereal grains differ in size and shape, but their structure is similar. The hull is the sheath that encloses the kernel. The bran is the kernel's outer covering. The endosperm (80 to 85 percent of the kernel) is the embryo's food supply if the kernel germinates. The germ contains elements needed for development. When grains are milled, the hull and sometimes the bran is removed. rice noodles rice noodles Rice noodles, common in East Asian cuisine. The harvested rice kernel, known as paddy, or rough, rice, is enclosed by the hull, or husk.
Milling usually removes both the hull and bran layers of the kernel, and a coating of glucose and talc is sometimes applied to give the kernel a glossy finish. Rice that is processed to remove only the husks, called brown rice, contains about 8 percent protein and small amounts of fats and is a source of thiamine, niacin, riboflavin, iron, and calcium. Rice that is milled to remove the bran as well is called white rice and is greatly diminished in nutrients.
When white rice forms a major portion of the diet, there is a risk of beriberi, a disease resulting from a deficiency of thiamine and minerals. Parboiled white rice is specially processed before milling to retain most of the nutrients, and enriched rice has iron and B vitamins added to it. harvested rice harvested rice Stalks of mature rice after harvest in Sulawesi, Indonesia. The milling methods used in most of Asia remain fairly primitive, but large mills operate in Japan and some other areas. Hulling of the paddy is usually accomplished by pestle and mortar worked by hand, foot, or water power. Improvements are slowly taking place. The yield of milled rice is dependent on the size and shape of the grain, the degree of ripeness, and the extent of exposure to the sun. Some large mills, handling 500 to 1,000 tons of paddy daily, have specialized hulling plants with consequent smaller losses from broken grain. They generally employ modern milling techniques and rely on controlled drying plants instead of on sun drying. The by-products of milling, including bran and rice polish (finely powdered bran and starch resulting from polishing), are sometimes used as livestock feed. Oil is processed from the bran for both food and industrial uses. Broken rice is used in brewing, distilling, and in the manufacture of starch and rice flour. Hulls are used for fuel, packing material, industrial grinding, fertilizer manufacture, and in the manufacture of an industrial chemical called furfural. The straw is used for feed, livestock bedding, roof thatching, mats, garments, packing material, and broomstraws.
