thumb|Cooked white rice
White rice (also known as polished or milled rice) is produced by putting brown rice through a milling process, in which the bran, husk, and germ are removed from the rice grain, resulting in its characteristic white appearance. This removal of the bran layers also significantly reduces its nutritional value as it removes essential nutrients such as fiber, vitamins, and minerals. Milling leaves the grain softer in texture and milder in flavor. The development and spread of white rice over time resulted from historical changes in rice cultivation, trade, and advances in milling technology.
Milling rice
Early milling methods were labor-intensive and involved hand-pounding techniques, with large mortar and pestle type devices resulting in low production and high labor costs. Some versions of this improved uniformity of the product, but with mechanical milling, much larger quantities were produced.
By 1955, new machinery had been developed in Japan that had significantly improved the quality and output capacity. Following these advancements, rice milling continued to develop in order to reduce labor demands while also increasing efficiency and production.
Nutritional content
Cooked white rice is 68% water, 28% carbohydrates, 3% protein, and 0.3% fat (table). In a reference amount of , cooked white rice supplies 130 calories of food energy, and is a rich source (20% or more of the Daily Value, DV) of manganese, and a moderate source of selenium, with no other micronutrients in significant content (table).
Fortification
White rice may be fortified with micronutrients stripped from it during processing. Enrichment of white rice with thiamine, niacin, and iron is required by law in the United States when distributed by government programs to schools, nonprofits, or foreign countries.
Consuming only unenriched white rice may cause beriberi due to a deficiency of thiamine, which caused a major health issue in Japan by the 18th century.
Adopted over brown rice in the second half of the 19th century, white rice was favored by traders because of the removal of the bran and germ which improved its storage life during long distance transports. The expansion of long distance trade contributed to the widespread consumption of white rice in Asia and other regions, as rice spread from East Asia to West Asia and Europe by land and sea via trade routes that later became associated with the Silk Road. Ease of cooking, palatability, and longer shelf life are all reasons white rice became more widely used than brown rice. Historically, in some societies, eating white rice was a symbol of high status due to its scarcity, and it was widely preferred to brown rice in many regions.