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Version actuelle datée du 17 juillet 2022 à 13:45

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Botanique et agriculture

Le grain est le fruit (caryopse) et la semence des céréales. En agriculture céréalière, il désigne souvent le grain de blé.

Métrologie

  • Le grain est une unité ancienne, soit de masse ({{safesubst:#invoke:Unité|unite}}), soit de longueur. L'unité de masse est toujours utilisée de nos jours pour mesurer la poudre des cartouches d'arme à feu, ainsi que pour les perles et les diamants ;
  • La granulométrie permet la classification des différents types de grains selon leurs tailles.

Météorologie

En météorologie maritime, un grain est un vent violent et de courte durée qui s'élève soudainement et qui est généralement accompagné de précipitations.

Patronyme

Modèle:Nom de famille

Autres


Various food grains at a market in India

A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption.[1] A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes.

After being harvested, dry grains are more durable than other staple foods, such as starchy fruits (plantains, breadfruit, etc.) and tubers (sweet potatoes, cassava, and more). This durability has made grains well suited to industrial agriculture, since they can be mechanically harvested, transported by rail or ship, stored for long periods in silos, and milled for flour or pressed for oil. Thus, the grain market is a major global commodity market that includes crops such as maize, rice, soybeans, wheat and other grains.

Grains and cereal

Grains and cereal are synonymous with caryopses, the fruits of the grass family. In agronomy and commerce, seeds or fruits from other plant families are called grains if they resemble caryopses. For example, amaranth is sold as "grain amaranth", and amaranth products may be described as "whole grains". The pre-Hispanic civilizations of the Andes had grain-based food systems, but at higher elevations none of the grains was a cereal. All three grains native to the Andes (kaniwa, kiwicha, and quinoa) are broad-leafed plants rather than grasses such as corn, rice, and wheat.[2]

Classification

Illustration of a wheat kernel, its composition and the nutritional values of its parts.

Cereal grains

Harvesting a cereal with a combine harvester accompanied by a tractor and trailer.
Cereal grains: (top) pearl millet, rice, barley
(middle) sorghum, maize, oats
(bottom) millet, wheat, rye, triticale

A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize. Edible grains from other plant families, such as buckwheat and quinoa, are pseudocereals. Most cereals are annuals, producing one crop from each planting, though rice is sometimes grown as a perennial. Winter varieties are hardy enough to be planted in the autumn, becoming dormant in the winter, and harvested in spring or early summer; spring varieties are planted in spring and harvested in late summer. The term cereal is derived from the name of the Roman goddess of grain crops and fertility, Ceres.

Cereals were domesticated in the Neolithic, some 8,000 years ago. Wheat and barley were domesticated in the Fertile Crescent; rice was domesticated in East Asia, and sorghum and millet were domesticated in West Africa. Maize was domesticated by Indigenous peoples of the Americas in southern Mexico about 9,000 years ago. In the 20th century, cereal productivity was greatly increased by the Green Revolution. This increase in production has accompanied a growing international trade, with some countries producing large portions of the cereal supply for other countries.

Cereals provide food eaten directly as whole grains, usually cooked, or they are ground to flour and made into bread, porridge, and other products. Cereals have a high starch content, enabling them to be fermented into alcoholic drinks such as beer. Cereal farming has a substantial environmental impact, and is often produced in high-intensity monocultures. The environmental harms can be mitigated by sustainable practices which reduce the impact on soil and improve biodiversity, such as no-till farming and intercropping.

Warm-season cereals

Cereal grain seeds clockwise from top-left: wheat, spelt, oat, barley.

Cool-season cereals

Barley
Rye grains
Rice grains by the IRRI

Pseudocereal grains

Buckwheat

Starchy grains from broadleaf (dicot) plant families:

Pulses

Lentil

Pulses or grain legumes, members of the pea family, have a higher protein content than most other plant foods, at around 20%, while soybeans have as much as 35%. As is the case with all other whole plant foods, pulses also contain carbohydrates and fat. Common pulses include:

Oilseeds

Oilseed grains are grown primarily for the extraction of their edible oil. Vegetable oils provide dietary energy and some essential fatty acids.[3] They are also used as fuel and lubricants.[4]

Mustard family

Rapeseed

Aster family

Sunflower seeds

Other families

Ancient grains

Wild cereals and other wild grasses in northern Israel

Ancient grains is a marketing term used to describe a category of grains and pseudocereals that are purported to have been minimally changed by selective breeding over recent millennia, as opposed to more widespread cereals such as corn, rice and modern varieties of wheat, which are the product of thousands of years of selective breeding. Ancient grains are often marketed as being more nutritious than modern grains, though their health benefits over modern varieties have been disputed by some nutritionists.[5][6]

Ancient grains include varieties of wheat: spelt, Khorasan wheat (Kamut), einkorn, and emmer; the grains millet, barley, teff, oats, and sorghum; and the pseudocereals quinoa, amaranth, buckwheat, and chia.[5][6][7][8][9][10] Some authors even consider bulgur and freekeh to be ancient grains,[11] even though they are usually made from ordinary wheat. Modern wheat is a hybrid descendant of three wheat species considered to be ancient grains: spelt, einkorn, and emmer.[6][7]

Historical importance

Because grains are small, hard and dry, they can be stored, measured, and transported more readily than can other kinds of food crops such as fresh fruits, roots and tubers. The development of grain agriculture allowed excess food to be produced and stored easily which could have led to the creation of the first temporary settlements and the division of society into classes.[12]

This assumption that grain agriculture led to early settlements and social stratification has been challenged by James Scott in his book Against the Grain.[13] He argues that the transition from hunter-gatherer societies to settled agrarian communities was not a voluntary choice driven by the benefits of increased food production due to the long storage potential of grains, but rather that the shift towards settlements was a coerced transformation imposed by dominant members of a society seeking to expand control over labor and resources.

Trade

The grain trade refers to the local and international trade in cereals such as wheat, barley, maize, and rice, and other food grains. Grain is an important trade item because it is easily stored and transported with limited spoilage, unlike other agricultural products. Healthy grain supply and trade is important to many societies, providing a caloric base for most food systems as well as important role in animal feed for animal agriculture.

The grain trade is as old as agricultural settlement, identified in many of the early cultures that adopted sedentary farming. Major societal changes have been directly connected to the grain trade, such as the fall of the Roman Empire. From the early modern period onward, grain trade has been an important part of colonial expansion and international power dynamics. The geopolitical dominance of countries like Australia, the United States, Canada and the Soviet Union during the 20th century was connected with their status as grain surplus countries.

More recently, international commodity markets have been an important part of the dynamics of food systems and grain pricing. Speculation, as well as other compounding production and supply factors leading up to the 2007–2008 financial crises, created rapid inflation of grain prices during the 2007–2008 world food price crisis. More recently, the dominance of Ukraine and Russia in grain markets such as wheat meant that the Russian invasion of Ukraine in 2022 caused increased fears of a global food crises in 2022. Changes to agriculture caused by climate change are expected to have cascading effects on global grain markets.[14][15][16][17]

Occupational safety and health

Those who handle grain at grain facilities may encounter numerous occupational hazards and exposures. Risks include grain entrapment, where workers are submerged in the grain and unable to remove themselves;[18] explosions caused by fine particles of grain dust,[19] and falls.

See also

References

  1. ^ Babcock, P. G., ed. 1976. Webster's Third New Dictionary. Springfield, Massachusetts: G. & C. Merriam Co.
  2. ^ Lost Crops of the Incas: Little-Known Plants of the Andes with Promise for Worldwide Cultivation. Office of International Affairs, National Academies of the. Washington D.C.: National Academy Press. 1989. p. 24. doi:10.17226/1398. ISBN 978-0-309-04264-2.
  3. ^ Lean, M.E.J. (2006). Fox and Cameron's Food Science, Nutrition & Health, 7th Edition. CRC Press. p. 49. ISBN 978-1-4441-1337-2.
  4. ^ Salunkhe, D. K. (1992-02-29). World Oilseeds. Springer Science & Business Media. ISBN 9780442001124.
  5. ^ a b Conis, Elena (19 February 2011). "Ancient grains: The best thing since sliced bread?". Los Angeles Times. Retrieved 22 October 2015.
  6. ^ a b c Joanna Jolly (16 December 2014). "Why do Americans love ancient grains?". BBC News. Retrieved 19 October 2015.
  7. ^ a b Clark, Melissa (13 March 2015). "Know Your Heirloom and Ancient Grains". The New York Times. Retrieved 22 October 2015.
  8. ^ Dan Charles (8 December 2014). "'Ancient Grains' Go From Fringe Food To New Cheerios Variety : The Salt". NPR. Retrieved 22 October 2015.
  9. ^ Vara, Vauhini (24 October 2014). "Why We're Willing to Pay More for Cereals with Ancient Grains". The New Yorker. Retrieved 22 October 2015.
  10. ^ Zevnik, Neil (7 January 2014). "Ancient Grains: Everything Old Is New Again". Huffingtonpost.com. Retrieved 13 November 2015.
  11. ^ Charlie Fox, Freekeh Recipes: A Guide to Cooking with this Ancient Grain, 2020
  12. ^ Wessel, T. (1984). "The Agricultural Foundations of Civilization". Journal of Agriculture and Human Values. 1 (2): 9–12. doi:10.1007/BF01530609.
  13. ^ Scott, James (2017). Against the Grain: A Deep History of the Earliest States. Yale University Press. ISBN 9780300240214.
  14. ^ Pei, Qing; Zhang, David Dian; Xu, Jingjing (August 2014). "Price Responses of Grain Market under Climate Change in Pre-industrial Western Europe by ARX Modelling". Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications. pp. 811–817. doi:10.5220/0005025208110817. ISBN 978-989-758-038-3. S2CID 8045747.
  15. ^ "Climate Change Is Likely to Devastate the Global Food Supply". Time. Retrieved 2022-04-02.
  16. ^ "CLIMATE CHANGE LINKED TO GLOBAL RISE IN FOOD PRICES – Climate Change". Archived from the original on 18 October 2022. Retrieved 2022-04-02.
  17. ^ Lustgarten, Abrahm (2020-12-16). "How Russia Wins the Climate Crisis". The New York Times. ISSN 0362-4331. Retrieved 2022-04-02.
  18. ^ "Frequently Asked Questions About Flowing Grain Entrapment, Grain Rescue and Strategies, and Grain Entrapment Prevention Measures" (PDF). Agricultural Safety and Health Program, Purdue University. April 2011. p. 1. Archived from the original (PDF) on December 17, 2013. Retrieved November 4, 2012.
  19. ^ Occupational Safety and Health Administration. "Combustible Dust in Industry: Preventing and Mitigating the Effects of Fire and Explosions". Safety and Health Information Bulletin. United States Department of Labor. Retrieved 29 October 2013.