• Onions


    • Onion
      Mixed onions.jpg
      Scientific classification
      Kingdom: Plantae
      Clade: Angiosperms
      Clade: Monocots
      Order: Asparagales
      Family: Amaryllidaceae
      Subfamily: Allioideae
      Genus: Allium
      Species: A. cepa
      Binomial name
      Allium cepa
      Stereo image
      Right frame 
      Onion seeds have a very distinct shape.
      Raw onion bulbs
      Nutritional value per 100 g (3.5 oz)
      Energy 166 kJ (40 kcal)
      9.34 g
      Sugars 4.24 g
      Dietary fiber 1.7 g
      0.1 g
      1.1 g
      Thiamine (B1)
      0.046 mg
      Riboflavin (B2)
      0.027 mg
      Niacin (B3)
      0.116 mg
      Pantothenic acid (B5)
      0.123 mg
      Vitamin B6
      0.12 mg
      Folate (B9)
      19 μg
      Vitamin C
      7.4 mg
      23 mg
      0.21 mg
      10 mg
      0.129 mg
      29 mg
      146 mg
      0.17 mg
      Other constituents
      Water 89.11 g
      Fluoride 1.1 µg

      Percentages are roughly approximated using US recommendations for adults.
      Source: USDA Nutrient Database

      The onion (Allium cepa L., from Latin cepa "onion"), also known as the bulb onion or common onion, is a vegetable and is the most widely cultivated species of the genus Allium.

      This genus also contains several other species variously referred to as onions and cultivated for food, such as the Japanese bunching onion (Allium fistulosum), the tree onion (A. ×proliferum), and the Canada onion (Allium canadense). The name "" is applied to a number of Allium species, but A. cepa is exclusively known from cultivation. Its ancestral wild original form is not known, although escapes from cultivation have become established in some regions. The onion is most frequently a biennial or a perennial plant, but is usually treated as an annual and harvested in its first growing season.

      The onion plant has a fan of hollow, bluish-green leaves and its bulb at the base of the plant begins to swell when a certain day-length is reached. The bulbs are composed of shortened, compressed, underground stems surrounded by fleshy modified scale (leaves) that envelop a central bud at the tip of the stem. In the autumn (or in spring, in the case of overwintering onions), the foliage dies down and the outer layers of the bulb become dry and brittle. The crop is harvested and dried and the onions are ready for use or storage. The crop is prone to attack by a number of pests and diseases, particularly the onion fly, the onion eelworm, and various fungi cause rotting. Some varieties of A. cepa, such as shallots and potato onions, produce multiple bulbs.

      Onions are cultivated and used around the world. As a food item, they are usually served cooked, as a vegetable or part of a prepared savoury dish, but can also be eaten raw or used to make pickles or chutneys. They are pungent when chopped and contain certain chemical substances which irritate the eyes.

      Top Ten Onions (dry) Producers — 2012 (metric tons)
       China 20,507,759
       India 13,372,100
       United States 3,320,870
       Egypt 2,208,080
       Iran 1,922,970
       Turkey 1,900,000
       Pakistan 1,701,100
       Brazil 1,556,000
       Russia 1,536,300
       Republic of Korea 1,411,650
      World Total 74,250,809
      Source: UN Food & Agriculture Organisation (FAO)

      • Allium cepa var. aggregatum – G. Don
      • Allium cepa var. bulbiferum – Regel
      • Allium cepa var. cepa – Linnaeus
      • Allium cepa var. multiplicans – L.H. Bailey
      • Allium cepa var. proliferum – (Moench) Regel
      • Allium cepa var. solaninum – Alef
      • Allium cepa var. viviparum – (Metz) Mansf.
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