Onion is a term used for many plants in the genus Allium. They are known by the common name "onion" but, used without qualifiers, it usually refers to Allium cepa. Allium cepa is also known as the 'garden onion' or 'bulb' onion and 'shallot'.
Allium cepa is known only in cultivation,[1] but related wild species occur in Central Asia. The most closely-related species include Allium vavilovii Popov & Vved. and Allium asarense R.M. Fritsch & Matin from Iran.[2] However Zohary and Hopf warn that "there are doubts whether the vavilovii collections tested represent genuine wild material or only feral derivatives of the crop.
Onions, one of the oldest vegetables known to humankind, are found in a large number of recipes and preparations spanning almost the totality of the world's cultures. They are nowadays available in fresh, frozen, canned, pickled, powdered, chopped, and dehydrated forms. Onions can be used, usually chopped or sliced, in almost every type of food including cooked foods and fresh salads and as a spicy garnish. They are rarely eaten on their own but usually act as accompaniment to the main course. Depending on the variety, an onion can be sharp, spicy, tangy and pungent or mild and sweet.
Onions pickled in vinegar are eaten as a snack. These are often served as a side serving in fish and chip shops throughout the United Kingdom. Onions are widely-used in India and are fundamental to Indian cooking. They are commonly used as a base for curries or made into a paste and eaten as a main course or as a side dish.
Tissue from onions is frequently used in science education to demonstrate microscope usage, because they have particularly large cells which are readily observed even at low magnifications.
Wide-ranging claims have been made for the effectiveness of onions against conditions ranging from the common cold to heart disease, diabetes, osteoporosis, and other diseases.[9] They contain chemical compounds believed to have anti-inflammatory, anticholesterol, anticancer, and antioxidant properties such as quercetin. However, it has not been conclusively demonstrated that increased consumption of onions is directly linked to health benefits. Some studies have shown that increased consumption of onions reduces the risk of head and neck cancers. [10] In India some sects don't eat onion due to its alleged aphrodisiac properties.
In many parts of the world, onions are used to heal blisters and boils. A traditional Maltese remedy for sea urchin wounds is to tie half a baked onion to the afflicted area overnight. In the morning, the spikes will be in the onion.[citation needed] In the United States, products that contain onion extract are used in the treatment of topical scars; some studies have found their action to be ineffective, [11][12][13] while others found that they may act as an anti-inflammatory or bacteriostatic [14] and can improve collagen organization in rabbits.[15]
Onions may be especially beneficial for women,[16] who are at increased risk for osteoporosis as they go through menopause, by destroying osteoclasts so that they do not break down bone.
An American chemist has stated[17] that the pleiomeric chemicals in onions have the potential to alleviate or prevent sore throat.
Shallots have the most phenols, six times the amount found in Vidalia onion, the variety with the lowest phenolic content. Shallots also have the most antioxidant activity, followed by Western Yellow, pungent yellow (New York Bold™[18]), Northern Red, Mexico, Empire Sweet, Western White, Peruvian Sweet, Texas 1015, Imperial Valley Sweet, and Vidalia. Western Yellow onions have the most flavonoids, eleven times the amount found in Western White, the variety with the lowest flavonoid content.
For all varieties of onions, the more phenols and flavonoids they contain, the more antioxidant and anti-cancer activity they provide. When tested against liver and colon cancer cells, Western Yellow, pungent yellow (New York Bold™[18]) and shallots were most effective in inhibiting their growth. The milder-tasting varieties—Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia—showed little cancer-fighting ability.[18]
Shallots and ten other onion (Allium cepa L.) varieties commonly available in the United States were evaluated: Western Yellow, Northern Red, pungent yellow (New York Bold™), Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia. In general, the most pungent onions delivered many times the benefits of their milder cousins.
500 g.
