Onions ( Allium cepa L., from Latin cepa "onions"), also known as the red onion bulb or regular onions , are the most widely cultivated vegetables of the genus Allium . His close relatives include garlic, spring onions, chives, and Chinese onions.
The genus also contains several other species which are variously referred to as onions and cultivated for food, such as Japanese onion bunch ( Allium fistulosum ), onion ( A. Ã, ÃÆ' - proliferum ), and the Canadian onion ( Allium canadense ). The name "leek" is applied to a number of species Allium , but A. cepa is exclusively known from cultivation. The original form of his wild ancestors is unknown, though the escape from cultivation has occurred in some areas. Onions are most often a biennial or one yearly plant, but are usually treated as annual and are harvested in the first growing season.
The onion plants have a bluish green hollow leaf fan and the bulb at the base of the plant begins to swell when it reaches a certain length of day. Bulbs consist of compressed and shrunken underground stems surrounded by a modified scale (leaf) that envelops the central bud at the tip of the stem. In autumn (or spring, in the case of red onion), the leaves die and the outer layer of the ball becomes dry and brittle. Plants are harvested and dried and onions ready to be used or stored. This plant is easily attacked by a number of pests and diseases, especially onion flies, onion worms, and various fungi causing decay. Some varieties of A. cepa , such as onion and potato onions, produce many bulbs.
Onions are cultivated and used throughout the world. As a food, they are usually served cooked, as a vegetable or part of a savory dish prepared, but can also be eaten raw or used to make pickles or chutney. They are sharp when chopped and contain certain chemicals that irritate the eyes.
Video Onion
Taxonomy and etymology
Onion plants ( Allium cepa ), also known as onion bulbs or regular onions, are the most widely cultivated species of the genus Allium. It was first officially described by Carl Linnaeus in his 1753 work Species Plantarum . A number of synonyms have emerged in its taxonomic history:
- 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 <- i> - (Metz) Mansf.
A. cepa is known exclusively from cultivation, but related wild species occur in Central Asia. The most closely related species include A. vavilovii (Popov & Vved.) And A. asarense (R.M. Fritsch & amp; Matin) from Iran. However, Zohary and Hopf stated that "there is no doubt whether the collections of A.Ã, vavilovii tested represent the original wild material or just the wild derivatives of the plant."
Most of the A. cepa cultivars are included in the "common onion group" ( A. short Ã, var.Ã, cepa ) and usually called only as "onions". The Aggregatum cultivar group ( A. cepa Ã, var.Ã, aggregatum ) includes shallots and potato onions.
The genus Allium also contains a number of other species that are widely referred to as onions and cultivated for food, such as Japanese onion bunches ( A.a, fistulosum < A. Ã, Ãâ € " proliferum ), and Canadian onions ( A.a, canadense ).
Cepa is generally accepted as Latin for "onion" and has affinity with Ancient Greece: ????? ( kÃÆ'¡pia ), Albania: qepÃÆ' Â «, Aromanian: tseapÃÆ'Â £ , Catalan: ceba , English: chinese, Occitan: ceba , Spanish: Maps Onion
Description
Onion plants have grown and are selectively cultivated for at least 7,000 years. It is a biennial plant, but is usually grown as an annual crop. Modern varieties usually grow to a height of 15 to 45 cm (6 to 18 inches). The leaves are yellowish green to a bluish green and grow alternately in round, fan-shaped form. They are fleshy, hollow, and cylindrical, with one flat side. They are in the widest part about a quarter of the way up, beyond that they are tapering toward the blunt end. The base of each leaf is a flat white sheath, which grows from the basal disk. From the bottom of the disc, a bunch of fibrous roots extends for a short path to the ground. As onions ripen, food reserves begin to accumulate at the base of the leaves and the green onion is swollen.
In autumn, the leaves die back and the bulb outer scales become dry and brittle, so the plants are usually harvested. If left on the ground during the winter, the growing point in the center of the bulbs begins to develop in the spring. New leaves appear and long stems, stocky, hollow expands, topped with a bract that protects the growing flowering. The inflorescence was a round umbel with white flowers with six sections. Its seeds are shiny black and triangular in transverse sections. The average pH of the onion is about 5.5
Usage
Origin and history
Because wild onions are extinct and ancient records use onions stretched across western and eastern Asia, the geographical origin of onions is uncertain, with the possibility of domestication worldwide. Food using onion dates back thousands of years in China, Egypt and Persia.
The restored onion traces of the Bronze Age settlements in China show that onions are used as far as 5000 BC, not only for their flavor, but bulb endurance in storage and transportation. The ancient Egyptians worshiped the onion ball, saw its round shape and concentric circles as symbols of eternal life. Onions are used in Egyptian burials, as evidenced by the onion traces found in the eye socket of Ramesses IV.
Pliny the Elder of the first century CE wrote about the use of onion and cabbage in Pompeii. He documented Roman beliefs about the ability of onions to correct eye diseases, help sleep, and heal everything from mouth sores and toothaches to dog bites, back pain, and even dysentery. Archaeologists dug the old Pompeii castle after his volcanic burial in AD 79, have found a garden similar to Pliny's detailed narrative. According to texts collected in the fifth/sixth centuries under the supervision of the authorial "Apicius" (said to be gourmet), onions are used in many Roman recipes.
In the Age of Discovery, onions were brought to North America by the first European settlers, only to find the plants available, and used extensively in Native American gastronomy. According to the diary kept by the first British colonists, the onion bulb is one of the first plants grown by Pilgrim fathers.
Onion type and product
Normal onions are usually available in three color varieties. Yellow or brown onion (called red in some European countries), full of flavor and onion choice for everyday use, with many cultivars brought up specifically to show this sweetness (Vidalia, Walla Walla, CÃÆ'Â © vennes, "Bermuda," & c.). The yellow onion gets rich, dark brown when caramelized and gives the sweet French onion soup. The onion (called purple in some European countries) is a good choice for fresh use when the color lives on the dish; it is also used in baking. Garlic is a traditional onion used in classic Mexican cuisine; they have a golden color when cooked and a very sweet taste when sautÃÆ'ÂÂ ed.
While large and ripe onion bulbs are most commonly eaten, onions can be eaten at an immature stage. Young plants can be harvested before bulbing occurs and is used entirely as leeks or spring onions. When the onions are harvested after the bulbing has begun, but the onions are not yet ripe, the plants are sometimes referred to as "summer" onions.
In addition, onions can be bred and grow to mature at smaller sizes. Depending on the size of the adult and the purpose of the onion, this can be referred to as pearls, boilers, or onion preservatives, but different from true pearl onions that are different species. Pearly onions and boilers can be cooked as vegetables rather than as ingredients and preservative onions are often preserved in vinegar as a long-lasting meal.
Onions are available in fresh, frozen, canned, caramel, pickled, and chopped forms. Dehydrated products are available in powders, sliced, rings, minced, chopped, granulated, and powdered.
Onion powder is a spice that is widely used when fresh ingredients are not available. Made from finely ground onions, dried onions, especially sharp bulb onion varieties, and have a strong odor. Due to dehydration, it has a long shelf life and is available in several varieties: yellow, red, and white.
Culinary used
Onions are generally chopped and used as ingredients in a variety of warm warm dishes, and can also be used as a main ingredient in their own right, for example in French onion soup, onion cream, and onion chutney. They are versatile and can be roasted, boiled, boiled, roasted, fried, roasted, eaten, or eaten raw in a salad. Their layered nature makes them easy to perforate after cooking, facilitating their stuffing, as in Turkish sogan-dolma.
The pickled onion in vinegar is eaten as a snack around the world, and as a side serving in pubs and fish and chips shops throughout the UK and the Commonwealth. They are part of a traditional English pub lunch, usually served with dry bread, English cheese, and beer.
Similar to garlic, onions can show an additional color - pink - red - after cutting, an effect caused by the reaction of amino acids with sulfur compounds.
Non-culinary use
Onions have very large cells that are easily observed under low magnification. Form a single cell layer, tuber bulbs easily separated for educational, experimental, and breeding purposes.
Onions, therefore, are commonly used in science education to teach the use of microscopes to observe cellular structures.
Onions are poisonous to dogs, cats, guinea pigs, and many other animals.
Composition
Nutrition
Most onion cultivars are about 89% water, 9% carbohydrates (including 4% sugar and 2% dietary fiber), 1% protein, and negligible fats (tables). Onions contain low amounts of essential nutrients and have energy values ​​of 166 kJ (40 Calories) in amounts of 100 g (3.5 oz). Onions provide a savory taste to the dish without contributing to a significant calorie content.
Phytochemicals
A considerable difference exists between the onion varieties in phytochemical content, especially for polyphenols, with the highest onion, six times the amount found in Vidalia onions. The yellow onion has the highest total flavonoid content, 11 times higher than that of garlic. Onions have a considerable content of anthocyanin pigment, with at least 25 different compounds identified representing 10% of the total flavonoid content.
Polyphenols onions are under basic research to determine their biological properties that may be in humans.
Some people suffer from allergic reactions after handling onions. Symptoms may include contact dermatitis, severe itching, rhinoconjunctivitis, blurred vision, bronchial asthma, sweating, and anaphylaxis. Allergic reactions may not occur when eating cooked onions, probably because of the protein denaturation of cooking.
Eye irritation
The freshly cut onions often cause a stinging sensation in the eyes of the people nearby, and often the tears are out of control. This is caused by the release of volatile gas, syn -propanethial-S-oxide, which stimulates the nerve in the eye. This gas is produced by a chain reaction that serves as a defense mechanism: cutting onions causes cellular damage that releases an enzyme called alliinase. It breaks down amino acid sulfoxides and produces sulfenic acid. Specific sulfenic acids, 1-propenesulfenic acid, are rapidly followed up by the second enzyme, the lacrimatory synthase factor, producing syn -propanethial-S-oxide. This gas diffuses through the air and immediately reaches the eye, where it activates the sensory neurons. The lacrimal gland produces tears to dilute and irritate.
Eye irritation can be avoided by cutting onions under running water or submerged in a water basin. Leaving the whole root tip also reduces irritation because the onion base has a higher concentration of sulfur compounds than the rest of the bulb. Cooling the onions before use reduces the rate of enzyme reaction and using the fan can blow the gas from the eye. The more often one piece of onion, the less people get irritated eyes.
The amount of sulfenic acid and lacrimal factor was released and the effects of irritation differed among species Allium . In 2008, the New Zealand Institute for Crop and Food Research created "no tears" of onions by using gene muting biotechnology to prevent synthesis of lachrymatory factor synthesis in onions. One study showed that consumers preferred onion flavor with lower LFS content. However, since the LFS silencing process involves the reduction in sulfur consumption by plants, it has also been suggested that LFS-onions are lower in taste. Methods for differentiating LFS and LFS onions have been efficiently developed based on mass spectrometry, with potential applications in high volume production; Gas chromatography is also used to measure lachrymatory factors in onions. In early 2018, Bayer released the first crop of LFS commercially silenced onions under the name "Sunion." They are the result of 30 years of cross-breeding; genetic modification not used.
Guinea hen weeds and honey garlic contain the same lachrymatory factor. The synthetic onion lachrymatory factor has been used in research related to tear production, and has been proposed as a non-lethal prevention tool against thieves and intruders.
Cultivation
Onions are best grown on well-drained soil. Sandy loams are good because of low sulfur, while clay soils usually have a high sulfur content and produce a stinging bulb. Onions require high levels of nutrients in the soil. Phosphorus is often present in sufficient quantities, but can be applied prior to planting because of its low availability in cold soil. Nitrogen and potassium can be applied periodically during the growing season, the last application of nitrogen at least four weeks before harvest. Bulbing onions is sensitive throughout the day; Their bulbs begin to grow only after the amount of daylight has surpassed some minimal quantity. Most traditional European onions are referred to as long onions, producing bulbs only after 14 hours or more during the day. South European and North African varieties are often known as "intermediate-day" types, requiring only 12-13 hours of daylight to stimulate bulb formation. Finally, short onions, developed in more recent times, are planted in cool autumnous winters and form bulbs in early spring, and require only 11-12 hours of daylight to stimulate bulb formation. Onions are cold-weather plants and can grow in USDA zones 3 to 9. Thermal temperatures or other stress conditions cause them to "bolt", meaning that the flower stalks begin to grow.
Onions can be grown from seeds or from sets. Short-lived onion seeds and fresh seeds germinate better. The seeds are sown thinly in shallow exercises, gradually gradually cultivating the plants. In a suitable climate, certain cultivars can be planted at the end of summer and autumn to withstand winter on the ground and produce early crops the following year. The onion set is produced by sowing the seeds in early summer on bad soil and the small tubers produced are harvested in the fall. These tubers are planted the following spring and grow into a mature tuber at the end of the year. Certain cultivars are used for this purpose and these may not have good storage characteristics such as those grown directly from seeds.
Regular maintenance during the growing season involves keeping the rows free of competing weeds, especially when the plants are young. The plant is rooted in shallow water and does not require much water when it is established. Bulbing usually occurs after 12 to 18 weeks. Tubers can be collected when needed to eat fresh, but if they are to be stored in storage, they must be harvested after the leaves have died naturally. In dry weather, they can be left on the ground for a few days to dry properly, then they can be placed in a net, tied to a string, or placed on a deep in shallow layer. They should be kept in a well-ventilated and cool place like a warehouse.
Pests and diseases
Onions suffer from a number of plant disturbances. The most serious for home gardeners are onion flies, parent tubers and bulbs, white rot, and rotting the neck. Diseases that affect the leaves include rust and spotting, gout, and white tip disease. Tubers can be affected by splitting, white rot, and decaying the neck. Shanking is a condition in which the central leaf becomes yellow and the inside of the bulb collapses into an unpleasantly unpleasant mucus. Most of these disorders are best treated by removing and burning affected plants. Leopard miner larvae or garlic moths ( Acrolepiopsis assectella ) sometimes attack the leaves and can dig into the tubers.
Onion flies ( Delia antiqua ) lay eggs on leaves and stems and on the ground close to onions, onions, spring onions, and garlic plants. Flies are attracted to the plant by the smell of damaged tissue and can occur after thinning. Plants that grow from the set are less susceptible to attack. The larval tunnel to the tubers and foliage wilted and turned yellow. Tubers are damaged and decayed, especially in wet weather. Control measures may include crop rotation, use of seed dressings, early sowing or planting, and removal of infested plants.
The onion eelworm ( Ditylenchus dipsaci ), a small parasitic ground-life parasite, causes swelling, distorted foliage. Young plants are killed and the older ones produce soft bulbs. No known drug and affected plants should be removed and burned. This site should not be used to plant onions again for several years and should also be avoided for growing carrots, parsnips, and nuts, which are also susceptible to eelworms.
White onion, garlic, onion, and garlic were caused by the fungus that was carried away by Sclerotium cepivorum ground. When the roots rot, the leaves turn yellow and wither. Light bulbs are attacked and masked by a soft white mycelial mass, which then results in a small black structure called sclerotia. The structure of this break remains in the ground to infect future plants. There is no cure for this fungal disease, so that the affected plants must be disposed of and destroyed and the soil is used for unrelated plants in subsequent years.
Neck rot is a fungal disease that affects onions in storage. This is due to Botrytis allii , which attacks the neck and upper part of the bulb, causing the gray mold to develop. Symptoms often first occur where the light bulb has been damaged and spreads down on the affected scale. A large number of spores are produced and sclerotia such as crust may also develop. Later, a pile of dried and light bulbs into a dry mummy structure. This disease can be present throughout the growth period, but only manifests itself when the bulb is in storage. An antifungal seed reservoir is available and the disease can be minimized by preventing physical damage to the tubers during harvest, drying and preserving the onions carefully, and proper storage in a cool, dry place with plenty of air circulation.
Home storage
Cooking onions and sweet onions are better kept at room temperature, optimally in one layer, in mesh bags in dry, cool, dark, well-ventilated locations. In this environment, onions have a shelf life of three to four weeks and sweet onions one to two weeks. Cooking onions will absorb odors from apples and pears. Also, they draw moisture from their stored vegetables which can cause them to rot.
Sweet onions have a greater water and sugar content than cooking onions. This makes them sweeter and lighter, but reduces their shelf life. Sweet onions can be stored in the refrigerator; they have a shelf life of about 1 month. Regardless of its type, any piece of onion that is best wrapped tightly, stored away from other products, and used in two to three days.
Variety
Common onion group (var. cepa )
Most of the diversity within A. cepa occurs within this group, the most important plant economically Allium . Plants within this group form large single bulbs, and grow from seeds or set of seeds. The majority of cultivars are grown for dried bulbs, salad onions, and pickled onions belonging to this group. The range of diversity found among these cultivars includes variations in photoperiod (the length of days that trigger bulbing), storage life, taste, and skin color. Common onions range from sharp varieties used for dry soups and onion powder to light sweet and warm onions, such as Vidalia from Georgia, US, or Walla Walla from Washington that can be sliced ​​and eaten raw on a sandwich.
Aggregatum Group (var. aggregatum )
This group contains onion and potatoes, also called as onion multiplier. Bulbs are smaller than regular onions, and one plant forms an aggregate group of bulbs from the master. They are propagated almost exclusively from female bulbs, although reproduction from seeds is possible. Onion is the most important subgroup in this group and consists of the only commercially cultivated cultivars. They form small aggregate groups, narrow ovoid to pear-shaped balls. Potato onions are different from onions in forming larger tubers with fewer tubers per cluster, and have a flat shape (like onions). However, the transitional form exists.
I'itoi onion is a productive multiplier onion cultivated in Baboquivari Peak Wilderness, Arizona area. This type of light bulb has a flavor like onion and is easy to grow and is ideal for hot and dry climates. Tubers are separated, and planted in fall 1 below the surface and 12 in separate. Tubers will multiply into clumps and can be harvested throughout the cold months. The peaks die back in the summer and can come back with heavy rain; the tubers can remain on the ground or harvested and stored in a cool dry place to be planted in the fall. Crops rarely flowering; propagation is by division.
Hybrids with A. cepa origin
A number of cultivated hybrids have a A. cepa offspring, such as diploid onion or onion ( A. ÃÆ'â € " proliferum ), ( A. ÃÆ'â € " cornutum ).
Onions or onion trees produce bulblets in umbels, not flowers, and are now known as hybrids of A. cepa and A. fistulosum . Previously it was treated as a variety of A. cepa , such as A. cepa var. proliferum , A. cepa var. bulbiferum , and A. cepa var. viviparum . It has been planted for centuries in Japan and China for use as an onion salad.
The triploid onion is a hybrid species with three sets of chromosomes, two sets of A. cepa and a third set of unidentified parents. Various triploid onion clones are grown locally in different regions, such as 'Ljutika' in Croatia, and 'Pran', 'Poonch', and 'Srinagar' in Indian-Kashmir region. 'Pran' is growing widely in Jammu and Kashmir province in northern India. There is a very small genetic difference between 'Pran' and Croatian clones 'Ljutika', implying a monophyletic origin for this species.
Some authors have used the name A. cepa var. viviparum (Metzg.) Alef. for the triploid onion, but this name has also been applied to Egyptian onion. The only name that is clearly connected to the triploid onion is A. ÃÆ'â € " cornutum .
Spring onion or onion salad can be grown from Welsh onion ( A. Fistulosum ), and from A. cepa . Young plants from A. fistulosum and A. cepa look very similar, but can be distinguished by its leaves, circular in cross section in A. fistulosum rather than flat on one side.
Production
In 2016, the world's dry production of onions is 93.2 million tons, led by China and India, respectively, producing 26% and 21% of the total.
The Onion Futures Act, passed in 1958, prohibits the trading of futures contracts on onions in the United States. This ban came into effect after farmers complained about allegations of market manipulation by Sam Siegel and Vincent Kosuga at the Chicago Mercantile Exchange two years earlier. Subsequent investigations provided economists with a unique case study into securities futures trading on agricultural prices. This action is still valid starting 2016.
See also
References
Further reading
External links
- Media related to Onions on Wikimedia Commons
- PROTAbase at Allium cepa
Source of the article : Wikipedia
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