Onion is one of the most vital ingredients used in most of the preparations and recipes throughout the whole world. Onion (Allium cepa) is also known as garden onion or bulb onion or shallots and in India it is called by different names regionally like kanda, pyaaz (in Marathi & Hindi), ullipaya (Telugu), neeruli (Kannada) or ulli (Malayalam).
Above ground, the onion shows only a single vertical shoot; the bulb grows underground, and is used for energy storage, leading to the possibility of confusion with a tuber, which it is not. It is a close relative to garlic. The word onion comes from the Latin word unio, which means “single,” or “one”- reflecting the onion plant producing a single bulb, unlike its cousin, the garlic, that produces many small bulbs. The name also describes the onion bulb when cut down the middle; it is a union (also from unio) of many separate, concentrically arranged layers.
Onion, one of the most commonly and popularly used vegetables is a root vegetable used as a seasoning in fresh and dry forms. This underground bulb is known for its distinct/pungent flavor and aroma. It is a most important element of almost every meat dish. But its use is not only confined to the non-vegetarian items, it also mixes well with various vegetables. Onions are almost used in every dish like the soups, stews, fry, curry, sauce, gravies or chutney. Onions are ranked sixth amongst the world’s leading vegetable crops. Onion sambar is a very popular dish prepared in the southern India and onion pakodas are very popularly prepared during the rainy season.
Onions are classified in two categories viz. green (“scallions”) and dry onions. It is believed that this plant has been originated in Asia. It contains protein, sugars, cellulose, minerals, a fixed oil, an essential oil and over 80 per cent water. The whole plant is edible and is used in some form or the other in the food. They are also eaten raw as salad. In European cultures they are rarely eaten on their own, but usually served as accompaniment to the main course. Depending on the variety, an onion can be sharp, spicy, tangy, pungent, mild or sweet.
Could you imagine what would happen without the distinctively pungent smell and taste of onions filling out the flavors of almost every type of cuisine imaginable? It’s almost like the dish is dead and tasteless. The onions look plain but have an intense flavor and are a beloved part of the cuisine of almost every region of the world. There are a variety of onions that purely depends upon on size, color and taste. There are generally two types of large, globe-shaped onions, classified as spring/summer or storage onions. The former class includes those that are grown in warm weather climates and have characteristic mild or sweet tastes. Included in this group are the Maui Sweet Onion (in season April through June), Vidalia (in season May through June) and Walla Walla (in season July and August). Storage onions are grown in colder weather climates and, after harvesting, are dried out for a period of several months, which allows them to attain dry, crisp skins. They generally have a more pungent flavor and are usually named by their color: white, yellow or red. Spanish onions fall into this classification. In addition to these large onions, there are also smaller varieties such as the green onion, or scallion, and the pearl onion.
Onions are a major source of polyphenols in general, and also of flavonoids (a very important subdivision of polyphenols). Red onions are higher in total flavonoids than white onions, (with yellow onions falling somewhere in between).
Onions have been cultivated for over 5000 years ago and are native to Asia and the Middle East. They are highly regarded by the Egyptians. Not only did they use them as currency to pay the workers who built the pyramids, but they also placed them in the tombs of kings, such as Tutankhamen, so that they could carry these gifts bestowed with spiritual significance with them to the afterlife. Onions have been revered throughout time not only for their culinary use, but also for their therapeutic properties. As early as the 6th century, onions were used as a medicine in India. While they were popular with the ancient Greeks and Romans, they were often times dressed with extra seasonings since many people did not find them spicy enough. Yet, it was their pungency that made onions popular among poor people throughout the world that could freely use this inexpensive vegetable to spark up their meals.
Onions were an indispensable vegetable in the cuisines of many European countries during the middle Ages and later even served as a classic healthy breakfast food. The cultivated onion was introduced to North America by Christopher Columbus on his 1492 expedition to Hispaniola. However, they found that strains of wild onions already grew throughout North America. Native American Indians used wild onions in a variety of ways, eating them raw or cooked, as a seasoning or as a vegetable. Such onions were also used in syrups, as poultices, as an ingredient in dyes and even as toys. Onions were also prescribed by doctors in the early 16th century to help with infertility in women, and even dogs, cats and cattle and many other household pets.
Onions are extensively used in India, Pakistan and Iran cuisines and are essential to daily life in the local cuisine. They are commonly used as base for curries, gravies or made into paste and cooked in the main course or side dishes. Onions are also pickled in vinegar and served as a side dish with fish and chips in countries like United Kingdom and Australia. Onions are also used as an aromatic in cooking. They are used along with celery and carrots to flavor stocks, soups, stews and sauces. Onion powder is a spice used for seasoning in cooking. It is made from finely ground dehydrated onions, mainly the pungent varieties of bulb onions, which causes the powder to have a very strong odor.
They contain chemical compounds believed to have anti-inflammatory, anti-cholesterol, anticancer, and antioxidant properties such as quercetin. In India some sects do not eat onion due to its alleged aphrodisiac properties. In many parts of the world, onions are used to heal blisters and boils. Onions may be especially beneficial for women, who are at increased risk for osteoporosis as they go through menopause, by destroying osteoclasts so that they do not break down bone. Onion is a powerful anti-septic that is rich in vitamins A, B and C. It is a potent source of folic acid, calcium, phosphorus, magnesium, chromium, iron and dietary fiber. The health benefits of onions are endless because of its powerful antiseptic and antibacterial properties.
The nutritional values of 100 gm of raw onions are:
Energy: 166kJ (40 kcal)
Carbohydrates: 9.34 g
Sugars: 4.24 g
Dietary fiber: 1.7 g
Fat: 0.1 g
Protein: 1.1 g
Water: 89.11 g