History:- The word onion comes from the Latin word unio means large pearl, which in Middle English became union and then onion. In Bronze Age, traces of onion remains were found dating back to 5000 BC. The Ancient Egyptians worshipped it, believing that its spherical shape and concentric rings symbolized eternal life. In ancient Greece, athletes ate large quantities of onion to lighten the balance of blood. Roman gladiators were rubbed down with onion to firm up their muscles. In the Middle Ages, onion was very important so that people were paying their rent with onions. The onion was introduced to North America by Christopher Columbus on his 1492 expedition. Onions were also prescribed by doctors in the early 16th century to help with infertility in women.

Uses:- Onions are found in a large number of recipes and preparations. The whole plant is edible and is used as food. They are now available in fresh, frozen, canned, caramelized, 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. Onions are commonly used as a base for curries or made into a paste and eaten as a main course or as a side dish.

Medicinal Properties:- A raw onion has the followings nutrients.

Energy, Carbohydrates, Sugars, Dietary fiber, Fats, Protein, Water, Vitamin A , Thiamine (Vit. B1), Riboflavin (Vit. B2), Niacin (Vit. B3), Vitamin B6, Folate (Vit. B9), Vitamin B12

Vitamin C, Vitamin E, Vitamin K, Calcium, Iron, Magnesium, Phosphorus, Potassium, Sodium, Zinc

Health Effects:- The onions are very much effective in common cold, heart disease, diabetes, osteoporosis, and many other diseases. They contain the chemical compounds such as quercetin with antiinflammatory, anticholesterol, anticancer, and antioxidant properties. Studies have shown that increased consumption of onions reduces the risk of head and neck cancers. It is also believed that eating onions can lead to weight loss. In many parts of the world, onions are used to heal blisters and boils. An application of raw onion is also said to be helpful in reducing swelling from bee stings. Onions may be especially beneficial for women having osteoporosis.

Cultivation:- Onions generally come in three colors:- yellow, red, and white. Yellow onions are full-flavored and are a reliable standby for cooking almost anything. The red onion, with its wonderful color, is a good choice for fresh uses. White onions are the traditional onion. Onions are grown from seed or from sets started from seed.

Onion & Eye Irritation:- As onions are sliced or eaten, its cells are broken, allowing enzymes called alliinases to break down amino acid sulphoxides and generate sulphenic acids. A specific sulfenic acid is rapidly rearranged by a second enzyme, called the lachrymatory factor synthase, giving a volatile gas known as the onion lachrymatory factor or LF. The LF gas diffuses through the air and eventually reaches the eye, where it activates sensory neurons, creating a stinging sensation. Tear glands produce tears to dilute and flush out the irritant. Supplying ample water, while peeling onions, prevents the gas from reaching the eyes. Eye irritation can, therefore, be avoided by cutting onions under running water or submerged in water.  Another way to reduce irritation is by chilling or freezing as it  prevents the enzymes from activating, limiting the amount of gas generated.

Production:- The top 10 onion producers in the world are India, China, Australia, US,  Turkey, Pakistan, Russia, South Korea, Japan and Spain.