Onion is a biennial herb with a superficial root system, a very short flattened stem at the base, which increases in diameter as it grows. All parts of onion produce a strong odor when crushed. Leaves are long, linear and hollow. A bulb is formed by the thickening of the leaf base when the plant reaches a critical stage. The fruit is a spherical capsule.
Onions contain an essential oil and organic sulphides. The scales of onion contain catechol and protocatechuic acid. The odor in onion is due to organic sulphur compounds and is produces only when the tissues are cut or injured by enzyme action on a water soluble amino acid. Heat or freeze drying prevents the enzyme action, so that cooking produces a different odor, flavor and pungency.
Onion is high in food value, moderate in protein content and rich in calcium and riboflavin. There is considerable variation in the composition between different varieties; it also varies with the stage of maturity and the length of storage. Matured onions approximately contain moisture 86.6 percent, protein 1.2 percent, fat 0.1 percent, fiber 0.6 percent, minerals 0.4 percent and carbohydrates 11.1 percent per 100 grams of edible portion. The carbohydrate is principally in the form of sugars. Its mineral and vitamin contents are calcium, iron, phosphorus, carotene, thiamine, riboflavin, niacin and vitamin C.
Botanical Name: Allium cepa
Indian Name: Piyaz
Below are some of the medicinal properties of onion:
- Onion has the property to liquefy phlegm and prevent its recurrence. It has been used as an herbal remedy for centuries in colds, coughs, bronchitis and influenza. Three to four teaspoons of onion juice and honey, mixed in equal proportion can be taken daily in treatment of these conditions. It is one of the safest preventive medicines against common cold during winter.
- Onion is useful in bleeding piles. About 30 grams of onions should be finely ground on a slab with water and 60 grams of sugar added to it. Taken twice daily this brings relief within a few days.
- Onion is noted for its easily assimilable iron content. They are therefore, beneficial in treating anemia.
- It is a valuable remedy for cholera. About 30 grams of onion and seven black peppers can be finely pounded and given to the patient. It allays thirst, restlessness and also lessens vomiting and diarrhea immediately. The addition of a little sugar to the recipe will increase its effectiveness.
- It possessed some germicidal properties. Injection of its juice prevents the development of tuberculosis in animals.
- Cotton wool dipped in onion juice and put into the ear is a popular remedy for noises in the ears. Heated juice dropped in the ear relieves earache.
- It is an important aphrodisiac food. It increases libido and strengthens the reproductory organs. The white variety of onion should be peeled off, crushed and fried in pure butter. This mixture acts as an excellent aphrodisiac tonic if taken regularly with a spoon of honey on an empty stomach.
- Chewing raw onion for 3 minutes is sufficient to kill all germs in the mouth. Toothache is often alleviated by placing a small piece of onion on the affected tooth or gum.
- Onions are very useful in the treatment of the disorders of the urinary system. For burning sensation while passing urine, 6 grams of onion should be boiled in 500 grams of water. When the water is reduced to half, it should be cooled, strained and given to the patient. This relieves the burning sensation. Onion grated with water on a stone slab and mixed with 6o grams of sugar, is effective in treating retention of urine; in brings about free urination within a short time.
White onion is preferable to the red and yellow varieties. Onions should be taken with meals preferably raw, as fried or cooked onions are comparatively difficult to digest. For therapeutic purposes, it is advisable to use onion juice instead of the whole onion. Its being a stimulating and irritating food, one should avoid excess consumption.