Along with garlic, onions have longest history and the evidence of using onions for eating in Egypt of B.C. 4000 is recorded on a mural of an old tomb.
Onions, allium cepa L (scientific name), are wildly raised on the area of West Asia and Afghanistan or Persia is known as the place of origin but it is not clear.
Since the history of the raising is long, climate, cultivation method, kind and other feature of today's onions are too diverse to be compared with those of the original ones.
Their cold-resistant nature enables to be raised almost all over the world. When the pyramids were built in Egypt the year 2500 B.C., onions were exchanged with silver and paid to workers for labor.
This means onions played a steminar-increasing food enough to provide nutrition to laborers, who carried two-ton-weight rocks.
Actually, even though onions have records showing onions have been edible since the long times ago, but for their unique smell, onions were not widely used.
But after times passed, for the very unique smell, onions have been widely used for spice vegetable. Especially, since 1990, studies on medical effects of onions have been actively in process.
Onions are warm and hot. They do not contain poison. They contain medical ingridient and widely used as good sources for cooking. They are easy to be cultivated and stored. Because of their stimulus charateristic, they do nerve stimulation, circulation promotion and sterilization. They also get rid of smell of fish and meat and prevent increase of cholesterol in blood and other associated troubles. Most of all, "Sulf amino" accelates the absorption of Vit.
B and sitimulates metabolism. Because of these features, onions are called young food. Also, Cerenum in onions generates special ingredient, a lot of "Glutachion" for treatment of cancers and prevention effect. "Quersechin", yellow color in skin, prevents spoil of fat and high blood pressure. Since the high effect of sterilization and neutralizing poison, onions have been used in Weastern for the prevention and the treatment of the most scary contagious disease, tuberculosis. Europians, who eat meat mainly, cook food with onions to prevent meat from being spoiled.
1. Reasons for recovering from fatigue and stamina
Because Egyption made slaves to eat onions everyday, they can carry stones to build pyramids even though a stone weigh over two tones. Onions accelerate the absorption of vitamin B1, so that it can promote metabolism to increase the ability of recovering from fatigue and building up stamina.
2. Reasons why Chinese people have less adult diseases.
Even Chinese eat more oily food than Korean, they have less diseases, such as hypertension, sclerosis of the arteries, heart disease, stroke, diabetes, than Korean. The reason is because pecuchin in onions, which is basic material for food for Chinese, resolve cholesterol.
3. Why it cleans our inner body?
Onions act like sponge in our organ and prevent from absorbing excessive nutrition. They grab harmful materials and excretion them to make inner body clean.
4. Reason why it makes liver strong and eyes bright.
If glutachion is lack in our body, the cornea or the eye lens get thick and the function of liver is weaken. Onions have plentiful amounts of glutachion and protect liver and eyes.
5. Reason to be good for diabetes
The result of study by biochemical lab in Merala University, India indicates that the sulfur aminoacid in onions are effective in reducing sugar concentration in blood.
6. Reason of its beneficial reaction to the clear mind and improved memory.
Because onions have the ingredient to improve memory, onions are good for students, especially those who study for tests, and for preventing and treatment dementia in ageing period.
Onions are cold-resistant. The proper temperation for cultivation is 12 20. The temperature for bulbs is slightly higher than this, 20 23 and in the temperature above 25, the growing becomes slow and the leaves are dry. If high temperature is continued, the growing is stopped and goes to dormancy.
Onions are relatively strong to coldness but they will be exposed to the danger of death from cold if the temperature is below -8. In the case of young plants, the proper temperature is 30 and the highest temperature for cultivation is slightly higher than this, 38. The lowest temperature for cultivation is 6 for young plants and 4 for young roots. Because of this, the proper temperature is well controlled when plants are transferred onto the main cultivated land until the transferring is well done..
Higher the temperature is, faster growing is Leaves and trunks. But considering ageing, the proper temperature is below and above 17. When the land temperature is higher until 29, the growing of upper plants and bulbs is faster. But the more amounts can be obtained at 18 24.