Onions stink due to a chemical change from alliin to sulfur compound
Lifestyle FashionThe onion family is large and diverse, containing more than 500 species. With such a wide range of species, the origins of the modern (or globe) onion are a bit blurry. It has not one, but five possible wild plants it could have evolved from, all of which grow in the Central Asian region.
Bulbs from the onion family are believed to have been used as a food source for millennia. In Bronze Age Palestinian settlements, remains of onions were found alongside fig stones and dates dating back to 5000 BC. C. It would be pure conjecture to suggest that these were cultivated onions. Archaeological and literary evidence suggests that cultivation probably took place around two thousand years later in ancient Egypt. This happened alongside the cultivation of leeks and garlic and it is believed that the slaves who built the pyramids were fed radishes and onions.
“… It is believed that the slaves who built the pyramids were fed radishes and onions.”
It may come as no surprise that it was the Romans who introduced the onion family to Europe. The origins of its name are also Roman or at least Latin. The late Latin name unio was used to describe a species of onion that resembles a single white pearl. This later formed the basis for the French, ‘Onion’ and then the English, ‘Onion’.
Why does the onion family smell? All plants closely related to onion (leeks, shallots, garlic, chives, etc.) contain thioalyl compounds or alliins. When it is cut or crushed, the alliin (an amino acid), within garlic or onion, is converted by an enzymatic reaction into allicin, this is rapidly broken down into sulfur compounds. Sulfur compounds are aromatic and this is what gives all plants in the onion family their distinctive smell. So to put it simply:
o The onion family stinks due to a chemical change from alliin to sulfur compounds and stinks of sulfur.
Onion Family Health and Nutrition:
Garlic contains by far the highest concentration of alliins and has been used medicinally for centuries and has been used as an antiseptic since classical times. The Romans often used garlic and drank a solution of around 5 to 10 bulbs boiled in a small bucket of wine to cure a hangover.
Alliins have also been found to prevent the growth of malignant cells. In other words, they are anticancer and can help prevent cancer cell growth in animals. It has been documented that in areas of high garlic and onion consumption, stomach cancer rates are relatively low.
There is growing evidence that all members of the onion family have a positive effect in reducing the incidence of heart disease. Trials in the mid-1990s showed a drop in the cholesterol levels of a test group when they were given garlic powder.
It would seem that onions play a much more important anti-cancer or cardioprotective role than a nutritional one (see below). However, they add a distinctive taste, smell, and texture to many foods and form the starting stage in many recipes.
Nutrition:
(All medium size), Raw onion, Oil fried onion, Pickled onion
Energy (Kcal) 54 66 4
Protein (g) 1.8 0.9 0.1
Carbohydrate (g) 11.9 5.9 0.7
Sodium (mg) 5 2 68
Calcium (mg) 38 19 3
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Growing onions:
I planted a few sets of onions in August so they will grow through the winter; They should be ready in late spring or early summer. These are the first onions I have ever grown as I have always been able to buy them in bulk cheaply from a nearby Indian store. This year, however, there are only three of us in our house and I found that big bags were a false economy. Most of the time they sprouted or died before I had a chance to eat them all.
In addition to my sets of onions sown in August, I will be growing some from seed in January indoors to plant in April and some from seed outdoors in March. They can also be planted in sets in spring, which will be ready in late August / early September.
The soil must be well prepared for growing onions. Clay soils must be worked in a fine tillage working in abundant organic matter. It may be an idea to prepare the soil before using a green compost such as clover or phacelia. I have planted a phacelia patch for this very reason, ideally it would be planted between March and September, but if you put some in early October it should grow a bit before winter comes.
Most seed packets will give you an idea of planting depth and spacing. I always try to imagine what the plant will look like when it is mature and I give it a little more space than that. Therefore, each onion will be planted at approximately 2 ½ onion sizes from its neighbor. This seems to work with most crops, but they can choke each other if they’re too widely spaced, as the roots need a certain amount of room to grow.