Table of content A-Z
onion
Botanical name: Allium cepa
The onion is one of our oldest cultivated plants. It has been used for at least 5000 years by the people of Central Asia, Pakistan, north-western India and the Mediterranean countries. Even then it was considered one of the most important vegetables and healing plants. Ancient Egyptian wall paintings and inscriptions from various dynasties witness to the fact that onions, together with radishes and garlic, made up a large part of the victuals for the slaves who built the pyramids. Here in Germany, the onion brought to the countries north of the Alps by Roman soldiers did not become common until the Middle Ages.
Onions are grown today on all continents, preferably in warmer regions.
Availability
Onions can be bought all year round.
Appearance, taste, characteristics
Onions are the underground shoots consisting of thickened bulb scales. Depending on the variety, onions may be flat, oval, pear-shaped, oblong, or globular. The diameter of an onion is usually 46 cm but can be up to 10 cm, again according to the variety. The onion is covered with several layers of dry skin. The onion skin may be white, yellowish, copper-coloured, brown or red-purple. The pulp of the onion is either white or red and usually very juicy. The taste varies with the type from very strong and piquant to fine and mildly sweet.
The botanical species Allium cepa, our onion, comes in many forms. Among them are the following:
* Garden onion (Allium cepa var. cepa)
medium-sized, round onion
pungent, spicy smell and taste
* Shallot (Allium ascabonicum)
earlier, a separate botanical species
form similar to the onion
the finest and mildest species of onion
*Sweet, Vidalia, or Bermuda onion (Allium cepa var. cepa)
grown mainly in southern countries
larger and heavier than the garden onion
mild, sweet taste
* Pearl onion (Allium porrum var. sectivum)
smallest species of onion
rarely sold fresh
used mainly by the food industry
* Silverskin onion (Allium cepa var. cepa)
very similar to the pearl onion
has no skin and is therefore sold only preserved (e.g., mixed pickles)
mild taste
* Spring onion, scallion (Allium fistulosum)
partially developed white onion with fresh greens
looks like a "small leek"
milder in taste than the garden onion
* Red onion (Allium cepa)
thin, red outer skin
mildly spicy, not quite as pungent in taste
imported chiefly from Italy
Ingredients
Onions contain sulphurous, pungent-smelling essential oils that make our eyes tear when we cut them and are responsible for their characteristic smell and taste. They belong to the sulphides.
In folk medicine onions have long been regarded as a remedy for the common cold. They are supposed to have a germicidal and germ-inhibiting effect in the oral cavity and the entire digestive tract.
100 g contain:
|
Zwiebel, fresh |
Zwiebel, cooked |
Perl onion, fresh |
Spring onion, fresh |
Schalotte, fresh |
Pear or silverskin onion, tinned |
|
| Energie (kcal) |
28 |
24 |
76 |
42 |
22 |
62 |
| Wasser (g) |
91 |
92 |
79 |
87 |
93 |
k.A.* |
| Eiweiß (g) |
1 |
1 |
2 |
1 |
1 |
1 |
| Fett (g) |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
< 1 |
| Kohlenhydrate (g) |
5 |
4 |
17 |
9 |
3 |
13 |
| Ballaststoffe (g) |
2 |
2 |
2 |
3 |
2 |
2 |
| Vitamin C (mg) |
8 |
4 |
15 |
25 |
13 |
4 |
| Folsäure (µg) |
17 |
10 |
12 |
17 |
17 |
2 |
| Kalium (mg) |
135 |
76 |
250 |
230 |
334 |
145 |
| Natrium (mg) |
9 |
8 |
8 |
13 |
12 |
225 |
| Calcium (mg) |
31 |
33 |
40 |
140 |
37 |
40 |
| Magnesium (mg) |
11 |
8 |
10 |
11 |
4 |
10 |
| Eisen (mg) |
0,5 |
0,4 |
1,0 |
1,2 |
1,2 |
0,7 |
Quality criteria, optimal storage conditions
Buy only dry, undamaged onions without shoots. Store them in a cool, dark place. Never use a plastic bag to keep them, as they will get mouldy very quickly in it.
Good spring onions have fresh greens. They will keep for about 2 weeks in the refrigerator.
Form of consumption, use, processing, practical tips for preparation
It would be impossible to imagine cooking today without onions, whether raw, cooked, fried or even breaded and deep-fried. In addition to dishes in which they are the main ingredient, such as onion tart or onion soup, they are important as seasoning components of salads, vegetable dishes and stews, sauces or soups.
Do not cut onions until just before you are going to use them. Otherwise they quickly lose their flavour and intensity. The food industry also uses onions in many ways: They are sold dried, powdered, as onion chips or as a juice for seasoning.
Miscellaneous
Tears when cutting onions are unpleasant. Laying the onions in cold water before peeling them is said to help. Another recommendation is to moisten both the cutting board and the knife before cutting the onions.
Be careful when you fry onions; they burn very fast.
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