What would a recipe look like if we didn’t have onions? The distinctive smell and taste of onions round out the flavors of almost any type of cuisine. For centuries, the onion has added value to our cuisine and has also been thought to have therapeutic properties.
The word onion comes from the Latin word unio for “single” or “one” because the onion produces a single bulb. The name also suggests the coming together of the many separate concentrically arranged layers of the onion. Onions are native to Asia and the Middle East and are believed to have been cultivated for more than five thousand years; the ancient Egyptians held them in high esteem. The ancient Egyptians often used them as currency to pay the workers who built the pyramids, and also placed them in the tombs of kings (Tutankhamun) so the kings could take them as gifts in the afterlife. In India, in the 6th century, onions were used as medicine. The ancient Greeks and Romans used to season onions with additional seasonings in their cooking because they didn’t find them spicy enough. Many European countries during the Middle Ages served onions as a classic and healthy breakfast. It should be noted that Christopher Columbus brought onions with him to the West Indies and spread their cultivation from there throughout the Western Hemisphere. Today the main producers of onions are China, the United States, Russia and Spain, among others.
Onions are available in fresh, frozen, canned, and dehydrated form. They can be used in almost any type of food, cooked, in fresh salads or as a garnish, and are usually chopped or chopped. Onions are primarily used as an accompaniment to a main dish and are rarely eaten on their own. There are many different types of onions ranging from sharp and pungent to mild and sweet.
Depending on the variety, onions vary in size, color, and flavor. In general, there are two types of large globe onions, classified as spring/summer or storage onions. The spring/summer class includes onions that are grown in warm climates and have characteristic mild or sweet flavors. This group includes Maui Sweet Onion (in season April through June), Vidalia (in season May through June), and Walla Walla (in season July and August). Storage onions are grown in cooler climates and, after harvest, can be dried for a period of several months. They generally have a spicier flavor and are named for their color: white, yellow, or red. Spanish onions are classified as storage onions. There are also smaller varieties of onions, such as green onions (also called spring onions) and pearl onions.
Onions are members of the Allium family and are rich in powerful sulfur-containing compounds that are responsible for their pungent odors and many beneficial health effects. When an onion is cut, the cells rupture, allowing enzymes called allinases to break down the sulfides and generate sulfenic acids (sulfoxides of amino acids). Sulfenic acids are unstable and break down to produce a gas called syn-propanethial-S-oxide. Then this gas reaches the eye, reacts with the water in the eye to form a dilute solution of sulfuric acid which has irritated the nerve endings in the eye. Your eye then produces tears to dilute and remove the irritating substance. This is what makes your eyes itch and water when you cut onions.
Eye irritation can be reduced by supplying a large amount of water to the reaction, which prevents the gas from reaching the eyes. That is why it is believed that it is useful to chop onions under running water or dip them in a container of water. Rinsing the onion and leaving it moist while slicing can also help. Other tips to help reduce eye irritation are to freeze onions, which prevents the enzymes from activating, limiting the amount of gas that is generated. Also, using a very sharp knife when cutting will limit cell damage and thus reduce the amount of enzymes released. The lemon will help eliminate the characteristic smell of the onion.
As mentioned, it is believed to produce many health benefits. Onions are a good source of chromium, the mineral component of glucose tolerance factor, a molecule that helps cells respond to insulin. Clinical studies with diabetics have shown that the chromium produced by onions can lower fasting blood glucose levels, improve glucose tolerance, lower insulin levels, and lower total cholesterol and triglyceride levels, as well as increase HDL good cholesterol levels.
One cup of raw onion contains more than 20% of the daily value for chromium. Since chromium levels are reduced by consumption of refined sugars, white flour products, and lack of exercise, marginal chromium deficiency is common in the United States.
A case-control study of populations from southern Europe suggests that making onions and garlic a staple in your diet may greatly reduce the risk of several common cancers. Eating onions two or more times per week is associated with a significantly lower risk of developing colon cancer. In addition, regular consumption of onions has been shown to reduce high cholesterol levels and high blood pressure, which helps prevent atherosclerosis and diabetic heart disease, and reduces the risk of heart attack or stroke.
Onions can also help maintain healthy bones. A recently identified compound in onions, gamma-L-glutamyl-trans-S-1-propenyl-cysteine sulfoxide (GPCS), inhibits the activity of osteoclasts (the cells that break down bone). This can be especially beneficial for women who are at higher risk of osteoporosis as they go through menopause.
Other potential health benefits of onions include various anti-inflammatory agents that reduce the severity of symptoms associated with the pain and inflammation of osteoarthritis and rheumatoid arthritis, the allergic inflammatory response of asthma, and respiratory congestion associated with the common cold . Additionally, the quercetin and other flavonoids found in onions work with vitamin C to help kill harmful bacteria and are helpful when added to soups and stews during cold and flu season.
In many parts of the underdeveloped world, onions are also useful for curing blisters and boils. Onion extract (Mederma) is used in the United States in the treatment of topical scars.
When choosing onions, choose onions that are clean, have no opening in the neck, and have a crisp, dry outer skin. Avoid onions that have sprouted, have signs of mold, or have soft spots, moisture on the neck, and dark spots that may indicate signs of decay. When choosing chives, choose those with fresh green tops that are crisp and tender. They should be white 2-3″ along the base. Avoid scallions that look wilted or have yellow tops.
Store onions at room temperature, away from bright light, and in a well-ventilated area. Ideally, hang them in a wire basket or perforated container to ventilate. Onions that have a more pungent flavor, such as yellow onions, can be stored for longer periods than sweeter varieties of onions, such as white onions. Chives should be stored in a plastic bag in the refrigerator and will keep well for about a week. Store all onions away from potatoes, as the onions will absorb moisture from the potatoes and make them spoil more easily. Cut onions should be wrapped tightly in plastic wrap or sealed in a container, and used within a couple of days, as they tend to oxidize and lose their nutritional value quickly. To maintain the best flavor of cooked onions, they should be stored in an airtight container and used within a few days. Never place cooked onions in a metal container as this will cause discoloration. Peeled and chopped onions can be frozen raw, but this can cause them to lose some of their flavor.
Onions can be eaten raw or cooked in just about any way imaginable: roasted, boiled, baked, creamed, fried, fried, or pickled. They are great in soups, stews, and combined with meats and vegetables. They add a versatility to your dishes that is hard to beat.