Onion

Description
The onion is believed to have originated in Asia, though it is likely that onions may have been growing wild on every continent. Dating back to 3500 BC, onions were one of the few foods that did not spoil during the winter months. Our ancestors must have recognized the vegetable's durability and began growing onions for food.

The onion became more than just food after arriving in Egypt. The ancient Egyptians worshipped the onion, believing that its spherical shape and concentric rings symbolized eternity. Of all the vegetables that had their images created from precious metals by Egyptian artists, only the onion was made out of gold.

Today, onions are used in a variety of dishes and rank sixth among the world's leading vegetable crops. Onions not only provide flavor; they also provide health-promoting phytochemicals as well as nutrients.

Selection
Most onions are sold loose by the pound, although some types are sold in bags or small boxes. Look for onions that feel dry and solid all over, with no soft spots or sprouts. The neck should be tightly closed and the outer skin should have a crackly feel and a shiny appearance. Onions should smell mild, even if their flavor is not. Avoid selecting onions with green areas or dark patches.

Storage
Onions should be kept in a cool, dry open space away from bright light. Onions do best in an area that allows for air circulation. Because onions absorb moisture, do not store onions below the sink. Also, do not place onions near potatoes because potatoes give off moisture and produce a gas that causes onions to spoil more quickly. Spring/summer onions usually store for about two weeks and storage onions for about three to four weeks.

Varieties
Onions came in a variety of sizes, colors and shapes. They are often broken down into three categories: spring/summer, storage, and pearl onions. Spring/summer onions are grown primarily from fall to spring in warm weather areas and have a soft flesh and a mild or sweet taste. These varieties are generally shipped right after harvesting. Storage onions have a firm flesh, dry, crackly outer skins and have a pungent flavor. After a brief period of drying, these onions are stored for several months before shipping. Pearl onions are often called white onions and are densely planted to make the onions smaller. There are no nutritional differences among these onion types.

Onions also come in three colors — yellow, red, and white. Approximately 88 percent of the onion crop is devoted to yellow onion production, with about 7 percent red onions and 5 percent white onions.

Yellow onions are full-flavored and are a reliable standby for cooking almost anything. Yellow onions turn a rich, dark brown when cooked and give French Onion Soup its tangy sweet flavor. The red onion, with its wonderful color, is a good choice for fresh uses or in grilling and char-broiling. White onions are the traditional onion used in classic Mexican cuisine. They have a golden color and sweet flavor when sautèed.

Source

 * Fruit & Vegetable of the Month: Onions by the US Centers for Disease Control & Prevention, public domain government resource—original source of article