Onions, one of the oldest vegetables known to humankind, are found in a bewildering array of recipes and preparations. There are three types of onions; spring, storage and pearl. Spring onions are grown from fall to spring, and have a mild taste. They are shipped immediately after harvest.Storage onions are firm, dry and possess a pungent taste. After harvest, they are dried and then shipped while Pearl onions are white, small, and mild in taste.
Onions are low in calories and nutrients except in vitamin A in scallions (green onions). Photochemicals in onions promote health, and quercetin acts as an antioxidant.