t onion
Onions are rich in vitamin C, quercetin (a polyphenol antioxidant), and prebiotic inulin fiber, with additional sulfur compounds linked to anti-inflammatory and cardiovascular benefits. One medium raw onion contains approximately 45 calories and is very low in fat.
About
The onion (Allium cepa) is a bulbous perennial plant in the amaryllis family, native to Central Asia and cultivated worldwide for millennia. The edible bulb consists of fleshy, overlapping leaves (layers) that form a rounded or flattened base, enclosed in papery skin ranging from white to yellow, red, or purple depending on variety. Onions are characterized by their pungent, sulfurous compounds (thiosulfates and sulfoxides) that create their distinctive sharp, acrid flavor when raw, which becomes sweet and mellow when cooked as these volatile compounds break down through heat. Major varieties include yellow storage onions (most common, with assertive flavor), white onions (milder, sharper), red/purple onions (sweeter, more delicate), and sweet onions such as Vidalia and Walla Walla (high sugar content, low sulfur compounds).
Culinary Uses
Onions are one of the most fundamental aromatic vegetables in global cuisine, serving as a flavor base in countless dishes. They are routinely diced and sautéed as the foundational layer for soups, stews, sauces, and braises across French, Italian, Latin American, Asian, and Middle Eastern cooking traditions. Raw onions appear in salads, salsas, and pickled preparations, providing sharp contrast and textural interest. Caramelization of onions—a slow cooking process lasting 30–45 minutes—produces deep umami sweetness, essential in French onion soup and many Mediterranean dishes. Grilled or roasted onion wedges become tender and develop complex, charred flavors. Pearl onions and cipollini varieties are favored whole in braises and glazes.