Onion

The onion (Allium cepa) is a bulb vegetable in the Amaryllidaceae family, alongside garlic, leek and chives. The part we usually eat is a bulb, a short underground stem surrounded by fleshy leaf bases that store nutrients. Above the soil, the plant develops hollow, tubular leaves. If it is left to grow for a second season, the onion can produce a tall flowering stalk topped by a rounded cluster of small flowers, which later forms seeds.

Onions grow best in fertile, well-drained soil with regular moisture during active growth. Different varieties produce bulbs of different sizes and colors, including white, yellow, brown and red or purple. Their flavor also varies, from mild and sweet to strongly pungent. Onions are widely used in cooking because they add aroma and flavor to many dishes.

They can be eaten raw or cooked, and may be sliced, chopped, grilled, roasted, fried or slowly caramelized. When an onion is cut, damaged cells release sulfur-containing compounds that react with enzymes and form irritating substances. These compounds can stimulate the eyes to produce tears. Onions also provide dietary fiber, vitamin C, folate and various plant compounds, including flavonoids such as quercetin.

Their nutritional composition depends on the variety and preparation method. Stored correctly in a cool, dry and well-ventilated place, many mature onions can keep for several weeks or months. As part of a varied diet, onions are a simple way to add both flavor and plant foods to everyday meals.