Red onions have a red to dark purple skin. They have a mild flavor and a slightly sweet aroma. Red onions are good raw in salads and are also used as an ingredient for soups and sauces.
From Wikipedia: “Red onions, are cultivars of the onion (Allium cepa) with purplish red skin and white flesh tinged with red.
These onions tend to be medium to large in size and have a mild, to sweet flavor. They are often consumed raw, grilled or lightly cooked with other foods, or added as a decoration to salads. They tend to lose their colour when cooked.
Red onions are available throughout the year. The red colour comes from anthocyanidins such as cyanidin. Red onions are high in flavonoids, including quercetin, and fibre, (compared to white and yellow onions). Red onions also can help remove bad cholesterol.”
Popular red onion cultivars:
- Red onion of Turda: “The red onion from Turda (Cluj County, Central Romania) (Romanian: "Ceapa de Turda") is a local variety of red onion with light sweeter taste and particular aroma. The area of cultivation encompass the lower Arieş valley and the middle Mureş valley. Turda onion bulbs are traditionally intertwined into long strings (1–2 m) for marketing purposes and can be found at the traditional markets all over central Romania. "Turda Red Onion" is usually served fresh, as a salad or part of mixed salads and especially as a compulsory garnish for the traditional bean-and-smoked ham soups.”
- Red onion of Tropea: “The red onion from Tropea, Italy, (Italian: "Cipolla Rossa di Tropea") is a particular variety of red onion which grows in a small area of Calabria in southern Italy named Capo Vaticano near the city of Tropea. This onion has a stronger and sweeter aroma and the inner part is juicier and whiter than other red onions and it is possible to make a jam with it. In March 2008, the European Union registered the Protected Designation of Origin mark for the red onions produced in this particular area.”
- Wethersfield red onion: “In the United States, one of the most prominent cultivars of red onion was grown in Wethersfield, Connecticut, and was a major source of onions for New England until the late 1800s.”
Nutrients and phytochemicals:
From “https://en.wikipedia.org/wiki/Onion”: “Most onion cultivars are about 89% water, 9% carbohydrates (including 4% sugar and 2% dietary fiber), 1% protein, and negligible fat. Onions contain low amounts of essential nutrients and have an energy value of 166 kJ (40 Calories) in a 100 g (3.5 oz) amount. Onions contribute savory flavor to dishes without contributing significant caloric content.”
“Considerable differences exist between onion varieties in phytochemical content, particularly for polyphenols, with shallots having the highest level, six times the amount found in Vidalia onions. Yellow onions have the highest total flavonoid content, an amount 11 times higher than in white onions. Red onions have considerable content of anthocyanin pigments, with at least 25 different compounds identified representing 10% of total flavonoid content.
Onion polyphenols are under basic research to determine their possible biological properties in humans.”
“They can be stored 3 to 4 months at room temperature.”
From “https://en.wikipedia.org/wiki/Onion”: “Some people suffer from allergic reactions after handling onions. Symptoms can include contact dermatitis, intense itching, rhinoconjunctivitis, blurred vision, bronchial asthma, sweating, and anaphylaxis. Allergic reactions may not occur when eating cooked onions, possibly due to the denaturing of the proteins from cooking.”
“In the 19th century, the skin of red onions was used to dye eggs.”