Red onion
A red onion
SpeciesAllium cepa
Cross sections of red onions

Red onions (also known as purple or blue onions in some mainland European countries) are cultivars of the onion (Allium cepa), and have purplish-red skin and white flesh tinged with red. They are most commonly used in cooking, but the skin has also been used as a dye.[1]

Red onions tend to be medium to large in size and have a sweeter flavor than white or yellow onions due to low levels of pyruvic acid and sulfur compounds. They are often consumed raw (and can be added to salads for color and bite), grilled, or lightly cooked with other foods.[2] Red onions are available throughout the year and are high in flavonoids[3] and fiber (compared to white and yellow onions).[4] Cut red onion can be soaked in cool water for a period of time, and the water can be drained off, resulting in less "bite" and pungency.[5]



Rossa di Tropea for sale in Italy

The red onion from Tropea, Italy, (Italian: "Cipolla Rossa di Tropea") grows in a small area of Calabria in southern Italy, Capo Vaticano, near the city of Tropea.[6] 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 July 2007, the European Union registered the Protected geographical indication mark for the red onions produced in this particular area in Italy.[7]


The red onion from Turda (Cluj County,[8] Central Romania) (Romanian: "Ceapa de Turda",[9]) is a local variety of red onion with light sweeter taste and particular aroma. The area of cultivation encompass the lower Arieș valley and the middle Mureș valley.[citation needed]

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.[citation needed]


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.[10][11]


  1. ^ Ernest Small, Top 100 Food Plants, p. 367, at Google Books
  2. ^ "Glossary". Retrieved 28 June 2017.
  3. ^ Gennaro, Laura; Leonardi, Cherubino; Esposito, Fabrizio; Salucci, Monica; Maiani, Giuseppe; Quaglia, Giovanni; Fogliano, Vincenzo (2002). "Flavonoid and Carbohydrate Contents in Tropea Red Onions: Effects of Homelike Peeling and Storage". Journal of Agricultural and Food Chemistry. 50 (7): 1904–1910. doi:10.1021/jf011102r. PMID 11902931.
  4. ^ Bill Jones The Deerholme Vegetable Cookbook, p. 24, at Google Books
  5. ^ "Take the Bite Out of Raw Onions".
  6. ^ "Flavour of the Med - 6 August 2004". CatererSearch. 6 August 2004. Retrieved 19 September 2013.
  7. ^ "'CIPOLLA ROSSA DI TROPEA CALABRIA' - Official Journal of the European Union". EUR-lex. 13 July 2007. Archived from the original on 27 January 2024. Retrieved 26 January 2024.
  8. ^ OANCEA, SIMONA; DRĂGHICI, OLGA (May 2013). "pH and Thermal Stability of Anthocyanin-based Optimised Extracts of Romanian Red Onion Cultivars". Czech Journal of Food Sciences. 31 (3): 283–291. doi:10.17221/302/2012-CJFS.
  9. ^ "Onion Turda on the Harvest Day in Cluj" (in Romanian). Retrieved 30 June 2017.
  10. ^ "A Great Trade Vanished. How Connecticut's Onion Monopoly Was Lost", The New York Times, 2 June 1889
  11. ^ "Wethersfield, CT, and Onions", Yankee Magazine, August 1993