Sometimes called purple onions, are cultivated of the onion with purplish red skin and white flesh tinged with red. These onions tend to be medium to large size and have mild to sweet flavor. They are often consumed raw, grilled or lightly cooked with other foods, or added as color to salads, they tend to lose their redness when cooked. Red onions are available throughout the year. The red color comes from anthocyanin’s such as cyanide in. red onions are high in flavonoids.