Black tomatoes, sometimes called purple tomatoes, have been bred to produce high levels of anthocyanins, a class of pigments responsible for the black and purple colors of many fruits, including blackberries and chokeberries. Anthocyanins have been suggested to have health benefits because of their anti-oxidant properties. The Black color is produced mostly by the anthocyanin petunidin on the outside of the tomato, where the fruit is exposed to direct sunlight. Anthocyanin is a strong pigment with anti-oxidant properties whose purpose is to protect plants from ultraviolet radiation from the sun.