Blue tomatoes are tomatoes that have been bred to produce high levels of anthocyanin, a pigment responsible for the blue and purple color of many fruits including blueberries, blackberries and chokeberries. Anthocyanin has been identified to possess antioxidant properties.
Researchers at Oregon State University have produced blue tomatoes using conventional breeding techniques, cross-pollinating domestic tomatoes with wild varieties that exhibit the "Anthocyanin fruit" (Aft) gene. As of the 2012 growing season, Oregon State University developed blue tomato seeds became commercially available under the name "Indigo Rose Tomato." The blue color is produced on the outside of the tomato where the fruit is exposed to direct sunlight. The shaded side of the fruit is green when unripe, red when ripe, and the inside is red or deep pink. The tomatoes are small, about 2 inches across, round, and grow in clusters of 6 to 8. Flavor is described as slightly acidic. The vines are said to be indeterminate but compact, and disease resistant.
Blue tomatoes have also been developed at the John Innes Centre in the UK using GMO gene splicing techniques, incorporating genes from snapdragons to increase the anthocyanin levels. The colour is in the skin and the flesh of the tomato.
Israeli scientists have also bred an anthocyanin coloured tomato using conventional breeding techniques, called Black Galaxy.
- "OSU RESEARCHERS ADD POTENTIAL HEALTH BENEFITS TO TOMATOES" (Press release). Oregon State University. 19 February 2004.
- Butelli E, Titta L, Giorgio M, et al. (November 2008). "Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors". Nature Biotechnology 26 (11): 1301–8. doi:10.1038/nbt.1506. PMID 18953354.
- Purple tomato 'may boost health', Health, BBC News online, 26 October 2008
- Purple as a tomato: towards high anthocyanin tomatoes