Foods like blueberries, blackberries, plums and red cabbage contain purple pigments called anthocyanins. These pigments are antioxidants and are believed to reduce cancer risk, decrease inflammation and help prevent cardiovascular disease. Researchers from Britain have used genetic engineering techniques to create purple tomatoes that make anthocyanins.
The new tomatoes are reportedly identical to red varieties apart from their color. The researchers say that they wanted to create purple tomatoes becauses tomatoes are more widely eaten than other foods containing anthocyanins. They hope to improve the nutritional content of all tomato-based foods, including pizza sauce and tomato juice.
The purple tomatoes actually look maroon or a very dark purple in photos that I've seen. They were created by adding a gene from a snapdragon plant to tomato plants. Genetic engineering is sometimes a controversial topic and can provoke strong feelings on both sides of the argument. It can have important benefits, however, such as the production of insulin by bacteria for diabetics, and it's becoming more common as the technology improves.
The harvested tomatoes have been turned into juice and their seeds have been burned to prevent contamination of the environment. Although the research was run by British scientists, the tomatoes were grown and harvested in a Canadian greenhouse, reportedly because the country is "more supportive" of genetic engineering experiments than Britain. The juice will be tested on humans to see if it has health benefits.