Purple tomatoes soon to be sold in shops

Genetically modified tomatoes with added nutritional value could soon find their way in to supermarkets.

Despite a general lack of consumer interest in any food that has been genetically modified, the new purple-hued tomatoes are being touted as an improvement over traditional red tomatoes due to the addition of anthocyanin, an antioxidant with cancer-fighting properties.

"With these purple tomatoes you can get the same compounds that are present in blueberries and cranberries that give them their health benefits - but you can apply them to foods that people actually eat in significant amounts and are reasonably affordable," said Professor Cathie Martin.

The new tomatoes are being mass-produced in Canada for sale in Britain and elsewhere in the form of fruit juice. The modification process, which involves the transfer of a gene from a snapdragon plant, triggers a process that causes anthocyanin to develop.

Scientists are hoping that the same technique can be used to add nutritional value to other tomato-containing foods such as ketchup and pasta sauce.