Bramleys's tomatoes are so red because they contain twice as much lycopene, the pigment that makes tomatoes red, as normal. "Normal tomatoes usually have paler portions inside, but these ones have even, red pigmentation throughout,"he say.
They also contain abnormally high levels of beta-carotene, the compound that makes carrots bright orange. Both are carotenoids, a group of compounds found widely in fruit and vegetables, "If we can establish that higher levels of carotenoids in the diet are beneficial, we are developing technology to modify common fruit and vegetables so that they produce more," he says.
Bramley produced the extra lycopene and beta-carotene by inserting a gene into tomatoes that makes phytoene synthase, the comp in plants that triggers the synthesis of many carotenoids.
Bramley and his colleagues have just begun to evaluate some 30 other types of carotenoid.