A sweet Spanish orange that contains the health-giving red pigments of the Sicilian blood orange has been created by scientists who believe the fruit will produce a "superjuice" that helps to combat a range of medical disorders, from obesity and heart disease to irritable bowel syndrome.
The first genetically modified (GM) Valencia orange seedlings with added genes for the red pigments of the Sicilian blood orange are now growing in a Spanish research centre. They should produce the first GM oranges later this year, according to researchers at the John Innes Centre in Norwich, who led the study.
Blood oranges are rich in anthocyanins – pigments that impart red, purple and blue colours to fruit – which are also believed to protect the body against a wide range of illnesses, said Professor Cathie Martin of the John Innes Centre.
"Studies have shown that blood orange juice can prevent weight gain, and other studies, yet to be published, have shown that even one drink of blood orange juice can improve your cardiovascular risk factors compared to blonde orange juice," Professor Martin said.
However, blood oranges are notoriously difficult to cultivate because they require periods of cold temperatures immediately prior to harvesting, which stimulates the production of the anthocyanins, Professor Martin said.
For this reason, the cultivation of blood oranges is largely confined to one of the slopes of Mount Etna in Sicily, but by transferring the genetic switch for the red pigment genes to the commercial Valencia orange, the scientists hope to extend production of blood-red oranges to Spain and Brazil.
"It's sometimes very difficult to find blood orange juice and the reason for that is that you need special climatic conditions for them to grow. They need a period of cold during times of harvest," Professor Martin said.
In one unpublished experiment involving 25 volunteers who ate a full English breakfast, those who drank half a litre of blood orange juice with their meal had significantly lower risk factors for heart disease, such as fatty acids, in the bloodstream.