New research on GM tomatoes with double the shelf life
And the natural pigment slows down the over-ripening process that leads to rotting and softening - creating a better taste. Previous studies on purple GM tomatoes have shown those enriched in anthocyanin prolongs the life of cancer-prone mice.
The John Innes Centre, Norwich, researchers say one way to improve shelf life is to pick tomatoes early when they are still green and induce them to ripen artificially with ethylene, but that results in a loss of flavour.
Another method is to grow varieties that never fully ripen, but these also never develop a full flavour.
In the study for journal Current Biology, anthocyanins were found to slow down the over-ripening process that leads to rotting and softening - achieving a tomato with a long shelf life and full flavour.
The researchers also found the purple tomatoes were also less susceptible to one of the most important post-harvest diseases - grey mould caused by Botrytis cinerea.
They say conventional tomatoes can now be screened for their antioxidant capacity, with those found to be highest in antioxidant compounds used as parental lines for breeding.
The findings could also be applied to other soft fruit - such as strawberries and raspberries - and other varieties of tomatoes high in a variety of compounds are already being used by Essex company Biodeb to develop a range of skincare products.
Professor Cathie Martin said: "Working with GM tomatoes that are different to normal fruit only by the addition of a specific compound, allows us to pinpoint exactly how to breed in valuable traits.
"Our research has identified a new target for breeders to produce tomato varieties that are fuller in flavour, and so more appealing to consumers, and more valuable commercially due to increased shelf life."
Lead author Yang Zhang said: "Post-harvest losses due to rotting are such a serious problem for growers and supermarkets that even an increased shelf life of one day would make an enormous difference to them."
Source: dailymail.co.uk