Researchers claim that Genetically Modified tomato varieties
are more flavourful and have better
health and shelf life characteristics because even higher levels of the
compounds can be achieved.
"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," said Professor Cathie Martin
from the John Innes Centre.
How the research was
In research to be published in Current Biology, Martin and colleagues studied tomatoes enriched in
anthocyanin, a natural pigment that confers high antioxidant capacity. The
purple GM tomatoes have already been found to prolong the lives of cancer-prone
mice and in the latest findings they also more double the normal shelf life of
tomatoes from an average of 21 days to 48 days.
"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," said Yang Zhang, lead
author from the John Innes Centre.
One way to improve shelf life is to pick tomatoes early when
they are still green and induce them to ripen artificially with ethylene.
However, this results in loss of flavour. Another method is to grow varieties
that never fully ripen, but these also never develop a full flavour.
In the current study, 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 purple tomatoes were also
less susceptible to one of the most important postharvest diseases, grey mould
caused by Botrytis cinerea.
used as ‘parents’
Conventional tomatoes can now be screened for their
antioxidant capacity. Those found to be highest in antioxidant compounds can be
used as parental lines for breeding.
"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,"
The findings could also be applied to other soft fruit such
as strawberries and raspberries.
Other varieties of JIC tomatoes high in a variety of
compounds such as those found in red wine are being used by Essex company
Biodeb to develop a range of skincare products.