Disease-beating tomatoes may soon be on menu

Pizza that fights heart disease and cancer may not be far away thanks to a new genetically modified ‘‘healthy’’ tomato.

Scientists used a gene from the Petunia plant to beef up the level of chemicals called flavonols in tomato peel.

Flavonols are powerful antioxidants which mop up free radicals - destructive molecules that damage cells and DNA, and hasten ageing.

Research has shown that certain foods, such as onions and tea, are rich in these substances.

Tomatoes also have the compounds in their skin, but the natural levels are much lower. They are most digestible in cooked and processed tomatoes, hence the potential health benefits of pizza made with the GM fruit.

The British and Dutch scientists found that flavonol synthesis in the tomato is governed by an enzyme called chalcone isomerase.

By inserting a Petunia gene that encodes for the enzyme into the tomato, fruits were engineered with skin containing as much flavonol as onions - an up to 78-fold increase.

The Petunia is a plant with high levels of flavonols in its reproductive structures.

Taste was not affected, and 65% of the flavonols were retained when the GM tomatoes were processed into paste.

The scientists led by Martine Verhoeyen, from Unilever Research at Sharnbrook, Bedfordshire, said the research could lead to ‘‘functional’’ tomato-based food products such as pizza.

One type of flavonol, quercetin glycoside, was ‘‘significantly increased’’ in the peel of the modified tomatoes. Smaller but still substantial increases in another flavonol called kaempferol glysoside were also seen.

The scientists, who reported their findings in the journal Nature Biotechnology, wrote: ‘‘These new varieties may offer opportunities for tomato-based products with an expanded range of potential health benefit properties.’’