Carrots of all colours in store wars

The humble carrot has been revamped and is about to become the main weapon in a battle of the supermarkets.

Today, Sainsbury launches a purple version, just as Waitrose's yellow carrot hits the shelves - and all achieved without a single genetic engineer or pack of colouring.

Purple and yellow carrots are merely different varieties of the more familiar orange type, and they offer all the same health benefits , such as helping night vision and promoting healthy skin.

The purple type may even protect against heart disease and various forms of cancer, according to Dutch scientists. It appears this is down to pigments called anthocyanins which act as antioxidants.

The stores are introducing the new varieties in a bid to make vegetables more exciting to children, thus encouraging parents to buy them and the youngsters to eat healthily. The yellow carrot, an organic variety from Austria, is also slightly sweeter than the orange type.

The Fresh Produce Consortium also hopes a new generation will be drawn to carrots. "We are supportive of anything which generates interest and encourages children to eat fresh fruit and vegetables," a spokesman said.

While the new lines are radical to modern eyes, Egyptian temple drawings from around 2000BC depict a plant believed to be a purple carrot. In Roman times, too, carrots were purple and sometimes white.

These colours were imported into Europe in the 14th century and the carrot only became orange after patriotic Dutch farmers in the 16th century developed its new shade.

The struggle to make children eat their fruit and vegetables has seen the recent creation of square watermelons and green tomato ketchup.

Sainsbury's root buyer Russell Crowe said: "We are very excited to sell the purple carrot exclusively. Hopefully this unusual colour will influence children to eat more vegetables while parents can rest assured there is nothing artificial about the carrots."

But there is a price to pay. The Waitrose yellow carrots cost £1.49 a kilo while Sainsbury's purple ones are £1.19 for 500 grams.