Have you ever wondered why a tomato picked fresh from the vine tastes so much better than its supermarket equivalent.
A group of scientists in the United States has discovered why — and they also claim to have found an ingenious and simple way to keep that tastiness.
Dunking ripe tomatoes in hot water for five minutes before they are stored in a cool place for transport to retailers locks in flavour that is otherwise lost, the scientists said.
British tomato farmers argue that the subtropical fruit should never be kept in the fridge but tomatoes from all over Europe are shipped to the UK in refrigerated lorries to delay ripening before they go on sale.
Jinhe Bai, a chemist at the US Department of Agriculture who led the study, found that the chilling process was to blame for tomatoes tasting bland.
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He placed green Florida-grown tomatoes in water heated to 51.6C for five minutes, before cooling them to room temperature and then chilling them to the level that is used for shipping.
“Heating and then chilling increases the tomato’s resistance to the internal chilling injury that is causing the loss of the aroma compounds,” Dr Bai said.
In the tests the pre-heated tomatoes had more flavour and smelt as if they had just been picked. Of 21 volunteers, 14 said that the heated tomatoes had “a greater tomato aroma”.
Dr Bai said: “There’s no negative effect from the hot water treatment and it will help to kill fungi or bacteria on the fruit that cause postharvest diseases, and it should be an easy practice to adopt.”
Dr Bai is working with tomato packers to make sure that they know the technique.
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Chris Joy, the owner of Ringwould Nurseries in Kent, which supplies tomatoes to London markets, said that tomatoes should not be put in the fridge until they were fully ripe.
“Flavour in a tomato comes from the sugar content and to gain the most sugar content it has to ripen naturally. Once it’s really red you can keep it in the fridge for weeks because it is as ripe as it’s going to get and the flavour will already be there,” he said.
British tomatoes from farmers’ markets or small producers are unlikely to have been refrigerated because they will have been picked only a few days before, he said.
To replicate Dr Bai’s test the water in which the tomatoes are heated must be about 50C.
A word of warning, however: tomatoes are the fourth most common trigger of gout, according to a study of more than 2,000 people by Otago University in Dunedin, New Zealand.