NOTHING is better on a hot day than biting into an ice-cold slice of watermelon.

But scientists now say the juicy summer fruit is most nutritious when stored and served at room temperature, because levels of beta carotene are double and levels of the carotenoid lypocene are 20 percent higher, according to a study by the USDA Agricultural Research Service in Lane, Oklahoma.

The study is in the latest issue of Journal of Agriculture and Food Chemistry.

This new finding has surprised many who thought refrigeration would conserve essential nutrients.

Penelope Perins-Veazie and Julie Colling stored uncut, fully ripe melons at 20 degrees Celsius overnight. The next morning the melons were cut up and sampled for color, condition and carotenoid levels. They also stored various samples of different types of melons for two weeks at 21, 13 and 5 degrees Celsius.

The researchers found that melons stored at room temperature experienced an increase in carotenoid levels of 11 to 40 percent. Those stored at low temperatures saw much lower or no increase in carotenoid levels.

The researchers stressed that the benefits of room-temperature storage apply only to uncut watermelons. Cut melons should be refrigerated.

The researchers stressed that the benefits of room-temperature storage apply only to uncut watermelons. Cut melons should be refrigerated.

Cooling the melon in the refrigerator before eating it does not reverse the nutritional advantages of room-temperature storage, it only slows it down or stops it.

Editor: Donald