Cold watermelon less nutritious

WASHINGTON -- That ice-cold watermelon may be refreshing, but it can be less nutritious than watermelon served at room temperature, US Department of Agriculture scientists reported last week.

Watermelons stored at room temperature deliver more nutrients than refrigerated or freshly picked melons, they reported in the Journal of Agricultural and Food Chemistry.

Penelope Perkins-Veazie and Julie Collins of the USDA's South Central Agricultural Research Laboratory in Lane, Okla., looked specifically at carotenoids -- antioxidants that can counter the damage caused by sun, chemicals, and day-to-day living.

Watermelon is rich in lycopene, an antioxidant that makes watermelons and tomatoes red and may help prevent heart disease and some cancers.

Perkins-Veazie and Collins tested several popular varieties of watermelon stored for 14 days at 70, 55, and 41 degrees Fahrenheit.

Whole watermelons stored at 70 degrees had substantially more nutrients, they reported.

Compared with freshly picked fruit, watermelon stored at 70 degrees gained up to 40 percent more lycopene and 50 percent to 139 percent extra beta-carotene, which the body converts to vitamin A.

``All watermelons used in our study had been selected by commercial growers as fully ripe when harvested," the researchers wrote.

They said their findings showed watermelons continue to produce these nutrients after they are picked, and that chilling slows this process.

``The usual shelf life for watermelons is 14 to 21 days at 55 F after harvest," the researchers wrote. At refrigerated temperatures, like 41 degrees, watermelon starts to decay and develop lesions after a week.