Life> no use

New sticker lets you know when fruit is ripe

(Arizona Daily Star)
Updated: 2006-08-07 09:56

A University of Arizona professor has invented a sticker that can tell consumers if a fruit or vegetable is ripe. 

Each year growers and grocers throw out thousands of bushels of fruit because it ripened faster than it could get to market or be sold.

With no simple way to tell whether fruit that looks good on the outside will taste good on the inside, consumers often buy peaches, pears and melons they can't eat because they're under-ripe or overripe.

With the special sticker, picking fruit is more of an art than it is a science.

A marker on Riley's RediRipe stickers detects a chemical called ethylene gas, which is released by fruit or vegetables as they ripen.

As that happens, the sticker turns from white to blue.

The more ethylene gas the fruit produces, the darker the blue.

The color shift is not instantaneous once a sticker is attached. It takes about 24 to 48 hours, depending on how fast the fruit is ripening.

And there are still bugs to be worked out: The stickers do not change color to reflect an overripe or rotten piece of fruit. Also, not all fruit produces enough ethylene to be detected by the sticker, said Jim McFerson, manager of the Washington Tree Fruit Research Commission, a growers' research group that helped sponsor the research.

"There is still a lot of research to do," McFerson said.

Each sticker is expected to cost growers and grocers about a penny, Riley said.

Research on ethylene's use in fruit ripening began in the 1940s, and the gas is used to ripen fruits and vegetables in storage.