Professor
Invents 'Ripeness' Sticker
Associated
Press
TUCSON, Ariz. (AP) --A University
of Arizona professor has invented a sticker that
can tell consumers if a fruit or vegetable is
ripe. The stickers will be available to growers
next year and should make their way to supermarkets
within two to three years, said Mark Riley, a
UA assistant professor of agricultural and biosystems
engineering.
He said growers and grocers throw out thousands
of bushels of fruit each year 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.
"Right now, picking fruit is more of an art
than it is a science,'' Riley said.
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, Riley said.
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, Riley said.
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.
There is a patent pending for the stickers through
the UA. Riley said when RediRipe goes to market,
the university will keep the patent and the company
will license the product.
Research on ethylene's use in fruit ripening began
in the 1940s, and the gas is used to ripen fruits
and vegetables in storage.
Riley has done multiple small field tests on his
stickers --including at an apple orchard in Willcox
--and plans a much larger field test this fall
in Washington.