By Sharon Omahen


University of Georgia

University of Georgia researchers have developed a solution that
could help prolong the shelf life of fresh peaches.

Peach growers have to pick peaches earlier than ideal so they
don’t perish en route from the orchards to retail stores.

“Growers pick peaches when they reach what’s called the ‘market
mature’ stage,” said Stan Prussia, an engineer in the biological
and agricultural engineering department with the UGA College of
Agricultural and Environmental Sciences.

Surviving shipping

“They have to be sure their product can survive shipping,” he
said, “because when a shipment reaches its destination, a sample
is pulled and if the peaches are too soft, the whole load can be
rejected.”

Working with visiting scientist Grzegorz Lysiak of the
Agricultural University in Poznan, Poland, Prussia and UGA
agricultural economist Wojciech Florkowski applied a method
currently used on apples.

“We dipped half a batch of peaches in a 1-percent calcium
chloride solution for half an hour. The other half we left
untouched,” Prussia said.

He says the solution is similar to what is used for adding
chlorine to swimming pools. “Table salt is sodium chloride, and
this is calcium chloride,” he said.

The test peaches were then put through storage and shipping
conditions.

Test peaches stayed firmer longer

“Peaches normally don’t stay in storage for more than two weeks.
But we kept our test peaches in storage longer,” Prussia said.
“After 21 days of storage, we saw a definite difference as the
treated peaches remained firmer.”

Adding the salt solution wouldn’t be hard for growers. They
normally have hydrocoolers in their packing houses to cool the
peaches with water, Prussia said.

“However, we would need to make sure the salt solution does not
harm the hydrocooling equipment over time,” he said.

Another glitch the researchers are working out is the slight
aftertaste the solution leaves behind. Using a taste panel, the
scientists found that it “slightly changes” the taste of the
peaches.

Working to remove aftertaste

“It was a slight change,” Prussia said. “But it was enough of a
change that our taste panel detected it.” The research team is
now working to modify the salt solution.

“We have to do more research to see if we can lower the
concentration of the solution so the taste isn’t affected and
(growers) still get the benefits,” he said.

The scientists are also looking into an alternative to dipping
the peaches in the packing houses.

“We’d like to try spraying the peach trees while they’re growing,
either once a week or once every two weeks,” Prussia said. “This
way the calcium would get into the peaches as they grow.”

He says this method is used now on other crops with no aftertaste
effects.

A postharvest specialist, Prussia says peaches could be allowed
to ripen longer on the trees if they weren’t too soft to ship.
Staying longer on the trees would make peaches sweeter.

Prussia hopes spraying the salt solution onto the peach trees
will be the answer to this dilemma.

“It would be great if the peaches could be left on the trees
longer to develop full flavor, still ship well and arrive tasting
better for consumers,” he said.

The researchers are now sharing their findings with the Georgia
Agricultural Commission for Peaches, which partially funded the
first stage of the project.