When is a Vidalia onion not a Vidalia onion? University of
Georgia researchers are searching for a definitive answer.

George Boyhan, an Extension Service horticulturist with the
UGA College of Agricultural and Environmental Sciences, is
wrapping
up a three-year study on Vidalia onions. He and other scientists
hope to help farmers grow the sweetest product and make sure
shoppers
get a mild, quality onion.

Searching Through the Varieties

“We started with a list of 12 varieties of Vidalia onions
that were recommended as Vidalias by the Georgia Department of
Agriculture,” Boyhan said. “We planted field plots of
these varieties and gathered data on their
characteristics.”

Boyhan said Vidalias have to be a certain yellow-skinned,
overwintering
type with the same shape as the original Granex 33 variety. But
most of all, they have to have the right mild flavor.

At her lab at the Georgia Experiment Station in Griffin, Ga.,
UGA food scientist Anna Resurreccion coordinates this part of
the study.

“For the taste tests, we use a panel of nine people, some
of whom have been trained since 1984,” Resurreccion said.
“Each has had many hours of training … in rating the
flavor
and texture properties of food.”

Trained to Taste

The panelists are screened on whether they can detect a food’s
sweet, sour, salty and bitter tastes and other attributes, she
said.

“They also have to be able to identify a number of
commonly
found food flavors, including pineapple, banana, vanilla, orange,
lemon and licorice,” she said. “Then we train them to
give a number for the intensity of each flavor.”

Resurreccion knows the training is complete when a panelist
gives identical ratings each time he evaluates the same sample
and when his ratings are consistent with other panel members’
ratings.

“Training panelists is a lot like calibrating a
machine,”
she said.

The panelists come from all walks of life. But only one in
about 50 people Resurreccion screens will meet all the criteria
to become a panelist.

Breaking Down the Tastes

For the onion taste tests, the panel uses salsa as a
comparison
for a hot food item and horseradish as a pungent food.

“We break down the different tastes in an onion,”
said Paula Scott, a security guard who has been a panelist for
14 years. “We know the amount of heat in the salsa and the
pungency of the horseradish, so we determine where the onion
fits.
It may have 80 percent of the heat of salsa and 20 percent of
the pungency of horseradish.”

The
panel also finds whether the onions have a sulfur or a
green-apple
flavor. For each test, the panel rates a representative sample
from 10 onions.

“Some onions out there are being called Vidalias that
don’t qualify as far as taste goes,” said Karen Shockley,
a homemaker on the panel. “Even some that are grown in the
right region still have a pungent, hot taste and a sulfur flavor.
We’re searching for a way to assure consumers that Vidalias will
taste like Vidalias — mild and sweet.”

UGA horticulturist Bill Randle is analyzing the onions’
pyruvic
acid content. Georgia Southern University chemist Norman Schmidt
is also working on the Vidalia onion’s flavor chemistry.

“We want to correlate our results with theirs and
possibly
develop a chemical test for determining Vidalia onion
quality,”
Resurreccion said.

“The goal is to be able to scientifically determine when
an onion should be called a Vidalia onion and when it
shouldn’t,”
she said. “Right now there is no chemical instrument that
can evaluate all of these flavors simultaneously. We have to rely
on people like our trained panelists.”

The study is funded by the Vidalia Onion Committee, the grower
oversight committee for the federal marketing order. Boyhan hopes
to have it completed and a recommendation ready for growers by
the end of June.