Even Gourmet Sweet Vidalias Can Drive Georgia Onion-Lab Specialists to Tears

Janie Hayes wears a mask and goggles at work. Otherwise, her job would drive her to tears.

The lab technician at the University of Georgia’s Coastal Plain Experiment Station peels and grinds samples of Vidalia onions and then conducts chemical tests that may someday enable consumers to identify the strength of an onion.

The gourmet onions have a reputation of being the sweetest, mildest in the world, but when there are 50 to 60 Vidalias to slice in a day, her lab fills with eye-burning fumes and a pungent odor.

“I have to wear a mask and goggles,” Hayes said. “Otherwise, my eyes burn and my sinuses throb.”

She and horticulturist Doyle Smittle are collecting information on sugar and pungency levels in Vidalias.

“We’re trying to develop a rapid, objective method of measuring quality in onions,” said Smittle. “We’d like to have a technique . . . simple enough that a grower or group of growers could measure the quality in at least every field of onions they have.”

This summer, food scientist Robert Shewfelt will convene a taste panel at the Experiment Station in Griffin to sample some of the same onions that have been tested.

Seeking Guidelines

Smittle, who has been studying the compounds in onions since the mid-1970s, hopes to establish a relationship between the chemical composition of Vidalias and the onions preferred by the taste panel.

Onions have virtually no odor until their tissue is damaged by slicing. At that point, an enzyme triggers a chemical reaction that produces ammonia and other substances that cause tears.

Chemical tests give a good indication of an onion’s pungency, but they’re too complicated and costly for routine use by growers, said Smittle.

Taste buds aren’t as reliable as laboratory tests because humans tend to forget how bad or good a sample was, he said. Members of the taste panel will sample six onions a day, then they’ll come back a week or two later and evaluate the same onions.

The horticulturist foresees use of an infrared device that would scan onions in the packing sheds and determine their mildness. Since sugars absorb infrared light, there may be a correlation between taste and the amount of light that passes through onions, he said.

Mildness Varies

Smittle believes growers eventually will be able to place stickers on each onion, with a picture of a thermometer showing the degree of mildness. His tests have shown that onion mildness varies from field to field and season to season.

With a pungency rating, consumers could use the hotter onions in dishes that require more flavor. The rating also would help consumers adjust the thickness of slices to specific needs.

Georgia’s 260 registered growers and packers have turned the Vidalia onion into a $30-million-a-year crop. Protected by state law, onions bearing the Vidalia label have to be a yellow Granex hybrid. The growing region encompasses 13 counties in southeastern Georgia and parts of six others.

Growers claim Vidalias are sweetest because of the variety and the low-sulfur soil around Vidalia, a town of 10,000 residents about 80 miles west of Savannah.