When is a Vidalia onion not a Vidalia onion? University ofGeorgia researchers are searching for a definitive answer.George Boyhan, an Extension Service horticulturist with theUGA College of Agricultural and Environmental Sciences, is wrappingup a three-year study on Vidalia onions. He and other scientistshope to help farmers grow the sweetest product and make sure shoppersget a mild, quality onion.Searching Through the Varieties”We started with a list of 12 varieties of Vidalia onionsthat were recommended as Vidalias by the Georgia Department ofAgriculture,” Boyhan said. “We planted field plots ofthese varieties and gathered data on their characteristics.”Boyhan said Vidalias have to be a certain yellow-skinned, overwinteringtype with the same shape as the original Granex 33 variety. Butmost 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 ofthe study.”For the taste tests, we use a panel of nine people, someof whom have been trained since 1984,” Resurreccion said.”Each has had many hours of training … in rating the flavorand texture properties of food.”Trained to TasteThe panelists are screened on whether they can detect a food’ssweet, sour, salty and bitter tastes and other attributes, shesaid.”They also have to be able to identify a number of commonlyfound food flavors, including pineapple, banana, vanilla, orange,lemon and licorice,” she said. “Then we train them togive a number for the intensity of each flavor.”Resurreccion knows the training is complete when a panelistgives identical ratings each time he evaluates the same sampleand 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 inabout 50 people Resurreccion screens will meet all the criteriato become a panelist.Breaking Down the TastesFor the onion taste tests, the panel uses salsa as a comparisonfor 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 for14 years. “We know the amount of heat in the salsa and thepungency of the horseradish, so we determine where the onion fits.It may have 80 percent of the heat of salsa and 20 percent ofthe pungency of horseradish.”Thepanel also finds whether the onions have a sulfur or a green-appleflavor. For each test, the panel rates a representative samplefrom 10 onions.”Some onions out there are being called Vidalias thatdon’t qualify as far as taste goes,” said Karen Shockley,a homemaker on the panel. “Even some that are grown in theright region still have a pungent, hot taste and a sulfur flavor.We’re searching for a way to assure consumers that Vidalias willtaste like Vidalias — mild and sweet.”UGA horticulturist Bill Randle is analyzing the onions’ pyruvicacid content. Georgia Southern University chemist Norman Schmidtis also working on the Vidalia onion’s flavor chemistry.”We want to correlate our results with theirs and possiblydevelop a chemical test for determining Vidalia onion quality,”Resurreccion said.”The goal is to be able to scientifically determine whenan onion should be called a Vidalia onion and when it shouldn’t,”she said. “Right now there is no chemical instrument thatcan evaluate all of these flavors simultaneously. We have to relyon people like our trained panelists.”The study is funded by the Vidalia Onion Committee, the groweroversight committee for the federal marketing order. Boyhan hopesto have it completed and a recommendation ready for growers bythe end of June. read more