The group, led by food scientist Rob Shewfelt, is studying how to measure pungency, or the chemical reaction that makes you cry or leaves a hot feeling in your mouth.
They are in the final year of a four-year study comparing instruments that measure sweetness and pungency with trained sensory panelists and untreated onion tasters.
In the past, researchers used a method where fresh onions were crushed and the pyruvic acid and enzymes were measured by instruments.
The test proved effective but destroyed the onion in the process.
Food scientist Chi Thai is exploring non-destructive methods, such as infrared scanning, to measure these factors.
In addition, Norman Schmidt of Kansas' Tabor College is using a gas chromatograph to measure factors that make people's eyes tear up. That data will be related to results from the trained sensory panelists.
The trials have involved four Vidalia onion varieties with varying degrees of sweetness and pungency.
The researchers found a positive relationship between the instruments and the trained panelists.
They also found that an absence of pungency compounds resulted in higher consumer acceptance.