Vallone remembers her mother and grandmother squeezing melons and holding them up to their noses, searching for the tell-tale scent that says, “Now.” 

This is one reason she is using an experimental device called the “artificial nose.” It’s actually named the “zNose” and made by the company, Electronic Sensor Technology.

In Vallone’s research — she’s concentrating on melons — that means getting information about volatile compounds that create an aroma. To analyze aromas from fruit, the research team, which includes scientists from the USDA, UC Davis Department of Food Science and Technology, and the University of Florida Citrus Research and Education Center, combined ultra-fast gas chromatography with a state-of-the-art surface acoustic wave sensor that dramatically speeds up the testing process.

Vallone and others in the team recently published their research, “Fruit Volatile Analysis Using an Electronic Nose,”in the Journal of Visualized Experiments.

Their work is part of a multi-state project funded by the U.S. Department of Agriculture and several companies, including Harris Moran, a California-based subsidiary of a multinational agricultural cooperative run by French farmers. Their goal is to identify varieties of produce with longer shelf lives and more flavor. 

Vallone, who first came to UC Davis as a visiting Ph.D. student from the University of Naples, is working with professor Florence Zakharov in the Plant Sciences Department and Susan Ebeler in the Viticulture and Enology Department.

“It’s a big improvement,” said Vallone about using the artificial nose. “It’s not only faster, but much cheaper and requires less training. It’s also portable. One of the things we were thinking is that people could bring it into the field to detect ripeness at harvest time.”

Vallone and other members of the lab are still analyzing the results from testing the technology in the field last summer. The artificial nose still detects fewer compounds than traditional gas chromatography, so more work might be needed before it can be used commercially.  

With more than 100 compounds combining to produce the sweet, evocative scents of melons in the summer, Vallone admits that technology hasn’t quite caught up with nature — or with her grandmother.