Study Identifies Geographic Origins of Hazelnuts

Hazelnuts have been consumed by humans since the Mesolithic era, and today, they're the third most commonly grown nut, after almonds and walnuts. Italian hazelnuts fetch the highest price, followed by those from Turkey, the U.S., Georgia, and Azerbaijan. Consumers today are willing to pay more for better nuts, and testing methods are needed to reliably authenticate the nuts' country of origin.

Previous studies evaluated analytical techniques for chemically profiling hazelnuts, but they focused either on a small region or on particular hazelnut varieties. Thomas Hackl and colleagues at the University of Hamburg wanted to find a method that could pinpoint geographic origin regardless of variety.

The research team ground up 262 nut samples from different regions around the world and extracted the metabolites, which they identified with proton NMR spectroscopy. The spectra showed that nuts from different regions had different metabolite profiles, with certain compounds proving distinctive for specific areas. For example, the amount of betaine, an amino acid derivative, varied significantly in nuts from different countries. Thus, betaine could potentially be a good biomarker in a future test to identify the source of a particular batch of nuts, the researchers say. The team's new NMR method with an accuracy of 96 percent provides a more accurate determination and could be used in combination with a previously devised test that assessed a different group of hazelnut metabolites using liquid chromatography and mass spectrometry.

For more details, read the news release from the American Chemical Society.