Often referred to as the diamonds of the culinary world, truffles are prized for their pungent flavour and aroma and can fetch hundreds of dollars per pound. In 2007, a 3.3 lb Italian white truffle sold for a record $330,000 at auction.
Now a group of Université Laval chemists is hoping to elevate the profile of a Québec-grown species. The Appalachian truffle (Tuber canaliculatum) grows in wooded areas of Eastern North America and the researchers focused their attention on those from the province’s Eastern Townships.
Using headspace solid-phase microextraction and gas chromatography-mass spectrometry, they analysed the truffle’s “volatilome,” finding that it’s composed of more than 30 volatile chemicals, six of which are unique to this species.
Truffles are subterranean fungi of the Tuber species that grow on the roots of various trees in association with soil microorganisms and require several years to mature. Old-world species from France, Italy and Spain are among the most prized.
“Microorganisms in Québec are different than in France so we thought it must be unique in terms of aroma,” says chemist Normand Voyer. “It’s one thing to say it and smell it, but it’s another to prove it scientifically.”
Working with samples collected from Québec truffle producer, ArborInnov, Voyer, his master’s student David Fortier and his research professional Jean-Christophe Séguin confirmed the Appalachian truffle does in fact have its own aromatic profile.
Fortier – a long-time mushroom enthusiast – says while other truffles have been well-studied, up until his team published its findings in August in the journal ACS OMEGA, little was known about the Appalachian truffle.
The aromatic profile for the same species of truffle can be extremely variable depending on where it is grown. Its host tree, soil composition, and maturity all influence the volatile chemicals it produces.
A prime example is the white truffle Tuber magnatum in Italy. “When harvested specifically from Piedmont it’s significantly more expensive as its aroma is richer than when picked 350 kilometres further east in Emilia-Romagna,” says Fortier. This means the volatilomes of Appalachian truffles in different locations in North America are likely variable.
Not surprisingly perhaps, the Laval researchers’ two greatest challenges had nothing to do with isolating the Québec sample’s distinct aromatic profile. The first challenge was ensuring Tofu, the Jack Russell Terrier ArborInnov founder Jérôme Quirion uses to sniff out truffles, didn’t gobble up the fungus. “Thankfully, Jérôme knows exactly when to pull him out,” says Voyer.
The second challenge was getting the truffles back to Voyer’s lab and analysing them before their signature odor and taste began to degrade. Estimates for how long that takes range from 24 hours to about a week. The chemists were able to get the job done within a day.
For his part, Quirion says he’s very pleased with the demonstration of his truffles’ uniqueness. “Québec truffles have the potential to distinguish Québec gastronomy on a global level,” he said in a news release.
That in fact is Fortier’s next task. This fall, he will travel to France, where he will analyse volatile chemicals from French samples and samples couriered overnight from Québec. Fortier will also enlist a human smell tester known as a “professional nose” to characterise each volatile chemical separately.
“I was struck by a great passion for wild mushrooms about ten years ago,” he says. “This passion has continued to grow and now, studying the aroma of truffles is by far the most stimulating project I could imagine for my graduate studies.”