The spring truffle and the Piedmont truffle are difficult to distinguish from the outside. However, one mushroom is easy to grow and therefore inexpensive, while the other is exquisite and comparatively expensive. Fraudsters therefore like to sell the spring truffle under a false name. But a newly developed analysis technology could now thwart their plans. Food chemists have identified two aromatic substances that can be used to clearly tell the two white truffles apart.
Truffles are considered a luxury food. Some truffle species are particularly expensive and are therefore often the target of food fraud. For example, high-priced Piedmont truffles (Tuber magnatum), which currently cost up to $3,000 per specimen, are difficult to distinguish based on their appearance from the cheaper spring truffles (Tuber borchii), which cost only about a tenth. Both varieties are white truffles, which, unlike black truffles, have an intense aroma and are not cooked.
However, the spring truffle mushroom is widespread in Europe and can easily be grown in plantations, while the Piedmont truffle has so far been difficult to cultivate and has an overall smaller distribution area. “Therefore, there is of course a great incentive to market cheap and easily available spring truffles as Piedmont truffles,” says Philipp Schlumpberger from the Leibniz Institute for Food Systems Biology at the Technical University of Munich.
Characteristic aromas
Together with two of his colleagues, Schlumpberger has now developed a new analysis method with which the fruiting bodies of the two types of fungi can be clearly distinguished and fraud can be prevented. To do this, the researchers analyzed and compared the ingredients of the truffles, including their volatile aromas, using an automated screening process. Optimized forms of gas chromatography and mass spectrometry were used. From thousands of molecules, the food chemists identified two characteristic compounds in the tubers that allow the two varieties to be objectively differentiated: furan-2(5H)-one and bis(methylsulfanyl)methane, also known as truffle sulfide.
In the 17 samples of Piedmont truffles examined, the scientists found without exception higher concentrations of bis(methylsulfanyl)methane compared to the six samples of spring truffles. In contrast, the furan-2(5H)-one concentration was significantly higher in all spring truffle samples than in the Piedmont truffles.
Technology can be used in routine analyses
Based on the amount of these aromatic substances, the two white truffles can be clearly distinguished. “In summary, our data show that quantification of the two marker compounds is a suitable analytical approach to objectively distinguish between the two truffle species,” says co-author Martin Steinhaus. According to the food chemists, the newly developed method can be used directly in routine analysis. The equipment required for this is widely used.
Source: Leibniz Institute for Food Systems Biology; Specialist article: Journal of Agricultural and Food Chemistry, doi: 10.1021/acs.jafc.4c00714