Isotopes could unmask truffle fraud

Abstract

Alba white truffles, Tuber magnatum Pico, are among the priciest of delicacies, fetching almost $7,000 per kilogram last season and making them a target for fraud. A new method offers a way to distinguish bis(methylthio)methane—the key Alba white truffle flavor molecule—in real truffles from a synthetic version in food (Anal. Chem. 2018, DOI: 10.1021/acs.analchem.8b00386). Bis(methylthio)methane from natural truffles contains carbon-12 and carbon-13 in a ratio reflecting the environment in which the fungus grew. Meanwhile, the synthetic molecule’s ratio reflects its origins in petrochemical or plant-based feedstocks. Luigi Mondello of the University of Messina and his colleagues determined those relative amounts of 12C and 13C with an isotope ratio mass spectrometer, analyzing both synthetic bis(methylthio)methane and natural bis(methylthio)methane that evaporated from white truffles. The researchers then tested samples of commercial truffle-flavored foods including olive oil, pasta, and cheese. Those labeled as containing lower-quality truffles and added truffle aroma had the isotopic