Differentiation of Truffle Species (Tuber spp.) by 1H NMR Spectroscopy and support vector machine

Abstract

The price of different truffle types varies according to their culinary value, sometimes by more than a factor of ten. Non-professionals can hardly distinguish the species within the white or black truffles by eye, which makes the possibility of food fraud very easy. Therefore, the identification of different truffle species (Tuber spp.) is an analytical task that could be solved in this study. The polar extract from a total of 80 truffle samples were analyzed by 1H NMR spectroscopy in combination with chemometric methods covering five commercially relevant species. All classification models were validated with nested cross-validation. The two very similar looking and closely related black representatives Tuber melanosporum and Tuber indicum could be classified 100% correctly in direct comparison. The most expensive truffle Tuber magnatum could be distinguished 100% from the other relevant white truffle Tuber borchii. Furthermore, signals for a potential Tuber borchii, and a potential Tuber melanosporum marker for targeted approaches could be detected and the corresponding molecules were identified as betaine and ribonate. A model covering all five truffle species Tuber aestivum, Tuber borchii, Tuber indicum, Tuber magnatum and Tuber melanosporum was able to correctly discriminate between all species.