Discrimination of truffle fruiting body versus mycelial aromas by stir bar sorptive extraction

Stir bar sorptive extraction (SBSE) was applied in head space mode (HS), coupled with GC/MS, to compare the aroma profile of three truffle species. A total of 119 volatile organic compounds (VOCs) were identified from the fruiting bodies, of which 70 were not yet described in truffles and 60 in fungi. VOCs profile showed a high intra- and inter-specific variability, with alcohols and sulfur compounds dominating the HS of Tuber borchii and, alcohols, aldehydes and aromatic compounds the HS of T. melanosporum and T. indicum. Despite these variations, eight VOCs markers could be identified allowing the discrimination of the three species. Additionally, T. borchii and T. melanosporum both distinguished themselves from T. indicum due to higher aroma content and larger variety of sulfur containing compounds. Mycelial VOCs production was also investigated under two cultural conditions and led to the identification of eight VOCs. On one side, seven of them were also detected in the fruiting body, confirming their mycelial origin. On the other side, the total absence of some class of compounds (i.e. sulfur) in the mycelium raises questions about their origins in the fruiting bodies and confirms deep metabolic changes between the reproductive (fruiting body) and vegetative (mycelium) stages.