Characterisation of aroma active compounds in black truffles (Tuber melanosporum) and summer truffles (Tuber aestivum) by gas chromatography-olfactometry.

Abstract The aromatic composition of two different species of truffles (black and summer) was evaluated by gas chromatography–olfactometry (GC–O). Volatiles released by the truffles at 25 °C for 7.5 h were collected in a trapping system consisting of 400 mg of LiChrolut EN kept at 0 °C and further eluted with dichloromethane/methanol (95:5). The extract was analysed by two different GC–O strategies: (1) a semiquantitative GC–O study using a panel composed of nine individuals, (three of them truffle experts) and (2) an AEDA (aroma extract dilution analysis) experiment with a small panel of two judges. The results show that the aroma emitted by a typical black truffle is due to at least 17 different aroma molecules, six of which are reported for the first time: 1-hexen-3-one, 2-methyl-3-furanthiol, furaneol, 3-ethylphenol, 3-propylphenol and 5-methyl-2-propylphenol. The most important aroma compounds of black truffle aroma are 2,3-butanedione, dimethyl disulphide (DMDS), ethyl butyrate, dimethyl sulphide (DMS), 3-methyl-1-butanol and 3-ethyl-5-methylphenol. Quantitatively, black truffle emits mostly 3-ethyl-5-methylphenol (more than 50% of the total aroma molecules emitted), 5-methyl-2-propylphenol, β-phenylethanol and 3-ethylphenol. In the case of summer truffle, the most important aroma molecules are DMS, DMDS, methional, 3-methyl-1-butanol, 1-hexen-3-one and 3-ethylphenol. From the quantitative point of view, summer truffle emits mainly β-phenylethanol, DMS and 3-ethylphenol, but the emission is up to 100 times less than that of black truffles.