Tartuf

Truffles are subterranean fungi that grow on tree roots. They are found underground, usually with oak or hazelnut trees. The black Périgord truffle (Tuber melanosporum) is named after the Périgord region in France and is harvested in late autumn and winter. The white truffle (Tuber magnatum) is mainly found in Italy, but also in other parts of Southern Europe, as well as Thailand.

This note in PREMIEREPEAU. Albâtre Sépia. Sample all seven extraits in the Discovery Set.

Habitat and growth

Black truffles associate with oaks, hazelnut, cherry, and other deciduous trees. Black truffles grow at a depth of 5 cm to 50 cm as ectomycorrhizae, preferably in loose calcareous soil. The white truffle grows symbiotically with oak, hazel, poplar and beech. The soils of the white truffle have an average pH of about 7.7 and range from neutral to alkaline. The Périgord truffle is restricted to alkaline environments.

The symbiosis of holm oak saplings and black truffles has been shown to improve photosynthesis and root growth in the plant. Black truffles suppress the growth of plants around their symbiont, creating the impression of a burnt area. Truffles draw carbohydrates from the tree and use them to construct filaments that push through the soil in search of other rootlets. The mycorrhiza with their filaments are far better than an uncloaked rootlet at collecting nutrients for the tree.

No one has ever managed to grow a truffle in the laboratory without a tree. A truffle farmer does not plant truffles but oak trees, since truffles grow only near the roots of certain trees. In cultivation, the first fruiting bodies can be harvested about 4-10 years after the trees are planted. Black truffles are now also cultivated in Australia and New Zealand. In 1937, France produced about 1,000 metric tonnes of black truffles.

Aroma and chemistry

Without smell, a truffle would rot in place and not fulfill its function of spreading seed. Truffles possess significant variability in their aroma profiles from species to species. Among the hundreds of aroma active compounds in truffles, 2-methylbutanal, 3-methylbutanal, dimethyl disulphide (DMDS) and dimethyl sulphide (DMS) are the most common natural aroma compounds. Dimethyl sulfide is the main volatile product of various truffles.

The volatile compounds that contribute to the aroma of the black truffle include 2-methyl-1-butanol, isoamyl alcohol, 2-methylbutyraldehyde and 3-methylbutyraldehyde, as well as traces of sulfur compounds. 1-Octen-3-ol was detected in high amounts in raw T. melanosporum. Several species of yeast, which produce part of the aromatic compounds, have been isolated from Tuber melanosporum and Tuber magnatum. If black truffles are stored at room temperature, the aromatic compounds dissipate, while storage around the freezing point leads to an increased synthesis of these compounds.

2,4-Dithiapentane is an organosulfur compound and the simplest alkyl dithioether. It is also named bis(methylthio)methane. 2,4-Dithiapentane is found as an aromatic component in some truffle varieties. It is the key odorant of Tuber magnatum. Thiophene derivatives appear to be produced by bacterial symbionts living in the truffle body. In Tuber borchii, thiophene derivatives, in particular 3-methyl-4,5-dihydrothiophene, were the main contributors to the human-sensed aroma.

Authenticity

Cheaper Tuber borchii are sold for T. magnatum. In some cases, scent is enhanced with petroleum-based essence such as bis(methylthio)methane. Isotopic analysis is the most reliable detection of fraud or of mislabelling. The carbon isotope ratio (δ13C) of bis(methylthio)methane in genuine truffles lies between -43 and -34‰, and synthetic aroma gives more negative values.

In a fragrance

Truffle is a base-note signature in PREMIEREPEAU's Albâtre Sépia — paired with white truffle ink, tonka bean, iso E super and frankincense. The accord uses both the dithiomethane sulphur signal and a fatty-earthy mushroom alcohol backbone (oct-1-en-3-ol) to recreate the truffle's full register without the literal extract.