The genome for the Périgord truffle was published in 2010. Considering that these special truffles go for 1000-2000 ($1300-2700) an ounce, the genome has been under-exploited by culinary scientists and molecular gastronomists…until recently when specialists in bioinformatics and proteomics got together to mine the secrets of Brillat-Savarin‘s “diamond of the kitchen”. The resulting paper, released today in the Journal of Proteome Research, seeks to unlock the “puzzling biology of the Black Périgord truffle Tuber melanosporum“.
As ectomycorrhizal fungi, truffles exist in symbiotic relationships with tree roots (black truffles like both oak and hazelnuts). Cultivation first occurred successfully in France when phylloxera destroyed viticulture in France (temporarily) and made available huge tracts of land for the creation of truffle groves. Much of that knowledge was lost in the wars that followed and the trees eventually reached the end of their truffle-producing life cycle. Attempts to start again today are rife with price control politics.
I was amazed to find that I LOVED LOVED LOVED truffles because I dislike mushrooms (something about their texture turns me off). I had truffles for the first time in a town called Stenay in Lorraine region of France. They were tender and aromatic and meaty without being meat. There wasn’t anything that I had eaten that compared to them and they filled a distinct niche that nothing else had in my vegetarian diet.
The smell. The lovely smell of good truffles–so good that Peter Mayle describes a truffle breakfast eaten with one’s head under the napkin to better capture the aroma. Amazingly, the new article reports that only nine enzymes are responsible for creating over 90 different odorants associated with the unique aroma of the black diamonds of Périgord! The authors note:
It is hardly surprising that such low numbers of enzymes were shown to be involved in the production of over 90 volatiles considering over 70% of the proteome is yet to be annotated. The potential to discover novel enzymes that could be of economic, medicinal, or other uses remains a tantalizing possibility.
Attempts have been made to capture this aroma to cheaply produce ‘truffled’ food. There is even a truffle-scented vodka! The food industry uses two chemicals (DMS and 2-methyl-1-butanol) predominant in the odor profile in order to produce a truffle flavour. A chemical called 2,4-dithiapentane is used to simulate the aroma in olive oils. Both DMS and 2,4-dithiapentane are derived from methanethiol, which is the key odor produced in human urine after metabolism of asparagus. The ability to detect this compound has a genetic component. I wonder if this influences one’s preference for truffles…something I am exploring in my on-going research on food preference, odors, and genes!
The Smell of Evolution 