Soil bacteria contribute to the taste and smell of white truffles
Soil bacteria contribute to the taste and smell of white truffles
September 30, 2014
Tuber magnatum. Credit: Richard Splivallo
Truffles, along with caviar, are among the most expensive foods in the world. Because they grow underground, people use trained dogs or pigs to find them. But the distinctive smell of truffles is not only of interest to gourmets. A group of German and French scientists under the direction of the Goethe University Frankfurt have discovered that the smell of white truffles is largely produced by soil bacteria which are trapped inside truffle fruiting bodies.
White truffles from the Piedmont region in Italy can reach 5,000 Euro per kilogram, and black truffles from the Périgord region in Southern France as much as 2,000 Euro per kilogram. Particularly large specimens even fetch prices of up to 50,000 Euro per kilogram at auctions. Connoisseurs search for the precious delicacies near hazelnut trees, oaks and some species of pine. This is because truffles grow in a symbiotic relationship with the trees. For scientists truffles are therefore a model organism to investigate how symbiosis evolved between plants and fungi.
Truffles are also useful to study fungal smell and flavour. Understanding how flavours are created is indeed very important to the food industry. Yeasts and bacteria which make cheese and wine have been researched in depth, but little is known about how the flavour of other organisms, including truffles, is created.
Over the past 10 years, researchers already suspected that micro-organisms trapped inside truffle fruiting bodies contributed to the flavour. "When the genome of the black Perigord truffle was mapped in 2010, we thought that the fungus had sufficient genes to create its flavour on its own", junior professor Richard Splivallo from the Institute for Molecular Life Sciences at the Goethe University explained.
The team made up of German and French scientists studied the white truffle Tuber borchii. It is native to Europe but has been recently introduced in New Zealand and Argentina. The researchers were able to show that bacteria produce a specific class of volatile cyclic sulphur compounds, which make up part of the distinctive truffle smell. Dogs and pigs are able to find truffles underground thanks to the slightly sulphuric smell.
"However, our results cannot be transferred to other types of truffles", Splivallo says, "because the compounds we investigated are only found in the white truffle Tuber borchii." For this reason, in the future they plan to study compounds which are found in the Périgord and Piermont truffles and are common to all types of truffles. "We don't just want to know which part of the truffle flavour is produced by bacteria. We are also interested in how the symbiosis between fungi and microorganisms has evolved and how this benefits both symbiotic partners."
Tuber uncinatum. Credit: Richard Splivallo
Credit: Richard Splivallo
Provided by: Goethe-Universität Frankfurt am Main
0 shares
New species of truffle found in Finland
May 16, 2013
A species of truffle that is considered to be rare has been found for the first time in Finland. Previously it has been thought to exist only in the Pacific Northwest region of the United States. The truffle was found in ...
How black truffles deal with the jumpers in their genome
July 31, 2014
The black truffle uses reversible epigenetic processes to regulate its genes, and adapt to changes in its surroundings. The 'methylome' - a picture of the genome regulation taking place in the truffle, is published in the ...
Scientists unearth secrets of Perigord truffles, the culinary 'black diamond'
December 4, 2013
Just in time for the holidays when cooks in France and elsewhere will be slipping bits of the coveted black Périgord truffle under their turkeys' skin for a luxurious flavor, scientists are revealing the secrets that give ...
Climate change 'may make truffles a German delicacy'
July 22, 2011
Truffles, a luxury delicacy in French and Italian cuisine, may soon be adding flavour to blander dishes, as it migrates further north amid climate change, a Swiss scientist said Friday.
Climate change threatens French truffle, scientists say
November 27, 2012
Scientists said on Tuesday they had proof that climate change was hitting the Perigord black truffle, a delight of gourmets around the world.
Scientists scent breakthrough in truffle trafficking
March 28, 2010
One of Europe's gastronomic jewels, the fabled black Perigord truffle, has been genetically unravelled, a feat that could doom fakers who pass off inferior truffles as the real thing, scientists said on Sunday.
Recommended for you
Study provides evidence on movement of potato famine pathogen
December 28, 2016
New North Carolina State University research delves into the movement and evolution of the pathogen that caused the Irish potato famine in the 1840s, which set down roots in the United States before attacking Europe.
Genome study reveals 'gray zone' of animals transitioning from one species to two
December 27, 2016
There is usually no ambiguity about species delineation when distant lineages are compared. For instance, there is no doubt that dogs and cats belong to two different species. However, such distinction becomes less clear-cut ...
Jawing away: Bahama pupfish study identifies candidate genes driving food-niches
December 27, 2016
Within the salty lakes of the Bahama's San Salvador Island is an amazing diversity of fishes that may rival Charles Darwin's finches in the Galapagos.
Scientists develop novel assay to decode functional elements of genome
December 27, 2016
One of the most profound changes in the life of an organism is what Antonio Giraldez calls "embryonic puberty": the stage when an early embryo stops taking instructions from its mother on how to develop and activates its ...
Oxytocin enhances social affiliation in chimpanzee groups
December 27, 2016
The high costs of individuals going to war is perplexing. Individuals are willing to suffer costs in order to benefit their own group, through cooperating and supporting their fellow group members and acting with hostility ...
Stability without junctions—cadherin prevents cortical deformation
December 27, 2016
Scientists from the Mechanobiology Institute, Singapore (MBI) at the National University of Singapore (NUS) have discovered that cadherin clusters, which are well known for forming junctions between cells, also play a role ...