On the trail of the truffle flavor

Soil bacteria contribute to the taste and smell

2014-09-30

(Press-News.org) This news release is available in German.

FRANKFURT. 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."

INFORMATION:

Publication: Splivallo R, Deveau A, Valdez N, Kirchhoff N, Frey-Klett P, Karlovsky P. (2014). Bacteria associated with truffle-fruiting bodies contribute to truffle aroma. Environmental Microbiology. DOI: 10.1111/1462-2920.12521

Information: Junior-Prof. Richard Splivallo, Institute for Molecular Bio Sciences, Campus Riedberg, Tel.: 0049(0)69/ 798- 42193, Splivallo@bio.uni-frankfurt.de.

The Goethe University is an institution with particularly strong research capabilities based in the European financial metropolis of Frankfurt. It celebrates its 100th year of existence in 2014. The university was founded in 1914 through private means from liberally-orientated citizens of Frankfurt and has devoted itself to fulfilling its motto "Science for the Society" in its research and teaching activity right up to the present day. Many of the founding donors were of Jewish origin. During the last 100 years, the pioneering services offered by the Goethe University have impacted the fields of social, societal and economic sciences, chemistry, quantum physics, neurological research and labour law. On January 1st, 2008, it achieved an exceptional degree of independence as it returned to its historical roots as a privately funded university. Today it is one of the ten universities that are most successful in obtaining external research funding and one of the three largest universities in Germany with centres of excellence in medicine, life sciences and humanities.

Publisher: The president of the Goethe University Frankfurt am Main. Editorial department: Dr. Anke Sauter, Science editor, Department Marketing and Communications, Grüneburgplatz 1, 60629 Frankfurt am Main, Phone: (069) 798-12498.

[Attachments] See images for this press release:

ELSE PRESS RELEASES FROM THIS DATE:

NASA ocean data shows 'climate dance' of plankton

2014-09-30

The greens and blues of the ocean color from NASA satellite data have provided new insights into how climate and ecosystem processes affect the growth cycles of phytoplankton—microscopic aquatic plants important for fish populations and Earth's carbon cycle. At the bottom of the ocean's food chain, phytoplankton account for roughly half of the net photosynthesis on Earth. Their photosynthesis consumes carbon dioxide and plays a key role in transferring carbon from the atmosphere to the ocean. Unlike the plant ecosystems on land, the amount of phytoplankton in the ocean ...

NASA support key to glacier mapping efforts

2014-09-30

Thanks in part to support from NASA and the National Science Foundation, scientists have produced the first-ever detailed maps of bedrock beneath glaciers in Greenland and Antarctica. This new data will help researchers better project future changes to glaciers and ice sheets, and ultimately, sea level. Researchers at the Center for Remote Sensing of Ice Sheets, or CReSIS, at the University of Kansas in Lawrence, Kansas, recently built detailed maps of the terrain beneath Greenland's Jakobshavn Glacier and Byrd Glacier in Antarctica. The results of this study were published ...

NASA-funded rocket has 6 minutes to study solar heating

2014-09-30

On Sept. 30, 2014, a sounding rocket will fly up into the sky – past Earth's atmosphere that obscures certain wavelengths of light from the sun -- for a 15-minute journey to study what heats up the sun's atmosphere. This is the fourth flight for the Very high Angular Resolution Ultraviolet Telescope, or VAULT, will launch from the White Sands Missile Range near Las Cruces, New Mexico. The instrument, now called VAULT2.0, has been refurbished with new electronics and an imaging detector to capture images more frequently than before. While in space, VAULT2.0 will observe ...

Deceptive-looking vortex line in superfluid led to twice-mistaken identity

2014-09-30

So long, solitons: University of Chicago physicists have shown that a group of scientists were incorrect when they concluded that a mysterious effect found in superfluids indicated the presence of solitons—exotic, solitary waves. Instead, they explain, the result was due to more pedestrian, whirlpool-like structures in the fluid. They published their explanation in the Sept. 19 issue of Physical Review Letters. The debate began in July 2013, when a group of scientists from the Massachusetts Institute of Technology published results in Nature showing a long-lived structure ...

New discovery approach accelerates identification of potential cancer treatments

2014-09-30

ANN ARBOR—Researchers at the University of Michigan have described a new approach to discovering potential cancer treatments that requires a fraction of the time needed for more traditional methods. They used the platform to identify a novel antibody that is undergoing further investigation as a potential treatment for breast, ovarian and other cancers. In research published online in the Proceedings of the National Academy of Sciences, researchers in the lab of Stephen Weiss at the U-M Life Sciences Institute detail an approach that replicates the native environment ...

Gene doubling shapes the world: Instant speciation, biodiversity, and the root of our existence

2014-09-30

What do seedless watermelon, salmon, and strawberries all have in common? Unlike most eukaryotic multicellular organisms that have two sets of chromosomes and are diploid, these organisms are all polyploid, meaning they have three or more sets of chromosomes—seedless watermelon and salmon have 3 and 4 sets of chromosomes, respectively, and strawberries have 10! While this might seem surprising, in fact most plant species are polyploid. Polyploidy, or genome doubling, was first discovered over a century ago, but only recently, with the development of molecular tools, has ...

Smithsonian scientists discover coral's best defender against an army of sea stars

2014-09-30

Coral reefs face a suite of perilous threats in today's ocean. From overfishing and pollution to coastal development and climate change, fragile coral ecosystems are disappearing at unprecedented rates around the world. Despite this trend, some species of corals surrounding the island of Moorea in French Polynesia have a natural protector in their tropical environment: coral guard-crabs. New research from the National Museum of Natural History's Smithsonian Marine Station scientist Seabird McKeon and the museum's predoctoral fellow Jenna Moore of the Florida Museum of Natural ...

Asthma symptoms kicking up? Check your exposure to air pollution

2014-09-30

ARLINGTON HEIGHTS, Ill. (September 30, 2014) – People who suffer from asthma may think there's not a lot they can do to control their asthma besides properly taking medications and avoiding allergic triggers. According to a new article in the Annals of Allergy, Asthma and Immunology, the scientific publication of the American College of Allergy, Asthma and Immunology (ACAAI), asthma sufferers can learn lessons about managing their asthma by examining their lifestyle. The woman described in the Annals article improved her asthma once she and her doctor determined her ...

High-dose vitamin D for ICU patients who are vitamin D deficient does not improve outcomes

2014-09-30

Administration of high-dose vitamin D3 compared with placebo did not reduce hospital length of stay, intensive care unit (ICU) length of stay, hospital mortality, or the risk of death at 6 months among patients with vitamin D deficiency who were critically ill, according to a study published in JAMA. The study is being posted early online to coincide with its presentation at the European Society of Intensive Care Medicine annual congress. A high prevalence of low vitamin D levels has been confirmed in patients who are critically ill. Many studies suggest that a low vitamin ...

Gut bacteria promote obesity in mice

2014-09-30

A species of gut bacteria called Clostridium ramosum, coupled with a high-fat diet, may cause animals to gain weight. The work is published this week in mBio®, the online open-access journal of the American Society for Microbiology. A research team from the German Institute of Human Nutrition Potsdam-Rehbruecke in Nuthetal observed that mice harboring human gut bacteria including C. ramosum gained weight when fed a high-fat diet. Mice that did not have C. ramosum were less obese even when consuming a high-fat diet, and mice that had C. ramosum but consumed a low-fat ...

LAST 30 PRESS RELEASES:

Personalised “cocktails” of antibiotics, probiotics and prebiotics hold great promise in treating a common form of irritable bowel syndrome, pilot study finds

Mobile device location data is already used by private companies, so why not for studying human-wildlife interactions, scientists ask

Test reveals mice think like babies

[Press-News.org] On the trail of the truffle flavor
Soil bacteria contribute to the taste and smell