Fermentation of cocoa beans requires precise collaboration among two bacteria, and yeast

June 10, 2014

Good chocolate is among the world's most beloved foods, which is why scientists are seeking to improve the product, and enhance the world's pleasure. A team of researchers from Germany and Switzerland—the heartland of fine chocolate—have embarked upon a quest to better understand natural cocoa fermentation and have published findings ahead of print in the journal Applied and Environmental Microbiology.

"Our studies have unraveled the metabolism of the rather unexplored acetic acid bacteria in the complex environment," says corresponding author Christoph Wittmann of Saarland University, Saarbruecken, Germany

In the study, Wittmann and his collaborators from the Nestle Research Centre, Lausanne, Switzerland, simulated cocoa pulp fermentation in the laboratory. They mapped metabolic pathway fluxes of the acetic acid bacteria, feeding them specific isotopes that could easily be tracked. Wittmann compares the process to viewing the flows of city traffic from the sky. "We could see what they eat and how they use the nutrients to fuel the different parts of their metabolism in order to grow and produce extracellular products," he says.

The key molecule to initiate flavor development is acetate, says Wittmann, noting that "The intensity of the aroma from a fermented bean is amazing."

Production of acetate requires two major nutrients: lactate and ethanol. These are produced by , and yeast, respectively, during the initial fermentation of cocoa pulp sugars, says Wittmann.

The bacteria then process these simultaneously, via separate metabolic pathways, ultimately producing acetate from them.

"This discovery reveals a fine-tuned collaboration of a multi-species consortium during fermentation," says Wittman. And that may help improve selection of natural strains for better-balanced starter cultures.

Explore further: New study shows that cocoa flavanols can be preserved during cooking and baking

More information: The manuscript can be found online at aem.asm.org/content/early/2014/05/12/AEM.01048-14.full.pdf+html . The final version of the article is scheduled for the August 2014 issue of Applied and Environmental Microbiology.

Related Stories

A channel of unexpected significance

August 13, 2012

Scientists from the research groups of Prof. Dr. Susana Andrade and Prof. Dr. Oliver Einsle, members of the Institute of Organic Chemistry and the Cluster of Excellence BIOSS, the Centre for Biological Signalling Studies ...

Recommended for you

Researchers design first artificial ribosome

July 29, 2015

Researchers at the University of Illinois at Chicago and Northwestern University have engineered a tethered ribosome that works nearly as well as the authentic cellular component, or organelle, that produces all the proteins ...

Studies reveal details of error correction in cell division

July 29, 2015

Cell biologists led by Thomas Maresca at the University of Massachusetts Amherst, with collaborators elsewhere, report an advance in understanding the workings of an error correction mechanism that helps cells detect and ...

Researchers discover new type of mycovirus

July 29, 2015

Researchers, led by Dr Robert Coutts, Leverhulme Research Fellow from the School of Life and Medical Sciences at the University of Hertfordshire, and Dr Ioly Kotta-Loizou, Research Associate at Imperial College, have discovered ...

Stressed out plants send animal-like signals

July 29, 2015

University of Adelaide research has shown for the first time that, despite not having a nervous system, plants use signals normally associated with animals when they encounter stress.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.