For many years, researchers have played around with cacao fermentation by controlling the microorganisms involved. Raw cacao is prepared by cold-pressing un-roasted cacoa beans. The process keeps the enzymes in the cacoa intact and removes the fat (cacao butter). This is then used to make a type of chocolate. The majority of chocolate is made from cocoa powder; this is raw cacao that has been roasted at high temperatures.
Scientists in Belgium have discovered that the yeast used in the production of beer works very well in chocolate fermentation. This improved the quality beyond that produced by natural fermentation.
When cacao beans are collected they put into a vat and they are surrounded by a pulp composed of sugars, proteins, water, pectin, and small amounts of lignin and hemicellulose. The microorganisms found within the pulp initiate the fermentation process necessary for the production of chocolate. Because the composition of the microbes varies around the world, this affects the final taste of the chocolate.
To add consistency to the process and to produce an optimal flavor, researchers at the University of Leuven, and the Flanders Institute for Biotechnology, used the common brewing yeast Saccharomyces cerevisiae to supplement the fermentation process. The results, they report, from chemical analysis are of a good quality chocolate. The reason for the success is thought to be because yeasts used in brewing (and making sake or wine) can withstand much higher temperatures.
Further work has shown playing around with yeast types could lead to a new range of chocolates. Different types of yeasts yield different chocolate flavors. The researchers have begun experimenting with various hybrids, in order to enhance the process.
The findings have been published in the journal Applied and Environmental Microbiology. The research paper is titled “Application of a breeding strategy to generate robust yeast starter cultures for cocoa pulp fermentations.”
