Wine microbes can help make better chocolate

For decades, scientists have sought to improve cocoa fermentation by controlling the microbes involved. New research has finally found that the same species of yeast used in the production of beer, bread, and wine works particularly well in chocolate fermentation.

The research by a team of Belgian researchers was published in Applied and Environmental Microbiology.

"Chemical analyses as well as tasting the chocolate showed that the chocolate produced with our best yeasts is much better and more consistent than the chocolate produced through natural fermentation," said Kevin Verstrepen from University of Leuven, Belgium.

"Moreover, different yeasts yielded different chocolate flavours, indicating that it would be possible to create a whole range of specialty chocolates to match everyone's favourite flavour," Verstrepen added.

The investigators characterized more than 1,000 strains of Saccharomyces cerevisiae, mostly from the alcoholic beverage industry, but including some from cocoa farms.

Some of the best performers came from the latter, and others came from the beer, wine, bioethanol, and sake industries, said Verstrepen.

After the harvest, cocoa beans are collected and placed in large wooden boxes, or even piled on the soil at the farms where they are grown.

At this point, the beans are surrounded by an unappetising white, gooey pulp composed of sugars, proteins, water, pectin, and small amounts of lignin and hemicellulose.

Microbes that are present in the farm environment then go to work consuming the pulp through fermentation.

Differences among the microbes at different farms result in differences in flavour and quality of the resulting chocolate.

"Some microbes produce bad aromas that enter into the beans, giving rise to chocolate with a foul taste, while others do not fully consume the pulp, making the resulting beans difficult to process," Verstrepen said.

"We were looking to find or develop the best microbes that result in the best chocolate," he said.

These, he said, could be added immediately at the onset of fermentation, allowing them to outcompete less desirable microbes, enabling consistent production of high quality chocolate.