by Ben Taub
Oompa-Loompas may soon find themselves out of a job thanks to a team of Belgian microbiologists and chocolatiers, who have managed to develop a series of yeast hybrids capable of manipulating the flavor and quality of chocolate. Publishing their findings in the journal Applied and Environmental Microbiology,
the researchers claim that the hybrids could provide a superior and more economical method of producing boutique chocolate than those currently employed.
According to the study authors, gourmet and boutique chocolate is the fastest-growing segment of the global chocolate industry, with consumers increasingly seeking out unique flavors and high quality. Until now, these flavors had been generated by the addition of extra ingredients to the final product, although the new method could enable chocolatiers to naturally alter the taste of their confectionary during the fermentation stage.
It has long been known that the mixture of microbes present during the fermentation of cocoa beans can have a major impact on the flavors released, which is why producers tend to seek out certain strains of yeast that can outcompete other organisms at high temperatures. In doing so, they ensure that unwanted bacteria don’t get the chance to degrade the cocoa pulp and cause foul-tasting compounds to enter the mixture.
The researchers decided to take this process one step further by creating strains of yeast that not only displayed exceptional tolerance to heat, but which could produce a wide variety of aromas. Their results showed that this is indeed possible, since different yeast strains were found to release different combinations of esters during the fermentation process.
Esters are fragrant organic compounds often used in perfume. They have also played a major role in wine production for many years, and are credited with determining the fruitiness of the drink. Similarly, craft beer brewers place great importance on the type of yeast used during fermentation, since the esters released can make or break the final product.
Previously, the importance of esters in chocolate production had not received a great deal of attention since it had been assumed that most of these were broken down duringconching, which occurs after fermentation and involves intense heating of the cocoa. However, the researchers discovered that, while most short-chain esters did indeed evaporate during conching, longer-chain compounds survived and remained present in the chocolate itself. Since different yeast hybrids generated different combinations of esters, the team discovered that the choice of yeast directly influenced the fruitiness of the chocolate.
To test this, they produced a number of samples, each of which was fermented using a different yeast hybrid. These were then subjectively analyzed by a panel of nine experts supplied by world-renowned chocolatier Barry Callebaut.
The results of the study showed that the fruitiest chocolate of all was produced using hybrid H40 and contained the highest concentration of isoamyl acetate, suggesting that acetate esters may be the most influential in the generation of fruity chocolate flavors.
