A microbial chocolate factory
Most of the time we consider microbes in the context of disease. Often overlooked is the crucial role microbial communities play in industrial processes, ecosystems, and even the food we eat. As long as human societies have existed, people have sought ways to manipulate and preserve food. One ancient strategy–fermentation–has been used to enrich the flavor and transform the sensory profiles of food and drink, driven by yeast and bacteria whose metabolism releases a variety of chemicals. Surprisingly, the biology underlying a ubiquitous sweet treat, chocolate, was poorly understood–until now.
One group in the UK monitored cocoa beans, the raw precursors to chocolate, as they fermented over 7 days in cocoa farms across three regions in Colombia: Santander, Antioquia, and Huila. Besides tracking physical conditions such as temperature and pH, they produced molecular and microbial profiles from these samples, identifying essential “flavor-determining compounds” and the identities of the bacteria and yeast that likely produce them. They found that, according to professional taste testers, changes in flavor profiles across sites correlated with the presence of specific flavor-associated compounds produced by particular microbes. Further, the researchers identified an assembly of microbes involved in cocoa bean fermentation across all locations that lays the groundwork for development of starter cultures in chocolate production.
These developments can help increase quality yields of unique and, particularly, organic chocolate products that continue to grow in demand yet make up a small portion of the total cocoa market. As it turns out, the debate between dark, milk, or white chocolate may soon be overshadowed by the nutty, floral, or fruity notes imparted by the microbial oompa loompas of chocolate production!
This study was led by David Gopaulchan, supervised by corresponding authors David E. Salt and Gabriel Castrillo
Managing Correspondent: David Zahrah
Press Article: Microbial chocolatiers of fine flavour, Applied Microbiology
Original Research Article: A defined microbial community reproduces attributes of fine flavour chocolate fermentation, Nature Microbiology
Image credit: Measure the temperature of the fermented cocoa beans. Vecteezy