Coffee is a beverage that serves as fuel for people around the world. The beverage has fans across the globe who are addicted to the taste and flavour of this comforting beverage. A recent study has revealed what exactly gives the caffeinated drink its unique and addictive taste- a bunch of bacteria! The study, carried out by a team of researchers from Universiteit Brussel, in Belgium, at an experimental farm in Ecuador, has shown that lactic acid bacteria which are responsible for the longer fermentation of beans of coffee, lend the drink a better taste. This finding goes against popular belief that says otherwise.
Explaining the process of coffee-making, lead investigator Luc De Vuyst, Professor at the Vrije Universiteit Brussel, in Belgium said, "A cup of coffee is the final product of a complex chain of operations: farming, post-harvest processing, roasting and brewing." There are a number of ways of post-harvest processing, including the most common dry and wet processing. The process that is used in preparing Arabica and specialty coffees- wet processing- is the very step that involves fermentation of coffee beans and the team of researchers concluded that longer period of fermentation impact coffee quality. The results of the study were published in the Applied and Environmental Microbiology journal. The team found that during the extended fermentation, the leuconostocs genus of lactic acid bacteria declined and lactobacilli increased.
Leuconostocs are also used in the fermentation of cabbage to sauerkraut and in sourdough starters. The fermentation process encourages the proliferation of lactobacilli. De Vuyst said, "It is challenging to draw a causal link between the microbiota and the volatile compounds in the beans -- those compounds that contribute to the coffee's smell- since many of these compounds can be of microbial, endogenous bean metabolism, or chemical origin." He further conjectured that the growth of lactobacilli may have had a protective effect on the quality of the coffee, by preventing the growth of undesirable microbes which may lead to flavours that spoil the taste of the coffee.
Besides lactobacilli, enterobacteria, yeasts, acetic acid bacteria, bacilli and filamentous fungi are some other micro-organisms that play a role during wet fermentation of coffee beans. However, De Vuyst says that it is still not known how exactly most bacteria influence the fermentation process.
(With IANS inputs)