Wake up and smell the coffee

Civet cats in the Western Ghats like their coffee. Not brewed, with milk on the side, but the fruit of the coffee plant. They digest the flesh of the fruit and poop out the seeds. And these excreted seeds are the source of one of the world's most expensive coffee beans.

Although civet coffee is not very popular in India, a similarly obtained coffee called Kopi Luwak in Indonesia is in great demand worldwide. The beans cost $600–$1,300 a pound, and the coffee is often described as smooth, earthy, and not overly bitter. Now, a new study (bit.ly/Civet-Poop) by researchers from the Central University of Kerala has shown that this coffee gets its unique flavour from fatty acids and esters in civet beans.

The researchers compared robusta coffee beans from plants with the robusta civet-pooped beans. The study found that scat-derived beans were larger than manually collected beans. "On combined morphometry and chemical parameters, the beans of two types were not very distinct," the study states.

The researchers assessed the two types for volatile and semi-volatile compounds, conducting a Fatty Acid Methyl Ester (FAME) profile. While the two kinds of beans did not differ in protein and caffeine levels, civet scat beans had a higher fat content, with especially rich levels of caprylic acid and capric acid methyl esters. "Our hypothesis says that the gut microbes in the civet cause a natural fermentation of the bean and alter the bean chemistry," says Ramit Mitra, first author of the paper. The bacterium Gluconobacter is known to dominate the gut of Asian civets. The researchers believe that the enzymes produced by these bacteria help ferment the beans, contributing to their distinct flavour.

"A gap in the study is that we have not used roasted beans (for analysis)," says Palatty Allesh Sinu, one of the authors of the study and Associate Professor of Zoology at the university. Roasting, a key step in coffee production, enhances the aroma and taste. The researchers now plan to investigate the impact of roasting on the chemical composition of the beans. They also aim to identify the Gluconobacter enzymes that act on the beans, facilitating their fermentation. Precisely identifying the enzymes involved in the process may pave the way for artificially producing civet coffee in industrial conditions, Sinu says.