Non-volatile compounds of unwashed Gayo Arabica coffee (Coffea arabica) with anaerobic fermentation process

Abstract

Coffee is a hot drink made from the roasted and ground seeds (coffee beans) of a tropical shrub with a preferred flavour, which is consumed by many people. Furthermore, its flavour is influenced by the chemical composition of green beans that goes through series of processing such as fermentation. The chemical composition of green beans with fermentation process in the process without washing is not well-known in Gayo coffee. This study aims to analyse the effect of anaerobic fermentation on chemical composition of green beans and to enhance its quality. The coffee fruit was processed and fermented for 0 to 48 hours. Citric and malic acids varied and showed positive quality in the process of Pulp Natural (PN) and Black Honey (BH), while propionic acid was only discovered in the process of Drying (D), which indicated a negative quality. Sucrose tends to increase in PN and BH. Glucose and fructose were lower than sucrose, and chlorogenic acid increased, while trigonelline tends to decrease from all processes. Caffeine had very low levels after the fermentation process. In conclusion, this research indicated that the anaerobic fermentation process in PN and BH produced generally desirable flavour precursors.