Microorganism growth profiles during fermentation of Gayo Arabica wine coffee

Abstract

Coffee is a non-alcoholic beverage that is consumed globally due to its specific flavour and functional properties. Nowadays coffee is diversified based on its coffee varieties, brewing methods, and bean processing techniques. Wine coffee is a commercial name for fermented coffee, a new coffee diversification product. Wine coffee is produced by fermenting coffee cherries for 30 to 60 days. As a new product, the process is not well studied. This research aims to explore the microorganisms’ activity and its profile growth during 30 days of fermentation. The documentation of pH and temperature, and microbial sampling during coffee cherry fermentation were conducted seven times, started at 0 days; 2 days; 4 days; 6 days; 8 days; 10 days; 12 days; 14 days; 16 days; 20 and 30 days. The results showed that pH decreases and temperature increases during fermentation. pH started from 5.0 and down to 3.9 when fermentation is terminated after 30 days, whilst the temperature slightly changes from 25°C to 30°C. The microorganism’s population shows the presence of yeast, lactic acid (LAB) and acetic acid bacteria (AAB) in wine coffee production. The yeast population increases in the mid fermentation as the cherries are damaged and provide suitable nutrition for the yeast. LAB also co-exists at a similar stage. Further research should be done, especially to understand the interaction mechanism between yeast and yeast, yeast and LAB, and yeast and AAB.

Isolation and Characterization of Yeast From Fermented Semeru Arabica Wine Coffee Cherries

“…This research employs an experimental approach by fermenting Semeru Arabica coffee cherries for 30 days. This extended fermentation period, compared to the 1-2 days used in regular coffee processing (Sulaiman and Hasni, 2022), aims to develop the characteristic taste and aroma associated with wine coffee. Isolation and screening were performed and followed by ethanol and temperature resistance analysis.…”

“…Exploration of yeast diversity during wine coffee processing is necessary to find out the potential yeast that exists in fermented Semeru Arabica wine coffee cherries. Previous research conducted by (Sulaiman and Hasni, 2022) indicated that yeast is more dominant at the beginning and after 20 days of fermentation. Yeast metabolism initiates the growth of other microorganisms (such as LAB and AAB) and inhibits the growth of mycotoxins in filamentous fungi.…”

“…After that, there was secondary fermentation in the form of lactic acid fermentation by LAB, which brings out the aroma of wine and complex taste. The fermentation process, followed by the drying or aerobic natural fermentation, would trigger the growth of AAB, which converts alcohol into acetic acid (Sulaiman and Hasni, 2022).…”

“…According to Sulaiman and Hasni (2022), wine coffee is produced from the fermentation process of coffee cherries for 30-60 days and dried directly in sunlight for about 3-6 weeks. The fermentation process of wine coffee aims to eliminate bitterness so as to improve the quality of coffee products caused by compounds from the degradation of the mucous layer by microorganism activity and is often correlated with an increase in the selling price of products that have a taste, such as wine (Juanda et al, 2022).…”

Microbial Succession During the Fermentation of Semeru Arabica Coffee in Wine Coffee Production

“…Arabica Semeru coffee produces compounds with taste notes of green apple, caramel, and brown sugar (Maligan et al, 2020). Wine coffee fermentation lasts for 30-60 days under facultative anaerobic conditions and involves indigenous microbes such as yeasts, lactic acid bacteria, and acetic acid bacteria (Sulaiman and Hasni, 2022). Microbes utilize the mucilage layer, rich in pectin and sugar, as a substrate.…”