Performance of Mixed-Microbial Culture from Civet Fecal Suspensions on Physicochemical Composition of Wet Fermented Arabica Coffee

Abstract

This study aimed to evaluate the effects of mixed microbial culture from civet fecal suspension used as the inoculum for the fermentation of Arabica coffee. The type of Arabica coffee used for the research was the unpeeled coffee or the Arabica coffee cherries. Different proportion of inoculum introduced was thoroughly evaluated to assess the appropriate concentration of inoculum (0-40% inoculums represented in treatment 0-4 or T0 to T4) that would be applied to the fermentation of Arabica coffee cherries. Results revealed that treatment 4 (T4) containing 40% of the inoculum could degrade the sugar of the coffee beans faster than that of the other treatments in which within 24 hours of the incubation approximately 84% of the sugar was converted. T4 also reached the lowest caffeine content (1.8%) of the fermented coffee beans among other that of other treatments while the control had higher caffeine content (2.2%).This was substantially significant as the Arabica coffee cherries fermented with mixed microbial civet fecal suspensions can remarkably reduce the sugar and caffeine content of the Arabica coffee beans.

Carbohydrate Enrichment in In-Vitro Civet Coffee Fermentation: Impact on Arabica Coffee Beans

“…Glucose and starch were used in this experiment as these types of carbohydrate would generate different fermentation endproducts and may induce different types of fermentative microbes [16]. Hence, by supplementing these carbohydrates potentially could affect coffee fermentation and improve its quality [20]. This process was performed until the volume culture reached 500 ml.…”

“…Inoculum added to each reactor was 40% of the total volume. The concentration of inoculums used in this experiment was based on the previous study revealing that 40% of inoculums were a feasible concentration that could enhance conversion of sugar and caffeine in the fermentation of Arabica coffee [20].…”

“…A significant drawback of this conventional practice is the potential for irreproducible results due to contamination since the fermentation process occurs in an open environment. Coffee fermentation using a defined microbial culture could potentially offer a controlled process and more reproducible results compared to the traditional practice [20,21].…”

“…However, the use of a pure microbial culture may not significantly enhance the physicochemical properties of coffee, as it tends to alter a specific component to produce a particular fermentation end-product [25]. In contrast, mixed microbial cultures could potentially enhance the physicochemical characteristics of coffee [20] and promote the desired tastes and aroma [17]. This is attributable to the diverse types of microbes and/or microbial consortium present in mixed cultures [16,26,27].…”

“…The introduction of a mixed microbial culture, derived from civet fecal suspension, to coffee fermentation could aid in the oxidation and conversion processes of the compounds in coffee pulp and mucilage, forming various metabolites [20]. This is attributed to the inoculum from civet fecal suspension, comprising a diverse array of digestive microorganisms adapted to the fermentation of coffee cherries [20]. This process could not only reduce undesirable coffee components, such as caffeine, but also generate fermentation end-products, contributing to the modulation of coffee flavor and aroma [17,28].…”