Effect of civet-derived bacteria and fermentation duration on basic physical characteristics of robusta green coffee beans

This study investigates the effect of civet-derived bacterial fermentation on the yield, moisture content, and density of Robusta green coffee beans. The research focused on basic physical characteristics as preliminary indicators of bean quality before further chemical and sensory evaluation. Robusta coffee cherries were fermented using civet-derived bacteria at three inoculum concentrations (0%, 50%, and 100%) and for different fermentation durations (1, 2, and 3 days). The resulting beans were analyzed for yield, bulk density, and moisture content. The experiment was arranged in a Completely Randomized Design (CRD) with two factors: civet-derived bacterial concentration and fermentation duration, each replicated three times. Data were analyzed using ANOVA followed by DMRT at a 5% significance level. The results showed that the civet-derived bacterial concentration significantly affected the yield and density, but did not influence the moisture content of the green coffee beans. In contrast, fermentation duration and its interaction with bacterial concentration had no significant effects on any of the observed parameters. The highest yield (38.06%) and stable physical characteristics were obtained at the 50% inoculum concentration, indicating that moderate bacterial activity provided the most efficient mucilage degradation without causing excessive bean-mass loss. These findings suggest that civet-derived bacterial fermentation at a moderate concentration can enhance the physical quality and structural integrity of Robusta green coffee beans, serving as a potential pre-treatment step for improving their chemical and sensory properties.