Fermentation of coffee beans with inoculation of bacillus subtilis and its impact on coffee sensory quality

Abstract

The aim of this research was to study the coffee fermentation with inoculation of Bacillus subtilis isolated from civet (Paradoxorus hermaphroditus) as starter culture. The quality of coffee was evaluated by sensory quality (cup test). Two treatments were carried out: control/coffee non-inoculated starter culture (treatment F) and coffee inoculated with a Bacillus subtilis starter culture (treatment G). The fermentations were conducted for 48 h in triplicate. A inoculation of Bacillus subtilis as a starter culture cause a decrease in pH and increase in total titratable acidity of coffee fermentation solution. A panel of five trained coffee testers (Q-grader from Gayo Cupper’s Team) evaluated the samples. Ten sensorial attributes analyzed were fragrance/aroma, flavor, aftertaste, acidity, body, uniformity, balance, sweetness, cleanliness and overall. The result showed that the use of Bacillus subtilis starter culture improved quality of coffee fermentation. The aroma, flavour, aftertaste, body, balance and overall were increased. The cupping score total of coffee increased from 82.83 to 84.33. Metabolites analysis should be further investigated to confirm this result, especially organic acids compound.