The Influence of Bean Sprout Extract and Lactobacillus bulgaricus on the Caffeine Content and Flavor of Arabica-Robusta Coffee Fermentation

Coffee, an important agricultural product in Indonesia, contains caffeine which can have adverse effects on health. To reduce the caffeine content, this study explores the fermentation of Arabica-Robusta coffee using sprout extract as a nutrient source for microorganisms and the lactic acid bacteria species Lactobacillus bulgaricus. Experiments were conducted using a completely random design, with variations in the amount of L. bulgaricus (10, 15, 20, 25, 30, and 35 mL) and sprout extract (10, 20, 30, 40, 50, and 60 mL) as variables. The dried coffee beans were tested for caffeine concentration measurement, pH level determination, and organoleptic tests before being ground for analysis. Data were analyzed using the trial version of Minitab® 20.3 (64-bit). This study found that the addition of L. bulgaricus and sprout extract to fermented coffee significantly altered its pH and caffeine content. The addition of L. bulgaricus and longer fermentation can reduce these levels. In addition, the economic analysis results showed that the fermentation process using a fermenter and oven drying resulted in an Investment Rate calculation of 50.10 %, a Break-Even Point of 39.61 %, and an interest rate (i) of 0.0089%.