A Caffeine and Chlorogenic acids Concentrations and Organoleptic Test of Robusta Beans (Coffea canephora) Fermented with Microbial Starters

Abstract

Robusta beans contain higher caffeine and chlorogenic acids than Arabica beans. Caffeine and chlorogenic acids were responsible for bitter flavor of brewed coffee. Microbes could modify caffeine and chlorogenic acids concentrations of coffee beans. The purpose of this study were to determine caffeine and chlorogenic acids concentrations of Robusta beans fermented with commercial microbial starters, i.e. tape, bread and tempeh starters and to determine of respondents' preference for their Robusta brewed coffee. Tugusari variety of Robusta beans were fermented aerobically with tempeh starters and anaerobically with tape and bread starters at 28°C for 6 days. Spectrophotometer analysis of caffeine and chlorogenic acids concentrations were carried out on fermented samples and unfermented samples. Brewed coffee of 6^th day fermentation and without fermentation beans were tested organoleptically, include scores for color, aroma, viscosity, acidity, sweetness, bitterness and overall flavors. The highest decrease in caffeine and chlorogenic acids concentrations were obtained from Robusta beans fermented with tempeh starters. Respondents preferred the overall flavors of brewed coffee from Robusta beans fermented with bread and tempeh starters compared to Robusta beans without starters fermentation. Bread starters fermentation on Robusta beans produced the most fragrant aroma of brewed coffee, while tempeh starters fermentation on Robusta beans produced the least bitterness of brewed coffee.