Effect of kombucha culture on caffeine and chlorogenic acid content in fermentation of robusta green coffee beans (Coffea canephora l.)

Abstract

Caffeine and chlorogenic acid are two substances that are usually contained in coffee as a stimulant and an antioxidant. Green coffee has been reported to contain higher amounts of caffeine and chlorogenic acid compared to black coffee. In Indonesia, green coffee highly produced in Garut, Soreang, Ciwidey, and Aceh. The purpose of this research is to determine the content of caffeine and chlorogenic acid and acidity (pH) from Robusta green coffee beans, by adding kombucha culture at 0, 6, 12 and 18 days of their fermentation. The analysis of pH was carried out using a pH meter, while caffeine and chlorogenic acid were carried out using High-Performance Liquid Chromatography (HPLC). The results showed a decrease in pH in Garut, Soreang, Aceh and Ciwidey green coffee beans, the pHs obtained on the 18th day were 65.33; 66.67; 64.00; 64.86 % respectively, and the content of caffeine decreasing concentration at the 18th day were 34.47; 39.06; 36.93 and 35.69 % respectively, while the highest contents of chlorogenic acid increasing concentration on the 18th day were 13.17; 10.15; 14.02 and 11.13 %, respectively. We also recommended testing the fermentation of Arabica green coffee beans to obtain a comparison of the results of Robusta coffee beans.