Effect of decaffeination and re-fermentation on level of caffeine, chlorogenic acid and total acid in green bean robusta coffee

Abstract

Caffeine, chlorogenic acid, and total acid are important compounds affecting the taste of coffee. The purpose of this study is to determine the effect of decaffeination and re-fermentation on levels of caffeine, chlorogenic acid, and total acid in green beans of robusta coffee. This study consisted of several treatments, namely: green beans without treatment, green beans re-fermentation without decaffeination, decaffeinated green beans without fermentation, and decaffeinated green beans of coffee by re-fermentation with the addition of mucilage analogs. The decaffeination process used the Swiss Water Process (SWP) method, and re-fermentation used a mucilage analog of the blend of purple sweet potato and passion fruit pulp. The caffeine and chlorogenic acid content were determined using UV-VIS spectrophotometry, and total acid was determined using acid-base titration methods. The results were showed that the decaffeination and re-fermentation processes affected the levels of caffeine, chlorogenic acid, and total acid of green bean coffee. Caffeine concentration ranged from 1.04% (green bean coffee without fermentation treatment) to 2.6% (green beans coffee without treatments). The results of the chlorogenic acid analysis showed that the highest amount of green beans coffee without treatment (2.13%) and the lowest found in advanced fermented green beans coffee without decaffeination (1.07%). According to the result of total acid, the highest total acid was green beans coffee without treatment (0.22%), and the lowest was decaffeinated green beans coffee without fermentation (0.16%).