Ji Sun Lim  Seung Eun Lee  Seong Jun Kim  Bonggeun Shong  Young-Kwon Park  Hong-shik Lee

10.7464/ksct.2024.30.3.203

Supercritical fluid extraction Decaffeination Trigonelline Chlorogenic acid

This study investigated the optimal conditions for efficiently removing caffeine from green coffee beans using supercritical fluid extraction while preserving the key flavor compounds, trigonelline and chlorogenic acid. The results of the experiments conducted under various pretreatment and supercritical fluid extraction conditions revealed that the highest caffeine extraction rate was 90.6% and it was achieved when green coffee beans with a moisture content of 35% were soaked in hot water. However, this condition also showed a tendency to slightly reduce the retention rates of trigonelline and chlorogenic acid. In the supercritical fluid extraction time experiments, the caffeine content decreased as the extraction time increased. Furthermore, extraction at a temperature of 60 oC and a pressure of 40 MPa was the most effective in terms of both caffeine removal and flavor compound preservation. As the amount of water added increased, the caffeine extraction rates increased, but there was also an increase in the loss of flavor compounds. With an increase in the solvent-to-material ratio, the caffeine removal rates improved. The optimal results were observed at a ratio of 250, which achieved a caffeine extraction rate of 91.0% and retention rates of trigonelline and chlorogenic acid of 99.9% and 85.9%, respectively.