Analysis of Volatile and Nonvolatile Compounds in Decaffeinated and Regular Coffee Prepared Under Various Roasting Conditions

Abstract

This study investigated the decaffeination effect on the flavor compounds of green and roasted coffee beans. Regular and decaffeinated green beans from Guatemala, Brazil, Ethiopia, and Colombia were prepared under light, medium, and dark roasting conditions. Analysis of the decaffeination-induced changes in nonvolatile compounds revealed that decaffeinated green coffee beans had higher concentrations of trigonelline and total carbohydrates but a lower chlorogenic acid content than regular green coffee beans (both p < 0.05). Flavor differences between regular and decaffeinated coffee were investigated by analysis of the volatile and nonvolatile compounds in roasted coffee beans. From the odor impact ratio values, 3-ethyl-2,5-dimethyl pyrazine, 5-methyl furfural, and guaiacol were primarily responsible for coffee flavor. 3-Ethyl-2,5-dimethyl pyrazine had an average 58% lower concentration in decaffeinated coffee than in regular coffee, a larger difference than any other compound. In conclusion, the decaffeination process may result in flavor differences, such as pyrazine deficiency.

Keywords: Decaffeinated coffee, Water-decaffeination, Chemical composition, flavor