Changes in the Quinic Acid Contents of Coffee Beans in the Process of Roasting

Abstract

By using silica gel column chromatography, the amounts of malic, citric, tartaric and quinic acids of green and roasted coffee beans were determined. Among these acids, the average quinic acid content was as follows: green beans 1.31%, medium roast 1.38%, French roast 0.47%, ice roast 2.08% and Italian roast 1.67%. In the course of roast, the quinic acid content increased slightly during medium roasting and then decreased rapidly by the the thermal decomposition. But a remarkable increase was observed after French roasting. From this fact, it can be concluded that after French roasting, quinic acid is liberated from brown pigments, which are produced by the thermal reaction of sucrose and chlorogenic acids.