Analysis of hydroxycinnamic acids of coffee: A comparison of high performance liquid chromatography and capillary zone electrophoresis

The purpose of this work was to evaluate the heat degradation of hydroxycin namic acids (HCAs) present in coffee by CZE and HPLC. The HCAs were obtaine d by alkaline hydrolysis of a coffee sample Coffea canephora var. robusta, heated at programmed temperatures and constant time, previously fixed with the limits of industrial roasting. The thermal degradation rate of each aci d could apparently be explained by its specific sensitivity, which is corre lated with its chemical structure. 3,4,5-Trimethoxycinnamic acid was the mo st resistant and caffeic acid the most sensitive of all analyzed HCAs. This study suggests that CZE, while lacking the versatility of HPLC, may be regarded as a complementary analytical technique for the evaluation of hea t degradation of these compounds.