CHARACTERIZATION OF GREEN AND ROASTED COFFEES THROUGH THE CHLOROGENIC ACID FRACTION BY HPLC-UV AND PRINCIPAL COMPONENT ANALYSIS

摘要

Chlorogenic acids (CGA) are a group of phenolic acid derivatives which are commonly found and differently distributed in higher plants. The CGA pattern can successfully be employed to characterize green and roasted coffees of different origins and qualities. This paper reports on the possibilities of characterizing green or roasted coffees by the CGA fraction through HPLC-W and principal component analysis (PCA) and comparing the results with those from sensory evaluation. The CGA fraction was prepared by submitting the Melitta extracts of green and roasted coffees to cleanup on a C-18 cartridge, and the 40/60 methanol/water fraction was then analyzed by a RP-C-18 column at 325 nm using a methanol/citrate-hydrochloric acid mobile phase in gradient elution. Examples concern the discrimination of coffees of the same quality but from different origins or plantations, discrimination of coffee blends of different compositions, and comparison with sensory evaluation.