title: Differentiation of degrees of ripeness of Catuai and Tipica green coffee by chromatographical and statistical techniques.
abstract: The quality of green coffee is influenced by the degree of ripeness of the fruit at harvest. The aim of this study was to identify chemical markers differentiating between degrees of ripeness. Two coffee varieties, Catuai and Tipica, from the same farm were analysed using the following parameters and methods: caffeine and chlorogenic acid content using high-performance liquid chromatography (HPLC), sucrose content using hydrophilic interaction chromatography, high-molecular weight fraction (HMW) using high-performance size-exclusion chromatography (HPSEC) and volatile compounds using headspace solid phase micro extraction gas chromatography/mass spectrometry. The best method for differentiating between degrees of ripeness was found to be principal component analysis (PCA) based on HPLC data. HPSEC showed differences in the HMW fraction for different degrees of ripeness and both coffee varieties. Volatile profiles allowed separation of both varieties; yet, except for ripe Catuai, no separation was achieved for the degree of ripeness.
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, Einsiedlerstrasse 31, CH-8820 Wädenswil, Switzerland.
authors.forename: Samo
authors.initials: S
authors.lastname: Smrke
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, Einsiedlerstrasse 31, CH-8820 Wädenswil, Switzerland.
authors.forename: Ivana
authors.initials: I
authors.lastname: Kroslakova
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, Einsiedlerstrasse 31, CH-8820 Wädenswil, Switzerland. Electronic address: alexia.gloess@zhaw.ch.
authors.forename: Alexia N
authors.initials: AN
authors.lastname: Gloess
authors.affiliation: Zurich University of Applied Sciences, Institute of Chemistry and Biological Chemistry, Einsiedlerstrasse 31, CH-8820 Wädenswil, Switzerland.
authors.forename: Chahan
authors.initials: C
authors.lastname: Yeretzian
mesh_terms: D002110:Caffeine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003069:Coffee / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*
chemical_list: D003069:Coffee; D002110:Caffeine
keywords: Coffee; Coffee ripeness; Green coffee; HPLC; HS SPME GC/MS; PCA; SEC