Volatile Organic Compounds in Brewed Kenyan Arabica Coffee Genotypes by Solid Phase Extraction Gas Chromatography Mass Spectrometry

Abstract

Besides its stimulatory effect, coffee is appreciated and/or consumed for its pleasing aroma, which is a key quality index. The objective of this study was to characterize the volatile organic compounds in brewed Kenyan Arabica coffee genotypes. Solid phase Extraction (SPE) technique was used for the extraction of the organic compounds in the brewed coffee, while characterization of the compounds was done by gas chromatography mass spectrometry (GC-MS). Various volatile organic compounds were identified and classified into alcohols, aldehydes, carboxylic acids, furans, ketones, pyrazines and pyrroles. Differences were observed in the chromatographic profiles of the eluents from the seven coffee genotypes evaluated. Compounds such as 2, 6-dimethylpyrazine,5-methyl-1H-pyrole-2-carboxyaldehyde,2-furanmethanolacetate, 4-Ethylcatechol, Methoxy-4-vinylphenol, 2,6-Dihydroxyacetophenone and Ionone, were found to be present in all the coffee genotypes. This study demonstrated the presence of appreciable levels of volatile organic compounds in the coffee brew of the genotypes studied with variations in the types and concentrations being observed among the genotypes.

Keywords: Kenya, Coffee genotypes, Solid Phase Extraction (SPE), Gas Chromatography Mass Spectrometry (GC-MS) Volatile organic compounds.