title: Detection of coffee flavour ageing by solid-phase microextraction/surface acoustic wave sensor array technique (SPME/SAW).
abstract: The use of polymer coated surface acoustic wave (SAW) sensor arrays is a very promising technique for highly sensitive and selective detection of volatile organic compounds (VOCs). We present new developments to achieve a low cost sensor setup with a sampling method enabling the highly reproducible detection of volatiles even in the ppb range. Since the VOCs of coffee are well known by gas chromatography (GC) research studies, the new sensor array was tested for an easy assessable objective: coffee ageing during storage. As reference method these changes were traced with a standard GC/FID set-up, accompanied by sensory panellists. The evaluation of GC data showed a non-linear characteristic for single compound concentrations as well as for total peak area values, disabling prediction of the coffee age. In contrast, the new SAW sensor array demonstrates a linear dependency, i.e. being capable to show a dependency between volatile concentration and storage time.
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute for Microstructure Technology (IMT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Barié
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), 57392 Schmallenberg, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Bücking
authors.affiliation: Facultad de Ingeniería Química, Universidad Central del Ecuador, Quito, Ecuador.
authors.forename: Ullrich
authors.initials: U
authors.lastname: Stahl
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute for Microstructure Technology (IMT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. Electronic address: michael.rapp@kit.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Rapp
mesh_terms: D001557:Benzenesulfonates; D002849:Chromatography, Gas / Q000379:methods*; D003069:Coffee / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D052617:Solid Phase Microextraction / Q000379:methods*; D055549:Volatile Organic Compounds
chemical_list: D001557:Benzenesulfonates; D003069:Coffee; D055549:Volatile Organic Compounds; C056082:4-sulfophenylmethallyl ether
keywords: Coffee ageing; Flavour; SAW; Sensors