The preparation of a cup of coffee may vary between countries, cultures and individuals. Here, an analysis of nine different extraction methods is presented regarding analytical and sensory aspects for four espressi and five lunghi. This comprised espresso and lungo from a semi-automatic coffee machine, espresso and lungo from a fully automatic coffee machine, espresso from a singleserve capsule system, mocha made with a percolator, lungo prepared with French Press extraction, filter coffee and lungo extracted with a Bayreuth coffee machine. Analytical measurements included headspace analysis with HS SPME GC/MS, acidity (pH), titratable acidity, content of fatty acids, total solids, refractive indices (expressed in°B rix), caffeine and chlorogenic acids content with HPLC. Sensory analysis included visual, aroma, flavor and textural attributes as well as aftersensation. The technical differences in the extraction methods led to a higher concentration of the respective quantities in the espressi than in the lunghi. Regarding the contents per cup of coffee, the lunghi generally had a higher content than the espressi. The extraction efficiency of the respective compounds was mainly driven by their solubility in water. A higher amount of water, as in the extraction of a lungo, generally led to higher extraction efficiency. Comparing analytical data with sensory profiles, the following positive correlations were found total solids $ texture/body, headspace intensity $ aroma intensity, concentrations of caffeine/chlorogenic acids $ bitterness and astringency.

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Photodissociation spectra were determined for Au(m)(+) . Ar(n) (m=7; n=0-3 and m=8,9; n=0,1) in the photon energy range of 2.14-3.02 eV. Experimental data were compared with predictions of dipole allowed transitions using time-dependent density functional theory (TDDFT) as applied to cluster structures from both DFT (B3-LYP functional) and ab initio calculations at the MP2 level. Argon adduct formation does not significantly perturb the bare metal cluster core structure, but it does change the metal cluster spectrum for highly symmetric cluster structures. The photodissociation spectra are consistent with a transition from planar to three-dimensional gold cluster core geometries between m=7 and m=8 for both n=0 and 1. TDDFT predictions for favored isomers describe experimental absorption features to within +/-0.25 eV. We also discuss size-dependent trends in TDDFT transition energies for the lowest energy two- and three-dimensional structures of Au(m)(+)(m=3-9).

A real-time automated process control tool for coffee roasting is presented to consistently and accurately achieve a targeted roast degree. It is based on the online monitoring of volatile organic compounds (VOC) in the off-gas of a drum roaster by proton transfer reaction timeof-flight mass spectrometry at a high time (1 Hz) and mass resolution (5,500 m/Δm at full width at half-maximum) and high sensitivity (better than parts per billion by volume). Forty-two roasting experiments were performed with the drum roaster being operated either on a low, medium or high hot-air inlet temperature (= energy input) and the coffee (Arabica from Antigua, Guatemala) being roasted to low, medium or dark roast degrees. A principal component analysis (PCA) discriminated, for each one of the three hotair inlet temperatures, the roast degree with a resolution of better than ±1 Colorette. The 3D space of the three first principal components was defined based on 23 mass spectral profiles of VOCs and their roast degree at the end point of roasting. This provided a very detailed picture of the evolution of the roasting process and allowed establishment of a predictive model that projects the onlinemonitored VOC profile of the roaster off-gas in real time onto the PCA space defined by the calibration process and, ultimately, to control the coffee roasting process so as to achieve a target roast degree and a consistent roasting.

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