ORCID Profile
0000-0002-6205-5125
Current Organisations
Fraunhofer Institute for Process Engineering and Packaging
,
Friedrich-Alexander-Universität Erlangen-Nürnberg
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Publisher: Elsevier BV
Date: 04-2014
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.FOODCHEM.2016.03.110
Abstract: Botrytis cinerea and Erysiphe necator are among the most relevant fungi in viticulture. In order to deepen our knowledge about their potential impact on wine quality, their effects on the aroma character of the initial stage of wine production, i.e. the must were studied. The main aroma compounds were determined by gas chromatography-olfactometry (GC-O) and ranked according to their relative intensities by means of aroma extract dilution analysis (AEDA). Clear differences between healthy and infected s les were observed. Botrytis cinerea had a positive impact on fruity and floral notes while several earthy smelling compounds were developed as result of the infection. Unlike in previous studies, however, we did not observe any clear differences in the quantities of earthy-mushroom-like smelling substances as result of the infection process with Erysiphe necator.
Publisher: Walter de Gruyter GmbH
Date: 06-02-2018
Abstract: GABA A receptors are ligand-gated anion channels that form pentameric arrangements of various subunits. Positive allosteric modulators of GABA A receptors have been reported as being isolated either from plants or synthesized analogs of known GABA A receptor targeting drugs. Recently, we identified monoterpenes, e.g. myrtenol as a positive allosteric modulator at α1β2 GABA A receptors. Here, along with pharmacophore-based virtual screening studies, we demonstrate that scaffold modifications of myrtenol resulted in the loss of modulatory activity. Two independent approaches, fluorescence-based compound analysis and electrophysiological recordings in whole-cell configurations were used for analysis of transfected cells. C-atoms 1 and 2 of the myrtenol backbone were identified as crucial to preserve positive allosteric potential. A modification at C-atom 2 and lack of the hydroxyl group at C-atom 1 exhibited significantly reduced GABAergic currents at α1β2, α1β2γ, α2β3, α2β3γ and α4β3δ receptors. This effect was independent of the γ2 subunit. A sub-screen with side chain length and volume differences at the C-atom 1 identified two compounds that inhibited GABAergic responses but without receptor subtype specificity. Our combined approach of pharmacophore-based virtual screening and functional readouts reveals that side chain modifications of the bridged six-membered ring structure of myrtenol are crucial for its modulatory potential at GABA A receptors.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.FOODCHEM.2013.02.043
Abstract: The relationship between emulsion structure and the release of volatile organic compounds (VOCs) was investigated using a model mouth system under oral conditions (tongue mastication, artificial saliva, pH and salt). The VOCs were monitored on-line by proton transfer reaction mass spectrometry (PTR-MS). Two types of emulsion system were compared: primary and multilayer oil-in-water (P-O/W, M-O/W) emulsions consisting of soy oil coated by β-lactoglobulin and pectin layers. The P-O/W emulsions showed intensive flocculation at pH 5 and above 200 mM NaCl where the electrostatic repulsive charge was at a minimum. Bridging and depletion flocculation were mostly observed for P-O/W emulsions containing artificial saliva with 1 wt% mucin. The VOC release was found to increase when the emulsion droplets flocculated, thus changing the oil volume phase distribution. The adsorbed pectin layer stabilised the emulsion structure under conditions of short-time oral processing, and hindered the release of hydrophobic VOCs.
Publisher: Wiley
Date: 11-09-2014
Abstract: The emulsifying properties of plant legume protein isolates (soy, pea, and lupin) were compared to a milk whey protein, β-lactoglobulin (β-lg), and a nonionic surfactant (Tween 20). The protein fractional composition was characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The following emulsion properties were measured: particle diameter, shear surface ζ-potential, interfacial tension (IT), and creaming velocity. The effect of protein preheat treatment (90 °C for 10 min) on the emulsifying behavior and the release of selected volatile organic compounds (VOCs) from emulsions under oral conditions was also investigated in real time using proton transfer reaction-mass spectrometry. The legume proteins showed comparable results to β-lg and Tween 20, forming stable, negatively charged emulsions with particle diameter d3,2 < 0.4 μm, and maintained stability over 50 d. The relatively lower stability of lupin emulsions was significantly correlated with the low protein surface hydrophobicity and IT of the emulsion. After heating the proteins, the droplet size of pea and lupin emulsions decreased. The VOC release profile was similar between the protein-stabilized emulsions, and greater retention was observed for Tween 20-stabilized emulsions. This study demonstrates the potential application of legume proteins as alternative emulsifiers to milk proteins in emulsion products.
Publisher: American Chemical Society (ACS)
Date: 20-09-2012
DOI: 10.1021/JF3028232
Abstract: The release of volatile organic compounds (VOCs) into the mouth cavity is an integral part of the way flavor is perceived. An in vitro model mouth with an artificial tongue was developed to measure the dynamic release of VOCs from liquid model systems [e.g., aqueous solution, oil, and oil-in-water (O/W) emulsions] under oral conditions. The release of seven selected VOCs was affected by the different polarity and vapor pressure of the compounds and their affinity to the liquid system media. Different tongue pressure patterns were applied to the liquid systems, and the release of VOCs was monitored in real time using proton transfer reaction-mass spectrometry. The release was significantly more intense for longer tongue pressure duration and was influenced by the tongue altering the s le surface area and the distribution of the VOCs. The role of saliva (artificial versus human) and the s le temperature had a significant effect on VOC release. Saliva containing mucin and a higher s le temperature enhanced the release.
Location: Germany
Location: Germany
No related grants have been discovered for Andrea Buettner.