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Scientific Articles - PTR-MS Bibliography

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Found 5 results
Title [ Year(Asc)]
Filters: Author is Beauchamp, J.  [Clear All Filters]
[1563] Silcock, P.., M.. Alothman, E.. Zardin, S.. Heenan, C.. Siefarth, P.J.. Bremer, and J.. Beauchamp, "Microbially induced changes in the volatile constituents of fresh chilled pasteurised milk during storage", Food Packaging and Shelf Life, vol. 2, pp. 81¬タモ90, Dec, 2014.
<p>Off-odours caused by volatile organic compounds (VOCs) are often the first indicators consumers have of milk spoilage. In this study the VOCs associated with three types (trim, 0.25&ndash;0.40% fat; lite, 1.40&ndash;1.50% fat; and full-cream, 3.18&ndash;3.28% fat) of fresh chilled pasteurised milk (FCPM), held for up to 17 days at 4.5 &plusmn; 0.5 &deg;C, were measured using proton-transfer-reaction mass spectrometry (PTR-MS). The chemical identification of VOCs in the headspace of the milk was supported by SPME&ndash;GC&ndash;MS analysis. Bacterial numbers (aerobic plate count at 25 &deg;C) in the milk were also estimated. Replicate sets of milk types treated with sodium azide (NaN3) to inhibit microbial activity were investigated. The relationship between microbial numbers and VOCs was not linear; rather the concentrations of VOCs only started to change after a threshold number of bacteria ranging from 106&ndash;108 CFU mL&minus;1 was reached. This combined approach provided new insights on the effect of microbial growth on FCPM shelf-life.</p>
[Benjamin2013] Benjamin, O.., P.. Silcock, J.. Beauchamp, A.. Buettner, and D.. W. Everett, "Volatile release and structural stability of β-lactoglobulin primary and multilayer emulsions under simulated oral conditions.", Food Chem, vol. 140, no. 1-2: Riddet Institute, Palmerston North, New Zealand., pp. 124–134, Sep, 2013.
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.
[Benjamin2012] Benjamin, O.., P.. Silcock, J.. Beauchamp, A.. Buettner, and D.. W. Everett, "Tongue pressure and oral conditions affect volatile release from liquid systems in a model mouth.", J Agric Food Chem, vol. 60, no. 39: Riddet Institute, Massey University , Palmerston North 4442, New Zealand., pp. 9918–9927, Oct, 2012.
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 sample surface area and the distribution of the VOCs. The role of saliva (artificial versus human) and the sample temperature had a significant effect on VOC release. Saliva containing mucin and a higher sample temperature enhanced the release.
[Beauchamp2010] Beauchamp, J.., F.. Kirsch, and A.. Buettner, "Real-time breath gas analysis for pharmacokinetics: monitoring exhaled breath by on-line proton-transfer-reaction mass spectrometry after ingestion of eucalyptol-containing capsules.", J Breath Res, vol. 4, no. 2: Sensory Analytics, Fraunhofer Institute for Process Engineering and Packaging (IVV), Giggenhauser Str. 35, D-85354 Freising, Germany., pp. 026006, Jun, 2010.
Eucalyptol (1,8-cineole) is a common active agent in non-prescription pharmaceutical products that is employed to clear the airways during mucus blockages. Following ingestion of a eucalyptol-containing capsule, the capsule dissolves in the gut and transfers eucalyptol into the blood, which is subsequently expelled via the lungs, thus exposing this decongesting and inflammation-abating compound to the airways. The breath gas concentrations of eucalyptol in 11 healthy adult volunteers were monitored at regular intervals after capsule ingestion using on-line proton-transfer-reaction mass spectrometry (PTR-MS). Eucalyptol appeared in exhaled breath gas at varying times following ingestion, with its onset ranging from 1 h and 6 min to 4 h and 48 min (mean ± SD: 2.1 ± 0.5 h). Maximum concentrations also varied greatly, with peak eucalyptol levels between 106 and 1589 ppb(v) (mean ± SD: 489 ± 319 ppb(v)). These variations were not only inter-subject, but also intra-subject, i.e. repeated tests with the same participant yielded different onset times and a broad range of concentration maxima. A considerable contribution to these variations from infrequent sampling and analysis is discussed. This study characterized the temporal transfer of eucalyptol via the blood into the airways by examining exhaled breath and thereby demonstrated the suitability of on-line breath gas analyses, particularly PTR-MS, for certain pharmacokinetic investigations.
[Singer2007] Singer, W.., J.. Beauchamp, J.. Herbig, J.. Dunkl, I.. Kohl, and A.. Hansel, "Dynamic Gas Dilution System for Accurate Calibration of Analytical Instruments such as PTR-MS", 3rd International PTR-MS Conference on Proton Transfer Reaction Mass Spectrometry and Its Applications, pp. 232-237, 2007.

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Selected PTR-MS related Reviews

F. Biasioli, C. Yeretzian, F. Gasperi, T. D. Märk: PTR-MS monitoring of VOCs and BVOCs in food science and technology, Trends in Analytical Chemistry 30 (7) (2011).

J. de Gouw, C. Warneke, T. Karl, G. Eerdekens, C. van der Veen, R. Fall: Measurement of Volatile Organic Compounds in the Earth's Atmosphere using Proton-Transfer-Reaction Mass Spectrometry. Mass Spectrometry Reviews, 26 (2007), 223-257.

W. Lindinger, A. Hansel, A. Jordan: Proton-transfer-reaction mass spectrometry (PTR–MS): on-line monitoring of volatile organic compounds at pptv levels, Chem. Soc. Rev. 27 (1998), 347-375.


Lists with PTR-MS relevant publications of the University of Innsbruck can be found here: Atmospheric and indoor air chemistry, IMR, Environmental Physics and Nano-Bio-Physics


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