Flavour analysis

Figure 10.4 shows a schematic representation of the multidimensional GC-IRMS System developed by Nitz et al. (27). The performance of this system is demonstrated with an application from the field of flavour analysis. A Siemens SiChromat 2-8 double-oven gas chromatograph equipped with two FIDs, a live-T switching device and two capillary columns was coupled on-line with a triple-collector (masses 44,45 and 46) isotope ratio mass spectrometer via a high efficiency combustion furnace. The column eluate could be directed either to FID3 or to the MS by means of a modified Deans switching system . 

Complex flavour analysis with the ion trap detector. Finnigan MAT Application Data Sheet ADS 7. 

Greule, M., Mosandl, A., Kreck, M. and Dietrich, H. (2005) Quality assessment of celeriac juices using enan-tioselective flavour analysis. Deutsche Lebensmittel Rundschau 1 01 (5), 1 99-204. 

Brinkmann H. W., Copier H., De Leuw J. J. M., Tjan S. B. (1972). Components contribution to beef flavour Analysis of the headspace volatiles of beef broth. J. Agric. Food Chem., 20, 177-181. 

SPME can also be used to extract target analytes from food and drug samples. Thus, it has been employed for the extraction of caffeine from coffee and tea [225], and for that of volatile impurities in drugs. Headspace SPME has also been tested for flavour analysis in foods. Thus, the SPME/GC/TOF-MS tandem was successfully used for the rapid analysis of volatile flavour compounds in apple fruit. The sample (300-450 g of apple) was subjected to static headspace sampling for 4 6 h in order to allow the volatiles... 

Ulrich, D., Hoberg, E., Rapp A. and Sandke, G. (1997) Flavour analysis in plant breeding - solid phase micro extraction of strawberry aroma compounds, in H.-P. Kruise and M. Rothe (Eds) Proceed. 5th Wartburg Aroma Symp., Eisenach (Germany), Eigenverlag Univ., Postdam. 

Apart from the sample material the following capillary columns (stationary phases) are suitable for flavour analysis ... 

A relatively new and modern analytical method in flavour analysis is the GC-FTIR-coupling technique. This method together with GC-MS-coupling represents the most sophisticated and flexible analytical technique with respect to the quality and the quantity of information. 

Demyttenaere, J.C.R., Dagher, C., Verhe, R., Sandra, R, Flavour analysis of Greek white wine using solid phase microextraction-capillary GC/MS, in Flavour Research at the Dawn of the Twenty-first Century, Rroceedings of the 10th Weurman Flavour Research Symposium Beaune, Le Quere, J.L., fitievant, R.X. (Eds.), London/Raris/New York, Lavoisier and Intercept 2003... 

First success in enantioselective flavouring analysis was achieved by chromatographic separations of diastereomeric derivatives. In spite of limited sensitivity and frequently laborious work-up conditions, these methods revealed reliable insight into enantiomeric distribution of y(5) lactones and other chiral fruit flavouring compounds, as reviewed previously [55]. 

Shankaranarayana M.L., Abraham K.O., Raghavan B. and Natarajan C.P. (1975) Infrared identification of compounds separated by gas and thin layer chromatography Applications to flavour analysis. CRC Crit. Rev. Food Technol. 6, 271-314. 

It is to be noted that carbon dioxide, one of the most favoured supercritical fluids, is also one of the few gases that are not rotationally active. It is used for the extraction of volatile components in aroma and flavour analysis, a subject area where stereo- and conformational isomerism in the gas phase really is of interest A supercritical fluid eluate could be passed without problem directly into a MMW cavity spectrometer carrying the aroma or other component with it, to achieve stereo- and conformation specific measurements on smaller (<200 Dalton) molecules. 

In the food industry, the determination of key odorants in highly complex extracts is a common analytical challenge. Both the suitability of GCxGC-ToF MS and the inadequacy of GC-ToF MS in target flavour analysis were shown by Adahchour et al. [24]. Two odour-impact compounds, methional and sotolon, were identified and quantified in a very complex dairy spread extract by using the three-dimensional approach. In contrast, GC-ToF MS failed in the isolation of these two minor compounds from high-concentration interferences. 

In GC, the mobile phase or carrier phase is an inert gas such as helium and the stationary phase is a very thin layer of liquid or polymer on an inert solid support inside a column. The volatile analytes interact with the walls of the column, and are eluted based on the temperature of the column at specific retention times (Grob Barry, 2004). The eluted compoimds are identified with detectors. Flame ionization and mass spectrometry are the most commonly used detectors for flavour analysis (Vas Vekey, 2004). 

Raes, K., Balcaen, A., Dirinck, P., De Winne, A., Claeys, E., Demeyer, D., et al. (2003). Meat quaUty, fatty acid composition and flavour analysis in Belgian retail beef. Meat Science, 65,1237-1246. 

Zabetakis, I., Holden, M. A. (1997). Strawberry flavour analysis and biosynthesis. Journal of the Science of Food Agriculture, 74, 421-434. 

R196 P. J. Marriott, G. T. Eyres and J.-P. Dufour, Opportunities for Flavour Analysis through Hyphenation , in Expression of Multidisciplinary Flavour Science, Proceedings of the Weurman Symposium, 12, Interlaken, Switzerland, July 1-4, 2008, [online computer file], eds. I. Blank, M. Wuest and C. Yeretzian, Zuercher Hochschule fuer Angewandte Wissenschaften, Institut fuer Chemie und Biologische Chemie, Waedenswil, Germany, 2008, Pub. 2010, p. 505. 

Methods for the study of grape flavour have often been employed in flavour analysis of other fruits and beverages. Techniques such as solvent extraction (Cacho et al. 1992) or headspace methods (Kallio 1991) may be used to isolate volatiles, and analysis usually involves gas-liquid chromatography (Cronin 1982), coupled with mass spectrometry (Merritt and Robertson 1982). Such methods have provided qualitative and some quantitative assessment of grape aroma composition, usually as part of research on wine flavour (Strauss et al. 1986 Rapp 1988 Eti vant 1991). 

Schreier, P., The use of HRGC-FTIR in tropical fruit flavour analysis, in Analysis of Volatiles Methods and Applications, P. Schreier, Ed., de Gruyter, Berhn, 1984, p. 269. 

Fay, L.B. Yeretzian, C. Blank, 1. Novel Mass Spectrometry Methods in Flavour Analysis. Chimia 2001, 55,429-434. 

Special focus has been set to the widely used and popular sample preparation methods as there are the pressurized liquid extraction (RLE), the thermal extraction of materials and food (outgassing), and in detail on the QuEChERS pesticide sample preparation used for GC-MS and LC-MS. As a consequence of the higher matrix load of these extracts and the recommended GC injection techniques, concurrent backflush, preventive maintenance and inlet deactivation became current topics of discussion. Olfactometry solutions have been added for apphcations in flavour analysis. 

LB Fay, C Yeretzian, I Blank. Novel mass spectrometry methods in flavour analysis. Chimia 55 429-434, 2001. 

R Teranishi. Challenges in flavour chemistry An overview. In CJ Mussinan, MJ Morello, eds. Flavour Analysis Developments in Isolation and Characterization. Washington, DC American Chemical Society, 1998, pp 1-6. 

Jublot, L. (2011) Pushing boundaries of flavour analysis with GC x GC-TOFMS and PTR-MS. New Food 14,19. 

H. Sugisawa, Prerequisites for sample preparation in flavour analysis. Analysis of Volatiles (P. Schreier, ed.), Walter de Gruyter, Berlin, New York, 1984, p. 3. 

K. Gassenmeier, Thermodesorption in flavour analysis. Frontiers of Flavour Science (P. Schieberle and K. H. Engel, eds.), WB-Druck GmbH, Rieden am Forg-gensee, 2000, p. 135. 

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