Gas chromatography-olfactometry

Fig. 3. (a) Flame ionization detector (fid) response to an extract of commercially processed Valencia orange juice, (b) Gas chromatography—olfactometry (geo) chromatogram of the same extract. The abscissa in both chromatograms is a normal paraffin retention index scale ranging between hexane and octadecane (Kovats index). Dilution value in the geo is the -fold that the extract had to be diluted until odor was no longer detectable at each index. 

A relatively new methodology caEed aroma dEution analysis (ada), which combines aroma dEution and gas chromatography-olfactometry to gain a better understanding of the relative importance of aroma compounds, was recently done for coffee. In a roasted Colombian coffee brew, 41 impact compounds were found with flavor dEution threshold factors (FD) greater than 25, and 26 compounds had FD factors of 100 or above. WhEe the technique permits assessment of the impact of individual compounds, it does not evaluate synergistic effects among compounds (13). 

FD-MS, FDMS Field desorption mass spectrometry GCO Gas chromatography-olfactometry... 

Maas B, Dietrich A, Mosandl A, Enantioselective capillary gas chromatography — Olfactometry in essential oil analysis, Naturwissenschafien 80 470 72,1993. 

Priser, C., Etievant, P. X., Nicklaus, S., and Brun, O. (1997). Representative champagne wine extracts for gas chromatography olfactometry analysis. /. Agric. Food Client. 45,3511-3514. 

Mistry, B.S., Reineccius, T., Olson, L.K. (1997) Gas chromatography olfactometry for the determination of key odorants in foods. In Marsili R (ed) Techniques for Analysing Food Aroma. Dekker, New York, pp 265-292. 

Eyres, G., Dufour, J.P> Hallifax, G., Sotheeswaran, S., Marriott, P.J. (2005) Identification of character-impact odorants in Coriander and wild coriander leaves using gas chromatography-olfactometry (GCO) and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-TOFMS). J. Sep. Sci. 28 1061-1074. 

The aroma of foods is caused by volatile compounds which are perceived by the human nose. Many studies (reviews in [1, 2]) have indicated that only a small fraction of the hundreds of volatiles occurring in a food sample contribute to its aroma. To detect these compounds, a method proposed by Fuller et al. [3] is used. In this procedure, which is designated gas chromatography-olfactometry (GC-O), the effluent from a gas chromatography column is sniffed by an expert who marks in the chromatogram each position at which an odour impression is perceived. 

The extract volume at which the odorant was most (AECA) or least (AEDA) perceived by gas chromatography-olfactometry... 

Table 16.5 Gas chromatography-olfactometry of static headspace samples of parsley leaves [31] ...

Audouin V, Bonnet F, Vickers ZM Reineccius G (2001) In Leland JV, Schieberle P, Buettner A, Acree TE (eds) Gas Chromatography-Olfactometry. The State of the Art. ACS Symposium Series 782. American Chemical Society, Washington, p 156... 

Maas, B., A. Dietrich, and A. Mosandl, Enantioselective Capillary Gas Chromatography— Olfactometry in Essential Oil Analysis. Naturwissenschaften, 1993 80, 470-472. 

G1.6 Solid-Phase Microextraction for Flavor Analysis G1.7 Simulation of Mouth Conditions for Flavor Analysis G1.8 Gas Chromatography/Olfactometry... 

Gas Chromatography-Olfactometry (GC-O) Alternate Protocol 2 Sensory Discrimination of Chiral Flavor Compounds Gl.4.8... 

Basic Protocol 1 Gas Chromatography/Olfactometry Using Direct Sniffing Gl.8.1 Basic Protocol 2 Dilution Analysis With Gas Chromatography/... 

Deibler, K.D. 1999. Gas chromatography - olfactometry (GC/O) of vapor phases. In Flavor Chemistry Thirty Years of Progress (R. Ter-anishi, E.L. Wick, and I. Homstein, eds.) pp. 387-395. Kluwer Academic/Plenum Publishers, New York. 

Milo, C. and Grosch, W. 1995. Detection of odor defects in boiled cod and trout by gas chromatography-olfactometry of headspace samples. J. Agric. Food Chem. 43 459-462. 

Enantioselective gas chromatography can provide three quite different kinds of information (1) the amount of each enantiomer present in a food, determined as the enantiomeric purity or the enantiomer excess, and the separation factor a for each pair of enantiomers (2) enantiospecific sensory evaluation using gas chromatography-olfactometry (GC-O) and (3) data used as part of an authenticity determination. 

SENSORY DISCRIMINATION OF CHIRAL FLAVOR COMPOUNDS USING GAS CHROMATOGRAPHY-OLFACTOMETRY (GC-O)... 

Acree, T.E. and Am, H. Flavomet. 1997. Gas chromatography-olfactometry of natural products. http //www.nysaes.comell.edu/fst/faculty/acree /flavomet/index.html. 

Gas chromatography/olfactometry (GC/O) based on dilution analysis (e.g., CharmAna-lysis or Aroma Extraction Dilution Analysis) gives an indication of what compounds are most potent in the aroma of foods. The application of SPME to GC/O dilution analysis can be achieved by varying the thickness of the fiber phase and the length of exposure, resulting in various absorbant volumes. 

Acree, T.E. and Barnard, J. 1994. Gas chromatography—olfactometry and CharmAnalysis. In Trends in Flavour Research (H. Maarse and D.G. van der Heij, eds.) pp. 211-220. Elsevier Science Publishing, New York. 

Evaluate collected sample, e.g., by gas chromatography/olfactometry (GC/O Acree, 1997) or gas chromatography/mass spectrometry (GC/MS). 

It should be kept in mind that most analytical instruments, such as gas chromatographs and mass spectrometers, do not discriminate between volatile compounds that do or do not possess odor activity. Some form of sensory analysis must be conducted in order to select which volatile compounds contribute to the flavor of the foods. Gas chromatography-olfactometry (GC/O) is an important tool to accomplish that task. 

Roberts, D.D. and Acree, T.E. 1996a. Effects of heating and cream addition on fresh raspberry aroma using a retronasal aroma simulator and gas chromatography olfactometry. 7. Agric. Food Chem. 44 3919-3925. 

Leland, J. V., Schieberle, P., Buettner, A., and Acree, T.E. 2001. Advances in gas chromatography-olfactometry. American Chemical Society (ACS) Symposium Series 782. ACS, Washington, D.C. 

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