Analysis of flavor precursors

Application of tandem mass spectrometry for the analysis of flavor precursors... 

The first five chapters of this book focus on the grape derived and varietal flavors of wines. Many of these compounds occur as nonvolatile glycosidic flavor precursors and the separation and analysis of these precursors have been a challenging and active field of research. The isolation and quantification of trace volatiles represent examples of the difficulties faced by flavor chemists as they attempt to characterize varietal flavors with sensory thresholds in the parts per trillion range and lower. 

Ibarz, M.J., Ferreira, V., Hernandez, P., Loscos, N. and Cacho, J. (2006) Optimisation and evaluation of a procedure for the gas chromatographic-mass spectrometric analysis of the aromas generated by fast acid hydrolysis of flavor precursors extracted from grapes,/. Chromatog. A, 1116(1-2), 217-229. 

Schieberle, P. 1995a. New developments in method for analysis of volatile flavor compounds and their precursors. In Characterization of Food Emerging Methods (A.G. Gaonkar, ed.) pp. 403-431. Elsevier Science Publishing, New York. 

New Developments in Methods for Analysis of Volatile Flavor Compounds and their Precursors... 

There are tvo approaches to meat flavor analysis one is concerned vith the isolation and identification of volatile flavor components, and the other involves identification of non volatile flavor precursors. 

P. Schieberle, New Developments on Methods for Analysis of Volatile Flavor Compounds and Their Precursors. In Characterization of Food Emerging Methods A. G. Gaonkar, Ed. Elsevier Amsterdam, 1995 pp 403 33. 

Sefton, M.A., Francis, I.L. Williams, P.J. (1993). The volatile composition of Chardonnay juices. A study by flavor precursors analysis. Am. J. Enol. Vitic., 44, 359-370. 

Recognition of these phenonena in grapes and wines ( ), and the importance therefore of the glycosides as precursors of flavor in those systans 8) has stimulated much research interest in the role of non-volatile flavor precursors in other fruits (9-11), processed fruits (12), and leaf products (13, 14). For convenience this line of investigation is described here as the "precursor analysis approach" to flavor research. 

This paper discusses new developments in this field of research and in particular the application of the precursor analysis approach to the study of flavor conpounds of non-monoterpene containing grape varieties. 

The precursor analysis approach should now be seen as a useful complement to traditional methods of flavor analysis of fruits. The latter methods are often limited to the painstaking processes of isolation and identification of those trace constituents which are directly responsible for flavor. The precursor analysis approach takes advantage of the evidence provided by Nature vhen secondary metabolites, including flavor corpounds, are biochanically transformed and accumulated by the fruit. 

Weenen, H., Tjan, S.B. Analysis, structure, and reactivity of 3-deoxyglucosone. In Flavor precursors thermal and enzymatic conversions, Teranishi, R., Takeoka, G.R., Guentert, M. (Eds.), American Chemical Society, Washington, DC, 1992, 217-231. 

Yaylayan, V. A. and Keyhani, A. 1996. Pyrolysis/GC/MS analysis of non-volatile flavor precursors Amadori compounds. In Contribution of low- and non-volatile materials to the flavor of foods, ed. P. Winterhalter, C.-T. Ho, and A. M. Spanier, 13-26. Carol Stream, IL Allured Publishing. 

Smith (1963a) and Feldman et al. (1969) underlined the importance of non-volatile compounds to the flavor of coffee. The comparison between the composition of green and of roasted coffee showed an important decrease in the content of proteins, chlorogenic acid and sucrose on roasting. Fractionation and analysis of the aroma precursors in green coffee have also been studied by Russwurm (1970) who considers that the non-volatile constituents of green coffee that may be involved in flavor formation are carbohydrates, proteins, peptides and free amino acids, polyamines and tryptamines, lipids, phenolic acids, trigonelline and various non-volatile acids. 

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