Aroma identification

Smyth, H., Cozzolino, D., Herderich, M. J., Sefton, M. A., Francis, 1. L. (2005) Relating volatile composition to wine aroma Identification of key aroma compounds in Australian white wines. In R. J Blair, P. J. Williams, I. S. Pretoiius (Eds.), Proceedings of the Twelfth Australian Wine Industry Technical Conference, Melbourne, Australia (pp. 31-33). Australian Wine Industry Technical Conference Inc. Adelaide, SA. 

Nanto H., Kawai T., Sokooshi H. and Usuda T. (1993) Aroma identification using a quartz-resonator sensor in conjunction with pattern recognition. Sens. Actuators B14(l-3), 718-20. 

GC-O of the SDE-SV extract of a commercial meaty/savory flavoring (sample C, Table 6) revealed 15 odor-active components out of about 100 volatiles. However, only six odorants showed ED factors of 2 and higher (Table 7). The meaty/savory note was mainly imparted by odorants containing sulfur. The c -isomer of 2-methyl-3-tetrahydrofuranthiol was also found, but did not contribute to the overall aroma. Identification was mainly based on GC-MS and NMR and was verified by commercially available or synthesized reference compounds. These are essential for unequivocal identification. The chemical structures of the aroma impact compounds identified in the flavoring are shown in Fig. 12. 

Day EA, Anderson DF. 1965. Gas chromatographic and mass spectral identification of natural components of the aroma fraction of blue cheese. J Agric Food Chem 13 2-4. 

In each of these situations, sensing the aroma, which, for the purposes of this book, we will consider to consist of a specific molecule or suite of molecules that is uniquely produced by its source, provides the means of identification and/or location of the source. In each of these examples the user would gain significant advantage if a very sensitive and specifically tuned electronic sensor, which could accurately and reliably identify the characteristic aroma for that application, were available. 

For all of recorded history mankind has located and identified certain items by their aroma. Whether it is a dead mouse in the closet or a freshly baking loaf of bread in the oven, we often make the identification correctly without seeing or touching the item. We have considered this sense so useful that when we find our own sense of smell to have inadequate sensitivity for a certain task we often borrow the more acute sense of smell from some animal. For centuries we have used dogs for hunting and pigs for truffle harvesting. 

Harada, N., N. Okazaki, Y. Kizaki, and S. Kobayashi. Identification and distribution of an aroma component in rice. Nippon Jozo Kyokaishi 1990 85(5) 350-352. 

Nishimura, O. Identification of the characteristic odorants in fresh rhizomes of ginger (Zingiber officinale Roscoe) using aroma extract dilution analysis and modified multidimensional gas chromatography-mass spectroscopy. J Agr Food Chem 1995 43(11) 2941-2945. 

Silva Ferreira, A. C., Hogg, T., and Guedes de Pinho, P. (2003). Identification of key odorants related to the typical aroma of oxidation-spoiled white wines. /. Agric. Food Chem. 51, 1377-1381. 

Sampling and Analysis. A frozen slice of bread was cut in pieces and stacked in an enlarged sample flask of an aroma isolation apparatus according to MacLeod and Ames (74). Volatile compounds were trapped on Tenax TA and afterwards thermally desorbed and cold trap injected in a Carlo Erba GC 6000 vega equipped with a Supelcowax 10 capillary column (60 m x 0.25 mm i.d.) and a flame ionisation detector. Similar GC conditions were used for GC-MS identification of volatile compounds by dr. M.A. Posthumus (Dept. Organic Chemistry, VG MM7070F mass spectrometer at 70 eV El, 75). 

H. Maarse, R. Belz, Isolation, Separation and Identification of Volatile Compounds in Aroma Research, Akademie-Verlag, Berlin 1981. 

Volatile constituents of cupuacu were isolated by steam distillation-extraction of pulp or juice [2].The identification of volatile constituents was based on mass spectral analysis. The pleasant aroma compounds were mainly esters (Fig. 8.2). Targe amounts of ethyl butanoate and small amounts of ethyl acetate, butyl acetate, and butyl isobutanoate were described. 

Reviews published by Acree and Teranishi [7], Blank [8], Grosch [1, 2, 9], Mistry et al. [10] and Schieberle [11] agree that GC-O was the starting point for the development of a systematic approach for the identification of the compounds causing food aromas. The aim of this chapter is to discuss the potential and the limitations of GC-O. 

G1.3 Identification and Quantitation of Aroma Compounds Basic Protocol Identification (GC-FID GC-MS) and Quantification of Gl.3.1... 

Aroma compounds are present in minute levels in foods, often at the ppb level ( ig/liter). In order to analyze compounds at these levels, isolation and concentration techniques are needed. However, isolation of aroma compounds from a food matrix, which contains proteins, fats, and carbohydrates, is not always simple. For foods without fat, solvent extraction (unit gu) can be used. In foods containing fat, simultaneous distillation extraction (SDE see Basic Protocol 1) provides an excellent option. Concentration of headspace gases onto volatile traps allows sampling of the headspace in order to obtain sufficient material for identification of more volatile compounds. A separate protocol (see Basic Protocol 2) shows how volatile traps can be used and then desorbed thermally directly onto a GC column. For both protocols, the subsequent separation by GC and identification by appropriate detectors is described in unitgu. 

Freitas, V., Ramalho, P., Azevedo, Z., and Macedo, A. (1999). Identification of some volatile descriptors of the rock-rose like aroma of fortified red wines from Douro Demarcated Region. ]. Agric. Food Chem. 47, 4327-4331. 

Miklosy, E., Kalmar, Z., and Kerenyi, Z. (2004). Identification of some characteristic aroma compounds in noble rotted grape berries and aszu wines from Tokaj by GC-MS. Acta Aliment. Hung. 3,215-226. 

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