Identification in roasted

Frank O., Blumberg S., Kunert C., Zehentbauer G., Hofmann T. Structure determination and sensory analysis of bitter-tasting 4-vinylcatechol oligomers and their identification in roasted coffee by means of LC-MS/MS. Journal of Agricultural and Food Chemistry, 55 1945-1954 (2007). 

In summary, model studies are very efficient for the identification and structure elucidation of important flavor components. Most of the compounds reported here have not been identified in meat and have not yet been reported as constituents of food volatiles. Nevertheless, there are good reasons to believe that minute traces of these sulfur-containing components are present in roasted and/or cooked meat volatiles because our model system was based solely on naturally occurring precursors. We believe that only minute trace amounts of these types of components need to be present in natural products to be of prime significance due to their extremely low odor threshold values. 

The knowledge that not all of the volatiles (e.g. more than 800 in roasted coffee) [5] that occur in a food contribute to its aroma was the rationale for changing the methodology of analysis. Since 1984, when the procedure for charm analysis was published [4], techniques have been developed that focus on the identification of compounds contributing to the aroma with higher OAV. 

Figure 4.1 illustrates the progressive identification of the nearly 850 volatile constituents discovered in roasted coffee flavor. It shows that at the advent of chromatography (1956) 60 compounds were already known thanks to the remarkable contribution of Reichstein and Staudinger (1926) (see Table 4.4). 

Fig. 5.1 Progressive identification of hydrocarbons in roasted coffee volatiles...

Identified by Heins et al. (1966) in the headspace of coffee beans by one of the first capillary-GC/MS coupling, in spite of the fact that the experimental conditions and the resolution were still of relatively poor quality. The number of certified identifications was consequently strongly reduced. Merritt et al. (1970) found it in headspace of green and of roasted coffee. Wang et al. (1983) mentioned it as a new identification in a headspace analysis of roasted coffee it was also identified by Liardon and Ott (1984). 

The y-quinide G.15, the lactone of the main quinic acid (E.52) formed during roasting was identified in roasted coffee (chlorogenic lactones have been found in green coffee, see Section 2.1.4). The identification of isomers of this lactone was described by Maier s group (Scholz and Maier, 1990 Scholz-Bottcher et al., 1991 Scholz-Bottcher and Maier, 1992). The formation of the main lactone reached a maximum with a medium roast, whereas the minor isomers increased regularly. 

Identified in roasted coffee flavor by Merritt et al. (1963) as butylfuran (same remark as for 2-propylfuran, 1.6). The identification was also confirmed in the same way by Vitzthum and Werkhoff (1976b). It was identified in green coffee volatiles by Gutmann et al. (1979). Bakes and Bochmann (1987a) found it in coffee but not in model reactions when heating serine and threonine with sucrose. 

Identified by Stoffelsma et at. (1968) in roasted coffee flavor. In fact, the authors did not specify the furanic structure but, as they referred to Stoll et al. (1967) for the m-isomer, there is little doubt about the identification. Friedel et al. (1971) confirmed the identification for the /ram-isomer in an aroma complex of coffee (method in Gianturco et al., 1963). Cantergiani et al. (2001) found it in a green Mexican arabica (1.56% of the volatiles by GC on a polar column). 

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