2-Ethyl-3,6-dimethylpyrazine

A -Pyrroline (12i) is emitted by sexually mature male Mediterranean fruit flies (Ceratitis capitate), together with 2-ethyl-3,5-dimethylpyrazine (21b) (Tables II and III). This cyclic imine (12i) is the key component in the sexual attraction of virgin female flies to males (102). Xanthommatin (58) and two pteridines (81 and 84) are also found in this fruit fly (Tables V and VI). 

Ethyl-3,5-dimethylpyrazine Roasted beef AIanine/2-Oxopropanal [106]... 

Polyurethanes (PU) The odor of many polyurethanes is caused by fishy smelling low molecular weight amines, mostly methylamines like trimethylamine, degradation products of the amine catalysts used during production. In some cases after evaporation of the fishy smelling amines, other odor qualities remain. One noticeable odor of PU samples was earthy, nutty, which can often be attributed to substituted pyrazines, formed by condensation of two a-aminoketones, subsequent oxidation or alkylation by aldehydes. One example is 2-ethyl-3,5-dimethylpyrazine (Mayer and Breuer, 2006). 

Coffee (Arabica) /3-Damascenone, 2-furylmethanethiol, 3-sulfanyl-3-methylbutyl formate (126), homofuronol (127), furaneol, guaiacol, 4-vinylguaiacol, methional, sotolone, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, vanillin, 4-ethylguaiacol, homosotolone (128) 147... 

Ethyl-3,6-dimethyl-5-propionylpyrazine 2-Ethyl-3,5-dimethylpyrazine 2-Ethyl-3,6-dimethylpyrazine... 

Aroma models were prepared for gruyere by applying the methods reported for emmental [57, 58], The aroma of the models was similar to that of the original cheeses. Consequently, it was concluded that 2-/3-methylbutanal, methional, dimeth-yltrisulphide, phenylacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, methanethiol, as well as acetic, propionic, butyric, 3-methylbutyric and phenylacetic acids are the key odorants of gruyere. 

Acetyl-1-pyrroline 4-Mercapto-4-methyl-2-pentanone 2-Ethyl-3,5-dimethylpyrazine (Popcorn-like) (Meaty) (Nutty)... 

Pyrazine, 2-ethyl-3,5-dimethyl-, 2-ethyl-3,5-dimethylpyrazine, 2,6-dimethyl-3-ethylpyrazine 113925-07-0] FEMA 3150... 

Buttery R.G. and Ling L.C. (1997) 2-Ethyl-3,5-dimethylpyrazine and 2-ethyl-3,6-dimethylpyrazine odor thresholds in water solution. Lebensm. Wiss. Technol. 30, 109-10. 

The Maillard reaction between reducing sngars and amino acids under specific conditions (pH, water activity, and temperature) is primarily responsible for the production of heterocyclic volatile compounds such as pyrazines, pyridines, pyrroles, furans, and the Strecker aldehydes. Maillard reactions produce many potent aroma compounds identified in some roasted tree nuts, including 3-methylbutanal, 2,3-butanedione, methional, phenylacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, and 2,5-dimethyl-4-hydroxy-3(2//)-furanone, among others. 

Rye bread In comparison to white bread the crust only contains small amounts of 2-acetyl-1-pyrroline, but instead more 3-methylbutanal, methional, 2,3-butanedi-one, 2-ethyl-3,5-dimethylpyrazine (see pyrazines), Fu-raneol , phenylacetaldehyde and 4-vinylguaiacol. Ut. l. Agric. Food Chem 44,1515 (1996) Maarse, p. 41 -77 Ohloff. 

Sesame seed (roasted) flavor. According to aroma extract dilution analysis, 2-furylmethanethiol, guaiacol, 2-phenylethanethiol (CgHn is, Mr 138.23), and Furaneol have the highest dilution factors in the flavor of roasted sesame seeds, besides 4-vinyl-guaiacol, 2-pentylpyridine (C,oH,5N, Mr 149.24), 2-acetyl-l-pyrroline, 2-acetylpyrazine, and 2-ethyl-3,5-dimethylpyrazine (see pyrazines). 

Ethyl-3,5-dimethylpyrazine. See 2-Ethyl-3,5(6)-di methyl pyrazi ne 2-Ethyl-3,5(6)-dimethylpyrazine CAS 13925-07-0 55031-15-7 EINECS/ELINCS 237-694-1 FEMA 3149... 

Guan and collaborators studied the effect of 14 alkylpyrazines, known to be ant alarm pheromones, in combination with bait on fire ants (Figure 12) (14JAF11924).Testing at a dose range ofO.l—1000ng,it was found that out of the 14 alkylpyrazines, 4 compounds,2,3,5-trimethylpyrazine (88),2,3-diethyl-5-methylpyrazine (89), and a mixture of 2-ethyl-3,6-dimethylpyrazine (90) and 2-ethyl-3,5-dimethylpyrazine (91) promoted a significant increase in the alarm responses. Furthermore, it was determined that out of the mixture of 2-ethyl-3,6-dimethylpyrazine (90) and 2-ethyl-3,5-dimethylpyrazine (91), the former was substantially more active than the latter. 

Alkylpyrazines such as 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, and 2,3,5,6-tetramethylpyrazine were isolated from Bacillus species [307, 308]. The marine aectic bacterium from the Cytophaga-Flexibacter-Bacteriodes (CFB) phylum produces 2-ethyl-3,6-dimethylpyrazine and 2-ethyl-3,5-dimethylpyrazine [309]. The potential pathways for the formation of alkylpyrazines have been discussed by several authors. Murray et al. suggested a biosynthetic pathway for the formation of... 

Chang et al. [73] and Nawar et al. [74] have identified many of the volatiles formed during deep fat frying. They have found numerous acids, alcohols, aldehydes, hydrocarbons, ketones, lactones, esters, aromatics, and a few miscellaneous compounds (e.g., pentylfuran and 1,4-dioxane) as products of deep fat frying. More recently, Wagner and Grosch [75] have studied the key contributors to French fry aroma. The list of key aroma compounds in French fries includes 2-ethyl-3,5-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 3-isobutyl-2-methoxypyrazine, (E,Z), (E,E)-2,4-decadienal, trans-4,5-epoxy-(E)-2-decenal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, methylpropanal, 2- and 3-methylbutanal, and methanethiol. If one examines this list, it is obvious that the Maillard reaction (pyrazines, branched chain aldeydes, furanones, and methional), and lipid oxidation (nnsaturated aldehydes) are the primary sources of this characteristic aroma. 

Fig. 5.4. Headspace analysis of aroma substances of white-bread crust, a Capillary gas chromatogram (the arrows mark the positions of the odorants), b FD chromatogram. Odorants 1 methylpropanal, 2 diacetyl, 3 3-methylbutanal, 4 2,3-pentanedione, 5 butyric acid, 6 2-acetyl-1-pyrroline, 7 l-octen-3-one, 8 2-ethyl-3,5-dimethylpyrazine, 9 (E)-2-nonenal (according to Schieberle and Grosch, 1992)...

In the case of French fries (Fig. 5.8), 19 aroma substances appearing in the FD-factor range 2 -2 were identified (cf. legend of Fig. 5.8). Based on the high FD factors, the first approximation indicates that methional, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylp)razine and (E,E)-2,4-decadienal substantially contribute to the aroma of French fries. 

Fig. 5.8. FD chromatogram of the volatile fraction of French fries. Ordinate n, number of 1 + 1 dilutions. Abscissa retention index (RI) on the capillary SE-54. The following odorants were identified 1 methional, 2 2-acetyl-1-pyrroline, 3 dimethyltrisulfide, 4 l-octen-3-one, 5 phenylacetaldehyde, 6 2-ethyl-3,6-dimethyl-pyrazine, 7 2-ethyl-3,5-dimethylpyrazine, 8 nonanal, 9 (Z)-2-nonenal, 10 2,3-diethyl-5-methylpyrazine, 11 (E)-2-nonenal, 12 2-ethenyl-3-ethyl-5-methylpyrazine, 13 2-isobutyl-3-methoxypyrazine, 14 dimethyltetrasulfide, 15 (E,E)-2,4-nonadienal, 16 (Z)-2-decenal, 17 (E,Z)-2,4-decadienal, 75 (E,E)-2,4-decadienal, 79trans-4,5-epoxy-(E)-2-decenal (according to Wagner and Grosch, 1997)...

---