Furaneol caramel-like odor

Boiled beef and pork differ in their aromas. Beef smells more intensely meaty, sweet-caramel-like and malty, whereas pork is stronger in sulphurous and fatty odour notes [21, 37J. According to Table 6.29, the pronounced odour notes of beef are caused by high concentration of furaneol (no. 1), 2-furfurylthiol (no. 2), 3-mercapto-2-pen-tanone (no. 3) and 2-methyl-3-furanthiol (no. 6). Omission experiments confirmed that these volatiles and in addition octanal, nonanal, (E,E)-2,4-decadienal, are the key odorants of boiled beef [21 ]. The higher concentration of the caramel-like smelling furaneol (no. 1) in beef than in pork is due to higher levels of its precursors glucose-6-phosphate and fructose-6-phosphate [37],... 

Omission of furaneol (no. 1 in Table 6.41) led to a very significant aroma defect which was perceived by all six members of the panel. The model smelt green and fruity. When (Z)-3-hexenal (no. 2) was missing, the caramel-like/sweetish note of furaneol predominated ]75]. In contrast, a lack of odorants nos. 9-12 was only detected by one or two panellists, respectively, indicating a lower aroma impact of these substances. 

On the basis of high OAV, 2-acetyl-l-pyrroline (no. 1), 2-furfurylthiol (no. 2), 2-phenylethylthiol (no. 3) and furaneol (no. 4) are the most important contributors to the overall roasty, caramel-like aroma of the moderately roasted sesame. The two thiols nos. 2 and 3, but not the unstable 2-acetyl-l-pyrroline (no. 1), were also identified as key odorants of white and black sesame seeds which had been longer roasted and which elicited intense burnt or even rubbery odour notes ]97, 98]. 

The caramel character is associated with a planar, contiguous C-alkyl-enol carbonyl group (aUcyl-C=C(OH)-C 0) in the molecule [58]. Maltol (Figure 5.6a) was one of the first compounds in this class to be identified in foods. Ethyl maltol (2-ethyl-3-hydroxy-4(4H)-pyranone) also has a caramel odor but is approximately four to six times stronger in flavor strength than maltol. Furaneol (4-hydroxy-2,5-dimethyl-3(2H)furanone, Figure 5.6b) is the trade name of a compound used extensively in the flavor industry and, like maltol and ethyl maltol, is a flavor enhancer for sweet products. Furaneol itself has a burnt pineapple odor. 

Chocolate represents a highly complex flavor system for which no single character impact has been identified. Vanillin and Furaneol contribute to the sweet, caramel background character of milk chocolate (57). 5-Methyl-2-phenyl-2-hexenal provides a deep bitter, cocoa note, and is the aldol reaction product from phenylacetaldehyde and 3-methylbutanal, two Strecker aldehydes formed in chocolate (58). 2-Methoxy-5-methylpyrazine and isoamyl phenylacetate have chocolate, cocoa, nutty and cocoa-like notes, respectively, and both are used in synthetic chocolate flavors (59). Systematic studies of key odorants in milk chocolate were performed using aroma extract dilution analysis however, character impact compounds unique to chocolate flavor were not reported (57,60). 

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