Furaneol

Wild and cultivated blackberries have been used as food and medicine for hundreds of years [106]. Approximately 150 volatiles have been reported from blackberries [107]. The aroma profile is complex, as no single volatile is described as characteristic for blackberry [108, 109]. Several compounds have been suggested as prominent volatiles in blackberries using AEDA, e.g. ethyl hexanoate, ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, 2-heptanone, 2-undecanone, 2-heptanol, 2-methylbutanal, 3-methylbutanal, hexanal, ( )-2-hexenal, furaneol, thiophene, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 2-methylthiophene, methional, a-pinene, limonene, linalool, sabinene. 

The majority of the more than 100 odorants (reviewed in [1]) synthesised for use as internal standards are labelled with deuterium. However, during the quantification procedure some deuterated odorants might undergo deuterium-protium exchange, which would falsify the results. Examples are 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) [68, 69] and 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon) [70], which are consequently labelled with... 

Fig. 17.6 Stereodifferentiation of Furaneol (J) and mesifuran (2) from strawberries a HPLC chromatogram of strawberry extract mesifuran (fraction ft), Furaneol (fraction/2) b HPLC fractions, analysed by enantioselective capillary GC [23]...

Flavorzyme is a commercially available proteolytic enzyme preparation by Novo Nordisk Bioindustrials. It can be used to obtain a meat-like process flavouring from defatted soybean meal. With the help of aroma extract dilution analysis, Wu and Cadwallader [61] showed in their study of 2002 the presence of key aroma compounds of roasty, meat-like aroma in the enzymatically hydrolysed and heated hydrolysed protein, e.g. maltol, furaneol, methanethiol and furanthiol derivatives. 

In spite of the intensive effort regarding the biosynthesis of Furaneol (including the detection of some important enzymes), the biosynthesis in plants is still not fully understood [87]. 

Besides the aforementioned lactones, Furaneol , 2,5-dimethyl-4-hydroxy-2H-... 

Amongst furans are several compounds of great importance in fragrances and flavours. The rose owes some of its odour to a terpenoid furan, rosefuran, coffee some of its characteristics to furylmethanethiol and related compounds. Compounds like the 3-furanone derivative furaneol (10) are particularly interesting for their odours depend upon concentration— furaneol can seem to resemble pineapple, caramel, burnt toast etc. Furaneol is a dihydrofuran-3-one dihydrofuran-2-ones are obviously lactones and are usually dealt with as such. 

Furanones have been prepared by treatment of y-ketoacids with acetic anhydride. Furanones have also been formed by hydrolysis and dehydrobromination of j8,y-dibromoacids (B-50MI31200). The furan-3(2//)-one system (164) has been prepared by intramolecular cyclization of the diazoketones (163) (74TL3073). Some natural 3(2//)-furanones are known furaneol (166), occurring in strawberries and pineapples, is obtained by acid or base treatment of the dihydroxydiketone (165) (73JOC123). 

Only a few natural 3(2H)-furanones have been found. Furaneol (166) is present in strawberries and pineapples (73JOC123). 

Hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) 5,6-[13C2] Blank et al., 1997... 

From the wine aromas of Pollux, Castor, and Riesling grapes, Rapp et al. and Schreier and Paroschy have isolated an undesirable strawberry aroma by GC-MS (80V13, 81MI112). This lactone was characterized as 2,5-dimethyl-4-hydroxy-2,3-dihydro-3-furanone 8 ("furaneol") having an odor threshold of 50-100 ppb. 

Sarrazin et al. (2007a) established that the development of B. cinerea led to an increased concentration of homofuraneol, furaneol, norfuraneol, and phenylacetaldehyde in wines produced from botrytized grapes, in comparison with wines made from healthy grapes. 

FIGURE 7.10 Structures of volatile compounds characterized from toasty caramel aroma released in wine from toasted woods during aging. (1) 3,5-dihydroxy-2-methyl-4H-pyran-4-one (2) 3-hydroxy-2-methyl-4H-pyran-4-one (3) 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) (4) 4-hydroxy-2,5-dimethylfuran-3(2H)-one (furaneol) (5) 2,3-dihydro-5-hydroxy-6-methyl-4H-pyran-4-one (dihydromaltol) (6) 2-hydroxy-3-methyl-2-cyclopenten-l-one (or cyclotene) (Cutzach et al., 1997 ) (7) 3-hydroxy-4,5-dymethyl-2(5H)-furanone (Sotolon Camara et al., 2006a,b,c) (8) 2-furanmethanethiol (furfurylthiol Tominaga et al., 2000). 

An Isolation and concentration scheme should be appropriate for the sample under Investigation. As an example of this, a distillation technique would not be satisfactory for separating caramel aroma compounds such as Maltol, Cyclotene, or Furaneol which possess an enolone structure and do not steam distil. 

Furaneol) and 4—hydroxy—5—methyl—3(2H) furanone (HMF) which were identified as major furanone components in meat (14.15). When these compounds are heated in... 

The experiments have been completed by additional reaction of xylose, fructose and some characteristic sugar degradation products like cyclotene, Furaneol and diacetyl and by thermal decomposition of Ama-dori rearrangement products. It is well knwon that sugars can react with suitable amino compounds very easily. In the course of these reactions sugars are mostly decomposed and brown melanoidins are formed. By-products of these melanoidins are many volatile compounds of characteristic aroma properties. They are also responsible for the well known aromas of heated food like meat, coffee and bread. 

It is suggested that it forms Furaneol by dehydration and and hydrogenation of the exocyclic methylene group. 

Cyclotene is the precursor of dihydrocyclopentapyrazines after having reacted with ammonia respectively amino acids to form cyclotene imine. Figure 2 demonstrates not only the isomerization and transformation of this compound but also the formula of bis-dihydro-cyclopentapyrazines as special reaction products. They are formed by condensation of cyclotene-imine and represent a mixture of 4 di-astereomeric compounds. These compounds produce identical mass spectra (Shibamoto et a 1,16). We have carried out corresponding experiments by heating Furaneol with phenylalanine or serine in an autoclave at 180 0 C. As Figure 3 demonstrates some monocyclic pyrazines are formed by reaction of the degradation products from Furaneol. 

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