Passion fruit sulfur compounds

B. Weber, B. Maas and A. Mosandl, Stereoisomeric flavor compounds. 72. Stereoisomeric distribution of some cliiral sulfur containing trace components of yellow passion fruits , ]. Agric. Food Chem. 43 2438-2441 (1995). 

M. Winter, A. Furrer, B. Willhalm and W. Thommen. Identification and Synthesis of two New Organic Sulfur Compounds from the Yellow Passion Fruit (Passiflora edulis f. flavicarpa). Helv. Chim. Acta, 52, 1613-1620 (1976). 

B. Weber, A. Dietrich, B. Maas, A. Marx, 1. Oik, and A. Mosandl. Stereoisomeric Flavour Compounds LXVI Enantiomeric distribution of the chiral sulfur-containing alcohols in yellow and purple passion fruits. Z. Lebensm. Unters. Eorsch., 199. 48-50 (1994). 

The enantiomeric composition of the sulfur containing compounds in yellow and purple passion fruit is still unknown. The results of quantitative and qualitative investigation of sulfur containing components showed the best correlation to the organoleptic properties of pas-sionfruit concentrates. 

Sulfur compounds in the thiol family (or mercap-tans) are generally held responsible for olfactory defects (Section 8.2.2). However, their major contribution to the aromas of certain fruits and aromatic plants has been clearly estabhshed. Thus, specific thiols are involved in the characteristic aromas of fruits such as blackcurrant (Rigaud et al., 1986), grapefruit (Demole et al., 1982), passion fruit (Engel and Tressel, 1991) and guava (Idstein and Schreier, 1985 Bassols and Demole, 1994). Two mercaptans, ethyl-3-mercaptopropion-ate and ethyl-2-mercaptopropionate, have been identifled as components in the aroma of Vitis labrusca grapes (variety Concord) (Kolor, 1983 Winter et al, 1990). 

C,H,60S, Mr 160.27 discovered and synthesized in 1976 as the typical flavor compound of the yellow passion fruit (Passiflora edulis) (see fruit flavors). Racemic cis-Zira/is-mixture 1 10, oil with an exotic fruity odor, bp. 85 -86 °C (1.6 kPa). Synthesis and sensory evaluation of the four stereoisomers demonstrated that the (-F)-(2S,4/f)-form was the compound with the typical passion fruit character, olfactory threshold in water 2 jmb, [alo" -f56.1 (CCI4). According to chiral analysis, however, the passion fruit contains the (4S)-epimer pair with an untypical, sulfurous, herby-green or, respectively flowery odor (-)-(2R,4S), [a]g -56.1 , and (-)-(2S,4S), (a]g -117.6°. For biosynthesis, see Ut.. ... 

Additionally, aroma components of some foods are six-membered heterocycles containing an oxygen atom and sulfur in the molecule. An example of such a compound is (2J ,4S)-2-methyl-4-propyl-l,3-oxathiane (8-168), also known as ds-tropathiane, which occurs in the yellow passion fruit Passiflora edulis, f. flavicarpa, Passifloraceae), pineapple Ananas comosus, Bromeliaceae), whisky and white wines. 

Significant aliphatic sulfur compounds are methional, 3-methyl-but-2-ene-1-thiol, 3-mercapto-3-methylbutan-l-ol (8-124), its ester 3-mercapto-3-methylbutyl formate, methanethiol and dimethyltrisulfide. 3-Mercapto-3-methyl-l-ol also occurs in passion fruit and blackcurrant, and as a putative cat pheromone in cat urine, where it is formed as a degradation product of amino acid L-felinine (see Section 2.2.1.2.2). Of more than 70 known pyrazines, the most important compounds in roasted coffee are isopropylpyrazine, 2-isobutyl-3-methoxypyrazine, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 2,6-dimethyl-3-vinylpyrazine and 2-ethyl-6-methyl-3-vinylpyrazine. Pyridine and its alkyl derivatives and bicyclic pyridines have a negative impact on the quality of coffee aroma. Important aromatic... 

The tropical category is one of the most important areas for new discoveries of key impact flavor compounds. Analyses of passion fruit and durian flavors have produced identifications of many potent sulfur aroma compounds (18). Among these is fropathiane, 2-methyl-4-propyl-l,3-oxathiane, which has an odor threshold of 3 ppb (15). For pineapple, 2-propenyl hexanoate (allyl caproate) exhibits a typical pineapple character (11) however, Furaneol, ethyl 3-methyl-thiopropionate, and ethyl-2-methylbutyrate are important supporting character impact compounds (31). The latter ester contributes the background apple note to pineapple flavor. Another character impact compound, allyl 3-cyclohexyl-... 

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