1 -propenyl 1 - propyl disulfide

Celery Apium graveolens 1-propenyl propyl disulfide (155) (3S,3aR)-Sedanolide (156), (3S)-sedanenolide (157) 131,175... 

Synonyms/Trade Names 4,5-Dithia-1-octene, Onion oil, 2-Propenyl propyl disulfide, Propyl allyl disulfide... 

Propenyl propyl disulfide. See Allyl propyl disulfide... 

Propenyl propyl disulfide 5905-52-2 Ferrous lactate Puramex FE 5910-87-2... 

Allyl propyl disulfide Propenyl propyl disulfide C6H13CI... 

Aliphatic sulfur compounds, in particular disulfides such as methyl propyl disulfide, dipropyl disulfide, and especially cis- and /ran -propenyl propenyl disulfide are mainly responsible for the typical odor of onion oil [235]. The presence of 2-hexyl-5-methyl-3(2H)-furanone [33922-66-6] is a characteristic of authenticity [235a]. 

SYNONYMS 4,5-dithia-l-octene, onion oil, 2-propenyl propyl di-sulfide, propyl allyl disulfide... 

This scarcity in thiosulfinates results in the low production of sulfides. Sulfides majorly detected in onion are dipropyl disulfide, dipropyl trisulfide, methyl propyl disulfide, methyl 1-propenyl disulfide, 1-prope-nyl propyl disulfide, and methyl propyl trisulfide (Boelens et al. 1971 Kallio and Salorinne 1990). Interestingly, more amount of sulfides with propyl group is produced in spite of the lower amount of S-propyl-L-cysteine sulfoxide than that of S-methyl-L-cysteine sulfoxide (Randle etal. 1995). 

Onion Oil. The distillation of onion pulp that has been allowed to stand for 12 h results in a dark brown oil, the composition of which has been studied by Brodnitz and Pollack [68]. Later work by Galetto and Bednarczyk [69] established that three components (starred in following listing) are of significance in determining the sensory profile. The principle components were identified as methyl-l-propyl disulfide, di-l-propyl trisulfide, 3,4-dimethyl thiophene, cis-l-propyl-propenyl disulfide, cis-methyl-l-propenyl disulfide, methyl-l-propyl tiisulfide, trans-methyl-l-pro-penyl disulfide, and di-l-propyl trisulfide. No allyl compounds were found to be present. 

The volatile oil contains allicin (diallyldi-sulfide-5-oxide diallyl thiosulfinate), allyl-propyl disulfide, diallyl disulfide, and diallyl trisulfide as the major components, with lesser amounts of dimethyl sulfide, dimethyl disulfide dimethyl trisulfide, allylmethyl sulfide, 2,3,4-trithiapentane, bis-2-propenyl... 

The flavor chemistry of sulfur compounds in onion is quite complex (19,20). Early reports of polysulfides and thiosulfinates were later demonstrated to be thermal artifacts from gas chromatographic analysis (20). Character impact sulfur compounds have been proposed for fresh, boiled, and fried onion. In raw, fresh onion, propyl propanethiosulfinate, propenyl propanethiosulfinate thiopro-panal S-oxide, and propyl methanethiosulfinate are impact contributors (18,19). A number of compounds contribute to the aroma character of cooked onion, of which dipropyl disulfide and allyl propyl disulfide provide key impact (18). Fried onion aroma is formed by heating the latter compound, and is characterized by... 

Nishimura and coworkers57-59 studied the y-radiolysis of aqueous solutions of sulfoxide amino acids. Sulfoxide amino acids are the precursors of the flavors of onions (S-propyl-L-cysteine sulfoxide, S-methyl-L-cysteine sulfoxide and S-(l-propenyl)-L-cysteine sulfoxide) and garlic (S-allyl-L-cysteine sulfoxide). In studies on sprout inhibition of onion by /-irradiation it was found that the characteristic flavor of onions became milder. In the y-radiolysis of an aqueous solution of S-propyl-L-cysteine sulfoxide (PCSO)57,58 they identified as the main products alanine, cysteic acid, dipropyl disulfide and dipropyl sulfide. In the radiolysis of S-allyl-L-cysteine sulfoxide (ACSO) they found that the main products are S-allyl-L-cysteine, cysteic acid, cystine, allyl alcohol, propyl allyl sulfide and diallyl sulfide. The mechanisms of formation of the products were partly elucidated by the study of the radiolysis in the presence of N20 and Br- as eaq - and OH radicals scavengers, respectively. 

In contrast with irradiation of ACSO and PCSO, where volatile products were formed (sulfides, disulfides and alcohols), no volatile products were formed in the radiolysis of aqueous solutions of S-(cis- l-propenyl)-L-cysteine. Here the authors found that reactions of OH" radicals are responsible for the formation of propyl-1-propenyl sulfides (cis and trans). 

The most important flavour compound in raw onions is thiopropanal-S-ox-ide, the lachrymatory factor [145,146]. Other important flavour compounds are 3,4-dimethyl-2,5-dioxo-2,5-dihydrothiophene and alkyl alkane thiosulfonates such as propyl methanethiosulfonate and propyl propanethiosulfonate with a distinct odour of freshly cut onions [35, 36, 147]. Various thiosulfinates that have a sharp and pungent odour may also contribute to the flavour of onions. These compounds, however, are rapidly decomposed to a mixture of alkyl and alkenyl monosulfides, disulfides and trisulfides (Scheme 7.3) of which dipropyl disulfide, methyl ( )-propenyl disulfide, propyl ( )-propenyl disulfide, dipropyl trisulfide and methyl propyl trisulfide are the most important contributors to the aroma of raw and cooked onions (Table 7.5, Fig. 7.6) [148-150]. Recently, 3-mercapto-2-methylpentan-l-ol was identified in raw and cooked onions eliciting intense meat broth, sweaty, onion and leek-like odours [142, 151]. 

Propyl propenyl disulfide (l-(Propyldithio)propene) n-C3H7SSCH=CHCH3... 

Onions Allium cepa) were shown to contain similar compounds, S-methyl and S-propyl-L-cysteine sulfoxide (20). The principal flavor precursor in onion is fmn -S( + )-l-propenyl-L-cysteine sulfoxide 21, 22, 23). It is responsible for the lachrymatory properties and bitter taste of freshly cut onion (22). All these compounds were cleaved by an S-alkyl-L-cysteine sulfoxide lyase from onion 24, 25) which yielded pyruvate and ammonia in addition to a sulfur compound. The enzyme has also been demonstrated in Bacillus subtilis 26) and in a number of the Cruciferae where the only substrate known is S-methyl-L-cysteine sulfoxide (27). The product presumably gives rise to dimethyl disulfide which is the odor of cooked cabbage. 

All possible combinations of methyl, propyl, allyl, and 1-propenyl disulfides (primarily), monosulfides, and trisulfides have been found among the volatile flavor components of onion (28,29, 30,31), garlic (32), caucas Allium victorialis) (33), and other Allium species 28) although proportions vary with species. These compounds are presumably derived from the corresponding thiolsulfinates. This is accomplished either by direct decomposition by an unknown mechanism with evolution of SO2 (32) or by interaction with cysteine to produce a mixed disulfide (15),... 

PENTYL-PROPYL-SULFIDE 1-OCTANETHIOL BUTY-DISULFIDE ALPHA-METHYLSTYRENE PROPENYL-BENZENE, CIS PROPENYL-BENZENE, TRANS M-METHYL-STYRENE 0-METHYL-STYRENE P-METHYL-STYRENE PROPYLBENZENE CUMENE... 

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