Dipropyl trisulfide

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]. 

Shallots Allium ascalonicum) are an allium wherein the bulb laterals separate into individual bulbs. Apparently, shallots do not develop a lachrymatory factor, such as thiopropanal-S-oxide upon maceration [35]. The major aroma constituents in shallots are similar to those found in A.cepa. In raw shallots, the most important aroma compounds appear to be dipropyl disulfide, propyl ( )-prope-nyl disulfide, methyl propyl trisulfide, dimethyl trisulfide and dipropyl trisulfide (Table 7.5, Fig. 7.6) [35, 152, 153]. 

Dipropyl trisulfide (No. 585) was evaluated by the Committee in 1999. It was concluded that dipropyl trisulfide was not a safety concern at current levels of intake. 

Diethyl-1,2,4-trithiolane (No. 1686) was evaluated by the Committee at the present meeting. It was concluded that 3,5-diethyl-1,2,4-trithiolane was not a safety concern at current levels of intake. 3,5-Diethyl-1,2,4-trithiolane is anticipated to undergo oxidation and subsequent elimination in the urine or reduction to the free dithiol (Nelson Cox, 2000). Dipropyl trisulfide (No. 585) was evaluated by the Committee in 1999. It was concluded that dipropyl trisulfide was not a safety concern at current levels of intake. 

Dipropyl-1-propanamine N,N-Dipropyl-1-propylamine. See Tri-n-propylamine Dipropylthiocarbamic acid, S-ethyl ester. See Ethyl dipropylthiocarbamate Dipropyl trisulfide CAS 6028-61-1 FEMA 3276... 

Dimethylpyrrole Dimethyl succinate Dimethyl sulfide 1,3-Diphenyl-2-propanone Dipropyl trisulfide... 

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 also contains a trace of volatile oil composed mainly of sulfur compounds, with dipropyl disulfide as the main component (but not an important flavor contributor). Others present include the three important flavor contributors methylpropyl disulfide, methylpropyl trisulfide, and dipropyl trisulfide, as well as aUylpropyl disulfide, dimethyl disulfide, 3,4-dimethylthiophene, methyl-cfr-pro-penyl disulfide, and others. 

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