Sulfur compounds onion

Plants of the genus Allium, e.g. garlic Allium sativum), leek Allium amp-eloprasum), and onion Allium cepa), produce a bewildering variety of sulfur compounds. Selenium analogs for some of these have also been found (Section 11.1.3.6). Much work has focused on garlic (contains more than 100 such materials) and onion.56,66,67 Key compounds for formation of the Allium sulfur-containing secondary metabolites are sulfoxides of cysteine derivatives,... 

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]. 

Another German investigator (Semmler, 1892) also produced garlic oil via steam distillation. The oil yielded diallvl disulfide, CH2=CHCH2SSCH2 CH = CH2, with minor amounts of diallyl trisulfide and diallyl tetrasulfide present. The oil yielded by similar experimentation with onions was different, containing essentially propionaldehyde, C2H5CHO, plus a number of sulfur compounds, of which dipropyl disulfide, C5H12S2, was one. 

Block, E. The Chemistry (Sulfur Compounds) of Garlic and Onions, Sci. 

Sulfur compounds are used to make rubber strong enough to be used in tires, in a process called vulcanization. Sulfur is also used to make detergent, paper, fertilizers, and medicines. Several sulfur compounds have a strong odor to them. Onions, garlic, skunk spray, and even bad breath get their unique odor from sulfur compounds. Sulfur by itself has no smell. 

Sulfur compounds Onion and garlic Anti-atherosclerotic and anti-thrombotic Wang and Ng (1999)... 

Garlic, Allium sativum L., is a species in the onion family, Alliaceae. Onion, shallot, and leek are close relatives. Garlic has been used throughout history for both culinary and medicinal purposes. It has a pungent hot sensation that mellows and sweetens considerably with cooking. A large number of sulfur compounds contribute to the smell and taste of members of the onion family. Diallyl disulfide and diallyl sulfide are... 

Members of the allium family (onions, garlic, and leeks) contain cysteine sulfoxide derivatives (allyl sulfur compounds), such as allicin and alliin (see Figure 14.9). When the plant cells are damaged, the enzyme alliinase is released from vacuoles and catalyzes the formation of thiosulfinates and thiols, including the lachrymator thiopropanal S-oxide. Their function in the plant is presumably to provide protection against attack by pests. 

A large number of organic sulfur compounds have been detected in extracts or distillates prepared from garlic, onions, or other Allium species. This chemistry has been reviewed by Block. Polysulfanes have been detected in many of these preparations but most recent results show that fresh extracts of garlic, prepared under mild conditions (20 °C), did not show any polysulfanes R-S -R n > 2) when analyzed by RP-HPLC analysis. ... 

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. 

Alliums are garlic, onions, scallions, shallots, ramps, leeks, and chives, which are all botanically related. Although they are usually thought of as foods, these powerful herbs contain many active sulfur compounds that have shown the ability to prevent cancer. 

Thiols and many other sulfur compounds have nauseating aromas. They are found in substances as different as the defensive spray of the North American striped skunk, onions, and garlic. 

Trithiane itself has been found among the volatile sulfurous compounds of Shiitake mushrooms extracted from the homogenate of fresh mushrooms <1986JFA830> and 2,4,6-triethyl-l,3,5-trithiane was identified among the flavor compounds in the steam distillate of onions <1992MI459> analyzed by GC and characterized by GC-MS. Other than that, 1,3,5-trioxane derivatives are not found that often in natural products as their sulfur analogs. Only... 

Naturally occurring sulfur-containing compounds are found especially in the cruciferous vegetables, such as broccoli, brussels sprouts, cabbage, kale, and tnmips (Brassica spp.), and the onion Allium spp.) and mustard (Sinapis spp.) families. The sulfur compounds in these groups are slightly different and, consequently, each has specific health benefits. 

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