Thiols, Thioethers, Di- and Trisulfides

An abundance of sulfurous compounds is obtained from cysteine, cystine, monosaccharides, thiamine and methionine by heating food. Some 

Methanethiol oxidizes easily to dimethyldisul-fide, which can disproportionate to dimethylsul-fide and dimethyltrisulfide (Formula 5.8). 

3-Mercapto-2-methylpentan- l-ol Meat-like, like onions 0.0016 

Due to its very low odor threshold (Table 5.21), the trisulfide is very aroma active and is frequently found in dilution analyses as a companion substance of methanethiol. For the moment, it is unknown whether it is derived from food or whether it is an artifact obtained in the isolation and concentration of volatile compounds. 

Except for the exceptionally reactive 2-mer-captoethanal, the sulfur compounds mentioned above have been identified in practically all protein-containing foods when they are heated or stored for a prolonged period of time. 

---