Formation of methanethiol and dimethyl disulfide in crushed tissues of broccoli florets and their inhibition by freeze-thawing.
The formation of methanethiol and dimethyl disulfide in crushed, homogenized, and frozen-thawed tissues of broccoli florets was investigated. These volatile sulfur compounds were produced in crushed florets, but their formation was inhibited in frozen-thawed tissues. Only dimethyl disulfide was formed in homogenized tissues. High pH treatment triggered the release of dimethyl disulfide in frozen-thawed tissues and also enhanced the action of cysteine sulfoxide lyase in all disrupted tissues. Methyl methanethiosulfinate and methyl methanethiosulfonate were not detected in crushed florets; thus, the favored mechanism for the formation of methanethiol and dimethyl disulfide is the chemical disproportionation of methanesulfenic acid. In contrast, the formation of dimethyl disulfide in frozen-thawed and homogenized tissues occurs from the chemical disproportionation of methyl methanethiosulfinate that was detected in these tissues. The inhibition of dimethyl disulfide production during freeze-thawing must be caused by a sudden drop in the pH of the tissue, adherence of dimethyl disulfide on the tissue surfaces, and weakening of the cysteine sulfoxide lyase activity under acidic conditions.
Tulio
Artemio Z
AZ
Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan.
Yamanaka
Hiroyuki
H
Ueda
Yoshinori
Y
Imahori
Yoshihiro
Y
D001937:Brassica / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000032:analysis*; D005511:Food Handling; D005615:Freezing; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D013438:Sulfhydryl Compounds / Q000032:analysis*; D013649:Taste; D014835:Volatilization
D013438:Sulfhydryl Compounds; C005231:methylmercaptan; D004121:Dimethyl Sulfoxide