Cruciferous vegetables, related

Cruciferous vegetables have recently been identified as possessing anticarcinogenic properties (6). For example, indole-3-carbinol derived from indolylmethyl glucosinolate which is widely present in cruciferous vegetables has been shown to induce estradiol 2-hydroxylation in mice, and thereby reduce the risk of estradiol-linked mammary cancer (7,8). Moreover, 4-methylsulfinyl isothiocyanate (Sulforaphane) isolated from broccoli has been shown to induce several anticarcinogenic protective enzymes (9). However, development of excessive methanethiol-related off-flavors in cruciferous foods (e.g., sauerkraut) detracts from consumer acceptance of these cancer-preventive foods. 

Figure 2. Formation of methanethiol-related volatile sulfur compounds from S-methyl-L-cysteine sulfoxide via the action of cysteine sulfoxide lyase (C-S lyase) in cruciferous vegetables.

Methanethiol-related volatile sulfur compounds are derived from methyl methanethiosulfinate via nonenzymic chemical reactions. Methanethiol and dimethyl trisulfide are readily formed in a model system composed of methyl methanethiosulfinate and hydrogen sulfide (Figure 3 21,22) which is also a volatile component in disrupted tissues of cruciferous vegetables (4,5,17). Additionally, dimethyl disulfide has also been shown to be formed facilely from methyl... 

Methanethiol has a very low flavor threshold value (0.02 ppb in water 15), and possesses a strong, offensive, fecal-like odor (18). It also is readily converted to very unpleasant oxidized sulfurous off-flavor compounds with low detection thresholds, such as dimethyl disulfide and dimethyl trisulfide (18,25). Thus, suppression or modulation of methanethiol formation in cruciferous vegetables would le to a reduction of off-flavors associated with methanethiol-related compounds, and enhance the utility of controlled and modified atmosphere storage technologies for these vegetables. 

Unpleasant sulfurous odors associated with methanethiol-related volatile sulfur compounds limit consumer acceptance and the use of modified atmosphere technologies to extend the shelf life of cruciferous vegetables. Studies have revealed that both enzymic and nonenzymic systems which are present in caraway seed extracts... 

Haristoy X, Fahey JW, Scholtus 1 et al (2005) Evaluation of the antibacterial effects of several isothiocyanates ot Helicobacter pylori. Planta Med 71 326-330 Higdon IV, Delage B, WiUiams DE et al (2007) Cruciferous vegetables and human cancer risk epidemiologic evidence and mechanistic basis. Pharmacol Res 55 224-236 Holst B, WiUiamson G (2004) A critical review of the bioavailabihty of glucosinolates and related compounds. Nat Prod Rep 21 425-447... 

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