Identification of 1-cyano-2,3-epithiopropane in volatiles of a model system from Brussels sprouts (Brassica oleraceae L var bullata subvar gemmifera DC)

Volatiles produced in model systems consisting of a crude enzyme preparation from Brussels sprouts (Brassica oleraceae L var bullata subvar gemmifera DC), sinigrin, ascorbic acid and 2‐mercaptoethanol were investigated using gas chromatography‐mass spectroscopy. 2‐Propen‐1‐yl isothiocyanate was the only breakdown product of sinigrin in the absence of 2‐mercaptoethanol but in its presence 1‐cyano‐2,3‐epithiopropane and small amounts of 2‐propen‐1‐yl cyanide also were formed. The identification of the 1‐cyano‐2,3‐epithiopropane was confirmed by comparison with a standard produced by autolysis of Crambe abyssinica L seed and with published mass spectra. The presence of 1‐cyano‐2,3‐epithiopropane in volatile extracts of unblanched, frozen stored Brussels sprouts is also reported.