Volatile constituents from Romanesco cauliflower

The volatile and semi-volatile constituents of Brassica oleracea L. var. Botrytis L., Romanesco group, Navona variety, were extracted by steam distillation from leaves and inflorescence, using a Likens–Nickerson-type apparatus. The extracts from fresh, ripening and frozen vegetables were investigated by gas chromatography and mass spectrometry. From the fresh leaves extract, a total of 61 compounds were identified, representing 96.8% of the oil. The major constituent was found to be hex-3(Z)-enol (61.1%). From fresh disrupted inflorescence tissues of Romanesco, 35 compounds were detected, representing 97.7% of the extract. Dimethyl disulfide, dimethyl trisulfide and hex-3(Z)-enol were identified as major constituents of the hydrodistillation products, representing, respectively, 30.2, 24.2 and 21.7% of the volatiles. From ripening and frozen inflorescence tissues, dimethyl disulfide and trisulfide were again detected as predominant components. In the latter, hex-3(Z)-enol had almost disappeared (0.8%) whereas dimethyl trisulfide represented 49.7% of the oil. This is the first report concerning the steam distillation compounds present in the leaves and inflorescence tissues of this species.