Chemical composition of the volatile extracts from Brassica oleracea L. var. botrytis ‘Romanesco’ cauliflower seeds

The volatile and semi-volatile constituents of seeds from Brassica oleracea L. var. botrytis (L.), Romanesco group, Natalino, Campidoglio and Navona varieties, were extracted by simultaneous distillation-extraction using a Likens-Nickerson type apparatus. The volatile oil composition of three different Romanesco cauliflower seeds was analysed by GC and GC-MS. Forty-three compounds, representing more than 99.7% of the oil for the Natalino variety, 41 (99.6%) for the Campidoglio variety and 32 (99.5%) for the Navona variety were identified. The major compounds were cyanides such as 4-(methylthio)butyl cyanide (61.3, 66.3 and 79.6%, respectively), 3-(methylthio)propyl cyanide (21.7, 21.6 and 10.7%), and isothiocyanates such as 4-(methylthio)butyl isothiocyanate (5.3, 4.0 and 6.7%) for the three oils. The majority of identified volatile compounds were obtained by hydrolysis of glucosinolates. This study enabled us to infer the presence of 12 glucosynolate in Romanesco seeds.