Volatile constituents of blue‐coloured hybrid tea rose flowers

ABSTRACTThe volatile constituents of ‘Blue Moon’ and ‘Blue Perfume’ rose flowers, which, on an olfactory basis, are classified as a ‘blue type’ were analysed using Aromascope® technology (modified headspace technology) and solvent extraction methods followed by gas chromatography–mass spectrometry analysis. One hundred and eighty components were identified in the headspace volatile components of ‘Blue Moon’ flower and 188 components were identified in solvent extracts. Among them, geraniol, nerol, citronellol, 1,3‐dimethoxy‐5‐methylbenzene and dihydro‐β‐ionol were identified as the main odour components. On the other hand, in ‘Blue Perfume’, 165 components were identified in the headspace volatile components and 150 components were identified in solvent extracts. Among them, geraniol, nerol, citronellol, neral, and geranial were identified as the major odour compounds. From both rose flowers, three components were newly identified: 2‐isopropyl‐4‐methylthiazole, (Z)‐cyclododec‐9‐enolide (yuzu lactone), and methyl cis‐(Z)‐jasmonate. 2‐Isopropyl‐4‐methylthiazole and methyl cis‐(Z)‐jasmonate were identified in both of the headspace components and solvent extracts of the two types of rose flower, and then yuzu lactone was identified only in solvent extracts as the one of the minor components. Several components identified in both flowers have asymmetric carbon atoms in their molecules, leading us to analyse their chirality. For the first time, the enantiomer ratios of linalool, (E)‐nerolidol, theaspiranes and dihydro‐β‐ionol could be assigned by multi‐dimensional gas chromatography–mass spectrometry. The results were as follows in both rose flowers. The ratio of the (S)‐enantiomer vs. the (R)‐enantiomer of linalool was 8:92. Only the (S)‐enantiomer was detected for (E)‐nerolidol and dihydro‐β‐ionol. The ratios of the (2R,5R)‐enantiomer vs. the (2S,5S)‐enantiomer in theaspirane A and the (2R,5S)‐enantiomer vs. the (2S,5R)‐enantiomer in theaspirane B were about 4:96. Copyright © 2013 John Wiley & Sons, Ltd.