Octadien-3-hydroperoxide

Figure 7. Reaction routes proposed for the formation of 1-octen-3-hydroperoxide (R= CH2 (CH2)4 ) and cis-1,5-octadien-3-hydroperoxide fCHs-- CH2- CH= CH CH2) (13).

Volatile decomposition products from autoxidized methyl linolenate were characterized for their intense aroma impact by capillary gas chromatography-olfactometry. The most intense volatiles included raf2.s,c/5-2,6-nonadienal, l-c/5-5-octadien-3-one, trans,cis-3,S-octadicn-l-onQ and c/5-3-hexenal (Table 4.4). The mechanism suggested for the formation of l-c/5-5-octadien-3-one assumes as precursor the 10-hydroperoxide formed by singlet oxidation that... 

The hydroperoxy epidioxides formed from photosensitized oxidized methyl linoleate are important precursors of volatile compounds, which are similar to those formed from the corresponding monohydroperoxides. Thus, 13-hydroperoxy-10,12-epidioxy-tra 5 -8-enoic acid produces hexanal and methyl lO-oxo-8-decenoate as major volatiles (Figure 4.24). The 9-hydroperoxy-10,12-epidioxy-rrans-13-enoic acid produces 2-heptenal and methyl 9-oxononanoate. Other minor volatile products include two volatiles common to those formed from the monohydroperoxides, pentane and methyl octanoate, and two that are unique, 2-heptanone and 3-octene-2-one. The hydroperoxy epidioxides formed from autoxidized methyl linolenate produce the volatiles expected from the cleavage reactions of linolenate hydroperoxides, and significant amounts of the unique compound 3,5-octadiene-2-one. This vinyl ketone has a low threshold value or minimum detectable level, and may contribute to the flavor impact of fats containing oxidized linolenate (Chapter 5). 

---