2009_Book_FoodChemistry

194 3 Lipids
Fig. 3.20. Autoxidation of oleic acid. Primary reaction products: I 11-Hydroperoxyoctadec-9-enoic acid;
II 9-hydroperoxyoctadec-10-enoic acid, III 10-hydroperoxyoctadec-8-enoic acid, IV 8-hydroperoxyoctadec-9-
enoic acid
Fig. 3.21. Autoxidation of linoleic acid. Primary reaction products: I 13-Hydroperoxyoctadeca-9,11-dienoic acid,
II 9-hydroperoxyoctadeca-10,12-dienoic acid
Autoxidation of linolenic acid yields four
monohydroperoxides (Table 3.28). Formation
of the monohydroperoxides is easily achieved
by H-abstraction from the bis-allylic groups in
positions 11 and 14. The resultant two pentadiene
radicals then stabilize analogously to linoleic
acid oxidation (Fig. 3.21); each radical corresponds
to two monohydroperoxides. However,
the four isomers are not formed in equimolar
amounts; the 9- and 16-isomers predominate
(Table 3.28). The configuration of the conjugated
double bonds again depends on the reaction