Measurement of changes in fatty acid composition is useful for identification of
lipid class and fatty acids that are involved in oxidation reactions (7). However,
because the distribution of unsaturated fatty acids varies in different food systems,
for instance, the highly unsaturated fatty acids being located predominantly in
phospholipids of muscle foods, separation of lipids into neutral, glycolipid, phospholipid,
and other classes may be necessary (7, 15). Moreover, it is an insensitive
way of assessing oxidative deterioration. For comparison through calculation, oxidation
of 0.4% polyunsaturated fatty acids to monohydroperoxides would represent
a change of 16 meq oxygen/kg oil in peroxide value, whereas a change of less than
1.0 meq oxygen/kg oil could readily be detected by measuring peroxide value (12).
Additionally, the application of this method is limited because of its inability
to serve as an indicator of oxidation of more saturated lipids (7). Nevertheless,
its usefulness for measuring oxidation of highly unsaturated oils cannot be
underestimated.