Nonenzymatic Lipid Oxidation by Lactoperoxidase. Effect of Heat Treatment

The enzyme laetoperoxidase might, like other hemoproteins, noneuzymatically catalyze oxidation of unsaturated fatty acids and hence contribute to the development of oxidized flavor. Purified native lactoperoxidase had a catalytic activity on linoleic acid comparable to that of other native hemoproteins but this activity was drastically increased on heat-treatment of the enzyme. Both native and denaturated lactoperoxidase accelerated the development of the expected aldehydes from linoleic acid, which were identified by combined gas chromatography-mass spectrometry. In addition 2-pentyl-furan, propan-l-ol and pentan-l-ol were identified.