A model system was conducted to characterize the interaction between lipid autoxidation and enzyme-catalyzed oxidation in dry-cured bacon. This involved the use of a hydroxyl radical (HO•) generating system and the extraction and purification of lipoxygenases (LOX) from pork belly. The results showed that LOX activity rapidly (P < 0.05) increased during the curing of dry-cured bacon. This may be because of the hydroxyl-radical-mediated oxidation from LOX-Fe(2+) to LOX-Fe(3+), which activates LOX. In addition, experiments of the model system also showed that LOX activity could be inhibited by increasing the substrate concentration, although substrate type and concentration had no effect on autoxidation. Moreover, LOX enzyme-catalyzed oxidation and autoxidation could act synergistically to promote lipid oxidation irrespective of the substrate (linoleic or arachidonic acid). These results provide useful information for regulating lipid oxidation during the production of dry-cured pork products.
Keywords: autoxidation; dry-cured bacon; enzyme-catalyzed oxidation; lipid oxidation.
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