Protein and lipid oxidation in Parma ham during production.

Lipid oxidation adds to the characteristic flavor of dry-cured products, but the role of protein oxidation in the production of such meats is unknown. Lipid and protein oxidations in biceps femoris (BF) and semimembranosus (SM) muscles were evaluated throughout the production period of Parma ham (0-13 months). Lipid oxidation, determined as primary and secondary lipid oxidation products (POV and TBARS), and protein thiol loss commenced immediately without any lag phase and preceded the initiation of protein radicals and protein carbonyls, which increased after a lag phase of 3 months. TBARS reached a maximum value of 2.5 mg MDA/kg dry matter in SM after 1 month and leveled off at 1 mg MDA/kg dry matter in both SM and BF between 6 and 12 months. Loss in protein thiols proceeded similarly for SM and BF from initial ∼50 to ∼27 nmol/mg protein after 6 months and stayed constant. Gel electrophoresis showed that myosin was lost primarily by proteolytic degradation and not by polymerization through protein disulfides. Overall, oxidation accelerated during the first stages of production but stabilized toward the final stages of maturation.