Effect of heat treatment on protein oxidation in pig meat.

We investigated the oxidative mechanisms and identified the target protein induced by heat treatment. The study was carried out on M. longissimus thoracis from Galia and Redone pigs. Post mortem metabolic parameters and drip loss were determined. Heat treatment was performed at 100 °C for 10 and 30 min. Physicochemical state of the protein, TBA-RS and Schiff bases were assessed. Protein aggregates were evaluated and the protein target of oxidation studied. Muscles from Galia had higher residual glycogen and drip loss. Heat treatment increased surface hydrophobicity, carbonyl, protein aggregate and Schiff bases and TBA-RS whatever the treatment time. Immunoblotting revealed oxidized myosin, oxidized actin and high molecular weight proteins after 30 min cooking. Oxidation products were significantly correlated with drip loss, suggesting a possible reduced ability of oxidized proteins to retain water. Moreover, residual glycogen was positively correlated with oxidized myosin, suggesting a possible role of glycogen as a glucose donor.