Collapse of the endogenous antioxidant enzymes in post-mortem broiler thigh muscles triggers oxidative stress and impairs water-holding capacity.

Abstract

This study was conducted to investigate the effect of the collapse of the endogenous antioxidant enzymes, namely, catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in post-mortem (PM) chicken thigh muscles on the extent of lipid and protein oxidation and the functionality of the muscle in terms of water-holding. To fulfil this objective, the samples were divided into two treatments: one group of muscles (n = 8) was subjected to delay cooling (DC) (at ~ 37°C for 200min PM) and then stored at 4°C for 24h. The second group (n = 8) was subjected to a normal cooling (NC): samples were immediately chilled at 4°C for 24h. DC samples presented a decrease in 16% of CAT, 25% GSH-Px and 20% SOD activity in relation to NC. Consistently, an increase of 36% of total carbonyl, 15% of Schiff bases and 27% of TBA-RS and 14% of tryptophan depletion was observed in DC samples, as compared to NC. The results suggested that DC challenged muscles to struggle against oxidative reactions, consuming endogenous antioxidant defenses and causing protein and lipid oxidation which in turn affect the quality and safety of chicken meat. These results emphasize the role of PM oxidative stress on chicken quality and safety. Antioxidant strategies like fast cooling may be combined with others (dietary antioxidants) to preserve chicken quality against oxidative stress.