Effects of the rearing systems on the oxidative stability of chicken meat

The aim of this research was to evaluate the effect of two different rearing systems (free-range and conventional intensive systems) on the oxidative stability of chicken breast and leg meat, currently marketed within different product categories (rotisserie and cut-up carcasses). Free range (FR) female and male chickens, belonging to medium growing Isa strain, were separately raised for 56 and 70 d, respectively; conventional (C) female and male birds were a fast growing hybrid (Ross 708) and were separately raised for 39 and 50 d, respectively. Female and male chickens were slaughtered into 2 separate sessions, in order to obtain the main two commercial categories (Rotisserie and Cut-up, respectively). After slaughtering, 15 carcasses of each group were randomly selected and used to assess oxidation stability of both breast (skinless) and leg meat (with skin). Each sample was removed from the carcass, minced, packed in plastic bags covered by aluminum foil under vacuum and kept at –18°C until analysis. Lipid content, peroxide value (PV) and thiobarbituric acid reactive substances (TBARs) were determined. In both categories, rearing system did not significantly affect the lipid content of leg meat (10.4-11.6%), but the conventional system led to a significantly higher lipid content (0.9-1.7%) in breast meat in both Rotisserie and Cut-up categories. In general, a low level of PV (0.79-1.06 and 0.30-1.29 meq O2/Kg of lipid in breast and legs, respectively) and TBARs (0.06-0.19 and 0.10-0.13 mg MDA/Kg of sample in breast and legs, respectively) were found, regardless of the commercial category. However, the conventional system significantly increased PV in Rotisserie leg meat, whereas TBARs was significantly higher in Rotisserie breast meat obtained with the FR system. In the Cut-up category, no significant effects on the oxidation stability of leg meat, were detected, but the FR system led to a significantly higher TBARs content in breast meat. Despite these differences, it can be concluded that the two different rearing systems led to a low, overall oxidation level in both poultry breast and leg meat, which ensures their quality and safety from the consumer health standpoint