Comparison of meat quality characteristics and oxidative stability between conventional and free-range chickens.

The aim of this research was to evaluate quality traits and oxidative stability of meat products from free-range (FR) and conventionally (C) raised chickens as they actually reach consumers in the Italian retail market. Free-range female and male chickens (n = 1,500 + 1,500), medium growing ISA strain, were raised under commercial conditions for 56 (1.8 kg of live weight) and 70 d (3.1 kg of live weight), respectively; C female and male birds (n = 5,000 + 5,000) were a fast growing hybrid (Ross 708) and were separately raised for 39 (1.9 kg of live weight) and 50 d (3.1 kg of live weight), respectively. A total of 96 chickens (equally divided by production system and sex) were slaughtered in 2 separate sessions to obtain the main 2 commercial categories (rotisserie and cut-up, respectively). After slaughtering, 12 carcasses of each treatment group were randomly selected and used to assess quality properties, chemical composition, and oxidation stability of breast and leg meat. The C birds had dramatic higher carcass and breast meat yield, whereas FR had higher wing and leg yields. The FR birds exhibited higher water holding capacity in both breast and leg meat. Although shear force did not differ in breast meat, legs from FR birds were tougher. Fatty acid composition of FR breast and thigh meat of both categories were characterized by a higher polyunsaturated fatty acid n-6-/n-3 ratio. In general, a low lipid oxidation level (peroxide value < 1.3 mEq O2/kg of lipid and TBA reactive substances < 0.2 mg malondialdehyde/kg of sample) was found in breast and legs, regardless of the commercial category. However, the C system significantly increased peroxide value in rotisserie thigh meat, whereas FR led to a significantly higher TBA reactive substances in breast meat. Our results demonstrated that free range can modify the properties of chicken meat and also highlighted the importance of the bird genetic background to select nutritional strategies to improve meat quality traits and oxidative stability in poultry.

The use of sodium bicarbonate for marination of broiler breast meat.

This study aimed to evaluate marination performances and the effect on meat quality traits of sodium bicarbonate, used alone or in combination with sodium chloride, when compared with sodium trypolyphosphate by using advanced analytical tools, including low-field nuclear magnetic resonance and differential scanning calorimetry. In total, 140 samples (cylindrical shape of 1 × 4 cm size) were obtained from a batch of 24-h postmortem broiler breast meat (Ross 708, females, 47 d old). Six of the groups were used for subsequent marination treatments, whereas the last group was kept as a nonmarinated control. Samples were subjected to vacuum tumbling in a special equipped laboratory rotary evaporator with a 12% (wt/wt) water:meat ratio using 6 marinade solutions: 7.7% (wt/wt) NaCl (S); 2.3% (wt/wt) Na(4)O(7)P(2) (P); 2.3% (wt/wt) NaHCO(3) (B); S and P; S and B; S, P, and B. Samples marinated with bicarbonate alone or in combination (B, SB, and SPB) significantly increased (P < 0.05) the meat pH by approximately 0.7 units compared with that of the control, whereas phosphate alone or in combination with salt increased (P < 0.05) the pH by 0.2 units. The combination containing all of the ingredients (SPB) produced the highest marinade performances; however, SB was able to guarantee a better marinade uptake and water retention ability with respect to that of SP. According to low-field nuclear magnetic resonance, the combined use of B and P with S determined a remarkable increase in proportion of entrapped water into the myofibrillar spaces, while the extramyofibrillar water fraction was not modified. Moreover, water gain following marination does not correspond to an increase in the freezable water amount, as detected by differential scanning calorimetry. In conclusion, B is a very promising marinating agent, and it can be exploited to develop processed poultry products with no added phosphates to match the request to avoid the nutritional drawbacks recently indicated with the use of phosphates.