Characterisation of broiler breast and leg meat for further processing

It is well known that during the production of further processed poultry meat products such as breaded patties, the quality characteristics of raw meat, mainly represented by the chemical composition and functional properties, play a key-role in the final quality of the products. A study was conducted in order to evaluate the quality characteristics of different types of raw meat used for the commercial preparation of breaded patties: ground breast and leg meat as well as a mix of ground breast/leg meat (breast:leg 2:1) which is commercially used for the preparation of the meat batters (by mixing the ground breast/leg meat with additives and water) and subsequently for breaded products manufacturing. Furthermore, the meat was obtained from broiler chickens fed on two diets containing animal fat (AF) or vegetable oil (VO) as lipid source. The experiment was replicated two times in a single major Italian processing plant considering during each trial two homogeneous flocks of male broiler chickens (Ross 508, 54 days old) differing only by lipid source of the diet which consisted in animal fats (cattle tallow and pork lard, AF) or vegetable oils (sunflower and soybean oils, VO). Breast and leg meat were roughly grounded and subsequently mixed (breast:leg 2:1) for the preparation of a mix used for further processing. Ground breast, leg and mix products were sampled and used to prepare meat patties of about 70g which were analysed for colour (L*a*b*), pH, cooking loss, AK-shear values after cooking, moisture, protein, lipid and collagen contents as well as induced TBARS. The data were analysed by two-ways ANOVA (GLM/SAS procedure) by testing both type of meat (breast, leg and mix product) and lipid source of the diet (AF and VO) as main factors. With regard to the influence of type of meat, all considered parameters were significantly different among groups with the exception of moisture content. In comparison with leg meat, breast meat presented lower L* (53.25 vs. 56.25; P<0.001), a* (3.56 vs. 9.34; P<0.001) and b* (6.58 vs. 10.36; P<0.001) values, lower pH values (5.92 vs. 6.35; P<0.001), lower cooking loss (24.42 vs. 28.29%; P<0.001) and higher shear force (1.63 vs. 1.84kg/g; P<0.01). About chemical composition, breast meat presented higher protein content (24.28 vs. 20.00%; P<0.001), while lower lipid (1.55 vs. 5.80%; P<0.001) and collagen (1.14 vs. 1.95%; P<0.001) contents. Finally leg meat showed higher susceptibility to oxidation (Fig. 1). As expected, mix product presented intermediate values.Concerning the effect of dietary lipid source, the results indicate that the dietary use of VO determined higher cooking losses (25.13 vs. 27.26%; P<0.001) and shear values (1.66 vs. 1.49kg/g; P<0.05) in meat products with respect to the AF diet. Moreover meat from birds fed VO diet were darker (L*, 54.37 vs. 55.87; P<0.001), more yellow (b*, 6.80 vs. 6.47; P<0.05) and red (a*, 9.36 vs. 8.33; P<0.001). Finally, ultimate pH and chemical composition did not vary significantly. These results also evidenced that dietary lipid source can strongly influence product appearance, texture and protein functionality. In conclusion, it was found that differences in dietary lipid source as well as the type of meat can strongly affect the final characteristics of meat products for further processing.