Lipídios totais, textura e perda por cocção de cortes de carne bovina de diferentes marcas comerciais.

Background: The beef production chain has undergone wide and profound changes to meet final consumer demands. Additional evaluation criteria, as well as sensorial quality, were investigated, which contemplated nutritional composition, presentation and production method. One of the most important traits in beef quality evaluation is fat level and its stability, as this is associated with product colour and acceptability. The amount of fat directly affects quality, as it influences lipid oxidation, and may cause rancid odours and unacceptable flavours. Oxidative stability depends, among other factors, on the concentration of polyunsaturated fatty acids. The study was conducted to analyze the relationship between total lipid content, texture and cooking loss of three cuts of beef (short loin, rump and rib) of five brands (A, B, C, D and E), commercialized in Porto Alegre City, Rio Grande do Sul State, Brazil. Materials, Methods & Results: Samples of short loin (Longissimus), rump (Biceps femoris) and rib (Intercostal) were collected in a large supermarket chain. Laboratory tests were performed to determine total lipids, texture and cooking loss. The experimental design was completely randomized, factorial arrangement with five brands: two belonged to breed Associations (A) and (B); one was Uruguyan (C); one a regional abattoir (D) and the last a regional hypermarket chain (E), all with three cuts and seven replicates. Interaction was observed between brands and cut, the rib presented significant difference for the different brands for total lipids content (4.61, 2.12 and 1.98% for brands B, E and D, respectively). A significant correlation was found between lipid level and texture (r = 0.41). Longissimus and Biceps femoris differed (P < 0.05) in total lipid content from Intercostal for all brands, and for shear force, Longissimus and B. femoris differed from Intercostal (1.94, 1.87 and 2.92 kgf respectively) with brand D differing from A (2.62 vs 1.76 kgf). Loss during cooking differed (P < 0.05) between the cuts evaluated (16.17 and 20.77% for short loin and rump, respectively). No significant difference was found between brands. Discussion: The rib, as it shows high variability, showed highest lipid levels, and samples from British-type animals, which have high deposition of intramuscular fat (brand B), had the highest values. Marks D and E are mainly from crossbred and zebu type animals, and therefore have lower total lipid levels in the meat. The rib showed the greatest force needed to tear muscle fibers, since it has great variation in the amount of collagen. However, in all cuts analyzed, texture can be regarded as "very tender", probably due to the high quality of the cuts and marks used. Mark A, which commercializes mainly young animals, an important factor affecting texture and tenderness, showed lower shear force while the other marks, mainly C and D, as they sell older animals, showed poorer meat quality. It is important to differentiate between muscle types for water retention as this influences succulence during mastication and therefore the acceptability of the meat by the consumer. The increased water retention capacity, caused by the presence of fat, reflects positively on cooking loss. Cuts with higher and lower cooking loss were, respectively, the rump and loin. Therefore, for these parameters, there are clear differences in quality between the beef brands sold in the city of Porto Alegre. [ABSTRACT FROM AUTHOR]