Influence of ultimate pH on the physicochemical and biochemists parameters associated tenderness of the meat of Bos indicus cattle

Abstract

The main goal of the worldwide beef chain is to attend the consumer's demands, who are becoming increasingly informed and demanding for meat quality, animal welfare, and sustainability. In this scenario, Brazilian production has the challenge to be competitive, where the use of technology is a path to sustainability, ethics, and profitability. However, there is a lack of information in the national production about quality limits and sensory resources of beef. One of these parameters is the final pH (pHu) of the post-mortem muscle, widely used as a predictor of meat quality. Brazil is the largest exporter of beef in the world, however, it does not have a deeper knowledge about the pHu of post-slaughter muscle and its impact on meat quality. Thus, the goal of this project is measuring the pHu (48 hours after slaughter) and associate it with the biochemical changes and with the meat quality attributes, mainly tenderness. For this purpose, 1,200 animal of Nellore breed (Bos indicus), uncastrated males, 36 to 42 months old, 4 to 6 incisive teeth, fed on pasture or in the feedlot will be used. Over a year, four quarterly collections of Longissimus dorsi muscles (counter-archive) will be performed in a large refrigerator, in order to ensure the representation of national meat. At each refrigerator visit, 300 cattle reach the ultimate pH (48 hours after death) of carcasses which are determined for classification in three pH ranges: 5.4 to 5.8 (low); 5.8 to 6.2 (intermediate) and> 6.2 (high). Twenty samples of each pHu range will be used for the shear force, physicochemical strength (myofibrillar fragmentation index, MFI) and total collagen and solution content analyses. Five samples of each pHu range and in five different time points of post-mortem (30 min, 6 h, 24 to 48 h) will be used in SDS-PAGE and immunodetection analyses. These analyses will be performed to quantify the caspases 3/7 and identify anti and pro-apoptotic components. The data collected will provide new insights, which could be applied in meat quality programs and provide new advances for Brazilian Meat Science. (AU)