The relationship between protein changes in porcine longissimus muscle at different courses of meat tenderisation

Among many factors affecting meat tenderness, a special role is attributed to proteins. The aim of this study was to analyse relationships between the tenderness of meat and changes in the abundance of muscle tissue and centrifugal drip proteins as well as in a value of the simple assessment criteria of the glycolysis process in porcine longissimus thoracis et lumborum muscles. All of them were used for describing conditions associated with tenderisation process and predicting tenderness. For analysis of protein changes in the muscle tissue (45 min, 48 and 144 h pm) and in its centrifugal drip (48 and 144 h pm), SDS-PAGE technique was applied. The progress of glycolysis was evaluated on the basis of pH value as well as the electrical conductivity (EC) measurements. Warner–Bratzler shear force assessment (48 and 144 h pm) was involved for the evaluation of tenderness. Comparisons concerned four groups of muscles characterised by different courses of tenderisation. The study showed that proteolysis was closely related to the process of glycolysis in muscles which was linked with genotype of pigs. The single correlations between protein changes and meat tenderness varied in the selected groups of muscles. It was possible to make very precise predictions of the meat tenderness using canonical correlation analysis. Based on the percentage participation of the selected muscle tissue and centrifugal drip proteins and measurements of pH and EC at specified time pm it was possible to predict tenderness with a very high probability, even 89%.