Effect of lean meat proportion on the chemical composition of pork

The objective of this work was to verify the effect of the lean meat proportion on the chemical composition of the meaty parts (loin and ham) of pork. A total of 116 finishing hybrid pigs commonly used in the Czech Republic were fattened for this purpose. The pigs were divided according to the lean meat proportion criterion into 3 groups, i.e. more than 60.0%, 55.0-59.9% and 50.0-54.9%. Representative muscle samples were taken from the right halves of these pigs. They were then homogenised and submitted to chemical analysis. The results of the measuring showed that the values of the water content, intramuscular fat (IMF), crude proteins, and ash matter ranged in the loin between 72.50-72.80%, 1.56-1.96%, 23.20-23.40%, and 1.37-1.40%, respectively, and in the ham between of 70.43-71.59%, 3.52-4.26%, 21.67-21.95%, and 1.42-1.56%, respectively. The ascertained values of the water content and crude proteins with regard to the increasing lean meat proportion in the carcasses did not show any developmental tendencies. As for the content of IMF, it was determined that the higher was the lean meat proportion, the lower was the IMF content. Concerned of sensoric quality traits it means that pork meat from supermeaty hybrid pigs shows lower quality. Concerning the content of ash matter, it was observed that the ash content increased with an increasing lean meat proportion. In the carcass part of the musculus longissimus lumborum et thoracis (MLLT), it was demonstrated that the higher was the lean meat proportion, the lower was the content of amino acids - threonine, isoleucine, lysine, aspartic acid, serine, and proline. From point of the production of exceedingly meaty pigs (over 60%), it can be expected a worse nutritional pork meat value. In the carcass portion of the musculus semimembranosus (MS), the contents of valine, isoleucine, phenylalanine, lysine, serine, proline, and glycine increased with an increasing lean meat proportion. Within the framework of statistical evaluation of differences between the groups, the values of IMF ((P ≤ 0.01) in MLLT, water content, IMF, ash matter, threonine, valine, phenylalanine, lysine, aspartic acid, serine, glycine, and alanine in MS were highly significant ((P ≤ 0.05; (P ≤ 0.01 and (P ≤ 0.001).