Comparison of the thermal characteristics of connective tissue in loose structured and normal structured porcine M. semimembranosus

The aim of the present study was to characterise the thermal properties of connective tissue in loose structured porcine SM muscles in comparison to normal looking SM muscles and to see whether the meat quality traits were related to the properties of connective tissue. Samples from the muscles with loose structure and light colour were selected by visual assessment and normal looking SM muscles were used as a control (n = 25 loose structured + 25 control). The loose structured muscles had lower ultimate pH (pHu) than the control muscles. The onset and peak temperatures of thermal shrinkage of intramuscular connective tissue (To and Tp, respectively) in loose structured muscles were similar to those of control muscles when the full set of data (25 loose structured + 25 control) were analysed. When the To and Tp data from muscles the exhibiting ten lowest and ten highest pHu values were analysed, the low pHu muscles (all classified as loose structured) had lower To and Tp than the high pHu muscles (all classified as control) (p < 0.05). Drip loss of loose structured SM muscles (11.1%) was dramatically higher than that of control muscles (3.9%). Collagen content and collagen solubility were similar in loose structured and control muscles. It seemed that changes in the properties of intramuscular connective tissue were more easier found in porcine SM muscles with low pHu than in SM muscles with high pHu.