Phosphorylation of sarcoplasmic and myofibrillar proteins in three ovine muscles during postmortem ageing |
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| Authors: | Ying WANG Xin LI Zheng LI Man-ting DU Jie ZHU She-qi ZHANG De-quan ZHANG |
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| Institution: | 1. Laboratory of Biomechanics and Engineering, Institute of Biophysics and College of Science, Northwest A&F University, Yangling 712100, P.R.China;2. Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing 100193, P.R.China |
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| Abstract: | This study aimed to examine changes in phosphorylation of sarcoplasmic and myofibrillar proteins from longissimus lumborum, semitendinosus, and psoas major muscles during postmortem ageing for 5 d. These sarcoplasmic and myofibrillar proteins were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and stained with phosphorous and protein specific stains. Myofibril fragmentation index, pH, the content of lactic acid and the relative activity of μ-calpain in three ovine muscles were measured. These results showed that the relative phosphorylation level of sarcoplasmic and myofibrillar proteins of psoas major muscle were lower compared with longissimus lumborum and semitendinosus muscles (P<0.05). The pH of psoas major muscle was the lowest at 0.5 h postmortem, and the highest after 12 h postmortem (P<0.05). In addition, the relative activity of μ-calpain was higher within 5 d postmortem and myofibril fragmentation index was higher after 1 d postmortem in psoas major muscle than those of longissimus lumborum and semitendinosus muscles (P<0.05). The sarcoplasmic protein phosphorylation may regulate the rate of pH decline to influence the μ-calpain activity and then proteolysis of proteins consequently. This study gives a new perspective of the mechanism of postmortem meat tenderization. |
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| Keywords: | Correspondence ZHANG De-quan Tel: +86-10-62818740 ovine muscle protein phosphorylation μ-calpain myofibril fragmentation index |
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