本研究之目的旨在探討比較高畜黑豬 (KHAPS Black Pig) 背最長肌 (Longissimus dorsi) 與腰大肌 (Psoas major) 屠後72小時期間calpain、desmin及嫩度之變化。本試驗使用十一月齡高畜黑豬 (50% Meishan及50% Duroc)，平均活重約100−110公斤之女豬 (n = 10)，依屏東市台灣農畜產工業股份有限公司之標準作業程序屠宰後，屠後30分鐘內取下屠體兩側背最長肌 (第5至13肋間) 及完整腰大肌，個別分切成七等份後真空包裝置於5oC貯存，屠後第0 (約為屠後30分鐘)、3、6、12、24、48及72小時採樣，分析pH值、calpain活性及desmin降解之變化。另外， 屠後第24及72小時測定截切值 (Shear force value)。結果顯示，屠後72小時期間，高畜黑豬背最長肌之pH值、μ-calpain活性、desmin含量及截切值下降速率均較腰大肌為快。所以，高畜黑豬屠後72小時期間因背最長肌之μ-calpain活化快，導致其desmin降解及肉質嫩化速率較腰大肌為快。

The objective of this study was to compare the postmortem changes in Longissimus dorsi (LD) and Psoas major (PM) muscles of KHAPS Black Pigs (50% Meishan x 50% Duroc) (n = 10). Both sides of LD (5-13 ribs) and PM were removed from the carcasses in ~30 min postmortem, cut into seven equal portions, vacuum-packed individually, and stored at 5°C for 0 (30 min postmortem), 3, 6, 12, 24, 48 and 72 hours. At the end of each storage period, muscle was sampled and analyzed the pH value, calpain activity and desmin content. Samples from postmortem 24 and 72 hours were also used to determine shear force. The results showed that rate of postmortem pH, μ-calpain activity and desmin content decreased more rapidly in LD than in PM samples. The decrease in shear force were also faster in LD than in PM samples. Therefore, our results suggest that the μ-calpain activation and autolysis is more rapid in LD muscle than in PM muscle during early 72- hours postmortem storage period, leading to a faster desmin degradation and meat tenderization occurred in LD.