Abstract: The Longissimus dorsi muscles of 20 pigs were measured for pH and the expression levels of integrin, vinculin and talin at 45 min, 3 h, 9 h, 12 h and 24 h postmortem, as well as drip loss, and the relationships among them were analyzed. The results showed that the drip loss and talin expression level in the high pH group (pH45 min ≥ 6.00, n = 6) were lower than those in the low pH group (pH45 min ≤ 5.78, n = 14), while the expression levels of integrin and vinculin were higher than those in the low pH group. pH and the expression levels of integrin and vinculin had a negative correlation with drip loss, while talin expression level had a positive correlation with it. pH and the expression levels of integrin, vinculin and talin respectively accounted for 77%, 41%, 44% and 34% of the variation in drip loss. The above results indicated that changes in pH and cytoskeletal protein expression both affected the water-holding capacity of pork, and the decrease in pH had a greater effect on pork water-holding capacity than did the degradation of cytoskeletal proteins. pH could affect the integrity of the cytoskeleton and thus the water-holding capacity of pork. pH at 45 min postmortem can be used to predict the drip loss of pork during postmortem aging.

Key words: pH; integrin; vinculin; talin; water-holding capacity