Why meat shrinks when grilled

In this article, the protein contained in meat
Myofibrillar protein (coagulates around 45-50°C)
Sarcoplasmic protein (coagulates around 56-62°C)
Collagen (shrinks to 1/3 at around 65℃)

Thus, collagen contracts very strongly above 60°C.


chicken meat
Fish meat (cod)
myofibrillar protein
68 51 62 79
sarcoplasmic protein
17 20 33 21
Fascia/fascia (mainly collagen)
15 29 5 3
The table above shows a comparison of the composition ratio of protein by tissue of meat by animal. Among them, the ratio of fascia/muscular membrane (collagen) is higher in beef and pork than in chicken and fish meat.

Therefore, the rate of meat shrinkage due to heating such as grilled meat is greater for beef and pork than for fish and chicken. Pork, in particular, has a lot of collagen and tends to shrink, so it warps when grilled.

For this reason, you can prevent warping by tapping the meat or piercing the muscles at the boundary between lean and fat with the tip of a kitchen knife.