What is the change in stiffness of fresh fish when it is preserved

The change in stiffness of fresh fish during preservation is due to chemical reactions in the body of the fish after death. Specifically, after the fish dies, the glycogen and enzymes in the body are broken down to produce lactic acid, which lowers the pH of the fish from about 7 to to. At the same time, creatine phosphate and adenosine triphosphate also begin to break down, which leads to a decrease in ATP levels in the muscles of the fish.

When ATP levels drop to a certain level, myosin and actin, which make up myofibrils, begin to contract and lose their stretchability, which makes the fish body appear stiff.

This stiffness begins shortly after the fresh fish is caught, usually starting minutes or hours after death and lasting from hours to tens of hours before gradually softening. In the stiff stage, the freshness of the fish body is good. However, over time, the fish will undergo further changes, including rancidity, spoilage, and dehydration, which can affect the quality and freshness of the fish.

In order to maintain the freshness and quality of fresh fish, some measures can be employed, such as immediately refrigerating the fish carcass, removing excess water, sealing the package, etc. In addition, there are different preservation methods for different types of fresh fish, such as salting, drying, smoking, etc.

Changes: Soon after the death of the fish, there are more complex biochemical changes in the muscle tissue.

Make it stiff. Fish stiffness generally occurs from 10 minutes to 4 5 hours after death. Stiffness starts from the back muscles, and gradually spreads throughout the whole fish body, in a stiff state, when holding the fish head with the hand, the fish tail generally does not bend down, and the finger pressure on the muscles does not show the indentation, the fish mouth.

Close tightly and operculum tightly closed. Stiffness lasts for a few minutes and can last for several days. The rate at which stiffening occurs varies depending on the type of fish, the size of the fish, the method of harvesting, the temperature at which it is kept, and the method of handling. This is because animal meat contains glycogen more than fish meat.

more, so the stiffness of the two is different. The lower the temperature of the fish, the slower the stiffness occurs after death, and the longer the stiffness is maintained. The freshness of the fish in the stiff stage is good.

1. If you want to keep fresh fish, first we can use plastic wrap to control the fish and wrap it in a plate after the water is clean, and then put it in the refrigerator.

2. If you want to keep fresh fish, we can also choose to put more ice cubes and lemon next to it. Keep it cold, and lemon can also be a good way to get rid of the fishy smell.

3. If you want to keep the fish fresh, we can also choose to put the fish in the crisper box, so that it is well sealed, and we can put it in the refrigerator in the future.

4. Or we can also take out the fish and put it in the water, and then marinate it with salt, so that the fish can also maintain its freshness.