Is frozen fish kept fresh for nutrition?

Recently, the issue of live fish has attracted much attention, and when the live fish is missing, the most disturbing feeling is frozen fish.

In the matter of "eating", there are always roads leading to Rome. When the live fish can not be bought, the chopsticks that eat the food also extend to the frozen fish that have not disappeared. Who called the fish from ancient times to the present is the big dishes on the table, holidays, weddings and funerals are few, but there are always fish in the banquet. There is no way, whether it is to satisfy the appetite, or want to get rich nutrition, fish in the meat family is often "high livestock".
But some people wonder if the nutritional value of frozen fish is higher than that of live fish.
Freezing is an important way to preserve
Compared with poultry and cattle and cattle, the muscle tissue of the fish has more water content, higher soluble protein content, unsaturated fatty acid, less natural immune substances and more bacteria attached to gills and viscera. The fish is weak alkaline after death, which is more suitable for bacterial growth, and is more likely to be spoilage. So the witty eating ancestors invented the ice fish and the frozen fish in order to bring the distant fish to their home table and let more people taste the beauty of different kinds of fish.
Ice fresh fish is a way of cooling with ice, which lengthened the rigidity of fish after death, which is equivalent to "freeze" the physiological state of fish cells at the moment of death. Therefore, the taste and taste of frozen fish are similar to those of live fish.
But frozen fish can only be preserved for a few days, and we want to eat fish species from distant waters. We have to rely on a longer and more stable way of preservation. Under freezing conditions, enzyme activity and microbial growth are suppressed. The shelf life of fish is also greatly extended, usually for several months. So the emergence of frozen fish is just to enable us to taste fish species in remote waters.
Freezing does not affect the nutritional value of the core
But for all of us, what is most concerned is what happens after frozen fish compared with live fish.
First of all, from the taste, frozen meat does not contain fresh fish. This is mainly because in the freezing process, the water freezing in the fish is frozen into ice crystal, which causes the frozen denaturation of the fish protein and a series of changes in physical and chemical properties, including the changes in the spatial structure and hydrophobicity of the protein, the decrease of the gel and water retention, the decrease of the content of the salt soluble protein, the decrease of the activity of ATP enzyme and so on. The quality and taste of fish declined.
Secondly, from a nutritional point of view, a frozen fish of the same species does lose a part of its nutrition. Because when fish are frozen, the water in the myofibrils of the fish will form ice crystals, but they can not be polymerized with the protein molecules at the time of thawing, and they can not be fully absorbed into the fish. The loss of this juice is accompanied by the loss of soluble nutrients such as soluble proteins, salts and vitamins in fish. However, this loss does not affect the core nutritional value of fish. Because if this loss is also more true, it has to remind you that in fact, the living fish in the temporary breeding process, affected by the local water environment oxygen, temperature, pH value, excreta accumulation and fishing caused by the fish body damage and other factors, will also appear the quality of the decline, the same loss of nutrition.
Therefore, compared with live fish, frozen fish lose their mouthfeel, but there is no obvious difference in nutritional value. More importantly, unless you go to the seaside for vacation, most of the live fish are mostly cultured freshwater fish. And deep-sea fish with higher nutritional value are basically frozen. Therefore, the nutritional value of fish depends on the variety of fish, not simply judging from live fish. For the sake of live fish, abandoning the deep-sea frozen fish is not worth the candle. It is better to treat live fish and frozen fish equally.
The nutritional advantage of the fish
In fact, both live fish and frozen fish are delicious and nutritious ingredients that are indispensable to the diet. Because the nutritional advantages of fish have always been praised.
Most fish accounted for less than 5% of fat, and protein content was as high as 15%-20%. The pork consumed by the Chinese people accounts for 37% of the average fat and only about 13.2% of the protein. Moreover, the fat in poultry meat is mainly saturated fat, too much intake is likely to increase the risk of cardiovascular and cerebrovascular diseases. Fish is rich in unsaturated fatty acids, helps to reduce blood lipids, reduce cholesterol, protect cardiovascular and cerebrovascular health.
For pregnant women and infants, fish is a good thing. Especially for some deep-sea fish, polyunsaturated fatty acids, such as the famous DHA, are of great benefit to brain development. In addition, fish are also rich in vitamin A, D, E and other nutrients that human body needs.