Friends who have bought seafood know that after the fresh seafood is slaughtered, even if it is just taken home and put in the refrigerator for a short time, after cooking, the taste is not as fresh and sweet as the live, and the meat quality is not as good as the "Q bomb" when it is fresh.
This is quite different from pork, beef and mutton, which need to be slaughtered and put for a while, and after the process of "aging", the meat is more tender. Why is that?
So fresh seafood
Why doesn't it taste good when you die?
If you want to know why seafood is "not tasty" when it dies, you must first understand what changes have generally occurred after the death of seafood.
Seafood is rich in protein and unsaturated fatty acids, and because it lives in water, it often carries bacteria and other microorganisms in various parts of the body. It is conceivable that after the death of seafood, bacteria and other microorganisms lose the constraints of the seafood's immune system and will multiply rapidly on this "happy land" full of proteins and fatty acids, allowing the seafood to spoil and spoil.
Soon, the enzymes in the seafood will begin to break down the protein, so that the original "Q bomb" tight muscle tissue will be destroyed, become loose and soft, and the taste will deteriorate;
Abundant unsaturated fatty acids are oxidized to produce various odorous substances, such as aldehydes, ketones, and other volatile substances such as isopropylbenzene, styrene, and ethyl acetate;
Myoglobin is oxidized to methemoglobin, which makes the originally pink red seafood gray and brown; The rapid multiplication of bacteria will also cause black and gray spots to appear on the surface of the seafood;
Therefore, once the seafood dies, the meat quality, smell, and color will change quickly, and the color and flavor will decline across the board, and it will naturally not be delicious.
It's actually okay at this point, it's just not delicious. Some seafood releases toxins that are harmful to the human body after death, which is even more dangerous. For example, tuna, mackerel, and sardines are rich in histidine, and if they are not stored properly after death, they are very easy for bacteria to convert histidine into histamine in a high temperature environment.
Histamine can cause food poisoning, causing serious conditions such as rashes, headaches, vomiting, diarrhea and even difficulty breathing, coma, etc. Therefore, if you want to eat seafood safely, you must be cautious in the selection of seafood varieties and avoid those species that are easy to be poisonous or toxin-producing.
Is the freshness of seafood a double-edged sword?
Fresh seafood doesn't even need to add any seasonings, just boiled in plain water, it is extremely sweet, and the fresher the seafood, the more obvious this fresh sweetness.
The strong umami flavor of seafood comes mainly from the abundant "umami amino acids" in the body. "Umami amino acids" refer to a class of amino acids with special umami taste, such as glutamic acid, aspartic acid, phenylalanine, glycine, tyrosine, etc. Among them, the sodium salt of glutamic acid, monosodium glutamate, is the main component of monosodium glutamate. The content of glutamic acid and aspartic acid in seafood is generally very high.
At the same time, there are a large number of nucleotides in seafood, such as adenosine monophosphate, inosinate, and guanylate, and their presence can multiply the taste of umami amino acids such as glutamic acid and aspartic acid, so that the freshness of seafood can be brought to a higher level. In addition, fresh seafood also has a hint of sweetness, which mainly comes from the glycogen in the meat and some amino acids with a slight sweetness, such as glycine and alanine.
Studies have shown that the content of glutamate, inosine monophosphate disodium and adenine nucleotides in marine shrimp and crabs is higher than that in freshwater shrimp and crabs, which is probably one of the reasons why everyone thinks that seafood is more delicious than river fresh.
But these umami substances also seem to be a double-edged sword. When the seafood is alive, the above-mentioned umami substances are constantly produced and accumulated, making the seafood "fragrant to the point of confusion"; And once the seafood is dead, they begin to decompose rapidly, greatly reducing the edibility of the seafood:
When the umami amino acids are decomposed, they release a pungent ammonia smell, which is unpleasant. After the decomposition of some sulfur-containing amino acids, hydrogen sulfide will also be produced, which emits the smell of rotten eggs;
Glycogen, which once gave the meat a sweet taste, also accelerates its decomposition, releasing lactic acid, giving the seafood a spoiled sour taste;
There is also a substance found in seafood called trimethylamine oxide, which can bring a fresh and sweet taste to seafood, but after the seafood dies, it will quickly decompose and produce trimethylamine and dimethylamine, which will give seafood a strong fishy smell.
The combination of the above-mentioned foul, sour, and fishy smells will make the dead seafood smell and turn away.
Craving for fresh seafood
How to pick, how to store?
If you want to eat fresh seafood, the most convenient way is to sit directly on the fishing boat and eat it while fishing; The next best thing to do is to wait on the shore and buy seafood that has just been caught by the fishing boat. But if we don't live in coastal areas, these ways are not convenient for modern people, and we can only go to the market or supermarket to buy. Then you will definitely be able to use the following tips:
1. Preferred live seafood. It is important to note that in live seafood it is also necessary to pay attention to their actions and reaction speeds. It can be lightly touched with a fish copy, whether it is fish, shrimp, crab or shellfish, those with faster action speed and quick response to external stimuli tend to have higher freshness.
2. Look at the quality of the meat. The meat is firm and elastic, and the tentacles are not sticky, indicating that the protein has not been broken down and the freshness of the seafood is higher.
3. Weigh the weight. When seafood dies, nutrients such as protein are broken down, which can reduce the weight of the seafood. Therefore, it is preferred that those of the same size seafood that are more "pressing" tend to be fresher.
4. Try not to buy too much, it is best to buy and eat now. In case you can't eat all the seafood you bought at home, you can also divide it into small portions and store it in the freezer compartment of the refrigerator. In this way, take one serving at a time to thaw, you can avoid the effect of repeated thawing and freezing on the quality of the meat.
By the way, finally a way to save money: quick-frozen seafood has almost no loss of nutrition compared to fresh seafood, and the freshness is also better maintained. The disadvantage is that seafood has a large water content, and it is easier to produce ice crystals during the freezing process, which affects the elasticity of the meat. However, considering that the quick-frozen seafood is easy to store and the price is much cheaper than that of fresh seafood, it is still worth recommending. For some seafood that does not have much impact on the taste after freezing, such as prawns, you can choose to freeze.
During the Mid-Autumn Festival, everyone takes this selection strategy to the supermarket to choose seafood for their families, and be prepared.
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