Can you still eat frozen shrimp when it turns black, and the reason why shrimp turns black after tha

Will it be poisoned if you eat it after the shrimp head turns black? A lot of people think wrong, and today I will tell you.

Nutrition Classroom.

01-06 08:03Top 100 creators, high-quality creators.

Concern. When buying vegetables in the market, we often see some "**" shrimp, they don't seem to be so fresh anymore, and the shrimp heads have turned black.

Some people never buy this shrimp, even if they are cheaper. But there are also many people who love to buy this kind of shrimp, and they think that since it can be sold, it is naturally edible, so it is good to cook it quickly.

In fact, in daily life, it is very common for shrimp with black heads to turn black. For example, when you take out the frozen shrimp from the refrigerator, basically the shrimp heads have turned black. But I believe everyone knows that as long as the shrimp is stored in the freezer well, the shrimp can still be eaten with confidence, at most, the taste will be worse.

The reason why it turns black is because there is a substance called tyrosine in the shrimp head, which slowly reacts into melanin and pheomelanin. Although the longer the shrimp is stored, this black color is indeed more likely to appear. But this is just an enzymatic reaction, and it has nothing to do with whether the shrimp is fresh or not, and the produced melanin and pheomelanin are not harmful substances.

In other words, as long as everyone keeps it properly, even if the shrimp head turns black, it will be fine, and it can still be eaten with confidence. Shrimp that are really stale will have the phenomenon of shrimp head separation, shell meat separation and shrimp meat softness.

In addition, many fans often ask us: Can you eat shrimp heads? Ask this question to people in different regions and you may get different answers.

The vast majority of people in most areas don't eat shrimp heads, but if you ask people in Chengdu, they will basically tell you that we eat shrimp heads.

It has to be admitted that shrimp has the ability to enrich harmful substances such as heavy metals in the living environment, and it is mainly concentrated in the head. Therefore, eating shrimp heads is indeed likely to have a safety risk.

However, the heavy metals in shrimp heads are actually more than water and feed. And most of the shrimp that everyone can buy now are farmed species. As long as it is a regular farming, the water quality and feed basically do not contain harmful substances such as heavy metals, and the shrimp head is naturally very clean.

Therefore, if you can ensure that the shrimp is a regularly farmed shrimp, the shrimp head can be eaten with confidence. In fact, in my country's cuisine, there are many delicacies that use shrimp head as raw materials, such as shrimp head paste.

But if you get shrimp from unreliable sources, such as crayfish in stinky gutters, or you can't determine the quality of shrimp at all, it's best not to eat shrimp heads for the sake of insurance.

No, frozen shrimp will turn black after a long time. Most people think that this is because the frozen shrimp have gone bad and should be inedible. In fact, this is only a one-sided view.

So, can you still eat frozen shrimp when it's black? Can you still eat black frozen shrimp? Is frozen shrimp black and edible?

The shrimp has been frozen for a long time, and the color of the head has become darker than before. Even black, but the flesh of the shrimp is still blue-gray, which is normal; Some shrimp heads are black, and the flesh of the shrimp body is red, but the meat is still elastic and edible. If the shrimp meat is "black and yellow" and has no elasticity, it must not be eaten!

Reasons why frozen shrimp turn blackIn addition to stale shrimp, there are three reasons why shrimp heads will turn black. After the shrimp die, the internal organs of the shrimp are easily damaged during the process of handling and squeezing, so much so that after the shrimp is cooked, even before it is put in the pot, the head and body of the shrimp turn black. In addition, I was fed too much feed when I caught shrimp, and it was put on the market on the same day.

The feed is cooked before digestion, and the shrimp tend to turn black after cooking. Normally, the shrimp will be cooked in a pot on high heat for a minute or two. If cooked for more than three minutes, the guts of the shrimp will easily crumble and the shrimp will turn black.

Also, when people buy shrimp, they look alive, but the shrimp they buy are usually in shopping bags. At this time, the shrimp is in a state of lack of oxygen, and when they get home, they are put in the pot. Many shrimp have very low activity, and in this state, the shrimp head is prone to blackening.

How to choose frozen shrimp? 1.Look at the shape.

Fresh shrimp have a complete head and tail that are closely connected to the body. The shrimp body is quite hard and has a certain curvature. Fresh shrimp is not tightly connected with the head and body, shell and meat, and the head and tail are easy to fall off or separate, and cannot maintain the original curvature.

After refrigeration, the intestines and meat of the shrimp will not stick very tightly. We found that the intestines and flesh of the shrimp were loose, indicating that the shrimp was not dead but fresh. 2.

Look at the color of the fresh shrimp skin, the shell is shiny, the river shrimp is blue-green, and the shrimp is blue-white female shrimp or egg yellow male shrimp. The skin of stale shrimp turns black, and the primary color of shrimp turns red or grayish-purple. 3.

Looking at the fleshy shrimp, the meat is firm and tender, and it is hard and elastic to the touch. Fresh shrimp, soft meat, poor elasticity. 4.

Smell the smell of fresh shrimp smells normal, there is no peculiar smell. If there is a foul smell, it is spoiled shrimp. 5.

Touch the shell Fresh shrimp shell must be hard, green, bright, prominent eyes, firm flesh, and strong fishy smell. If the shell is soft, gray in color, the eyes are sunken, and the shell flesh is slightly separated, it means that the shrimp has just died.

Fresh shrimp are frozen in water and not frozen in water, and the shrimp head will turn black after being put in the refrigerator for a long time, but the time for the frozen shrimp to turn black after putting it in the water will be a little slower. From the shrimp head to the outer skin of the shrimp body, the first black is the shrimp head and shrimp feet, when you see the shrimp head begins to blacken, it means that the shrimp should be eaten, the shrimp body has turned black, the meat inside has begun to loosen, and if you don't eat it, it will be bad. Seeing shrimp with black hair is not a sign of rot and is completely edible.

Seafood is best eaten fresh, and shrimp that has been left for a long time does not taste as good as not frozen.

Shrimp will turn black when frozen for a long time. It is normal for shrimp in the refrigerator to turn black. Shrimp itself is a high-protein food that contains PPO (polyphenol oxidase), especially on the head and thorax, which catalyzes a series of biochemical reactions.

Under aerobic conditions, PPO oxidizes the colorless compound monophenol on the surface of shrimp to colorless bisphenol, which converts bisphenol into colored quinone. Quinones easily combine with amino acids in shrimp to form dark brown complexes and turn black.

Let's take a look at how to properly freeze and preserve the prawns so that they don't turn black:

If you want to preserve the prawns, the first thing you need to do is to set aside a lot of empty bottles! Take Lao Yu here as an example, because the shrimp is about to be marketed in large quantities, our family now keeps the finished mineral water bottles, which is the most important prop for preserving the shrimp!

Once the bottle is ready, it's time to buy shrimp! When buying shrimp, pay attention to the fact that in addition to picking out dead shrimp, remember not to catch or pick with your hands, otherwise even if the shrimp is fresh at that time, there will be blackheads when you go home! Shrimp can survive for a long time after leaving the water, so just stick your mouth a little bit and don't let it pop out!

The shrimp look like they were bought home and they were almost as fresh as they were before they were bought! Because I'm in a hurry, I look stationary, but it's actually all fresh shrimp jumping around!

That's when the bottle comes in! Rinse your hands off the faucet to cool down, then quickly fill the bottles one by one with the shrimp head down! Every bottle of shrimp is filled and quickly placed in the freezer compartment of the refrigerator to freeze. Then, repeat the step!

Note: Shrimp must not be washed, after washing, it will be blackhead or spoiled. When loading shrimp, it is best to rinse your hands after filling a bottle of shrimp to cool down and try not to affect the quality of shrimp!

After freezing the shrimp for a day and night, take it out again, unscrew the cap and pour cold water into it, and put it back in the refrigerator to freeze again. Such frozen shrimp, within a year, no matter when it is taken out, the quality of the shrimp is almost the same as when I first bought it, not only the meat is tender and not powdery, the Q bomb is delicious, and the shrimp head is not black or off.

If the shrimp is put in the refrigerator for a long time, there will be a change in color, sometimes it will turn black, but this is normal, as long as the shrimp meat does not turn black or yellow, there is no problem, observe the shrimp meat when you do it, if it changes color, don't eat it!

How to preserve fresh shrimp:

Suggestion: Fresh shrimp can be placed in a cola bottle, and after it is full, fill it with light salted water, tighten the cap, and you're good to go. Methods like this can be saved, at least for four or five months, no problem!

You can eat it,After taking it out of the freezer, it is put into the refrigerator to oxidize the polyphenol oxidase, so that the shrimp turns black and does not affect the eating. When serving, remove the shrimp head and tail.

The appearance of the live shrimp is clean, and it feels dry when touched by hand. However, when the shrimp body is about to deteriorate, the granular cells that secrete mucus under the carapace disintegrate, and a large amount of mucus seeps into the body surface, making it slippery to the touch. If the shell sticks to the hand, it means that the shrimp have gone bad.

Fresh shrimp are bright in color. Depending on the species of shrimp, there is a slight difference in color. Fresh prawns, Roche shrimp and grass shrimp are blue, sea-caught prawns are pink, and bamboo shrimp and Jiwei shrimp have black and white patterns with a slight pink.

If the shrimp has black hair, it is not a fresh shrimp, and the whole shrimp is relatively black and not bright, which means that it has deteriorated.

Frozen shrimp can still be eaten even after it turns black. The blackening of shrimp is mainly due to the action of enzymes and has little to do with microorganisms. Even under freezing or refrigeration conditions, tyrosinase remains active, so melanism still occurs.

The head of the shrimp is also the internal organs of the shrimp, and if the shrimp happens to eat a lot of dark algae, such as brown algae, before fishing, the shrimp may also have a black color.

In addition, there is a risk that the undigested feed of farmed shrimp may be black. Therefore, a blackened shrimp head does not necessarily mean that the shrimp is not fresh. From this point of view, the blackening of the shrimp head is not such a terrible thing, and it needs to be treated correctly.

It is edible, and the shrimp head and shell can be removed and continued to eat.

The main reason why shrimp turns black is that the polyphenol oxidase in the shrimp body makes tyrosine produce melanin, and the polyphenol oxidase in the shrimp head is more, so this situation occurs. After taking it out of the freezer, it is put into the refrigerator to oxidize the polyphenol oxidase, so that the shrimp turns black and does not affect the eating.

Yes, the shrimp has been frozen for a long time, and the color has become darker or even black than the beginning, but the flesh of the shrimp body is still blue-gray, which is normal. Some shrimp heads are black, and the flesh of the shrimp body is red, but the meat is still elastic and can still be eaten.

If the shrimp meat is "black and yellow" and has no elasticity, it must not be eaten.

There is no absolute answer to this, it depends on the situation. Not all blackened shrimp can't be eaten, and if they turn black before they are taken out of the freezer, they are not fresh and it is best not to eat them. If it is fine before thawing, and it changes color and black after thawing, it is generally a relatively normal situation and can be eaten.

The main reason why shrimp turns black is that the polyphenol oxidase in the shrimp body makes tyrosine produce melanin, and the polyphenol oxidase in the shrimp head is more, so there will be a situation that the shrimp is black, and after taking it out of the freezer, it is put into the refrigerator to thaw, and the polyphenol oxidase is oxidized, so it turns black.

It is generally normal for shrimp to be freshly thawed and blackened. However, if it is not eaten in time after thawing and left for two days, the shrimp is likely to have spoiled. Two days is already a long time, and the weather is hot in summer, smell if it stinks after blackening, if it stinks, it means that it has deteriorated, so don't eat it anymore.

Seafood should be eaten fresh, and it is not good for the body to eat it after leaving it like this for a long time.

It's true that this kind of shrimp is not particularly fresh, but it generally doesn't matter if you eat it, but the taste is not as good as the original, and it is not delicious enough. Or for the sake of food aesthetics, it is recommended to remove the shrimp head and shell and continue to eat.

Generally speaking, it can be eaten but the taste will deteriorate, it is not so fresh, the meat is no longer so firm, and even has the feeling of falling slag, which is caused by improper storage, and it must be cooked if you eat it.

The main reason why the shrimp turns black is that the polyphenol oxidase in the shrimp body makes tyrosine produce melanin, and the polyphenol oxidase in the shrimp head is more, so there will be such a situation, after taking it out of the freezer, put it in the refrigerator, and let the polyphenol oxidase oxidize, so it leads to this situation.

Such shrimp are not particularly fresh, but it does not matter if they are eaten, and the shrimp head and shell can be removed and continued to eat.

I think if the frozen shrimp turns black, it shouldn't be eaten, he must have had a quality problem.

1. If it is black before it is taken out of the freezer, it is not fresh. It is better not to have to finish it.

2. If it is fine before the unfreeze, it will fade and turn black after the unfreeze, which is generally a more normal condition. The key to the blackening of shrimp is that the polyphenol oxidase of the shrimp body causes tryptophan to cause pigment, and the polyphenol oxidase of the shrimp head is large, so the shrimp will be black.

Can you still eat frozen shrimp when it turns black.

It is true that the shrimp is not very fresh, but it generally does not matter if you take it, but the taste is not as good as the original, and it is not delicious enough. Or for the sake of the beauty of the ingredients, it is recommended to remove the shrimp brain and shrimp head and take it again.

3. It is generally normal for the shrimp to be unfrozen and turn black soon. However, if you do not take it immediately after unfreezing and leave it for two days, the shrimp is likely to be moldy. Two days is already long, and the temperature is hot in summer, after it turns dark, smell whether it smells bad, if it smells, it means that it has already been moldy, so don't take it.

Seafood products should be eaten fresh, and it is not good for the health to eat after leaving it like that for a long time.

4. Naturally, in addition, you also have to discern it. Since frozen shrimp also have a shelf life. Seeing that the shrimp has black hair, but the flesh of the shrimp body is still gray-green, this belongs to everything normal; Some shrimp have black brains and red flesh, but the meat is also malleable and still edible.

If the shrimp "turns black and yellow" and has no malleability, it must not be eaten. Therefore, it is necessary to look not only at the color tone, but also at whether there is any smell, and whether the texture of the meat of the shrimp body is malleable.