The fighting power of fishy smell is comparable to that of a nuclear bomb, but some people prefer this taste...

How can anyone like to eat fishy-smelling food!

And most of them will become delicious food in their mouths.

Fish smells fishy, ​​blood smells bloody, and even soil smells earthy. Why do some people like fishy smells? Where does the fishy smell come from?

Fish, meat, and other fishy smells in food

Kitchen experts should all know that part of the food processing process involves a step called removing fishy smell.

Fish has a fishy smell, eggs have an eggy smell, mutton has a fishy smell...the sources of the fishy smell of different foods are also different.

You are all common ingredients, why do you taste so "fishy"?

Image source: Wikipedia

First, let’s talk about the fishy smell of fish and seafood.

The source of the fishy smell of marine life and freshwater life is different. The fishy smell of marine life comes from seawater, which contains 35g of salt per kg of seawater.

A large amount of salt will have an osmotic effect on the cell membrane of marine organisms, causing the water in the cells to continue to drain. In order to prevent themselves from becoming overly dehydrated and turning into dried fish and shrimp, marine organisms have evolved a "special function", which is to increase the concentration of cell fluid and fill the cell gaps with amino acids and ammonia-containing compounds.

This can keep the osmotic pressure inside and outside the cell in a balanced state, and allow the body to survive.

Because glycine, glutamic acid and trimethylamine oxide in amino acids have a savory taste, fish, shellfish, shrimp and other marine life have a savory taste. However, these substances are a double-edged sword, and they are also the culprits of the fishy smell in seafood. Among them, the leading creator of the fishy smell is trimethylamine oxide.

You should know that when seafood lives in the sea, trimethylamine oxide does not emit any odor. But when they are caught and suffocate to death, trimethylamine oxide will gradually degrade under the action of enzymes and anaerobic microorganisms to produce trimethylamine, dimethylamine and other aliphatic amines... and these substances themselves have a fishy smell.

What is even more unacceptable is that although the concentration of trimethylamine in dead seafood is very low, it has a foul fishy smell. High concentrations of trimethylamine will emit an unbearable rotten egg smell. This substance is mixed with hexahydropyridine, δ-aminovaleric acid, δ-aminovaleraldehyde, etc. in the fish skin, making the fish "more fishy" (especially serious for marine fish).

Another thing that many friends who love to eat and cook fish are frustrated about is that trimethylamine is a substance that cannot be dissolved in water... So every time we finish handling fish, we always feel that the fishy smell on our hands will not disappear no matter how we wash...

The reason why meat produces fishy smell is more complicated. Because pork, beef and mutton generally contain large amounts of nutrients such as protein and amino acids, coupled with the breeding environment and the bacteria they carry, they will produce "fishy smells" such as ammonia, trimethylamine, hydrogen sulfide, indole, and methyl mercaptan.

However, unlike marine life, we can remove the "fishy smell" on our hands after handling meat.

Earthy smell

There is another smell that some people like very much, that is the fragrance of soil after rain - the smell of earth. The smell of earth is actually caused by the body odor produced by actinomycetes - geosmin.

Image source: Wikipedia

Geosmin itself is a very volatile substance. Scientists initially attributed the fragrance of soil to organic matter in the air or to biological components that died in the soil.

It was not until 1881 that scientists discovered that this "earthy smell" could be separated and extracted from the soil, so this unique smell was also used to make perfume... Tadpole Jun thinks that this taste is also unique enough...

Smell of blood

The smell of blood often makes people feel uncomfortable, but for "meat lovers" at the top of the food chain in the animal kingdom, the smell of blood is a fatal attraction.

Animal behavior researchers at Linköping University in Sweden have found that mammals' blood contains key molecules that can emit "blood qi." In other words, even a glass of plain water with this kind of substance added can make carnivores go crazy.

Image source: Wikipedia

Researchers say that for predators, the smell of animals is a crucial attraction, and the main source of the smell is blood.

So what substance gives blood such a unique smell? After a series of studies, the researchers finally locked on a substance called trans-4,5-epoxy-2-decenal.

This complex molecular substance belongs to the aldehyde compound, which emits a metallic smell, which makes people associate it with the fishy smell of blood. Our blood also emits a rust-like smell, which is mainly the smell of the ferrous ions contained in human hemoglobin after being oxidized.

"Fishy smell" is actually a magical smell. It is not one of the five flavors, but it exists in our daily lives. Some people love it, while others hate it. Do you like "fishy smell"?

Review expert: Sun Yafei, Ph.D. in Chemistry from Tsinghua University.

Source: Tadpole Musical Notation

Editor: Xiaoxi Tushuo