How to easily distinguish fresh and healthy fish?

Generally speaking, the freshness of fish can be judged by the appearance and taste of fish eyes, gills and belly. But recently, some small shops will pack the fish first, which makes it more difficult to check. Some of them are even more difficult to distinguish when they are cut into pieces for sale, so whether the dividing line between the darker meat on the back of the fish and the ordinary meat is obvious becomes an indicator to distinguish whether the fish is fresh or not. The following is a reference for choosing fresh fish.

1. Choose fish with bright red gills.

There is blood containing protein in the gills, so once the fish leaves the water, the protein in the blood will become a nutrient source for microbial reproduction on the gills. When cooking fish and shellfish, we need to remove gills first, because gills contain a lot of microorganisms, which may cause food poisoning if eaten, and gills also contain a heavy fishy smell, and the crispy taste is not pleasing.

2. Choose fish with clear and transparent eyeballs

Once the fish leaves the water, the protein in the eyeball will be denatured, thus changing the refractive index of light. In addition, microorganisms attached to the eyes will start to multiply and decompose protein, so the eyes will be turbid. Many people have heard that tuna eyes contain a lot of DHA (docosahexaenoic acid), which can strengthen blood circulation and activate the brain, so they only buy it for cooking! I believe everyone can understand that fish's eyeballs do contain a lot of lipids.

3. Choose bright red fish.

The red fish is because there is an iron-containing protein called myoglobin in the fish. When red meat fish is cut into sashimi or fillets, the surface of red meat is exposed to oxygen, and iron will turn brown.

Methemoglobin. In other words, we can judge whether a fish is fresh according to its color change: when it is bright red, it is fresh, but gray is not.

4. Choose fish with no broken incision.

If the fish is fresh, the incision of its slice will not break, but it will be neatly pointed; If you slice for a while, the incision will be a little broken and the corners will be round.

5. Choose the fish whose abdomen swells properly.

Fish also have digestive organs in their bellies. When they eat the bait in the water, they will also bring the microorganisms in the water into the digestive organs. Once the fish leaves the water, the microorganisms that stay in the digestive organs will act, and the food in the digestive organs will be broken down into putrefaction. At the same time, protein and lipid, which constitute internal organs, are also influenced by enzymes existing in digestive organs, and are digested into putrefaction by themselves, so the shape of internal organs will collapse and the expansion of abdomen will disappear.

Comparison of Freshness of Sashimi

The tuna (upper left) bought that day and the tuna (upper right) kept in the refrigerator for about 2 days lost water and turned black seriously. /(bottom left) The red soft-shelled turtle bought on the same day and the red soft-shelled turtle put in the refrigerator for about 2 days (bottom right) lost water, and the meat quality gradually lost its elasticity.