Why does fish smell fishy?

Fish usually have a unique smell called "fishy smell", which is related to the biochemical components in the fish body and subsequent chemical reactions.

Trimethylamine odor: The main source of fish odor is a substance called Trimethylamine. Trimethylamine is produced by the breakdown of amino acids in food in fish, specifically during the microbial degradation of fish proteins. This substance is usually harmless in fish, but can be found in higher concentrations in some fish such as cod and eels.

Microbial degradation and oxidation reactions: When fish are left untreated for too long after being caught, or the storage conditions are not good, microbial degradation and oxidation reactions in the fish will promote the formation of trimethylamine, exacerbating the fishy smell. In addition, the involvement of food contact surface oxidation, oxidases, and bacteria may also lead to the oxidation of amino acids and the production of fishy compounds.

Type and environmental factors: Different fish may cause different degrees of fishy odor due to their unique physiological constitution and feeding habits. At the same time, environmental factors such as the feeding environment, feed, and water quality may also affect the production of compounds in fish, indirectly affecting the presence of fishy smell.

Fish freshness: Fresh fish tends to have a less fishy smell. After fish spoils, both oxidation reactions and microbial degradation will accelerate the formation of trimethylamine.

In order to reduce the fishy smell, people usually deal with it in the following ways:

• Quickly freeze caught fish to slow microbial degradation

• When cleaning the fish, remove the intestinal tissue and gills. These parts usually contain higher concentrations of Trimethylamine.

• Use salt, vinegar, lemon juice, onions, etc. to cook or pickle at low temperature to reduce the fishy smell

Even if fish has a fishy smell, neutralizing seasonings and cooking methods can reduce or even mask the taste and add flavor.

animal tags： fish