Why does seafood smell

But unless you live right on the coast, have an exceptional fishmonger, or caught the fish yourself, most likely the fish you buy at the supermarket will be a few days old and will start to begin smelling quite strongly.

Image Credit: eatinbrixton. So what exactly makes up the familiar smell of fish? Sometimes they do, and other times they smell of things that we might think of as pleasant, such as caramel and peaches. The main component, however, in that distinct fishy smell is a molecule called trimethylamine oxide TMAO , which is contained in the tissues of most sea creatures. The eyes should be clear and bulge a little. It should have firm, shiny flesh and spring back when pressed. It should not display darkening or drying at the edges.

Getting your hands on fresh fish is more than a luxury. Join the New Times community and help support independent local journalism in Miami. Get the latest updates in news, food, music and culture, and receive special offers direct to your inbox. Support Us Miami's independent source of local news and culture. According to Don Glass from A Moment of Science , "fish tissue contains an odorless chemical known as triethylamine oxide. Once the fish is killed and exposed to air, the chemical breaks down into derivatives of ammonia, and therefore smells bad.

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With local media under siege, it's more important than ever for us to rally support behind funding our local journalism. Treating the fish with acidic ingredients such as lemon, vinegar, or tomato can also cause TMA to bind to water and become less volatile. Thus, the odor compounds do not reach the nose.

Freshwater fish generally do not accumulate TMAO because their environment is less salty than their cells. As a result their flesh tends to be milder, and they do not get as "fishy" as ocean fish. However, freshwater fish sometimes suffer from an unpleasant "muddy" aroma. This often occurs in bottom-feeders such as catfish, and is caused by two compounds produced by blue-green algae, geosmin and methylisoborneol. These chemicals concentrate in the skin and dark muscle tissue of the fish.

Acidic conditions will cause these compounds to break down, so there is good reason for the inclusion of acidic ingredients in traditional recipes.

Both do not acquire their powerful odors until humans have intervened and prepared them for consumption.