The main reason for the fishy smell of food is that the amino acids in it decompose after heating, releasing volatile amino acids and nitrogen-containing compounds. Therefore, the principle of removing fishy smell can be started from the following aspects:

1. Acidic seasoning neutralizes fishy smell: Adding acidic seasoning (such as lemon juice, vinegar and wine) can neutralize volatile compounds released by amino acids and weaken fishy smell.

2. Accumulation of fragrance: Soaking the ingredients in salt water, ginger juice, onion juice and other liquids can help the ingredients emit a specific smell and neutralize or cover up the fishy smell.

3. Cooking to remove fishy smell: High-temperature cooking methods such as steaming and boiling can volatilize volatile smells in ingredients and reduce fishy smell.

4. Deodorize with activated carbon: Activated carbon can adsorb odor molecules. Put the ingredients in an activated carbon box or put some activated carbon above the stove to remove the fishy smell of the ingredients.

5. Marinate the ingredients with salt, vinegar and sugar: The salt, vinegar and sugar in the seasoning can neutralize the fishy smell in the brine and remove the alkaline taste.

To sum up, the principle of deodorization is to neutralize, cover up, decompose or absorb the fishy smell in the ingredients by different methods, so as to make the ingredients more delicious.