Final answer:
Soaking seafood in acid causes neutralization of volatile amines, which reduces odor and adds flavor. It also denatures the proteins in the seafood, causing them to coagulate or 'cook' similar to the 'salting-out' effect observed with the use of salt in marinating.
Step-by-step explanation:
Soaking seafood in acid, such as lemon juice or vinegar, which contain citric and acetic acid respectively, affects the proteins in seafood. The acid initiates a neutralization reaction with volatile amines present in the fish, resulting in the formation of involatile ammonium salts. This reaction not only diminishes the fishy odor by neutralizing the basic substances but also imparts a pleasing sour taste.
Furthermore, the acid exposure causes the proteins in the seafood to denature, altering their structure without breaking peptide bonds. This denaturing process makes the proteins coagulate or 'cook' without the application of heat. The phenomenon shares similarities with the marinating process where salt leads to a reduction in protein-water interaction and increases protein-protein interactions, resulting in the 'salting-out' effect where the proteins precipitate or solidify.