Animal-based foods generally contain fishy substances, with the odor of aquatic products being particularly prominent. It intensifies as the freshness of the food decreases. These off-flavor substances not only cause nausea but also pose health hazards after consumption. There are many methods to remove the fishy taste during cooking. Depending on the degree of off-flavor in the ingredients, a combination of measures can be taken to achieve the goal of deodorization.
Neutralization to remove fishiness:
Animal-based food ingredients are rich in nutrients such as proteins, amino acids, and lecithin. Due to the action of environmental and inherent bacteria, various fishy substances are produced, including ammonia, trimethylamine, methanethiol, hydrogen sulfide, indole, and heterocyclic nitrogen-containing compounds. The aforementioned fishy and odorous substances are all alkaline compounds (pH greater than 7.25). By adding an appropriate amount of vinegar during cooking to neutralize them, forming acetates, the fishy odor can be significantly reduced. Furthermore, tomato sauce contains organic acids like citric acid and malic acid, which also have a neutralizing and deodorizing effect. Of course, cooking fish and meat directly with tomatoes also yields a deodorizing result.
Alcohol to remove fishiness:
For some fishy substances with low boiling points and non-alkaline properties that cannot be removed by neutralization, the dissolving and volatile properties of alcohol (ethanol) can be utilized. Alcohol first dissolves aldehydes, ketones, and sulfur-containing compounds in fish and meat, which are then volatilized and removed upon heating, eliminating the fishy odor. Meanwhile, ethanol can also react with aldehydes in the ingredients to form aromatic substances—acetals. It can also combine with organic acids to form esters. The combined effect of these two reactions can deodorize the dish and enhance its aroma. Therefore, to achieve a fresh and savory flavor in fish and meat, cooking wine and vinegar are indispensable.
Spices to remove fishiness:
China boasts a wide variety of spices, which can be selected according to the specific situation. For example, onions contain volatile oils and onion-garlic pungent substances; ginger contains gingerol, gingerene, and shogaol; Sichuan pepper and black pepper contain sanshools; star anise contains anethole and anisole; and cinnamon bark contains volatile oils and organic acids. The substances mentioned above can cause aldehydes, ketones, and other fishy components to undergo oxidation, acetalization, or esterification reactions, which weakens the off-flavor and enhances the aroma. This effect is particularly pronounced when used in animal-based ingredients with a strong gamy or fishy odor.
Heating to remove fishiness:
Fishy substances with low boiling points, such as methanethiol and ethanethiol, can be removed by heating. Some fishy substances with higher boiling points can also be removed by prolonged heating methods such as stewing, braising, roasting, or grilling, or by allowing them to volatilize in hot oil. Most fishy substances are water-soluble. During cooking, methods like blanching or scalding in boiling water can be used first to remove water-soluble fishy substances like urea, amines, and low-molecular-weight acids before proceeding with the main cooking process.