Kitchen Ash
The method of removing fishy smell with kitchen ash is quite simple. Take dry kitchen ash, put it in a basin or pot, then put the catfish in, cover it evenly. Use the ash to scrape the fish's body, repeat several times to remove the slime. As for eels and loach, put them in a basin or pot with a high edge, cover with a basket, add kitchen ash, a little salt and cover the basket so that the eel can wiggle out all the slime.
This method is still used by housewives in rural areas when kitchen ash is available at home.
Bamboo, Banana, Custard Apple Leaves
This is a folk method to remove the fishy smell of catfish, eels, and loach.
Just lightly crumple the bamboo leaves, banana leaves, then rub them all over the fish, eel several times, then scrape off, the slime and mucus on the outside will flow away. The astringent in banana leaves helps to effectively remove the fishy smell.
As for na leaves, they are often used when preparing ducks and geese. Just a handful of leaves, lightly crushed and rubbed when preparing will help the dish no longer have a fishy smell.
Rice Washing Water
Fish with a fishy smell such as silver carp, catfish, carp or eel, loach after cleaning should be soaked in rice washing water, add a little salt for 15-20 minutes and then rinsed again to significantly reduce the fishy smell. For catfish, to clean it better, rinse it with hot water when scraping the slime or combine it with kitchen ash for more effective results.
White Wine and Ginger
This method has been used by many coastal fishing villages for hundreds of years to both effectively remove the fishy smell and make the fish sweeter and more fragrant.
According to modern science, the cause of fishy smell in fish is due to the presence of amino acids such as trimethylamine, dimethylamine which have weak alkaline properties. With newly caught fresh fish, the content of this amino acid is low, the longer it is left, the more fishy smell it has. To remove the alkalinity from amino acids that cause fishy smell, using a mixture of white wine and crushed fresh ginger is the most effective.
Green Tea Water
Many provinces in the Central region often use green tea water to prepare and cook fish, which not only effectively removes the fishy smell but also enhances the flavor of the dish.
According to many studies, the tannin in green tea helps to effectively remove the fishy smell of fish. The tannin is also found in many green bananas. Many dishes such as snakehead fish cooked with banana, loach fish cooked with banana are delicious without being fishy.
Sour Substances
Since ancient times, mothers have used sour-tasting ingredients (containing organic acids) to neutralize the alkalinity of the fishy smell (trimelylamine) such as lemon juice, home-grown vinegar, and fermented rice.
Not only used for preliminary processing, sour substances are also used when cooking Northern fish soup such as doc, queo, thanh tra, tai chua, chay or vinegar, me. Southern fish soup uses tamarind and pineapple. In addition to removing the fishy smell, sour substances also help enhance the flavor, enhance the dish, and stimulate the taste buds.
Spice Leaves
In addition to the popular folk methods above, housewives in each region also use additional spice leaves to remove the fishy smell and make the dish more delicious and flavorful.
In Ha Long, coastal people often use betel leaves or guava leaves, crushed and rubbed on seafood so that when boiled, there is no more fishy smell.
Nghe Tinh people often use turmeric leaves when braising fish to both remove the fishy smell and give it a very unique characteristic aroma. People in the West use grapefruit peel to braise snakehead fish, which is very delicious and a specialty that many people remember.