Foodie says: The ones that run on the ground are not as good as those that fly in the sky, and the ones that fly in the sky are not as good as those that swim in the water...
The main thing that swims in the water is fish. Compared with the pig, beef and mutton that everyone often eats, eating more fish is more beneficial to health.
my country's " Dietary Guidelines for Chinese Residents " also recommends that you can eat fish twice a week or 300 to 500 grams of fish meat per week, and the average is recommended to 40 to 75 grams per day.
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However, according to the data in the "Scientific Research Report on Dietary Guidelines for Chinese Residents 2021", only 25.6% of Chinese residents' daily average fish and shrimp intake reached the standard and above in 2018, and 74.4% of adults' daily fish and shrimp intake was less than 40 grams per day. In terms of livestock and poultry intake, the daily livestock and poultry meat intake of ≥ 75 grams among people aged 18 to 44 years old is a high proportion, all of which are more than 58%.
Therefore, most of us have to pay attention to it. We can increase the intake of fish and shrimp in our diet, and reduce the intake of some livestock and poultry meat.
Regarding why you recommend eating fish and how to make delicious food, I will talk about this article in detail, and finally teach you how to buy fish.
01
What are the benefits of eating fish?
Most fish meat is light white, which is related to the fish's growth environment. The fish live in the water and swim every day, so it takes a long time of endurance to complete it. Water will also produce buoyancy and resistance to fish. The faster you swim, the greater the resistance. Therefore, fish also need to have enough power to accelerate, so fast white muscle fibers that need to store emergency energy occupy most of the muscle mass, mainly to facilitate sudden acceleration. Some fish have more red meat on them. These fish are generally fish that can swim for a long time in one breath, and have more pink muscle fibers on them.
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Most land organisms rely on oil to store physical strength, while fish rely on protein in their muscles to store physical strength. Therefore, fish contains more protein, generally content is 15%~22%, and it is also high-quality protein, with a high absorption and utilization rate.
At the same time, because fish live in water all year round, they need their body to maintain normal operation even at 0 ℃, so their fat structure is very long and irregular, and they contain a lot of unsaturated fatty acids, mainly n-3 series. Especially the fish living in seawater are more abundant. This fatty acid plays an important role in human health, and it is related to the health of the brain and retina, the health of the cardiovascular and immune system.
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A diet rich in n-3 series polyunsaturated fatty acids has anti-inflammatory effects, which can reduce blood cholesterol levels, inhibit the formation of thrombosis, reduce the risk of heart disease and cancer.
Studies have shown that eating more fish can reduce the risk of all-cause death, stroke , and can also reduce the risk of Alzheimer's disease and cognitive dysfunction.
In addition, the vitamin A and vitamin D in the liver of fish are also rich in content, which can promote the body's absorption and utilization of calcium, and is also beneficial to the health of the eyes, and can prevent night blindness.
02
When is the best fish?
The livestock and poultry meat that people often eat usually takes several hours to reach the maturity stage after slaughtering, and the maturity stage is the most delicious. Fish are different. Fish mature very quickly after slaughtering, and it is more delicious after being left for a short period of time. Some fish will taste more delicious when they just passed the stagnation period, about 8 to 24 hours after death, but if they pass the stagnation period, the fish will easily rot and deteriorate. This is why many restaurants have "live fish" now.
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03
What happens after fish is heated when it is cooked?
When fish is heated when heated, the texture, smell and color will change. These changes make cooked fish look more appetizing than fresh fish.
① Changes in the color of fish meat:
Fish and shellfish foods are both transparent when fresh. After heating, due to myoglobin degeneration, it will change from transparent to white.
, but for shrimp and crab , it is different. Shrimp and crabs generally have a cyan appearance in fresh state. This is because flaxtin and protein combine to form pigment protein. After heating, the protein becomes denatured. flaxtin is oxidized to flaxtin , so it will turn into a red appearance.
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② Changes in the texture of fish meat:
As the temperature gradually increases during the cooking process, the texture of fish meat is gradually changing in addition to the color changes. After the temperature is above 60 ℃, the muscle tissue will contract, the moisture content will continue to decrease, and the hardness will increase.
The meat of fish is relatively fragile and will break if you are not careful. This is because fish muscles are layered, layer by layer to form a "W" shape, and the connective tissue is low in content, so they cannot maintain the shape better. During the heating process, at 50 ~ 55 ℃, collagen in the connective tissue of the fish will begin to decompose, causing the muscles of the fish to start to layer and become section by section.
Therefore, cook fish with low heat and should not be too long. If heated for a long time, it will not only cause the fish to be old and hard, but it will also easily break the fish. A piece of fish that is 2.5 cm thick will cook in about 10 minutes. If the meat is thick, you can cut it diagonally every 1 to 2 cm to improve the problem of uneven thickness of the fish that affects cooked thoroughly.
Someone has done a cooking experiment on bream . 500 grams of bream can be fully cooked in a steamer at 100 ℃ for 8 minutes, and the texture is just right. If you are marinated with appropriate amount of salt, under the same heating conditions, steam it for about 9 minutes and the meat will be completely cooked and tender.
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When cooking fish, you can first slice the fish into medium-sized fish steaks. Put the fish steaks in the pot before the heated soup is about to roll, then turn off the heat, add a little cooled cooking juice to reduce the temperature in the pot to 65 ~ 70 ℃ (a thermometer is available), cover the lid and let the fish steaks cook slowly.
③ Changes in fish smell:
Most people’s impression of fish smell is “fishy”. In fact, extremely fresh fish meat does not smell mainly fishy, but like the taste of plant leaves after juicing. Almost all fish carries a aromatic molecule that exudes a strong geranium leaf scent, and a little metallic scent, freshwater fish carries the scent of "freshly cut grass" and earthy.
The earthy flavor mainly comes from earthy odorants, concentrated in fish skin and dark muscle tissue. Generally, vinegar or other sour flavored seasonings can be used to decompose it.
The fishy smell mainly comes from trimethylamine . This is because the trimethylamine oxide produced by fish in order to balance the salt concentration of seawater encounters bacteria on the fish's body, so it is decomposed into fishy trimethylamine.
If you want to remove the fishy smell, you can first rinse with clean water to rinse off the trimethylamine on the surface of the fish body. Then marinate with acidic seasonings such as vinegar and lemon. They can provide hydrogen atoms to combine trimethylamine to bind to water and other molecules, so that the fishy smell will not spread into the nasal cavity when we eat fish.
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Fresh fish has a unique flavor, but the heated fish will have a unique flavor due to the interaction between fatty acids, oxygen molecules, amino acid and other substances. Fresh fish contain more nucleotide , which will show an umami flavor after being heated. The content of volatile acids, nitrogen-containing compounds and carbonyl compounds in cooked fish is significantly increased, which are all volatile ingredients, so it will make us smell an attractive aroma.
The fish processed by barbecue, frying, smoke and other methods will have a better flavor. If the sauce is also applied while grilling fish in , then the ethanol, soy sauce, sugar and other substances from the sauce will also participate in the heating reaction. In addition, the various amino acids and oligo peptides produced by the hydrolysis of fish proteins will make the overall smell better, coordinated, prominent, and taste better, delicious and rich.
04
Which fish are recommended to eat?
Although it is recommended that everyone eat fish frequently, not all fish can be eaten.Especially seawater fish, there may be problems with heavy metal pollution. The amount of pollutants in fish meat is related to their eating habits and living waters. Large predatory fishes at the top of marine food chain have a higher toxin content.
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Every chemical substances manufactured worldwide will eventually accumulate in marine organisms . Among them, the most harmful ones are dioxins and polychlorinated biphenyls , which will harm our nerves and brain. Organic pollutants can also cause liver damage, cancer and endocrine disorders.
On January 18, 2017, the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) released the final version of fish consumption recommendations, recommending eating 227 ~ 340 g of low-mercury fish every week. Do not choose fish with high mercury content, such as big-eared mackerel, big-meat tuna , marlin , swordfish , New Zealand red fish , etc. As for the specific recommended fish, you can see the picture below:
Image source: US FDA Fish Eating Recommendations
In addition, women, pregnant women and young children should avoid eating larger or hunting fish, such as tuna (especially tuna and bluefin tuna ), jinshi , shark, swordfish, sabre , tangerine sabre , tangerine sabre , tangerine sabre sabre and king mackerel, etc., because the heavy metal methylmercury content may be higher than other fish.
05
How to choose a good fish?
If you want to eat delicious, nutritious and safe fish, you need to pay more attention when purchasing fish. It is recommended to refer to the following 4 points to buy:
①Look at Fish scales : The fish scales look fresh and shiny, close to the fish body and are not easy to fall off, just like armor, this is a fresh fish; for non-fresh fish, the scales lose their luster, the scales are loose and easy to fall off, and are not tight.
②Look at fish gills: The gills of fresh fish are clean and bright red in color, without mucus or odor, and the gills of fish are tightly closed; while the gills of non-fresh fish are dark red, gray-red, or even green or white, with an increase in mucus and a fishy smell. The gills of fresh fish are loosened and the mouth is wide open.
③Look at the eyes: The eyes of fresh fish are clear and protruding, with black and white distinctions; while the eyes of non-fresh fish are collapsed, their eyes are turbid and there is a white membrane.
④ Press the fish body: The fresh fish pressed with the hand without depression, elasticity, and hard feel. After pressing the soft part of the meat, it can recover immediately, and the fish belly will not expand; while the fish body pressed with the hand with the hand with the fish body, soft feel, sticky, and cannot recover after pressing the soft part. Moreover, due to the effect of bacterial reproduction, the fish belly will swell and the belly door will protrude.
In addition, if you choose a live fish, the most active and responsive one is the best. Those who move slowly or float on the water may be the fish that is about to die.
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Adjust increase fish intake is beneficial to health, but it is recommended not to eat freshwater sashimi, and to eat less grilled and fried fish. Because freshwater fish may have parasite and bacterial contamination problems when making sashimi , while grilled fish and fried fish may produce carcinogens.
References: [1] Chinese Nutrition Society . Dietary Guidelines for Chinese Residents [M]. People's Health Publishing House .2022[2] Harold Maki [US]. Lin Huizhen Translation. Food and Cooking. Milk, Egg, Meat, Fish. Beijing Fine Arts Photography Press. 2013.8[3] Zhou Xiaoyan. Cooking Technology [M]. China Textile Publishing House, 2008.[4]http://www.fda.gov/food/consumers/advice-about-eating-fish[5]Hong Kong Special Administrative Region Government Food Safety Centre http://www.cfs.gov.hk/sc_chi/multimedia/multimedia_pub/multimedia_pub_fsb_201404.html
Author | Xue Qingxin Member of the Chinese Nutrition Society Registered Nutrition Technician Health Manager Public Nutritionist
Review | Chen Shengjun Nanhai Fisheries Research Institute of China Academy of Fisheries Sciences Associate Researcher
(Scientific Rumor Refute)
