1, shrimp head black can eat
Raw shrimp blackened mainly due to the role of tyrosinase in its body, tyrosinase is also the human body to promote the synthesis of melanin substances in shrimp, crab blood contains such substances. Tyrosine in the shrimp meat after the role of the enzyme, producing black substances such as brown pigment, which in turn led to the blackening of the shrimp head. In fact, other seafood has a similar situation, just sea shrimp white color, easier to find.
In fact, in addition to the shrimp head, raw shrimp for a long time, other parts will be black. Raw shrimp refrigeration can not completely inhibit the activity of tyrosinase, so it will also be black.
In addition, shrimp eaten food such as seaweed, shrimp head part of the viscera rupture, as well as a long time preservation, etc., will lead to blackened shrimp head, which has nothing to do with whether heavy metal pollution. Whether there is water pollution, heavy metal pollution is not visible.
2, cooked shrimp blackened causes
One, the shrimp is not fresh, shrimp out of the water after the viscera rupture, rapid oxidation and blackening, the longer the placement time, the blacker the more serious. Second, the shrimp eat the feed caused by the general culture of shrimp have this characteristic. Third, the cooking time is too long, resulting in viscera rupture and blackening.
Shrimp head blackened whether you can eat, according to the freshness!
The degree of blackening of raw shrimp, although to a certain extent can reflect the degree of freshness, but it is its own enzyme action, and microbial action is different. Can be judged by smelling, looking and touching.
Smell the smell of shrimp, aquatic proteins with high water content, very easy to corruption produce a stimulating odor; see whether the head of shrimp off, shells and meat separation and shrimp shells are red, raw shrimp shrimp shells red, is not fresh performance; touch the shrimp meat is elastic, flaccid for the performance of the not fresh.
In addition, go to the restaurant to eat shrimp, braised, dry pot, deep-fried and other practices will use the shrimp meat is not fresh, and is not easy to be found. On the contrary, steamed shrimp, boiled shrimp if not fresh is very easy to be found.
3, how to prevent the shrimp head black
Refrigeration can not prevent the shrimp head black, but the enzyme in the shrimp head needs oxygen to participate in the action, so the vacuum port and then refrigerated to stop the raw shrimp black. Another method is to let the enzyme inactivation, usually use the heating method, that is, cook the shrimp, boiling water under the pot to cook, if not cooked through after a period of time will also turn black. However, it is not recommended that you eat shrimp that have been stored for a long time.
4, shrimp nutritional value
Shrimp nutritional value is very high, can enhance the body's immunity and sexual function, tonifying the kidney and Yang, anti-premature aging. Eat fresh shrimp (fried, burned, stewed can be), warm wine to serve, can cure kidney impotence, cold, body tired, waist and knee pain and other diseases. If a woman has little or no milk after delivery, 500 grams of fresh shrimp, crushed, yellow wine hot service, 3 times a day, even served for a few days, can play the role of lactation. Shrimp skin has a sedative effect, often used to treat neurasthenia, vegetative nerve disorders. Sea shrimp is a delicious food that can provide nutrition for the brain. Shrimp contains three important fatty acids, can make people stay concentrated for a long time.
5, shrimp efficacy and role
Shrimp tonic effect and medicinal value are high. The motherland medicine, shrimp taste sweet, salty, warm, have yang yi kidney, tonic, through the function of milk. Anyone who has been sick for a long time, weakness, shortness of breath, diet, yellow and thin people, it can be used as nourishing and healing food. Regular people eat shrimp, but also fitness powerful effect. Specific use is: the treatment of impotence, can be 150 grams of fresh shrimp, leeks 250 grams, add oil and salt together with fried food, or fresh prawns with glutinous rice, sweet wine stewed, daily morning and evening in moderation; treatment of impotence, lumbago, fatigue, can be used for shrimp 50 grams of Cordyceps 15 grams of Cordyceps Sinensis 15 grams of nine incense worms 15 grams of water, water decoction, day 1 agent; treatment of spleen and kidney deficiency of the symptoms, available shrimp 15 to 20 grams, washed, 500 grams of bean curd, cut blocks. The two flavors are then put together in a pot. Then put the two flavors together in a pot of water, and add green onions, ginger, salt seasoning, to be cooked shrimp, eat tofu, shrimp, drink soup.
6, lobster buying tips
1, the season: crayfish is the best time to eat is from May to October, yellow full of meat fat, even the three sections of the large chelae on the head stuffed to the end of the elastic teeth of the snowy muscle;
2, color: look at the crayfish is clear water is muddy water, a look at the back, red and clean, which is still available, and then turn over to look at it! Abdominal fluff and claws on the hairs, here if it is white and neat, basically clean water raised;
3, size: we try to buy just grown lobster, too small, after all, food tasteless, touch its shell with your hand, hard iron hard iron is the old undoubtedly, like fingernails with elasticity is just grown up before shelling, so we have to buy soft shells.