Aquatic animal resources mainly include fish, shrimp, crabs and shellfish, among which the aquatic resources of crabs and shellfish living in the ocean are called seafood, which is a very important source of human diet and is mainly obtained by fishing; Freshwater aquaculture is also an important way for people to obtain aquatic food resources, especially in China, the largest freshwater aquaculture country in the world. Since the founding of New China, the artificial propagation of silver carp and bighead carp has been studied systematically and deeply, and a series of research results have been obtained, which fundamentally solved the supply problem of the four big fish fry and laid the foundation for the artificial propagation technology of aquatic animals. At present, China's freshwater aquaculture has been in a state of blooming, and there are many special aquaculture varieties in many places, such as tilapia in Guangdong, hairy crabs in Yangcheng Lake, giant salamander and bullfrog, which provide people with a wide variety of ingredients. We can choose according to our own preferences, so as to achieve the goal of balanced diet and diversified food.
Fish is rich in protein, which is easily digested and absorbed by human body. It is rich in inorganic salts such as calcium, potassium and selenium, as well as nutrients such as vitamin A, vitamin D and B vitamins. It is recognized as a healthy food, suitable for most people, especially children in the growth and development stage. Eating more fish food is more conducive to healthy growth. In fact, except the most familiar fish, other aquatic animals such as shrimps, crabs and shellfish are high-quality resources in protein, with complete nutrition, easy digestion and absorption and high bioavailability. According to modern research, under the same total energy intake, the protein content provided by fish is obviously higher than that of meat food.
Among many aquatic animal ingredients, we should be most familiar with fish and shrimp, especially fish. Not only can many fish be eaten by ordinary people, but also the practice is relatively simple. In addition, the fat of aquatic animals contains high content of polyunsaturated fatty acids (DHA, EPA, etc. ), and the selling point of deep-sea fish oil and cod liver oil is polyunsaturated fatty acids without cholesterol. At present, there are different views on cholesterol intake, so I won't comment here for the time being.
Although aquatic animals have high nutritional value, we should also pay attention to:
(1) should not be taken in excess. Both seawater and fresh water are inevitably polluted. For example, heavy metals and organic pollutants will be enriched in aquatic organisms. The bigger the carnivorous fish at the top of the food chain, the more harmful substances will be enriched.
(2) Prevention of parasite and microbial pollution. There are not a few such food contamination incidents, such as the hepatitis A epidemic caused by Scapharca subcrenata in Shanghai in 1988 and the snail incident.
(3) Don't casually eat unfamiliar ingredients. In particular, some toxic substances in marine aquatic animals can cause food poisoning, such as tetrodotoxin in puffer fish, which is said to be 1000 times as toxic as sodium cyanide;
(4) Some aquatic animals are inedible after death. For example, after the death of hairy crabs, a toxic substance will be produced in the body. The longer the death time, the more toxins are produced, and once eaten, there will be a risk of poisoning;
(5) Allergen problem. In 1999, allergic diseases were listed as the key research and prevention diseases by the World Health Organization (WHO) in the 2nd1century, which has been called the major global public health problem. At present, the eight main allergic foods recognized in the world are peanuts, soybeans, wheat, nuts, milk, eggs, fish and crustaceans of animal origin. Generally speaking, allergic reactions caused by eating fish, shrimp and crabs account for a large proportion, and allergic reactions caused by shellfish are also more common;
(6) The fishy smell of aquatic animals. One of the main limiting factors of aquatic products consumption is fishy smell. The fishy smell in aquatic products is formed by the interaction of many volatile substances, such as the decomposition products of endogenous trimethylamine oxide (when the content of trimethylamine oxide reaches a certain value, aquatic products will be delicious), the oxidation decomposition products of fatty acids in muscle, the metabolites of algae and microorganisms enriched in the body, and the volatile substances absorbed in muscle (the unpleasant smell similar to metal or soil is mainly produced by alcohol substances), which affect its flavor. Because the fishy smell is usually related to the expected storage process, it also reflects the freshness of ingredients to some extent.