Fish is rich in protein and various nutrients, and its acidity is very low, so it is easy to breed bacteria, so it should be sterilized at high temperature and high pressure of115-121℃ when canning. Such a high temperature is harmful to protein.
It has little effect, but it will cause a large loss of B vitamins. Therefore, the vitamin B 1 content of canned fish can be reduced to about half of that of fresh fish, and will be further reduced in long-term storage.
However, everything has advantages and disadvantages. High temperature and high pressure heating makes fish bones brittle and soft, and a lot of calcium is dissolved out. Therefore, the calcium content of canned fish is more than 10 times higher than that of fresh fish, among which iron, zinc, iodine,
There is no loss of minerals such as selenium. Therefore, eating canned fish has certain significance for supplementing minerals. However, if the fish used for canning are deep-sea fish contaminated by lead and mercury, the pollution will occur as the bones become brittle and soft.
Things will also be dissolved in large quantities, increasing the harm to the human body. Compared with tuna, shark, perch, swordfish, pike, marlin and cod, salmon, trout and yellow croaker are safer.
According to the different processing methods, canned fish can be divided into braise in soy sauce, tomato juice, fresh frying, steaming, smoking, oil immersion and water immersion. Generally speaking, the fat content of submerged fish is low, which can basically keep the fish natural.
The proportion of fatty acids is the most worthy choice. Soak fish in water, add seasonings and mix with vegetables to make a delicious salad. Tomato juice products have high salt content, but the acidity of tomato juice is beneficial to B vitamins.
Saving is also a better choice. Smoked fish, fried fish and braised fish are rich in flavor, but after frying, the omega-3 fatty acids of fish are destroyed, the fat content is greatly increased, and the B vitamins content is extremely high.
Part of it is destroyed and its nutritional value is not high; Toxic carcinogens such as benzopyrene may also be produced during frying and smoking, which greatly reduces food safety. Most oil immersion tanks have not been fried and smoked at high temperature, but their safety is poor.
Higher.
The shelf life of canned fish is as high as 24 months, which many consumers think is because it contains preservatives. Actually, it is not. Canning is an important food processing method, that is, putting raw materials in an airtight container with exhaust.
In the container, after high temperature treatment, all kinds of microorganisms and bacteria are killed, the activity of enzymes is destroyed, and external pollution and oxygen are prevented from entering, thus keeping the food in a stable eating state for a long time. So most canned fish are not added.
With preservatives, consumers can eat with confidence.
But when eating canned fish, you should also pay attention. It is best not to exceed 2 cans per week (each can contains about 225 grams of fish); Among them, fried fish and smoked fish should not exceed 1 can; Pregnant women, nursing mothers and young children should try not to eat. Like canned food
Fishing people should pay attention to a balanced diet, eat more fresh vegetables, fruits, beans and potatoes, improve their anti-pollution ability and avoid the possible adverse effects of eating canned fish for a long time.
When eating canned fish, it is best not to exceed two boxes a week.