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When it comes to frozen food, we will think of frozen dumplings, frozen dumplings, frozen wonton and green and sweet frozen peas. These frozen foods are convenient to store and greatly improve the cooking speed, but many people still have doubts: Is frozen food really healthy?
At present, frozen food on the market is divided into chilled food and frozen food, chilled food is to reduce the temperature of the food to close to the freezing point, and storage, such as 0℃ fresh food; Frozen food is stored at a temperature lower than the freezing point, such as quick-frozen dumplings. Frozen food is now mainly fruits and vegetables, aquatic products, meat, poultry and eggs, rice and noodle products, convenience food these five categories.
Many people think that frozen food will have nutritional loss, unsanitary and other problems. As we all know, food has "life", on the one hand, they may contain biological enzymes, on the other hand, they may carry microorganisms, and the preservation of food is mainly to fight against them. Before the emergence of refrigerators, people used air drying, smoking, salting, sugar and other ways to preserve food, its essence is to kill microorganisms and biological enzymes. However, biological enzymes and microorganisms need the right temperature to function, and the lower the temperature, the lower the activity.
The emergence of refrigerators allows food to be kept fresh at low temperatures, avoids the growth of bacteria, and not only reduces the incidence of cancer, but also reduces the incidence of infectious diseases. At the temperature of minus 18 ° C in the refrigerator freezer, biological enzymes and microorganisms are basically dormant, and it is difficult to pose a threat to food. However, while the form, flavor and nutrition of food in the frozen state do not change much, the taste may not be as fresh. Taking the common frozen meat in the supermarket as an example, for meat, under the condition of low temperature, the water in the meat will be frozen into ice crystals, resulting in freezing denaturation of protein and a series of physical and chemical properties changes, which will affect the taste and may be relatively dry and hard to eat.
Of course, frozen foods still face other threats, such as oxidation and dehydration. Oxygen causes many food components to oxidize and spoil. However, under freezing conditions, the oxidation rate has been greatly reduced, coupled with the use of sealed food bags or storage boxes, sealed well, usually put more than a year will not be a problem. Dehydrating food in the freezer can make it taste bad. For example, if frozen meat is not wrapped properly, the bare surface will gradually turn white. In frozen dumplings, frozen dumplings and other food packaging can also see tiny ice crystals, these are dehydration phenomenon.
In addition, for chilled and frozen food, cold chain transportation is also critical. Many dairy companies now require fresh milk to be processed from the milk factory to the milk station within two hours, in order to ensure that the nutrients in the milk are preserved to the maximum extent possible. This is atypical food safety, related to the nutritional safety of food.