First, the ice layer is equivalent to the buffer layer, and the fluctuation of external temperature will be partially offset by the ice layer.
Second, the ice layer is isolated from the air, which can reduce the occurrence of oxidation and block pathogenic microorganisms. Some processing techniques also add some reducing agents to the ice to help the shrimp keep bright colors, such as vitamin C.
Third, the ice layer has played a role in water conservation. Ice will "evaporate" in a frozen state, and the scientific term is sublimation. If there is no ice, the taste will be worse if it is frozen and dehydrated for a long time. Sometimes it is treated with polyphosphate to help shrimp keep moisture and taste.
Fourthly, the solid ice layer can prevent the shrimp from being damaged during transportation, especially the fragile parts such as the head, tail and feet of the shrimp. Of course, if it is frozen shrimp, frozen scallops or something, there will be no such problem.
Frozen seafood is preserved by wrapping ice;
As long as the ice wrapped outside the aquatic products is evenly covered, a good preservation effect can be achieved. 20% and 90% ice have the same effect. It is not that the thicker the ice pack, the better the preservation effect. If left for a long time, the contents will deteriorate even if they are wrapped in ice. But there are always people who want to make huge profits. The cost of water is much lower than that of seafood, and it seems that it has become an unspoken rule in the industry for merchants to dig deep into the ice for seafood.
Let's take a look at our own ice-packed shrimp. The truth surprises you!
Therefore, we must pay attention to the quality when purchasing frozen shrimp. It is not advisable to buy shrimp products with excessive water absorption and excessive ice coating due to improper use of water-retaining agents, and shrimp products with transparent meat, abnormal tenderness and no inherent umami and flavor.