Cooling preservation is to reduce the temperature of fish to close to freezing point, but not frozen preservation method. Generally, the temperature is between 0 and 4 DEG C, which is a widely used method to extend the storage of aquatic products. The fish can be preserved for about 1 weeks after cooling. The quality and preservation of chilled fish depends on the quality of the raw material, the cooling method, the duration of the cooling and the preservation conditions. The method of water ice cooling storage products there are two kinds of ice and ice and method.
Ice melting method
Ice melting method is a kind of fresh preservation method which can crush the ice directly to the surface of the fish. When the ice and fish body contact, the solid ice melt into liquid water, absorb a lot of heat energy, so that the fish body temperature drops rapidly, and the melting of ice water can also wash the fish body surface, remove bacteria and mucus, weight loss. The utility model can also make the fish body wet and shiny on the surface of the fish during the cooling process, so as to avoid the phenomenon of dry consumption which is often occurred by other methods.
Specific operation, the fish body cleaning - finishing fish - ice bin packing (sprinkle ice should be uniform, layer ice fish). The special fish or large fish, can go to the gills caesarean section except the visceral abdominal, ice, and ice packing (container bottom, wall and surface to sprinkle ice). A small opening at the bottom of the container is convenient to melt the ice water. Fresh ice ice amount according to temperature, thermal conditions and refrigeration equipment and chilled time. General fish and ice ratio of 1:1, high temperature, no insulation condition increases when the proportion of ice.
Water ice method
Water ice method first use ice water or clean water cooling (water 0 DEG C, seawater -1 C) and then soaked in water ice in aquatic products. Its advantage is the cooling speed. Used in rigor mortis fast or capture large amount of fish, such as sardines, chub mackerel. Water ice method is generally used for rapid cooling, water to be cooled to 0 DEG C when the product is removed, and with ice storage. Water ice law is not the preservation process, because the soaking time is too long, the fish will swell, perishable.
In the ice cooling, freshwater fish available freshwater ice, sea ice and sea water can also be used, only the sea ice fish, not available freshwater ice, mainly to prevent discoloration.