Two or three things about quick-freezing, come and see!

Two or three things about quick-freezing, come and see!

1. What is a quick freezing warehouse

　　Quick-freezing cold storage refers to a method in which food quickly passes through its largest ice crystal formation area and freezes quickly when the average temperature reaches -18°C. The temperature of the quick-freezer is generally -15℃～-35℃. Mainly used for low-temperature rapid freezing of food, medicine, medicinal materials, chemical raw materials and other items. It has the characteristics of fast cooling and good preservation effect.

　　The so-called fast freezing refers to a method in which food quickly passes through its maximum ice crystal formation zone and freezes quickly when the average temperature reaches -18°C. Food will undergo various changes during the freezing process, such as physical changes (volume, thermal conductivity, specific heat, dry consumption changes, etc.), chemical changes (protein denaturation, color change, etc.), cell tissue changes, and biological and microorganisms Changes and so on. The characteristic of quick-freezing food is to keep the original nutritional value, color and fragrance of the food to the maximum extent. That is to say, in the freezing process, the warehouse must guarantee the speed certificate so that the above-mentioned changes in the food can reach z* reversibility. Large-scale quick-freezing warehouses are part of the cold storage and are built together with other storage areas (low-temperature storage, shade storage, etc.). If you want to build a small quick-freezer, you can choose a combined cold storage, which is called an assembled type in the industry. Such an assembled cold storage saves costs, saves construction time, and has complete functions.

　　Quick freeze has the following advantages:

　　 (1) Avoid the formation of large ice crystals between cells.

　　(2) Reduce the water exudation in the cells, and less juice loss when thawing.

　　(3) The contact time of the concentrated solutes and food tissues, colloids and various components in the cell tissues is significantly shortened, and the harm of concentration is reduced to a minimum.

(4) The food is quickly reduced to below the temperature of microbial growth activity, which advantageously resists the growth of microbes and their biochemical reactions.

　　 (5) The food stays in the freezing equipment for a short time, which is beneficial to improve the utilization rate and continuity of the equipment.

　　 2. The difference between quick-freeze storage, cold storage and fresh-keeping storage

　　We usually refer to fresh-keeping storage, cold storage, and freezer storage as cold storage, but the difference between the three is still very big. According to the different products we put in, we usually divide the cold storage into the following types:

　　 1. Fresh-keeping warehouse

The storage temperature of the fresh-keeping warehouse is generally 0℃~5℃, which is mainly used to keep fresh, that is, to maintain the original quality and freshness of agricultural products for a long time, and the living products of agricultural products should not die as much as possible. In a dormant state, it reduces the loss of nutrients and maintains the quality of freshness. This is generally applied to fruits and vegetables. The current fruit and vegetable industry is planted intensively. In the process of transportation and sale, it is inevitable to use cold storage to maintain the nutrients that fruits and vegetables should have.

　　2, cold storage

　　The temperature of the refrigerator is generally -15℃～ -18℃. Generally, the food is gradually put into the cold storage from time to time. After a period of time, the temperature of the cold storage reaches -18℃, and the pick-up is also irregular and irregular. There is no specific requirement for this "period", this is a typical cold storage. For example, meat and aquatic products have higher requirements for storage temperature to keep the internals from deteriorating. In addition, they should be taken out and stored irregularly during the sale process. Generally, the cold storage in large supermarkets is cold storage.

　　3, quick freezer

　　The temperature of the quick-freezer is generally -35～-40℃, and the low-temperature refrigerator is used for the rapid freezing of materials. The temperature of the low-temperature refrigerator is generally -18～-20℃, and the materials after the quick-freezing are stored for a long time. It uses various refrigeration equipment, namely artificial refrigeration, to keep the room at a certain low temperature. Many foods such as ice cream, seafood, etc. need to be stored at -25°C in order to not deteriorate. If ice cream cannot reach -25°C when stored, its fragrance will be lost; seafood foods have much worse umami taste and taste. . The feature of the low-temperature storage is: the food is gradually put into the cold storage from time to time. After a period of time, the storage temperature of the cold storage reaches -25℃. There is no special cold storage design process and technical requirements for this period. The storage temperature of this cold storage is There are strict requirements, between -22℃～-25℃, this is a typical low temperature storage. Compared with the fresh-keeping warehouse, the frozen storage has a very different mechanism of action. Too low temperature will cause the death of food such as meat and seafood, and the freshness will be greatly affected. Therefore, for the storage of fruits, vegetables and meat, Not that the lower the temperature, the better.

　　 3. What should be paid special attention to when designing quick-freezing cold storage

　　Quick-freezing cold storage is different from other types of cold storage. Quick-freezing cold storage has excellent requirements for the refrigeration effect of the cold storage. The temperature and freezing efficiency of the quick-freezing cold storage are qualified to achieve the quick freezing effect. Which points should be paid special attention to in the design of quick-freezing cold storage?

　　 1. Understand the purpose of the cold storage and go to the cold storage site to conduct a field investigation to collect the cold storage parameters. The specific parameters of the cold storage site are very important. The actual size of the cold storage site and the surrounding environment directly affect the cold storage equipment selected for the design of the quick-freezer and the construction drawings of the cold storage.

　　 2. Choose the appropriate freezing temperature and freezing time according to the characteristics of the items to be stored in the cold storage. Different types of products have different temperature requirements. For example, tuna and other quick-freezers have different temperature requirements from ordinary fresh products. The center temperature of the frozen product must reach -50 degrees to ensure the quality of the fish. Therefore, the quick-freezer must have an accurate understanding of product characteristics and other characteristics!

　　 After confirming the above two points, select the cold storage equipment, cold storage parts and so on for the quick-freezing cold storage.

　　 Four. Precautions for installation of quick-freezing cold storage

　　 1. The foundation of the quick-freezing cold storage is affected by the low temperature, and the moisture in the soil is easily frozen. Due to the volume expansion of the soil after freezing, it will cause ground cracks and deformation of the entire building structure, severely making the cold storage unusable. For this reason, in addition to the effective insulation layer, the floor of the quick-freezing cold storage must be treated under the insulation layer to prevent the soil from freezing.

2. The installation of quick-freezing cold storage adopts stainless steel plates, embossed aluminum plates, color steel plates, and composite steel plates as panels, rigid polyurethane foam plastics as thermal insulation materials, and advanced technology to make composite wall panels, which are light in weight, high in strength, and thermally insulated Good performance, corrosion resistance, anti-aging, moth-proof, non-toxic, non-mold, and its superiority can be shown even more when used at lower temperature. The inner and outer panels of the library board are made of colored steel plates (the base material is galvanized steel). The core material of the library board is foamed rigid polyurethane or glued polystyrene foam board. Except for the ground, all components are prefabricated in a professional factory according to uniform standards and assembled on site, so the construction progress is fast and the construction period is short.

3. Quick-freezing cold storage is divided into three levels, L, D, and J. The storage temperature is 5~-5℃, -10~18℃ and -20~-23℃. Special cold storage can reach below -30℃, which can meet different needs. It is an ideal cold storage for storing meat, aquatic products, poultry and eggs, dairy products, fruits, vegetables, industrial raw materials, as well as for low-temperature test environments. It is widely used in all walks of life.

4. Convenient installation and disassembly of the quick-freezing cold storage: the storage body adopts the built-in parts in the wall of the buckle connection, which is convenient for assembly, disassembly and transportation, and the assembly and activation time is short. The installation cycle is only 1/30~1/20 of the civil cold storage, and the small and medium cold storage is generally 3 It can be delivered for use in ~5 days, which is especially suitable for mobile units such as troops, factories and mines and remote areas.

　　5. Because the quick-freezing cold storage has excellent heat preservation performance, it has a fast cooling speed and a long heat preservation time. Compared with other cold storages, it can generally save energy between 30-40%.

　　 5. Precautions for use and maintenance of quick-freezing cold storage:

　　1. Prevent the building structure from freezing and thawing cycles, freezing crisp and freezing.

　　2. Protect the floor to prevent freezing and damage.

　　3. The use of quick-freezers should be in accordance with the design requirements, give full play to the freezing and cold storage capabilities, ensure safe production and product quality, and maintain the building structure of the cold storage. The warehouse must be managed by a special team, and the responsibility is assigned to everyone, every warehouse door, every piece of equipment and tools, someone must be responsible.

　　4. The quick-freezing warehouse is made of heat-insulating materials. It has the characteristics of being afraid of water, moisture, heat, and cold running. It is necessary to keep the ice, frost, water, door and light off.

　　5. Quick-freezing warehouses must make reasonable use of storage capacity, continuously summarize and improve commodity stacking methods, safely and reasonably arrange the storage space and stacking height, and improve the utilization of cold storage. The stacking must be firm and tidy to facilitate inventory, inspection, and access.