Preface
Low-temperature rapid micro-freezing technology is a high-tech biotechnology that uses low-temperature ultra-low-temperature technology and newly invented micro-freezing fluid of natural ingredients to study the crystallization state of biological cells at low temperatures. It uses innovative freezing curves to directly freeze and preserve aquatic and meat products that are frozen for freshness in micro-freezing fluid. Depending on the variety and size of the object, the freezing and preservation of food is completed within 6 to 15 minutes or 15 to 30 minutes. The cell membrane in the frozen and preserved food is not frozen and is in a slightly frozen state of the organism. The frozen and preserved aquatic and meat products are kept fresh through refrigeration, so it is called low-temperature rapid micro-freezing technology, which is an innovative technology that has reached the international leading level in the field of food preservation.
Micro-freezing and fresh-keeping characteristics
Micro-freezing is a preservation technology for storing seafood on fishing boats developed in the 1960s and 1970s. Low-temperature preservation usually refers to refrigeration above 0°C, while frozen preservation refers to refrigeration below -18°C. There is an intermediate temperature zone between these two concepts, namely 0°C~-5°C. The preservation in this temperature zone is generally called intermediate temperature zone preservation. Intermediate temperature zone preservation is divided into two sections, namely ice temperature preservation and micro-freezing preservation. Ice temperature preservation refers to storage within the temperature range of 0°C to above the freezing point. Micro-freezing preservation refers to a mild freezing method of storing products at the freezing point and around -5°C, also known as overcooling or partial freezing.
Compared with traditional refrigeration, this technology can significantly extend the shelf life of aquatic products by 1.5~4 times, and the total number of bacteria and H2S generation are significantly reduced. Compared with traditional frozen storage, micro-freezing preservation can reduce the mechanical damage, cell collapse and gas expansion caused by ice crystals generated during the freezing process. It does not need to be thawed before consumption, which can reduce the loss of juice during thawing and maintain the original freshness of the food.
Micro-freezing and fresh-keeping technology
Micro-freezing technology is a typical application case of phase change material technology. It mixes extremely high latent heat phase change materials in the freezing liquid to provide continuous cooling for cells, so that cells can crystallize at a constant temperature. This uniform crystallization will not break the cell wall, and the cells are intact, thus keeping the food fresh. This is a light freezing preservation method.
Parameter
The density of micro-freezing liquid is 1300 times that of air, and its thermal conductivity is hc=4 cal/(m•h•℃), which overcomes the large thermal resistance of air. Its thermal conductivity is nearly 30 times lower than that of micro-freezing liquid. Therefore, the conversion rate of electrical energy into freezing energy and the transfer to the frozen object is 95%, and the transfer speed is extremely fast. The freezing time of a 3cm10cm6cm piece of meat in micro-freezing liquid at -30~-35℃ is 12 minutes, and the center temperature reaches -18℃. The freezing time in air at -30~-35℃ is 12 hours, and the center temperature reaches -18℃. Therefore, freezing and preserving the same tonnage of meat can save more than 40% of electricity consumption.
illustration
It is impossible to freeze food quickly by cooling air. Conventional freezing of aquatic products and meat products takes at least 2 hours, or even 12 hours. Therefore, it cannot meet the requirement that the cell membrane of frozen food is not broken. According to scientific experiments, when the liquid is cooled to -30 ~ -35 degrees Celsius, the frozen food is placed in liquid micro-freezing liquid. It only took 6 minutes for the center temperature of 31 ~ 40 shrimps (500 grams) to reach -18 degrees Celsius. According to the measurement, the cell membrane is not damaged. After thawing, it still maintains the fresh and full-price quality, and can be refrigerated for a long time. In scientific experiments, various meat products are used for trial freezing and preservation, and the result makes the meat more delicious. The lactic acid in the meat, that is, the converted glycogen substance, can completely eliminate the acid removal process in the meat processing process. Frogs, crucian carp, loach, and crayfish were used for experiments. After freezing, they were stored in a cold storage at -18 degrees Celsius for 7 days, and slowly thawed at a certain temperature. Some of the test organisms can be revived. After freezing, shrimp, fish and meat products were examined by cell sections, and the cell membranes were well preserved. There was no soluble protein and cell protoplasm exudation during thawing, so the thawing water was clear and clean.
Low-temperature rapid micro-freezing technology completes the freezing and preservation process of meat in a very short time. At the same time, during the rapid freezing process, the cell membrane of the frozen object does not break, and it is converted into polysaccharides through a rapid physical reaction. Innovative high-tech biotechnology is used to change traditional processes such as acid removal. During thawing, no soluble protein seeps out of the meat, and the thawed meat still maintains its fresh quality, maintaining the full price nutrition of meat products, and the meat is more tender when eaten. At the same time, processing companies have overcome the problem of meat dry loss in conventional freezing, and achieved meat freezing and preservation without dry loss, full price, electricity saving, and labor saving.
Experimental Procedure
- Prepare the micro-freezing solution
- Put the fish into the micro-freezing solution
- The fish is instantly frozen
- Put the fish in a plastic bag and put it in the refrigerator
- Thaw the fish after two hours
- The fish is alive and kicking again
Rapid low temperature micro-freezing technology for aquatic food
The inspiration of nature and scientific experiments conducted repeatedly over many years have confirmed that the temperature of food cells in the freezing and preservation process is set between -30 and -35℃. However, due to the heat transfer problem of food objects, it is impossible to quickly freeze food with cooling air. Conventional freezing of aquatic products and meat products requires at least 2 hours, or even 12 hours. Therefore, it cannot meet the requirement that the cell membrane of the frozen food is not broken. According to scientific experiments, when the liquid is cooled to -30~-35℃, the frozen objects are placed in liquid micro-freezing liquid. It only takes 6 minutes for the center temperature of 31~40 (500 grams) shrimps to reach -18℃. According to the measurement, the cell membrane is not damaged. After thawing, it still maintains the fresh and full-price quality, and can be refrigerated for a long time. In scientific experiments, various meat foods are used for trial freezing and preservation, and the results make the meat more delicious. In addition, the lactic acid in the meat, that is, the inverted glycogen substance, can completely eliminate the acid removal process in the meat processing process. Frogs, crucian carp, loach, and crayfish were used for experiments. After freezing, they were stored in a cold storage at -18℃ for 7 days, and the temperature was slowly adjusted to thaw. Some of the experimental organisms were able to revive. Shrimp, fish, and meat products were frozen and tested by cell section. The cell membrane was well preserved. There was no soluble protein and cell protoplasm exudation during thawing, so the thawing water was clear and clean.
The freezing point of fish varies according to the species, as follows: freshwater fish -0.5℃, freshwater fish -0.75℃, migratory marine fish -1.5℃, low-dwelling marine fish -2℃. Judging from the different micro-freezing methods used by various countries for different fish species, the micro-freezing temperature of fish is mostly -2℃ to -3℃.
Rapid cryogenic freezing technology in the biological field
1: The specially designed ILF freezing system can meet the needs of the Center for Disease Control and Prevention and the public security forensic doctor to preserve samples for a long time and ensure the authenticity of legal evidence. It is easy to use, has 24-hour standby, high technology content and low operating cost.
2: Currently, we are cooperating with relevant institutions to conduct research on the application of human organs, skin, animal sperm, eggs, plasma, stem cells and other biological fields. Low-temperature rapid micro-freezing technology will make a significant contribution to human life sciences.
Rapid low temperature micro-freezing technology for fruits and vegetables
Rapid micro-freezing and preservation can keep the cells of fruits and vegetables intact, and some fruits and vegetables are converted into polysaccharides during the rapid freezing process, which makes the fruits and vegetables taste better and the nutrients will not be lost.
1: Green beans are frozen for 3 minutes by low-temperature rapid micro-freezing technology, and after 6 months of refrigeration, when thawed and eaten, the color is the same as when they were just peeled out of the pods, which is green. No heating and killing processes are required, saving 60% of the energy consumption in green bean processing.
2: Garlic heads, tuberous vegetables, tomatoes and other vegetables can be frozen and preserved for a long time by low-temperature rapid micro-freezing technology.
3: Lychees, cherries, bayberries, longans, mulberries, Leliguo, Hami melons, etc. can also be processed and preserved by low-temperature rapid micro-freezing technology. After grapes are treated with low-temperature rapid micro-freezing technology for 3 minutes, the sugar substances in the grapes can be increased, and high-quality commercial wines like ice grapes can be produced.
Application of Micro-freezing Technology and Its Economic Efficiency
In the low-temperature rapid micro-freezing technology for aquatic products and meat, the invention and innovation of the two patents have been combined into a micro-freezing production line, which has been introduced and used by enterprises in Japan, South Korea, Guangdong, Guangxi, Hubei, Zhejiang, Hebei and other countries and regions, filling the gap that many aquatic foods in my country cannot produce frozen and fresh raw aquatic products. Terminal products, such as raw shrimp, raw fish fillets, crispy grass carp, etc., are exported to Japan and the United States, which has achieved high economic benefits for enterprises.
The technical and economic advancement of introducing low-temperature rapid micro-freezing technology for aquatic products and meat (abbreviated as ILF) and introducing micro-freezing production lines.
- Zhongshan City, China introduced ILF to carry out shrimp food preservation processing, and continuous liquid freezing solved the preservation problem of Guangdong’s specialty crispy grass carp.
- Enterprises in Guangdong, Zhejiang, Guangxi, Hubei, Hebei and other places introduced ILF to specialize in the production of raw shrimp and raw fish foods for export to Japan and the United States.
- The technical and economic application of ILF in meat food processing enterprises.
Forecast
Micro-frozen products not only maintain the original flavor and freshness of the product, but also ensure the integrity of the product cells. Therefore, micro-frozen fresh-keeping products will have broad market potential. At present, the cold chain system from farm to table is still very imperfect, and temperature fluctuations occur frequently, resulting in a decline in product quality and a shortened shelf life. In order to promote the application and development of micro-frozen preservation technology in food circulation, it is necessary to establish a micro-frozen circulation network system including micro-frozen workshops, micro-frozen cold storages, micro-frozen transport vehicles, and micro-frozen display cabinets, and conduct full-process temperature and quality monitoring, so that the products are always in a micro-frozen state from the processing workshop to the supermarket.
