Several common fresh-keeping techniques for aquatic products

As we all know, aquatic products are highly perishable items, and once the freshness deteriorates, its value will drop a lot, and it may even lose its edible value completely and cause significant economic losses. Therefore, the corresponding fresh-keeping treatment should be taken in time for the fished aquatic products, and different storage and fresh-keeping methods should be adopted in combination with different aquatic products to meet the living needs of aquatic product processing enterprises and consumers. The storage and preservation of aquatic products is a continuation of breeding and fishing, a necessary guarantee for processing enterprises to generate income, and an indispensable and important part of the entire fishery production. What are the main aspects of the current fresh-keeping technology of aquatic products?

1. Modified atmosphere preservation method Modified atmosphere preservation technology is to change the composition of the gas in the storage or packaging under suitable low temperature conditions to inhibit the growth and reproduction of bacteria and molds, weaken the respiration of fresh aquatic products and maintain the quality of aquatic products. color, so as to achieve the purpose of anti-corrosion preservation and prolong shelf life

1. The current modified atmosphere packaging products in the domestic market are limited to fresh pork, fresh vegetables and cooked meat, etc. The modified atmosphere packaging technology of other foods has not yet achieved market application

2. The application of foreign modified atmosphere packaging technology for aquatic products is relatively mature, and there are many types of aquatic products used for packaging, including fish fillets and pieces of different fish species, shrimp, shellfish, etc. However, in China, the commercial application of modified atmosphere packaging for aquatic products is still in the research and infancy stage. Therefore, the modified atmosphere packaging technology of aquatic products has broad development prospects in China, and its research has important theoretical significance and commercial value

3. There are many studies on modified atmosphere packaging of aquatic products, most of which show that the combination of modified atmosphere packaging and low temperature can significantly prolong the shelf life of aquatic products. Studies have found that when the pearl fish is stored at 0~2°C, when the gas composition of CO2:O2 is 60%:40%, it can effectively inhibit the growth of Enterobacteriaceae and Aeromonas bacteria, and can also The psychrophilic bacteria maintain a very low growth rate, thereby extending their shelf life [5]. Under the storage condition of 0~4℃, the ratio of CO2, O2 and N2 is 60%: 20%: 20%, the preservation effect is good, and the shelf life is as high as 20d. The shelf life of Macrobrachium rosenbergii can reach 9 days when the CO2:O2:N2 is 75%:5%:20% under the storage condition of about 6℃[6]. It can be seen that the effect of modified atmosphere packaging technology on prolonging the fresh-keeping period of aquatic products mainly depends on the characteristics of raw materials, the proportion of gas composition and storage temperature, among which storage temperature is a very important factor.

2. Low-temperature fresh-keeping method Low-temperature fresh-keeping is the main fresh-keeping technology for aquatic products, which is mainly used to maintain the original freshness of the fish and the quality of the fish, and to inhibit the biochemical changes of the fish after death. In the field of low-temperature preservation, micro-freezing preservation technology, ultra-cold preservation and ice-free preservation technology can be used for fresh fish. Fluid ice is a mixture of fine ice crystals, water, and additives such as table salt or alcohol, which act to lower the freezing point of the solution and limit the size of the ice crystals. Ice crystal particles are generally between 0.01 mm and 1 mm in diameter. Because fluid ice has excellent thermophysical properties and good heat transfer performance, it can be used as both a refrigerant and a refrigerant, and it is environmentally friendly, so it is used as a phase change material in refrigeration technology. middle. Fluid ice is considered to be a good medium for cooling and preserving fresh fish. Some studies have found that when the pre-treated cicada shrimp is kept fresh in fluid ice at -1.5°C, the fluid ice system can effectively reduce the spoilage caused by microorganisms, and at the same time can inhibit the autolysis of fish. occurred, extending its shelf life to 9 days

3. Cold sterilization and preservation method Cold sterilization refers to sterilization at room temperature or a small temperature increase. Physical methods or non-physical methods can be used to ensure the safety and storage of food. Therefore, cold sterilization technology has attracted more and more attention. At present, advanced cold sterilization technologies include ozone sterilization, irradiation sterilization, ultra-high pressure sterilization, and high-voltage pulsed electric field sterilization.

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