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Characteristics and application of "ultra high pressure food" sterilization technology

consumers' requirements for food are generally safe to eat, stable in nature, and without additives. In order to prolong the storage time of food, it is necessary to kill most or all of the microorganisms. This treatment method is called sterilization technology. Ultra high pressure technology was the first sterilization method initiated by Meiji house food company in Japan in the 1990s. Because of its unique characteristics and advantages, it will have a broad prospect in food processing technology

according to the different temperature during sterilization, sterilization can be divided into hot sterilization and cold sterilization. Among them, cold sterilization is divided into physical sterilization and chemical sterilization according to different means of use. Physical sterilization in cold sterilization is the development trend of sterilization technology at present. Physical sterilization overcomes the shortcomings of thermal sterilization and chemical sterilization. It uses physical methods, such as the single action of high voltage, field (including electric field and magnetic field), electron, light, etc. or more than two combined actions to achieve the purpose of sterilization at low or normal temperature

ultra high pressure technology is a sterilization method pioneered by Meiji house food company in Japan in the 1990s. It is to seal the food in an elastic container or place it in a sterile pressure system and process it under ultra-high pressure above 100MPa (about 987 atmospheres) for a period of time, so as to achieve the purpose of processing and preserving food

characteristics of food processing with ultra-high pressure technology

the uniqueness of food processing with ultra-high pressure technology is that it will not raise the temperature of food, but only act on non covalent bonds, and covalent bonds are basically not destroyed, so the original color, aroma, taste and nutritional components of food have little impact. In the process of food processing, fresh food or fermented food will change color and taste due to the existence of its own enzymes, which will greatly affect its quality. These enzymes are food quality enzymes such as catalase, polyphenol oxidase, pectin methylase, lipoxygenase, cellulase, etc. these enzymes can be activated or inactivated by ultra-high pressure treatment, which is conducive to the quality of food. Ultra high pressure treatment can prevent microbial contamination of food, prolong the storage time of food, and prolong the time when food tastes delicious

comparison between ultra-high pressure sterilization technology and traditional sterilization technology

compared with traditional heating treatment of food, the advantages of high-pressure technology are:

* ultra high pressure treatment will not change the physical characteristics of food such as color, aroma and taste, and will not produce peculiar smell. After pressurization, the food still retains its original fresh flavor and nutrients. For example, strawberry jam after ultra-high pressure treatment can retain 95% amino acids, In terms of taste and flavor, it is significantly better than the jam treated by heating

* after ultra-high pressure treatment, the denaturation of protein and the gelatinization state of starch are different from that of heating treatment, so as to obtain new physical properties of food

* ultra high pressure treatment can maintain the original flavor of food, which is cold sterilization. This kind of food can be simply heated and eaten, so as to expand the market of semi-finished food

* ultra high pressure treatment is the equivalent compression process of liquid medium in a short time, so that food sterilization is uniform, instantaneous and efficient, and the energy consumption is lower than that of heating method. For example, Japan Suntory company adopts container sterilization, and the beer liquid can kill 99.99% of Escherichia coli after high pressure treatment

compared with the traditional chemical treatment of food (i.e. adding preservatives), the ultra-high pressure technology has the following advantages:

* no chemical substances need to be added to the food, which overcomes the adverse effects on the human body caused by the cross-sectional area of the chemical sample and the products generated by the interaction between the reagent and the microbial intracellular substances, and also avoids the negative effects on the human body caused by the residual chemical reagents in the food, ensuring the safety of eating

* frequent use of chemical reagents will make the bacteria resistant and weaken the sterilization effect, while ultra-high pressure sterilization is a one-time sterilization, which has obvious effect on the bacteria

* ultra high pressure sterilization conditions are easy to control, and the impact of the external environment is small, while the sterilization of chemical reagents is easy to be affected by moisture, temperature, pH value, organic environment, etc., and the effect changes greatly

* ultra high pressure sterilization can better maintain the natural flavor of food, and even improve the conformation of high molecular substances in food, such as acting on meat and aquatic products, improving the tenderness and flavor of meat products; Acting on raw milk is conducive to the ripening of cheese and the final flavor of cheese, and can also increase the yield of cheese. Chemical reagents have no such effect

process characteristics of ultra-high pressure sterilization technology

the sterilization equipment of ultra-high pressure food is not essentially different from the general high-pressure equipment, but the pressure medium is different, generally water. Because water is easy to obtain and low cost, it has no explosion risk and low energy consumption compared with gas. Generally, the pressure is 100 ~ 600MPa. When the pressure exceeds 600MPa, oil needs to be used as the pressure medium

the processing technology of solid food and liquid food is different. Solid foods such as meat, poultry, fish, fruit, etc. should be packed in pressure resistant, non-toxic, flexible and pressure transmitting soft packaging, and the processing accuracy can reach 12% Empty and sealed packaging to avoid the mixing of pressure media, and then placed in ultra-high pressure containers for pressurized treatment. The treatment process is divided into three processes: pressure boosting → pressure maintaining → pressure relief. Usually, the feeding and unloading are produced in a discontinuous manner. Liquid food, such as juice, milk, beverage, wine, etc., can be pressurized from the periphery with pressure medium in containers like solid food. The processed food can also be directly used to replace water as the pressure medium, but the sealing requirements are strict. The treatment process is pressure boosting → dynamic pressure maintaining → pressure relief. The second method can be used for continuous production

most organisms will die after being pressurized above 100MPa. Generally, the killing of parasites is similar to that of other organisms. As long as they are treated with low pressure, the virus can be killed, and the vegetative bodies of bacteria, molds and yeast can be killed at a slightly lower pressure. However, bacillus and spindle spore rods meet the requirements of large samples and full-size samples. The spores of experimental bacteria have stronger resistance to pressure than their vegetative bodies, and need higher pressure to be killed. The time of pressure treatment is inversely proportional to the pressure; The higher the pressure, the shorter the processing time. In addition, the effect of ultra-high pressure sterilization is also affected by temperature and food components

Application of ultra-high pressure food sterilization technology

since April, 1991, Japan first put ultra-high pressure product jam on the market, its unique flavor immediately attracted the high attention of governments, scientific research institutions and business circles in developed countries. Food ultra-high pressure processing technology is known as "a revolution in the food industry" and "today's top ten cutting-edge technologies in the world". It can be applied to all solid or liquid foods containing liquid components, such as fruits, vegetables, dairy products, eggs, fish, meat, poultry, fruit juice. Soy sauce, vinegar, alcohol, etc. Ultra high pressure processing technology involves food technology, microbiology, physics, sensors, automation technology and other disciplines. Due to the high cost of equipment and huge investment, at present, the domestic food ultra-high pressure processing technology is still in the research stage, and there is no mature ultra-high pressure sterilization technology has been put into food industry production, but ultra-high pressure food is extremely in line with the simple, safe, natural and nutritious consumption needs of new food in the 21st century, It is believed that it has a huge potential market and broad development prospects

source: Food partner

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