The application of vacuum pump systems in vacuum packaging

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Vacuum packaging is a method of packaging in which items are placed into airtight containers, and then a vacuum pump system is used to create a vacuum inside the containers before sealing them, resulting in no air whatsoever within the sealed containers. Vacuum packaging is also known as reduced-pressure packaging or gas-extraction packaging. This type of packaging prevents external moisture from entering the container, and it also avoids the accumulation of humid air inside the airtight, moisture-proof packaging, which could lead to condensation when temperatures drop. When using vacuum packaging, care must be taken to avoid an excessively high vacuum level. 　　Both raw grains and processed grain products can be packaged under vacuum. Vacuum packaging not only prevents or reduces oxidation, discoloration, and flavor changes in grains, but it also inhibits the growth of certain molds and bacteria. 　　At present, the processing and preservation of foods, oils, and other similar products are still at a very basic and rudimentary level. Moreover, China’s refrigeration facilities fall short compared to those in developed countries such as the United States and Japan, which results in significant losses of agricultural products and waste of resources. Vacuum packaging can maintain the quality and nutritional components of food and agricultural products, which is why it receives much attention in the food industry. 　　In addition to controlling external temperature and maintaining sterility, vacuum packaging is more importantly used to control the appropriate gas environment for grains, in order to achieve the desired preservation effect. The main methods include mechanical extrusion and straw degassing, among others. In any case, the air inside the packaging bag must be removed first, and then it is heat-sealed. Its main features are: reducing the oxygen content inside the bag, inhibiting the growth and reproduction of molds and bacteria, and preventing the deterioration of grains, thereby achieving the purpose of preservation and maintaining quality. Furthermore, after vacuum packaging, it can resist mechanical pressure and reduce vibrations, which is beneficial for long-distance transportation as well as for sales. The mechanism of vacuum packaging: Its purpose is to reduce the oxygen content within the package, prevent the packaged food from becoming moldy or deteriorating, preserve the food’s color, flavor, and aroma, and extend its shelf life. The main function of vacuum packaging is to remove oxygen, thereby preventing food from deteriorating. The principle behind this is quite simple: food spoilage and degradation are primarily caused by microbial activity, and most microorganisms, such as molds and yeasts, require oxygen to survive. Vacuum packaging utilizes this principle by removing the oxygen from inside the packaging bag as well as within the food cells, thus depriving these microorganisms of their \"living environment\". Proof of actual testing: When the oxygen concentration inside the packaging bag is ≤1%, the growth and reproduction rate of microorganisms drops sharply; when the oxygen concentration is ≤0.5%, most microorganisms are inhibited and cease to reproduce. (Note: Vacuum packaging cannot prevent the growth of anaerobic bacteria or the food degradation and discoloration caused by enzymatic reactions; therefore, it must be used in combination with other supplementary methods such as refrigeration, flash freezing, dehydration, high-temperature sterilization, irradiation sterilization, microwave sterilization, and salting.) In addition to suppressing the growth and reproduction of microorganisms, another important function of vacuum deoxygenation is to prevent food oxidation. Since fatty foods contain large amounts of unsaturated fatty acids, they oxidize when exposed to oxygen, which causes the food to change in taste and quality. Moreover, oxidation leads to the loss of vitamins A and C, and the unstable substances in food pigments also cause their color to darken as a result of exposure to oxygen. Therefore, deoxygenation can effectively prevent food from deteriorating, preserving its color, aroma, taste, and nutritional value. In addition to the oxygen removal and preservation functions provided by vacuum packaging, the main advantages of vacuum-puffed packaging include pressure resistance, gas barrier properties, and freshness retention; these features enable food to maintain its original color, aroma, taste, texture, and nutritional value over an extended period of time. Furthermore, there are many foods that are not suitable for vacuum packaging and must instead use vacuum gas-flushed packaging. Such as crispy and fragile foods, foods that tend to clump together, foods that are prone to deformation and losing their oil, and foods with sharp edges or high hardness that can puncture the packaging. After food is packaged using vacuum inflation packaging, the pressure inside the packaging bag is higher than the atmospheric pressure outside, which effectively prevents the food from being crushed or deformed due to pressure, without affecting the appearance or printed decorations of the packaging bag. Vacuum packaging involves creating a vacuum and then filling it with nitrogen, carbon dioxide, oxygen, or a mixture of two or three such gases. Its nitrogen is an inert gas that serves to fill the space inside the bag, maintaining a positive pressure there to prevent air from outside the bag from entering. This helps to protect the food. Its carbon dioxide can dissolve in various fats or water to form carbonic acid with weaker acidity, which has the ability to inhibit microorganisms such as molds and corrosive bacteria. Its oxygen helps to inhibit the growth and reproduction of anaerobic bacteria, preserving the freshness and color of fruits and vegetables; high concentrations of oxygen enable fresh meat to maintain its bright red color.