In the field of people's lives and work, a variety of plastic vacuum packaging abounds. Lightweight, sealed, fresh-keeping, anti-corrosion, anti-rust plastic vacuum packaging from food to medicine, knitwear, from precision product manufacturing to metal processing plants and laboratories. The application of plastic vacuum packaging is becoming more and more extensive, which promotes the development of plastic vacuum packaging machines and puts forward higher requirements.
The mechanism of vacuum packaging: the purpose is to reduce the oxygen content in the package, prevent the mildew and deterioration of the packaged food, maintain the color and fragrance of the food, and extend the shelf life.
The main function of vacuum packaging is to remove oxygen, which is beneficial to prevent food spoilage. The principle is also relatively simple, because the deterioration of food mold is mainly caused by the activity of microorganisms, and the survival of most microorganisms (such as mold and yeast) requires oxygen. Vacuum packaging is the use of this principle to remove oxygen from the inside of the bag and the food cells, so that the micro-objects lose the "living environment." Experiments have shown that when the oxygen concentration in the package is ≤1%, the growth and reproduction rate of microorganisms drops sharply. When the oxygen concentration is ≤0.5%, most microorganisms will be inhibited and stop breeding. (Note: Vacuum packaging can not inhibit the deterioration and discoloration of food caused by anaerobic bacteria reproduction and enzyme reaction, so it must be combined with other auxiliary methods, such as refrigeration, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salt Pickled, etc.)
In addition to inhibiting the growth and reproduction of microorganisms, vacuum deoxygenation is another important function to prevent oxidation of foods. Because oils and fats contain a large amount of unsaturated fatty acids, they are oxidized by the action of oxygen, which makes foods taste and deteriorate. In addition, oxidation also makes Loss of vitamins A and C, unstable substances in food pigments are affected by oxygen, which makes the color darker. Therefore, oxygen scavenging can effectively prevent food from spoiling and maintain its color, aroma, taste and nutritional value.
The main function of vacuum air-packing is not only the anti-oxidation and quality-preserving functions of vacuum packaging, but also the functions of anti-pressure, gas-blocking and fresh-keeping. It can effectively maintain the original color, fragrance, taste and shape of food for a long time. Nutritional value. In addition, there are many foods that are not suitable for vacuum packaging and must be vacuum-filled. Such as crispy and fragile food, easy to agglomerate food, easy to deform and oily food, food with sharp edges or high hardness will pierce the bag. After the food is vacuum-insulated, the inflation pressure in the packaging bag is stronger than the atmospheric pressure outside the packaging bag, which can effectively prevent the food from being crushed and deformed without affecting the appearance and printing decoration of the packaging bag.
