The main role of vacuum packaging is to remove oxygen, so as to help prevent food spoilage. Its principle is also relatively simple. Because the deterioration of food is mainly caused by microbial activities, the survival of most microorganisms requires oxygen, and vacuum packaging is used. This principle removes the oxygen inside the packaging bag and inside the food cells, causing the microorganisms to lose their "survival environment." Vacuum packaging does not inhibit the growth of anaerobic bacteria and the deterioration and discoloration of foods caused by enzymatic reactions. Therefore, it must be combined with other auxiliary methods such as cold storage, quick freezing, dehydration, high temperature sterilization, irradiation sterilization, microwave sterilization, salting, etc. .
In addition to inhibiting the growth and reproduction of microorganisms, another important function of vacuum deoxygenation is to prevent the oxidation of foods. Oils and fats contain large amounts of unsaturated fatty acids, which are oxidized by the action of oxygen and cause foods to taste deteriorating. In addition, oxidation also results in the loss of vitamin A and vitamin C. The unstable substances in food pigments are affected by oxygen, which darkens the color. Therefore, oxygen removal can effectively prevent food spoilage and maintain its color, aroma, taste and nutritional value. Small vacuum packaging machines have the same effect as long as they can achieve a certain degree of vacuum.
In addition to oxygen, vacuum packaging also has an inflated link. The main role of vacuum inflatable packaging in addition to the vacuum packaging has the function of oxygen removal and durability, there are mainly pressure, gas barrier, preservation and other effects, can more effectively make food long-term maintain the original color, smell, taste, shape and Nutritional value. In addition, there are many foods that are not suitable for vacuum packaging and must be vacuum filled. Such as crunchy fragile foods, easy to block foods, easily deformed oil foods, sharp edges or high hardness will pierce the packaging of food and so on. After the food is vacuum inflated and packaged by the food vacuum packaging machine, the inflation pressure in the bag is stronger than the atmospheric pressure outside the bag, which can effectively prevent the food from being crushed and deformed, and does not affect the appearance and printing decoration of the package.
The vacuum inflated package is filled with nitrogen, carbon dioxide, a single oxygen gas, or a mixture of 2-3 gases after vacuum. Nitrogen is an inert gas, which plays a filling role and maintains a positive pressure inside the bag to prevent the air outside the bag from entering the bag, thus providing a protective effect on the food. Carbon oxide gas can be dissolved in various types of fats or water to form less acidic carbonic acid, which inhibits the activity of microorganisms such as mold and spoilage bacteria. Oxygen inhibits the growth and reproduction of anaerobic bacteria, maintains the freshness and color of fruits and vegetables, and high concentrations of oxygen allow fresh meat to retain its bright red color.