What is vacuum packaging
Vacuum packaging, also known as decompression packaging, is to extract all the air in the packaging container and seal it to maintain a high degree of decompression in the bag. The scarcity of air is equivalent to the effect of low oxygen, so that microorganisms have no living conditions, so as to achieve fresh food and no disease. purpose of occurrence. Applications include vacuum packaging in plastic bags, aluminum foil packaging, glassware, plastic and its composite material packaging, etc. Packaging materials can be selected according to the type of items. Since fruit is a fresh food, it is still undergoing respiration, and a high degree of hypoxia will cause physiological diseases. Therefore, vacuum packaging is less used for fruit.
Concept and function
Vacuum packaging is a package that protects products from environmental pollution and prolongs the shelf life of food, which can improve the value and quality of products. Vacuum packaging technology originated in the 1940s. Since polyester and polyethylene plastic films were successfully applied to commodity packaging in 1950, vacuum packaging machines have developed rapidly.
In the field of people's life and work, all kinds of plastic vacuum packaging can be found everywhere. Lightweight, airtight, fresh-keeping, anti-corrosion, and anti-rust plastic vacuum packaging covers many fields from food to medicine, knitwear, from precision product manufacturing to metal processing plants and laboratories. The increasingly wide application of plastic vacuum packaging has promoted the development of plastic vacuum packaging machines and put forward higher requirements for them.
The mechanism of vacuum packaging: the purpose is to reduce the oxygen content in the package, prevent the mold 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 to help prevent food from deteriorating. The principle is relatively simple, because food spoilage is mainly caused by the activities of microorganisms, and the survival of most microorganisms (such as mold and yeast) requires oxygen. Yes, and vacuum packaging uses this principle to take out the oxygen in the packaging bag and food cells, so that the micro-objects lose their "survival environment". Experiments have proved that: when the oxygen concentration in the packaging bag is ≤1%, the growth and reproduction speed of microorganisms will drop sharply, and when the oxygen concentration is ≤0.5%, most microorganisms will be inhibited and stop breeding. (Note: Vacuum packaging cannot inhibit the growth of anaerobic bacteria and food deterioration and discoloration caused by enzyme reactions, so it needs to be combined with other auxiliary methods, such as refrigeration, quick-freezing, dehydration, high-temperature sterilization, radiation sterilization, microwave sterilization, salt pickled etc.)
In addition to inhibiting the growth and reproduction of microorganisms, vacuum deoxygenation has another important function to prevent food oxidation. Because oily foods contain a large amount of unsaturated fatty acids, they are oxidized by oxygen, making food taste and deterioration. In addition, oxidation also makes food The loss of vitamins A and C, the unstable substances in the food coloring are affected by oxygen, making the color darker. Therefore, oxygen removal can effectively prevent food from deteriorating and maintain its color, aroma, taste and nutritional value.
The main function of vacuum air-filled packaging is not only the function of oxygen preservation, but also the function of anti-pressure, air-blocking and fresh-keeping. It can effectively keep the original color, fragrance, taste, shape and quality of food for a long time. nutritional value. In addition, many foods are not suitable for vacuum packaging but must be packed with vacuum inflation. Such as crispy and fragile food, food that is easy to agglomerate, food that is easy to deform and lose oil, food with sharp edges or high hardness that will puncture the packaging bag, etc. After the food is vacuum-packed, the inflation pressure inside the packaging bag is stronger than the atmospheric pressure outside the packaging bag, which can effectively prevent the food from being crushed and deformed under pressure without affecting the appearance and printing decoration of the packaging bag.
Vacuum air-filled packaging is filled with nitrogen, carbon dioxide, oxygen single gas or a mixture of two or three gases after vacuum. The nitrogen gas is an inert gas, which acts as a filling to maintain a positive pressure inside the bag to prevent the air outside the bag from entering the bag and protect the food. Nitrogen dioxide could be melt easily into the fats or water, and the light carbonic acid brought up by this melting restrains some mircobials like mold and putrefactive bacteria. Its oxygen can inhibit the growth and reproduction of anaerobic bacteria, keep fruits and vegetables fresh and colorful, and high concentration of oxygen can keep fresh meat bright red. The freshness of fruits and vegetables does not lose nutrition.
Scope of application
1. Cured products: sausage, ham, bacon, salted duck, etc.
2. Pickled vegetables: pickled mustard, dried radish, kohlrabi, kimchi, etc.
3. Soy products: dried tofu, vegetarian chicken, bean paste, etc.
4. Cooked food products: roast chicken, roast duck, beef with sauce, fried food, etc.
5. Convenience food: rice, instant wet noodles, cooked vegetables, etc.
6. Soft cans: bamboo shoots in clear water, fruits in syrup, eight-treasure porridge, etc.