In addition to inhibiting the growth and reproduction of microorganisms, the other important function of vacuum packaging is to prevent food oxidation, because there are a large number of unsaturated fatty acids in oily foods, which are oxidized by oxygen, making food taste and deterioration. In addition, oxidation also causes the loss of vitamin A and vitamin C. The unstable substances in food pigments are oxygenated to make the color darker. Therefore, deoxygenation can effectively prevent food deterioration and maintain its color, aroma, taste and nutritional value.
MAP modified atmosphere packaging
The main function of MAP modified atmosphere packaging, also as known as nitrogen filling packaging, gas filling packaging, 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 make food keep its original color, fragrance, taste, shape and nutritional value for a long time. In addition, many foods should not be packed in vacuum, but must be packed in vacuum. For example, crunchy and fragile food, caking food, deformable and oily food, food with sharp edges or high hardness will puncture the packaging bags, etc. After food is packed by vacuum aeration, the air pressure inside the packaging bag is stronger than that outside the packaging bag, which can effectively prevent food from crushing and deformation without affecting the appearance of the packaging bag and printing decoration.
MAP modified atmosphere packaging is then filled with nitrogen, carbon dioxide, oxygen or a mixture of 2-3 gases. Nitrogen is an inert gas, which fills the bag and keeps the positive pressure inside, so as to prevent the air outside the bag from entering the bag and play a protective role for food. Carbon oxide can dissolve in various kinds of fat or water, form weak acid carbonate, and inhibit the activity of microorganisms such as fungi and spoilage bacteria. Oxygen can inhibit the growth and reproduction of anaerobic bacteria, maintain the fresh and color of fruits and vegetables. High concentration of oxygen can keep fresh meat bright red.
Vacuum packing products
Salted products: sausage, ham, bacon, salted duck, etc; pickled vegetables: pickles, pickles, etc; bean products: tofu dried, vegetable chicken, bean paste, etc; cooked products: roast chicken, roast duck, soy sauce beef, instant food: rice, Instant Wet noodles, cooked vegetables, etc; soft canned food: bamboo shoots, sugar-water fruit, eight Bao Congee, etc.
MAP modified atmosphere packaging products
Tea, nuts, melon seeds, meat floss and so on; fried potato chips, puffed food, fruit and vegetable crisps; cakes, moon cakes and so on; various powder, food additives; various native products, precious traditional Chinese medicines; various dehydrated vegetables.
Vacuum packaging or MAP packaging are usually made of double-layer composite film or three-layer aluminum thin composite film. The thickness of the composite film is generally between 60-96 micron. The inner layer is a heat seal layer, which needs good heat sealing. The thickness is between 50-80 micron, and the outer layer is a seal layer. It needs good air tightness and printability. Brushability, a certain strength, thickness between 10-16 um. Polyethylene is commonly used as inner base material of composite film, such as high temperature cooking bag, high temperature resistant polypropylene, and stretched polypropylene, polyester and nylon as outer base material. Some foods, such as tea, milk powder and some high-fat foods, need to be packaged with light-retardant packaging to prevent food from changing color, aroma and taste due to the influence of light. The method is to compound a thin layer of aluminum foil between the inner and outer substrates, and its air tightness is also strengthened.
Vacuum or vacuum nitrogen filling packaging machine commonly used cavity type and external pumping type two models. Cavity packaging machine is divided into vacuum packaging machine and vacuum inflatable packaging machine. External pumping packaging machine has several functions, such as vacuum packaging and vacuum inflatable packaging, so it is also called multi-functional air-conditioned packaging machine. Choosing a packaging machine should be based on the shape of the packaging items, the size of the packaging capacity, the production batch, the way of packaging and other comprehensive factors. It is best to consult before purchasing.