In the process of meat food production and processing, there are always two kinds of cooking processes, namely high temperature and high pressure sterilization and low temperature and atmospheric pressure sterilization. Because of the low heating temperature and the fiber of the meat, the meat is not damaged, so the taste is fresh and the various nutrients are well preserved. However, since it only kills the pathogenic bacteria, there are still a lot of spoilage bacteria, which not only has a short shelf life. And it is very easy to cause losses in the circulation field. High-temperature sterilization of meat foods due to high heating temperature causes the fibers of the meat to shrink excessively, and the taste is not as good as that of low-temperature sterilization products, but because it kills all bacteria, the internal cause of corruption is eliminated, and the shelf life can be greatly extended. High-temperature sterilization meat products, such as high-barrier packaging materials, not only store at room temperature for a long shelf life, but also transport, storage, and sales are very convenient, very suitable for the consumption needs of modern society. Therefore, vigorously developing the production of meat products that are resistant to storage at room temperature is an important product development direction of the meat food industry. The packaging industry is in line with this development trend, making a difference and innovating to meet the needs of the food industry, but also to win a broad market for itself. It is understood that the earliest package that can store meat at room temperature is canned food. It is an iron can made of tinplate, and later used glass bottles for outer packaging. Both tinplate and glass bottles have high temperature retort resistance and high barrier properties, so the shelf life of canned foods can reach more than 2 years. However, because tinplate cans and glass bottles are rigid packaging containers, they are bulky and heavy in quality. The chemical resistance of tinplate is not good, especially when acidic foods are loaded, metal ions are easily precipitated, which affects the flavor of food. In the 1960s, the United States invented the aluminum-plastic composite film to solve the packaging of aerospace foods. It used it to package meat products. It can be stored at room temperature by high temperature and high pressure sterilization. The shelf life is more than one year. The aluminum-plastic composite film acts like a can, soft and light, hence the name soft can. At present, storage of meat products with a long shelf life at normal temperature, such as the use of hard-packed containers, or tinplate cans and glass bottles; if using flexible packaging, almost all use aluminum-plastic composite film. The aluminum-plastic composite film is a laminated composite multilayer film, generally three layers, and the typical structure is a surface layer/adhesive/aluminum foil/adhesive/heat seal layer (CPP). The packaging film has the advantages of beautiful appearance and good mechanical properties, high barrier properties, high temperature cooking resistance and excellent hygienic properties, and is light and soft, and thus is widely used for packaging various foods. However, there are also some drawbacks, such as the hard and brittle texture of the aluminum foil, and the softness is not so good compared with the plastic film. In order to prolong the shelf life of meat products, high-temperature cooked meat products are packaged in vacuum body. When the aluminum foil composite material is vacuumed, since the softness of the aluminum foil is insufficient, it is difficult to completely stick it to the contents, which may cause the air in the packaging bag to be uncleaned, which may affect the preservation of the food. Therefore, when using aluminum foil for meat packaging, the thickness should not be too high. However, because its barrier property depends on the thickness and processing level, when the thickness is small, a large number of pinholes are likely to occur, so the packaging of the meat storage for storage resistance, the thickness of the aluminum foil cannot be too thin; if the aluminum foil is too thin, the aluminum foil The composite film forms a lot of wrinkles after being evacuated, and is thus prone to cracks, resulting in loss of barrier properties. Therefore, the thickness, barrier properties and softness of the aluminum foil are always three contradictions that plague the application of the aluminum foil composite film. From the market point of view, the aluminum foil composite film packaging food is opaque, so that consumers can not see the color and shape of the contents, which is not conducive to consumers' purchase. In addition, some manufacturers use the aluminum-plastic composite film to opaquely cover the defects of the product, and even falsify. , pit the consumer. Therefore, most consumers choose completely transparent packaging instead of opaque aluminum-plastic composite film packaging, resulting in poor sales of such packaging food. Aluminum-plastic composite packaging can not be heated by microwave, which is more expensive than plastic film, which affects the application of aluminum-plastic composite film. Therefore, the food processing industry has always hoped that the packaging material process can provide a barrier material similar to the aluminum-plastic composite film, but the packaging material that is both transparent and resistant to high temperature cooking replaces the aluminum-plastic composite film. Among the plastics currently used in industrial applications, only PVDC plastic films have both high barrier properties similar to aluminum foil and high temperature retort resistance. For a long time, it has been hoped to use PVDC plastic as the intermediate layer to make a composite film, which becomes a transparent and high-temperature cooking, and has a high-barrier high-temperature resistant cooking food packaging film similar to aluminum foil. However, PVDC plastic is a plastic with unique properties and extremely difficult to process, and it has many difficulties in manufacturing a composite film as an intermediate layer. The PVDC plastic film was manufactured in 1938 by a special blown film process invented by American Dow Chemical Company scientists. It has been used as a casing for meat enema for high-temperature cooking since the 1950s. The high-temperature-sterilized meat products packaged there are stored at room temperature and have a shelf life of more than 6 months. However, the PVDC film can only be heat-sealed by heating with a high-frequency medium, and cannot be heat-sealed by a commonly used resistance heating method. Therefore, for many years, the PVDC film is only used as a casing, and cannot be used as a packaging bag. In recent years, experimental studies have shown that the PVDC film can be directly composited into a composite film without any treatment by a solventless composite method. The shape of the whole film is not destroyed when the composite film is cooked at a high temperature, and is always smooth and smooth, and the combination is tight and mixed, which can fully meet the needs of high-temperature cooking food packaging. After the PVDC laminated composite high temperature resistant cooking food packaging film made by this method was put on the market, it was confirmed by experts that it is characterized by high transparency, high barrier and high temperature cooking after the aluminum-plastic composite film. Food packaging film, performance indicators have reached the international advanced level. Compared with aluminum-plastic composite film, PVDC laminated composite film is close to barrier, fully transparent and softer. It is used for vacuum food packaging of meat food. The air in the bag is very clean, which is more conducive to the preservation of meat food and microwave. Heating, and the price is only 70% to 80% of the aluminum foil composite film, so it can replace the aluminum-plastic composite film application in a considerable range. At present, the research and development of polyvinyl alcohol (PVA)-based BOPP-coated barrier film brings new hope to food packaging. This kind of barrier film has both oxygen barrier and water vapor barrier. The polymer does not contain toxic elements. The toxic element transfer phenomenon does not occur during use. The barrier material PVA is a microbial synthetic polymer material with hydrolysis and biological properties. It degrades into a double degradation mechanism and can be completely degraded into water and carbon dioxide. It is also a high-performance environmentally friendly material that can replace PVDC coated films in many ways. It is mainly used for the packaging of meat foods, quick-frozen convenience foods and non-food flavor-protecting types (such as insecticides), and has broad application prospects.
Activated Carbon For Catalyst Carrier,Coal-Based Activated Carbon For Catalyst,Activated Carbon For Catalyst,Coal Activated Carbon For Catalyst Carrier NINGXIA TIANFU ACTIVATED CARBON CO.,LTD , http://www.tjfyhxt.com
High temperature cooking bag application