Application of the hottest PVDC in chilled meat pa

2022-08-04
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Application of PVDC in chilled meat packaging

China is a big meat country in the world. Since the 1990s, China's meat processing industry has achieved unprecedented development. The meat output has ranked first in the world for many consecutive years. Various meat products (Chinese and Western) have spread all over the cities and villages, and large meat processing enterprises such as Chundu, Shuanghui, Jinluo, Yurun and delis have emerged. These large-scale enterprises have participated in market competition and continuously developed meat products suitable for Chinese tastes, which has enriched the variety of meat products and adapted to the needs of different consumer groups

as for raw meat, as early as the 1950s and 1960s, developed countries in Europe and the United States have gradually given up hot meat and began to research and promote chilled meat. The advent of chilled meat is known as the "revolution of meat consumption". At present, more than 90% of the consumption trend of raw meat in the world is chilled meat

in recent years, with the rapid development of China's economy and the acceleration of internationalization, China's meat consumption structure has also changed significantly. Raw meat shows a development trend from hot fresh meat to frozen meat, and from frozen meat to cooled meat. Industry experts assert that chilled meat will become the mainstream of raw meat consumption in China in the new century

chilled meat

chilled meat: also known as cold fresh meat and assured meat, it refers to fresh meat that is slaughtered in strict accordance with the requirements of the quarantine and inspection system, which is rapidly cooled and reduced to 0 ~ 4 ℃ within 24 hours, and is always kept within 0 ~ 4 ℃ during subsequent processing, circulation and sales

although the cold chain in China has tended to be perfect and standardized, the 0 ~ 4 ℃ used for cold storage of chilled meat can not completely inhibit the growth and reproduction of some psychrophilic microorganisms. Therefore, the shelf life of chilled meat is short, and the surface browning and juice loss are serious. The storage period is generally 3 ~ 7 days, which can not fully meet the needs of market circulation. In addition, China's traditional consumption habits affect the promotion of chilled meat in China

how to prolong the fresh-keeping period of chilled meat is the key to the development of chilled meat. For this reason, food experts at home and abroad have conducted a lot of scientific research. Many new meat preservation technologies, such as preservative preservation, radiation preservation, low water activity preservation and so on, have been published frequently. The new packaging technology is also very important to prolong the fresh-keeping effect of chilled meat

according to authoritative data, the variety and quality of meat products in China are far behind the world's advanced level. One of the main reasons is that the lag of meat packaging technology restricts the development. The author believes that the selection of appropriate packaging materials and packaging technology can play a very significant role in improving the fresh-keeping period of chilled meat and ensuring the hygiene and quality of meat

at present, the main form of fresh meat packaging technology in Europe, America and other countries is

1. modified atmosphere packaging technology

also known as gas replacement packaging, which changes the atmosphere in the packaging by replacing the gas environment in the packaging with appropriate gas composition, so that the meat is in an environment with different air composition, so as to inhibit the growth and reproduction of microorganisms and extend the packaging of fresh-keeping period. High oxygen packaging (also known as red meat packaging) and anaerobic packaging are mainly used for meat segmentation, and low oxygen packaging is mainly used for carcass. In developed countries in Europe and the United States, CO2, N2 and O2 are mainly used in different proportions. CO2 mainly inhibits the growth of bacteria and fungi, especially at the initial stage of bacterial reproduction. The bacteriostatic effect is the best at low temperature and 20 ~ 30% concentration; N2 mainly prevents oxidative rancidity and inhibits the growth of mold; O2 is mainly oxygenated myoglobin, which keeps meat bright red and inhibits the propagation of anaerobic bacteria

2. vacuum packaging technology

by means of vacuum pumping, the packaging is close to the meat, which can inhibit the water seepage of the meat, block the oxygen, inhibit the bacterial reproduction, and improve the safety of the meat. Vacuum body fitted packaging and heat shrinkable packaging are widely used in the packaging of segmented meat, and thermoforming stretch packaging is applied abroad

both modified atmosphere packaging and vacuum packaging have a common feature, that is, the materials are required to have high barrier, so as to prevent the invasion of external air and bacteria, internal moisture loss, etc., and improve the hygiene and safety of meat products. The materials selected for these packages are the key to whether the packaging effect is obvious or not. Their common feature is the selection of polyvinylidene chloride (PVDC) high barrier packaging materials

high barrier packaging materials

at present, the three recognized high barrier materials in the world are PVDC, ev-oh and pan. The three kinds of materials are copolymers. Ev-oh is better than PVDC, and PVDC is better than pan in oxygen barrier; Ev-oh is better than PVDC and PVDC is better than pan in terms of water vapor barrier. However, under high humidity conditions, ev-oh is very easy to absorb moisture due to the -oh group in its molecular structure, and the barrier will be significantly reduced. At the same time, the barrier property of pan material decreases obviously with the increase of ambient humidity. PVDC is one of the best comprehensive barrier materials in the world

pvdc is the English abbreviation of polyvinylidene chloride, which is a high molecular compound formed by polymerization of vinylidene chloride monomer (hereinafter referred to as VDC). In the late 1930s, Dow Chemical Company of the United States began to conduct extensive research on the copolymerization and processing of VDC and VC. In 1947, it realized industrial production with the trade mark of saran. Japan began research in 1948 and put into industrial production in 1954. Asahi Kasei and Wu Yu have successively carried out production and Research on PVDC. In the 1980s, Dow Chemical Company of the United States launched vdc-ma series. Since the 1990s, some western multinational companies with strong strength in testing the thickness, width, edge crack, structure and mechanical properties of experimental plates have increased the development and application of other copolymers of vinylidene chloride, such as copolymerization of vinylidene chloride with methyl acrylate, methacrylic acid and acrylonitrile, Thus, the production and development of vinylidene chloride resin have entered a new stage. At present, the main manufacturers of PVDC resin in the world are Dow Chemical Company in the United States, Wuyu Chemical Co., Ltd. in Japan, Asahi Chemical Co., Ltd., Solvay in Belgium, etc

pvdc is an excellent food packaging material, especially resistant to high temperature cooking and good barrier to oxygen, steam and various odors, which is unmatched by other plastics. At the beginning, it was mainly processed into film, which was used in the packaging of weapons and ammunition during World War II. It was gradually transferred to food packaging in the late 1950s and early 1960s, and then gradually applied to drug packaging and other fields. With the acceleration of modern packaging technology and the pace of modern people's life, the popularity of microwave ovens and refrigerators, and the consumption of fresh-keeping film increased sharply, making the application of PVDC more popular. EVOH, a new high barrier material appeared in the 1980s, once threatened the development of PVDC because of its recyclable performance and unique environmental protection effect. However, its barrier property against humidity decreased significantly. It is necessary to protect EVOH from humidity to achieve a high oxygen barrier effect, which greatly limits its application range

pvdc is the only large-scale industrialized plastic in the world that can withstand high temperature cooking and has high barrier properties. The film made with it has been widely used in China, of which the biggest use is as sausage casing. These applications fully show the performance and unparalleled advantages of PVDC materials, which can be customized according to domestic and international standards provided by users. However, PVDC is also a plastic that is difficult to synthesize and process. Only a few large companies in the world have these synthesis and processing technologies, so the output is small, the price is expensive, and the scope of promotion and application is narrow. The annual output of the world is only more than 100000 tons. However, because of its unique performance, it occupies an important position in the plastic packaging material industry, especially in the food packaging industry. Using it as an intermediate layer to manufacture multi-layer composite materials is the frontier of technological progress and technological innovation in the plastic packaging industry

China began the research on the practical application of PVDC resin in the early 1980s. First, the birth of ham sausage introduced PVDC film into China. Then, represented by Luoyang Chundu, it broke the blockade of the United States and Japan, introduced the processing technology and equipment of PVDC film, and created China's PVDC film processing industry. In the late 1990s, a group of packaging materials researchers represented by Mr. Shude, a famous PVDC film processing expert in China and senior engineering teacher of Luoyang Chundu, tried to apply PVDC plastics to other packaging fields and achieved success

pvdc is used to pack chilled meat

PVDC plastic is used in the packaging of chilled meat. It is not a pure PVDC film, but a multi-layer coextrusion film with PVDC as the barrier layer. It is made of vinylidene chloride, methyl acrylate, methacrylic acid and acrylonitrile copolymer as the barrier layer, together with other wear-resistant materials and heat sealing materials through coextrusion process. This film has extremely high oxygen barrier property, with oxygen transmittance <50 ml/m2, ATM, 24h, 23 ℃, 65%rh, and extremely high water vapor barrier property, with water vapor transmittance <5g/m2, ATM, 24h, 23 ℃, 90%rh. At present, pe/tie/pvdc/tie/pe and pe/tie/pa/tie/pvdc/tie/pe five layer and seven layer structures are commonly used internationally. The multi-layer co extruded high barrier film used in modified atmosphere packaging technology is mainly cast and blown, which does not have shrinkage, and the thickness is generally 90 ~ 150 μ m. With high transparency and puncture resistance, it can inhibit microbial reproduction by changing the gas environment inside the package. Vacuum shrinkable packaging is mainly made by multi-layer coextrusion and double bubble blowing. PVDC is used as the barrier layer. After coextrusion with other special materials by double bubble method and off-line treatment, the shrinkage rate of the product is about 35 ~ 45%. The shrinkability of the shrinkable film is used to make it close to the surface of meat products and prevent water seepage. The thickness is generally 50 ~ 90 μ m。 The PVDC coextrusion films with these structures have been produced and researched by enterprises such as Luoyang Chundu, Hebei Qinhuangdao and Xingtai in China since the late 1990s, but they have not been localized so far. A small number of Chinese enterprises are using high barrier packaging materials, which are completely dependent on imports

by using PVDC coextrusion film to pack chilled meat, the fresh-keeping period of meat can be extended, the sales field of meat processing enterprises can be expanded, and the long-distance markets at home and abroad can be covered. For export-oriented enterprises, the storage period of meat products in long-distance transportation should not be strange to students, and the quality of meat products can be guaranteed. According to the survey, at present, less than 1% of the chilled meat production and processing enterprises use high barrier plastic packaging materials, which are only used in the export packaging of beef and mutton

conclusion: with the gradual maturity of the domestic chilled meat market, hot fresh meat and frozen meat will gradually withdraw from the mainstream of raw meat consumption, and chilled meat will "enter the homes of ordinary people" at an unprecedented rate of development. For domestic raw meat processing enterprises, new requirements have also been put forward in terms of packaging. We are glad to see that some domestic raw meat export-oriented enterprises and packaging production enterprises have keenly captured this information and have begun to use and produce this new high barrier packaging material. Grassland Xingfa, Changchun Haoyue, Baoquanling, Hua'an cattle industry, etc. Qinhuangdao jiaruite Plastic Technology Co., Ltd., Zhengzhou Baolan Packaging Technology Co., Ltd. and other enterprises committed to the development and research of new packaging products in China are stepping up the development of such packaging materials. In October, 2005

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