What is modified atmosphere packaging machine? Basic introduction of modified atmosphere packaging machine

1. Preservation principle of compound modified atmosphere packaging machine. 1. Composite modified atmosphere packaging, also known as gas replacement packaging, is internationally known as MAP packaging. The principle of compound modified atmosphere packaging machine is to use compound fresh-keeping gas (mixing 2-3 gases according to the characteristics of food) to replace the air in the packaging box or bag, change the external environment of food in the box (bag), inhibit the growth and reproduction of bacteria (microorganisms), slow down the metabolic rate of fresh fruits and vegetables, and thus prolong the fresh-keeping period or shelf life of food. 2. Modified atmosphere preservation gas is generally composed of carbon dioxide (CO2), nitrogen (N2), oxygen (O2) and a small amount of special gas. CO2 gas can inhibit the growth and reproduction of most corrupt bacteria and molds, and it is the main bacteriostatic component in protective gas. O2 can inhibit the growth and reproduction of most anaerobic spoilage bacteria, maintain the color of fresh meat, maintain aerobic respiration of fresh fruits and vegetables, and maintain freshness. N2 is an inert gas and has no effect on food. As a filling gas, N2 forms a composite fresh-keeping gas with CO2, O2 and special gases. Different foods, fruits and vegetables have different components and proportions of fresh-keeping gases. Second, the key technology of modified atmosphere packaging machine. The qualified compound modified atmosphere packaging machine has two key technical indexes that must meet the corresponding requirements. These two indicators are: first, the gas replacement rate should be high, and second, the gas mixing accuracy error rate should be low. Whether the quality of compound modified atmosphere packaging equipment is qualified or not needs to be judged by these two key indicators. Modified atmosphere preservation gas is generally composed of carbon dioxide (CO2), nitrogen (N2), oxygen (O2) and a small amount of special gases. Carbon dioxide can inhibit the growth and reproduction of most spoilage bacteria and molds, and slow down the metabolism of fresh fruits and vegetables. It is the main bacteriostatic component in fresh-keeping gas. Oxygen can inhibit the growth of most anaerobic bacteria, maintain the color of fresh meat, maintain aerobic respiration of fresh fruits and vegetables, and maintain freshness. Nitrogen is an inert gas and has no effect on food. As a filling gas, it forms a composite fresh-keeping gas with carbon dioxide, oxygen and special gas. Different foods, fruits and vegetables need different components and proportions of fresh-keeping gases. When packaging food, fruits and vegetables with compound modified atmosphere packaging equipment, it is necessary to have a reasonable requirement for gas mixing accuracy error and gas replacement rate. In the standard of advanced compound modified atmosphere packaging equipment in developed countries, the gas replacement rate is required to be above 98%, and the error rate of mixing precision of fresh-keeping gas is less than 2%. This is because the above two indicators play a vital role in the preservation of food, fruits and vegetables. Examples are as follows: Example 1: When litchi is packaged in modified atmosphere, the mixing ratio of fresh-keeping gas is: oxygen (O2) concentration ratio is 4% ~ 6%; The concentration ratio of carbon dioxide (CO2) is 3% ~ 5%, and the damage concentration is 8%. The rest is nitrogen (N2) filled with gas; If O2 concentration is low, anaerobic respiration will occur, which will lead to litchi fruit fermentation and tissue necrosis. High O2 concentration or low CO2 concentration will inhibit the metabolism of litchi and shorten the shelf life. High CO2 concentration (>: 8%) will do harm to the peel and fruit, and accelerate the deterioration of litchi. Example 2: In modified atmosphere packaging of stewed vegetables (cooked food), the mixing ratio of fresh-keeping gases is: nitrogen (N2) 64% ~ 66%, carbon dioxide (CO2) 34% ~ 36%, and the gas replacement rate is ≥98%. Because many microorganisms (bacteria) need O2 for growth and reproduction, reducing oxygen content can slow down the reproduction of bacteria (except anaerobic bacteria). The experiment shows that the reasonable mixture of N2 and CO2 forms a protective layer with broad-spectrum bacteriostasis, color and taste retention on the food surface, which can keep the pickled vegetables fresh in the low oxygen environment. Therefore, when the gas mixing accuracy error rate and replacement rate can not reach the index, its bacteriostatic and fresh-keeping effect is basically ineffective. Third, the advantages of modified atmosphere preservation compared with other preservation methods. The common methods of food preservation (or quality assurance) are: (1) chemical preservation; (2) cryopreservation; (3) vacuumizing, high-temperature sterilization and quality assurance; (4) vacuumizing and filling nitrogen to keep fresh; (5) compound modified atmosphere preservation; (6) Natural biological preservation. Among the above six fresh-keeping technologies, chemical fresh-keeping is the use of chemical agents to prevent corrosion and bacteria, but consumers are limited by concerns about the side effects of preservatives; The disadvantage of cryopreservation is that the taste of food will change after freezing; The disadvantage of vacuum high temperature sterilization is that it destroys the unique taste, taste and nutrition of food; Nitrogen-filled packaging can keep the taste, taste and nutrition of food well, but the fresh-keeping period is very short. If the shelf life needs to be extended, it needs to be sterilized at high temperature after packaging, and the taste and taste change greatly. Composite modified atmosphere preservation is a brand-new preservation technology developed on the basis of the above tradition, which has certain requirements for packaging environment. Its characteristic is that it does not need high-temperature sterilization, so compound modified atmosphere preservation can ensure the taste, taste and nutritional components of the original food, and truly ensure the original taste, flavor and original appearance of the food. Fourth, the scope of use, (1) fresh fruits and vegetables, mushrooms; (2) All kinds of marinated vegetables, stir-fried dishes and fish products; (3) moon cakes, cakes and bean products; (4) Fresh livestock and poultry and aquatic products; (5) Pickles and pickled products; (6) Tea, Chinese herbal medicines and local products; (7) All kinds of foods that need to be preserved in the supermarket distribution center. 5. Fresh-keeping period of various foods (for reference): 1, fresh fruits and vegetables, mushrooms, fruits and vegetables, which still keep their metabolic respiration activities of absorbing O2 and expelling CO2 after harvest. If the O2 content in the package is reduced and the CO2 content is increased, fruits and vegetables can maintain weak aerobic respiration without anaerobic respiration, delay the aging process of fresh fruits and vegetables, reduce the metabolic rate and extend the shelf life. The fresh-keeping gases in modified atmosphere packaging of fresh fruits and vegetables are composed of O2, CO2 and N2. The shelf life of modified atmosphere packaging is determined by the variety and freshness of fruits and vegetables, such as strawberries, mushrooms, lychees, peaches and leafy vegetables. The shelf life at 0-4℃ is 10-30 days. Adopt low barrier film. 2. Preservation of cooked food products such as Chinese and western livestock and poultry, stewed vegetables, stir-fried dishes, stews and fast food. Require preservation, anti-corrosion and original flavor. The fresh-keeping gas is generally composed of CO2, N2 and other gases. After modified atmosphere packaging, the fresh-keeping gas forms a protective film on the surface of food, so as to achieve antibacterial and fresh-keeping, and maintain the nutritional components and original taste, taste and shape of food. The fresh-keeping period below 20℃ is more than 5- 10 day; Unde that condition of 0-4 DEG C, the preservation period is 30-60 days; After pasteurization (about 80℃), the shelf life is more than 60-90 days at room temperature. A high barrier film is required. Modified atmosphere packaging combined with natural biotechnology can achieve ideal results. 3. The deterioration of baked food and barbecue food is mainly mildew, so preservation needs mildew prevention and flavor maintenance. The protective gas consists of carbon dioxide and N2. The shelf life of rice flour foods such as cakes and bread at room temperature is 15-60 days; The shelf life of moon cakes at room temperature is 30-90 days; The packaging film of steamed bread needs to use high gas barrier composite plastic film to maintain the gas concentration in the packaging. With natural biotechnology, the preservation effect is doubled. 4. The modified atmosphere packaging gas of fresh livestock, fresh pigs, cattle and mutton is composed of CO2, O2 and other gases. High concentration of O2 oxidizes myoglobin in meat to oxidized myoglobin, which can keep fresh meat bright red. CO2 is used for bacteriostasis and antisepsis. The shelf life of 0-4℃ is 7-30 days. Fresh poultry were preserved with CO2, N2 and other fresh-keeping gases, and the preservation period reached 15-30 days. With natural biotechnology, it can be sold for 2-5 days at room temperature. 5. Fresh aquatic products, seafood, fresh fish and other aquatic products are perishable foods with high water content. Anaerobic bacteria is one of the spoilage factors of fresh aquatic products during low temperature storage, which produces toxins harmful to human health. The fresh-keeping gas consists of O2, CO2 and N2. Modified atmosphere packaging is the main factor of spoilage of high-fat fish, and the protective gas is composed of CO2 and N2. According to the variety and freshness, the preservation period of fresh-keeping aquatic products in modified atmosphere packaging at 0-4℃ is 15-30 days. The packaging film needs a composite plastic film with high gas barrier to maintain the gas concentration in the package. 6. Kimchi and pickled products Kimchi foods are prone to oxidation, mildew and deterioration in the air. Appropriate natural biological agents are added in the curing (soaking) process, and after modified atmosphere packaging, it can be kept fresh for 30- 180 days at room temperature. The fresh-keeping gas consists of carbon dioxide and N2. For more information, please consult Chengdu Rodipur Machinery Equipment Co., Ltd., thank you!