[China Packaging Network News] Chinese packaging network experts pointed out that the composite modified atmosphere packaging, internationally known as map packaging, the use of fresh air conditioning is generally composed of co2, n2, o2 and a small amount of specialty gases. Co2 can inhibit the growth and reproduction of most aerobic spoilage bacteria and molds; o2 inhibits the growth and reproduction of most anaerobic spoilage bacteria; maintains the color of fresh meat, maintains oxygen enriched respiration and freshness of fresh fruits and vegetables, and n2 acts as a filling gas. The compound gas composition ratio is properly selected according to the type of food, preservation requirements, and packaging materials to achieve high preservation quality of the packaged food, good maintenance of nutrient content, ability to truly achieve the original traits, and delay the shelf life of preservation.
Composite modified atmosphere fresh-keeping packaging has been widely used at home and abroad
I. Modified atmosphere packaging of fresh fish and shrimp
The deterioration of fresh aquatic products and marine fish is mainly caused by bacteria decomposing trimethylamine oxide of fish meat to release trimethylamine with a bad smell, rancidity of fatty oxidation of fish, enzyme degradation of fish in fish, softening of fish, bacteria on the surface of fish (aerobic Escherichia coli , anaerobic Clostridium) produces toxic toxins that endanger human health.
The gas used for the modified atmosphere packaging of fish is composed of co2, o2, and n2, in which the concentration of co2 gas is higher than 50%, which inhibits the growth of aerobic bacteria and molds without causing the leakage of fish; the concentration of o2 is suppressed by 10%-15%. Oxygen bacteria multiply.
The fish's cockroaches and entrails contain a large amount of bacteria and must be removed, cleaned, and disinfected before disposal. Since CO2 is apt to seep out of plastic film, fish-modified packaging materials need to use a composite plastic film with high gas barrier properties, which can last 15-30 days at 0°C-4°C. Tuna uses 35%-45% of co2/55%-65%n2 gas fresh-keeping packaging shelf life of 6 days.
The deterioration of shrimp is mainly caused by microorganisms. Its intrinsic enzyme action causes the shrimp to darken. The use of modified atmosphere packaging can save fresh grass shrimp. The shrimp was soaked in a preservative solution of 100 mg/l lysozyme and 1.25% sodium bisulfite, and then air-adjusted in a package filled with 40% of co2 and 60% of n2 gas mixture. The shelf life of the shrimp was longer than that of the control sample. 22 Day is 6.5 times the shelf life of the control sample.
Second, poultry fresh meat modified atmosphere packaging
Fresh-keeping pigs, sheep, and beef have fresh-keeping packaging for fresh meat and can preserve fresh meat. The gas for modified atmosphere packaging consists of o2 and co2. The gas composition varies according to the type of meat.
The gas composition of pork modified atmosphere packaging is 60%-70% o2 and 30%-40% of co2. The shelf life at 0°C-4°C is generally 7-10 days (including cooling at 0°C-4°C after slaughter) 24h: Cooled pork with ap active substance lost, texture soft and aroma, and good palatability.
Poultry modified atmosphere packaging is mainly preservation and preservation. The gas used for fresh keeping is composed of co2 and n2, and the poultry meat is packaged with 50%-70%co2/50%-30%o2 at the shelf life of 0°C-4°C for 14 days.
In meat modified atmosphere fresh-keeping packaging, the use of high-concentration o2 allows fresh meat to remain bright red and more vivid, in the absence of oxygen the meat is lavender, such as with the preservation of gas co2, n2, the color of the meat is lavender, fresh Up to 30 days. Fresh meat packaging materials also require the use of composite plastic packaging materials that have high barrier properties to gases.
Third, the fresh-keeping packaging of baked goods and cooked food products
Baking foods include cakes, cakes, biscuits, breads, etc. The main ingredient is starch. Corruption caused by bacterial molds, etc., rancid deterioration due to oxidation of fats, aging and hardening of the starch molecular structure, etc. cause deterioration of foods. The gas used for the modified atmosphere packaging of such foods consists of co2 and n2.
Cream-free cakes are kept fresh for 20-30 days at room temperature. Moon cakes and pudding cakes have a high-barrier property and the preservation period can reach 60-90 days at room temperature. Soybean products and livestock and poultry cooked meat products filled with co2 and n2 can effectively inhibit the growth of coliform bacteria. Fresh-keeping at room temperature 20 °C -25 °C 5-12 days, after conditioning by 85 °C -90 °C sterilization at room temperature preservation about 30 days at 0 °C -4 °C refrigeration temperature preservation 60-90 days.
Fresh fruits and vegetables modified atmosphere fresh-keeping packaging
After harvesting, fruits and vegetables can still retain oxygen, excrete the metabolism of co2, and consume nutrients. The preservation of fruits and vegetables is to reduce the breathing progress by reducing the o2 content in the environment and low-temperature storage, eliminating the co2 produced by breathing to delay ripening and aging of fruits and vegetables to achieve the preservation effect.
The modified atmosphere packaging gas of vegetables is composed of o2, co2, and n2, and the fruits and vegetables are packed in air-permeable film, filled with low o2 and high co2 and mixed gas is sealed after replacement, so that the o2 content in the package is lower than air and the accumulation of co2 is higher than air , Gas exchange through the membrane, to achieve the preservation of the environment conducive to fruits and vegetables, to maintain a slight aerobic respiratory balance.
Most fruits and vegetables are packed with 5%o2, 5%co2, and 90%n2 mixing ratios, and they have a longer shelf life at 6°C-8°C. Modified atmosphere packaging is used for preservation and preservation of litchi. Treatment of litchi fruit with 10%co2+90%n2and20%co2+80%n2 for 24hr can not only achieve the purpose of preservation, but also improve the fruit's good fruit rate, keep the peel red, and does not affect the nutritional composition. , With high co2 and low oxygen conditions combined with ozone treatment (4.3mg/m3 concentration) and edible thin coating, can extend the shelf life of strawberries 8-10 days.
China Packaging Network experts told readers that American scientists had used modified atmosphere packaging experiments on mangoes to peel and cut mangoes, use oxygen packaging, and mixed gas (n286%, co210%, o24%) packaging and vacuum packaging. The mixed-gas packaged mango has the longest shelf life. During the storage period, the mango's color, texture, and other appearance effects are good, and the damage caused by microorganisms is minimal.
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