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Application of modified atmosphere packaging technology in beef and mutton industry
Modified atmosphere fresh-keeping packaging is also called MAP or CAP abroad, and domestically called modified atmosphere packaging or replacement gas packaging, inflatable packaging. It is to use packaging materials with gas barrier properties to package food. According to the actual needs of customers, a certain proportion of O2+CO2+N2, N2+CO2, O2+CO2 mixed gas is filled into the packaging to prevent food from occurring in physical, chemical, biological and other aspects. Decrease in quality or slow down the rate of decline in quality, thereby extending the shelf life of food and increasing the value of food.
As a food packaging technology, modified atmosphere packaging has a long history. As early as the 1930s, Europe and the United States began to study the use of CO2 gas to preserve meat products; in the 1950s, N2 and CO2 gas replaced cans of beef and cheese. In the 1960s, due to the development of various air-tight plastic packaging materials, many foods such as meat, fruits, vegetables, cakes, tea and dairy products have successfully adopted the gas replacement packaging technology; 70 In the 1990s, inflatable packaging for fresh meat was used in Europe and the United States, and modified atmosphere packaging has flourished around the world since then.
Modified Atmosphere Application
Modified atmosphere packaging is also called MAP or CAP abroad, and domestically called modified atmosphere packaging or replacement gas packaging, inflatable packaging. Commonly used gases are N2, O2, CO2, mixed gas O2+N2 or CO2+N2+O2 (ie MAP). Modified atmosphere packaging technology can be used to preserve the freshness of all kinds of food, prolong the shelf life of food, and enhance the value of food.
Application of modified atmosphere packaging technology CO2 in food packaging
A Swedish company has introduced packaging bags, containers and storage rooms filled with CO2 gas to store meat. High concentration of CO2 can hinder the reproduction of microorganisms such as aerobic bacteria and mold, prolong the stagnation period and exponential growth period of microorganism growth, and play the role of anti-corrosion and anti-mold. This method enables beef and mutton to be stored for 120 days without freezing treatment, and longer storage time if re-pressure treatment. This method has attracted great attention from meat exporting countries such as the United States and Australia.
Recently, American experts have adopted new technology to make plastic packaging materials with CO2. That is, using a special catalyst, CO2 and ethylene oxide (or propylene oxide) are mixed in equal amounts to make a new plastic packaging material, which is characterized by glass-like transparency and airtightness; similar to polycarbonate and polyamide Resin; it will not be completely decomposed into gas at 240 ° C; it has the characteristics of biodegradation and will not pollute the environment and soil.
my country has successfully used nanotechnology to catalyze CO2 synthesis of degradable plastics. That is, the catalyst used to make plastics from CO2 is "smashed" to the nanometer level to realize the polymerization of catalytic molecules and CO2, so that each gram of catalyst can catalyze about 130 grams of CO2, and synthesize a new packaging material containing 42% CO2. As an environmentally friendly material with excellent degradability, it has broad application prospects.
Modified Atmosphere Packaging Machine
Application of modified atmosphere packaging technology nitrogen in food packaging
Nitrogen (N2) is an ideal inert gas and has special effects in food packaging: it does not react chemically with food and is not absorbed by food, can reduce the oxygen content in the packaging, and greatly inhibit the growth and reproduction of bacteria, molds and other microorganisms , slow down the oxidative deterioration and spoilage of food, so as to keep food fresh. Nitrogen-filled packaged food can also prevent the food from being squeezed and broken, the food sticking or shrinking into a ball, and maintaining the geometric shape, dryness, brittleness, color, aroma and other advantages of the food. At present, nitrogen-filled packaging is rapidly replacing traditional vacuum packaging, and has been applied to fried potato chips and fries, oil-cooked food, etc. Favored by consumers, especially children and youth, nitrogen-filled packaging is expected to be used in more food packaging.
The United States uses N2 to increase the strength of beverage cans made of thin aluminum materials. Before the beverage can be canned, nitrogen gas is dissolved in the beverage; after the beverage can is sealed, the nitrogen gas is released from the beverage, forming a pressure on the can wall, making the beverage can. It is equivalent to an inflatable can, thus increasing the strength of the beverage can, and the effect is obvious. The canned beverage will not be damaged during transportation, stacking or on the shelf, and will not affect the quality of the beverage. This method can also be used for beverage packaging made of polyester plastics.
In the application of N2, the purity and quality of N2 must be paid attention to. The purity of nitrogen gas separated from compressed air by membrane separation or pressure swing adsorption can reach more than 99.9%. The purity of N2 used in food packaging must reach pure nitrogen level (ie safety level).
Application of modified atmosphere packaging technology compound gas in packaged food
The composite modified atmosphere fresh-keeping packaging is collectively referred to as MAP packaging internationally, and the modified atmosphere fresh-keeping gas used is generally composed of CO2, N2, O2 and a small amount of special 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; maintain the color of fresh meat, maintain the oxygen-rich respiration and freshness of fresh fruits and vegetables; N2 is used as filling gas. The composition ratio of the composite gas is properly selected according to the type of food, preservation requirements and packaging materials to achieve the effect of high preservation quality of the packaged food, good preservation of nutrients, truly achieving the original properties and delaying the shelf life of preservation.
Composite modified atmosphere fresh-keeping packaging has been widely used at home and abroad.
Fresh Meat Modified Atmosphere Packaging Machine
The modified atmosphere packaging machine for fresh meat should not only keep the original red color of the fresh meat but also preserve the freshness. The gas composition of modified atmosphere packaging of beef and mutton is 60%-70% O2 and 30%-40% CO2, and the shelf life at 0℃-4℃ is generally 7-10 days (including slaughtering at 0℃-4℃ temperature) Cooling for 24h makes the ATP active substances lose, the texture becomes soft and fragrant, and the palatability of the cooled beef and mutton is good).
In the modified atmosphere packaging machine for meat, the use of high concentration of O2 can make the fresh meat keep bright red and more vivid, and in an oxygen-deficient environment, the meat will be lavender. The shelf life can be up to 30 days. Fresh meat packaging materials also require the use of composite plastic packaging materials with high gas barrier properties.
Several protective gases for food modified atmosphere fresh-keeping packaging machine
Commonly used protective gases at home and abroad are CO2 (carbon dioxide), O2 (oxygen), and N2 (nitrogen).
Their respective functions are:
CO2: It is an antibacterial gas agent that inhibits the growth and reproduction of bacteria.
(1) The better bacteriostatic effect is in the lag period of the bacterial growth curve (the bacterial inhibition index is about 100/100g);
(2) Easily soluble in water and fat at low temperature;
(3) It has bacteriostatic effect on most aerobic bacteria, but is ineffective on anaerobic bacteria and yeast.
(4) Usually the lower concentration for inhibiting bacteria is 30%.
O2: It works in three ways:
(1) Inhibit the growth and reproduction of anaerobic bacteria;
(2) Maintain the red color of fresh beef and mutton;
(3) Maintain fresh fruit and vegetable metabolism and aerobic respiration.
N2: Inert gas, not working with food, only as filling gas for mixed gas.
Modified atmosphere packaging costs more than vacuum packaging
Modified atmosphere packaging has similar requirements to vacuum packaging materials. The increased cost of modified atmosphere packaging is mainly gas costs. Gas cost calculation:
Among the three gases, the price of carbon dioxide is higher. The pressure of each carbon dioxide high-pressure steel cylinder is 13-15MPa, the cylinder volume is about 40 liters, the gas weight is about 10Kg, and the inflation price is 30 yuan/bottle. For example, the mixed gas is all calculated as carbon dioxide, and the weight of each liter of gas with a pressure of 0.1MPa is about 3g, and the cost is (30/10*1000)*3=0.009 yuan/liter. That is, the cost of each liter of gas with a pressure of 0.1MPa is less than a penny.
Application of Modified Atmosphere Preservation Packaging in Fresh Meat
The modified atmosphere fresh-keeping packaging of fresh meat is mainly used for beef and mutton. The meat is red, also known as red meat packaging. It is required to maintain the red color of fresh meat and to preserve freshness; the meat of red meat contains bright red oxygenated muscle red. It can keep the flesh color bright red in the hyperoxia environment, and reduce to lavender myoglobin in the hypoxia environment.
Traditional vacuum-packed red meat is lavender due to lack of oxygen, which will be mistaken by consumers as not fresh and affect sales. The protective gas of modified atmosphere packaging for red meat is composed of O2 and CO2. The concentration of O2 needs to exceed 60% to maintain the red color of the meat, and the lower concentration of CO2 is not less than 25% to effectively inhibit the reproduction of bacteria.
The myoglobin content of various types of red meat is different, and the redness of the meat is different. For example, beef is darker than pork. Therefore, the concentration of oxygen in modified atmosphere packaging of different red meats needs to be adjusted to achieve better color retention and preservative effects. . The composition of the protective gas for modified atmosphere packaging of beef and mutton is usually 60%-70% O2 and 40%-30% CO2, and the shelf life of 0-4 is usually 7-10 days.