The key point of food MAP fresh-keeping packaging -2
The relationship between packaging materials and the shelf life of modified atmosphere packaging
In order to maintain the given concentration of the mixed gas in the package, the packaging materials of modified atmosphere packaging for food (excluding fresh fruits and vegetables) have the following requirements:
(1) Mechanical strength of packaging materials
The packaging material has a certain resistance to tearing and puncturing, especially for packaging fresh fish and bone-in meat.
(2) Gas barrier properties of packaging materials
Because the permeability of most plastic packaging materials CO2 gas is 3 to 5 times greater than that of O2, food modified atmosphere packaging requires the use of multi-layer plastic composite packaging materials with high gas barrier properties. High barrier PVDC and EVOH are the best barrier layers for plastic composite packaging materials.
(3) Water vapor barrier properties of packaging materials
In order to avoid weight loss of packaging products due to water loss, packaging materials for modified atmosphere packaging of foods require a certain water vapor barrier properties. The recommended moisture permeability is 0.1g / (m2. 24h. ℃) packaging materials.
(4) Anti-fog properties of packaging materials
Most modified atmosphere packaged foods require refrigerated storage or sale. The temperature difference between the inside and outside of the package makes the moisture produce droplets in the packaging film and affect the appearance of the product. The anti-fog plastic packaging material is adopted so that the moisture in the packaging does not form fog droplets.
(5) Heat-sealability of packaging materials
In order to maintain the mixed gas in the packaging, the seal of the packaging bag or box has a certain strength and is completely sealed without slight leakage. The heat sealability of polyethylene is the most reliable.
