When choosing packaging materials for frozen food packaging bags, first of all, the sensitive factors affecting the main components of frozen food, especially the nutrients such as fat, protein and vitamin, including light, oxygen, temperature, microorganism and physical and mechanical factors should be studied.Then, according to the protective requirements of the contents, the transportation environment, etc., determine the type of the frozen food packaging bags and the operation method of the packaging technology, so as to achieve the protection function and extend storage period appropriately.
From the perspective of safety, packaging materials directly in contact with food, such as plastic bags, must reach food grade.Because of the packaging and transportation process of frozen food, it is often difficult to guarantee that the whole journey is in a consistent low-temperature environment. Especially in the process of transfer and transportation, it is very likely that the temperature of frozen food will rise significantly over a period of time.The packaging made of recycled materials or industrial materials does not differ much from the packaging made of food materials in appearance, but because of containing excessive plasticizer and other substances, once used, it will cause great harm to human health.
2. Cold resistance
Frozen food are usually at 18 ℃ or lower temperature storage and circulation, especially the part with frozen food tray, usually put food in the process of production, together with the tray at - 30 ℃ under the condition of rapid cooling, until the product center temperature below 18 ℃, and then for packaging.In the case of sudden temperature drop, the mechanical strength of the packaging materials will also decline, resulting in fragile packaging materials.In addition, in the process of transfer and transportation, frozen food will inevitably be subjected to impact, vibration, pressure and other environmental hazards.In addition, frozen foods such as dumplings and dumplings are hard at low temperatures.Easy to cause packaging bags cracking and cracking.This requires a good low temperature performance of the packaging material.
3. Impact resistance
Frozen food is easily damaged by external forces in the process of transportation, loading and unloading, and shelf placement. When the packing bag has poor impact resistance, it is easy to break the bag or open the bag.The impact resistance of frozen food packages can be measured by the pendulum impact test.
4. Heat seal strength
If the heat seal strength of frozen food package is not enough or is not enough, slight impact can cause the seal to crack.If the heat seal temperature is too high, it will easily cause damage to the heat seal layer and weaken the material strength at the sealing line. Once it is subjected to strong vibration or impact, it will easily cause the phenomenon of broken bags and large area of rotten bags, which cannot effectively protect the inner food.
5. Tensile force and interlaminar peel strength
If the peeling strength between layers of frozen food bags is small and the pulling force is not enough, the mechanical properties of the packaging bags are poor, which will easily cause the lamination of the packaging bags and fail to achieve the due load-bearing function, resulting in the protective performance of the packaging bags, and greatly shorten the shelf life of the inside food.
6. Puncture resistance
Frozen food is generally hard after being frozen, especially fish and meat products, which contain bones and hard objects. After being squeezed in the process of transportation and stacking, the product can easily break through the packaging bag and damage the sealing of the frozen food bag. Therefore, the frozen food has high requirements on the puncture resistance of the packaging bag.
7. Pressure resistance
In the process of transportation and handling, shock, drop or impact may cause damage to the transportation packaging and even the internal sales packaging. Therefore, relevant vibration or drop tests should be carried out on the frozen food packaging.Finally, choose packaging materials that can not only protect the quality of frozen food, but also reflect its commodity value and make comprehensive packaging cost reasonable.