Frozen food packaging bags belong to special purpose container, in order to improve the freshness and shelf life of products, you need to use frozen or refrigerated, drastically restrict the growth of microorganisms, reduce the deterioration rate of food.
And according to the types of food we performance requirements for product packaging and storage temperature differences, too.
At the same time we when storing food and nutrition and taste of food into consideration.
Different products are a suitable storage temperature, such as 1.
Tea at 20 degrees below zero to 10 degrees temperature storage, can prevent quality become worse for a long time, to keep the vitamins are not destroyed.
- the best temperature: grains is 8 degrees
15 degrees, can prevent the grain insects.
The best temperature of frozen fish: is the following 3 degrees below zero, fish non-perishable under this temperature, insurable its taste.
In addition to frozen food there will be two problems: 1.
Dry and freeze burn in consumption caused by air pressure will change with the temperature of cold food water vapor form difference and empty in the freezer, the sublimation of ice crystal and the decrease of the surface, quality.
This is a dry loss phenomenon.
Frozen meat during storage in nature a kind of special form according to freeze burn.
It is characterized by the entire surface of the frozen meat dry or dry spots.
Burn is a frozen food frozen during the frozen fat oxidative rancidity and carbonyl ammonia reaction as a result, it not only makes the food produce clams, and tan change, sensory, flavor and nutritional value.
Packaging materials in the frozen environment performance gradually decline is the main material of frozen food packaging plastic, plastic for a long time in a brittle fracture in low temperature environment, physical performance fell sharply, reflecting the weakness of plastic material cold resistance is poorer.
Generally, plastic cold resistant performance using brittle temperature said.
With the decreasing of temperature, the plastic because of its lower polymer molecular chain activity and thus become brittle easy to fold, under the impact strength of regulations, 50% of the plastic brittle failure occurs, the temperature is the brittle temperature, the normal use of plastic materials temperature limit.
If frozen food packaging material cold resistance is poorer, later in the process of transportation loading and unloading, frozen food packaging sharp bumps very easy to Pierce, leakage problem, accelerate the corruption of the food.
The solution as the greatest degree to reduce the frequency of the above two problems, ensure the safety of frozen food, can from the following several aspects.
1, choose high separation, high intensity of inner packaging materials packaging materials of different variety, performance, only understand a variety of physical properties of packaging materials, can according to the frozen food protection asked to choose a reasonable material, make it can not only maintain the food flavor and quality, also to manifest the value of goods.
At present, the frozen food used in the field of plastic flexible packaging important is divided into three categories: the first is single bags, such as the PE bag, its barrier effect is quite poor, widely used for packing vegetables, etc. ;
The second category as compound RuanSu bags, it adopts the double layer or multilayer adhesive plastic film material together, such as OPP/LLDPE, NY/LLDPE, moistureproof, cold resistant, durable thorn performance is quite good;
Third class as multilayer co-extrusion RuanSu bags, its functions of the different materials such as PA, PE, PP, PET, EVOH, etc. , in turn, melt extrusion, blow molding, cooling composite together, this kind of material do not use adhesive, has no pollution, high separation, high intensity, high and low temperature resistance and other characteristics.