How to freeze the dried food
First, it is preferable to use a dry nitrogen (or an inert gas such as carbon dioxide) to restore the drying chamber to atmospheric pressure when the freeze-dried end is due to the hygroscopicity and the easy oxidizing property of the lyophilized food. The usual practice is to use a dry, The air to restore the freeze dryer drying chamber of the atmospheric pressure, freeze-dried food after removal, should immediately dry and clean operation between the packaging seal.
Freeze-dried food should be kept in a closed container, the packaging material should be airtight, opaque, it is generally not transparent packaging materials. As the freeze-dried food is fragile, it should be used to prevent the occurrence of mechanical damage to the packaging materials, such as metal cans, glass bottles. In addition, the mechanical vibration should be prevented during transport to protect the shape of the solid material. In addition, you can use corrugated paper, corrugated plastic or foam, such as shock-absorbing materials, or add nitrogen sealed packaging to increase the seismic capacity.
The cost of metal cans is high, but if the product is to be stored for a long period of time, the metal cans should be used. Can also use glass containers, if you can make it sealed, the effect is no less than metal cans. But the glass bottle and light, so the actual production, the proposed freeze-dried food less use of glass bottles, even if the use is also used to avoid the light is not strong brown bottles.
Today's aluminum foil composite bags have been used to replace metal and glass containers for widely used in freeze-dried food packaging. From the price and weight aspects, aluminum foil composite bag is the most ideal packaging materials. Also note that a single layer of plastic film because of its high degree of permeability and high light transmittance, so that it is not suitable for the freeze-dried food packaging materials. However, due to the low price of plastic film, easy to heat sealing, aluminum foil can shield light radiation, airtight, so the aluminum foil composite bag is the ideal dry food packaging materials. Therefore, freeze-dried food because it contains fat and fat-soluble ingredients, and easy to oxidation, so no matter what kind of packaging materials, must be in the bag of air removed or filled with inert gas sealed packaging, as much as possible to reduce the bag In the oxygen content. The density of the freeze-dried food is small, if the direct packaging, the volume is relatively large, so for some shape without the requirements of the freeze-dried food, we can take the method of compression packaging to reduce its volume. The use of hydraulic technology can be compressed products to the original volume of one sixteenth, while high-density block products on the invasion of insects have a certain resistance. However, it should be noted that the compressed freeze-dried food although the color, nutrition unchanged, but its shape completely destroyed, and some complex
In short, freeze-dried food storage link summed up the requirements to do the following:
1) the use of dark, radiation-proof, airtight packaging materials for sealed packaging, as far as possible vacuum packaging or filled with inert gas packaging.
2) to prevent the pollution of strong oxidants, especially copper, iron pollution.
3) shockproof pressure to avoid freeze-dried products.
4) The lower the storage temperature, the better, preferably below 20 ° C.