What is the difference between a freeze dryer and a dryer

What is the difference between a freeze dryer and a dryer


I believe that everyone probably knows its function, that is, freeze drying, so what is the difference between it and ordinary drying? Why do so many people choose to use freeze dryers? Let me explain their differences for you:


Ordinary drying is one of the ways to keep things from spoiling. There are many drying methods, such as drying, boiling, drying, spray drying and vacuum drying. But these drying methods are all carried out at a temperature above 0°C or higher. The products obtained by drying generally shrink in size and harden in texture, some substances are oxidized, and most of some volatile components will be lost. Microorganisms will lose biological activity, and dried substances are not easy to dissolve in water, etc.


The principle of freeze-drying is easy to understand. First put fresh fruits and vegetables into a freeze dryer at minus 50°C for freezing. After the fruits and vegetables are frozen, vacuumize the drying box. The ice in fruits and vegetables directly sublimates into water vapor and leaves the fruits and vegetables, while the volume of the “skeleton” of fruits and vegetables remains unchanged and loose and porous, and the water that can be removed by freeze-drying can reach more than 95%.


Freeze-drying technology is carried out at low temperature, such as proteins, microorganisms and the like will not denature or lose biological activity. When drying at low temperature, the loss of some volatile components in the substance is small, which is suitable for drying some chemical products, medicines and food.


During the freeze-drying process, the growth of microorganisms and the action of enzymes cannot be carried out, so the original properties can be maintained. Since it is dried in a frozen state, the volume is almost unchanged, the original structure is maintained, and no condensation occurs. Since drying is carried out under vacuum with very little oxygen, some easily oxidizable substances are protected. Drying can remove more than 95-99% of water, so that the dried product can be stored for a long time without deterioration.


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