Drying is one of the ways to insist that matter will not decay.  There are many drying methods, such as air drying, boiling, drying, spray drying and vacuum drying.  However, these drying methods are all carried out at temperatures above 0.degree. C. or higher.  The dried products are generally reduced in volume and hardened in texture. Some substances are oxidized, some volatile components are mostly lost, and some thermosensitive substances, such as proteins and vitamins, are denatured.  Microorganisms will lose their biological activity, and dried substances are not easy to dissolve in water.  Therefore, the dried products are quite different from those before drying in character.  However, the freeze-drying method using a Freeze Dried Fruit Machine is different from the above-mentioned drying method. The drying of the product is basically carried out at a temperature below 0℃, i.e. in the frozen state of the product. Until the later stage, in order to further reduce the residual moisture content of the product, the product is only allowed to rise to a temperature above 0℃, but generally does not exceed 40℃.

Freeze-drying of Lyophilization Equipment is to freeze the substance containing a lot of moisture into a solid by lowering the temperature in advance, and then make the water vapor directly travel out under the condition of vacuum, while the substance itself remains in the ice shelf when frozen, so its volume will not change after drying, and the porous material will absorb heat when traveling.  It is necessary to properly heat the product in order to increase the traveling speed and shorten the drying time, which will cause the temperature of the product itself to drop and slow down the traveling speed.  The whole drying is carried out at a lower temperature.