There are many methods of drying, such as sun drying, boiling, spray drying and vacuum drying, etc., but common drying methods are usually carried out at temperatures above 0 ° C. Dried products often have problems with reduced volume and hardened texture. Most volatile components will be lost. Some heat-sensitive substances will become denatured and inactivated, and some substances will even oxidize. Therefore, compared with the product before drying, the characteristics of the product after drying are very different. The freeze-drying method is basically performed below 0 ° C, that is, the product is frozen. It is only allowed to raise the product to a temperature above 0 ° C when the residual moisture of the product is reduced in the later period, but usually does not exceed 40 ° C. Under vacuum, when water vapor directly sublimates, it forms a sponge-like loose porous structure, so its volume is almost unchanged after drying. Before adding it again, just add water and it will dissolve immediately.
Compared with conventional methods, Lyophilization Equipment has the following advantages:
* Many heat-sensitive substances will not be denatured or inactivated.
* When drying at low temperature, there is little loss of some volatile components in the material.
* During the freeze-drying process, microorganisms and enzymes cannot grow, so the original characteristics can be maintained.
* Because it is dried in a frozen state, there is almost no change in volume, the original structure is maintained, and concentration does not occur.
* Since the water in the material exists in the form of ice crystals after pre-freezing, the dissolved inorganic salt initially dissolved in the water is evenly distributed in the material. During the sublimation process, the dissolved substances dissolved in water will precipitate out, avoiding the surface hardening caused by the precipitation of inorganic salts carried by the internal moisture of the material to the surface in the general drying method.
* The dried material is loose and porous, showing a sponge shape. After adding water, it dissolves quickly and completely, and the original performance is restored almost immediately.
* Because the drying is carried out under vacuum, there is little oxygen, so it can protect some easily oxidized substances.
* Drying can exclude more than 95% to 99% of moisture, so the dried product can be stored for a long time without deterioration.
Disadvantages of Freeze Dried Fruit Machine
As there is no seamless technology, the main disadvantage of vacuum freeze-drying technology is high cost. Due to the need for vacuum and low temperature conditions, the freeze-dried fruit machine needs to be equipped with a vacuum system and low temperature system, so the investment cost and operation cost are relatively high.