Principles and Application Fields of Freeze-drying Machines

Principle of Vacuum Freeze Drying:

Vacuum freeze-drying is a method of freezing water containing substances into a solid state, then sublimating the water from the solid state to a gaseous state, thereby removing the water and preserving the substance.

1. Advantages of freeze-drying:

Freeze drying has the following outstanding advantages compared with common sun drying, boiling drying, spray drying and vacuum drying:

a. Freeze drying is drying at low temperatures, which does not cause protein denaturation, but can cause microorganisms and other organisms to lose their biological vitality. This is particularly suitable for the dry storage of bioactive products, biochemical products, genetic engineering products, and blood products with poor thermal stability.

c. During the low-temperature drying process, the growth of microorganisms and the action of enzymes are almost impossible to maintain the original properties of the substance.

d. After drying, the volume and shape remain basically unchanged, and the substance appears sponge like without drying shrinkage. When re-hydrating, the contact surface with water is large, and it can quickly return to its original shape.

e. Due to the fact that it is usually dried under vacuum, there is very little oxygen gas, which protects easily oxidizable substances.

f. It can remove 95% to 99.5% of the moisture in the substance, and the product has a long shelf life.

2. The usage of freeze drying of food:

a. Cooking ingredients: meat, eggs, fish, vegetables, etc.

b. Raw materials for the food industry: milk powder, egg powder, plant protein powder, tea, dried fruits, meat powder, soybean powder, etc.

3. Application of freeze-drying:

Freeze drying technology is increasingly favored by people due to its unparalleled advantages compared to other drying methods. Currently, it has been widely used in various fields such as food, medicine, biological products, active substances, etc. Its application scale is still rapidly expanding.