Product management

All have
Product management
News
Introduction led
Corporate store
FAQ
Enterprise Video
Enterprise map

Home page

BLOG

Focus on hot topics, real-time dynamics

Working principle of vacuum freeze dryer

2025-06-10

The basic process of freeze-drying is as follows:
a. Preparation (pre-treatment) of products: such as drug cultivation, sterilization, packaging, bottle washing, semi stoppering, etc., selection, cleaning, cutting, enzyme inactivation, packaging, etc. of food raw materials.
b. Freezing (pre freezing) of products: Freeze the products into a solid state.
c. The first stage of drying (sublimation drying): remove ice crystals from the product by sublimation.
d. Second stage drying (desorption drying): evaporate a portion of the residual moisture in the product at a higher temperature to meet the predetermined requirements.
e. Sealed packaging: Dried products should generally be sealed and packaged under vacuum or inert gas conditions to facilitate storage.
Advantages of freeze-drying:
Freeze drying has the following outstanding advantages compared with common drying, boiling drying, spray drying and vacuum drying.
a. Freeze drying is the process of 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 biologically active products, biochemical products, genetic engineering products, and blood products with poor thermal stability.
b. During the low-temperature drying process, the growth of microorganisms and the action of enzymes are almost impossible to carry out, which can best maintain the original properties of the substance.
c. After drying, the volume and shape remain basically unchanged, and the substance is sponge like without drying shrinkage. When rehydrated, it has a large contact surface with water and can quickly return to its original shape.
d. Because it is usually dried under vacuum, there is very little oxygen gas, which protects easily oxidizable substances.
e. It can remove 95% to 99.5% of the moisture in the substance, and the product has a long shelf life.