Freeze Drying Technology

Overview of freeze drying technology

Freeze drying technology has been used for the storage and preparation of plasma, antibiotics, bacteria, and other biological products as early as during the Second World War. The freeze dried products can be revived after being added to normal saline if needed. In recent years, freeze drying technology has been applied in the fields of biological products, various foods, Chinese medicinal materials, chemical catalysts, ultra-fine materials, graphene, and concentrated liquid milling, etc. This technology maintains properties, ingredients, and organizational structure of the raw materials, and makes the freeze-dried products easily dissolved and preserved. Hawach has an affordable freeze dryer with full sizes for you to choose from.

principle-of-freeze-drying-technology

Principle of freeze drying technology

Sublimation is a physical phenomenon (see picture). Common water only has two forms: ice and steam in a certain vacuum environment, and there is no liquid water. Under this environment, water changes with the temperature only in the two forms. Using this principle, the object to be dried is frozen in advance, and then the temperature is gradually increased in a vacuum environment, and the ice in the object will gradually sublimate into water vapor to leave, and finally, the dried object that loses moisture will be obtained.

Difference between ordinary drying and freeze drying technology

In ordinary drying, water is evaporated and separated from the material in liquid form. Taking animals and plants or slurry as an example, these materials are mostly in soft form. As the internal moisture migrates outward and evaporates out, its solids will come to fill the voids left by the water molecules or close to each other, causing collapse and reunification. The solids left are reduced in size and hardened, and part of the solutes carried on the surface of the dried matter remain during the migration of water molecules outward. Wrinkles and hard shells are formed, and ordinary dried products are generally difficult to restore or dissolve in water.

Freeze drying technology is to separate water from solids in the form of ice. During the drying process, the materials have been frozen into solids. The voids left after ice sublimation will not be filled with solids, and naturally will not collapse. During the freezing process of the dried object, the conversion of water to ice is accompanied by volume expansion. The distance between the solid molecules not only does not shrink but increases, so the material left is porous and fluffy sponge-like, very crunchy, easy to restore, and dissolve in water.

Characteristics of freeze drying technology

1. The freeze-drying process is carried out in a closed low-temperature environment that is completely isolated from air dust, bacteria, and other pollution sources.
2. Properties of the raw materials unchanged (heat sensitivity, biological activity, taste, color, etc).
3. Products using this tech are porous crispy, easy to crush, and disperse.
4. Such products have great solubility in water.
5. Complete dehydration, dried products can be stored for a long time.

Applications of freeze drying technology

1. Biological products, medicines, and extracts:
2. All kinds of food.
3. All kinds of flowers, plant and animal specimens, cultural relics, porous ceramics, catalysts, styrene, ultrafine materials, etc.