Views: 201 Author: Wendy Publish Time: 2023-05-15 Origin: Site
Vacuum freeze-drying is the method of freezing a water-containing substance to a solid state, and then subliming the water therein from a solid state to a gaseous state to thereby remove water and preserve the substance.
Compared with the usual drying, boiling drying, spray drying and vacuum drying, freeze-drying has the following outstanding advantages.
a.Lyophilization is dry at low temperatures, does not denature protein, but can make microorganisms lose their biological activity. This is especially useful for the dry storage of bioactive, biochemical, genetically engineered, and blood products that have poor thermal stability.
b.During low-temperature drying, the growth of microorganisms and the enzyme’s action are almost impossible to process, thereby maintain the original properties of the material.
c.After drying, the volume and shape are basically the same, the material is sponge-like, no shrinkage, and the contact surface with water after rehydration is large, and can quickly return to the original shape.
d.Due to the fact that it is usually dried under vacuum, there is very little oxygen and the easily oxidized substances are protected.e.Can remove 95% to 99.5% of water in the substance ,the finished product has long shelf life.
Freeze-drying technology is more and more popular because of the unparalleled advantages compared with other drying methods. It has been widely used in various fields such as medicine, biological products, foodstuffs and active substances. Its application scale is still rapidly expanding. Vacuum freeze drying is bound to become an important application technology in twenty-first Century.
a. live bacteria vaccine. For example, BCG, meningococcal vaccine, tuberculosis vaccine, oral live dysentery vaccine, Salmonella, Streptococcus and so on.b. fire poison vaccine. Such as measles vaccine, flu vaccine, rabies vaccine, chicken plague vaccine.c. other biological products, biochemical drugs. Hepatitis B surface antigen diagnosis snowball, human leukocyte interferon, coenzyme A (CoA), adenosine triphosphate (ATP), urokinase and so on.
Mostly are for injection, with antibiotic drugs, circulatory organ drugs, central nervous drugs, vitamins and oncology drugs for more. For example, ampicillin, bacilli (erythromycin ethylsuccinate tablets) and so on.
In recent years, with the lyophilized method of processing proprietary Chinese medicines, prepared good proprietary Chinese medicines, after dipping, extraction, filtration, concentration, freeze-dried and then made in to powder , tablets, or injection.
Using freeze-drying technology can be long-term preservation of blood, arteries, bones, skin, cornea and nerve tissue and other organs. When the cells are lyophilized, the cells are not destroyed, and the organisms can revive after rehydration. For example, freeze-dried bones can be stored at room temperature or in a refrigerator for up to 2 years.
a.cooking ingredients: meat, eggs, fish, vegetables and so on.
b. Raw materials for the food industry: milk powder, egg powder, vegetable protein powder, tea, dried fruit, meat meal, soybean meal and the like.
c. Beverages: coffee, fruit drink and so on.
d. Tonic categories: pollen, honey powder, turtle powder and so on.
a. Microbial and algae aspects: Long-term preservation of various bacteria, yeasts, enzymes, protozoa, microalgae, etc.
b. Biological specimens, biological tissue: such as making a variety of animal and plant specimens, dry preservation for animal xenotransplantation of the skin, bones, aorta, heart valves and other marginal tissues.
c. Make small pieces of tissue for use in light microscopy, electron scanning and transmission microscopy.
d. Drying of food: such as coffee, tea, meat and fish eggs, seaweed, fruits, vegetables, spices, tofu, instant food and so on.
e. Advanced nutrition and Chinese herbal medicine: such as royal jelly, honey, pollen, herbal preparations.
f. Preparation of ultrafine powder: Preparation such as Al2O3, ZrO2, TiO2, Ba2Cu3O7 ~ 8, Ba2Ti9O20 and other ultrafine powder.
g. In other aspects, such as the catalyst in chemical industry, the catalytic efficiency can be increased by 5 to 20 times after lyophilization; the leaves and the soil are lyophilized and preserved for studying the influence of soil, fertilizer and climate on plant growth and the role of factors; Damp wooden artifacts, submerged book articles, etc. are dried by freeze drying method.