Vacuum freeze-drying technology, domestic R&D is gradually maturing
The freeze dryer (freeze dryer) consists of a refrigeration system, a vacuum system, a heating system, and an electrical instrument control system. The main components are drying ovens, condensers, refrigeration units, vacuum pumps, heating/cooling devices, etc. Freeze-drying is referred to as lyophilization, which is a method in which a water-containing substance is first frozen into a solid state, and then the water therein is sublimated from a solid state into a gaseous state to remove water and preserve the substance. The lyophilizer originated in the 1920s vacuum freeze-drying technology after decades of ups and downs, and made great progress in the last 20 years. In the 21st century, vacuum freeze-drying technology has become more and more popular with people due to the advantages that other drying methods cannot match. In addition to its wide application in the fields of medicine, biological products, food, blood products and active substances, its application scale and field Still expanding. To this end, vacuum freeze drying is bound to become an important application technology in the 21st century.
In recent years, vacuum freeze-drying technology has developed rapidly in China, but compared with foreign countries, there is still a certain gap. This paper analyzes the development of the technology at home and abroad and several aspects that should be improved. .
The development trend of production is increasing at an annual rate of 30%
Vacuum freezing technology is referred to as freeze-drying technology. The Boiler and Pressure Vessel Inspection and Research Center of the General Administration of Quality Supervision, Inspection and Quarantine is mainly engaged in the introduction of vacuum freeze-drying process optimization research. The principle of lyophilization is to use the principle of sublimation under vacuum to make the moisture in the pre-frozen material not melt directly through the ice. The ice sublimation is removed as water vapor to obtain a technique for drying the product. Practice has shown that vacuum freeze-drying dehydration technology is a high-tech processing technology suitable for color protection, preservation, quality preservation and nutrient preservation of fruits, vegetables, meat, aquatic products and medicines.
According to statistics, the United States currently consumes 5 million tons of freeze-dried food, 1.6 million tons in Japan, and 1.5 million tons in France. The consumption of other countries is also rising year by year. Today, the production of freeze-dried food on the international market is increasing at a rate of 30% per year.
China's research on freeze-drying started late. In recent years, some research institutes have carried out process research on certain products. Northeastern University has successfully studied the ginseng freeze-drying process; Sichuan University has studied the freeze-drying process of yak meat. Nowadays, with the increasing demand for freeze-dried products by Chinese consumers, freeze-drying equipment has also developed considerably.
According to experts, since vacuum freeze-drying is carried out under low temperature and high vacuum, the moisture in the material is directly sublimated from the solid state to a gaseous state, so that the cell activity of the dried material and the color, fragrance and taste of the dried material can be kept to the utmost. , shape and nutrients, and good rehydration performance. Freeze-dried food is a high-quality green food that combines convenience, health care and naturalness with modern dehydration technology and technology. Thereby, the disadvantages of discoloration, odor, loss of components and inability to reduce by the conventional dehydration method are avoided.
The overall design and control level of the domestic status quo has improved
The quality of freeze-dried foods, in addition to the process, depends to a large extent on the food freeze-drying equipment. The food freeze dryer mainly includes a freezing library for freezing the materials, a drying chamber for sublimation dehydration, and auxiliary equipment such as vacuum, refrigeration and heating. Experts said that the world's more advanced freeze dryers mainly include: RAY-type intermittent and CON-RAD continuous freeze-drying machines from Atlas, Denmark, and the non-isolated drying process of Japan-0 Republic Vacuum Co., Ltd. De-icing regeneration technology and TL type liquid food concealed system tubular lyophilizer.
In addition, the research institute of the Institute of Cryogenic Biology and Freeze-Drying Technology, which was established in Bulgaria more than ten years ago, with research on aerospace foods, health foods and nutritious foods, is also extremely strong.
In recent years, domestic food freeze dryers have developed rapidly, with more manufacturers, and different quality, performance and specifications. In the early 1950s, a number of freeze-drying machines were imported from the Institute of Biological Products in Wuhan and Beijing. In the 1960s, some experimental freeze-dried food manufacturers were established in Beijing, Tianjin, Nanjing, Shanghai and Dalian. And have copied a batch of freeze dryers. Its characteristics are integral, the shelf temperature is not uniform, manual operation, can automatically record; in the 1970s, Hubei designed a freeze dryer, using a single-stage two-stage compressor, can be capped in the box; Shanghai A medium-scale freeze-drying workshop with an annual output of 300 tons was established.
In order to speed up the development of freeze-drying technology in China, the Ministry of Electrical and Mechanical Services listed the industrial vacuum freeze dryer into the Industrial Technology Development Fund Project of 1986. It was undertaken by Huazhong University of Science and Technology and developed in collaboration with Zhejiang Vacuum Equipment Factory. The product passed the ministerial appraisal in 1989. The machine is compact in structure, complete in function, adjustable in shelf spacing, and adopts microcomputer program control.
Vacuum freeze-drying technology has a wide range of applications in the fields of bioengineering, pharmaceutical industry, food industry, materials science and deep processing of agricultural and sideline products. Freeze drying of drugs includes two parts: western medicine and traditional Chinese medicine. Western medicine freeze-drying has been developed in China, and many larger pharmaceutical plants have freeze-drying equipment. In terms of traditional Chinese medicine, it is still limited to lyophilization of a small amount of Chinese medicinal materials such as ginseng, velvet, yam, and Cordyceps sinensis. A large number of proprietary Chinese medicines have not been freeze-dried, which is far from the foreign countries. In the field of biotechnology products, freeze-drying technology is mainly used for the production of drugs such as serum, plasma, vaccines, enzymes, antibiotics, hormones; biochemical inspection drugs, immunology and bacteriology; drugs; blood, bacteria, arteries, bones Long-term preservation of skin, cornea, nerve tissue and various organs.
So far, a number of well-made and high-performance freeze-drying machine preparation manufacturers have emerged in China, among which Shanghai Dongfulong, Beijing Bo Yikang, Qianshan Far East and other manufacturers focus on the development of freeze-drying machine manufacturing process, its production The quality performance of the freeze dryer has reached the international advanced level.
For the treatment of diseases of the respiratory system:
Diseases and conditions of the respiratory system fall into two categories: Viruses such as influenza, bacterial pneumonia and the new enterovirus respiratory virus that has been diagnosed in children; and chronic diseases, such as asthma and chronic obstructive pulmonary disease (COPD). According to Dr. Neal Chaisson, who practices pulmonary medicine at the Cleveland Clinic, there is not much that can be done for viral infections but to let them run their course. "Antibiotics are not effective in treating viruses and the best thing to do is just rest," he said.
COPD is the intersection of three related conditions - chronic bronchitis, chronic asthma and emphysema, Chaisson told Live Science. It is a progressive disease that makes it increasingly difficult for sufferers to breath.
Asthma is a chronic inflammation of the lung airways that causes coughing, wheezing, chest tightness or shortness of breath, according to Tonya Winders, president of the Allergy & Asthma Network. These signs and symptoms may be worse when a person is exposed to their triggers, which can include air pollution, tobacco smoke, factory fumes, cleaning solvents, infections, pollens, foods, cold air, exercise, chemicals and medications.
Lung cancer is often associated with smoking, but the disease can affect non-smokers as well. Every year, about 16,000 to 24,000 Americans die of lung cancer, even though they have never smoked, according to the American Cancer Society. Like all cancers, lung cancer is caused by the uncontrolled growth of abnormal cells.
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