Lyophilization or freeze drying is a process by which very different biological materials may be preserved undamaged for extended periods. Freeze-dried products may be kept at room temperature, with low weight, and their properties are restored after rehydration. In this process, the material is frozen and then the ice is removed by sublimation.
INVAP has developed lyophilization equipment with advanced technology for easier operation and maintenance.
Lyophilization is widely used to preserve a vast range of products. The process arrests the growth of microorganisms and inhibits flavor and color deterioration due to chemical reactions and loss of physiological properties. Furthermore, it allows for easier storage and distribution of different kind of products.
Nowadays, such diverse products as soup, coffee, raspberries and strawberries are freeze-dried. In this way, the cold chain is avoided, and products retain their original volume and shape despite the loss of weight.
The technique is also used to preserve blood plasma, serum, hormone solutions and biologically complex pharmaceutical products such as vaccines, serums and antidotes.
Validation system
INVAP offers verification and validation services to determine lyophilization parameters of any product that may be subjected to this process.
INVAP uses its own facilities and equipments to reproduce all the processes of industrial lyophilization. This pilot plant allows to adjust and improve operating protocols, in order adequate the design of each plant and optimize the production for our clients.
Usual procedures
INVAP provides customized turnkey plants that include all due stages: from the previous tests to determine the parameters of the process required for each product, to basic engineering, validation, construction, start up and operation.
Industrial plants designed for food lyophilization use a series of supersonic ejectors, a starting ejector and two barometric condensers. Vacuum is maintained by means of a tall liquid column, so the structure reaches a considerable height.
Food processing depends largely on the kind of product but it usually follows a series of stages. First, food is adequately prepared. Then, if necessary, the product is pre-frozen and stored in special freeze-drying chambers until it is ready for lyophilization.
The process of lyophilization itself, the product to be treated is placed in a chamber in which vacuum is rapidly produced. Next, still under vacuum, the product is heated according to pre-defined protocols.
Once this process is completed, the products are hermetically sealed and packed. If necessary, this is done under a nitrogen atmosphere. The product is now ready for distribution and marketing. The whole process varies according to design parameters, depending on the product to lyophilize and the operating shifts.
Among the facilities built by INVAP, we may mention the one installed in Gaiman, Province of Chubut, Argentina, which started operating in 1999 and the one in Querétaro, México, inaugurated in 2004.
Advantages of our plants
Lyophilization plants designed and built by INVAP require less specialized staff because they are easier to operate than traditional facilities.
For lyophilization, the product to be treated is placed in a chamber in which vacuum is rapidly produced. As pressure in the chamber drops, temperature also drops and the water contained in the product freezes. Next, still under vacuum, the product is heated and ice sublimation occurs (water turns into vapor without passing through the liquid phase).
Conventional industrial installations produce vacuum by means of a combination of vacuum pumps and cold traps which operate at -40 or -50 °C, to freeze water to be extracted from the product and to reduce the pressure within the freeze-drying chamber. The large mechanical vacuum pumps and freezing equipment require specialized labor to run and maintain - which increases cost. In INVAP freeze-drying plants, vacuum is produced by means of vapor ejectors, a technological innovation which simplifies the process and cuts operating costs.
Ejectors produce vacuum by a passive process, and need only vapor to work. They require little maintenance and are very easy to operate, which comes to bear on a decision regarding the location the installation. The system requires only gas, electricity and water to operate.
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