Pasteurization and Lyophilization

Pasteurization and Lyophilization
Pasteurization is a process often disposable heating liquids or substances to 60 ° C for 60 minutes or at a temperature of 70-80 ° C for 30 min. Technology was opened in the mid XIX century by French microbiologist Louis Pasteur.

During this processing in the product there are killed vegetative forms of microorganisms, but the spores remain in a viable state and in the event of an enabling environment are beginning to develop rapidly. Therefore, pasteurized products are stored at low temperatures for a limited period of time. It is believed that the nutritive value of products for pasteurization is virtually unchanged.

Lyophilization is a way of drying with a soft substance, which is dried product, is frozen and then placed in a vacuum chamber. The advantages of this method of drying are that there is no impact of high temperatures on the preparation, preservation of the dispersed phase of the preparation and use of volatile solvents. The method of freeze-drying allows obtaining dry tissue, drugs, food, etc., without losing their structural integrity and biological activity. When freeze-drying, most proteins are not subjected to denaturation and can persist for a long time with moderate cooling (about 0 ° C). Lyophilized tissues and preparations for moistening recover their initial properties. The disadvantages of lyophilization include the need for careful preparation of the drug to the drying process, the creation of high vacuum to complete drying, the duration of drying and relatively high energy costs.

Lyophilization is used, if necessary prolonged storage and preservation of various products of biological origin, for dry blood plasma, dried serums and vaccines, with organ and tissue transplantation, pharmaceutical and food industries. In life-support systems of the spacecraft use lyophilization as one of the promising methods for regeneration of water from water-containing materials.



References

Freeze Dried & Dehydrated Food Explained (2009).
Freeze Drying / Lyophilization Info Online (2009).
Pasteurization (2010).

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