Freeze-drying storage

Freeze-drying is a combination of these two processes. With freeze-drying, storage at low temperatures is avoided and in addition, reactions which can still happen at low temperatures if water is present - even in the form of ice - cannot occur. Freeze-drying is the careful drying of a frozen product under vacuum through sublimation of the solvent at temperatures below the freezing point of the solvent. 

Tang, Y.C. and Chen, B.H., Pigment change of freeze-dried carotenoid powder during storage, Food Chem., 69, 11, 2000. 

Karaali, A., Meydanoglu, F., and Eke, D. (1988). Studies on composition, freeze-drying and storage of Turkish royal jelly. /. Apicult. Res. 27,182-185. 

Fig. 7 Collapse is characteristic of amorphous materials, and can occur either during the freeze-dry process or during storage. 

B. Lueckel, B. Helk, D. Bodmer, and H. Leuenberger, Effect of formulation and process variables on the aggregation of freeze dried interleukin-6 (IL-6) after lyophilization and storage, Pharm. Dev. Technol., 3, 337 (1998). 

Kon M and Shimba R. 1989. Changes in carotenoid composition during preparation and storage of frozen and freeze-dried squash. Nippon Shokuhin Kogyo Gakkaishi 36 619—624. 

Fig. 1.44. Scanning electron-microscopic photographs of a vial containing freeze dried trehalose solution, (a), collapsed product from the bottom of the product (b), shrunk product after 6 months of storage at +20 °C with a RM too high and stored at a too high a temperature (Fig. 6 from [ 1.29]).

Kanaori et al. [1.122] studied the mechanism of formation, and association of human calcitonin (hCT) fibrils using NMR. hCT associates and precipitates during storage in aqueous solution. The freeze dried hCT and its behavior is described. 

The storage of a freeze dried product starts with the end of the secondary drying and its transfer into a suitable packing. In the drying plant a certain residual moisture content (RM) is achieved as a function of the product temperature and the drying time (Section 1.2.2). 

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