Freeze-drying mechanism

III. FREEZE-DRYING MECHANICAL HISTORY A. Shelf Freezing and Heating... 

TAPPEL A L (1956) Freeze-dried meat. 2. The mechanism of oxidative deterioration of freeze-dried beef, Food Res, 21, 195-206. 

Thermal expansion properties, which may be important in some processing situations, such as freeze-drying. The physical design of the container also influences its resistance to thermal and mechanical shock. 

V. MECHANISMS OF HEAT AND MASS TRANSFER IN FREEZE DRYING... 

On repeated freeze-drying of microgels with EUP-components an irreversible formation of an insoluble aggregate was observed [ 135]. It was supposed that this aggregation is due to radical reactions between adjacent microgel particles. The radicals are possibly formed by a mechanical rupture of chains due to stresses within the particles caused by freezing. 

Carpenter et al. [1.120] found that certain polymers (e. g. PVP) could stabilize multimeric enzymes during freezing and freeze drying by a different mechanism They cannot replace water molecules in the dried state therefore it is assumed that they inhibited the dissociation of the enzymes molecules induced by freezing and freeze drying. 

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. 

Flink, J. The retention of volatile components during freeze-drying A structurelly based mechanism. Freeze-drying and Advanced Food Technology, p. 351-372, 1975. Copyright 1975 Academic Press, Inc., New York, N. Y., USA... 

Carpenter, J. F., Kreilgaard, L., Jones, L. S., Webb, S., Randolph, T. W. Mechanisms of protein stabilization by nonionic surfactants. Freeze-Drying of Pharmaceuticals and Biologicals, presented by National Science Foundation, Industry/University Cooperative Research Center for Pharmaceutical Processing, CPPR, Brownsville, Vermont USA, 1998... 

We have employed two different protocols for the chemical fractionation of GSE obtained from MegaNatural-AZ based on the amounts needed for bioactivity-based assays. Batches of GSE (50 g) were extracted in acetone/water (7 3) under N2 with mechanical agitation for 12 h. The acetone was removed on a rotary evaporator and the aqueous phase was freeze-dried to yield 48 g of tannin crude extract (TCE). TCE was further fractionated following two different methods. 

Drying of Solids) 15—34 (Mechanisms in Drying) 17-26 (Freeze Drying)... 

Figure 27-7 Native nuclear lamina of Xenopus oocytes. Freeze-dried metal-shadowed nuclear envelope extracted with Triton X-100, revealing the nuclear lamina meshwork partially covered with arrays of nuclear pore complexes. Inset, relatively well-preserved area of the meshwork of nearly orthogonal filaments from which pore complexes have been mechanically removed. Bar, 1 pm. From Aebi et al.121...

Sharma. S.C. and E Seltzer "Development of Procedures to Minimize Mechanical Damage in Freeze Dried Meat Patties," J. Food Set., 42, 5. 1336-1343 (1977). 

---