Frozen freezing effects

Native, multi-subunit KLH also should not be frozen. Freeze-thaw effects cause extensive denaturation and result in considerable amounts of insoluble material. Commercial preparations of native KLH are typically freeze-dried solids that no longer fully dissolve in aqueous buffers and do not display the protein s typical blue color due to loss of chelated copper. The partial denatured state of these products often makes conjugation reactions difficult. 

The next stage in the zone-refining process is to move the furnace slowly and steadily to the right. The left-hand end of the bar will then cool and refreeze but with the equilibrium composition /cCq (Fig. 4.4c). As the furnace continues to move to the right the freezing solid, because it contains much less impurity than the liquid, rejects the surplus impurity into the liquid zone. This has the effect of inereasing the impurity concentration in the zone, which in turn then increases the impurity concentration in the next layer of freshly frozen solid, and so on (Fig. 4.4d). Eventually the concentrations ramp themselves up to the situation shown in Fig. 4.4(e). Flere, the solid ahead of the zone has exactly the same composition as the newly frozen solid behind the zone. This means that we have a steady state where as much impurity is removed from the... 

Butot, S., Putallaz, T., and Sanchez, G. (2008). Effects of sanitation, freezing and frozen storage on enteric viruses in berries and herbs. Int.. Food Microbiol. 126,30-35. 

Oszmianski J, Wojdylo A and Kolniak J. 2009. Effect of 1-ascorbic acid, sugar, pectin and freeze-thaw treatment on polyphenol content of frozen strawberries. LWT-Food Sci Technol.42(2) 581-586. 

Degobbis [60] studied the storage of seawater samples for ammonia determination. The effects of freezing, filtration, addition of preservatives, and type of container on the concentration of ammonium ions in samples stored for up to a few weeks were investigated. Both rapid and slow freezing were equally effective in stabilising ammonium ion concentration, and the addition of phenol as a preservative was effective in stabilising non-frozen samples for up to two weeks. 

De Antoni et al. [1.23] demonstrated, that the addition of trehalose during freezing and thawing of two strains of Lactobacillus bulgaricus improved the survival rate differentially, but in both cases considerably. The samples (1 mL) were frozen at 18 °C/min to -60 °C and thawed to 37 °C at 15 °C/min. The solution consisted of distilled water, culture medium and 10 % milk with or without trehalose. It was shown, that after three freezingthawing cycles, milk alone resulted in a survival rate of 24 % or 65 %, while with trehalose this was can be improved to 32 % and 100 % respectively. The efficacy in the case of both strains was clearly different. De Antoni et al. suggested, that the efficiency of milk was related to its Ca2+ content, while the trehalose could replace water molecules in the phospholipids of the membranes. However no mention was made wether other sugar molecules in milk showed any effect. 

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