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About Freeze-Drying:
Freeze-drying, as compared to other drying
processes such as spray drying or air drying, is used on Dynamic
Nutraceuticals products because it is better at retaining the
characteristics of the raw food. It is well known that the process
retains more flavor components and results in reconstituted
textures that most closely approximate the un-dried material. In
effect, freeze-drying is the least damaging of the drying
processes available to food processors. It is not used more
extensively simply because it's cost is much higher than other
processes. The ability to minimize damage to food attributes and
components during drying is the reason for claims that the process
is also less damaging to enzyme activity. That is, more enzymes
will be active (still able to catalyze chemical reactions) in a
freeze-dried food than in some raw material dried in another
manner. In fact, the results are so marked that many vegetables
dried for commercial use as ingredients in dry soup mixes or army
field rations are first put through a blanching treatment to
inactivate enzymes that would survive the drying process - for
most of the food industry, extreme shelf life is much more
important than retention of nutritive properties.
Perhaps a clearer example would be to consider
that freeze-drying is the method of choice in the lab for
preserving protein activity, or even entire organisms, in a dry
sample. Freeze-drying is the only good way to get a product with a
reasonable shelf life that can still be said to be alive.
Freeze-drying's ability to better maintain the
nutritional properties of foods is documented in many studies. A
comparison of drying methods shows why: proteins can be denatured
by high temperature, oxidation, or by reactions with other cell
components, often other proteins. Freeze- drying occurs in a
oxygen-free vacuum at very low temperatures (-20F) and since the
product being dried is in a frozen state, there is little mobility
at the molecular level - and if molecules can't move, they can't
react with each other either. Spray drying or air drying, on the
other hand, is done in normal atmospheres at much higher
temperatures; and since moisture in the product is in the liquid
phase, denaturing can occur. Higher temperatures and mobility
make these reactions occur more frequently.
Dynamic Nutraceuticals goal is to produce
products that are as close as possible to their original raw,
fresh state. |