(Prepared
by University of Utah Cooperative Extension Service)
Drying of Food at Home
Preserving food by drying is the oldest method of food
preservation. Sun drying of fruits
and vegetables was practiced before biblical times by
Chinese, Hindus, Persians, Greeks
and Egyptians.
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Dried foods have the advantages of taking up very little space, not requiring refrigeration and providing variety to the diet. They are good for backpacking, lunches, camping, and snacks in general.
Linda's Note: Plus, you can save a ton of money on groceries if you watch the sales and buy in bulk! You can dehydrate all that extra food and store it long before it will spoil.
Drying is a comparatively simple process, requiring little outlay of equipment, time and
money. Even though drying is not difficult, it does take
time, constant attention, skill,
and understanding of the principles of food drying methods.
How Does Drying Preserve Food?
Preserving food requires the control of enzymes and
microorganisms. Microorganisms
which grow rapidly on raw or fresh food products can be
controlled by drying because
the lack of water limits the growth of microorganisms;
however, drying
does not kill the
microorganisms. Inactivation of enzymes in the fruit or vegetable is
usually controlled by a pretreatment. Enzymes can catalyze undesirable flavor
and color changes.
Nutritional Value of Dried Fruits and Vegetables
Fresh produce provides calories, fiber, minerals and
vitamins. Changes that can be
expected in home-dried food are listed below:
- Calories: No
change. The calorie content of the dried food, however, will be higher per
unit of weight because nutrients become more concentrated as water is removed.
- Fiber: No change
- Minerals: Some may
be lost in soaking, but no data are available. None is lost in the drying
process.
- Vitamins: Those
most often found in fruit and vegetables are A, C and the B vitamins.
- If vegetables
are blanched, vitamin A
activity is maintained to a high degree.
- Losses of
vitamin C vary widely depending on treatment.
- Speed in
drying and absence of sunlight are advantages in maintaining ascorbic
acid as is decreasing the air temperatures as complete dryness is approached.
- Only moderate
losses of B vitamins occur during drying.
- Because drying removes
moisture, the food shrinks and decreases in size and weight, thus
requiring less space for storage.
- When water is added to the
dried product, it returns to its original size.
- Yields of dried products
are directly related to how much water is in the original product.
- Twenty-five
pounds of apples will yield about 4 pounds of dried
apples.
- Twenty-five
pounds of onions will yield about 3 pounds of dried onions.
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