Cooperative Extension Service) University of Utah
Drying of Food at HomePreserving 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
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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.