Drying Vegetables

Quick Facts...

• Successful drying depends on heat, air dryness and air circulation.
• Select vegetables to be dried at peak flavor and quality.
• Blanch vegetables before drying to stop enzyme action and enhance destruction of microorganisms.
• Package dried foods in tightly sealed containers and store in a cool, dry place.

Drying is one of the oldest methods of food preservation. Drying preserves foods by removing enough moisture from food to prevent decay and spoilage. Water content of properly dried food varies from 5 to 25 percent depending on the food. Successful drying depends on:

• enough heat to draw out moisture, without cooking the food;
• dry air to absorb the released moisture; and
• adequate air circulation to carry off the moisture.

When drying foods, the key is to remove moisture as quickly as possible at a temperature that does not seriously affect the flavor, texture and color of the food. If the temperature is too low in the beginning, microorganisms may survive and even grow before the food is adequately dried. If the temperature is too high and the humidity too low, the food may harden on the surface. This makes it more difficult for moisture to escape and the food does not dry properly.

Although drying is a relatively simple method of food preservation, the procedure is not exact. A “trial and error” approach often is needed to decide which techniques work best.

Nutritional Value of Dried Foods

Drying, like all methods of preservation, can result in loss of some nutrients. Nutritional changes that occur during drying include:

• Calorie content: does not change, but is concentrated into a smaller mass as moisture is removed.
• Fiber: no change.
• Vitamin A: fairly well retained under controlled heat methods.
• Vitamin C: mostly destroyed during blanching and drying of vegetables.
• Thiamin, riboflavin, niacin: some loss during blanching but fairly good retention if the water used to rehydrate also is consumed.
• Minerals: some may be lost during rehydration if soaking water is not used. Iron is not destroyed by drying.

For best retention of nutrients in dried foods, store in a cool, dark, dry place and use within a year.

more details here...
http://www.ext.colostate.edu/pubs/foodnut/09308.html