(Content provided by: The Ohio State University Extension Human Nutrition)

Drying is the oldest method of preserving food. Through- out history, the sun, the wind, and a smokey fire were used to remove water from fruits, meats, grains, and herbs.

By definition, food dehydration is the process of removing water from food by circulating hot air through it, which prohibits the growth of enzymes and bacteria.

Dried foods are tasty, nutritious, lightweight, easy-to-prepare, and easy-to-store and use. The energy input is less than what is needed to freeze or can, and the storage space is minimal compared with that needed for canning jars and freezer containers.

The nutritional value of food is only minimally affected by drying. Vitamin A is retained during drying; however, because vitamin A is light sensitive, food containing it should be stored in dark places. Yellow and dark green vegetables, such as peppers, carrots, winter squash, and sweet potatoes, have high vitamin A content. Vitamin C is destroyed by exposure to heat, although pretreating foods with lemon, orange, or pineapple juice increases vitamin C content.

Dried foods are high in fiber and carbohydrates and low in fat, making them healthy food choices. Dried foods that are not completely dried are susceptible to mold.

Microorganisms are effectively killed when the internal temperature of food reaches 145 degrees Fahrenheit (F).

To be certain of the final quality and consistent drying of foods, a dehydrator is recommended. Sharp knives and a food processor or blender will also make the drying task easier.

Many guidelines call for blanching, steaming, or pre-treating foods. Equipment for these processes include a deep kettle with a lid and a wire basket, a colander, or an open mesh cloth bag to hold produce. A non-metal bowl is best for pretreating fruits and vegetables to prevent discoloring.

Select ripe fruit for drying. Bruised fruit can be used if you trim away any bruised spots. Do not use molding food for drying.

Slicing foods allows the dry air to circulate and dry the surface area of the food first. Cut foods into 1/8-inch to 1/2-inch slices. The higher the water content, the larger you should make the slice size. Small slices of high-moisture foods, such as watermelon, would disappear when all the moisture has evaporated.

Peel fruits and vegetables, including bananas, melons, winter squash, and other foods.

Pre-treatments are techniques used to make quality products. Pre-treatments include dipping, blanching, cooking, or candying.

Dipping prevents oxidation or color changes in fruits and vegetables. Dip fruits in pineapple or orange juice. Dip vegetables in diluted bottled lemon juice (dilute 1/4 cup of lemon juice in 2 cups water, then dip vegetables and some fruits for 2 to 3 minutes).

Commercial fresh fruit stabilizers can also be used (dilute 1/2 Tablespoon of stabilizer in 2 cups water). Sodium sulfite is another commercial product for pre-treating foods. To make a homemade stabilizer, mix 1 Tablespoon of salt or vinegar with 8 cups of water or dissolve one 500 mg tablet of vitamin C per 1 cup of water.

Blanching is recommended for asparagus, green beans, broccoli, Brussels sprouts, cauliflower, and peas. Blanch for a very short period to cause checking of skins.

If you choose to sweeten the leather, add corn syrup, honey, or sugar. Corn syrup or honey is best for longer storage because they do not crystallize. Sugar is fine for immediate use or short storage. Use 1 1/4 to 1 1/2 cups sugar, corn syrup, or honey for each 2 cups of fruit. Saccharin-based sweeteners could also be used to reduce tartness without adding calories. Aspartame sweeteners may lose sweetness during drying.

Home-preserved or store-bought canned or frozen fruit may also be used to make leathers. Drain fruit and save liquid. Use 1 pint of fruit for each 13-inch by 15-inch leather. Purse fruit until smooth--if too thick, add liquid. Add 2 teaspoons of lemon juice or 1/8 teaspoon ascorbic acid (375 mg.) for each 2 cups of light-colored fruit to prevent darkening. Applesauce can be dried alone or added to any fresh fruit purse as an extender. It decreases tartness and makes the leather smoother and more pliable.

For drying in the oven, a 13-inch by 15-inch cookie pan with edges works well. Line pan with plastic wrap, being careful to smooth out wrinkles. Do not use waxed paper or aluminum foil.

To dry in a dehydrator, purchase specially designed plastic sheets or line plastic trays with plastic wrap.

Fruit leathers can be poured into a single large sheet (13-inch by 15-inch) or into several smaller sizes pieces. Spread puree evenly, about 1/8-inch thick, onto drying tray. Avoid pouring purse too close to the edge of the cookie sheet. The larger fruit leathers take longer to dry. Approximate drying times are 6 to 8 hours in a dehydrator, up to 18 hours in an oven, and 1 to 2 days in the sun.

Dry fruit leathers at l40 degrees F. Leather dries from the outside edge toward the center. Test for dryness by touching center of leather; no indention should be evident. While warm, peel leather from plastic and roll. Then, allow the leather to cool and rewrap the roll in plastic.

Chances are the fruit leather won't last long enough for storage. If it does, it will keep up to 1 month at room temperature. For storage up to 1 year, place tightly wrapped rolls in the freezer.

(Content provided by: University of Illinois at Urbana-Champaign College of Agriculture Cooperative Extension Service)

Many kinds of fresh fruits, vegetables, herbs, meat, and fish can be dried. If you have never tried drying food before, though, it's a good idea to experiment first by drying a small quantity in the oven. This way you can see if you like the taste and texture of dried food. At the same time, you can become familiar with the drying process.

Fruits are easier to dry than vegetables because moisture evaporates wore easily, and not as much moisture must be removed for the product to keep. Ripe apples, berries, cherries, peaches, apricots, and pears are practical to dry.

Vegetables that are also practical to dry include peas, corn, peppers, zucchini, okra, onions, and green beans. Produce from the supermarket is usually more expensive and not as fresh as it should be for drying. It is a waste of time and energy to dry vegetables such as carrots that can be kept for several months in a cool, dry basement or cellar.

Fresh herbs of all types are suitable for drying. The parts of the plant to dry vary, but leaves, seeds, or blossoms usually give the best results.

Lean meats such as beef, lamb, and venison can be dried for jerky. Fish also is excellent when dried. Certain foods are not suitable for drying because of their high moisture content. Lettuce, melons, and cucumbers are a few foods that do not dry well.

Don't be surprised to find a variety of suggestions for drying methods, temperatures, and lengths of time. The drying process is simply not as precise as canning and freezing because it involves so many different factors. You may need to use a trial-and-error approach to find what suits you best. Whatever method you use, be sure to remove enough moisture from the final product so that spoilage organisms cannot grow.

• Cleanliness and sanitation are essential.

• The flavor of dried fruits and vegetables will be somewhat different from that of their fresh, canned, or frozen counterparts.