Is it necessary to pretreat foods before drying them?
Pretreatment is not necessary for successful food drying, but it can enhance the color, flavor, and texture of certain foods and restore vitamin C to fruit that may otherwise be reduced in the dehydrating process. Pretreatment methods include dipping and or sulfuring fruit, blanching vegetables and marinating meats. Fruit dipping is a pretreatment used to prevent fruits from turning brown and to add vitamin C to fruit. Ascorbic acid and fruit juices high in vitamin C (for example lemon, orange and pineapple) may be used for dipping. Sodium sulfite is a water soluble compound of sodium and can be used as a dipping preservative to prevent dried fruit from discoloring or browning. Blanching is briefly precooking vegetables in boiling water or steam and it is used to shorten food drying time and kill organisms that could cause spoilage. Steaming is the preferred method as it is not nearly as damaging to the vegetables from a nutritional loss standpoint. Prior to dehydrating meat, the Unite
Pretreatment is not necessary for successful drying, but it can enhance the color, flavor, and texture of certain foods. Pretreatment options include dipping, blanching, marinating, and sulfuring. Pretreatment affects the enzymes, a group of special proteins that cause chemical reactions-ripening and eventual spoilage-and determine the color, texture, flavor, and aroma of certain foods. The microorganisms that cause spoilage need moisture to live and reproduce. Drying foods above 140°F halts enzyme activity. Foods also contain simple yeasts, molds, and bacteria, all of which can cause deterioration. Again, reducing the moisture content of food inhibits their growth. When dried, vegetables contain only about 3 percent moisture, and fruits, depending upon sugar content, up to 15 percent water. For an in-depth discussion of pretreatment methods for fruits and vegetables, see pages 33-37.
