Foods are dehydrated to make them more easily packaged and stored at room temperature. The removal of water reduces the opportunity for harmful chemical reactions. Dehydrated food powders and particles are also used in "liquid meals" for dental patients. However, dehydrated foods traditionally have been difficult to rehydrate and are of relatively poor quality. The reasons for these difficulties are from thermal damage due to the high temperatures necessary to dehydrate the foods. A process useful for heat sensitive foods, which is presently being used ty the U.S. Army for their dehydration needs, is freeze drying. Freeze drying, although effective, has its drawbacks. Freeze drying is a very expensive process involving high capital costs and high energy cost. S.R. Taylor and Associates proposes an alternative method to do dehydration for the U.S. Army. Ultrasonic drying has been proven effective for certain types of heat-sensitive materials, such as many fresh foods. Phase I will determine which food-types would be appropriately dried ultrasonically, and at which processing variables. Phase II would involve process optimization for the highest quality dried rehydrated product at the lowest cost. S.R. Taylor and Associates has actively been involved in developing a novel ultrasonic flexural plate design to deliver a highly axisymmetric sound beam into gaseous and liquid media. This unique flexural plate will produce the desired sound wave pattern to enhance food dehydration at unharmful temperatures and conditions.
