Full Article. Dehydration, as in food preservation, refers to the process by which various kinds of food may be preserved for long periods of time by extracting out the water, thus preventing the development of bacteria. Dehydration has been one of the oldest techniques of food preservation. It is still widely used and practiced all over the world.
Dehydration can either be mechanical or chemical. Mechanical dehydration entails using large amounts of heat under high pressure, while chemical dehydration takes place by subjecting food materials to very high temperatures, such as those found in sun-drying. Sun-drying meat is perhaps the best known example of mechanical dehydration. This is because the high temperatures required to make sun-drying a logical approach to food preservation, since dried meat will not spoil. Sun-drying foods like fish and meat also has its disadvantages, such as reduced flavor and texture.
Vacuum Dehydration. Although this is a fairly recent development, vacuum dehydration is a viable alternative to conventional drying methods. The principle behind vacuum dehydration is that water molecules are drawn into an enclosed container, where they are either vaporized or escape through a porous membrane. Food products can be placed in a vacuum chamber and exposed to high levels of moisture for long periods of time. This method of dehydration requires very low maintenance, and the finished product (usually dry meat) is indistinguishable from freshly prepared food.