Exactly what is 'freeze drying' and how does it differ from dehydrating?

Kainantu

Freeze drying = extraction of water from products such as peas and corn so as to retain the natural goodness. Dehydration = loss of fluids from a living body. Lyophilization, commonly referred to as freeze drying, is the process of removing water from a product by sublimation and desorbtion. This process is performed in lyophilization equipment which consists of a drying chamber with temperature controlled shelves, a condenser to trap water removed from the product, a cooling system to supply refrigerant to the shelves and condenser, and a vacuum system to reduce the pressure in the chamber and condenser to facilitate the drying process. http://www.virtis.com/pages/freez101.html Dehydration is a condition characterized by the excessive loss of water from the body. In most cases of dehydration, the body also loses salt. Symptoms of mild dehydration include dryness of the mucous membranes of the nose, mouth, and throat; reduced ability to sweat and urinate; and doughy skin. In severe dehydration, rapid loss of salt and water leads to fast heartbeat, low blood pressure, shock, and even death. http://worldbook.bigchalk.com/152550.htm Dehydration is the loss of water and salts from the body. http://www.rehydrate.org/dehydration Losses of only a few percent in an adult and up to 5% in infants are considered mild dehydration. http://www.healthcentral.com/mhc/top/000982.cfm Dehydration means the body does not have enough fluids to function at an optimal level. http://www.nlm.nih.gov/medlineplus/ency/article/000982.htm Sep 16 02, 9:27 AM

Creedy

Freeze-drying works by freezing the material and then reducing the surrounding pressure and adding enough heat to allow the frozen water in the material to sublime directly from the solid phase to the gas phase. http://en.wikipedia.org/wiki/Freeze_drying Dehydration is defined as an excessive loss of body fluid. It is literally the removal of water from an object http://en.wikipedia.org/wiki/Dehydration Aug 23 10, 12:16 AM