What is Lyophilization?
Lyophilization is a process which extracts the water from foods and other products so that the foods or products remain stable and are easier to store at room temperature (ambiant air temperature). Lyophilization is carried out using a simple principle of physics called sublimation. Sublimation is the transition of a substance from the solid to the vapour state, without first passing through an intermediate liquid phase. To extract water from foods, the process of lyophilization consists of: • Freezing the food so that the water in the food become ice; • Under a vacuum, sublimating the ice directly into water vapour; • Drawing off the water vapour; • Once the ice is sublimated, the foods are freeze-dried and can be removed from the machine.
Lyophilization is a process more commonly known as freeze-drying. The word is derived from Greek, and means “made solvent-loving”. Lyophilization is a way of drying something that minimizes damage to its internal structure. Because lyophilization is a relatively complex and expensive form of drying, it is limited to those materials which are sensitive to heat and have delicate structures and substantial value. One of the only substances which cannot be preserved effectively by freeze-drying is mammalian cells, which are too fragile. The preferred method of preservation in the biotechnology industry, lyophilization is regularly used to preserve vaccines, pharmaceuticals, and other proteins. Freeze-drying is also used to preserve special food products, eliminating the need for refrigeration. Freeze-dried food is eaten by mountain climbers and astronauts. Lyophilization is used by botanists to preserve flower samples indefinitely. Because the process of freeze-drying removes most of the w
