The Technology
Freeze
drying is the process of dehydrating frozen foods under a vacuum so
the moisture content changes directly from a solid to a gaseous form
without having to undergo the intermediate liquid state through
sublimation. In this process, the product maintains its original size
and shape with a minimum of cell rupture. Removing moisture prevents a
product from deteriorating at room temperature.
The process is used for drying and preserving a number of food
products, including meats, vegetables, fruits, and instant coffee
products.
The dried product will be the same size and shape as the
original frozen material and will be found to have excellent stability
and convenient reconstitution when placed in water. Freeze dried
products will maintain nutrients, color, flavor, and texture often
indistinguishable from the original product.
Depending on the product and the packaging environment, freeze
dried foods are shelf-stable at room temperature for up to twenty-five
years or more, if canned or sealed in a zero gas transmission rate container, and between 3 to 10 years if stored in
a quality poly-foil bag container in a proper environment.
The main determinant of degradation is the amount and type of
fat content and the degree to which oxygen is kept away from the
product.
