Is Freeze-Drying Just Dehydrating?

The terms: Freeze-drying and dehydration can be easily mistaken for the same food preservation methods. But they GREATLY differ in terms of the benefits and method used to preserve food. For example:

-Freeze-drying: Freeze-drying, also known as lyophilization, involves freezing the food at extremely low temperatures and then subjecting it to a vacuum environment. In this process, the frozen water in the food sublimates directly from ice to vapor without passing through the liquid phase. In simple terms, the water in the food turns from a solid to a gas, skipping the liquid state of water. This results in a final product that retains much of its original shape, texture, flavor, and nutritional content. Freeze-dried foods typically have a porous structure and can be quickly rehydrated when exposed to moisture. This is due to water not having a chance to melt and turn the food into mush, instead as the food dehydrates, almost all of the water content in the food is removed. 

-Dehydration: Dehydration, on the other hand, involves removing moisture from food by applying heat, circulating air, or both. This process can be done through various methods such as sun-drying, oven-drying, or using food dehydrators. Dehydration typically results in a shriveled or leathery texture, and the food may lose some of its flavor, color, and nutritional content due to exposure to heat.  However, dehydrated foods still retain many of their nutrients and can have a long shelf life when stored properly.