Freeze dried foods are easily reconstituted and made ready for consumption. The process of freeze drying was invented in 1890 by a man named, Richard Altmann. His was a method to preserve animal and human tissue. It wasn’t until 1909 that Shackell invented a vacuum chamber that employed an electrical pump to operate it.
Further advancement didn’t occur until 1927 and 1934, when Tival followed by Elser invented and patented improved freeze-drying systems that included condensing and freezing. These processes came in handy when World War II soldiers needed access to penicillin and blood plasma sent to the field. The shipments would spoil until, they used freeze drying methods to preserve them.
Freeze dried fruits are created by placing fresh fruit in a dryer/freezer at -40 degrees Fahrenheit or colder. A heated vacuum forms around the food and the moisture is pulled from the food. The food is then sealed in moisture and oxygen-free containers. The food will be fresh when reopened and moisture is added to reconstitute it.