Things You'll Need
Cake cooling rack
Freeze dried foodstuffs have become so popular that you might have seen them at your grocery store. This type of food preservation is steadily gaining popularity because you do not have to add any preservatives yet you can safely store food for many years without damaging its nutritional structure or taste. In fact, most freeze dried foodstuffs can be completely revitalized by putting a little hot water in. You will be surprised that the taste and texture remain pretty much the same as prior to freeze drying.
Freeze drying bananas involves removing water from the fruit by sublimation, while leaving intact the structure and composition of the food. Microorganisms that cause food spoilage thrive on water. Natural enzymes of the banana need water too; by dehydrating the fruit, it ceases ripening. The simplest freeze drying procedure requires a little preparation and a common of household appliance, the freezer.
Freeze Drying Bananas
Prepare the bananas by peeling off their skin and setting them on a clean container or cooling rack. Make sure the bananas have no rotten spots.
Slice the bananas into thin chips. Slice them almost paper thin, if possible. Slicing the fruit thinly allows rapid sublimation (changing from solid to gas and skipping the liquid phase) when subjected to freeze drying.
Arrange the paper thin banana slices on a rack or a tray then put them in the freezer. Arrange them or further exposure to room temperature can discolor the fruit. It's best if the freezer is frost-free so there is only the presence of cool, dry air.
When approximately seven days have passed, take out the dehydrated banana chips and let them thaw. Notice that they have completely dried out and look just like the banana chips you see at the grocery store.
It's helpful to lower the freezer temperature to allow it to quickly freeze dry the chips. Check the freezer from time to time to see if the bananas are actually freezing.