Start by washing your eggplant completely. The choice is up to you regarding whether you want to peel your eggplant or not, but either way, you will want to do the best job you can to get any dirt or pesticides off your eggplant.
Once you’ve washed your eggplants, you will need to slice them. The best size for slicing is about ¼ inch thick. You can dehydrate with the skin on or off, but make sure you slice extra-thin if you plan on leaving the skin on (the skin is best on young eggplants, too).
You can also choose to cut your eggplant into one-inch cubes. This choice depends on your ultimate goals for how you want to use your dehydrated eggplant. Use the sharpest knife you can find to create these slices. This will allow for even, equal amounts of drying.
Next, you will need to blanch your sliced eggplant. This will not only add flavor to the vegetables, but will also help aid in long-term preservation. Blanch by boiling water or via the steaming process. The steaming process is particularly helpful when you are blanching eggplant for the purpose of dehydration. It allows the pieces of eggplants to retain more nutrients and is also quite easy to do. All you need to do is put the eggplant slices in a strainer that is rested on the top of a pot of boiling water.
Allow the eggplant to steam for about four minutes. You can then place the strainer in cold water to further halt the cooking process.
Next, you’ll need to use the non-stick drying trays on your food dehydrator to layer your eggplant. Spread the slices among the trays in a single layer, allowing no one slice to overlap another.
Set the dehydrator to medium, and place the trays inside, allowing the machine to dry the eggplant for 12 to 24 hours, depending on how brittle you want your finished product to be. You may find that you need to rotate your trays every few hours, moving the bottom trays to the top and vice versa. This will prevent the eggplant slices from becoming too brittle.