Just about anything edible, my favorite is vegetables. Vegetables are so expensive, and a lot of them go to waste. Instead of wasting them, I chop them and dehydrate them.
They are great to use as quick flavor, and or color, to sauces, soups, meatloaf, burgers, or anything else you cook. Make sure you rehydrate them long enough.
If you don’t have a food dehydrator and need to buy it, make sure you read best food dehyrator reviews. So, you can know what is the dehyrator suits your needs.
My favorite is to keep a mixture, add some to ramen noodles, throw in a can of chicken, or other canned or dried meat, and end up with a hearty meal. You can also dry them, process them in your blender, and you have great seasoning.
Try grinding dried potatoes to use as a thickener as well as adding flavor. There has been many a day I might have gone hungry had I not saved those things, others call scraps.
How does dehydrating food change its nutritional value? Dehydrating just removes the moisture. It's nutritional values are probably still the same, because water, in and of itself, has no food value inherent in it, although it's vital for life and digestion.