Freeze drying sublimes frozen water out of frozen produce, under vacuum. I have heard that the "pores" in food remain open under vacuum meaning that the food can be dried more effectively than...:
Dehydrating typically involves evaporating liquid water out of room temperature, or even slightly warmer, produce
If I were to guess, nutritionally, keeping food at a higher temperature until the water evaporates may lead to certain nutritional components degrading more than if the produce is frozen. Query also the likelihood of bacterial spoilage. |