Dehydration only minimally affects the nutritional value of foods, especially when the process takes place in your own home. Most research on the nutritional value of dried foods has been conducted on foods that are commercially dried. When you dry foods at home under gentle conditions (correct temperature and a reasonable amount of drying time), you produce a high-quality product. Compared with canning and freezing, both of which involve extreme temperatures, food drying is the least damaging form of food preservation.
Here are some specifics:

• Vitamin A is retained during the drying process. Because vitamin A is light sensitive, foods that contain it-like carrots, bell peppers, mangoes-should be stored in a dark place.
• Some vitamin C is lost during the drying process because vitamin C is an air-soluble nutrient and food drying is an air-based process. When a food is sliced and its cells are cut, the surfaces that are exposed to air lose some vitamin C content.
• The caloric value of a fresh food stays the same when it is dried, although some dried foods, fruits for example, taste sweeter because the water has been removed and the sugar is concentrated.
• Dried fruits and vegetables are high in fiber and carbohydrates, neither of which is affected by drying.
• Dried fruits and vegetables are naturally low in fat. Minerals available in certain fresh fruits-such as potassium, sodium, magnesium, and so on-are also not altered when the fruit is dried.