The small vitamin C losses in freeze-dried guava, mango, papaya and pineapple are attributed to the low temperatures and to the use of vacuum in the process. In addition, the final structure of freeze-dried tropical fruits, which were neither collapsed nor sticky, probably contributed for the preservation of vitamin C in the product. It must be pointed out that, due to the highly porous structure of freeze-dried products [4], an inadequate storage may cause oxidative reactions, leading to additional losses of vitamin C in the final product. Then, to ensure the quality of the lyophilized products, metal packaging, polyethylene and polyethylene double layer must be used to storage.