After freeze-drying the moisture content was equal to 5, 4, 2 and 7% (wet basis) for guava, mango, papaya and pineapple, respectively. Figure 2 presents the vitamin C content determined for “in nature” and freezedried tropical fruits. It can be observed after the process vitamin C losses of 37.47, 3.05; 6.91, and 27.31% for guava, mango, papaya and pineapple, respectively. The low residual moisture content, inferior than 10% (w.b.), in freeze-dried fruit, allied with the thermal process employed, it may have favored the low vitamin losses, since the degradation reactions rates of ascorbic acid are decreased in dehydrated products with lower moisture content [13].