Vitamin C Content of Freeze-Dried Tropical Fruits

摘要

Brazil is among the largest producers of tropical fruits in the world. Commercialization of dried fruits hasgained importance worldly due to the search of consumers for practicability and products of great nutritionalvalue. The application of the freeze-drying technique in fruits conservation is the key for a successful of theircommercialization. Freeze-drying is a technique that preserves the flavor, color and nutrients in the finalproduct. Therefore, the aim of this work was to analyze the vitamin C content in fresh and freeze-driedguava, mango, papaya and pineapple. As the freezing is the first stage of freeze-drying process, it was alsoevaluated the influence of type of freezing, such as conventional freezer and cryogenic, in the final product.In addition it was carried out a comparative study between freeze-drying and convective drying techniques.The ascorbic acid content of “in nature”, freeze-dried and hot air dried pulps was determined using the 2.6dichlorophenolindophenol titration. Vitamin C content was utilized as the quality parameter. It was observedlosses of 37.47 to 3.05% for freeze-dried guava, mango, papaya and pineapple, whereas these losses were of49.3% after convective drying. The freezing using conventional freezer resulted in highest vitamin C losses.