The extensive polymorphism and the small size of the fruits of Cherimoya (Annona cherimola, Mill.), known in Italy under the name of "annona", influence the marketability of this product. Further more annona derivatives are very sensitive to enzymatic browning even during storage in the frozen state. The objective of this research was to verify the effectiveness of combined pretreatments on the prevention of enzymatic browning during freezing and thawing of annona puree. In particular the combination of two or more "mild pretreatments", which separately are incapable of obtaining complete control of browning in vegetal tissue, was studied. Results showed that the addition of 2 g . kg(-1) ascorbic acid plus 2 g . kg(-1) citric acid with or without 1 g . kg(-1) sodium chloride to annona puree allowed complete browning control during freezing, storage and thawing.
