1. Puree soursop in the food processor.
2. Strain the puree and place in refrigerator to chill.
3. Place sugar with 1/3 cup of water in a saucepan over low heat for 5 minutes.
4. Boil the sugar syrup for 1 minute.
5. Chill the syrup in the refrigerator for 1 hour until chilled.
6. Mix the syrup and soursop.
7. Freeze the mixture for 7 hours.
8. After 7 hours of freezing, put the mixture back in the food processor.
9. Freeze for another 3 hours before serving.