1. Combine sugar and water in a saucepan over meduim heat; stir until sugar dissolves and syrup begins to simmer.
2. Chill. (I assume you're supposed to take if off the heat, first).
3. Cut pineapple in half, lengthwise, leaving crown intact.
4. Remove fruit from both halves, leaving 1/2-inch of fruit inside the rind.
5. Remove core and cut fruit into 1-inch chunks.
6. Place pineapple halves in large plastic bags and freeze until ready to use.
7. In a food processor with metal blade in place, add pineapple chunks and process until pineapple is smooth and uniformly pureed.
8. You should have about 2 cups puree.
9. Add chilled syrup and lime juice. Process 10 seconds.
10. Place mixture in metal tray or bowl and partially freeze.
11. With metal blade in place, place spoonfuls of partially thawed pineapple mixture in bowl of processor.
12. Mix by turning processor on and off about 8 times, then process about 2 minutes until completely blended, smooth and fluffy.
13. With machine running, add egg white through feed tube.
14. Process 1 minute. Refreeze. Spoon into pineapple shells and serve.