Drain pineapple, reserving 3/4 c. juice.
In saucepan, combine sugar and cornstarch.
Add pineapple juice, orange juice, and lemon juice.
Cook and stir over med. heat until thickened and bubbly; cook and stir 1 min. longer.
Remove from the heat; set aside.
In a bowl, combine pineapple chunks, oranges, apples, and bananas.
Pour warm sauce over the fruit; stir gently to coat.
Cover and refrigerate.