In a small saucepan, combine Spenda and cornstarch. Stir in orange juice until smooth. Bring to a boil; cook and stir for 2 minutes or until thickened. Remove from the heat; stir in orange extract. Cool.
In a large serving bowl, combine the pineapple, oranges, apples and grapes. Add enough dressing to moisten fruit (I didn’t need all of it); stir gently. Cover and refrigerate until serving.