Bring the chicken broth to a boil in a medium saucepan. Add rice; cover, reduce heat, and simmer 45 minutes or until liquid is absorbed.
Preheat oven to 400°.
Combine the sweet potato and 1/2 teaspoon oil in a bowl, tossing well to coat. Arrange sweet potato in a single layer on a jelly-roll pan. Bake at 400° for 30 minutes, turning once.
Combine diced apples with orange juice concentrate in a small bowl. Drain, reserving concentrate. Combine 1 tablespoon oil and reserved concentrate; stir well with a whisk.
Combine rice, concentrate mixture, apples, green onions, and raisins; gently stir in potato. Cover and chill 1 hour. Garnish with mint sprigs, if desired.