Preheat oven to 350°.
Combine first 7 ingredients in a bowl.
Slice each banana in half lengthwise; slice in half crosswise.
Cut 4 (10-inch) circles of parchment paper. Fold each circle in half; open each. Place 4 pieces of banana near fold; top with 1 tablespoon juice mixture. Fold paper over filling; seal edges with narrow folds. Repeat procedure with remaining ingredients. Place packets on baking sheets.
Bake at 350° for 5 minutes or until packets are slightly puffy and contents are thoroughly heated. Place on plates; cut open. Serve immediately.