In a blender, combine about 1 cup frozen pineapple chunks, 1/2 cup frozen unsweetened strawberries, and 1 peeled ripe banana (about 3 oz.) cut into chunks. Add 1 cup orange juice and 2 to 3 tablespoons plain malted milk powder. Whirl until mixture is very smooth. Pour into 2 tall (at least 10-oz.) glasses.