Heat oven to 400º. Grease bottoms only of 12 medium muffin cups, 2 1/2x1 1/4 inches, or line with paper baking cups.
Beat milk, oil, juice concentrate, 2 teaspoons orange peel and the egg in large bowl until blended. Stir in flour, 1/2 cup sugar, the baking powder and salt all at once just until flour is moistened (batter will be lumpy). Fold in currants. Divide batter evenly among muffin cups. Mix 3 tablespoons sugar and 1 teaspoon orange peel; sprinkle over batter in cups.
Bake 20 to 25 minutes or until light golden brown. Immediately remove from pan.