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.