Heat oven to 375 degrees F. Line 12 standard-size or 24 mini-muffin cups with papers.
Microwave raisins and water, on high, in covered dish until raisins are very soft, 2 to 3 minutes; stir every minute. Reserve 1 tablespoon liquid; drain off rest. Puree raisins with liquid and vanilla in food processor.
Toast bran on cookie sheet in 375 degree oven 8 minutes, until golden brown. Combine bran, buttermilk, juice concentrate and fructose in large bowl. Stir in raisin puree. Let stand 20 minutes. (Or refrigerate overnight; return to room temperature.)
Sift flours, baking soda and baking powder into separate bowl. Stir egg whites and zest into bran mixture. Stir in flour mixture just to combine. Spoon into prepared muffin tins.
Bake standard muffins in 375 degree oven 28 minutes, mini-muffins 20 minutes, or until crusty. Cool in pan 5 minutes. Remove muffins to cool. Makes 12 standard or 24 mini-muffins. (Nutrition facts are for 1 standard muffin.)