Preheat oven to 350°.
Line two 12-cup muffin pan with 18 paper liners.
Soak raisins in 1 cup hot water until soft, about 10 minutes; drain raisins and transfer to a food processor. Puree until smooth, about 30 seconds
In a medium bowl, combine bran, flours, baking powder, baking soda and salt.
In a large bowl, stir together yogurt, brown sugar, molasses, butter, egg, and raisin puree.
Add dry ingredients and stir to combine; fold in pineapple.
Divide batter evenly among liners.
Bake until a toothpick inserted in center of a muffin comes out clean, about 25 minutes