Preheat your oven to 350°F (175°C).
Line a muffin tin with parchment paper or muffin liners.
In a large mixing bowl, whisk together the water, buttermilk or yogurt, vegetable oil, egg, and egg white until well combined. Add in the fresh orange zest and stir to incorporate.
In another bowl, combine the wheat bran, flour, whole wheat flour, brown sugar, baking powder, baking soda, and salt. Mix until thoroughly combined.
Gradually add the dry mixture to the wet mixture, folding gently with a rubber spatula until just combined.
Gently fold in the dark raisins until evenly distributed throughout the batter.
Spoon the batter into the prepared muffin tin, filling each cup about 3/4 full.
Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Allow the muffins to cool in the pan for about 5 minutes before transferring to a cooling rack.