Preheat the oven to 400°. Spray a 12-cup nonstick muffin pan with oil. In a large bowl, whisk the flour with the oat bran, brown and granulated sugars, baking powder, baking soda, salt and cinnamon. In a food processor, puree the ricotta with the buttermilk. Add the milk, melted butter, vanilla, egg and egg white and pulse until smooth. Add the bananas and pulse just until blended.