1. Preheat the oven to 375 degrees. Spray a 9 by 5 inch loaf pan with cooking spray. 2. Stir together the flours, baking powder, and salt in a large bowl. Whisk together the sugar, egg substitute, butter, yogurt, buttermilk, lemon juice, lemon peel, and extract in a medium bowl. Gently fold the sugar-egg mixture into the flour just until combined. Gently fold in the blueberries. 3. Pour the batter into the prepared pan and bake for 55 minutes, or until the top is lightly browned and a knife inserted in the middle comes out clean. Cool for 5 minutes before slicing.