First, preheat the oven to 250 degrees. Second, stir together the flour, sugar, baking powder, baking soda and salt in a bowl. After that, mix the egg, yoghurt, milk, oil and orange juice in another bowl. Then, add the mixture to the first bowl together with the diced apple and raisins and stir well. Finally, put the mixture into 16 muffin cups and bake for 20-25 minutes.