Hi Linda,

I make muffins at home (low-fat), and I use all-purpose. They turn out ok for me. I don't change the recipe at all.
Here is my recipe, I do at home.

Bran & Raisin Muffins.

1 1/4 cups all-purpose flour
2 Tb sugar
1 Tb Baking Powder
1/4 ts Salt
2 cups of Bran cereal (I use the blender to crush it up a little)
1 1/4 cups fat-free milk (we use 1%)
1 Egg (I substitute this with 2 egg whites)
1/4 cup of Oil (I substitute the oil for 2 Tb Maple Syrup, or a little more OR if you're watching the fat intake, you can add 2 Tb oil instead of 1/4 cup, but don't add the maple.)
1/4 - 1/2 cup of Raisin.

Method:

Preheat oven to 400F
In mixing bowl, stir together flour, sugar, cereal, baking powder and salt. Set aside.
In a large mixing bowl, combine egg (or whites), oil (or maple syrup)and milk. Beat Well.
Add the flour mixture and raisins, stirring only until combined.
Portion evenly into twelve 2 1/2-inch muffin-pan cups coated with cooking spray.
Bake for 20mins or until light browned. Serve warm.*These are yummy if you're trying to watch fat intake etc. Each muffin has 3g fat (0g saturated, if you use fat free milk).

Enjoy!

Nicole