Some issues that may occur:
Bread sticks to pan. Unless you’re using high-quality nonstick metal or silicone baking pans, you should always grease the pans before you pour in the batter. The best thing to use for greasing the pan is shortening, because its melting point is higher than any other kind of fat, which helps maintain a “shield” between pan and batter while the bread is baking. A high-quality cooking spray–one that won’t bake on to your pans and discolor them–is also a fast, easy fix. You can also prevent sticking by removing the bread from the pan when it is completely cooled. As it cools it should “shrink” and then come out easily.
There are big holes and “tunnels” in the bread, and/or the bread is tough. These problems are usually caused by over-mixing..
There’s a big crack down the middle of the quick bread loaf. The crack on top happens when top of the loaf “sets” in the heat of the oven before the bread is finished rising. Don’t worry–it’s normal for quick breads. Drizzle the loaf with icing or dust with confectioners’ sugar.
My blueberry muffins look green! By reacting with the alkaline baking soda, the blueberries’ pigments can turn green. Toss the berries with the flour mixture before combining the ingredients; the coating should help. If you’re using frozen berries, don’t thaw them before using them.
The bread looks done on the outside, but it’s still raw in the middle. This is one of the most common quick bread problems, and it can be caused by a few different factors. The oven temperature could be too high. Try lowering the oven temperature and/or putting a loose tent of foil over the top of the bread, so it won’t burn before the middle has time to catch up.