Why are my muffins sour?

Question

So about a week ago I made blueberry bran muffins with these ingredients:

1/2 mashed banana
1 cup whole wheat flour
1/4 cup all purpose flour
1/2 tsp salt
1 tbsp cinnamon
2 tbsp applesauce
2 egg whites
2 cups All Bran cereal
1 tbsp splenda brown sugar

I put a tablespoon of blueberries in each muffin.

They tasted fine (I think) the other times I had them but this morning, they tasted disgustingly sour! Did the banana in the muffins go bad?

What went wrong?
Should I change my recipe a little?

Answer 1

Sounds like the muffins did go bad.

To preserve muffins longer, I would suggest after baking let them cool to room temperature and then store them in air tight containers and refrigerate. This way they should stay good for about a week or so. But if you want to store them for a longer period then place them in air tight containers and and freeze.

Answer 2

Do you usually make them with blueberries? Blueberries can have a sour taste when cooked. Also, it doesn't seem like there was enough sugar to balance out the sourness of the blueberries.

Answer 3

I would think it's more likely the blueberries caused the problem. This should work better if you add frozen blueberries, rather than fresh ones. Probably you should eat them all within 4 days or refrigerate them.

Answer 4

Sounds to me that they are spoiled or starting to mold. I wouldn't eat them