If we leave glycogen in our mouth for seconds/minutes, would the acids in our mouth decompose it into glucose which would taste sweet? Yes, I have no knowledge about chemistry.
Nope. There is no acid in the mouth, and acid doesn't break down carbohydrates anyways, its all enzymes in the intestine.
Amylase, the thing in the mouth, breaks down starches, like in rice or bread. Glycogen is different from these though, as it has different linkages, and can't be broken down by amylase.
