Is there an expiation for inadvertently consuming food, some of whose ingredients were made lawful by alcohol?

If the alcohol added to cakes transforms into another non-intoxicating substance before being mixed, then it becomes pure and permissible to use. However, if it is added while still in its intoxicating state, it renders the cake impure, and a Muslim would be sinful for intentionally consuming it. But if one is forgetful or ignorant of its presence, there is no sin upon him.