Do foods with preservatives become less toxic in the gut?
Do foods with preservatives take longer to digest?

Food preservatives are either antimicrobials (e.g. sorbate, sulfite) or antioxidants (free radical scavengers such as butylated hydroxyanisole).

Digestion is initiated in the stomach by hydrochloric acid and pepsin. It continues in the small intestine with the action of numerous other enzymes including amylases, lipases and proteases. There is no obvious way that these digestive processes would be inhibited by preservatives.