You're not really tasting what's mixed in; it's actually the garlic that is different. Cutting or crushing garlic starts a chemical reaction between two chemicals in the garlic called alliiin and allinase, which produces allicin. Allicin is the characteristic flavor of garlic that's somewhere between fragrant and overpowering. Using pre-cut garlic means that these chemical reactions, and other reactions, have had a lot of time to progress.