I bought a bag of peeled garlic cloves as a convenience(I know, shame on me) I stored the unused cloves in the fridge and the began to show purple areas on the cloves. I don't think this is anything harmful but my partner didn't like it and insisted I throw away what was left. Is this just another natural color change for garlic such as the blue/green or green colorations that can occur. Anyone have a definitive answer? I'm not trying to one-up her, just trying to be safe.
The purple is just the anthocyanins in the garlic reacting to conditions. It's perfectly safe. Some types of garlic actually turn purple before they are picked if they are fertilized close to maturity; I do this now by choice, because I've decided I like the purple. The purple will occur more frequently and to a greater degree if the garlic is cooked with or peeled cloves are stored in contact with something acidic.