flavor thief
A flavor thief is an ingredient in a dish or beverage that overpowers the taste of every other ingredient. Some examples include bananas in a smoothie as well as tomatoes in a sandwich.
Sam: "I made a huge mistake getting tomatoes in my sub."
David: "Oh man, tomatoes are a huge flavor thief, I hope your mouth is ready."
David: "Oh man, tomatoes are a huge flavor thief, I hope your mouth is ready."