On the wiki page for umami, it says that tomatoes are "rich" in umami components.
Does that mean it is redundant to add umami (such as monosodium glutamate) or soy based flavorings to tomato-based sauces, or is there a benefit?
For example, a typical tomato-based sauce is cocktail sauce, which often has worcestershire sauce in it as an ingredient. However, the main active component of worcestershire sauce is fermented fish sauce or soy, which is primarily valued for its umami. So, if umami is already present in the tomatoes, why add the worcestershire at all?