This blueberry oatmeal bread recipe says to add 2/3 cup dried blueberries to the bread machine at add-in time. When I just dump them in on top of the dough, they end up clustered at the bottom of the loaf, as shown:     (How) can I get them to be evenly distributed?  Update  As bob1 suggested, I tried adding the dried blueberries at the very start. That worked. The blueberries were evenly distributed and none the worse for the earlier inclusion.   
The Wikipedia article you link actually hints at an answer. It points out that there's a synergistic effect when combining different classes of umami-rich foods, leading to a greater flavour enhancement than would be expected simply by adding the effects of the ingredients      Japanese make dashi with kombu seaweed and dried bonito flakes;... and Italians combine Parmesan cheese on tomato sauce with mushrooms.   So it's certainly traditional. But in your example the tomatoes bring some sweetness along with the umami, while the Worcester sauce (like soy sauce) is salty and so rich in umami it's used in small quantities. The effect of combining them is a more savoury sauce than one that tried to get all its umami from tomatoes. Red pesto uses parmesan to similar effect.  