Amazing Interplay: Basal and Synergistic Umami

In the explanation that follows, we will refer to the two aspects of umami as a basal contribution, based on free glutamate, and a strengthening or synergistic contribution, which is due to the presence of 5’-ribonucleotides.

The fantastic synergy between glutamate and nucleotides can best be illustrated by a simple example. The threshold for being able to taste pure glutamate in water is 0.01–0.03 percent weight/volume (w/v). But if a small amount of inosinate, which has no taste, is also present in the water, the threshold falls to 0.0001percent w/v, about one hundred times less. (See the tables at the back of the book.) Guanylate is more than twice as effective as inosinate. We also know that there can be similar synergistic interactions between different substances that produce a sweet taste, but they are far less powerful than those associated with umami.