Dried Fungi

When rehydrated, fungi are the raw ingredients that contain by far the most guanylate. (See the tables at the back of the book.) Shiitake and matsutake mushrooms, along with morels, top the list. Dried shiitake mushrooms also contain large amounts of free glutamate and hence can contribute both basal and synergistic umami. Yeast, which is also a fungus, plays a very special role, as the yeast cells contain a great deal of glutamic acid. If the individual yeast cells are split open, the cells’ own enzymes can break down their proteins by hydrolysis, thereby releasing large quantities of free glutamate. This process is exploited in the industrial production of yeast extract, as we will see later. Yeast extracts are widely used in commercially processed foods to add umami.