If you ever tried Sushi and found it so delicious, there is a scientific reason.
Let me explain.
This is from my recent talk at Food Science and Teach @ UC Berkeley, "The Science of Sushi."
Maybe you've heard of Umami. If you haven't, it is the so-called fifth savory taste. The word originates in Japanese, "Umai", which means delicious. So, Umami loosely means Deliciousness (in my opinion).
The more umami in the food, the tastier we humans find.
So, which food has Umami?
Cheese is a great example. So are tomatoes and mushrooms. Guess what you can make with cheese, tomato, and mushrooms?
Pizza!
Mushroom pizza with tomato sauce and cheese is a prime example of a dish packed with Umami deliciousness.
No wonder Pizza is so popular around the world.
Umami multiplies Now, there are three kinds of umami: Glutamate, Inosinate, and Guanylate.
Any one of these will give you a good savory flavor. However, when we combine any two of them, we taste umami in the food three, four, or five times more than when there is only one kind of umami.
Glutamite, x Inosinate Glutamite x Guanylate
Let's look at how much Umami is in Mushroom Pizza.
Cheese (Parmigiano) 1000 - 2700mg Glutamate
Tomato 200mg Glutamate
Mushroom 150mg Guanylate
Did you see both Glutamate and Guanylate in mushroom pizza?
Yes. Again, this is why humans find mushroom pizza savory.
Umami in Sushi Here is a classic example of Umami in Tekka, Tuna roll.
Tuna has both glutamate and Inosinate so by itself; it's already savory.
Nori has a lot of Glutamate - 1300mg.
When you dip this into soy sauce, there is another 1500mg of glutamate. No wonder a Tuna roll with soy sauce tastes good to us because it is packed with Umami.
So, here is an idea.
If we want to increase the umami of Tuna roll, what could we add?
Mushroom could work since it has Guanylate, but there is another traditional Japanese ingredient: Katsuo Bushi, Bonito Flakes, which is packed with Inosinate acid, 2000mg!