The letter U proved to be a difficult one, perhaps only slightly less difficult than Q or X. I finally settled on a food-related term that I learned only a few years ago.
Growing up, I learned that our sense of taste was divided into four "basic tastes": sweet, sour, bitter, and salty. I also learned that the taste buds associated with each of these tastes were not uniformly distributed -- instead, certain regions of the tongue featured more or less buds for each of the four tastes. As it turns out, we have more than four basic tastes, and our taste buds are relatively homogeneously distributed across the tongue. The former is the subject of my post today.
The fifth basic taste is sometimes called savoriness or meatiness, but the term that seems to have gained the most traction is umami. Umami comes from Japanese and means "pleasant savory taste." It is a flavor caused by the presence of glutamate or certain ribonucleotides in food. It is because of umami that monosodium glutamate is such an effective "flavor enhancer" -- and it is not surprising that MSG was used so frequently in Asian food, because the Japanese and Chinese have been using seaweed extracts and other natural ingredients that contain MSG for centuries*. If you are interested in a brief description of the biochemistry and interesting properties of umami compounds, I suggest the Wikipedia article.
*I own older Chinese cookbooks where practically every recipe calls for MSG. And while most people think that MSG is bad for you, there is no compelling evidence for this, and in fact many foods contain sources of glutamate just as substantial as MSG.