Monday, November 25, 2013

Umami, the 5th Taste!

In school, I can't recall ever learning about a 5th basic taste called umami, besides the sweet, sour, salty and bitter tastes. Given that 'umami' was only formally recognised as the 5th basic taste in 1985, I guess our text books would have to take a few more decades to record the updated information (I have yet to peruse the current text books to spot the updates).

It is interesting that from a very young age, most of us who've been little kitchen helpers of our moms would have heard her say that we need to add in enough meat to a soup or a stew in order for the dish to have a meaty sweetness or roundness taste to it. And all this while I never knew that that taste was the umami taste - difficult to put into words but all of us know what it is.

The word 'umami' itself would give us a clue about the person who had discovered (or rather, first proposed) this 5th basic taste - a Japanese chemist Kikunae Ikeda from Tokyo Imperial University (now known as University of Tokyo) in 1908. The word umami is derived from Japanese words, 'umai' (delicious) and 'mi' (taste), which literally was meant to mean a pleasant savoury taste. When I read of this, it was a light bulb moment - I'd always told people that I preferred salty/savoury foods to sweet foods, which was actually inaccurate, I prefer umami foods!

When thinking of food categorised as umami, one cannot separate the idea of Asian food (particularly Chinese food) and Ajinomoto. Chinese cooking is infused with fermented bean/fish sauces and MSG (monosodium glutamate), which makes it so delicious! MSG is synonymous with Ajinomoto (which the company name translates to "essence of taste"), but there are other producers in the market as well.

The first idea of umami came from a bowl of seaweed soup (kombu) and I guess only a chemist would think of finding out what caused the soup to be so delicious. So he did and turns out the that savoury taste is from glutamate, a non-essential amino acid abundantly found in us (no wonder we taste so yummy! haha just kidding). Foods which give the umami taste include ripe tomatoes, fermented foods, cheese, meat, kombu, shiitake mushrooms, bonito flakes and Chinese cabbage. From what I read (and also agree on), the umami taste is accentuated when there is a combination of the aforesaid foods with other types of food (synergistic effect of ribonucleotides GMP & IMP and glutamate).

It is interesting that our first exposure to umami was in the form of breast milk (for those who'd been breastfed). Breast milk has the same concentration of glutamate as soup stock, which explains why we find soup stock just right in terms of the wholesomeness of taste. What makes it so agreeable with our taste buds is the carboxylate anion (COO-) on glutamate which binds with specific receptors we have on our tongues.

Remember the tongue sensory areas, where certain taste receptors are concentrated at certain areas on our tongues? I sure do remember the textbook diagram but can't recall which taste senses were more prominent in which sections of the tongue! Perhaps one day I'll find that the said diagram would've been revamped in the textbooks of our future generations! (Although I have not read up on which area of the tongue is sensitive to the umami taste.

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