SAST Wingees

A Question of Taste – How many is it – 4 or 5 or 6?

As a Tamil, I often encounter the assertion that there are actually 6 tastes and the scientific world (read western) is simply wrong in recognizing only 4 tastes –  Salty, Sweet, Sour and Bitter. The 6 tastes in Tamil are – Uppu (Salty),  Thithippu (Sweet), Pullippu (Sour), Kasappu (Bitter), Uraippu (Hot) and Thuvarppu (Taste of Plantain Flower). It is a fact that the Scientific World has been somewhat reluctant in agreeing to revisit the issue of whether there are more than 4 tastes. Consider the case of Umami, which has now been accepted officially as the fifth taste. A Japanese researcher Kikunae Ikuda identified this taste in the year 1908 and fought the scientific
establishment as the lone crusader. Finally, in the year 2000, Umami entered the world of taste as the official fifth taste when a research team in the University of Miami isolated the receptors responsible for detecting the taste of Umami. The most familiar example of an “umami” taste is that of  Monosodium Glutamate (MSG). Coming back to the 6 tastes in Tamil, my curiosity got piqued when I read Mark Kurlansky’s mention that the Chinese have 6 tastes in his book Salt. The 6 tastes in Chinese he lists are – La (Hot), Tian (Sweet), Suan (Sour), Xian (Salty), Ku (Bitter), Ma (Taste of Spicy Huaojiao). At this point, I thought if the Chinese Ma and the Tamil Thuvarppu are similar, maybe there is a case for the sixth taste. So I decided to investigate this matter. First, I consulted my goto Chinese experts Tom Chen and his mom Winnie Chen about Ma. They came back almost immediately and said that Ma actually refers to the numbness that results from tasting Huaojiao and cannot reallly be considered a taste. Huaojiao is supposedly a very very hot pepper. (Thanks Tom and Winnie). Then I turned my attention to the Tamil Thuvarppu. I know this taste very well having tasted dishes made of Plantain Flowers and other items known to give off this taste like Betel nuts etc. I searched on the Internet but could not find any mentions of this taste at all. At this point, I was brainstorming with Priya Raju as to what this taste could be. She knows this taste very well as well. During the discussion, she got a brilliant brain wave and said –
“I have tasted Red Wine and it is similar to the Thuvarppu taste and I also know that that flavor comes from Tannin which is a flavanoid found in Red Wine. So I think Thuvarppu is also coming from Tannin”. Both of us immediately started searching the Internet and voila Plantain Flowers do have a heavy content of Tannin. So we concluded that the Thuvarppu taste is  not really a taste but a flavor resulting from Tannins. It turns out that most fruits when
they are raw have a lot of Tannin which is supposedly an excellent insect repellant. For instance, a raw banana gives off the Thuvarppu taste due to its Tannin content. In scientific terms, Tannin binds with the receptors for Bitter and also triggers an astringent sensation in the tongue both of which combine to give the Thuvarppu taste. In sum, Thuvarppu is a flavor and not a taste. Having figured that out, one question still remained – is Hot a taste? Hot peppers have an alkaloid called Capsaicin which actually causes the sensation of heat. It does this by binding to the pain receptors in the tongue. So Hot is also not a taste but a flavor. Its amazing to know that about 75% of what we think as taste comes from its smell. That is why, when you catch a cold, you cannot accurately determine the taste of food stuff. References:
1. Wikipedia article on tastes with references to Umami.
2. Article in Nature Neuroscience announcing the discovery of Umami receptors by Chaudhary et. al.
3. Very well written tutorial on Taste by Tim Jacob. Must read.
4. Tutorial on smell by Tim Jacob. must read.
5. Society for Research on Umami Taste.