The Science Behind Taste

Taste is basis of the culinary arts and is one of the senses we use to identify the food we eat. Taste benefitted early humans by indicating which foods were safe for consumption. Sweetness signaled foods with calories for energy, while sourness could indicate the presence of vitamin C; bitter foods were potentially poisonous, whereas salty foods contain important minerals and other nutrients.  For a long time, it was believed that there were only these four classifications of taste – until the recent discovery of a fifth, entirely different “taste”

The Taste Buds
The original set of tastes that many people learned about in elementary school consisted of four main tastes: bitter, sour, salty and sweet. We perceive these tastes via our taste buds. The old-fashioned “map of the tongue” where different taste buds were thought to occupy their own specialized regions is now believed to be largely incorrect; however, those four tastes are still the ones with which most people are familiar. Up until fairly recently, they were considered the only ones.

Note that while the taste buds may not be strictly specialized as implied by the tongue map, some do react more strongly to some chemicals than others. For instance, some react more to salt while others react more to bitter or to sweet.

How Taste Workstaste2
Contrary to what many people believe, the small bumps on your tongue are not your taste buds, they are called papillae. These papillae contain the taste buds. The taste buds themselves are made up of receptor cells that have hair-like protrusions that enable them to be stimulated by food molecules. When the food molecules stimulate the receptor cells this creates the sensation of taste. Of course, for the molecules to get to the receptor cells the food has to be dissolved, that is one of the functions of saliva.

The Role of Smell
The smell of food triggers an increase in saliva production as well as the production of digestive juices in the stomach. This is all in preparation to taste and then digest food. Much of the sensation of taste is due to smell since humans can discern only a few tastes but recognize thousands of smells.

What is Umami?
Modern scientists believe that there are five tastes, not four; umami is widely considered the fifth taste. Umami is the taste of glutamate, which is found in parmesan cheese, soy sauce and tomatoes. The concept of umami is difficult to define but is often described as “meaty” or “savory.”

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The History of Umami
Kikunae Ikeda, a Japanese chemist who was searching for a taste sensation that was different from the primary four, discovered the flavor known as umami in the early 20th century. While Ikeda’s writings would not be translated to English until 2002, other scientists continued to study the flavor in the years after its discovery. Results of research in 1985 indicated that umami could not be replicated using the four basic tastes, thus strongly indicating that it was a fifth taste.

Umami in the Culinary Arts
While the idea of an umami flavor may be relatively new in western culinary arts, it is a staple in Japanese foods. The seaweed stocks (“dashi”) used in many Japanese dishes adds the umami flavor to those dishes.

Scientists have discovered that along with the receptor cells for the four main tastes, humans have ones for glutamate as well; this is another reason that it is considered the fifth taste. Furthermore, glutamate indicates the presence of amino acids. This means that just as sweet, sour, bitterness and salt may signal the nutritional value of certain foods, so might umami.