【Taste Mechanism】

Five basic tastes

As for current medicine and psychology, it is generally believed that there are five kinds of tastes, which refer to sweet, umami, salty, sour, and bitter taste, which are the taste senses detected by the tongue or the sensory organs present in the mouth - taste buds. These five kinds of tastes are also called "five basic tastes" or "basic five flavors".

However, according to the past conclusion, it does not include umami flavor, only four basic tastes. However, due to the development of molecular biology in recent years, scientists have found that umami flavor also has a separate receptor, and its taste nerves can also transmit umami information, and other special tastes that cannot be conveyed by other tastes, so umami flavor is recognized as one of the basic tastes. This classification of basic tastes is not only molecular biology, but also medicine and psychology. Unfortunately, there is still no English saying equivalent to umami flavor, so academic terms are first expressed in Japanese Umami flavor. 100 years ago, published by Professor Kikunoha Ikeda University of Tokyo, and a paper on extracting ingredients from Kumbu, the expression method of "Umami" was used. Later, it gradually became a fixed expression method in the academic community.

Personal differences in taste feelings:

Currently, research has shown that the sweetness threshold limit (=blunt) of children under the age of 3 is known to decrease afterwards; the sourness threshold limit for girls aged 3 to 5 is the same as that of adult women, but boys aged 8 to 9 are also higher in sweetness, saltiness, and sourness threshold limits than adult men. This may be related to the fact that children must intake glucose, citric acid and minerals that are indispensable for musculoskeletal growth in order to grow.

Taste and five senses:

Have experience in smell contact.

The sensations that should have been felt individually are mixed together, which is called "synesthesia", also translated as "synesthesia". For example, when someone hears a single word, he will see a certain color, and researchers call this kind of human being a "synesthesia" of sensation. The color-sensory area in their brain (the 8th area of ​​the visual area of ​​the cerebral cortex) will react to sound. In addition to synesthesia of sensation, some people also feel the sense of taste, and they also feel the touch of the palms when they feel the sense of smell; or when they feel the sense of smell, they will also see the color, etc. These people are collectively called "synesthesia".

Not everyone will have the above synesthesia reaction, and the generation of synesthesia is not very related to daily life experience. On the other hand, many people will mix taste and smell together, which is actually a phenomenon caused by personal experience. Therefore, the mixture between taste and smell is also described by scientists as "learning synesthesia."

There are differences in the way of feeling spicy. When you take the first bite of curry, you may feel that "I can do this spicyness", but after eating a few more bites, you feel that it is too spicy to bear it. This situation should be quite common. In the fields of medicine and psychology, this phenomenon is called "sensitization". On the contrary, if you wait until the spicy feeling disappears and take another bite of curry, you will feel that it is fine. This phenomenon is called "desensitization". However, even in the desensitivity state, if you continue to eat, you will still feel that it is getting spicy and it will not be able to bear it. This phenomenon is called "stimulus-induced recovery".

If you rinse your mouth with a sour (citric acid) solution or a sweet (sucrose) solution, the stimulation of spicy will become weaker. In contrast, when rinsing your mouth with a bitter (hydroquinine chloride) solution, although the stimulation is slightly weakened, the effect is not as obvious as the sour or sweet taste. According to the results of this study, when we eat spicy food and feel it is very spicy, drinking some sweet and sour drinks (lemonade, etc.) can effectively suppress the spicy taste in the mouth. Indeed, the spicy curry provided by Indian restaurants is often combined with Indian Rassi (Lassi sour and sweet yogurt). As long as we know the mechanism of the mouth, we can understand the reasons for this combination.

There is a strong correlation between temperature and basic taste. Simply put, the closer the temperature of taste stimulation is to the body temperature, the more sensitive it feels. Warm carbonated beverages and melted ice sores will be so sweet that people cannot drink (eat), which is the result of this phenomenon. Therefore, in order to allow us to eat the taste at low temperatures, the seasoning of these foods and beverages is usually heavier. The reason why this is this is because the chemical reaction of the substances contained in the food and taste receptors is most effective when it is closest to the temperature of the organism.

Drinks with dark colors make people feel stronger. Judging from daily experience, readers should not be difficult to understand. On the other hand, from experience, red is the color of ripe fruits, which may make people feel a strong sweetness; while green is the color of unripe fruits or fruit juices, which may make people feel a strong bitterness, but experiments cannot find that the results of red beverages affecting taste assessment. On the contrary, most reports point out that red will not affect the taste threshold of any of the five basic tastes, nor will it affect the taste intensity assessment value on the threshold.

Let’s introduce a few experiments on actually using food and beverages.

French experiments:

In the experiment, the red pigment was added to the white wine to make it look like red wine. The subjects were a group of students studying at the University of Bordeaux, France in order to obtain national qualifications related to wine (oenologues winemakers).

First, the subjects were asked to taste red wine and white wine, and they could tell the difference correctly like sommeliers and red wine critics.

Then the subjects were provided with a white wine and asked them to use words to describe the taste of the white wine. As a result, the words they used to describe are all vocabulary that are generally used to describe the taste of the white wine.

Afterwards, a small amount of red pigment (anthocyanins) was added to the same white wine to make it look the same as red wine.

Then, the same group of subjects were asked to describe the taste of this glass of fake red wine. This time they used words to describe the taste of red wine to illustrate that the illusion caused by color would also occur to red wine experts (winemakers or sommeliers, etc.).

Similarly, beer experts make the same mistakes when evaluating the taste of beer.

Japanese experiments:

Use the computer to change the color of the tuna sushi photos to blue, red, white and yellow. Then ask the subject to wear glasses-shaped screen to look at these photos and try out the real tuna sushi.

The experimental results show that when eating tuna with sushi when looking at yellow (cream) photos, the fishy smell is weaker and better when looking at red photos.
Chapter completed!