The Birth of the Fifth Basic Flavor: From the Discovery of MSG to the Internationally Recognized Culture of "Umami"

Flavors can be broadly divided into two categories: one is the flavor of fresh foods such as fruits and vegetables, which are inherent to the food. The other is the flavor produced through cooking and processing, such as the flavors of roasted meat, roasted coffee beans, and soy sauce. Fruity aromas are very popular. There is a wealth of research on the components of fruit aromas. The main components are fatty acid esters and terpenes, in addition to many trace components. These substances combine to form the unique flavors of various fruits.

When fruit ripens, it undergoes incomplete respiration due to insufficient oxygen, producing some ethanol. Ethanol reacts with organic acids in the fruit to form esters, which become the main components of fruit aroma. Judging whether a food is delicious can be based on its appearance, aroma, and texture, but taste is paramount. Eastern cultures generally take a holistic approach, while European cultures tend to analyze. Based on the fact that all colors are composed of three primary colors, many European and American scholars believe that the taste of food is also composed of a combination of basic tastes.

Among them, the most famous is the "Four Basic Flavors Theory." In 1916, the author of this theory proposed that all flavors are composed of combinations of sweet, salty, bitter, and sour tastes-that is, all flavors are produced by the combination of these four basic flavors. However, the umami flavor of seaweed and dried bonito flakes, which we experience firsthand, is not included in this list of basic flavors. H. Stone believed that the umami flavor of monosodium glutamate (MSG) is a mixture of 9% sweetness, 63% sourness, 23% saltiness, and 4% bitterness. There is no equivalent term for "umami" in Europe and America.

A similar expression is "enhancing flavor." In 1985, at an international symposium on taste held in Hawaii, the Japanese pointed out that no matter how the four tastes of sweet, sour, bitter, and salty are combined, umami will not be produced, and explicitly stated that umami is also a basic taste. This view has been internationally recognized, and "UMAMI" has become the internationally accepted term. The discovery and synthesis of umami components in dried bonito flakes and shiitake mushrooms, among other things, confirms that the umami component in kelp is monosodium glutamate. Most research on umami was conducted by the Japanese.

Is spiciness a basic flavor? While the trend of eating extremely spicy food is a thing of the past, spicy foods like curry, tortillas with 80% chili peppers, and pollock with wasabi remain popular. Spiciness is an indispensable flavor in cooking, but it's not a basic flavor. A basic flavor refers to a sensation felt only by the tongue. In English, spiciness is expressed as "hot." There was a past custom of putting chili peppers in boots to warm feet. Damp cloths made with mustard are still used in medicine today.

Spicy flavors increase blood flow to the skin, making you feel hot, and of course, they strongly irritate the oral mucosa. Broadly speaking, spiciness is an important taste, but it's not a sensation only the tongue can perceive. Furthermore, astringency, metallic taste, alkalinity, and coolness are not fundamental tastes either. Astringency, represented by tannins in tea, has an astringent effect on the skin. High concentrations like those found in astringent persimmons are extremely unpleasant, but a moderate concentration, like that found in tea, is quite pleasant.

Metallic taste is a flavor produced by metal ions or a weak electric current. Alkaline taste is a taste when the pH value is above 8, indicating a slightly alkaline environment; in Japan, it's also described as "fuss flavor." Cooling taste refers to the flavors of foods like mint and carbonated drinks. When choosing food, people usually look at the color and freshness first before deciding whether to buy. Seeing beautifully presented dishes immediately stimulates your appetite, especially Japanese cuisine, which can be described as "eating with your eyes."

Japanese cuisine is typically served in beautifully shaped tableware, emphasizing artistic presentation and rich coloring of ingredients. It can be said that the color and shape of food are crucial factors in judging its deliciousness. Our appetite is stimulated when we see something appealing; this is an instinct that doesn't change with cultural background. When strawberries are heated to make strawberry jam, their red color fades, turning into a pale brown. This pale brown strawberry jam is less appetizing than the translucent, ruby-red variety.

Colors can stimulate appetite, while others can reduce it. Generally, warm, glossy colors are more appetizing, with orange being the most appealing, followed by red and yellow. Conversely, neutral colors like yellow-green and purple are considered to reduce appetite. Furthermore, people have a strong association with the inherent colors of food, linking colors to food, and even its taste and aroma.