What is umami - Fifth taste in the global spotlight

Umami is the fifth taste, joining sweet, sour, salty and bitter. These are unique tastes that cannot be created by mixing other tastes, and are known as the basic, or primary tastes. Umami is a general term used mainly for substances combining the amino acid glutamate, and/or the nucleotides inosinate and guanylate, with minerals such as sodium and potassium.

Whether something tastes good or not is a comprehensive yet subjective evaluation determined by elements such as taste, aroma, texture and temperature, besides other factors such as appearance, color and shape, as well as one’s physical condition, surrounding environment, cultural background, and previous experiences. Of these various elements, umami in balance with the other basic tastes (sweet, sour, salty, and bitter) plays an important role in determining the deliciousness of a dish.

For human beings, being able to distinguish the five basic tastes is an indispensable survival skill, because it allows us to avoid risky foods and obtain nutrients safely. By detecting the sour taste of organic acids in unripe fruit or rotting food, or the bitterness of alkaloids, for example, our tongue enables us to avoid danger. In contrast, when we detect the sweetness of sugars that serve as our energy source, or the saltiness of minerals necessary to maintain the balance of body fluids, we actively consume them. Umami meanwhile serves as a signal to the body that we have consumed protein. Sensing umami triggers the secretion of saliva and digestive juices, facilitating the smooth digestion of protein.

The main components of umami are glutamate, inosinate and guanylate. Glutamate is found in a variety of foods including meat, fish and vegetables. Inosinate is found in generous quantities in animal-based foods such as meat and fish, while large amounts of guanylate can be found in dried mushroom products such as dried shiitake. We also know that the umami component of food increases as a result of processing such as ripening and fermentation. Many traditional foodstuffs from around the world, such as soy sauce and other fermented condiments made from grain, fish sauces such as Thailand’s nam pla and nuoc mam from Vietnam, and cheeses are excellent sources of umami.

The main umami substances are glutamate, inosinate and guanylate, and it has been scientifically proven that umami is sensed far more strongly when these are present not individually, but when glutamate is combined with inosinate or guanylate. This is referred to as umami synergy. Yet people have been capitalizing on umami synergy for centuries, long before this effect was scientifically proven. All over the world, in dishes from soups combining glutamate-rich vegetables and inosinate-rich meat and fish, to the tang of Chinese cuisine extracted from chicken or pork bones and green onions, to Japanese dashi made from kombu (high in glutamate) and katsuobushi (high in inosinate), people have acquired an empirical understanding of umami synergy and applied that knowledge to cooking.

The strength of the umami synergy between glutamate and inosinate varies according to the ratios of each. When solutions containing slightly varying proportions of glutamate and inosinate were used to perform a sensory evaluation, umami was found to be most powerful with a glutamate to inosinate ratio of exactly 1:1. This proportion was deemed 7 to 8 times the intensity of tasting either glutamate or inosinate in isolation. An analysis of the ichiban (primary) dashi used at one venerable Japanese restaurant revealed the glutamate/inosinate ratio to be exactly 1:1, suggesting that top restaurants know from experience the optimal proportions for greatest umami.

Adelicate taste. A mild, subtle taste. A taste that spreads across the tongue, coating it completely. A persistent, lingering taste. A mouthwatering sensation. This is how chefs who have experienced and recognized umami describe its characteristics. Let us take a look at three properties of umami.

Throughout history, human beings have created various seasonings and condiments to improve the palatability of food. Salt has been a familiar flavor-enhancer for thousands of years. Foods such as sugar and vinegar have also been known since ancient times. This is why we can all readily imagine sweet, sour and salty tastes. Umami too is contained in a variety of foodstuffs, and is familiar to us from the taste of traditional foods such as soy sauce, miso and cheese. However, it is only around a century ago that umami was discovered as a basic taste, and monosodium glutamate invented and launched as an umami seasoning.

There were long thought to be just four basic tastes: sweet, sour, salty and bitter. Then a scientist in Japan - Professor Kikunae Ikeda of Tokyo Imperial University (now the University of Tokyo) - noticed the presence of a taste that did not fit into any of these categories. Professor Ikeda discovered the main taste component in kombu dashi (broth or stock) to be glutamate, and dubbing it “umami,” penned an academic paper explaining the existence of umami as one of the basic tastes. Following in Professor Ikeda’s footsteps, other Japanese scientists discovered the umami substances inosinate and guanylate.

Throughout the Ancient Roman Empire, fermented fish sauces called garum and liquamen were used as seasonings. These ingredients were equally as important as wine and olive oil. They were produced in the same way as the fermented condiments of South East Asia, with fish such as sardines and mackerels being salted and fermented. In particular, the amber-colored garum extracted first from the fermentation process was most highly prized. The famous ‘Apecius Cookbook’ of Ancient Rome contains many recipes where, in times when there was no sugar or salt, garum was frequently used. One could say that garum was prized as a condiment which combined umami and saltiness. The use of garum died out along with the Roman Empire, however anchovy paste and sauce can be seen as its modern counterpart.

Different types of fermented seasoning can be found throughout the world. Fish sauces such as Num Pla in Thailand and Nuoc Mum in Vietnam, along with a range of fermented products typified by miso and soy sauce, have long been used and appreciated in Asian countries. Fermented condiments are made by adding salt to fish, beans, grains, etc., and allowing them to ferment. During the fermentation process, proteins are broken down into their constituent amino acids, and a condiment which contains high quantities of glutamate is produced. Particularly in Asian countries with a tradition of wet rice cultivation, daily cooking which does not include the addition of seasonings is unimaginable. This is a particular characteristic of countries where white rice, vegetables and fish form the staple diet. Rice based diets and simple forms of umami are very closely linked.

Recent years have seen a growing shift in the developed world toward fewer calories and animal fats, as people look to prevent lifestyle diseases and maintain good health. As part of this dietary trend, Japanese cuisine has enjoyed burgeoning popularity, thanks to its health properties. Rather than relying on animal fats, Japanese cooking uses the umami of dashi to highlight the intrinsic flavors of ingredients, and chefs from all over the world have started visiting Japan to study these cooking techniques. Learning how to make Japanese dashi, they master the use of umami as an alternative to animal fats before going on to develop their own approaches to umami-oriented cooking.