The 5th Taste

Discovered in Japan and now internationally recognized, umami has been under the global spotlight as the fifth basic taste with the others such as sweet, sour, salty and bitter. In 1908, Professor Kikunae Ikeda discovered glutamate as the umami substance in kombu. In 1913, Shintaro Kodama found inosinate to be responsible for the umami taste in dried bonito, and in 1957 Akira Kuninaka named guanylate as another umami substance. Even though umami compounds are commonly present in foods such as tomatoes and cheeses, it took time for them to be recognized internationally mainly because they were discovered by Japanese scientists.

Thanks to international umami symposia, more Western scientists are involved in the research on umami. This has led to a significant progress for umami to be generally accepted as the fifth basic taste. Now, it has become a common word in foreign languages as the Japanese cuisine enjoys an unprecedented popularity in many countries.

Market relevance

Our sense of sight, hearing, smell, touch and taste helps us form general judgments on the food we eat. The sense of taste, with the five basic or primary profiles, is however the most influential when it comes to determining how delicious food is.

Although there is no English word for it, umami is the savory taste that glutamate and nucleotides such as inosinate and guanylate impart. The subtle taste blends well with the other four tastes to enhance and round out the flavor of foods. It is found in tomatoes and fermented seasonings such as fermented fish sauces and pastes in Asia, and cheeses, anchovies and cured ham in western cuisine.

Discovery of umami

Ever since a German physiologist proposed his theory at the beginning of the 19th century that there were four basic tastes - sweet, sour, salty and bitter - it had long been believed without scientific evidence that there was no other taste. However, in 1908 Professor Kikunae Ikeda of Tokyo Imperial University discovered another taste that was distinct from the four.

To connect chemistry and the senses, Professor Ikeda discovered glutamate as key to the taste of the Japanese seaweed soup stock kombu dashi. He named the distinct taste umami and concluded in his thesis that it was also a basic taste. And in his presentation at the 8th International Congress of Applied Chemistry in 1912, he said: "An attentive taster will find something common in the complicated taste of asparagus, tomatoes, cheese and meat that is quite distinctive and does not fall into any of the traditional categories of taste."

Umami use in Southeast Asia

Umami is a savory taste imparted by substances such as glutamate, inosinate and guanylate. While glutamate is naturally present in most foods, inosinate is found in meats and fish such as dried bonito, and guanylate is abundant in plant foods such as dried shiitake mushrooms. The level of umami increases significantly during the fermentation process of food such as cheese and cured ham. The can also be found in pork and beef.

A wide variety of umami-rich foods are used in cuisines globally. Fermented fish sauce and paste made from fish or small shrimps fermented bean products are common in Asia. In the 15th century, rice was cultivated in most Asian countries as a staple food. Since the quality of protein in rice is considered better than wheat as it contains a balanced proportion of essential amino acids, it is seen as a source of protein. Today, unflavored steamed rice is usually eaten with a variety nutritionally balanced fermented foods, which combines salt and umami to provide a harmony in taste. Fermented foods made from either fermented fish or shrimps in Southeast Asia include nam pla (Thailand), nuoc mam (Vietnam), terasi (Indonesia), ngapi (Myanmar) and bagoong (the Philippines).

• A study of two sauces

In the early 1980s, Japanese dietary histologist Professor Ishige conducted a large-scale survey on 300 kinds of fermented fish and shrimp products in 13 Asian countries. He found that the fermented products are consumed in the same way the West use salt and seasonings. Fermented fish or shrimp products are made by first adding large amounts of salt to fresh fish or shrimps that are sunned for at least three months. After fermentation, the protein in fish decomposes into free amino acids, which are mixed with salt to become important taste substances in fermented foods.

His analysis of the amino acid content in fermented products showed glutamate to be the most abundant amino acid. A taste comparison between the fish and soy sauces showed that the amount of salt in fish sauce (at 26%) is higher than that of soy sauce (at 17%) by 9%, while the amino acid content in fish and soy sauce is almost the same at 5%. Of the 20 kinds of the amino acids found in both sauces, the glutamate content is at 0.8% for the sauces. Thus, salt is found to be the main differentiator of the fish and soy sauces. Fish sauce adds a salty and umami taste to dishes and is commonly used Southeast Asian cuisine as a seasoning.

Professor Ishige found that the grade of fish sauce is determined by its cost, which is in turn dependent on the glutamate content. The most expensive sauce ('first grade') was found to have the highest content of glutamate and functions today as a taste enhancer in Southeast Asian cuisine.

Fermented foods in China

Fermented foods such as douchi and chi, which are fermented black foods based on soya are used in the Chinese cooking. They are semi-dried granular condiments that are found to be linked to recent archeological findings - burial gifts unearthed in Maoutaikanabo (ancient tomb) excavation in Hunan, Changsha, are considered by experts to date back to the second century BC. They include food items and among them was 14g of douchi-jiang (ginger-added douchi). Made from grains, jiang (the word for 'sauce' in Mandarin) is an important fermented condiment in China. Based on historical records, jiang was traditionally made from meat or fish. It was prepared by pickling finely chopped meat or fish with salt and yeast in a sealed jar. It was common to prepare jiang prepared from grains in the first century BC. Today, it is made using bean paste and the three variations are namely Huang jiang, Tianmian jiang and Douban jiang. The second and third versions are commonly used for Peking duck dishes and in Sichuan cuisine.

Soy, fish sauces (called yulu) and other fermented products are also widely used in Chinese cuisine. These salt-based condiments generate the umami and salty tastes, imparting a complex gustatory spectrum acquired during the fermentation process.

www.umamiinfo.com