Senses And Ingredients
What Is Umami? Glutamate In The Language Of Food
Umami is a basic taste quality associated with glutamate. Often described as savoury or broth-like, it connects ingredients as different as kombu, tomatoes and certain cheeses. Recognising it adds a distinct word beside sweetness, saltiness and aroma.
How We Prepare These Articles
What Does Umami Describe?
Sensory science places umami among the basic taste qualities, alongside sweet, sour, salty and bitter. Chilli heat belongs to a different kind of sensation. Descriptions such as meaty or broth-like help convey umami, but they do not require an animal ingredient: plant foods can contain compounds associated with the same taste.
Calling a dish delicious makes a judgment about the whole encounter. Umami names something more specific. It can appear together with a food's aroma, temperature, texture and other tastes. Treating it as another word for deliciousness would remove one of the useful distinctions the term makes possible.
Describing a tomato only as umami would also leave much out. In a hot sauce containing tomato, umami, the pepper’s pungency and the sauce’s aroma are different questions. Finding tomato in an ingredient list does not by itself establish the finished sauce’s umami intensity: one taste quality is not the ingredient’s whole portrait.
From Kombu To A Scientific Question
In 1908, the Japanese chemist Kikunae Ikeda connected glutamate with the distinctive taste of kombu broth. A familiar culinary experience became a chemical question: which substance could account for that taste? The discovery concerned identifying a quality within an existing preparation, rather than inventing a new dish.
Ikeda's paper 新調味料に就て appeared in 1909. The open extract from its later English rendering, published in Chemical Senses in 2002, proposes the name umami for a quality he distinguishes from four familiar tastes. The dates refer to different events: the research in 1908, the original publication in 1909 and the English rendering in 2002.
The interest of the story lies in the conversation between culinary language and a laboratory question. Kombu was the concrete material of the investigation. Umami became a taste concept extending beyond that material. A question beginning with one preparation acquired an identity that could be investigated across other foods.
Glutamate, Glutamic Acid And MSG
Glutamic acid is an amino acid. Glutamate refers to its ionised form; monosodium glutamate, or MSG, is its sodium salt. Umami therefore names a sensory quality, whereas MSG names a particular substance. The two words operate at different levels of description.
The form in which glutamate occurs in a food also matters. Glutamate incorporated within a protein and free glutamate do not describe the same sensory situation. Kurihara's review explains the relationship of free glutamate to umami and how protein breakdown can release it. A food's protein content alone consequently does not describe its umami intensity.
The FDA's examples of tomatoes and cheeses connect the chemistry with familiar ingredients. Considering those foods together shows how one taste quality can occur within very different aromas and textures. It does not establish that every tomato or every cheese has the same sensory profile.
How Nucleotides Change The Response
Two abbreviations recur beside glutamate in umami research: IMP and GMP. They refer to nucleotides associated with 5′-inosinate and 5′-guanylate. The umami response to glutamate together with these compounds can be stronger than their separate responses. Synergy is the research term for this relationship.
The receptor formed by the proteins T1R1 and T1R3 is an important part of the molecular question. Li and colleagues' study of human receptors reported that nucleotides could enhance the response to glutamate. Toda and colleagues subsequently used cell assays to investigate why human and mouse receptors do not show the same selectivity for different amino acids.
These experiments measure receptor responses under specified conditions. They do not measure a dish's entire flavour or how much someone will like it. A mechanism offers an explanation for a culinary relationship without promising an identical sensory outcome in every mixture. One compound's identity and the relationship between several compounds remain different questions.
Different Sensory Layers In One Ingredient
| Concept | What It Describes | Example Description |
|---|---|---|
| Umami | A basic taste quality | Broth-like taste |
| Aroma | Qualities perceived through smell | Herbal or fruity smell |
| Texture | Physical structure and feel in the mouth | Smooth or particulate |
| Pungency | A chemesthetic sensation | The burning sensation of chilli |
These distinctions name details within an experience that occurs as a whole. A sauce's umami quality and fruity aroma can share a sentence. Each helps describe the ingredient without having to explain the other. The resulting vocabulary leaves more of the food's character available to attention.
Sources And Further Reading
- NIDCD · How does the sense of taste work?
Reading area: Institutional explanation: basic tastes, smell and chemesthetic sensations within flavour.
Accessed:
- FDA · The identity and history of monosodium glutamate
Reading area: MSG's chemical identity, Ikeda's 1908 research and examples of glutamate in foods.
Accessed:
- Kikunae Ikeda · On a new seasoning, 1909
Reading area: Publication record and scan of Ikeda's original Japanese paper, 1909.
Accessed:
- Kikunae Ikeda · New Seasonings, English rendering, 2002
Reading area: The open extract of the 2002 English rendering: the proposed name umami.
Accessed:
- Kenzo Kurihara · Umami: taste, compounds and research history, 2015
Reading area: A 2015 review of free glutamate, IMP/GMP, umami history and receptor research.
Accessed:
- Toda and colleagues · Ligand specificity in the umami receptor, 2013
Reading area: A 2013 cell study of differing amino-acid selectivity in human and mouse T1R1/T1R3 receptors.
Accessed:
- Li and colleagues · Human receptors for sweet and umami taste, 2002
Reading area: Abstract of a 2002 human-receptor study: glutamate responses and enhancement by nucleotides.
Accessed:
- NIDCD · The two routes of smell
Reading area: Institutional explanation of smell through the nostrils and the throat-to-nose route.
Accessed: