KOKUMI – A TASTE ENHANCER

At Kitchen Theory we are always interested in discovering new ideas related to the senses, the latest of which we were made aware of by Michael Booth in a simple little tweet mentioning ‘Kokumi’. This led to an immediate search which much to our surprise we realised Kokumi turned out to be a topic closely related to one we were already looking into (natural yeast, nutritional yeast and yeast extracts).

So what is Kokumi? 

A simple search online will reveal a multitude of definitions for the term itself, including;  heartiness, mouthfulness, rich taste, deliciousness and yummy. The literal  translation from Japanese is: rich (koku) taste (mi). However as with Umami (or any of the other tastes) a simple one word definition does very little to actually convey what this tastes actually is, and how it effects our perception of different foods.

From reading around about Kokumi it is clear to see that there is still a lot of work to be done in order to paint a comprehensive picture. What is known so far is that Kokumi are flavour enhancement compounds which supplement, enhance, or modify the original taste and/or aroma of a food but do not have a characteristic taste or aroma of their own.

So far researchers have concluded that Kokumi doesn’t actually have a taste in itself and that it enhances taste by triggering calcium receptors in the tongue. Kokumi compounds, such as calcium, protamine (found in milt), L-histidine (an amino acid) and glutathione (found in yeast extract) have now been shown to activate calcium-sensing channels in humans. In the January 2010  issue of the Journal of Biological Chemistry, Japanese researchers published the results of a study demonstrating that calcium channels on the tongue are the targets of kokumi compounds. In their 2012 paper entitled “Kokumi Substances, Enhancers of Basic Tastes, Induce Responses in Calcuim-Sensing Receptor Expressing Taste Cells” Japanese researchers at Institute for Innovation, Ajinomoto Co. reported that the calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Also that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances.

We came across a good description of Kokumi’s effects as described by Dr Harold McGee based on his experience at the Ajinomoto (the Japanese seasonings and food product company that discovered kokumi) research division in Kawasakito:

“Dr. Kumiko Ninomiya had kindly arranged for me to learn about the latest developments in research on ‘kokumi’, and then to taste its effects in five different foods. The substance was a peptide molecule composed of three particular amino acids (glutamine, valine, and glycine), which I was told is the most potent ‘kokumi’ substance known to date, and which was added in tiny quantities, from 2.5 to 20 parts per million of the food. (By comparison, salt and MSG have significant taste effects at around 1000 parts per million).

The flavors seemed amplified and balanced, as if the volume control and had been turned up and an equalizer turned on. They also seemed somehow to cling to my mouth–a tactile feeling–and to last longer before fading away. And the effects extended to aroma as well as taste, though I imagine indirectly through the taste effects.”

Ajinomoto are producing Kokumi using enzymatic synthesis (in a similar fashion to how they produce MSG). As of August 2014 Kokumi compound gamma-glutamyl has been approved as a food additive, now the plan is to produce a kokumi ‘taste/flavour enhancing’ powder!

In our search we also came across some interesting online resources for anyone wishing to do a little extra reading around the topic:

Online pdfentitled ‘Evaluation of Kokumi Taste of Japanese Soup Stock Materials Using Taste Sensors’

Biochemical Sensors: Chapter 8 ‘Investigation into the Kokumi Taste of Soup Stock Mineral’ (Google books)

Concept Makers: In Search of Kokumi (Alex Atala and Alvin Leung as guests experts on the Givaudan Chef’s Council)

DSM presentation on Kokumi byFrank Meijer

All the information for this article was sourced from the below links:

http://www.umamiinfo.com/2013/01/kokumi-experience-report-by-dr-harold-mcgee-1.php

http://www.forum.co.uk/pdf/Kokumi.pdf

http://www.thestar.com/life/food_wine/2010/10/28/after_umami_a_sixth_taste_is_discovered_kokumi.html

http://www.livescience.com/17782-sixth-taste-flavors.html