When I was a boy scout, one of our occasional activities would be the blindfold taste test. Blindfolded and holding our noses, things like sugar, coffee and fruit juice would be placed on our tongue and we had to guess what they were.
The point of the exercise was to demonstrate the importance of sight and smell to the taste experience, and also the way that our tongue has areas that sense the four basic tastes – bitter, sour, salt and sweet.
But it was a waste of our time because our understanding of taste was wrong in two fundamental ways.
First, the idea that different areas of the tongue can only sense one of the four basic tastes. This was based on the ‘tongue map’ published by Harvard psychologist, Edwin Boring, but he had based this on German research published in 1901 which he had mistranslated, missing out the vital word relative sensitivity.
In fact, our taste buds can detect all tastes more or less equally, but the record wasn’t put straight until 1974 when another American scientist, Virginia Collings, revisited the original theory.
There are at least five, the fifth being the meaty taste of protein in savoury foods such as bacon, cheese, soy sauce and Marmite. (Vegemite in Australia or Cerovis in Switzerland)
Kikunae Ikeda was a chemist at Tokyo University and he identified the taste that he called Umani in 1908 from a substance which he first derived from seaweed. But this fifth taste wasn’t confirmed until 2000 when researchers discovered protein receptors on the tongue.
The word Umani is derived from ‘umai’, meaning ‘tasty’ in Japanese and its key component is monosodium glutamate. Ikeda shrewdly sold his recipe to the Ajinomoto Company which today controls a third of the global market for synthetic MSG.
Prof Ikeda is recognised as one of Japan’s ten greatest inventors, but his seasoning gift to the world has been unfairly blamed for all sorts of illnesses, even though every investigation has given it a clean bill of health.
The idea that MSG was bad for you started in 1968 with ‘Chinese Restaurant Syndrome’ coined by Dr Robert Ho Man Kwok when he saw a number of patients complaining of palpitations and numbness after eating a large Chinese meal.
He blamed MSG, but later research showed that to cause such symptoms would require a level of MSG that would make the food completely inedible.
Glutamate occurs naturally in almost all foodstuff and is particularly high in parmesan cheese and tomato juice. Our own bodies produce 40 grams of the stuff every day and human breast milk contains both glutamate and sugar.
In degrees of threat to health on our dinner tables, salt is by far the most dangerous seasoning.