Scientists have identified a new taste receptor on the human tongue that could add to our understanding of why wines taste the way they do.

The finding, published in leading scientific journal Nature, supports the idea of a fifth taste, called umami by the Japanese, to accompany bitter, salty, sweet and sour.

Umami, which translates as ‘savouriness’ or ‘deliciousness’, is the taste of amino acids like monosodium glutamate (MSG). Amino acids are also present in wine at appreciable levels.

Umami is the elusive ‘fifth taste’ whose presence until now has been doubted by scientists. There has been debate about whether it might be a combination of other tastes rather than a specific taste in its own right.

Now an amino acid receptor – a taste cell in the tongue – has been discovered by American academics Charles Zuker and Nick Ryber. This receptor – which can recognise amino acids – appears to settle the argument.

A key question now is whether amino acids affect the taste of wine, which typically contains 1-4 grams per litre of these compounds. Zuker reckons these levels of amino acids would ‘robustly’ activate the umami receptor.

‘Amino acids clearly play a role in the taste of wine,’ he told ‘But because the perception of wine reflects the interaction of so many tastes in such a complex mixture, we cannot assign a value to the contribution of the umami receptor versus the sweet, sour, bitter and salty receptors.’

Written by Jamie Goode5 March 2002