I’ve long suspected, based on intuition (which is often worth exactly nothing), that the standard taste model is wrong. The standard taste model claims that there are only 5 basic tastes: salt, sour, sweet, bitter and umami. Umami was just admitted into the pantheon by Western science a few years ago. Everything else we experience as taste is a function of smell according this model. The difference between a tomato and cheese aside from basic tastes is a matter of smell (putting aside texture of course). That has always struck me as implausible.
To test the sixth-taste theory, Dr Lim and her team dissolved different levels of carbohydrates in liquid solutions and gave them to 22 participants who were asked to rate how each tasted.
“They called the taste ‘starchy’,” Dr Lim said.
Previously, many scientists believed that humans could only taste the sugar in carbohydrates, as enzymes in our saliva break starch molecules into simple sugars, leaving a sweet taste in our mouths.
But even when volunteers were given a compound to block the saliva enzyme and sweet receptors, they were still able to taste the starch – which suggests humans can pick up on a starchy flavour before it has been broken down into sugar. Thus far there is no evidence of taste receptors for starch on the tongue so this is not a done deal. But it joins a long list of other sensations–of carbonation, a metallic flavor, and amino acids as well as kokumi, a flavor some describe as hearty—that scientists are investigating as basic tastes.
It would seem the standard model of taste is increasingly under threat.