Scientists Make The Case For A 6th Taste — But It's Less Than Tasty
To the ranks of sweet, salty, sour, bitter and umami, researchers say they are ready to add a sixth taste — and its name is, well, a mouthful: "oleogustus."
Announced in the journal Chemical Senses last month, oleogustus is Latin for "a taste for fat."
"It is a sensation one would get from eating oxidized oil," explains Rick Mattes, a professor of nutrition science at Purdue University and one of the study authors.
Now, as we reported earlier this year, scientists have been trying to make the case for fat as a sixth taste for a while now. To qualify as a primary taste, a flavor needs to have a unique chemical signature and trigger specific receptors on our taste buds. When it comes to fat, scientists know the chemical stimuli (fatty acids), and previous research has shown that people have fat receptors in our mouths. But the definition of a primary taste also requires that people be able to distinguish the taste — which has been a sticking point.
That's partly because when people think of the taste of fat, they tend to conjure its mouthfeel — which is the result of triglycerides, Mattes says. "That gives the richness, the creaminess, viscosity and so on," he tells NPR's Rachel Martin.
Triglycerides are the overwhelming source of fat in our diet, Mattes explains. "But that is not the taste part," he says. "The taste part is when we cleave off part of that triglyceride, the fatty acid part." And once it's been cleaved off, the taste that remains is not exactly pleasant.
Mattes and his colleagues had 28 tasters sample lookalike mixtures with different tastes. They found that more than half of the people in their study were able to distinguish fatty acids from the other tastes.
Found in high concentrations in rancid foods, oleogustus actually operates as a protective mechanism of sorts — offering a warning sign to stop eating whatever it is one is tasting. In this respect, it's a bit like bitterness.
But Mattes is careful to offer a caveat.
"At very low concentrations, it may — we don't know this yet — but it may have exactly the opposite effect, the same way bitter stimuli, if you put it just in a glass of water, almost everybody would say it's unpleasant. But in the right context, bitterness adds to the overall appeal of chocolate, of coffee, of wine, many of the foods that we enjoy."
For the most part, though, oleogustus remains something of a paradox: fatty, but still not delicious. It may be tough to wrap your mind around the idea that fatty acids do not equal fatty goodness, but most in the food industry already have, Mattes says.
"The food industry goes to great lengths to keep concentrations of these fatty acids below detection, because they are unpleasant," he says.
9(MDE1MTIxMDg0MDE0MDQ3NTY3MzkzMzY1NA001))
Transcript
RACHEL MARTIN, HOST:
Listeners, we have a news bulletin for you now. Your attention, please, there is a new taste. Of course, we already know about sweet, salty, sour, bitter, even umami. But the newest one, the sixth one announced in a scientific journal last month, is called oleogustus. It's Latin for, a taste for fat. Rick Mattes is a distinguished professor of nutrition science at Purdue University. He was on the team that made the discovery. He joins me now. Hey, Rick, thanks for being with us.
RICK MATTES: Pleasure.
MARTIN: So what does it taste like?
MATTES: It tastes like oleogustus.
(LAUGHTER)
MARTIN: Delicious (laughter).
MATTES: Right. It is a sensation one would get from eating oxidized oil.
MARTIN: (Laughter).
MATTES: It is an unpleasant sensation. I know the initial expectation when we talk about fat is that it would be pleasant. The form of fat that gives the properties we enjoy is called triglyceride. That's the overwhelming source of fat in the diet and, in fact, in our bodies as well. But that really provides a mouth feel. That gives the richness, the creaminess, viscosity and so on. But that is not the taste part. The taste part is when we cleave off part of that triglyceride, the fatty acid part. And that is more of a warning signal. We find high concentrations of that in rancid foods.
MARTIN: Oh.
MATTES: And so it's really a signal that you should probably not consume this item, that it's unwholesome. Yes.
MARTIN: You're telling me that this fatty acid, this new taste, it's a protective mechanism of sorts designed to tell my body, stop eating this thing.
MATTES: It's much more like bitterness than sweetness, for example. Now, having said that, there is another caveat to this. At high concentrations, it would be aversive. But at very low concentrations, it may - we don't know this yet - but it may have exactly the opposite effect, the same way bitter stimuli, if you put it just in a glass of water, almost everybody would say it's unpleasant. But in the right context, bitterness adds to the overall appeal of chocolate, of coffee, of wine, many of the foods that we enjoy.
MARTIN: Is there any food that will generate this taste?
MATTES: Well, to give you an example, olive oil - if the concentration of the fatty acid rises above 3.3 percent in an olive oil, it's no longer considered edible. The food industry goes to great lengths to keep concentrations of these fatty acids below detection because they are unpleasant.
MARTIN: Do not eat this. It is not delicious. It's fatty, but necessarily delicious, which to me just, like, blows my brain because how can something be fatty and not delicious? But I digress. Rick Mattes is a professor of nutrition science at Purdue University. Thanks so much for talking with us about this, Rick.
MATTES: It's been my pleasure. Thank you. Transcript provided by NPR, Copyright NPR.
300x250 Ad
300x250 Ad