There are five acknowledged tastes: sweet, sour, bitter, salty, and (slightly more controversially) umami. For awhile now, researchers have suggested the existence of a sixth taste: fat. Now, a new study has researchers saying they may have finally isolated it—and they’ve given it a name: oleogustus.
When we talk about a “taste” it’s generally accepted that taste itself is only one part of what we’re talking about—we’re also talking about the texture and feel of the food, and it’s in that area that the idea of fat as a taste is most easily accepted. Fat is pleasurable to eat, essentially because of what it does to the texture of the food—it makes it silkier, richer, and this, in turn, brings the other flavors of the food to a fullness they would never have otherwise.
But, if fat is to be acknowledged as one of the basic tastes, it must be distinct not just because of the textural changes it makes to other flavors—fat must be a new flavor itself, one that can be recognized in areas beyond texture.
In a new study from Purdue University published in Chemical Senses, researchers attempted to isolate it by stripping fat to its base element: nonesterified fatty acids, which they then mixed into solutions and gave to some unlucky test subjects to compare with solutions containing the other five basic tastes.
While there was some overlap with the solutions for sour and umami tastes, the majority of people were able to identify oleogustus as a taste distinct in itself, lending credence to the idea that it is, indeed, a sixth taste.
But if the researchers want us to accept the proposition that fat is a taste, they also want us to understand that it’s a particularly revolting one.
At various times throughout the paper, the flavor of fat is characterized as “unpalatable,” it is compared in content “to many fermented or rancid products”, and perhaps most harshly, “perceived primarily as irritating,”. What’s more, say the researchers, there’s something remarkably, and disappointingly, un-fatty about it:
Notably, the taste sensation elicited by long chain fatty acids is not wholly consistent with the expectations of “fattiness.” Given the clear unpleasantness of the sensation in isolation, and the incongruity with the term “fatty,” which has strong textural context, we propose a term term to describe the taste of the long chain NEFA.
So, while oleogustus may, indeed, be its own distinct taste, it may not be one that you want to re-sample on its own
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