Fat may be a sixth basic taste

Researchers at Purdue University asked volunteers to taste solutions of free fatty acids, the raw building blocks of fat released when it breaks down, and sort them, alongside samples of the established tastes, by how similar they seemed.

Cordelia Running's team found that participants grouped medium and long-chain fatty acids apart from sweet, sour, salty and bitter, with some overlap with umami, and proposed the name oleogustus for it. Shorter-chain fatty acids tasted somewhat sour, but as the chain length grew longer, the taste shifted into something participants agreed was its own separate sensation.

Because detecting free fatty acids directly, rather than just sensing the texture of whole fat, appears to involve its own candidate receptors, the finding reopened the question of how many basic tastes the tongue actually has. Not every sensory scientist accepts oleogustus as a true sixth taste rather than a variant of existing ones, and the debate over where to draw that line continues.

Fat might taste like something of its own.