Beyond the Basic Five (Online Exclusive)

Despite the long-accepted view that there are five basic tastes, some scientists, including Michael Tordoff, a researcher at the Monell Chemical Senses Center in Philadelphia, find that viewpoint limiting.

“I think that there are many tastes,” says Tordoff. “The problem is that there is no really good definition of what a basic taste is.”

Tordoff, an expert on mineral tastes, includes calcium and phosphorous on his personal list of important tastes. He also notes that, for rodents at least, the catalog of basic tastes may well include starch. He points out that rodents have taste receptors for starch and prefer it over just about any other substance, including sugar.

Probably the highest-profile proposed addition to the pantheon of human basic tastes is fat. Purdue University nutrition science professor Richard Mattes and a team of researchers last year introduced the idea of fat as the sixth basic taste and suggested the name oleogustus to describe it. The name combines the Latin words for fat or oily (“oleo”) and taste (“gustus”).

Mattes recently discussed the concept in an IFT webinar titled “Is Fat Another Basic Taste?” as part of the Sensory Science Mythbusters series. Mattes said that the idea of fat as a primary taste is not completely new; in fact, ancient Greek philosopher Aristotle categorized “fatty” as a basic taste sensation. While Mattes acknowledged that there is no universally accepted definition of a basic taste, he took webinar participants through a series of criteria that he sees as key elements for categorizing a taste sensation as primary or basic and explained the ways that fat satisfies the criteria.

Mattes described the study that he and collaborators Cordelia Running and Bruce Craig conducted in which human sensory panelists were able to detect the taste sensation of nonesterified fatty acid in test solutions and identify its taste as distinct from the tastes of sweet, sour, salty, bitter, and umami. In the study, panelists were asked to sort solutions according to their taste qualities. Initially, they were able to identify the tastes of the sweet, salty, and sour samples, but they grouped the fatty samples with the bitter ones because bitter is the terminology that is typically used to describe unpleasant taste sensations. But when the panelists were asked to sort samples that delivered bitter, umami, and fatty taste stimuli, they were able to group the fatty acids separately.

“Fatty taste itself is not pleasant,” said Mattes in a discussion of the study around the time of its publication. “When concentrations of fatty acids are high in a food, it typically is rejected as would be the case when a food is rancid. In this instance, the fat taste sensation is a warning to not eat the item. At the same time, low concentrations of fatty acids in food may add to their appeal just like unpleasant bitter chemicals can enhance the pleasantness of foods like chocolate, coffee, and wine” (Purdue 2015).

Sensory scientist Jeannine Delwiche, creator of the Tasting Science website and a webinar copresenter with Mattes, said she believes that sticking with the notion that there are four or five basic tastes limits sensory research. “The problem with a basic taste model is that it brings a limitation when you conduct research,” says Delwiche, adding that working within that framework can result in the distortion of experimental data. “In a nutshell,” she emphasized, “taste is more complicated than is commonly recognized.”

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