In a study published in Chemical Senses, researchers from Purdue University posit that fat should be considered the sixth taste and can be called oleogustus. “Most of the fat we eat is in the form of triglycerides, which are molecules comprised of three fatty acids,” said Richard D. Mattes, distinguished professor of nutrition science. “Triglycerides often impart appealing textures to foods like creaminess. However, triglycerides are not a taste stimulus. Fatty acids that are cleaved off the triglyceride in the food or during chewing in the mouth stimulate the sensation of fat.”
The taste component of fat is often described as bitter or sour because it is unpleasant, but new evidence reveals fatty acids evoke a unique sensation satisfying another element of the criteria for what constitutes a basic taste, just like sweet, sour, salty, bitter, and umami. According to the researchers, by building a lexicon around fat and understanding its identity as a taste, it could help the food industry develop better-tasting products and, with more research, help clinicians and public health educators better understand the health implications of oral fat exposure.
The researchers proposed “oleogustus” as a way to refer to the sensation. “Oleo” is a Latin root word for oily or fatty and “gustus” refers to taste. Mattes said the taste of fat should not be confused with the feel of fat, which is often described as creamy or smooth.
Because there are no familiar words to ask people to use to describe the taste of fat, the 102 study participants were given multiple cups of solutions, each containing a compound that tastes salty, sweet, umami, bitter, sour, or fatty. The participants were asked to sort the solutions into groups based on which had similar taste qualities. Odor, texture, and appearance were all controlled.
The panelists easily segregated sweet, salty, and sour samples confirming they understood the task. Initially, the fatty samples were grouped with bitter because bitter is the vernacular descriptor for unpleasant taste sensations. However, when asked to sort samples including bitter, umami, and fatty stimuli, panelists grouped the fatty acids together and separately from the other samples.
