22/02/2015
Your tongue doubtless knows the difference between a high-fat food and the low-fat alternative. Full-fat ice cream and cream cheese feel silkier and more sumptuous. Burgers made with fatty meat are typically juicer than burgers made with lean meat.OK, so, we've long known fat gives food a desirable texture. But some scientists are now making the case that we should also think of fat as the sixth primary taste, along with sweet, salt, sour, bitter and umami.Early in February, researchers from Deakin University in Australia published a paper in the journal Flavour arguing that "the next 5 to 10 years should reveal, conclusively, whether fat can be classified as the sixth taste."So what would it take for fat to become an official taste?"Strictly speaking, taste is a chemical function," Russell Keast, a sensory scientist at Deakin and lead author of the paper, tells The Salt. He says that when a chemical substance – a salt or sugar crystal, for example — comes into contact with sensory cells in our mouths, it triggers a series of reactions. The cells in our mouths tell other nerve cells that they're perceiving something sweet or salty and those nerve cells eventually pass this information on to the brain.According to the paper, there are five criteria that need to be met to call something a primary taste. It starts with a chemical stimuli (like sugar or salt), which then trigger specific receptors on our taste buds. Then, there has to be a viable a pathway between these receptors and our brains, and we've got to be able to perceive and process the taste in the brain. And finally, this whole process has to trigger downstream effects in the body.When it comes to fat, scientists know what the stimuli are: fatty acids — the building blocks of oil, butter and lard. And scientists also know that we have taste receptors for these fatty acids in our mouths and intestines.But researchers have yet to pin down exact how our the receptors on our tongues signal the presence of fat to our brains, though they have some promising leads.And here's another place where thinking about fat as a taste gets interesting, and controversial: "When we eat something sweet, we have that instant perception of sweetness. With fatty acids, we don't have a conscious perception," Keast says.In his experiments, Keast says, people usually can't even describe what a solution with pure fatty acids tastes like. "They'll say they know it's different from water, but they don't know why," he says. "We …
