Tackling the Science of Taste

Taste buds don’t get the attention they deserve, contends Robin Dando, an associate professor of food science and head of The Dando Taste Physiology Lab at Cornell University.

Understanding how our taste buds behave is the focus of his work. That’s important because with a better understanding of our taste buds’ full set of functions, it may be possible to create healthier foods with appealing sensory characteristics.

A taste bud is a tiny organ of around 50 to 150 taste receptor cells. Current research suggests that not only do taste buds communicate taste among themselves and the brain, but they also receive messages from other parts of the body. Taste buds contain receptors for hormones, including insulin and the satiety hormone leptin, Dando explains.

“The sorts of things that are pumping around our body and are linked with food intake, the receptors for those things are inside the taste buds,” he says. “That means that maybe they’re changing how food actually tastes to us when we consume it.”

Dando has a somewhat unusual background for a sensory specialist: physics. His undergraduate and doctoral degrees were in biological physics, and his master’s in a related field, nanotechnology. He did his postdoctoral work at the University of Miami’s medical school, where he investigated taste cells.

He joined Cornell 11 years ago to set up his own sensory lab, where he and his lab mates work on understanding food decisions—how we choose a food, how much of it we eat at a meal, and why we’ll pay more for some foods than others. “If we can understand those decisions, then maybe we can more effectively encourage people to make smarter decisions,” he says.

Carmen Moraru, professor and chair of the Department of Food Science at Cornell, was part of the search team for Dando’s position. He stood out among the job’s candidates, she says, because of his uncommon combination of traditional sensory science with a neuroscience approach.

“That brought a unique perspective because he was able to make those links between what happens at the taste bud level from a neuroscience perspective and the impact this might have on humans’ perception of taste, as well as metabolism,” she says.

Sweet Replacements

The sensory reward that sweetness delivers is among the areas Dando’s research team has explored. “Sugar has a bit of a bad name at the moment,” Dando observes. “Modern consumers are looking to get rid of added sugars in foods. But the problem is that things that taste sweet generally taste good too. We like how sweetness is experienced.”

Most of the sugar in food now is sucrose. Subtracting sucrose from food formulations often means turning to sweeteners that are considered natural like stevia and others. But they have their own problems, particularly strange, often metallic aftertastes, bitterness, and a lingering sweetness that is at odds with our expectations.

“We like our sweetness to pop right up and then pop right down again,” explains Dando. “If it continues to taste sweet to us 10 seconds, 20 seconds after we’ve taken a sip of something, we’re not totally comfortable with it [because] it doesn’t taste like the thing that it’s trying to mimic.”

Recently published research from Dando and co-author Margaux Mora, who was a doctoral student at the time the research was done, investigated the sensory qualities of a range of sweeteners that fall in the natural category. They blended seven different sweeteners with sucrose to see if they could find an optimal mix.

We like our sweetness to pop right up and then pop right down again.

“The motivation for trying to see how these sweeteners blend was to see if we could help reduce some of those [unpleasant] properties while still keeping some functionality,” Mora says.

That’s because sugar is also an important functional ingredient in many formulations, says Mora, who is now an associate scientist for global taste modulation applications at Ingredion. Sugar is important, for example, for browning and moisture retention in baked goods. It also plays a role in the freezing point depression and creamy texture of ice cream, as well as the development of ice crystals.

The replacement sweeteners—allulose, erythritol, Reb A, Reb D, Reb M, monk fruit, and thaumatin—were each blended with 50% sucrose and 75% sucrose. The blends were then sampled by 13 trained sensory panelists.

A blend of 50% sucrose kept sucrose’s sensory features while mitigating the off-flavors with allulose, erythritol, Reb D, and Reb M. But monk fruit, thaumatin, and Reb A still had odd aftertastes. Of all the sweeteners, allulose and erythritol were most like sucrose.

“We’re hoping that this could help inform a good level of sweetness or sugar replacement, even if we’re not doing 100% sugar replacement,” Mora says.

Recent research on erythritol has linked it to heart problems. However, Dando points out that erythritol is already present in the body and is “elevated in people who are having cardiac problems, so there is the potential for that study to have another explanation.”

The sucrose blend research builds on a previous review paper from Dando and Mora where they provided an overview of substitute sweeteners and their metabolic behaviors.

“Natural, synthetic, high potency, bulk, all of these are kind of grouped together as different alternative sweeteners,” says Mora. “And they really should be partitioned because they do function differently.”

They reviewed natural and synthetic sweeteners, including saccharin, aspartame, sucralose, honey, maple syrup, and monk fruit. They also conducted a consumer survey of 400 people to collect their opinions on sweeteners. Perhaps unsurprisingly, the more well-known a sweetener was, the higher rating it received, Mora explains.

In work that’s similar to his sweetener research, Dando has tackled another modern dietary problem: salt intake. He’s studied eaters’ reactions to salt replacements and whether consuming them changes their taste for savory foods.

“We might not be able to take all the salt or all of the sugar out of foods,” says Dando, but instead find a middle ground where they are reduced while keeping foods’ preferred tastes.

“Maybe that’s going to be a more effective treatment than getting almost all of the sugar or salt out of a food and then people not sticking to that treatment.”

More Exploration

Dando’s research interests are wide-ranging. He previously conducted a pilot project using virtual reality (VR). Sensory scientists know that context matters when we eat—the location, people nearby, sights, sounds, and smells. Dando wanted to see whether newer technologies could be used to add some of that context while maintaining the control of the traditional sensory booth.

“Where VR is useful is combining those two things,” Dando says. “You can still be in that booth with all of that control, but you can be experiencing through your other senses a little bit more of that real world.”

Dando continues to work on sweeteners with new research that follows up on the binary mixture approach. The next obvious step, he says, is to make more complex blends of several different sweeteners and see how close they can get to the sensory experience of sucrose. Dando expects results from that work to be published next year.

And, of course, continuing research to further uncover the secrets of our taste buds remains a focus. For example, when someone gains weight, explains Dando, their taste buds change. If someone gains a lot of weight, does that change the taste buds’ response to taste, and thereby prompt more eating? Dando’s lab is seeking answers.

“Maybe the taste bud has a more important role to play than people have in the past figured out,” he says.ft