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Figuring Out Flavor

From Winter 2012
Using “flavoromics” and a new state-of-the-art flavor lab, food scientists at the University of Minnesota are collaborating with food companies to solve flavor challenges.
By Greg Breining
Illustration by Michael Sloan

Thank goodness we don’t have to understand flavor to enjoy it. The simple pleasure of a morning cup of coffee begins as hundreds of compounds coat our tongue and trigger any of our 10,000 taste buds. As steam rises from the surface of the coffee and wafts through our nostrils or up the “back door” of our throat into our nasal passages, more than 800 volatile compounds excite our olfactory receptors.

“When you think about food, you should think about tremendous complexity—an infinite number of molecules,” says Devin Peterson, associate professor of food science and nutrition in the College of Food, Agricultural and Natural Resource Sciences at the University of Minnesota and co-director of its new Flavor Research Education Center. Indeed, foods have more than 7,100 volatile compounds that may affect smell and hundreds or thousands more that trigger taste, creating the mysterious characteristic we call flavor. Identifying the compounds that create flavor, Peterson says, is “a huge analytical nightmare.”

To solve the riddle of flavor with new analytical tools and research, food scientists at the University recently established the one-of-its-kind Flavor Center. Nearly a dozen “gold” sponsors, contributing $25,000 a year, form a consortium that will collaborate with the center to set a research agenda to address problems common to numerous food industry companies.

“The opportunity here is to focus on the key questions, the things we don’t know,” says Gordon Smith, vice president and research fellow at ConAgra Foods, one of the center’s gold sponsors. “It’s really kind of a cool idea: The insights are available to all, yet the specific applications of those insights can be very company specific. That’s why it works.”

Gary Reineccius (back) and Devin Peterson are co-directors of the Flavor Research and Education Center. 
“Flavor is exceedingly important to the food industry,” says Gary Reineccius, head of the Department of Food Science and Nutrition and co-director of the Flavor Center. “That is what largely determines people’s food choice—what they like. If something doesn’t taste good, a few people will hold their nose and eat it, but not many. And so it’s just extremely valuable to the industry.”

A lot is riding on the new center—not only better-tasting processed and convenience foods, but also more appealing healthful foods that might cut obesity and lead to better nutrition. With industry contributions, the Flavor Center will be able to conduct cutting-edge research while supporting and educating graduate students.

The Flavor Center opened in August. Reineccius and Peterson are still winnowing the suggestions of the consortium to three research projects for the year. But some of their work, and that of others at the center, suggests the kind of research they will be doing.

Peterson, for example, has recently tackled the problem of making whole grains more palatable. “Foods can be very healthy, but if they aren’t consumed, they have no health impact,” he says. Indeed, that describes the way many consumers respond to whole grain products. Peterson analyzed the compounds that form in the making and baking of whole grain foods, laboriously isolating hundreds of compounds to try to identify the ones that contribute to the bitter taste many people perceive. By identifying the compounds and how they form, Peterson anticipates that companies can change their recipes to prevent the compounds from forming. Says Reineccius, “It’s a nice example of what we should be doing.”

 Training for Taste
Zata Vickers, a University of Minnesota professor of food science and nutrition, characterizes flavors the old-fashioned way, with trained tasters. 

Flavor Center Sponsors
As of fall 2011, the Flavor Research and Education Center had 13 food industry sponsors. Gold sponsors contribute $25,000 a year; maroon sponsors contribute $15,000. For more information, visit
Gold Sponsors
ConAgra Foods
General Mills
Robertet Flavors
The Schwan Food Company

Maroon Sponsors
Another project shows the kind of highly specialized analysis of which the Flavor Center is capable. Jean-Paul Schirle-Keller, a full-time researcher at the center, was contracted in 2006 by Hormel Foods, which has a long relationship with the University and Reineccius. Based in Austin, Minnesota, Hormel was in a dispute with the city of Sparta, Wisconsin, over the construction of an ethanol plant. The company was concerned that air pollution from the plant would adulterate the products of its nearby dairy protein processing unit.

To find out, Schirle-Keller built a scale model of the processing plant and introduced minute concentrations of the compounds released by a typical corn-based ethanol plant. The compounds were marked with radioactive isotopes to ensure they were the compounds Schirle-Keller had introduced and not compounds formed elsewhere in the process. “The results were staggering,” he says. “An extremely small amount of compound in the air would react with those proteins.” In the end, Hormel prevailed and the ethanol plant wasn’t built.

But of all the analytical tools at the center’s disposal, Reineccius is most excited by a new process he has developed and dubbed “flavoromics.”

Because flavor is complicated, flavor science has been reductionist—breaking foods down into individual compounds and identifying the “targets” responsible for individual effects, such as a bitter taste. “The big problem we face in the flavor business is that when something isn’t right, we just don’t know why it isn’t right,” says Reineccius. “We empirically approach it—try this, try that, try that. Sometimes it works and sometimes it doesn’t.”

For example, the compounds that make up strawberry flavor don’t actually taste like strawberry until they are mixed with sugar and acid, which, by themselves, don’t taste anything like strawberries. Likewise, a chemical in oak-aged wines inhibits our perception of fruitiness—even though that chemical has no flavor of its own. In either case, ascertaining which chemicals are responsible for which flavor sensation by separating and testing compounds individually would be extremely difficult.

“The underlying basis for all of our analyses has been evaluating one thing at a time, out of context, out of the food,” says Reineccius. “We assumed there were no interactions whatsoever. No sensory scientist will accept that. And yet we haven’t had any other tools, any other way to approach this. We can’t deal with 1,000 chemicals.”

But then came flavoromics, a method to analyze compounds not one at a time, but all at once. Reineccius’s breakthrough came several years ago, when he chaired a search committee for a researcher in metabolomics. Simply put, metabolomics is an emerging biological research method that characterizes the small-molecule metabolites, byproducts of metabolism, to provide insights into physiological and pathological states of an organism. After sitting through several meetings and presentations on the arcane subject, Reineccius saw an opportunity. “The whole medical profession is developing new tools, techniques, and statistics,” he recalls thinking. “I’m going to take it and use it for flavor!” As it happened, Reineccius had a Ph.D. student conversant in the new field. “It just kind of came together.”

Flavoromics is essentially high throughput data collection. Using gas or liquid chromatography, researchers separate and identify thousands of compounds in many kinds of foods. Then, through statistical analysis, they can correlate how varying amounts of these compounds in different samples correspond to tasters’ perceptions of flavor.

“We use statistics to show certain chemicals are linked to, let’s say, cooked flavor in milk or cooked flavor in jam,” says Reineccius. “You run 500 different jams, they range greatly in cooked flavor, and I’ll be darned, we’ve got this group of chemicals that we can pick out statistically that moves with people’s judgment of cooked flavor.”

By moving beyond the one-compound, one-flavor-at-a-time approach, flavoromics presents a powerful analytical tool to tell food companies more about the flavors of their products than they every knew before. “This would give them a good foundation to address any flavor issues in their product,” says Reineccius. “This is a perfect example of . . . some fundamental work that benefits potentially all.”

Reineccius had been thinking of a flavor center for at least seven years, he says. The primary reason? Money. Federal funding for flavor science has stagnated. Reineccius was eager to build the facilities needed for such research—not only for his own pursuits, but also for his students and the University.

In 2009 Reineccius hired Peterson, who earned his doctorate in food flavor and related chemistry at the University of Minnesota, away from Penn State. He gave Peterson the task of helping to figure out how a flavor center might work.
Peterson’s first order of business was to build a top-flight lab. Today, the Flavor Center consists of three labs. The first is a prep lab with hoods, reactors, and the other equipment. The second room is a taste lab, where foods and other substances are separated into constituent parts. The third is the analytical lab where gas and liquid chromatography detect a dazzling variety of substances and potential stimuli in complex mixtures. Says Peterson: “My mission has been to really build my analytical capability.” He has wrangled loans of equipment from manufacturers that are eager to have their instruments used in groundbreaking new research. “Bar none it is probably the most technically advanced analytical center in the country,” says Peterson. “The amount of analytical horsepower we have in that lab is—there’s not a lab in food science I can think of that can even come close.”

Next was taking on the conceptual and marketing challenge: how to recruit sponsors by offering something of value—and then deliver. After studying other research center models around the country, Peterson and Reineccius decided they would have to solicit suggestions for research from their sponsors and select projects with broad appeal and applicability. The Flavor Center generally would not prescribe specific remedies for specific companies but would address problems common to all or many.

Reineccius and Peterson have recruited nearly a dozen companies as gold members at $25,000 a year, including food giants such as Kraft, Nestlé, and PepsiCo. Companies that join as maroon members contribute $15,000 a year. The money will buy supplies, cover maintenance, and pay salaries (though not those of Reineccius and Peterson, who are paid by the University).

Sponsoring a relatively small-budget flavor center makes sense even for multinational companies with their own large research divisions. John Scire, senior vice-president for Robertet Flavors, a multinational perfumery and food and beverage flavor company and one of the initial gold sponsors, says his company was eager to support the Flavor Center when it learned of the plan. “We thought it was an excellent idea because it doesn’t really exist in this format,” says Scire. “Their broad stroke is that there are going to be a lot of projects, different ideas, and resources from a fundamental perspective. These can offer a lot to various members. Especially today, no company can conduct all their own research.”

Gordon Smith of ConAgra says part of his job is to find ways to make use of university research and talents. ConAgra also has an interest in suggesting the kind of research that would find an immediate application. “The center is interesting for three reasons,” he says. “It allows us to understand who the best and brightest students are. It allows us to talk to academics about what we believe the students should be educated in when it comes to flavor and food chemistry. And it helps us integrate the research—either the consortium research or research that is funded through other sources—to ensure that the research that is being done has a meaningful home in the [applied] world.

“There’s a ton of science that needs to be done that hasn’t been done,” Smith continues. “Part of the role of the University is basic understanding. Their responsibility is understanding why things work and how things work. The companies are much better suited to execute, to transform that knowledge to consumer benefit, because we know our processes and we know our products and we know our consumer better than any academic ever would. That’s the reason consortiums work. It’s not just my money, but it’s my money times 10, or however many members you have. You start to get some critical mass. That’s what provides value.”

But the greatest importance of the Flavor Center is to the University itself. Even with federal research money scarce, by harnessing the contributions of large food companies, the Flavor Center provides an opportunity to build facilities, train graduate students, and continue research.

“Our job is to educate kids,” says Reineccius. “That’s why we’re here—to educate undergrads, to educate graduate students. And where do we get money to do this? With funding decreasing, we need to find places to get support so we can give our kids an education. Without that money they don’t get it. So here’s a place where I believe we can have an impact.” 

Greg Breining (B.A. ’74) is a St. Paul–based freelance writer.


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