Tasteful Language
Perspectives On Line: The Magazine of the College of Agriculture and Life Sciences

NC State University

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Breaking down cheeses into chemical compounds, Drake extracts volatile components to assess aroma or flavor-contributing activity. (Photo by Becky Kirkland)





























"The beauty of these languages is
that they're very versatile."















































"Tasteful Language": In MaryAnne Drake's sensory lexicon of dairy foods, specific words denote flavor and connote chemistry --- and help to deliver the products consumers want. --- By Terri Leith

"Flavor is my big thing," says MaryAnne Drake (left), who links up words such as "nutty" with specific chemical references when describing the taste of cheese. (Photo by Becky Kirkland)

ornate letter I n June, Dr. MaryAnne Drake, associate professor in the Department of Food Science, traveled to Phoenix, Ariz., to present a paper on her current research titled Defining Dairy Flavors — and to receive the American Dairy Science Association’s Foundation Scholar Award for Outstanding Research and Teaching in Dairy Foods.

Drake, whose research specialty is sensory analysis and flavor chemistry, was honored during the ADSA’s annual meeting. She was recognized for her highly ranked teaching and for the impact she has had on the dairy industry through her flavor research, including her development of sensory lexicons or standardized languages to describe flavors of cheeses and dried dairy ingredients and her identification of the chemical sources of the dairy flavors.

“Sensory language is simply a set of words that are defined with chemical references to describe flavors in food,” says Drake. “It’s a quantitative research tool that helps us move forward in understanding the biochemistry and physical properties of dairy foods, which are things we need to do if we’re going to deliver the right products to the right customers.

“Sensory analysis is important because we have to have a way to document how flavor and functional properties are perceived by humans,” Drake says. “This is a competitive market, and we need to understand our products so that we can help deliver specific products that developers want and consumers want in the United States and globally.”

She explains that the wine industry has for years had a “flavor wheel” with words describing variations in wine flavors. Similarly, Drake’s cheese flavor wheel offers specific descriptive words, which can be linked to particular chemical combinations, leading to the creation of flavor profiles for cheeses.

“The sensory languages help us to understand and interpret what role chemical volatiles play, so we can understand the biochemistry of our product,” Drake says.

For example, the words “cowy/barny” refer to a specific flavor in cheese with a chemical flavor reference of a mixture of p-cresol and isovaleric acid. The flavor is reminiscent of farms and animal sweat, Drake says. Thus if in a region in the U.S. or abroad, consumers show a preference — or a distaste — for cheeses with cowy/barny flavor, then producers know what flavor components need to be present or absent to yield the types of cheese consumers prefer.

Most flavors are aromatics, or volatile flavors which are perceived by smell, Drake says. In fact, she explains, 98 percent of what is considered taste is actually smell, or perceived on nasal epithelial cells at the back of the nasal cavity. The distinctive flavors of chocolate chip cookies and a banana milkshake, for example, are volatile components perceived by smell. Only sweet, sour, salty and bitter are perceived by the tongue.

So when Drake is breaking down cheeses to chemical compounds, she is extracting the volatile components to find which ones have aroma or flavor-contributing activity.

It’s the process she recently used to determine what particular chemical compounds cause “nutty” flavor in Cheddar cheese. “That’s a very desirable flavor in Cheddar cheese, but it’s also very elusive. And the theory is if we can figure out what specific volatile compounds cause nutty flavors, then we could trace that back to learn how those flavors are formed,” she explains.

She selected cheeses that have been found, through use of the cheese flavor lexicon, to have high intensities of nutty flavor and also selected similar cheeses that don’t have the nutty flavor. “Then we took these up to the lab and pulled them apart biochemically,” Drake says.

“You have to do both, the flavor chemistry and sensory analysis. When we have completed the volatile analysis, we then take those compounds, put them into cheeses that don’t have that flavor, then give them to a sensory panel to evaluate in a blind study and see if we get any hits on nutty flavor.”

Consumers are variable, and they use their own languages, Drake says. “What Cheddar cheese means to 10 consumers could mean 10 different things. And it’s certainly not the same thing that Cheddar cheese means to an expert.”

By using the defined sensory languages in conjunction with consumer testing, Drake can interpret if what consumers describe in their own terms is nutty or cowy — or “brothy,” “fruity,” “mothball” or “catty.”

“The beauty of these languages is that they’re very versatile,” says Drake. “They can help us with the fundamental science of things, and they can also help us on the marketing end, understanding our consumers. So they help us on both ends of selling the product.”

Drake can also go back and get the demographic information — sex, income, age, how often cheeses are bought, why buyers choose them — received when she polled the consumers and relate demographic information to specific flavor profiles.

That kind of information, of course, is highly valuable to dairy product manufacturers.

“We do an awful lot of work with the dairy industry,” Drake says. “Part of my job for the last three-and-a-half years, since the language came on line, has been to work directly with companies. I visit companies typically four to five times a year and do on-site workshops. Right now we’ve got two California companies that are sending cheeses all the way here to get the flavor profiles on their products.”

Meanwhile a Texas chocolate milk producer has enlisted Drake to provide sensory analysis information to use for marketing from a consumer perspective. In other studies of chocolate milk, Drake’s group developed a sensory language using 28 commercial chocolate milks that participated in the project. With varieties of flavor compounds yielding lexicon terms such as “malty,” “stale,” “cardboard” and “burnt, Drake says, “What you can see is that all chocolate milks are definitely not created equal.”

The paper she delivered at the ADSA meeting was partially derived from a current investigation to understand the variability in flavor and stability of skim milk powders, working with three participating producers, “who probably represent 75 percent of the U.S. milk powder supply,” she says. “They’re all on the West Coast, and three times a year for the next two years they’re shipping 200 pounds of powder from each of their plants to us to study the flavor variability.”

And last year she collaborated with researchers from New Zealand and Ireland studying international and cross-cultural perceptions of cheese flavor.

“There’s always something different going on,” says Drake, who also team-teaches food microbiology in the fall and in spring conducts a sensory analysis course cross-listed for both graduates and undergraduates.

That’s an endeavor that soon will grow, as well. “Sensory analysis has been mandated as a necessary skill for all undergraduates in food science,” Drake says, “so we’re having to change our curriculum to make sure all undergraduates have exposure to sensory analysis.”

Drake regularly conducts on-campus workshops that attract participation from companies in states such as California and Wisconsin. “I think it’s noteworthy that companies from those states come here,” Drake says. “There’s very little dairy industry in this state, but because of this expertise, these companies from the big dairy states come here.”

Soon Drake, who was once a licensed cheese maker, hopes to establish a program to offer short courses on cheese making, and she is working with Golden LEAF to support that effort. “We have a lot of people in the state who are interested in starting that type of business but don’t have a place to go. Cheese making could add needed value to the dairy farmers’ products,” she says.

Still, throughout all this teaching, researching, traveling and consulting, for Drake, one thing remains constant: “Flavor is my big thing.”

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