Like Chips in the Night

By Judith Stone|Tuesday, February 01, 1994
RELATED TAGS: SENSES
People are impressed when William E. Lee III tells them he has a patent in chip technology. "I just leave out the word potato," he says.

Lee is an associate professor of chemical and biomedical engineering at the University of South Florida in Tampa. Besides teaching, he advises public and private agencies on hazardous waste treatment and other environmental problems. (He's the fellow who wrote "Decaying Corpses: An Overlooked Source of Water Pollution?") Lee has investigated the use of metabolic-rate measures for the early diagnosis of serious illness.

But Lee also studies the sensory attributes of salted snack food, chiefly the chip. By avocation, he is the Crown Prince of Crisp, the Captain of Crunch, the Tsar of Tsnap.

Crispness and crunchiness are the sensory qualities that make or break the simple chip. Lee, who worked for seven years as a food sensory researcher at Procter & Gamble in Cincinnati before entering academia, is arguably1 the nation's leading expert on C and C. When prestigious salted- snackmeisters wish to compare their products with competitors'--we're talking companies with names the mere sound of which would summon your spittle--they call on Lee.

His job is not to create crispness but to measure its mechanics and perception by consumers, to quantify what goes on in the hearts, minds, and mouths of America.

"Crispness is sensed in two places," Lee explains. "One is the mouth, by nerve endings including those of the teeth, which create a sharp, sudden, complete break, like the shattering of glass.

"The other place is the ear. Auditory information is important in assessing a food." (Rule number one: If your hamburger moans, send it back.) "You can tell from across the room, just by listening, if a chip product is fresh or stale--a redundant source of information, of course, since you can taste whether it's stale or not." (But it's useful data for party navigation. As food researchers Rodgers and Hammerstein put it, 'Some enchanted evening/ You may hear a Frito/You may hear a Frito/Across a crowded room. . . .')

"Noise is also a source of enjoyment. People will move snack food around the mouth to maximize noise. Kids have what I call noise wars--they crunch in such a way that they're throwing noise at each other. Or look at- -or more to the point, listen to--men sitting around eating potato chips in front of a football game."

Lee has run experiments in which subjects don white-noise headphones that rob them of auditory feedback as they chew. "The eating experience becomes boring more quickly--or remains exciting less long." (Has anyone considered marketing white-noise tapes as an appetite suppressant? I've always wondered about the button on my tape recorder that says NOISE REDUCTION; it must have to do with dieting.)

"Researchers have also done mechanical tests outside the mouth trying to understand crispness," says Lee. These involve an instrument that pushes a needle or pin through a chip at a slow, constant rate, fracturing the snack in a reproducible manner, so its sound and fragility can be studied. "Some people in the field," Lee notes, "have also played around with artificial mouths." (Rest assured that inflatable love dolls do not figure in chip research; that would be the Polythene Pam lab next door.)

Let us distinguish crisp from crunchy, right here, right now. "Crispness disappears very fast in time--four or five bites and it's gone," Lee explains. "A crunchy product, like a tortilla chip, is still going strong after ten bites; there are still hard bits in the mouth."

Sometimes, of course, the characteristics of the chewer are as important as those of the chewed. "You can make some inferences about personalities when you're studying oral residence time--how many chomps it takes for the food to disappear," Lee says. Some people attack their food; others perform a secretive nibble. "With the attackers, oral residence time can be measured in seconds. The quiet nibblers tend to be female; attacking food without savoring it seems to be a macho man thing." (Lee wasn't sanguine about a product I proposed: Testostoritos, a toasted chip made of corn, male hormones, and nails.) "It's not always pretty; sometimes they spray. We find the most crumbs underneath these people's places."

But Lee won't be daunted, let the chips fall where they may. (There. We've gotten it out in the open. Can you imagine the restraint it took to wait this long to engage in the chip thrill of salted-snack paronomasia? I want to corral it all in this paragraph to avoid temptation. Lee, a frequent victim of what some insist upon calling the lowest form of humor, has donated "I don't have a chip on my shoulder" and "My dad says I'm a chip off the old block." Here are a handful of loose japes; mix 'em, match 'em, trade 'em with your friends: Mr. Chips, cash in his chips, Chippendale, Chippendale's, Chip of Fools, chip shot, chipskate, Your Chipship. You might be able to do something really good with artist Edvard Munch, if you finesse the pronunciation. Let me know.)

Whether ingested by a nibbler or an attacker, a crunchy product is louder for longer. But a crisp product creates higher-pitched sounds, Lee discovered. Using an electronic device called a signal analyzer, Lee measured the airborne sound generated by a series of ten consecutive chews of potato and tortilla chips. (For the sake of uniformity, subjects chewed in time to a metronome.)

"Commercially available potato chips and tortilla chips were utilized," Lee wrote in "Analysis of Food Crushing Sounds During Mastication: Frequency-Time Studies." "Potato chips were separated by size and only those with an estimated equivalent diameter of 6 cm and generally free of large air pockets were retained.2 Stale4 samples were made by aging for 48 hours at room temperature and a relative humidity of about 60 percent."

Fresh samples were louder and emitted higher-frequency sounds than stale samples, Lee found. The foods deemed crunchy were perceived as harder to eat--"[more] work input is necessary to effect size reduction in the mouth."

What food sensory researchers call "perceived mouth location" (I've got the impression that mine's under my nose) is important in subjective readings of crunchiness and crispness. "The longer you use your teeth, the crunchier a product is considered," Lee says. "If the food shows up in the middle of the mouth and the person is using her tongue for compression, that means the product is doughy, not the consistency you want. With a salty snack we want to maximize teeth time and minimize tongue time." A superior salty snack, in other words, is the opposite of a French kiss.

Taxonomically speaking, Lee says, the salted snack category can include not only potato, corn, and tortilla chips but also, at some food companies, pretzels and crackers. "If you start to drift into bagels, you're getting into baked goods," he reports. "But sometimes people even include peanuts and, occasionally, other peripherals, like popcorn." (I think Paul Newman has the best peripherals; frankly, his peripherals make Orville Redenbacher's look like withered pods.)

But I drift into bagels. The area in which Lee has broken ground is the study of food sensory perception over time. "Take the sweetness of a beverage," he says. "If you develop it using single sips, research will tell you more is better. I say, drink ten consecutive sips, then let's talk." (Well, what are you waiting for? Go do it.) "Over time, sweetness--a pleasant attribute--becomes disgusting."

In the old days, Lee says, if a company wanted to evaluate chocolate, for example, researchers would ask a subject to eat a piece and then mark a ballot, rating his response from zero, "not sweet," to ten, "disgusting."

"Let's say he assessed it at a seven. That didn't tell the researcher a lot. When did the seven rating kick in? The first four or five chews, there's no sweetness at all. The final chews may have been too sweet. We weren't capturing any of the dynamics of tasting with this standard technique.

"My theory wasn't that more is better, but that how a food attribute is presented over time is what counts: the curve generated after the subject is done. The y axis is intensity (or like-dislike, or sweetness, or crispness), and the x axis is time. Intensity versus time-- it's that simple."

The coming of personal computers revolutionized the tracking of food's temporal behavior in the mouth. "It was hard to do without a computer," Lee recalls. "You could use a piece of paper and have people mark a data point as someone with a stopwatch yelled out 'Now!' every five seconds. The trouble with that was that people could see the previous seven or eight points creating an evolving curve, and that biased them. Research subjects tend to go for what they think the researcher wants."

Today, thanks to Lee and his colleagues, number crunching is easy. "For tracking crispness, sweetness, and other attributes, there's a line on the computer screen. The left-hand side is labeled 'none,' the right-hand side 'extreme.' The subject moves a mouse to show the intensity of an attribute at each moment. I've also asked them to rank 'pleasant' and 'unpleasant,' 'like' and 'don't like.' For studying mouth location, we ask subjects to use the mouse to move an arrow around an on-screen picture of a jaw, showing where they think food is located in their mouth each instant of time."

Lee's patent, by the way, has nothing to do with computers but everything to do with C and C. "Basically I made a corn chip with a potato- chip texture. You might think, 'So what?' But at the time, corn chips had a mealy, gritty texture, and I was able to make them thin and crisp." The resulting product, sensibly dubbed Thin and Crispy, "filled a hole in the snack universe. It was like a Tostito that melts in your mouth." Alas, it wasn't a smash (and I mean nothing by that). "Some people like to use chips for nachos and dipping, so they want more structural stability."

This is the point at which we might share a metaphorical wink- and-nudge combo and snicker (no snack intended) about what a wacky thing it is to engineer the structural stability of appetizers, or write articles like "A Time-Intensity Study of Prolonged Sweet Stimuli." But I'm not making fun here; I'm having fun, and that's different.

I find it deeply satisfying to learn that scientists are studying ordinary stuff I do every day, like chewing and swallowing (or "oral events," as Lee calls them, and if you have any comments on that nomenclature, keep them to yourself). I'm tickled when highfalutin terms are applied to a lowfalutin or midfalutin activity like face-stuffing. I think it's cool to learn that ripple chips were invented to provide more structural stability for dipping. I like knowing that food research shows consumers enjoy the low to moderate levels of pain created by spicy foods. (Scholars believe that's what Handel was trying to capture when he wrote the "Jalapeño Chorus.") I think of these fun facts not as a waste of scientific endeavor but as rest stops along the information superhighway. The work also yields data both scientifically precise and useful.

Here's what I mean by useful: In a paper he wrote called "Time- Intensity: The Temporal Aspects of Sensory Perception," Lee looked at the way eaters perceived foods of varying viscosity over time. (You may prefer "thickness" or "gooeyness" to "viscosity.") In any case, in his paper Lee cites work showing that "higher-viscosity chocolate puddings will display less flavor than lower-viscosity puddings, even though the level of chocolate is the same in both products." Vindication! If only I, as a young girl, could have explained to my mother that it was sound scientific principle and not impertinence or whim that caused me to stir my pudding and ice cream until I'd whirled it into a chocolate soup!

Don't think I'm complacent about food research; we all understand that it can be a force for evil as well as good. Here's something that really troubled me: two years ago a food industry giant that
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