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A Crash Course In Crunchiness

Analyze this: Scientists get the goods on food textures

SUNDAY, May 20, 2001 (HealthDayNews) -- To the average junk-food junkie, the crispness of a tortilla chip may not merit a passing thought, but couch potato connoisseurs might appreciate the intricate science behind producing that perfect crunch.

Such challenges are the subject of scrutiny at the Rheology and Sensory Program, part of the University of Arkansas' Department of Food Science. The program is one of the key places that food companies look to for information on the quality of different aspects of their products.

Products tested in the sensory laboratory include everything from cheese, yogurt, hot dogs and meats to baked beans, poultry, tortilla chips and rice.

But if images of undergrads recruited to munch away to their hearts' content for extra credit come to mind, you'd be mistaken.

In fact, one of the main reasons companies are attracted to the lab is the professional sensory panel, which is trained to quantify food attributes, including appearance, aroma, flavor and texture.

Panel members have more than 1,000 hours of experience in analyzing what they eat and drink.

The panelists work individually -- in partitioned booths where food is sometimes even masked by red light -- and then together to develop 200-word descriptions and evaluations of everything from the bouquet of a red wine and the taste of rice to the appearance of fried chicken and, yes, even the crispness of a tortilla chip.

The issue of food texture, however, is the primary focus of the lab's research.

"Flavor is usually the most important characteristic of food," says Jean-Francois Meullenet, director of the lab. "But in many cases, texture can be equally as important."

"For foods that have a particularly bland flavor, the texture can, in fact, be the most important attribute. That can include foods such as potatoes or potato chips, rice or pasta."

If, for instance, the texture of a hot dog made from chicken doesn't match what a consumer expects from the ordinary hot dog, it can diminish the enjoyment, Meullenet says.

"It constitutes what we call a 'violation of the expectation,' and they may not accept the product," he adds.

The process of quantifying a food's texture gets far more complicated than the panel's detailed descriptions. The lab actually uses special equipment to measure the "velocity" at which people eat and then tests foods to make sure they will fall within that average rate of chewing.

"There are differences between individuals in the mechanics of chewing and even the eating rituals in general. So, we do a lot of measurements to see how that influences the way food products break down," Meullenet explains.

The lab also uses special equipment that basically serves as food crushers, measuring precisely how much force it may take, for example, to bite into a tortilla chip.

"You may do a measurement indicating that it takes about five millimeters per second to break a chip, but we know from our other data on the mechanics of chewing that consumers average about 35 millimeters per second, so we know work has to be done to make the chip more suitable."

"The point is to look at what humans actually do when they eat and then try to get the food to conform within that range," Meullent adds.

What To Do

Read more about food science in these HealthScout stories.

Visit the Institute of Food Technologists for more information on food science issues.

SOURCES: Interview with Jean-Francois Meullenet, Ph.D., assistant professor in food science at the University of Arkansas, Fayetteville; University of Arkansas press release
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