Sensory Testing and Functional Foods

September 2001

Sensory Testing and Functional Foods

By Jeff Kroll and Dan KrollContributing Editors

The subject of sensory testing vis-a-vis functional foods is not particularly complex, but as everyone views the category from his or her own perspective, it would help to review the definition of a functional food.

Functional is the operative wordThere may not be a definition of functional food to which an exception can’t be found. Suggesting, say, a functional food is one that has an effect on the body in addition to normal physical effects, or that it has been artificially produced to have verifiable health benefits, is to ignore such products as, for example, cranberry juice or coffee.

Cranberry juice has long been used for its effects on the urinary tract, and coffee for the stimulating effect of its caffeine. Since neither is a manufactured food, or result in any effect that wouldn’t be considered ordinary, neither fit the definition. Both, however, can be classified as a functional food.

Nutraceuticals typically are dietary supplements, often containing nutrients such as vitamins or bioflavonoids, which are not taken for flavor or ordinary nutritional benefits, but for specific health or physiological reasons. While not generally considered foods, they often are added to foods, or delivered in food-like forms such as shakes, fruit-flavored drinks or snack bars. Again, there are nutraceuticals that don’t fit comfortably — or at all — into this broad definition.

Eventually we begin to identify functional foods and nutraceuticals as we might identify art or pornography — we recognize them when we see them.

But it gets a bit easier to define functional foods if we focus on the obvious: the word function. A functional food might be thought of as one that serves a function beyond ordinary nutrition, where a modification, added ingredient or an intrinsic ingredient may impart the functionality. From a marketing standpoint, which is certainly a key issue in functional foods, we probably could expand that definition by looking at a functional food as one for which the functionality is promoted as a primary reason for ingesting the product.

In other words, a primary difference between functional foods and all other food products may be how they are marketed. For example, rather than emphasizing some ordinary attribute as flavor, aroma or texture, marketing for a functional food may highlight some immediate physiological reaction or long-term health benefit.

Sports drinks claim to help consumers rebound quickly from the exhaustion of heavy physical activity. Calcium-added orange juices claim to delay or prevent the onset of osteoporosis some 20 years hence.

Everyday food products are sold on the basis of the pleasure they give, or how they meet normal nutritional needs. Functional foods target some known health need or specific benefit. Perhaps broccoli, yogurt and cranberry juice are somewhere in the middle, being promoted for taste as well for general good health.

Marketers of functional foods and nutraceuticals have an extra burden to bear. The flavor may not be something they want to talk about for a particular product, but unless the taste is acceptable and the consumer market is willing to use the product, none of the benefits will be achieved and the product will be without purpose. Sensory testing, therefore, is at least as important to functional foods as it is to fast food or chocolate chip cookies.

Motivating purchase and useA recent segment on ABC TV’s “Good Morning America” posed the question: Is it possible to quench your thirst while enhancing your mind? The news segment dealt with the current popularity of herbal drinks, and representatives for some of the largest soft drink corporations defended the functional beverages. However, organizations such as Center for Science in the Public Interest and government regulators, including the FDA, are concerned that some drinks don’t live up to their claims, and could even be harmful for some consumers. That’s where clinical trials and scientific study come in — to prove safety and efficacy. Sensory plays only a limited role here.

There is one area in which sensory testing can be used to evaluate the efficacy of some functional products. Behavioral protocols can be established to measure mood or a respondent’s state of relaxation. Developing such standardized measurements means a variety of products can be measured for such things as their calming effects, their ability to induce sleep, their impact on a patient’s degree of mental alertness and so forth. This has not been the usual purview of sensory testing, but is well within its realm.

Ultimately, it’s the taste that determines whether the consumer will buy a product. If for “the taste” we read “an acceptable taste,” that’s where sensory testing comes in.

Determining the acceptability of a functional food is much the same as determining the acceptability of a pizza or candy bar. That is, whatever the product, the goal is to ascertain consumer acceptance or preference and, eventually, the consumer’s intent to purchase. So it should be no surprise that sensory testing methodologies are the same for both. Traditional taste tests conducted in central locations and home-use tests, as well as scales — such as the nine-point hedonic scale and the five-point just-about-right scale — are used for all food product categories.

The difference in the sensory testing of a functional food is in test protocols. Typically, food products can be tested in ordinary laboratory conditions. A salad dressing, for example, tastes the same whether sampled at an isolation booth counter or at your home dinner table. The correct preparation of foods is more important to getting accurate, reproducible information than eating the foods in familiar or somehow appropriate surroundings, and the respondent’s reaction to most food doesn’t change because it is eaten in a focus room.

On the other hand, a functional food promoted for use during strenuous physical workouts does demand that the sampling be done in an environment appropriate to the intended use and relative to the suggested timing. In other words, it needs to be tested at the “point of sweat.”

An example is sensory testing on a functional food nutritional bar that claimed to have positive effects on the cardiovascular system. It was recommended that the bar be consumed before bedtime.

While this timing was for functional reasons, the protocols called for a bedtime sampling. The acceptability of the flavor, texture and aftertastes of the bar would not necessarily have been the same if they were sampled in the afternoon.

Narrower target marketsIt always is important that products be tested with the intended target market, but this is more critical with functional foods. Furthermore, the target market often is difficult to recruit and screen because it generally is narrower than that for the usual food product found on grocery store shelves. In extreme cases, functional foods may need to be tested in very limited circumstances with very specific market groups.

Our sampling of a food supplement intended for terminally ill patients had to be conducted in hospice. Acceptability equated with compliance, and as this was the primary source of nutrition for the patients, it was necessary to have a product they were willing to consume in a single sitting.

The results were counter-intuitive, and would have been misleading if conducted with any other group. The acceptable product was very bland as the patients could not tolerate high sweetness levels or strong flavors. The consistency of the product was a key attribute — too thick and it was difficult to drink, too thin and it was perceived as not being able to supply total daily nutrition.

Concepts require contextsEven concept testing and packaging tests for functional foods can depend on appropriate settings. This goes beyond the obvious need to test a geriatric food supplement, for instance, with the target market to determine whether they have the handgrip strength to open the container. Consider the delivery system of a beverage intended to help people recover after strenuous workouts or intense sports play. In a sensory testing lab, a large, smooth mouth on a bottle may seem unnecessary. But in a gym or on the field, a wide bottle mouth becomes an important part of the mystique, allowing consumers to gulp the drink.

Furthermore, attitudes and atmosphere during exercise call for a bottle that is conducive to being grabbed aggressively with the whole hand. In a congruous setting, softer plastic bottles are judged more pleasant to the touch, not for any aesthetic reasons, but because squeezing the bottle to force the flow of the drink is considered more satisfying to the consumer. These last two design elements might be unappreciated, or even overlooked, in a laboratory.

Similarly, a sports-nutrition bar aimed at helping athletes recover from long workouts was tested after the practice workouts of professional sports teams. The exhausted professional athletes considered the bars, which were judged very sweet when sampled in more traditional testing environments, as an acceptable snack or nutrition substitute.While sensory testing generally is unable to establish the true utility of a functional food, it often can determine a consumer’s perception of product efficacy. Such a placebo effect actually can be considered a use benefit. Again, frame of reference is likely to be a major factor in how the respondent judges the product.

The perceived refreshment and/or recovery value of a sports drink changes when the comparison with water or a competitive brand is done in the gym or after playing a game. Also, an attribute’s intensity that may be acceptable, or even desirable, when the drink is sampled in a lab or at a mall may be completely unacceptable after a physical workout. The opposite also may be true — the consumer may view a chemical or medicinal taste as undesirable in a lab test, but accept it as a clue to product efficacy in the appropriate circumstances.

The consumer’s willingness to trade off some degree of attribute preference, in exchange for functionality, sometimes can be determined during the initial concept testing. To test such tradeoffs, the product’s functionality concept is not revealed until the respondent has reacted to various attributes, projected pricing or packaging. The perceived desirability of the function then can have a marked effect on the concept’s acceptability, as well as the consumer’s intent to purchase or interest in trying the product.

In other words, products that have been modified for a functional purpose tend to be held to a different standard. While they may be equally as acceptable as the unmodified version, they are not interchangeable. Understandably, the most difficult kind of testing for a functional food is blind tasting. The consumer is willing to evaluate in the context of the concept, but generally no allowance is given for the modification as a one-for-one substitute.

Expectations lead the way in the sensory testing of a functional food, and characteristics can be seen to signal benefits. While the actual methodologies and scales are no different from any other product or group of products, framing a test to be appropriate relative to the intended use of the functional food is key to obtaining reliable marketing data.

Jeff Kroll and Dan Kroll are executive vice presidents with Peryam & Kroll Research Corporation, a Chicago-based firm that has been a leader in consumer product testing for nearly 50 years. Peryam & Kroll estimates that functional foods are currently about 10% of their marketing and sensory research assignments.

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