Different Types of Descriptive Sensory Evaluations

We all have our favorite foods. And we all have different reasons for liking them. For some, it’s the velvety texture that oozes out of each bite, or the tingling sensation that dances across their tongue. For others, it’s the spicy kick that sends their taste buds into overdrive or the floral aroma that transports them back to childhood on a wave of nostalgia.

Every human sense contributes to our experience when consuming food. Sight, smell, taste, and touch play more obvious roles, but even the sound of a crisp cracker breaking apart or fizzing bubbles climbing up the walls of a glass trigger a response somewhere in our minds.

These sensations form and strengthen our cravings for certain types of food, which is why food manufacturers and food marketers are so keen to understand even the most nuanced characteristics of their products. The more they know about their product, the easier it will be to find a market for it. To do that, they’ll perform a descriptive sensory evaluation.

What is a descriptive sensory evaluation?

A descriptive sensory evaluation provides a detailed profile of a food product’s sensory attributes, as well as a qualitative measurement of each attribute’s intensity.

Every sensory assesment is conducted by human subjects who have been specifically trained to obtain a comprehensive analysis of four key qualitative sensory descriptors:

The formative evaluation also provides a quantitative analysis of the intensity (or degree to which a characteristic is present) of each sensory descriptor.

When to conduct a descriptive sensory evaluation

Sensory testing can assist food manufacturers at nearly every stage of the production process including:

• Research and development
• Quality control
• Define product attributes
• Product comparison
• Shelf-life studies

Whether your goal is to identify your product’s natural attributes, create a specific profile, or understand the perceptions and preferences of potential customers, conducting a sensory evaluation is crucial to success.

Sensory evaluation methods

Depending on your needs and stage of production, there are multiple sensory evaluation methods available – ranging from quick and inexpensive to highly-specialized and comprehensive – that you will find useful.

Flavor Profile Method

Developed by scientists at Arthur D. Little in the 1940s, the Flavor Profile method is often referred to as the “mother” of many descriptive evaluation methods and has been used extensively in the food production industry.

The Flavor Profile method describes flavor in terms of five major components: character attributes, attribute intensity, order of attribute appearance, aftertaste, and amplitude (the overall impression of the analyzable and non-analyzable flavor components). The original scale for the flavor profile was five points: not present, threshold, slight, moderate, and strong. Over time the scale has been adapted to more points (first seven, now 14) to accommodate more differentiation in the intensity.

A highly-trained panel of typically four to six members evaluate the product separately and then discuss their findings as a group to determine a consensus profile. This consensus provides a mean value – not an average of the panelists’ scores, but a single score agreed upon by all panel members.

Recommended for: Research and development, product comparisons, defining product attributes, quality control, shelf-life studies

Advantages: Small, trained panel focused specifically on flavor

Disadvantages: Potential for bias or influence by dominant panel members

Texture Profile Method

Dr. Alina Surmacka Szczesniak and her team at General Foods' Technical Center developed the Texture Profile method in the 1960s. Their goal was to develop a lexicon and set of procedures that enabled objective, repeatable evaluations of texture on nearly any food type. To do so, the team also created the General Foods Texturometer, an instrument which could amplify their sensory work and objectively quantify texture. The Texturometer ensured unbiased consistency while saving both time and money compared to human evaluations.

In 1963, Dr. Szczesniak's article, The Texturometer - A New Instrument for Objective Texture Measurement, introduced five core parameters (hardness, cohesiveness, adhesiveness, viscosity, and elasticity) and three secondary parameters (brittleness, chewiness, and gumminess) for evaluating food texture.

Recommended for: Research and development, product comparisons, defining product attributes, quality control

Advantages: Easy to conduct, unbiased results

Disadvantages: Likelihood for operators to accept results without test refinement

Spectrum Descriptive Analysis

Gail Vance Civille developed the Spectrum Descriptive Analysis method during the 1970s and presented the method at the 3 IFT Sensory Evaluation Courses in 1979. The Spectrum Descriptive Analysis combines the rigorous training and structure of the Flavor and Texture Profile Methods, augmented with a larger panel group (up to 15 people), a more refined scale (typically 150 points, depending on the product), and the application of statistical methods to the descriptive data.

The Spectrum Descriptive Analysis provides product developers with clear documentation of product attributes and intensities, allowing product profile comparisons to be conducted with consistency. Reliable data gives the product developer insight regarding the impact that process, ingredients, and time have on the product’s sensory characteristics.

Recommended for: Research and development, product comparisons, defining product attributes, quality control, shelf-life studies

Advantages: Trained panel, comprehensive product analysis

Disadvantages: More time consuming and costly than other methods

Quantitative Descriptive Analysis

Developed by Tragon Corporation—in partial collaboration with the Department of Food Science at the University of California, Davis—to find an alternative to the poor statistical data obtained by the Flavor Profile and related descriptive methods.

Accepting that humans are good at judging relative sensory differences but poor at evaluating absolute differences, the Quantitative Descriptive Analysis (QDA) method suggests multiple product evaluations to capitalize on panelists’ skill in making relative judgments with a high degree of precision. This philosophy has made QDA methodology distinctly different from methods which try to identify absolute differences between products (e.g. Spectrum Descriptive Analysis).

A panel of ten to twelve people participate in individual evaluations and asked to aid data collection by quantifying product attributes using a line scale that is six inches in length with intensity markers located every half inch.

Recommended for: Research and development, product comparisons, defining product attributes

Advantages: Aggregated analysis and intuitive data outputs

Disadvantages: Data variances based on panel participants

Free-Choice Profiling

Free Choice Profiling differs from the previously described methods in two key areas. First, the participants in each panel are “untrained” consumers. While they receive instruction on how to conduct the evaluation, they are not selected based on their skill or experience in identifying subtle differences in product attributes. Second, the participants primarily focus on providing “liking” or “acceptance” responses (among other qualifiers) as a method of measurement for each specific attribute, rather than an empirical rating.

Similar to the Quantitative Descriptive Analysis, the participants’ responses are then aggregated to form a consensus value for each attribute.

Recommended for: Research and development, product comparisons

Advantages: Quick, inexpensive, provides insight into consumer perceptions

Disadvantages: Inconsistent lexicon and varying interpretations of attributes

Medallion Labs Sensory Evaluations

Choosing the right sensory evaluation for your needs is crucial to understanding your product and potential customers’ perceptions. The method of choice for Medallion Labs is the Spectrum Descriptive Analysis and our area of expertise lies in documenting the flavor and texture characteristics of consumer food products.