The Napping© / Mapping Profile

Sensory tests

Napping Profile©

Principle

Why a Napping profile©?

This descriptive test is to be used when one wishes to obtain a rapid positioning or representation of numerous products vis-à-vis each other on the basis of general similarities and distances.

These distances between products can be associated with a previously defined grid, such as cooking levels or maturity rates, but more generally, these positionings are carried out on a neutral or flat grid, which is therefore specific to each subject.

The questions associated with this type of test are for example:

“How many product groups are present among these products? »,

“What are the extreme products present among these samples? »,

“How are these samples distributed vis-à-vis each other? » …

It remains necessary to have to compare or position many samples at the same time, often more than 20 products; this requires that all these products can be evaluated in comparison. By this large number, this examination can be only visual and/or olfactory for reasons of sensory saturation, also, these products must not evolve during the duration of this examination.

The subjects are experts in their field, for example oenologists, formulators, engineers (automotive sector, etc.) in order to bring together or distinguish products on characteristics that may be physical or sensory, well identified and known to these experts.

A panel of 2 to 5 subjects may be sufficient to create these representations.

Principle of a Napping profile© ?

Each panelist will have at his disposal all the products presented in the same packaging or in the same form, and associated with 3-digit codes.

Each panelist will then have to, after examining each one, position these products according to their distance or their proximity on a grid, starting with any one, and adding each one opposite the first positioned ones.

The positions of each product may evolve as the positioning of the following products progresses, the panelist will be required to justify, by a free comment, the salient characteristics of this product, explaining this positioning.

We could take, as an example, what a cellar master in Champagne would do to make his blends by positioning the glasses of his cuvées on a paper tablecloth, noting each of their characteristics.

Each panelist positioning each sample on a neutral or oriented grid, it will then be possible to take the x and y coordinates of all of this data in order to calculate all the existing distances between each of the products, by panelist, then for the whole panel. This calculation will then make it possible, by tests of hypotheses, such as for example Student's tests, to identify what these distances are, and whether they are significantly different, between each sample.

Graphical representations will also be possible, either calculated by the means of the coordinates (barycentres) for the previously defined grids or by a multi-dimensional representation (Principal Component Analysis) of these distances for the neutral grids.

Collecting and compiling the comments given by each subject, for each product, will also make it possible to complete this information in an open manner.

Advantages and Limitations of a Napping Profile© ?

These tests can be carried out with a few subjects, each of whom can carry out this examination independently in order to very quickly obtain an overview of the products present on a market or available for carrying out a formulation; this method can also be used on manufacturing batches, to represent a manufacturing day, and highlight non-compliant batches.

However, the representation obtained will not be as precise a description as that of a QDA profile or a Pivot profile.©. It is also necessary that all these products can be available, and be evaluated at the same time.

This analysis can make it possible to identify products representative of each group, and these products can then be studied in more detail, either in an exploratory approach, having also identified the most central or average group by carrying out a Pivot profile© or in a more classic approach by performing QDA-type profiles.

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