Comparative Free Choice Profiling

Amongst the most recently developed sensory descriptive methods. Comparative Free Choice Profiling, also called Flash Profile, was particularly suitable for us, because it... 

The aim of is to provide quick access to the relative positioning of a set of products. Its principle is very simple. It consists of the combination of a free choice of attributes, as in free choice profiling (FCP), and of a comparative evaluation of the samples for each chosen attribute (attribute-by-attribute protocol) and quantification by the means of ranks. This usually goes with a simultaneous assessment of the whole product set and direct focus on inter-product differeuces. 

Flash profile is a technique developed by Sieffermann (2000) that combines free-choice profiling with a comparative evaluation of the product set. This method is divided into two consecutive steps. It first consists in asking the assessors to individually generate their own attributes to describe the product set. In the second step, assessors are asked to rank the samples according to each of those attributes. As assessors have the whole sample set in front of them, it forces them to focus on the differences they perceive and to generate discriminant attributes. 

To be able to compare consumers and technical vocabulary, participants must not influence each other, whether they be consumers or test drivers. In fact, very experienced experts have a strong influence on each other. Therefore, a free choice profiling method that does not require discussion with the rest of the panel is preferable. Besides, test drivers are available for less than 10 h a month, so a fast methodology is needed. Due to the complexity of the products and the constraints of the evaluations, we choose to use Flash Profile (FP) (Dairou and Sieffermann, 2002 Delarue and Sieffermann, 2004 Tarea et al 2003). 

Construction of the free energy profile (Figure 6.7) for the whole reaction required a choice of thermodynamic standard state, since bimolecular and unimolecular rate constants were being compared. This was taken as 40 pM, the physiological concentration of the triose phosphates. 

Aside from the recruitment of experienced subjects and the free choice of attributes, the need for training is further reduced by the comparative evaluation mode. The fact that assessors have simultaneous access to the whole sample set indeed allows direct comparative evaluation and forces the assessors to focus on the differences they perceive. This leads them to generate discriminant attributes only. This also means that, in comparison to many conventional profiling methods, more autonomy is left to the assessors. 

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