Importance of Generalised Procrustes Analysis in sensory characterisation of virgin olive oil

Sensory characterisation of virgin olive oil is completely standardised in the European Union. The sensory profile used to evaluate samples is made up of 16 descriptors, three of them being generic. These three attributes [Ot her ripe fruit(s), Other positive attribute(s) and Other negative attribute (s)] could be of great additional interest in the characterisation of diffe rent samples. However, as they are not specifically defined it is difficult to reach a descriptor consensus among assessors evaluating the samples. Th is situation is similar to that produced when using a Free Choice Profile a nd so the Generalised Procrustes Analysis (GPA) could be extremely useful i n obtaining all the information contained in these three generic descriptor s. In this study GPA was applied to the descriptors generated by a 25 membe r expert panel under the headings Other ripe fruits and Other positive attr ibutes when evaluating 11 samples of virgin olive oil from the variety 'Arb equina' grown in three different regions. The Generalised Procrustes Analys is was efficient in the sensory characterisation of the 11 samples studied using the information provided by the two positive generic descriptors incl uded in the official sensory profile. The overall result was equivalent to that obtained using Correspondence Analysis, although the GPA gave more inf ormation since it also included the intensity of each of the descriptors an d was less affected by odd descriptors. This technique was as useful in the characterisation of the samples as the other six positive descriptors defi ned in the official sensory profile (Olive fruity, Apple, Green, Sweet, Bit ter, and Pungent), providing additional information of great scientific and commercial interest. (C) 2001 Elsevier Science Ltd. All rights reserved.