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 [Other ripe fruit(s), Other positive attribute(s) and Other negative attribute(s)] could be of great additional interest in the characterisation of different samples. However, as they are not specifically defined it is difficult to reach a descriptor consensus among assessors evaluating the samples. This situation is similar to that produced when using a Free Choice Profile and so the Generalised Procrustes Analysis (GPA) could be extremely useful in obtaining all the information contained in these three generic descriptors. In this study GPA was applied to the descriptors generated by a 25 member expert panel under the headings Other ripe fruits and Other positive attributes when evaluating 11 samples of virgin olive oil from the variety 'Arbequina' grown in three different regions. The Generalised Procrustes Analysis was efficient in the sensory characterisation of the 11 samples studied using the information provided by the two positive generic descriptors included in the official sensory profile. The overall result was equivalent to that obtained using Correspondence Analysis, although the GPA gave more information since it also included the intensity of each of the descriptors and was less affected by odd descriptors. This technique was as useful in the characterisation of the samples as the other six positive descriptors defined in the official sensory profile (Olive fruity, Apple, Green, Sweet, Bitter, and Pungent), providing additional information of great scientific and commercial interest. (C) 2001 Elsevier Science Ltd. All rights reserved.