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Previous investigations of the sensory characteristics of sweeteners using a multidimensional scaling (MDS) approach, have involved sweeteners which were not matched for sweetness. Under such circumstances, part of the estimated distance between sweeteners is attributable to sweetness differences. This detracts from the value of the consequent MDS space, when the main objective is usually to investigate sensory characteristics other than sweetness. In this study, the MDS approach was applied to sweetener solutions which were matched for sweetness with 5% sucrose. The direction of any residual sweetness differences was identified by including 1,3,5 and 7% sucrose solutions, all matched to equal viscosity, in the study. From the resulting three dimensional MDS sweetener space, it was evident that Dimension 1 was almost exclusively due to sweetness differences whereas Dimensions 2 and 3 were devoid of influence from sweetness and hence represent the sweeteners with respect to their other sensory characteristics.

In many attitudinal investigations, particularly those involving free-choice profiling, a very large list of variables or features can emerge. Ordination using generalized Procrustes analysis provides a common base for comparing assessors, but the derived configurations are often high-dimensional and difficult to summarize. This problem can be rectified by selecting a small subset of the original set of variables. Methods of variable selection in principal component analysis can be adapted easily for such purposes, but there is no guarantee with these methods that overall data structure is preserved. A recently introduced variable selection procedure that does aim to preserve the data structure as much as possible would seem to be more appropriate. All methods are described and applied to a set of data arising from an attitudinal investigation of meat products. The results indicate that variable selection should be more widely encouraged.

The concept of free-choice profiling allows untrained assessors to participate in sensory profiling. However, it is sometimes the case that such individuals are unable to describe what they perceive when the samples are presented in the isolation of the sensory testing booths. This paper reports an experiment to compare the usual free-choice profile procedure, with a more structured approach based on Kelly's repertory grid method. Generalized Procrustes analysis was used to analyse the data. The sample configurations obtained from both approaches were very similar, as were the interpretations of the main perceptual dimensions.