Comparison of odors directly and through profiling

Odor qualities of 10 odorants were compared by 50 panelists of 4 cooperating laboratories of the ASTM E-18 Sensory Evaluation Committee. The odorants were: acetophenone, anethole, 1-butanol, carvone, p-cresylmethylether, cyclohexanol, 1-heptanol, 1-hexanol, phenylethanol, and pyridine. In one method, dissimilarity was scored directly on a 7-point scale; results from different laboratories correlated at p < 0.001, and identical odors yielded scores well-discriminable from those for non-identical odors. In another method, odors were compared indirectly, by comparing their edited multidimensional profiles obtained using Harper's scale expanded to 136 descriptors; mean profiles from different laboratories correlated at p < 0.05 in 97 percent of cases. To eliminate semantic effects, a Chi-Squared statistic was applied to the individualized descriptor usage counts, providing a dissimilarity measure, DCHI = In [(coefficient of association)]; its value from different laboratories correlated at p < 0.001. However, a distinct discrimination of identical odors was possible only after adding some descriptors specific to alcoholic odors. DCHI and dissimilarity scores related curvilinearly, but a linearity (r = 0.88) resulted for DCHI vs (score8-score)⁠. Thus, DCHI derivable from sufficiently articulate multidimensional profiles adequately substitutes for the direct dissimilarity scores; in addition, profiles indicate the nature of the dissimilarity. Fortran programs for the profile analyses are given.