Perception of components in binary odour mixtures

Abstract

Changes in perceived intensity and odour quality of mixtures of trans -2-hexenal and trans -2-decenal, common products of fat oxidation, were measured using category scales and a profiling technique, respectively. Twenty three quality terms appropriate to these odours were derived from a list of 152 descriptors and used to obtain profiles of the mixtures. Qualities perceived in mixtures appeared to depend on the relative intensities of the odorants; however, only a small intensity difference between odorants was necessary for the qualities of the higher intensity component to predominate, or for only that odorant to be perceived. When odorants were of approximately equal intensity, most of the qualities of both odorants were perceived. Scores for intensities of mixtures agreed well with those predicted by the vector model of intensity summation and a value of 109° for α was obtained for the two odorants. Although there was some evidence of intensity enhancement and suppression, the general effect resulting from mixing the two odorants confirmed the earlier finding of Jones and Woskow (1964), that the total intensity of a mixture is always less than the sum of the intensities of the two components.