The perception of fragrance mixtures: A comparison of odor intensity models

A comparison of two psychophysical odor intensity models and their effect on the prediction of the odor character for perfume mixtures is presented. The odor value (OV) and Power‐Law models were applied together with previously developed perfumery ternary diagram (PTD®) and perfumery quaternary diagram (PQD) methodologies to map the perceived smell of quaternary and quinary fragrance mixtures. A diffusion model was used to simulate the evolution of liquid and headspace concentrations. The evaporation of perfumes starts with a fast ethanol release, then the diffusion of the fragrant components. The composition paths were predicted through the evaporation lines plotted in the PQD. The two odor intensity models present differences in the initial perfume impact, but after some time tend to similar profiles. The Power‐Law predicted higher ethanol intensities than the OV model, due to its exponent. Introducing water in perfume formulation fixes ethanol in the solution, thus reducing alcohol perception. © 2009 American Institute of Chemical Engineers AIChE J, 2010