What is a Fresh Scent in Perfumery? Perceptual Freshness is Correlated with Substantivity

Abstract

Perfumes are manufactured by mixing odorous materials with different volatilities. The parameter that measures the lasting property of a material when applied on the skin is called substantivity or tenacity. It is well known by perfumers that citrus and green notes are perceived as fresh and they tend to evaporate quickly, while odors most dissimilar to ‘fresh’ (e.g., oriental, powdery, erogenic and animalic scents) are tenacious. However, studies aimed at quantifying the relationship between fresh odor quality and substantivity have not received much attention. In this work, perceptual olfactory ratings on a fresh scale, estimated in a previous study, were compared with substantivity parameters and antierogenic ratings from the literature. It was found that the correlation between fresh odor character and odorant substantivity is quite strong (r = −0.85). ‘Fresh’ is sometimes interpreted in perfumery as ‘cool’ and the opposite of ‘warm’. This association suggests that odor freshness might be somehow related to temperature. Assuming that odor perception space was shaped throughout evolution in temperate climates, results reported here are consistent with the hypothesis that ‘fresh’ evokes scents typically encountered in the cool season, while ‘warm’ would be evoked by odors found in nature during summer. This hypothesis is rather simplistic but it may provide a new insight to better understand the perceptual space of scents.

Underlying dimensions in the descriptive space of perfumery odors: Part II

“…A recent study (Teixeira et al, 2014) uses a fragrance wheel that does not agree perfumes but rarely in base notes, while the opposite applies to woody odors (see Table 1 of Zarzo, 2013). Thus, further research about how to reach standard fragrance maps is still required.…”

“…Nonetheless, odor maps obtained from untrained subjects in market research also reflect the same two underlying descriptive dimensions (Jellinek, 1992;Richardson, 1999 p. 156), even when using consumers from different countries (see Fig. 1 of Zarzo, 2013). In order to investigate to what extent the sensory odor maps tell us anything in terms of perceptual similarity rather than functional similarity of the materials, one approach would be to obtain matrices of rated similarity by direct comparison between scented products and discuss the resulting MDS projection.…”

“…By counting the total number of times that a given attribute was applied to describe top, middle and base notes of perfumes in this guide, a substantivity index (SI) was calculated (see Eq. 1 of Zarzo, 2013). It takes the value zero for odors only encountered in top notes (i.e., the ones that evaporate quicker), which indicates a low substantivity.…”

“…2 discriminates light vs. heavy odors and it is correlated with substantivity, which is a physical property of odorants. Because the light/heavy odor character is somewhat encoded by molecular structure, it might be primarily innate and evolutionarily hardwired (Zarzo, 2013).…”

Structure–odour relationships reviewed in the postgenomic era

“…An efficient model will necessarily rely on an unambiguous description of the perceptual space, suggesting that linguistics will certainly play a major role. For example, can the descriptors ‘fresh’ and ‘cool’ be considered synonyms? Another way to limit inter‐individual differences would involve the use of a panel of individuals who describe chemicals with appropriate protocols towards a consensus, associating a prototypical odour with a single odourant . Within this postgenomic era, the amount of information gained from the response of ORs, odour descriptors and human behaviours about odourant stimulation remain to be accurately connected.…”