Exploring the network of odours shared by an aroma blending mixture

International audienceThe first step of odour perception is an interaction between odorants and olfactory receptors [1]. Moreover, odours perceived in our environment are mainly the result of mixtures of odorants; however, the specific mechanisms involved in their processing remain poorly understood [2]. In previous studies performed at INRA-CSGA [3], the perception of a mixture of ethyl isobutyrate (Et-iB, strawberry-like odour, STR) and ethyl maltol (Et-M, caramel-like odour, CAR) was investigated in comparison with a reference (allyl hexanoate, Al-H, pineapple-like odour, PNA) chosen to evoke an odour close to the one expected in the mixture. The binary specific mixture of Et-iB and Et-M was judged as more typical of a pineapple odour than the individual components. Some studies highlight the significance of the biological function of odorant, that is to say their odour, to understand odorant discrimination [4, 5]. From this perspective, we focused on all the odours shared by the molecules having at least one of the odours STR, CAR or PNA in their odorant description (respectively 22, 154 and 129 molecules). We based this approach on our recent work related to the analysis of a large odorants database [6]. We applied the notion of "social network", used in the social sciences to study relationships between individuals. We followed here a similar approach to describe the network of odours linked to STR, CAR and/or PNA. Thus, if two odours co‐exist in the odorant description of one or several odorants, they are “linked at level L1”. The number of links between two odours is the number of molecules described with these two odours. We identified 348 pairs of odours involving a total of 113 odours. The analysis of the links between the odours revealed strong L1 association between STR and CAR, as well as smaller L1 association between STR and PNA (respectively 40% and 14% of the molecules described with STR odour). Conversely, only one molecule is described with CAR and PNA odours (Furfuryl pentanoate “Fruity-pineapple-apple, caramellic odour”) [7]. Interestingly, the network of the odours highlights numerous links at level L2 between CAR and PNA: 15 odours connect the three odours STR, CAR and PNA, and 24 odours connect CAR and PNA; only 4 and 2 odours connect STR respectively to CAR and PNA. Our hypothesis is that the analysis of L1 and L2 links between odours from large database of odorants would constitute an essential key to identify potential odours/odorants triplets able to form a blending mixture. 1. Buck L, Axel R. Cell, 1991, 65, 175-187. 2. Thomas-Danguin T, Sinding C, et al. Front. Psychol., 2014, 5, 504. 3. Le Berre E, Thomas-Danguin T, et al. Chem. Senses, 2008, 33, 193-199. 4. Ma LM, Qiu Q, et al. Proc. Natl. Acad. Sci. U. S. A., 2012, 109, 5481-5486. 5. Poivet E, Tahirova N, et al. Sci. Adv., 2018, 4, eaao6086. 6. Tromelin A, Chabanet C, et al. Flavour Frag. J., 2018, 33, 106-126. 7. Flavor-Base 9th Ed. (2013). Leffingwell & Associates, http://www.leffingwell.com/flavbase.htm