Odour serves as a long-lasting cue or signal that animals with developed olfactory systems rely on heavily for communication. The ability to discriminate a particular odour modulates the social ...behaviours of a receiver. Animals investigate odours from unfamiliar conspecifics more than they do those from familiar ones, either as a means of choosing a mate or to avoid competition. The African painted dog, Lycaon pictus, which is known for its sophisticated sociality and extremely strong body odour, appears to rely heavily on odour communication. However, empirical research on odour-related behaviour in this species is limited. We investigated whether captive African painted dogs discriminated between their own odours and those of conspecifics, between familiar and unfamiliar conspecifics, and between the sexes. Our behavioural experiments showed that subjects investigated other conspecifics’ odours longer than they did their own odour. Detailed analysis showed that they spent more time investigating unfamiliar conspecifics than familiar ones. The effect of donor sex on the investigation duration was not significant when comparing odours from males and females. However, the investigation time of odours from females was longer than that of their own, with no such difference observed between odours from males and their own. This study is the first to demonstrate that the African painted dog is capable of discriminating its own odour from the odours of conspecifics, between familiar and unfamiliar animals and between the sexes. This research provides fundamental knowledge of odour communication in this species.
•This is the first study on African painted dogs' odour discrimination.•Subjects did not discriminate between their own and unfamiliar odours.•Donor or subject sex did not affect investigation time.
Odorous gases emitted from landfills have always been a public concern, but studies evaluating the odour contribution and the correlation between the odour concentrations are limited. The objectives ...of this study were to assess the odour contribution and to correlate the measured odour concentration COD with the calculated odour concentration SOAV, which was calculated as sum of individual odour activity value (OAV). Odorous air samples from a landfill in Beijing were collected seasonally and measured by both gas chromatography and an olfactometer. Different from previous studies, we measured the odour threshold of 51 detected compounds using a uniform methodology to minimize the imprecision of citing odour threshold from disparate literature. The odour threshold is used to convert the individual chemical concentration into the OAV, which is used as a surrogate of the odour concentration. Evaluation of the OAV revealed that hydrogen sulfide (65.9%), dimethyl sulfide (14.4%) and trimethylamine (8.6%) contributed the most to the odour at the landfill. Moreover, the correlation between the calculated odour concentration SOAV and the measured odour concentration COD resulted in a linear regression equation of COD = 6.28 SOAV (r = 0.914, n = 24, p < 0.01). Based on the scaling factor K = 6.28, the average ratio of calculated odour concentration to measured odour concentration could be improved from less than 0.2 to 1.1. By the calibration of the calculated odour concentration SOAV, it is possible to use continuous measurements of chemical concentrations to derive odour concentration for this site for monitoring purposes.
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•Odour threshold of 51 common compounds was measured by a dynamic olfactometer.•Calculated SOAV correlated good with measured odour concentration (r = 0.914).•Scaling factor K improved the precision of calculating odour concentration to 110% .•H2S (65.9%), DMS and TMA contributed the most to the odour in the landfill.
In the drinking water and air pollution fields, odour quality characterisation and intensity of each odour characteristic needs to be developed to evaluate the causes of the odours present. Drinking ...water quality characterisation has matured to the point where an "odour wheel" is described and the primary chemicals producing the odour are known and therefore a potential treatment can be defined from the odours reported. Sufficient understanding of the types of odorous compounds that can arise from wastewater and compost treatment processes and odours in the urban environment are starting to emerge. This article presents the anatomy of the odour wheels. It is hoped that the foundation of odour wheels will evolve as odour quality data are reported and linked with chemical causation. The compost and urban odour wheels are presented in print for the first time.
Continuous odour measurements both of emissions as well as ambient concentrations are seldom realised, mainly because of their high costs. They are therefore often substituted by concentration ...measurements of odorous substances. Then a conversion of the chemical concentrations C (mg m−3) into odour concentrations COD (ouE m−3) and odour intensities OI is necessary. Four methods to convert the concentrations of single substances to the odour concentrations and odour intensities of an odorous mixture are investigated: (1) direct use of measured concentrations, (2) the sum of the odour activity value SOAV, (3) the sum of the odour intensities SOI, and (4) the equivalent odour concentration EOC, as a new method. The methods are evaluated with olfactometric measurements of seven substances as well as their mixtures. The results indicate that the SOI and EOC conversion methods deliver reliable values. These methods use not only the odour threshold concentration but also the slope of the Weber–Fechner law to include the sensitivity of the odour perception of the individual substances. They fulfil the criteria of an objective conversion without the need of a further calibration by additional olfactometric measurements.
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•Concentration of odorous substances as surrogate for odour concentration/intensity.•Comparison of conversion methods with various degrees of complexity.•Model evaluation by seven VOCs: 23 binary mixtures and 5 mixtures of 7 substances.•Model input: odour threshold concentration and the slope of the Weber–Fechner law.•No further calibration by olfactometric measurements necessary.
It has been reported that a distinct ‘old person smell’ can develop with advancing age, however, this odour has not yet been sufficiently described in previous research. Sensory evaluation by a ...trained panel might be useful to describe alterations with age in body odour (BO). To evaluate the alterations and achieve first insights into the ‘old person smell’, this pilot study determined the odour profiles of BO samples from both a younger and an older age group with a trained panel. In addition, we aimed to assess whether the panellists can recognize the age group based on the smell of the BO samples. Eight younger (20–28 years) and eight older (80–83 years) participants sampled their BO by wearing a cotton T‐shirt for one night. The samples were sensorially evaluated by a trained panel, including ratings of total intensity and pleasantness. Additionally, an age labelling task was performed as a forced‐choice decision. Results revealed that the odour profiles of the BO samples were very similar for both age groups. Nevertheless, trained panellists were able to predict the age group with significantly higher accuracy (p = .042) than expected by chance (61% mean accuracy over all panellists). Furthermore, a linear support vector machine (SVM) classifier achieved an average accuracy of 69%. This finding indicates that the age of a person affects the BO, though it is not reflected in significantly distinct odour profiles.
Trained panellists established odour profiles for axillary body odour samples donated by younger and older persons and were able to predict the age group with significantly higher accuracy than expected by chance. By training a linear SVM classifier based on the trained panellists' ratings, higher accuracy was achieved. This finding indicates that hints towards the age of the body odour donor were present in the body odour samples.
The olfactory sense is a particularly challenging domain for cognitive science investigations of perception, memory, and language. Although many studies show that odors often are difficult to ...describe verbally, little is known about the associations between olfactory percepts and the words that describe them. Quantitative models of how odor experiences are described in natural language are therefore needed to understand how odors are perceived and communicated. In this study, we develop a computational method to characterize the olfaction-related semantic content of words in a large text corpus of internet sites in English. We introduce two new metrics: olfactory association index (OAI, how strongly a word is associated with olfaction) and olfactory specificity index (OSI, how specific a word is in its description of odors). We validate the OAI and OSI metrics using psychophysical datasets by showing that terms with high OAI have high ratings of perceived olfactory association and are used to describe highly familiar odors. In contrast, terms with high OSI have high inter-individual consistency in how they are applied to odors. Finally, we analyze Dravnieks’s (1985) dataset of odor ratings in terms of OAI and OSI. This analysis reveals that terms that are used broadly (applied often but with moderate ratings) tend to be olfaction-unrelated and abstract (e.g., “heavy” or “light”; low OAI and low OSI) while descriptors that are used selectively (applied seldom but with high ratings) tend to be olfaction-related (e.g., “vanilla” or “licorice”; high OAI). Thus, OAI and OSI provide behaviorally meaningful information about olfactory language. These statistical tools are useful for future studies of olfactory perception and cognition, and might help integrate research on odor perception, neuroimaging, and corpus-based linguistic models of semantic organization.
Longevity of odour memories, particularly those acquired during early development, has been documented in a wide range of taxa. Here, we report that kittens of the domestic cat retained a memory into ...adult life of their mother´s body odour experienced before weaning. Kittens from 15 litters were tested when permanently separated from their mother at weaning on postnatal week 8, and tested again when 4 and 6 months and over 1 year of age. When presented with a simultaneous three-way choice between body odour of their own mother, of an unknown female of similar reproductive condition and a blank stimulus, weaning-age kittens sniffed the cotton swab with the odour of an unknown female longer. This preference, however, changed when as adults the subjects sniffed the cotton swab with their own mother’s odour longer. We conclude that kittens form a long-lasting memory of the body odour of their mother, and by implication, that mothers retain an individual odour signature sufficiently stable across age and changes in their reproductive state to be distinguishable by their adult offspring. What this means in functional or cognitive terms is not yet clear. Does such “recognition” have a specific biological function and a specific cognitive representation? Or is it rather part of a more general phenomenon well known in (human) olfaction of odours that are familiar generally being judged more pleasant, and that might then influence olfactory-guided behaviour in a variety of contexts?
This work proposes an odour‐induced affect scale for use in the cosmetic industry that relies on the approach that produced the UniGEOS, a universal odour‐related emotional scale from the Swiss ...Center for Affective Sciences. The Natura Emotion and Odor Scale (NEOS) was built on experiments conducted with a larger set of participants (491) and a set of 35 scents that combine seven commercial perfumes from Natura & Co cosmetic company with 28 odours from different olfactory classes important for the cosmetic industry. The results showed the stability of 60 Emotion‐Related terms in Brazilian Portuguese split into five emotion‐related dimensions: Romance, Attention, Energy, Well‐being and Negative feelings. The association of the scents evoking these five dimensions has direct implications in the design of new products.
Résumé
Ce travail propose une échelle d'affect induite par des odeurs passible d'être utilisée dans l'industrie cosmétique. Cette échelle s'appuie sur l'approche qui a produit l'UniGEOS, une échelle affective universelle liée aux odeurs du Swiss Center for Affective Sciences. L'échelle Natura Emotion and Odor Scale (NEOS) a été construite sur la base d'expériences menées avec un plus grand nombre de participants (491) et un ensemble de 35 arômes combinant sept parfums commerciaux de la compagnie Natura & Co avec 28 odeurs de différentes classes olfactives importantes pour l'industrie cosmétique. Les résultats ont montré la stabilité de 60 termes liés aux émotions en portugais brésilien, répartis en cinq dimensions liées aux émotions : Romance, Attention, Énergie, Bien‐être et Sentiments négatifs. L'association des arômes évoquant ces cinq dimensions a des implications directes dans la conception de nouveaux produits.
The study highlights the relationship between emotions and olfactory classes, providing valuable insights for the design of products in the cosmetic industry and the development of emotionally induced experiences.
Summary
Thermal reactions affect flavour, but how different thermal reactions influence the flavour of cooked soup has rarely been investigated. Herein, the effect of heat treatment (0–50 min) at ...different temperatures (120, 140 and 160 °C) on
Ruditapes philippinarum
soup was studied. The acceptable heating of
Ruditapes philippinarum
soup was assigned at 140 °C for 30 min by human sensory evaluation and compound analysis. In addition, the detailed relationship between the formation of key volatile compounds and heating temperature was revealed by partial least squares discriminant analysis (PLS‐DA) and the odour coding method. A total of 28 key volatile compounds were selected according to the results of variables important in the projection (VIP) and odour activity value (OAV). Whereas 3‐ethyl‐2,5‐dimethyl pyrazine and 2‐heptylfuran were the most important volatiles produced only in the thermal reaction at 140 °C and associated with cocoa and roasted nut odours. These results indicated the relationship between thermal reactions and flavour formation. The odour coding obtained from OAV could be as a reference benchmark for heating seafood soup products.
The different psychophysical studies carried out on the qualitative properties of simple and complex mixtures are reviewed. Many of the early studies conducted on binary mixtures have been ...reprocessed and compared by using similar representations and data treatments. Results confirm that the intensity ratio of the mixture constituents is the main driver of quality, so that the most intense compound tends to dominate the overall odour of the mixture. In contrast to what was previously thought, in most binary mixtures one of the components is more powerful than the other, dominating the overall odour of the mixture in a larger range of mixture compositions. In some but not all subsets of odorants, a clear hierarchy in their relative dominance has been observed. Pleasantness, complexity or freshness arise as major but not unique factors determining the order of dominance. Steven's coefficients could also have an influence, while polarity and temporal processing rates seem to have no influence. Competitive interactions at receptor level seem to play a limited role. In some aroma pairs, a small change in odour composition (26%) provokes the shift in odour dominance, while in others a 500% intensity change may be required for the shift. There is sound evidence that one or several odour descriptors of minor non‐dominant odour components can be detected in the odour of the mixture. In more complex mixtures, results support the fact that some odorants in specific odour backgrounds are detected more easily than others. The most frequent qualitative outcome of a complex mixture will be an average of the odour qualitative descriptors of the odour chemicals present in the mixture, except when the mixture contains within its constituents a series of odour chemicals at specific intensity ratios able to trigger a configurational recognition process ending with the recognition of a different odour object. Key challenges for the modelling of the aroma properties of complex systems are enunciated.
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