Specific Odor Research Articles

Enantioselective Detection of Gaseous Odorants with Peptide-Graphene Sensors Operating in Humid Environments.

Replicating the sense of smell presents an ongoing challenge in the development of biomimetic devices. Olfactory receptors exhibit remarkable discriminatory abilities, including the enantioselective detection of individual odorant molecules. Graphene has emerged as a promising material for biomimetic electronic devices due to its unique electrical properties and exceptional sensitivity. However, the efficient detection of nonpolar odor molecules using transistor-based graphene sensors in a gas phase in environmental conditions remains challenging due to high sensitivity to water vapor. This limitation has impeded the practical development of gas-phase graphene odor sensors capable of selective detection, particularly in humid environments. In this study, we address this challenge by introducing peptide-functionalized graphene sensors that effectively mitigate undesired responses to changes in humidity. Additionally, we demonstrate the significant role of humidity in facilitating the selective detection of odorant molecules by the peptides. These peptides, designed to mimic a fruit fly olfactory receptor, spontaneously assemble into a monomolecular layer on graphene, enabling precise and specific odorant detection. The developed sensors exhibit notable enantioselectivity, achieving a remarkable 35-fold signal contrast between d- and l-limonene. Furthermore, these sensors display distinct responses to various other biogenic volatile organic compounds, demonstrating their versatility as robust tools for odor detection. By acting as both a bioprobe and an electrical signal amplifier, the peptide layer represents a novel and effective strategy to achieve selective odorant detection under normal atmospheric conditions using graphene sensors. This study offers valuable insights into the development of practical odor-sensing technologies with potential applications in diverse fields.

Smelling TNT: Trends of the Terminal Nerve.

There is very little knowledge regarding the terminal nerve, from its implications in the involvement and pathogenesis of certain conditions, to its embryological origin. With this review, we try to summarize the most important evidence on the terminal nerve, aiming to clarify its anatomy and the various functions attributed to it, to better interpret its potential involvement in pathological processes. Recent studies have also suggested its potential role in the control of human reproductive functions and behaviors. It has been hypothesized that it plays a role in the unconscious perception of specific odors that influence autonomic and reproductive hormonal systems through the hypothalamic-pituitary-gonadal axis. We used the PubMed database and found different articles which were then selected independently by three authors. We found 166 articles, of which, after careful selection, only 21 were analyzed. The terminal nerve was always thought to be unimportant in our body. It was well studied in different types of animals, but few studies have been completed in humans. For this reason, its function remains unknown. Studies suggest a possible implication in olfaction due to the anatomical proximity with the olfactive nerve. Others suggest a more important role in reproduction and sexual behaviors. New emerging information suggests a possible role in Kallmann syndrome and COVID-19.

Localized Expression of Olfactory Receptor Genes in the Olfactory Organ of Common Minke Whales.

Baleen whales (Mysticeti) possess the necessary anatomical structures and genetic elements for olfaction. Nevertheless, the olfactory receptor gene (OR) repertoire has undergone substantial degeneration in the cetacean lineage following the divergence of the Artiodactyla and Cetacea. The functionality of highly degenerated mysticete ORs within their olfactory epithelium remains unknown. In this study, we extracted total RNA from the nasal mucosae of common minke whales (Balaenoptera acutorostrata) to investigate ORs' localized expression. All three sections of the mucosae examined in the nasal chamber displayed comparable histological structure. However, the posterior portion of the frontoturbinal region exhibited notably high OR expression. Neither the olfactory bulb nor the external skin exhibited the expression of these genes. Although this species possesses four intact non-class-2 ORs, all the ORs expressed in the nasal mucosae belong to class-2, implying the loss of aversion to specific odorants. These anatomical and genomic analyses suggest that ORs are still responsible for olfaction within the nasal region of baleen whales, enabling them to detect desirable scents such as prey and potential mating partners.

Flavor Chemical Research on Different Bee Pollen Varieties Using Fast E-Nose and E-Tongue Technology.

Bee pollen, derived from various plant sources, is renowned for its nutritional and bioactive properties, aroma, and taste. This study examined the bee pollen with the highest yield in China obtained from four plant species, namely Brassica campestris (Bc), Nelumbo nucifera (Nn), Camellia japonica (Cj), and Fagopyrum esculentum (Fe), using fast e-nose and e-tongue technology to analyze their flavor chemistry. Results showed substantial differences in scent profiles among the varieties, with distinct odor compounds identified for each, including n-butanol, decanal, and ethanol, in Bc, Nn, and Cj, respectively. The primary odorants in Fe consist of E-2-hexen-1-ol and (Z)-3-hexen-1-ol. Additionally, e-tongue analysis revealed seven distinct tastes in bee pollen samples: AHS, PKS, CTS, NMS, CPS, ANS, and SCS, with variations in intensity across each taste. The study also found correlations between taste components and specific odor compounds, providing insights for enhancing product quality control in bee pollen processing.

Methods of processing the stomachs of cattle

Currently, the meat industry has accumulated considerable experience in the efficient processing of cattle byproducts. But the share of their use for food purposes remains low. This concerns, first of all, the treatment of the multicameral stomach of cattle. The future direction of scientific research is the use of these by-products in full. This article discusses the technological processes of processing by-products of cattle (tripe and reticulated tripe) using waste from the dairy industry. One of the concrete and effective ways to solve the problem is to carry out the processes of biotechnological processing of cattle. To reduce the time of heat treatment and eliminate the specific odor characteristic of the scar, and to reduce the mechanical strength, a technology for processing cattle rumen with whey is proposed. The nutritional value and consumer properties of cattle by-products (rumen, reticulated rumen) have been investigated as a source of food raw materials, the prospects of use are assessed. In this work, the possibility of treating the scar of cattle with serum was investigated. Studies of the physico-chemical composition and biological value of by-products have shown a high content of proteins and minerals, amino acids in the abdominal and retina. A solution of whey is recommended for softening and cleansing the rumen of cattle and reticulated cattle. Processing of collagen-containing raw materials with biologically active substances using whey microorganisms should be recognized as one of the promising areas.

A potential link between aromatics-induced oviposition repellency behaviors and specific odorant receptor of Aedes albopictus.

The Asian tiger mosquito, Aedes albopictus, is a competent vector for the spread of several viral arboviruses including dengue, chikungunya, and Zika. Several vital mosquito behaviors linked to survival and reproduction are primarily dependent on a sophisticated olfactory system for semiochemical perception. However, a limited number of studies has hampered our understanding of the relationship between the A. albopictus acute olfactory system and the complex chemical world. Here, we performed a qRT-PCR assay on antennae from A. albopictus of differing sex, age and physiological states, and found that AalbOr10 was enriched in blood-fed female mosquitoes. We then undertook single sensillum recording to de-orphan AalbOr10 using a panel of physiologically and behaviorally relevant odorants in a Drosophila 'empty neuron' system. The results indicated that AalbOr10 was activated by seven aromatic compounds, all of which hampered egg-laying in blood-fed mosquitoes. Furthermore, using a post-RNA interference oviposition assay, we found that reducing the transcript level of AalbOr10 affected repellent activity mediated by 2-ethylphenol at low concentrations (10-4 vol/vol). Computational modeling and molecular docking studies suggested that hydrogen bonds to Y68 and Y150 mediated the interaction of 2-ethylphenol with AalbOr10. We reveal a potential link between aromatics-induced oviposition repellency behaviors and a specific odorant receptor in A. albopictus. Our findings provide a foundation for identifying active semiochemicals for the monitoring or controlling of mosquito populations. © 2024 Society of Chemical Industry.

Prospects of the development and harmonization of hygienic standardization taking into account the risk of odour in the ambient air

Introduction. The presence of a specific odour in the ambient air in the areas where various enterprises are located with formal compliance with environmental legislation indicates the need to update the methodology of hygienic standardization of odourous substances.
 The purpose of the work is to analyze modern methods of the establishment of standards for odourous complex multicomponent mixtures of substances in the atmospheric air and substantiate ways to harmonize them in this field of knowledge.
 Materials and methods. The paper systematizes existing approaches to regulating the quality of atmospheric air in areas where odourous emissions sources are located, taking into account certain provisions of regulatory and methodological documents, publications on approaches, and criteria for quantitative sanitary and hygienic assessment of the quality of the environment and public health, as well as the authors’ long-term experience in this field.
 Results. The basic principles of hygienic standardization of the permissible content of odorous mixtures of substances in the atmospheric air taking into account their odour are formulated. The substantiation of hygienic standards is carried out with the allocation of substances identified as priority (indicator), based on the results of studying the production technology and the formation of emissions, olfactory properties of the mixture under experimental conditions, with the possibility of monitoring the established standard in atmospheric air by certified instrumental methods of analysis.
 Limitations. The limitations of the study are due to the fact that this article does not fully reflect the issues of the development of the entire atmospheric air quality management system taking into account the risk of odour outside the focus of this work, which will be covered in the preparation of the following articles.
 Conclusion. The ongoing process of harmonization of domestic and foreign approaches used in hygienic standardization including the field of regulation of atmospheric air pollution by specific odours makes it necessary to significantly expand approaches to the issues of rationing and assessment of environmental pollution by complex multicomponent emissions of odour-source enterprises taking into account modern experience.

GC-MS and ATR-FTIR Spectroscopy Coupled with Chemometric Analysis for Detection and Quantification of White Turmeric (Curcuma zedoaria) Essential Oils Adulteration.

<b>Background and Objective:</b> White turmeric essential oil (WTEO) is known to have high commercial value since it has been used to improve immunological function, increase blood circulation, ease toxin clearance and stimulate digestion. However, there is no standard to regulate the specific characteristics of white turmeric essential oil. Therefore, the objective of this research was to develop an analytical technique for WTEO authentication from vegetable oils, namely palm oil (PO), coconut oil (VCO) and soybean oil (SO), using FTIR spectroscopy and chemometrics, as well as GC-MS spectroscopy. <b>Materials and Methods:</b> The WTEO was obtained by hydrodistillation method. Pure WTEO and vegetable oils were scanned in the MIR region (4000-650 cm<sup>1</sup>) of FTIR spectroscopy and the spectra were further analyzed using chemometrics. <b>Results:</b> The extraction yielded 0.103% v/w WTEO, a dark purple color with a specific pungent odor. Discriminant analysis separated pure WTEO and adulterated WTEO with 100% accuracy at wave numbers 4000-650 cm<sup>1</sup>. The best PLS regressions to quantify SO, VCO, PO and concentration in WTEO were at wave numbers 4000-1100, 1400-1050 and 2100-650 cm<sup>1</sup>, respectively. <b>Conclusion:</b> The FTIR and chemometrics combination effectively authenticates white turmeric essential oil from any possible adulterants, such as vegetable oil.

Experience-Dependent Remodeling of Juvenile Brain Olfactory Sensory Neuron Synaptic Connectivity in an Early-Life Critical Period.

Early-life olfactory sensory experience induces dramatic synaptic glomeruli remodeling in the Drosophila juvenile brain, which is experientially dose-dependent, temporally restricted, and transiently reversible only in a short, well-defined critical period. The directionality of brain circuit synaptic connectivity remodeling is determined by the specific odorant acting on the respondent receptor class of olfactory sensory neurons. In general, each neuron class expresses only a single odorant receptor and innervates a single olfactory synaptic glomerulus. In the Drosophila genetic model, the full array of olfactory glomeruli has been precisely mapped by odorant responsiveness and behavioral output. Ethyl butyrate (EB) odorant activates Or42a receptor neurons innervating the VM7 glomerulus. During the early-life critical period, EB experience drives dose-dependent synapse elimination in the Or42a olfactory sensory neurons. Timed periods of dosed EB odorant exposure allow investigation of experience-dependent circuit connectivity pruning in juvenile brain. Confocal microscopy imaging of antennal lobe synaptic glomeruli is done with Or42a receptor-driven transgenic markers that provide quantification of synapse number and innervation volume. The sophisticated Drosophila genetic toolkit enables the systematic dissection of the cellular and molecular mechanisms mediating brain circuit remodeling.

Exploring the functional profiles of odorant binding proteins crucial for sensing key odorants in the new leaves of coconut palms in Rhynchophorus ferrugineus

The red palm weevil (RPW), Rhynchophorus ferrugineus (Curculionidae: Coleoptera) is a highly destructive global pest of coconut trees, with a preference for laying its eggs on new leaves. Females can identify where to lay eggs by using their sense of smell to detect specific odorants found in new leaves. In this study, we focused on the two odorants commonly found in new leaves by GC–MS: trans, trans-2,4-nonadienal and trans-2-nonenal. Our behavioral assays demonstrated a significant attraction of females to both of these odorants, with their electrophysiological responses being dose-dependent. Furthermore, we examined the expression patterns induced by these odorants in eleven RferOBP genes. Among them, RferOBP3 and RferOBP1768 exhibited the most significant and simultaneous upregulation. To further understand the role of these two genes, we conducted experiments with females injected with OBP-dsRNA. This resulted in a significant decrease in the expression of RferOBP3 and RferOBP1768, as well as impaired the perception of the two odorants. A fluorescence competitive binding assay also showed that both RferOBPs strongly bound to the odorants. Additionally, sequence analysis revealed that these two RferOBPs belong to the Minus-C family and possess four conserved cysteines. Molecular docking simulations showed strong interactions between these two RferOBPs and the odorant molecules. Overall, our findings highlight the crucial role of RferOBP3 and RferOBP1768 in the olfactory perception of the key odorants in coconut palm new leaves. This knowledge significantly improves our understanding of how RPW females locate sites for oviposition and lays the foundation for future research on the development of environmentally friendly pest attractants.

Females smell differently: characteristics and significance of the most common olfactory sensilla of female silkmoths.

In the silkmoth Bombyx mori, the role of male sensilla trichodea in pheromone detection is well established. Here we study the corresponding female sensilla, which contain two olfactory sensory neurons (OSNs) and come in two lengths, each representing a single physiological type. Only OSNs in medium trichoids respond to the scent of mulberry, the silkworm's exclusive host plant, and are more sensitive in mated females, suggesting a role in oviposition. In long trichoids, one OSN is tuned to (+)-linalool and the other to benzaldehyde and isovaleric acid, both odours emitted by silkworm faeces. While the significance of (+)-linalool detection remains unclear, isovaleric acid repels mated females and may therefore play a role in avoiding crowded oviposition sites. When we examined the underlying molecular components of neurons in female trichoids, we found non-canonical co-expression of Ir8a, the co-receptor for acid responses, and ORco, the co-receptor of odorant receptors, in long trichoids, and the unexpected expression of a specific odorant receptor in both trichoid sensillum types. In addition to elucidating the function of female trichoids, our results suggest that some accepted organizational principles of the insect olfactory system may not apply to the predominant sensilla on the antenna of female B. mori.

Use of dandelion root in functional bread technology

Prevention of nutritional diseases with the help of functional foods remains relevant. Therefore, the development of food technology using raw materials that contribute to the formation of functional properties is relevant and has scientific and practical significance. The object of the research was every day product, i.e. bread made from premium wheat flour. In order to form functional properties non-traditional plant raw materials were used to enrich bread – dandelion root, characterized by a high content of prebiotic substance – inulin. The purpose of the research was to substantiate the creation of bakery products for a wide range of consumers, enriched with wild plant materials with functional properties. Organoleptic evaluation was carried out in accordance with GOST R 53161-2008; dietary fiber content according to GOST R 54014-2010; vitamins according to the General Pharmacopoeia. 1.2.3.0017.15. As a result of laboratory baking, experimental samples of bread were obtained from premium wheat flour containing dandelion root powder in the recipe in amounts of 5, 10 and 15%. An organoleptic assessment of the quality of the prototypes made it possible to justify the choice of a bread recipe made from wheat flour with the addition of dandelion root powder in an amount of 5%. A larger amount contributed to the appearance of a bitter taste, a specific herbal odor and the formation of uneven porosity of bread and dense crumb. Adding dandelion root powder to the recipe for bread made from wheat flour helps to increase the content of dietary fiber in the finished product by an average of 1.5 times for every 5% of added powder, as well as increasing the content of vitamins B1, B2 and B5. The developed type of bread can be produced at any bakery, as well as public catering enterprise, which will help expand the range of functional food products.

Binding Interaction Between Lauric Acid and Cluster of Differentiation 36 Underpinned by a Fluorescence- Intensifying Assay.

Cluster of differentiation 36 (CD36) is a scavenger receptor expressed in various vertebrate cells that contains diverse ligands, including long-chain fatty acids. This receptor has recently been suggested as a captor of specific volatile odorants (e.g., aliphatic acetates) in the mammalian nasal epithelium. This study used a fluorescence-intensifying assay to produce the first evidence that lauric acid, an odorous fatty acid, directly binds to CD36. This expansion of the repertoire of volatile ligands supports potential applications for nasal CD36. Our present findings could promote future research aimed at understanding the mechanisms of fatty acid interactions with CD36.

Effects of genetics on odor perception: Can a quick smell test effectively screen everyone?

SCENTinel, a rapid smell test designed to screen for olfactory disorders, including anosmia (no ability to smell an odor) and parosmia (distorted sense of smell), measures 4 components of olfactory function: detection, intensity, identification, and pleasantness. Each test card contains one of 9 odorant mixtures. Some people born with genetic insensitivities to specific odorants (i.e. specific anosmia) may fail the test if they cannot smell an odorant but otherwise have a normal sense of smell. However, using odorant mixtures has largely been found to prevent this from happening. To better understand whether genetic differences affect SCENTinel test results, we asked genetically informative adult participants (twins or triplets, N = 630; singletons, N = 370) to complete the SCENTinel test. A subset of twins (n = 304) also provided a saliva sample for genotyping. We examined data for differences between the 9 possible SCENTinel odors; effects of age, sex, and race on SCENTinel performance, test-retest variability; and heritability using both structured equation modeling and SNP-based statistical methods. None of these strategies provided evidence for specific anosmia for any of the odors, but ratings of pleasantness were, in part, genetically determined (h2 = 0.40) and were nominally associated with alleles of odorant receptors (e.g. OR2T33 and OR1G1; P < 0.001). These results provide evidence that using odorant mixtures protected against effects of specific anosmia for ratings of intensity but that ratings of pleasantness showed effects of inheritance, possibly informed by olfactory receptor genotypes.

Emerging trends in metal oxide-based electronic noses for healthcare applications: a review.

An electronic nose (E-nose) is a technology fundamentally inspired by the human nose, designed to detect, recognize, and differentiate specific odors or volatile components in complex and chaotic environments. Comprising an array of sensors with meticulously designed nanostructured architectures, E-noses translate the chemical information captured by these sensors into useful metrics using complex pattern recognition algorithms. E-noses can significantly enhance the quality of life by offering preventive point-of-care devices for medical diagnostics through breath analysis, and by monitoring and tracking hazardous and toxic gases in the environment. They are increasingly being used in defense and surveillance, medical diagnostics, agriculture, environmental monitoring, and product validation and authentication. The major challenge in developing a reliable E-nose involves miniaturization and low power consumption. Various sensing materials are employed to address these issues. This review presents the key advancements over the last decade in E-nose technology, specifically focusing on chemiresistive metal oxide sensing materials. It discusses their sensing mechanisms, integration into portable E-noses, and various data analysis techniques. Additionally, we review the primary metal oxide-based E-noses for disease detection through breath analysis. Finally, we address the major challenges and issues in developing and implementing a portable metal oxide-based E-nose.

Exploring the Molecularity of the Odor and Taste Perceptions of “Brown”: A Computational Approach

We have developed a methodology that seeks to associate the molecularity of compounds with the perceptions of specific odor or taste. This methodology goes beyond gross structural features for a molecule: aromatic or aliphatic rings, lengths of the aliphatic straight chains, or the nature and variation in the functional groups. We target specific atom pairs–bonded or remote–within the smell and taste molecule that have structural-electronic features that are reproducible across molecules that elicit similar smell and taste responses. We represent the “structure” of the atom pair by its interatomic distance. The “electronic” aspects are represented by Nuclear Magnetic Resonance (NMR) chemical shifts that uniquely define the electronic environments of the atoms. We used quantum chemistry calculations and the density functional theory (DFT) to determine the chemical shifts and interatomic distances (through the Z-matrix). We used this methodology to process 19 molecules that elicited the smell of “brown,” and 18 molecules that elicited the taste of “brown.” These molecules were accessed through odor and taste indices from the GoodScentsCompany resource (https://www.thegoodscentscompany.com/). These “brown” odorants and tastants elicited other associated smells and tastes. We identified and illustrated specific bond pairs that elicited different smells and tastes. While smell and taste are intrinsically related, our studies also show atom pairs that are likely responsible exclusively for smell and taste, as well as pairs that elicit both. This work will be impactful in the domain of drug design in the pharmaceutical industry, in addition to enhancing our understanding of how a chemical catalyzes the process that results in chemosensory perception.

Odorant detection in a locust exhibits unusually low redundancy

Olfactory coding, from insects to humans, is canonically considered to involve considerable across-fiber coding already at the peripheral level, thereby allowing recognition of vast numbers of odor compounds. We show that the migratory locust has evolved an alternative strategy built on highly specific odorant receptors feeding into a complex primary processing center in the brain. By collecting odors from food and different life stages of the locust, we identified 205 ecologically relevant odorants, which we used to deorphanize 48 locust olfactory receptors via ectopic expression in Drosophila. Contrary to the often broadly tuned olfactory receptors of other insects, almost all locust receptors were found to be narrowly tuned to one or very few ligands. Knocking out a single receptor using CRISPR abolished physiological and behavioral responses to the corresponding ligand. We conclude that the locust olfactory system, with most olfactory receptors being narrowly tuned, differs from the so-far described olfactory systems.

Everything smells like poo, landfill, and rotten food”: A retrospective case report using Clinical Emotional Freedom Techniques (EFT) for parosmia following COVID-19

Abstract: Parosmia is a disorder of scent that has affected millions of people worldwide following their recovery from COVID-19. Parosmia post COVID-19 can be long-term and has a negative impact on quality of life. Despite this there is limited evidence for effective treatment strategies. This retrospective case report details the use of Clinical Emotional Freedom Techniques (EFT) to address parosmia following COVID-19 with a single client over three sessions. The sessions addressed specific food, drink, and odors that were having a major negative impact on the client’s quality of life, psychological well-being, physical health, weight, and relationships. By the end of the three sessions, the client was able to tolerate certain scents and eat foods that the client selected to tap on. The client’s quality of life improved to the point where she was able to eat, go out to restaurants, socialize, and ultimately return to work. Whether EFT can be successfully applied to other people experiencing parosmia following COVID-19 or parosmia caused by other conditions is not clear and requires further research. Keywords: parosmia, sense of smell, COVID-19, Clinical Emotional Freedom Techniques, EFT

ОПЫТ ВЫДЕЛЕНИЯ ЛЮТЕОЛИНА ИЗ ТРАВЫ ORIGANUM VULGARE

Due to economic conditions, today the purchase of reference materials from abroad is expensive, and domestic production is low and also expensive. The purpose of this study is to develop a method for isolating luteolin from Origanum vulgare (oregano). The raw material for this work was a sample of oregano herb, collected in 2022 in the Perm krai. The herb extract was obtained with 60% ethyl alcohol. The extract is a dark greenish-brown crystalline powder with a specific aromatic odor. Chloroform and hexane were used to purify the dry extract from nonpolar compounds. Diethyl ether was used to extract luteolin. This choice was justified by the fact that chloroform and hexane well remove non-polar, lipophilic compounds contained in the dry extract, and methoxylated aglycone flavonoids can also dissolve in chloroform. Diethyl ether was chosen because only aglycone flavonoids are soluble in it. Separated using a solvent system, butanol – acetic acid – water (4:1:2). The equipment used was a chromatographic column with a diameter of 10 mm, a vacuum pump. In the course of the study, we proposed the following scheme for the separation of substances, divided into 3 stages: 1st stage is purification of dry extract from non-polar (lipophilic) compounds; 2nd stage is extraction of aglycone flavonoid (luteolin) into diethyl ether; 3rd stage is separation of substances that passed into diethyl ether on a chromatographic column. According to the quality control of the progress of work, namely TLC and NMR spectroscopy, one can note the likely suitability of the developed method for the isolation of luteolin from the extract of oregano herb.

Physical Confounding Factors Affecting Gas Sensors Response: A Review on Effects and Compensation Strategies for Electronic Nose Applications

Electronic noses (e-noses) are devices based on combining different gas sensors’ responses to a given sample for identifying specific odor fingerprints. In recent years, this technology has been considered a promising novel tool in several fields of application, but several issues still hamper its widespread use. This review paper describes how some physical confounding factors, such as temperature, humidity, and gas flow, in terms of flow direction and flow rate, can drastically influence gas sensors’ responses and, consequently, e-nose results. Among the software and hardware approaches adopted to address such issues, different hardware compensation strategies proposed in the literature were critically analyzed. Solutions related to e-nose sensors’ modification, design and readout, sampling system and/or chamber geometry design were investigated. A trade-off between the loss of volatile compounds of interest, the decrease of sensors’ sensitivity, and the lack of fast responses need to be pointed out. The existing body of knowledge suggests that the e-nose design needs to be highly tailored to the target application to exploit the technology potentialities fully and highlights the need for further studies comparing the several solutions proposed as a starting point for the application-driven design of e-nose-based systems.