Odor Value Research Articles

Powerful Patina: The Value of Odors in a Tibetan Buddhist Temple

ABSTRACT In the past decades, attention towards a more sensory perception in the arts and architecture has gained momentum and concerns a variety of disciplines. Nonetheless, hands-on conservation efforts still overwhelmingly concentrate on the visual qualities and values of places. In the following article, I present a case study of a Tibetan–Buddhist temple in Ladakh/India that empirically examines questions of value as they extend to the idea of patina found on wall paintings inside the temple produced by the burning of butter lamps. The layer of soot which obscures these centuries-old wall paintings has particular olfactory qualities. The paper draws from my professional and personal experience as art conservator working with an NGO from 2004 until 2014. It is a methodological re-thinking of our original conservation approach through the framework of Alois Riegl's value model applied to olfactory perceptions of patina. Examined are the meaning of odors concerning heritage values, memory, and the formation of identity. Odors are site-specific, therefore, conservation work at heritage sites needs to include the documentation and value assessment of their olfactory qualities to determine the impact a removal of patina may have on stakeholder communities.

Disrupted basolateral amygdala circuits supports negative valence bias in depressive states

Negative bias is an essential characteristic of depressive episodes leading patients to attribute more negative valence to environmental cues. This negative bias affects all levels of information processing including emotional response, attention and memory, leading to the development and maintenance of depressive symptoms. In this context, pleasant stimuli become less attractive and unpleasant ones more aversive, yet the related neural circuits underlying this bias remain largely unknown. By studying a mice model for depression chronically receiving corticosterone (CORT), we showed a negative bias in valence attribution to olfactory stimuli that responds to antidepressant drug. This result paralleled the alterations in odor value assignment we observed in bipolar depressed patients. Given the crucial role of amygdala in valence coding and its strong link with depression, we hypothesized that basolateral amygdala (BLA) circuits alterations might support negative shift associated with depressive states. Contrary to humans, where limits in spatial resolution of imaging tools impair easy amygdala segmentation, recently unravelled specific BLA circuits implicated in negative and positive valence attribution could be studied in mice. Combining CTB and rabies-based tracing with ex vivo measurements of neuronal activity, we demonstrated that negative valence bias is supported by disrupted activity of specific BLA circuits during depressive states. Chronic CORT administration induced decreased recruitment of BLA-to-NAc neurons preferentially involved in positive valence encoding, while increasing recruitment of BLA-to-CeA neurons preferentially involved in negative valence encoding. Importantly, this dysfunction was dampened by chemogenetic hyperactivation of BLA-to-NAc neurons. Moreover, altered BLA activity correlated with durable presynaptic connectivity changes coming from the paraventricular nucleus of the thalamus, recently demonstrated as orchestrating valence assignment in the amygdala. Together, our findings suggest that specific BLA circuits alterations might support negative bias in depressive states and provide new avenues for translational research to understand the mechanisms underlying depression and treatment efficacy.

Non-contact identification of essential oils with IR sensors and analysis of components with an electronic nose

AbstractIn this study, the odour values of rosemary, mint, black cumin, lavender, and thyme oils were determined by an electronic nose working with an Arduino microprocessor. The components of the plants were compared with the sensor data, and the most sensitive sensors were determined by sorting according to the highest components. The study data indicated that the MQ3 sensor exhibited the highest sensitivity for thyme, black cumin, and lavender oils, which contain 63% carvacrol, 38% thymoquinone, and 36% linalool, respectively. Also, MQ7 was the most sensitive sensor for menthone (68%) in mint oil and eucalyptol (45%) in rosemary oil. In addition, a low-cost and non-contact device that works with an infrared sensor has been developed to detect the identity of the oil added into the vial. The study data showed that low-cost Arduino-based IR and odour sensors can determine the identity and component percentage of oils. The fact that the developed device can detect with 100 percent accuracy even in case of peppermint and rosemary oils, which are very similar in appearance, shows that the study data will be an inspiration for contactless determination of oil quality and type.

Serotonergic input from the dorsal raphe nucleus shapes learning-associated odor responses in the olfactory bulb.

Neural activity in the olfactory bulb (OB) can represent odor information during different brain and behavioral states. For example, the odor responses of mitral/tufted (M/T) cells in the OB change during learning of odor-discrimination tasks and, at the network level, beta power increases and the high gamma (HG) power decreases during odor presentation in such tasks. However, the neural mechanisms underlying these observations remain poorly understood. Here, we investigate whether serotonergic modulation from the dorsal raphe nucleus (DRN) to the OB is involved in shaping activity during the learning process in a go/no-go task in mice. Fiber photometry was used to record the population activity of DRN serotonergic neurons during a go/no-go task. Invivo electrophysiology was used to record neural activity (single units and local field potentials) in the OB during the go/no-go task. Real-time place preference (RTPP) and intracranial light administration in a specific subarea (iClass) tests were used to assess the ability of mice to encoding reward information. Odor-evoked population activity in serotonergic neurons in the DRN was shaped during the learning process in a go/no-go task. In the OB, neural activity from oscillations to single cells showed complex, learning-associated changes and ability to encode information during an odor discrimination task. However, these properties were not observed after ablation of DRN serotonergic neurons. The activity of neural networks and single cells in the OB, and their ability to encode information about odor value, are shaped by serotonergic projections from the DRN.

Development of active hydrogel absorbent pads based on sodium alginate/potassium-doped carbon dots for chilled pork preservation

In this study, potassium-doped carbon dots (K-CDs) were added to sodium alginate (NaAlg) hydrogel to yield high-strength, antibacterial, antioxidant NaAlg hydrogel absorbent pads (NaAlg/K-CDs) to absorb chilled pork exudate during storage. The results revealed that the swelling rates of the NaAlg/K-CDs peaked at 3286.83%, a figure exceeding that of the commercial absorbent pads. Based on the bacterial diversity and richness results, Pseudomonas aeruginosa (P. aeruginosa) was evidently the dominant spoilage organism during chilled pork storage. On storage day 6, the P. aeruginosa population in the NaAlg/K-CDs hydrogel absorbent pad group was 82% of that in the control group. The total volatile basic nitrogen (TVB-N) value of the NaAlg/K-CDs group remained lower than 0.15 mg/g on day 8. The pH, TVB-N, total viable count (TVC), cooking loss, and volatile odour values of the chilled pork in the NaAlg/K-CDs hydrogel absorbent pad group were significantly lower than those in other absorbent pad groups. Moreover, the colour change and shear force values of the chilled pork in the NaAlg/K-CDs hydrogel absorbent pad group were lower than those in the control and wood fiber paper absorbent pad groups. These results indicate that the shelf life of the NaAlg/K-CDs-packaged chilled pork was extended by 2 days compared with that of the control. Therefore, the NaAlg/K-CDs hydrogel absorbent pads potentially inhibited microbial growth and improved the storage quality of chilled pork. This study provides an alternative solution against traditional chilled pork absorbent pads, further promoting the advancement of fresh meat preservation techniques.

Negative valence encoding in the lateral entorhinal cortex during aversive olfactory learning

Olfactory learning is widely regarded as a substrate for animal survival. The exact brain areas involved in olfactory learning and how they function at various stages during learning remain elusive. Here, we investigate the role of the lateral entorhinal cortex (LEC) and the posterior piriform cortex (PPC), two important olfactory areas, in aversive olfactory learning. We find that the LEC is involved in the acquisition of negative odor value during olfactory fear conditioning, whereas the PPC is involved in the memory-retrieval phase. Furthermore, inhibition of LEC CaMKIIα+ neurons affects fear encoding, fear memory recall, and PPC responses to a conditioned odor. These findings provide direct evidence for the involvement of LEC CaMKIIα+ neurons in negative valence encoding.

Dopaminergic neurons dynamically update sensory values during olfactory maneuver

Dopaminergic neurons (DANs) drive associative learning to update the value of sensory cues, but their contribution to the assessment of sensory values outside the context of association remains largely unexplored. Here, we show in Drosophila that DANs in the mushroom body encode the innate value of odors and constantly update the current value by inducing plasticity during olfactory maneuver. Our connectome-based network model linking all the way from the olfactory neurons to DANs reproduces the characteristics of DAN responses, proposing a concrete circuit mechanism for computation. Downstream of DANs, odors alone induce value- and dopamine-dependent changes in the activity of mushroom body output neurons, which store the current value of odors. Consistent with this neural plasticity, specific sets of DANs bidirectionally modulate flies' steering in a virtual olfactory environment. Thus, the DAN circuit known for discrete, associative learning also continuously updates odor values in a nonassociative manner.

The effectiveness of coconut shell charcoal and activated carbon on deodorization of sludge from ice cream industry WWTP

Coconut shell contains several components of biomass including cellulose, lignin, and pentosan, which can be used in the form of charcoal as a bioabsorbent. Sludge waste is a residue formed as a by-product of wastewater treatment at a wastewater treatment plant (WWTP). which emits odors that can disturb local residents. This study aimed to deodorize ice cream slurry waste using coconut shell charcoal and activated carbon as the odor adsorbent. The ratio of each adsorbent and ice cream waste was based on the preliminary experiment, namely 1:1, 1:3, 1:5, 1:6, and 1:7. The measurement parameters for the sludge were odor value, pH, temperature, and water content which were measured daily. Ammonia and sulfide levels were measured using the titration method, while protein levels were determined using a UV-Vis spectrophotometer. Odor reduction in sludge waste mixed with activated carbon as the adsorbent was better than that with coconut shell charcoal; by which the optimum mass ratio was 1:3 with a decrease of 97.13% that was obtained within seven days. The ammonia levels in the sludge waste decreased from 10,276 mg/kg to 308 mg/kg by the use of coconut shell charcoal with a mass ratio of 1:1 and to 252 mg/kg by the use of activated carbon with a mass ratio of 1:1 at the end of the experiment. The sulfide content in the sludge waste decreased from 1.215 mg/L to 0.0483 mg/L in the sample with coconut shell charcoal as an adsorbent with a mass ratio of 1:1 and to 0.0483 mg/L in samples with activated carbon adsorbent ratio of 1:1 at the end of the experiment.

Anosmia/hyposmia differences between severe acute respiratory syndrome coronavirus 2 variants; objective olfactory function evaluation

Objectives: This study aimed to investigate whether the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants cause more or less loss of smell than the wild type variant as a clinical finding that may guide physicians in addition to the increased mortality feature. Patients and Methods: In the prospective study, Connecticut Chemosensory Clinical Research Center (CCCRC) odor testing was performed on patients hospitalized for coronavirus disease 2019 (COVID-19) between May 2021 and December 2021, and variants of SARS-CoV-2 isolated from patients were analyzed. A total of 51 patients (30 males and 21 females; mean age 59.3±14.2 years; range, 29 to 88 years) were included in the study. Age, sex, and COVID-19 vaccine status of the patients were recorded. The patients were asked whether they had new-onset odor or taste complaints and whether they differently perceived smells they knew. Results: The delta variant was detected in 14 patients, the alpha variant was detected in 20 patients, and no variant of concern was detected in 17 patients. Odor disorders were present in 79.4% of all patients (13.73% anosmia, 15.69% severe hyposmia, 13.7% moderate hyposmia, and 37.2% mild hyposmia). There was no statistically significant difference between sex, age, smoking habits, presence of parosmia, degree of smell disorder, and Vicks definition results according to the variants (p>0.05). A statistically significant difference was found between alpha and delta variants in terms of patients' complaints of decreased smell and taste, mean olfactory threshold value, and mean olfactory score variables (p<0.05). There was no difference in terms of age and identification score. The complaints of smell and taste disorders, the mean threshold value of odor, and the mean odor score were found to be significantly lower in the delta variant than in the alpha variant. Conclusion: SARS-CoV-2 variants differ significantly in olfactory dysfunction. Future clinical and laboratory studies may show the diagnostic, clinical, and prognostic significance of olfactory nerve injury.

Emission of volatile sulphur compounds during swine manure composting: Source identification, odour mitigation and assessment

This study aimed to identify the sources of volatile sulphur compounds (VSCs) and evaluate their mitigation by ferric oxide (Fe2O3) during swine manure composting. Four chemicals, including l-cysteine, l-methionine, sodium sulphite, and sodium sulphate, were further added to simulate organic and inorganic sulphur-containing substances in swine manure to track VSC sources during composting. Results show that sulphur simulants induced the emission of six common VSCs, including methyl sulphide (Me2S), dimethyl sulphide (Me2SS), carbonyl sulphide (COS), carbon disulphide (CS2), methyl mercaptan (MeSH), and ethyl mercaptan (EtSH), during swine manure composting. Of them, COS, CS2, MeSH and Me2SS were predominantly contributed by the biodegradation of methionine and cysteine, while Me2S and EtSH were dominated by the reduction of sulphite and sulphate. Further Fe2O3 addition at 1.5 % of total wet weight of composting materials immobilized elemental sulphur and inhibited sulphate reduction to reduce the emission of VSCs by 46.7–80.9 %. Furthermore, odour assessment indicated that adding Fe2O3 into composting piles significantly reduced the odour intensity level to below 4, the odour value of VSCs by 47.1–81.3 %, and thus the non-carcinogenic risk by 68.4 %.

Comparison between macroscopic identification and DNA barcoding identification of Amomi Fructus

This study aims to explore the consistency between macroscopic identification and DNA barcoding identification of Amomi Fructus. With the DNA barcoding identification results, we evaluated the reliability of identifying Amomi Fructus quality by combining macroscopic traits with main volatile chemical components. Thirteen batches of Amomi Fructus samples were collected for identification. Firstly, the morphological and sensory characteristics of each sample were observed and recorded according to the standard in Chinese Pharmacopoeia(2020 edition). The 100-fruit weight, longitudinal diameter, transverse diameter, and longitudinal diameter-to-transverse diameter ratio were measured, which correspond to large, solid, and full kernel representing good quality in the sensory evaluation. The odor value detected by electronic nose and major volatile components(borneol, camphor, limonene, and borneol acetate) correspond to the sensory evaluation of strong odor representing good quality. Secondly, DNA barcoding was employed to identify the 13 batches of samples. Finally, clustering analysis was performed for the main volatile components and macroscopic traits, and the identification results were compared with those of DNA barcoding. Except two batches of samples(No.6 and No.10), the macroscopic identification showed the results consistent with those of DNA barcoding, with an identification rate of 84.62%. The clustering results of the content of four volatile chemical components and macroscopic traits were also consistent with the DNA barcoding identification results. DNA barcoding can verify the results of macroscopic identification and provide a scientific basis for the inheritance and development of macroscopic identification. Moreover, the combination of macroscopic traits and chemical components demonstrates higher accuracy in the quality evaluation of Chinese medicinal materials.

The effect of different solvents on the production of rose concrete and rose absolute, experimental study and thermodynamic aspects using the UNIFAC model

Rosa damascena Mill. is one of the rosa species that is broadly used for commercial products such as rose concrete and rose absolute. First, the effect of two organic solvents of hexane and ethyl acetate and three alcohols of methanol, ethanol, and 2-propanol were studied on the yield and quality of the rose concrete and rose absolute from air-dried petals of Rosa damascena Mill. Then, a predictive thermodynamic model based on the UNIFAC activity coefficient was employed to predict the composition of rose absolute obtained from the rose concrete. The extraction of rose concrete from dried rose petals was performed at 30 °C by hexane or ethyl acetate, and then the produced rose concrete was combined with an alcohol and the mixture was placed at −18 °C for 48 h to produce rose absolute. Based on the results, the maximum yield of rose absolute was achieved if the extractions were performed with ethyl acetate to extract rose concrete, and ethanol to extract rose absolute. The extracts were analyzed using a GC-MS method to determine the effect of the solvents on the quality of the rose absolute. The most critical constituents detected in the extracts were high-value fragrant components of phenyl ethyl alcohol, citronellol, geraniol, nerol, and farnesol. The results showed that using the pair of hexane and methanol led to achieving a rose absolute with the highest odor value (16,038) but a low extraction yield. Using ethyl acetate and ethanol, the maximum yield of rose absolute was achieved. Finally, the thermodynamic model showed a good agreement in predicting the rose absolute production from the rose concrete with the alcohols.

Deodorizing effects of rosemary extract on silver carp (Hypophthalmichthys molitrix) and determination of its deodorizing components.

Fishy odor in fish products severely influences both eating quality and commercial acceptability, and natural plant extracts, particularly spices, have recently become popular for the removal of fishy odor. This study aimed to explore the potential of rosemary extract for the deodorization of silver carp (Hypophthalmichthys molitrix), as well as to identify the deodorizing components in rosemary extract. Results showed that all of the spice extracts used in this study (ginger, garlic, angelica dahurica, fennel, rosemary, nutmeg, white cardamom, cinnamon, star anise, and bay leaf) significantly reduced the fishy odor value of silver carp, among which rosemary extract was most effective, decreasing the fishy odor value by about 58%. Gas chromatography-mass spectrometry analysis and sensory evaluation showed that the fishy odor value and concentrations of the fishy odor-active compounds were significantly reduced by the application of rosemary extract. However, the lower the total phenolic content of rosemary extract, the poorer the deodorizing effects against silver carp, suggesting that the deodorizing effect was primarily driven by polyphenols. Fourteen phenolic compounds were measured in rosemary extract, and three individual phenolic compounds (rosmarinic acid [RA], carnosic acid [CA], and carnosol [CS]) were chosen for deodorizing experiment. Sensory detection results and changes of contents of volatile showed that these three phenolic compounds are effective at removing the fishy odor. These results suggest that polyphenols are the main deodorizing components, and RA, CA, and CS are the main deodorizing active compounds in rosemary extract. PRACTICAL APPLICATION: The results of this study may provide a new way to determine the deodorizing components of spice extracts. Moreover, it can provide guidance for further research in investigating the deodorizing mechanism of sipce extracts.

The Complexity of Olfactory Art The Use of Scent as Concept and Context in the Work of Art

The sense of smell is a powerful sense that offers many possibilities. To speak of olfactory art, there must be the intention to use odour or olfaction as both context and concept of the work of art. For this, we speak about the terms Olfactory Context and Olfactory Concept. The Olfactory Context can be divided into the Intrinsic and Intentional Odour Values. The intrinsic odour value brings with it their significance, while the intentional odour value gives an extra meaning to a smell. In addition, the Olfactory Perception is part of the Olfactory Concept of the artwork. To perceive this, the smell must be transferred to the spectator. The way in which an odour is transferred in a work largely determines how the smell is interpreted in relation to the work. The odour transfer and odour situation determine how an odour gets to the viewer. We call these methods of odour transfer Olfactory Transfers and divide them into five categories: Flowers, Smell Devices, Scent Spaces, Time and Translations. In most cases, Olfactory Transfers are used in crossovers. Together with the various possibilities of using the Olfactory Context, they also demonstrate the Complexity of Olfactory Art. The 1st Olfactory Art Manifest explains the differences in olfactory art, while the 2nd Olfactory Art Manifest demonstrates the Complexity of Olfactory Art.

Circuits for integrating learned and innate valences in the insect brain.

Animal behavior is shaped both by evolution and by individual experience. Parallel brain pathways encode innate and learned valences of cues, but the way in which they are integrated during action-selection is not well understood. We used electron microscopy to comprehensively map with synaptic resolution all neurons downstream of all mushroom body (MB) output neurons (encoding learned valences) and characterized their patterns of interaction with lateral horn (LH) neurons (encoding innate valences) in Drosophila larva. The connectome revealed multiple convergence neuron types that receive convergent MB and LH inputs. A subset of these receives excitatory input from positive-valence MB and LH pathways and inhibitory input from negative-valence MB pathways. We confirmed functional connectivity from LH and MB pathways and behavioral roles of two of these neurons. These neurons encode integrated odor value and bidirectionally regulate turning. Based on this, we speculate that learning could potentially skew the balance of excitation and inhibition onto these neurons and thereby modulate turning. Together, our study provides insights into the circuits that integrate learned and innate valences to modify behavior.

Additivity between Key Odorants in Pig House Air

The verification of odor abatement technologies for livestock production based on chemical odorants requires a method for conversion into an odor value that reflects the significance of the individual odorants. The aim of the present study was to compare the SOAV method (Sum of Odor Activity Values) with the odor detection threshold measured by olfactometry and to investigate the assumption of additivity. Synthetic pig house air with odorants at realistic concentration levels was used in the study (hydrogen sulfide, methanethiol, trimethylamine, butanoic acid, and 4-methylphenol). An olfactometer with only PTFE in contact with sample air was used to estimate odor threshold values (OTVs) and the odor detection threshold for samples with two to five odorants. The results show a good correlation (R2 = 0.88) between SOAV estimated based on the OTVs for panelists in the present study and values found in the literature. For the majority of the samples, the ratio between the odor detection threshold and SOAV was not significantly different from one, which indicates that the OAV for individual odorants in a mixture can be considered additive. In conclusion, the assumption of additivity between odorants measured in pig house air seems reasonable, but the strength of the method is determined by the OTV data used.

A Mechanistic Model for Reward Prediction and Extinction Learning in the Fruit Fly.

Extinction learning, the ability to update previously learned information by integrating novel contradictory information, is of high clinical relevance for therapeutic approaches to the modulation of maladaptive memories. Insect models have been instrumental in uncovering fundamental processes of memory formation and memory update. Recent experimental results in Drosophila melanogaster suggest that, after the behavioral extinction of a memory, two parallel but opposing memory traces coexist, residing at different sites within the mushroom body (MB). Here, we propose a minimalistic circuit model of the Drosophila MB that supports classical appetitive and aversive conditioning and memory extinction. The model is tailored to the existing anatomic data and involves two circuit motives of central functional importance. It employs plastic synaptic connections between Kenyon cells (KCs) and MB output neurons (MBONs) in separate and mutually inhibiting appetitive and aversive learning pathways. Recurrent modulation of plasticity through projections from MBONs to reinforcement-mediating dopaminergic neurons (DAN) implements a simple reward prediction mechanism. A distinct set of four MBONs encodes odor valence and predicts behavioral model output. Subjecting our model to learning and extinction protocols reproduced experimental results from recent behavioral and imaging studies. Simulating the experimental blocking of synaptic output of individual neurons or neuron groups in the model circuit confirmed experimental results and allowed formulation of testable predictions. In the temporal domain, our model achieves rapid learning with a step-like increase in the encoded odor value after a single pairing of the conditioned stimulus (CS) with a reward or punishment, facilitating single-trial learning.

Predictive olfactory learning in Drosophila

Olfactory learning and conditioning in the fruit fly is typically modelled by correlation-based associative synaptic plasticity. It was shown that the conditioning of an odor-evoked response by a shock depends on the connections from Kenyon cells (KC) to mushroom body output neurons (MBONs). Although on the behavioral level conditioning is recognized to be predictive, it remains unclear how MBONs form predictions of aversive or appetitive values (valences) of odors on the circuit level. We present behavioral experiments that are not well explained by associative plasticity between conditioned and unconditioned stimuli, and we suggest two alternative models for how predictions can be formed. In error-driven predictive plasticity, dopaminergic neurons (DANs) represent the error between the predictive odor value and the shock strength. In target-driven predictive plasticity, the DANs represent the target for the predictive MBON activity. Predictive plasticity in KC-to-MBON synapses can also explain trace-conditioning, the valence-dependent sign switch in plasticity, and the observed novelty-familiarity representation. The model offers a framework to dissect MBON circuits and interpret DAN activity during olfactory learning.

Flexible categorization in the mouse olfactory bulb

The ability to group sensory stimuli into categories is crucial for efficient interaction with a rich and ever-changing environment. In olfaction, basic features of categorical representation of odors were observed as early as in the olfactory bulb (OB). Categorical representation was described in mitral cells (MCs) as sudden transitions in responses to odors that were morphed along a continuum. However, it remains unclear to what extent such response dynamics actually reflect perceptual categories and decisions therein. Here, we tested the role of learning on category formation in the mouse OB, using invivo two-photon calcium imaging and behavior. We imaged MC responses in naive mice and in awake behaving mice as they learned two tasks with different classification logic. In one task, a one-decision-boundary task, animals learned to classify odor mixtures based on the dominant compound in the mixtures. As expected, categorical representation of odors, which was evident already in naive animals, further increased following learning. In a second task, a multi-decision-boundary task, animals learned to classify odors independent of their chemical similarity. Here, odor discrimination was based on the meaning ascribed to them (either rewarding or not). Following the multi-decision-boundary task, odor representations by MCs reorganized according to the odor value in the new category. This functional reorganization was also reflected as a shift from predominantly excitatory odor responses to predominantly inhibitory odor responses. Our data show that odor representations by MCs are flexible, are shaped by task demands, and carry category-related information.

Essential oils, their quality assurance, management and stakes of CSIR-CIMAP (India): Past and future perspectives

The essential oil’s quality in the 21st Century might become the mainstay of ‘green consumerism’ creating a niche market for food, flavour, fragrance, pharmaceuticals, and lately aromatherapy. The oil obtained from a specific aromatic plant entails complex quality characteristics, like sensory satisfaction (odour value), physical conditions, chemical profile/composition, and allied features. This is imperative to make natural essential oils more remunerative with low cost of cultivation, more attractive in national and international markets with superior quality and competitively cheaper prices, and more conducive for internal consumption with abundant production. A large number of both exogenous and endogenous factors, such as seeds, planting materials, edapho-climatic conditions, and herbi-cultural factors, like, pre-and post-harvest management, down-stream processing, etc. tend to influence the quality of oil, deliberate adulterations of oil not with standing. Moreover, most of the time during essential oil production, human assault on ecology or environment defeats the cause of sustainable use of natural and or domestic plant resources. India is a vibrant producer and supplier of natural essential oils to the world market. It has to play even a more dominant role in the production and processing of essential oils beyond 2000 AD to capitalize on the advantages of the current economic liberalization of globalization under the new regime of the World Trade Organization (WTO). Therefore, quality assurance, i.e., compliance with a set of specification or standards of commercial essential oils based on the philosophy of the Total Quality Management (TQM) involving customer orientation, process control, and constant improvement of quality coupled with ISO 9000 and ISO 14000 certifications must be achieved by taking due care at different vital stages of essential oil production and processing. These stages as well as quality management of essential oils about (i) realization of in situ quality of the plant material chosen, (ii) enrichment or value addition of the oils, (iii) rectification of oils produced, and (iv) warding off from adulteration or inadvertent mixing, have been critically described in this presentation. Suggestions have also been made to make the essential oil eco-friendly products. However, a couple of vital questions remain to be answered by the essential oil industry and public agencies alike for achieving the ultimate goals of TQM of essential oils in India.