Effect of industrial wastewater treatment system upgrade on the composition of emitted odorants and volatile organic compounds from a cheese production facility

This study investigates the rarely studied volatile organic compound emissions from a cheese production facility and the impact of its wastewater treatment system upgrade on the composition of emitted odorants. Wastewater grab samples were collected from six separate wastewater channels before (2019) and after (2021) the system upgrade and analyzed for volatile organic compounds, pH, total dissolved solids, and electrical conductivity. Results showed that the channel from hard cheese production in 2021 had the highest number of volatile organic compounds (35), followed by the fresh cheese production channel (22). Following the industrial wastewater treatment system upgrade, a mineral oil contamination occurred; however, the number of odorants with nasal impact frequency (NIF) ≥ 0.5 in the effluent decreased from 11 to 5. 2-Propenoic acid butyl ester (NIF 0.75) stood out as the most prominent compound, described as fruity, waxy, or green. After the industrial wastewater treatment system upgrades, we observed a decrease in the number of odorants. However other measures must be taken to ensure proper wastewater processing. PRACTITIONER POINTS: More than 60 VOCs were identified in 6 channels from the cheese production facility.15 odorants in cheese production wastewater were detected by SPME-GC-MS/O. The most potent odorants before and after the system upgrade were 1-octen-3-ol and 2-propenoic acid butyl ester, respectively. The upgrades of the industrial wastewater treatment system had a positive impact on reducing the number of odorants and their odor intensity.

Development and Validation of a New Method for Detecting Acetic Bacteria in Wine

In winemaking, excessive production of acetic acid by acetic acid bacteria poses a major challenge, leading to rejection of wine by consumers. The aim of this study was to devise an economically viable and easy-to-use liquid culture medium for the preventive detection of microorganisms capable of generating acetic acid in wine. The modified medium incorporated specific nutrients that favored the growth of acetic acid bacteria and increased selectivity. Under varying conditions and with different types of wine, this medium was tested together with inoculated samples, comparing the occurrence of acetic acid and olfaction. The result was a new liquid medium based on olfactometry, designed to facilitate its use in wineries, even by untrained personnel and without the need for complex laboratory equipment. Validation was carried out on a variety of wines, determining the onset of the presence of acetic acid in the medium. This innovative culture medium provides a means to estimate the concentration of micro-organisms capable of producing acetic acid in wine. Its application in wineries facilitates proactive decision making, avoiding undesirable increases in acetic acid concentration.

Chemical and Olfactory Analysis of the Volatile Fraction of Ocimum gratissimum Concrete from Madagascar

The chemical composition of the volatile fraction of Ocimum gratissimum concrete (romba) from Madagascar has been determined for the first time by GC/MS and GC-FID. A methyl cinnamate chemotype has been determined for this material, along with a set of compounds typical in essential oils and extracts from plants of the Ocimum genus. Variability was mostly observed on terpenes and terpenoids components. GC-O-MS was also used for a sensory evaluation of this material performed by a master perfumer. The chemical composition of this O. gratissimum extract was then compared with literature data to assess subtle differences between chemotypes of the same species and other species of the same genus within natural variability. A mapping illustrates the occurrence of the cinnamate chemotype in Eastern Africa, India and now Madagascar, while other origins generally present eugenol, thymol, camphor, or linalool chemotypes.

Indoor Air Quality-An Overview of Methods for Measuring Odor Detection Thresholds of Single Substances

Odor evaluation is an important topic in the field of indoor air quality. Odor detection threshold (ODT) values are used to derive limit values like odor guide values or odor activity value. However, ODT values for the same substance available in compilations or published before 2003 rarely have an accuracy of less than three orders of magnitude. Stimulus preparation, including analytical verification, stimulus presentation, as well as selection and training of test subjects have been identified as major sources of variability. ODT values obtained by validated standardized methods are now considered objective, reliable, and reproducible. They exhibit a variability of one or two orders of magnitude and are lower than traditionally assumed and reported. This review presents the essential criteria for a well-performed ODT determination. It is intended to assist health and safety professionals in assessing whether the methodological approach of a study was appropriate for determining a valid and reliable ODT value.

Reconsidering the olfactory and brain structures in Kallmann's syndrome: New findings in the analysis of volumetry

OBJECTIVE

Kallmann's syndrome (KS) is characterized by hypogonadotropic hypogonadism and olfactory disorders. The complementary exams for evaluating of patients with hypogonadotrophic hypogonadism are important for the diagnosis and management of these patients.

PATIENTS

We performed a well-established olfactory Sniffin' Stick test (SST) on 17 adult patients with KS and brain magnetic resonance imaging (MRI) to evaluate olfactory structures and further analysis by Freesurfer, a software for segmentation and volumetric evaluation of brain structures. We compared the Freesurfer results with 34 healthy patients matched for age and sex and performed correlations between the data studied.

RESULTS

More than half of the patients with KS reported preserved smell but had olfactory disorders in the SST. In the MRI, 16 patients showed changes in the olfactory groove, the olfactory bulb-tract complex was altered in all of them and 52% had symmetrical structural changes. Interestingly, the pituitary gland was normal in only 29%. Regarding correlations, symmetrical changes in the olfactory structures were related to anosmia in 100%, while asymmetric changes induced anosmia in only 50% (p = .0294). In Freesurfer's assessment, patients with KS, compared to controls, had lower brainstem volume. In those with aplastic anterior olfactory sulcus, the brainstem volume was lower than in hypoplasia (p = .0333).

CONCLUSIONS

Olfactory assessment and MRI proved to be important auxiliary tools for the diagnosis and management of patients with KS. New studies are needed to confirm the decrease in brainstem volume found by the Freesurfer software in patients with KS. Further studies are needed to confirm the decrease in brainstem volume found by the Freesurfer software in patients with KS.

Estimating the relationship between liquid- and vapor-phase odorant concentrations using a photoionization detector (PID)-based approach

Olfactory studies frequently utilize odor stimuli consisting of volatiles created from liquid dilutions of various chemicals. A problem arises if the researcher relies on these liquid dilutions to extrapolate vapor concentrations based on ideal gas behavior. For most chemicals, the relationship between liquid and vapor concentration deviates from these laws of proportionality due to interactions between the chemical and the solvent. Here, we describe a method to estimate vapor-phase concentrations of diluted odorants using a photoionization detector. To demonstrate the utility of this method, we assessed the relationship between liquid-/vapor-phase concentrations for 14 odorants (7 alcohols, 1 ester, and 6 aldehydes) in 5 different solvents (water, mineral oil, diethyl phthalate, dipropylene glycol, and propylene glycol). An analysis of 7 additional esters is also included to assess how carbon chain length and functional group, interacts with these solvents (for a total of 105 odorant/solvent pairs). Our resulting equilibrium equations successfully corrected for behavioral sensitivity differences observed in mice tested with the same odorant in different solvents and were overall similar to published measurements using a gas chromatography-based approach. In summary, this method should allow researchers to determine the vapor-phase concentration of diluted odorants and will hopefully assist in more accurate comparisons of odorant concentrations across olfactory studies.

Bibliometric Review on the Volatile Organic Compounds in Meat

Meat flavor is an important aspect of meat quality that also influences consumer demand, and is therefore very important for the meat industry. Volatile organic compounds (VOCs) contribute in large part to the flavor of meat, and while increasing numbers of articles are published on this topic, reviews of these articles are very scarce. Therefore, our aim was to perform a bibliometric analysis of the scientific publications on VOCs in meat over the period 2000-2020. We selected 611 scientific sources from the Scopus database related to VOCs in meat (seafood excluded). The bibliometric information retrieved included journals, authors, countries, institutions, keywords, and citations. From this analysis, we drew up a list of the most important journals, authors, countries, and institutions, and the trends in VOC research on meat. We conducted a social network analysis (SNA) to identify the collaborations among the many authors and countries, and a keyword analysis to generate a network map of the authors' keywords. We also determined which meat species were most frequently chosen as research subjects, traced the evolution of the various methods/instruments used, and explored the research tendencies. Finally, we point out the need for further research in defining meat quality, improving meat flavor, identifying adulterants, and certifying the authenticity of meat.

Electronic Noses and Their Applications for Sensory and Analytical Measurements in the Waste Management Plants-A Review

Waste management plants are one of the most important sources of odorants that may cause odor nuisance. The monitoring of processes involved in the waste treatment and disposal as well as the assessment of odor impact in the vicinity of this type of facilities require two different but complementary approaches: analytical and sensory. The purpose of this work is to present these two approaches. Among sensory techniques dynamic and field olfactometry are considered, whereas analytical methodologies are represented by gas chromatography–mass spectrometry (GC-MS), single gas sensors and electronic noses (EN). The latter are the core of this paper and are discussed in details. Since the design of multi-sensor arrays and the development of machine learning algorithms are the most challenging parts of the EN construction a special attention is given to the recent advancements in the sensitive layers development and current challenges in data processing. The review takes also into account relatively new EN systems based on mass spectrometry and flash gas chromatography technologies. Numerous examples of applications of the EN devices to the sensory and analytical measurements in the waste management plants are given in order to summarize efforts of scientists on development of these instruments for constant monitoring of chosen waste treatment processes (composting, anaerobic digestion, biofiltration) and assessment of odor nuisance associated with these facilities.

Influence of protein extraction and texturization on odor-active compounds of pea proteins

BACKGROUND

The use of plant proteins as food ingredients might be limited due to the presence of foreign or 'off' flavors, which may evolve during extraction and subsequent processing. In this study, the influence of dry (TVP) and wet (WTP) texturization on characteristic volatile compounds of two different pea protein isolates was assessed using gas chromatography-mass spectrometry-olfactometry (GC-MS-O) after direct immersion stir bar sorptive extraction (DI-SBSE).

RESULTS

Twenty-four odor-active compounds were found, with a prevalence of carbonyls from fat oxidation. Nine of these compounds which are also known as major (off-) flavor contributors in peas were distinctively impacted in all texturates: hexanal, nonanal, 2-undecanone, (E)-2-octenal, (E, Z)-3,5-octadiene-2-one, (E, E)-2,4-decadienal, 2-pentyl-furan, 2-pentyl-pyridine, and γ-nonalactone. For example, hexanal, a characteristic green odorant, was reduced by up to sixfold by wet texturization, from 3.29 ± 1.05% (Pea Protein I) to 0.52 ± 0.02% (Pea WTP I). Furthermore, (E,Z)-3,5-Octadiene-2-one and (E,E)-2,4-decadienal were decreased by 1.5- and 1.8-fold when Pea Protein I and Pea TVP I were compared.

CONCLUSION

An overall reduction in fat oxidation products and of green and fatty odor-active compounds was observed. The results represent a first insight into the process-related modulation of pea protein (off-) flavors to broaden the applicability of pea proteins as food ingredients.

Identification of Olfactory Nuisance of Floor Products Containing Bitumens with the TD-GC-MS/O Method

The adopted TD–GC–MS/O method helps determine the correlation between the odour signals and compounds separated on the chromatographic column, from the analysed gas mixture. It is possible to compare the retention times at which the odour signals were identified with the retention time of eluting compounds, when the test system and matrix are known. The presented study describes the details of representative samples obtained from (1) indoor air samples from a room where floor materials containing bitumen are present, (2) wooden floor staves placed in an emission chamber, and (3) fragments (chips) of the materials mentioned above, placed in glass tubes, exposed to an elevated desorption temperature. The results, presented in the paper, describe the identified odours and their intensity and assign chemical compounds to each odour, indicating their likely source of origin. The results presented in the manuscript are intended to show what methodology can be adopted to obtain intense odours from the tested samples, without losing the sensitivity derived from GC–MS. The manuscript presents representative results—case studies. The results for various types of samples were not very reproducible, related to the complex matrix of bituminous products. The enormity of compounds present in tar adhesives makes it possible to indicate only the groups of compounds that emit from these systems. They include, primarily, aliphatic, aromatic and heteroaromatic hydrocarbons, particularly Naphthalene and Phenol derivatives.

Odor and Constituent Odorants of HDPE-Lignin Blends of Different Lignin Origin

The still-rising global demand for plastics warrants the substitution of non-renewable mineral oil-based resources with natural products as a decisive step towards sustainability. Lignin is one of the most abundant natural polymers and represents an ideal but hitherto highly underutilized raw material to replace petroleum-based resources. In particular, the use of lignin composites, especially polyolefin-lignin blends, is currently on the rise. In addition to specific mechanical property requirements, a challenge of implementing these alternative polymers is their heavy odor load. This is especially relevant for lignin, which exhibits an intrinsic odor that limits its use as an ingredient in blends intended for high quality applications. The present study addressed this issue by undertaking a systematic evaluation of the odor properties and constituent odorants of commercially available lignins and related high-density polyethylene (HDPE) blends. The potent odors of the investigated samples could be attributed to the presence of 71 individual odorous constituents that originated primarily from the structurally complex lignin. The majority of them was assignable to six main substance classes: carboxylic acids, aldehydes, phenols, furan compounds, alkylated 2-cyclopenten-1-ones, and sulfur compounds. The odors were strongly related to both the lignin raw materials and the different processes of their extraction, while the production of the blends had a lower but also significant influence. Especially the investigated soda lignin with hay- and honey-like odors was highly different in its odorant composition compared to lignins resulting from the sulfurous kraft process predominantly characterized by smoky and burnt odors. These observations highlight the importance of sufficient purification of the lignin raw material and the need for odor abatement procedures during the compounding process. The molecular elucidation of the odorants causing the strong odor represents an important procedure to develop odor reduction strategies.

A non-randomized comparative study of olfactory and gustatory functions in children who recovered from COVID-19 (1-year follow-up)

The experimental group included 68 children over 6 years of age who had recovered from COVID-19. The control group included 22 children over 6 years of age who have never had COVID-19. Research methods included neurological examination, verification of cognitive status, examination by an otolaryngologist, and smell and taste assessment. The examination was performed 6-8 weeks after COVID-19 recovery and after 1 year in some patients. Children who recovered from COVID-19 had a reduction in their ability to smell compared to children who had never had COVID-19. The olfactory thresholds and taste identification scores after recovery from COVID-19 were identical, whether the parents had reported anosmia in their children during COVID-19 or not, and irrespective of hyperthermia level and the presence or absence of headache and hyperhidrosis during COVID-19. Analysis of correlation with neuropsychiatric symptoms showed no differences in the olfactory thresholds in children irrespective of the presence of neuropsychiatric symptoms (tics, tremors, enuresis, compulsive movements, seizures, speech disorders, attention deficit, and easy fatigability) both in general, and in particular among subjects performing or not any compulsive movements, and experiencing or not a combination of easy fatigability and daytime sleepiness. Evidence suggests that in children and adolescents, partial hyposmia is associated with depressive symptoms, varying in severity from low to high, but symptoms of depression were not caused by COVID-19 infection itself. Analysis in subgroups with different degrees of state and trait anxiety did not reveal any significant differences in the olfactory threshold. A re-examination of 21 children was performed after 1 year. An objective olfactometric examination showed that the sensitivity to odorants increased significantly. In 1 year, we compared the thresholds of smell in children who had COVID-19 and those who did not have this disease: olfactory sensitivity after COVID-19 in children is restored to normal values. Schulte correction test showed that none of 14 children with asthenic manifestations in the form of fluctuations or exhaustion when performing the test immediately after COVID-19 had these manifestations after 1 year. Thus, asthenization of cognitive activity was recorded within the next 1.5 months after suffering from COVID-19 but was absent after 1 year.

Mapping odorant sensitivities reveals a sparse but structured representation of olfactory chemical space by sensory input to the mouse olfactory bulb

In olfactory systems, convergence of sensory neurons onto glomeruli generates a map of odorant receptor identity. How glomerular maps relate to sensory space remains unclear. We sought to better characterize this relationship in the mouse olfactory system by defining glomeruli in terms of the odorants to which they are most sensitive. Using high-throughput odorant delivery and ultrasensitive imaging of sensory inputs, we imaged responses to 185 odorants presented at concentrations determined to activate only one or a few glomeruli across the dorsal olfactory bulb. The resulting datasets defined the tuning properties of glomeruli - and, by inference, their cognate odorant receptors - in a low-concentration regime, and yielded consensus maps of glomerular sensitivity across a wide range of chemical space. Glomeruli were extremely narrowly tuned, with ~25% responding to only one odorant, and extremely sensitive, responding to their effective odorants at sub-picomolar to nanomolar concentrations. Such narrow tuning in this concentration regime allowed for reliable functional identification of many glomeruli based on a single diagnostic odorant. At the same time, the response spectra of glomeruli responding to multiple odorants was best predicted by straightforward odorant structural features, and glomeruli sensitive to distinct odorants with common structural features were spatially clustered. These results define an underlying structure to the primary representation of sensory space by the mouse olfactory system.

In-Mouth Volatile Production from Brassica Vegetables (Cauliflower) and Associations with Liking in an Adult/Child Cohort

Interactions between Brassica vegetables and human saliva can affect in-mouth odor development, which in turn may be linked to individual perception and liking. S-Methyl-l-cysteine sulfoxide is a unique substrate present in Brassicas that produces odor-active sulfur volatiles due to the activity of enzymes present in plant tissue and due to bacteria, which may be present to varying extents in an individual's oral microbiome. Proton transfer reaction mass spectrometry was applied to measure individual differences in sulfur volatile production in real time when fresh human saliva was incubated ex vivo with raw cauliflower for a cohort of child-adult pairs. Large differences in the rate of sulfur volatile production were measured between individuals, but not between age groups. Significant positive relationships were found for volatile production between the adult-child pairs, suggesting a degree of commonality in saliva composition and oral microbiome activity. Furthermore, significant negative relationships were measured between the amount of in-mouth sulfur volatile production and liking for raw cauliflower in children.

Mating, but Not Male Accessory Gland Products, Changes Female Response to Olfactory Cues in Anastrepha Fruit Flies

Copulation and/or ejaculate components can alter female physiological state and female post-mating behavior. The objective of the present study was to determine if copulation and male reproductive accessory gland products (MAGs) modify the behavior of female Anastrepha ludens (Loew) and Anastrepha obliqua (Macquart; Diptera: Tephritidae) in response to two stimuli: male-emitted pheromone and oviposition host volatiles. Olfactometry studies revealed that mated females of both A. ludens and A. obliqua have a stronger response for host volatiles compared to unmated females, which have a stronger response for male pheromone. We also examined olfactory responses of females mated to testectomized males who could transfer MAGs but not sperm. In both species, MAGs alone did not cause the change in the olfactory response observed after copulation, unlike what has been found in Ceratitis capitata (Wiedemann). Females mated to testectomized males responded equally to the male sex pheromone or to host volatiles, thus suggesting that the whole ejaculate is needed to elicit the complete behavioral switch in olfactory response. The function of MAGs is still unknown in these two pests of economic importance. The response for host volatiles by mated females has implications for the development of baits and traps that should preferably attract and target this population.

Application of Chemical Sensors and Olfactometry Method in Ecological Audits of Degraded Areas

Mineral excavation is a common process throughout the world. The open pits remaining after the closure of a mine require well-considered and meticulous reclamation activities aimed at restoring the environmental properties of a given area. The inspections carried out in Poland indicate numerous irregularities in implementing the reclamation process. The research in this study was conducted in six measurement series and includes both chemical and olfactometry determinations by devices: multisensor portable gas detector and field olfactometer. Statistical analysis of the results obtained show high concentrations in ambient air of both chemical compounds (NH₃, VOCs, H₂S, CH₃SH) and odour, excluding the possibility of occurrence in the pit of only waste types contained in the administrative decision on reclamation. In addition to the unpleasant odour, the listed compounds can have dangerous effects on the health and life of living organisms. This paper presents a suitable method of control and detection of irregularities in the conducted processes. The main advantage is the relatively low cost of purchasing sensors and field olfactometers compared to other devices, and the possibility to test the polluted air in situ, without the risk of chemical processes occurring during transport of gas samples to the laboratory.

Application of Olfactometry to Assess the Anti-Odor Properties of Filtering Facepiece Respirators Containing Activated Carbon Nonwovens

Filtering facepiece respirators (FFR) with anti-odor properties are used to reduce odor nuisance occurring both in everyday life and at workplaces. Unfortunately, there are no standardized methods to measure the efficiency of odor reduction of such personal protective devices. This paper aims to determine whether olfactometric-based methods, commonly used in environmental studies, can be employed for this purpose. The proposed procedure is based on the detection of n-butanol by study participants, and it consists of three subsequent stages: (i) defining the individual levels of odor sensitivity of each study participant; (ii) determining THE odor detection level while using FFRs with varying anti-odor properties; and (iii) completing a questionnaire concerning the subjective perceptions of study participants. As a measure of odor reduction efficiency, a coefficient W, defined as a quotient of the degree of odor reduction by the FFR, and the individual odor sensitivity of the subject, was proposed. The experimental results showed the ability of our measure to differentiate the effectiveness of odor reduction of tested FFRs. This indicates that it can be potentially employed as the assessment tool to confirm the effectiveness of such respiratory protective devices as a control measure mitigating the adverse effects of malodors on workers’ health, cognition, and behavior.

Behavioral and Antennal Responses of Tribolium confusum to Varronia globosa Essential Oil and Its Main Constituents: Perspective for Their Use as Repellent

Essential oils of aromatic plants represent an alternative to classical pest control with synthetic chemicals. They are especially promising for the alternative control of stored product pest insects. Here, we tested behavioral and electrophysiological responses of the stored product pest Tribolium confusum, to the essential oil of a Brazilian indigenous plant, Varronia globosa, collected in the Caatinga ecosystem. We analyzed the essential oil by GC-MS, tested the effects of the entire oil and its major components on the behavior of individual beetles in a four-way olfactometer, and investigated responses to these stimuli in electroantennogram recordings (EAG). We could identify 25 constituents in the essential oil of V. globosa, with anethole, caryophyllene and spathulenole as main components. The oil and its main component anethole had repellent effects already at low doses, whereas caryophyllene had only a repellent effect at a high dose. In addition, the essential oil abolished the attractive effect of the T. confusum aggregation pheromone. EAG recordings revealed dose-dependent responses to the individual components and increasing responses to the blend and even more to the entire oil. Our study reveals the potential of anethole and the essential oil of V. globosa in the management of stored product pests.

Sensory and Olfactometry Chemometrics as Valuable Tools for Assessing Hops' Aroma Impact on Dry-Hopped Beers: A Study with Wild Portuguese Genotypes

Sensory, olfactometry (using the sums of odour intensities for each class of compounds) and chemometric analyses were used to evaluate Portuguese wild hops’ sensory characteristics and the aroma that those hops impart to dry-hopped beer. CATA analysis and agglomerative hierarchical clustering was applied for the sensory characterization of 15 wild hops of Portuguese genotypes, clustering them in two groups: one more sulphurous, floral, and fruity, and another more earthy, resinous, floral, and non-citrus fruits. Two hops representative of each group were selected for the production of four dry-hopped beers using the same base beer style (Munich Helles). Beers were analysed by quantitative descriptive analyses and quantification of hop-derived key volatile compounds. Multivariate statistical treatment of the data was performed. Results indicate significant differences (p < 0.05) in fruity, resinous, earthy, floral, and sulphurous attributes of hops, but the dry-hopped beers only have a significant increase (p < 0.05) in fruity and spicy notes when compared with non-dry-hopped Munich-style Helles beer. Hop olfactometry explained the sensory perception that the 11 hops not used for brewing (employed as supplementary observations) are placed into the space of the odour-active compounds profile of the four hops selected for brewing. These 11 hop samples have more spiciness than fruitiness potential.

[The odor stick identification test for Japanese (OSIT-J) in a case of coronavirus disease 2019 (COVID-19) without pneumonia]

Anosmia is a frequently experienced symptom in coronavirus disease 2019 (COVID-19). Previous studies have suggested the potential use of olfactometry to identify infected individuals. We performed a sequential olfactometry using the odor stick identification test for Japanese (OSIT-J) in a COVID-19 patient without pneumonia. The test uses 12 odorants that are familiar to the Japanese population. Our patient was a 56-year-old man diagnosed with COVID-19 who was admitted to our hospital following the development of anosmia. He had no respiratory symptoms except pharyngeal pain. Chest CT findings did not reveal the presence of pneumonia. The patient underwent OSIT-J on the 1st hospital day, and his score was 1 out of 12. Following the olfactometry, ciclesonide was administered. The patient did not develop any new symptoms during hospitalization, and his anosmia was gradually improved. The OSIT-J scores were 9 and 11 on the 7th and 16th hospital day, respectively. The patient was discharged on the 25th hospital day after two negative PCR test results. In our case, OSIT-J could identify anosmia in a COVID-19 patient. Some COVID-19 patients are asymptomatic, expect for olfactory disturbances, and OSIT-J may help identify such patients in the Japanese population.

Formation of 3-Methylbutanal and 3-Methylbutan-1-ol Recognized as Malty during Fermentation in Swiss Raclette-Type Cheese, Reconstituted Milk, and de Man, Rogosa, and Sharpe Broth

This work aimed to determine the formation over time of 3-methylbutanal and 3-methylbutan-1-ol recognized as malty during the manufacture of Raclette-type cheese and the fermention of reconstituted skim milk, and filter-sterilized MRS broth. Using dynamic headspace-vacuum transfer in trap extraction followed by gas chromatography coupled with mass spectrometry-olfactometry (DHS-VTT-GC-MS-O) as a screening method for the malty compounds, five compounds (2-methylpropanal, 2- and 3-methylbutanal, and 2- and 3-methylbutan-1-ol) were identified as potential compounds causing the malty aroma in starter culture development and Raclette-type cheeses. Focus on compounds having a predominant sensorial effect (3-methylbutanal and 3-methylbutan-1-ol), spikings of leucine, ¹³C-labeled leucine, α-ketoisocaproic acid, and α-ketoglutaric acid provided a better understanding of their formation pathway. This study highlighted the discrepancies in the formation of 3-methylbutanal and 3-methylbutan-1-ol between the growth media; namely, despite the presence of free leucine available in MRS and the addition of an excess, no increase of the target compounds was observed. The concentration of these compounds in MRS increased only when α-ketoglutaric acid or α-ketoisocaproic acid was added, and a preference for the pathway to α-hydroxyisocaproic acid instead of 3-methylbutanal was shown. In addition, a formation of 3-methylbutanal when the bacteria were not yet active was observed when spiking α-ketoisocaproic acid, which potentially indicates that this part of the metabolism could take place extracellularly. These results could potentially unveil other, not-yet-identified reactants, directly influencing the production of compounds responsible for the malty aroma in Raclette cheese.

Alarm Pheromone Responses Depend on Genotype, but Not on the Presence of Facultative Endosymbionts in the Pea Aphid Acyrthosiphon pisum

Aphids use an alarm pheromone, E-β farnesene (EBF), to warn conspecifics of potential danger. The antennal sensitivity and behavioural escape responses to EBF can be influenced by different factors. In the pea aphid, Acyrthosiphon pisum, different biotypes are adapted to different legume species, and within each biotype, different genotypes exist, which can carry or not Hamiltonella defensa, a bacterial symbiont that can confer protection against natural enemies. We investigate here the influence of the aphid genotype and symbiotic status on the escape behaviour using a four-way olfactometer and antennal sensitivity for EBF using electroantennograms (EAGs). Whereas the investigated three genotypes from two biotypes showed significantly different escape and locomotor behaviours in the presence of certain EBF doses, the infection with H. defensa did not significantly modify the escape behaviour and only marginally influenced the locomotor behaviour at high doses of EBF. Dose-response curves of EAG amplitudes after stimulation with EBF differed significantly between aphid genotypes in correlation with behavioural differences, whereas antennal sensitivity to EBF did not change significantly as a function of the symbiotic status. The protective symbiont H. defensa does thus not modify the olfactory sensitivity to the alarm pheromone. How EBF sensitivity is modified between genotypes or biotypes remains to be investigated.

Odor Canopy: A Method for Comfortable Odorant Delivery in MRI

Functional magnetic resonance imaging (fMRI) has become the leading method for measuring the human brain response to sensory stimuli. However, olfaction fMRI lags behind vision and audition fMRI for 2 primary reasons: First, the olfactory brain areas are particularly susceptible to imaging artifacts, and second, the olfactory stimulus is particularly difficult to control in the fMRI environment. A component of the latter is related to the odorant delivery human–machine interface, namely the point where odorants exit the dispensing apparatus to reach at the nose. Previous approaches relied on either nasal cannulas or nasal masks, each associated with particular drawbacks and discomforts. Here, we provide detailed descriptions and instructions for transforming the MRI head-coil into an olfactory microenvironment, or odor canopy, where odorants can be switched on and off in less than 150 ms without cannula or mask. In a proof-of-concept experiment, we demonstrate that odor canopy provides for clearly dissociable odorant presence and absence, with no nonolfactory cues. Moreover, we find that odor canopy is rated more comfortable than nasal mask, and we demonstrate that using odor canopy in the fMRI generates a typical olfactory brain response. We conclude in recommending this approach for minimized discomfort in fMRI of olfaction.

Profile of Volatile Aroma-Active Compounds of Cactus Seed Oil (Opuntia ficus-indica) from Different Locations in Morocco and Their Fate during Seed Roasting

Volatile compounds from oils extracted from cactus seeds (Opuntia ficus-indica) of five regions of Morocco were analyzed by dynamic headspace-GC/MS. Aroma active compounds were characterized by olfactometry. A total of 18 compounds was detected with hexanal, 2-methyl propanal, acetaldehyde, acetic acid, acetoin and 2,3-butanedione as most abundant. Olfactometric analysis showed that those compounds are aroma active; therefore, cactus seed oil flavor can be attributed to those compounds. Moreover, the effect of roasting of cactus seeds on the composition of volatile compounds in the oil was investigated. Especially the concentration of compounds known as products from the Maillard reaction increased significantly with roasting time such as furfural, furan, 3-methyl furan, 2-butanone, thiophene, 2, 3- dithiabutane, methyl pyrazine, 2-methyl pyrimidine, 2-metoxy phenol, dimethyl trisulfide and 5-methyl furfural.

Effect of Biochar Diet Supplementation on Chicken Broilers Performance, NH3 and Odor Emissions and Meat Consumer Acceptance

The aim of this research was to evaluate the effect of biochar diet supplementation for broiler chickens on (1) ammonia and odor emissions from manure, (2) feed conversion ratio and daily weight gain, and (3) selected meat quality and sensory parameters. Beechwood biochar (BC, 2 and 4%) and BC-glycerin-aluminosilicates mix (BCM, 3 and 6%) were tested as dietary additives. A total of 750 chicken broilers (Ross 308) were divided into five dietary groups with five replicates per group (n = 5, 30 birds in each replicate) and reared on a littered floor for 5 weeks. Both feed additives showed a significant reduction of ammonia emissions by up to 17%, while the reduction of odor emissions was not statistically significant. The feed conversion ratio increased by 8% for the highest concentration of the mixture. The change of the treated broilers' average body weight ranged in the last week of the experiment from 0 to -7%, with the most negative effect for the highest dose of the mixture. Sensory analysis of the sous-vide cooked breasts showed no significant differences.

Subjective and Objective Assessments of Post-traumatic Olfactory Dysfunction

Introduction: Traumatic brain injuries are the most common cause of olfactory dysfunction. Deficits in olfaction may be conductive or neurosensory in nature, with varying degrees of impairment resulting in a diminished quality of life and an increased risk for personal injury among patients. The aim of this research is to evaluate the results of the subjective and objective quantitative examinations of olfactory function in a group of patients with post-traumatic anosmia in order to predict its value in identifying olfactory deficits in clinical practice.

Materials and Methods: The present study included 38 patients who reported anosmia or hyposmia caused by a traumatic head injury, and a group of 31 age- and sex-matched controls without olfactory dysfunction or prior history of head injury. The comparison of odor perception and identification of two oils (mint and anise) was assessed with the use of blast olfactometry with cortical olfactory event-related potentials.

Results: Subjective olfactory tests revealed anosmia or hyposmia in 94% of patients with head injury-related olfactory dysfunction. Objective tests revealed olfactory event-related potentials from cranial nerve I produced by the stimulation with both mint and anise in 20 patients (52.6%). Olfactory event-related potentials from cranial nerve V produced by the stimulation with mint were registered in 26 patients (68.4%). The lack of any responses, from both cranial nerve I and V, was found in 12 patients (32% of cases).

Conclusions: Findings from our study indicate the application of both subjective and objective examinations in the evaluation of patients with olfactory impairment. In the diagnosis of post-traumatic anosmia or hyposmia, objective examinations are particularly useful when the patients' level of cognition may be impaired or when subjects may be exaggerating their olfactory defects for a secondary gain. The diagnosis of damage to the olfactory system, specifically in the receptive part of the olfactory pathway, can be established in patients who showed reduced amplitudes or absent cortical responses in addition to absent odor identification and perception threshold in the subjective examination.

Evaluation of Terpene-Volatile Compounds Repellent to the Coffee Berry Borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae)

The coffee berry borer (CBB) is one of the main coffee pests in the world including Colombia. This pest is difficult to manage because of its cryptic habits and the continuous availability of coffee fruits. Among the new management strategies being tested is the use of volatile compounds as insect repellents. In this work, the behavioral response of female adult CBBs to terpenes previously identified in the CBB-repellent plant species Lantana camara was evaluated. α-Terpinene, (R)-limonene, farnesene and β-caryophyllene terpenes were tested via a Y-tube olfactometer in which ripe coffee fruits were accompanied by terpenes at concentrations between 25 and 200 ppm. Only β-caryophyllene induced a significant and consistent CBB repellent effect at all tested doses. The protective effect of microencapsulated β-caryophyllene was then determined under laboratory conditions by incorporating the terpene in a colloidosome-gel system at 2.8 × 10⁵ ng/h in the middle of coffee fruits with adult CBBs. The coffee fruits in turn presented a decrease in fruit infestation. Furthermore, the protection of coffee fruits when β-caryophyllene gels were hung in coffee trees was evaluated in the field; infestations were artificially induced by the use of raisins (CBB-infested old coffee fruits) placed on the ground. Compared with unprotected trees, the trees treated with caryophyllene gels exhibited a 33 to 45% lower degree of infestation. Taken together, the results show that β-caryophyllene is a promising compound for an integrated pest management (IPM) program in commercial coffee plantations.

Materials Contamination and Indoor Air Pollution Caused by Tar Products and Fungicidal Impregnations: Intervention Research in 2014-2019

Construction materials containing tar products are a source of indoor air pollution in buildings. This particularly concerns old buildings, in which wooden structures were impregnated with tar compositions (creosote oil and Xylamite oil containing tar products) and buildings in which bituminous seal containing hydrocarbon solvents was used. During the 1970s and 1980s, an impregnant known as Xylamite was commonly used in Polish buildings. This material still emits organic vapors into the building’s environment, significantly worsening indoor air quality (IAQ). Xylamites and other impregnating materials are a source of indoor air pollution through toxic organic compounds, such as phenol, cresols, naphthalenes, chlorophenols (CPs), and chloronaphthalenes (CNs), which emit specific odors. TD-GC/MS enables detailed identification of the reasons behind chemical indoor air pollution. The results of laboratory tests on the chemical emissions of bitumen-impregnated materials were presented in 32 case studies. In turn, the results of indoor air pollution by volatile bitumen components were presented on 11 reference rooms and 14 case studies, including residential buildings, office buildings, and others. Laboratory tests of samples of construction products confirmed the main emission sources into indoor air. The research results for the period 2014–2019 are tabulated and described in detail in this manuscript.

Plant Selection for the Establishment of Push-Pull Strategies for Zea mays-Spodoptera frugiperda Pathosystem in Morelos, Mexico

Regulations imposed on the use of chemical insecticides call for the development of environmental-friendly pest management strategies. One of the most effective strategies is the push–pull system, which takes advantage of the behavioral response of the insect to the integration of repellent stimuli; it expels the pest out of the main crop (push), while attracting stimuli (attractants) pull the pest to an alternative crop or trap (pull). The objective of this study was to design a push–pull system to control Spodoptera frugiperda in maize crops (Zea mays) in Morelos, Mexico. Data on reproductive potential, larvae development, food consumption and olfactometry were used to obtain a Trap Plant Selection Index (TRAPS) based on Principal Component Analysis. This TRAPS was used to select the most suitable plants. The degree of repellency of potential plants to be used as the trap crop was studied with four-way olfactometers. S. frugiperda females oviposited more eggs on Brachiaria hybrid cv. Mulato II, Panicum maximum cv. Mombasa and Panicum maximum cv. Tanzania than on Z. mays, regardless of the fact that these plants delayed the development of their offspring. Dysphania ambrosioides, Tagetes erecta and Crotalaria juncea were less attractive to S. frugiperda females. Therefore, the former plants could be used as crop traps, and the latter as intercropped repellent plants in a push–pull system.

Volatiles mediate host-selection in the corn hoppers Dalbulus maidis (Hemiptera: Cicadellidae) and Peregrinus maidis (Hemiptera: Delphacidae)

Volatile organic compounds (VOCs) released by plants are generally involved in host recognition and host selection for many phytophagous insects. However, for leafhoppers and planthoppers, host recognition is mainly thought to involve a phototactic response, but it is not clear if a host plant could be selected based on the volatile cues it emits. In this study we evaluated olfactory responses in dual choice tests of two Hemiptera species, Dalbulus maidis (De Long) (Cicadellidae) and Peregrinus maidis (Ashmead) (Delphacidae), vectors of maize-stunting diseases, to three maize (Zea mays L.) germplasms, a temperate and a tropical hybrid and a landrace. VOCs emitted by the germplasms were collected and identified using gas chromatography-mass spectrometry. The temperate hybrid released significantly more VOCs than the tropical hybrid and the landrace, and its volatile profile was dominated by (±)-linalool. D. maidis preferred odours emitted from the temperate hybrid, whereas P. maidis preferred odours from the tropical hybrid and the landrace over the temperate one. In order to test if linalool plays a role in the behavioural responses, we assayed this compound in combination with the tropical hybrid, to provide other contextual olfactory cues. D. maidis was attracted to the tropical hybrid plus a 0.0001% linalool solution, indicating that this compound could be part of a blend of attractants. Whereas addition of linalool resulted in a slight, though not significant, reduction in host VOC attractiveness for P. maidis. Both hopper species responded to olfactory cues in the absence of supplementary visual cues.

Determination of Various Drying Methods' Impact on Odour Quality of True Lavender (Lavandula angustifolia Mill.) Flowers

True lavender flowers (Lavandula angustifolia Mill.) is a critical source of essential oils and a flavouring agent used in numerous industries like foods, cosmetics and pharmaceuticals. Its main volatile constituents are linalool and linalyl acetate, which are commonly considered as main odour-active constituents (OACs). Nevertheless, the quality of true lavender flowers is highly dependent on its post-harvest treatment, mainly the preservation method. Recognising that drying is the most frequently used preservation method, the influence of various drying methods, including convective drying (CD) at 50, 60 and 70 °C, vacuum-microwave drying (VMD) with powers 240, 360 and 480 W and combined convective pre-drying at 60 °C followed by vacuum-microwave finish-drying with power 480 W (CPD-VMFD), on the quality of true lavender flowers was verified. The evaluation of influence was carried out by HS-SPME(HS, solid-phase microextraction), GC-MS, GC-MS-O (gas chromatography–mass spectrometry–olfactometry) techniques. Moreover, the sensory panel has assessed the sample odour quality. As a result, the optimal drying methods regarding the requirements for products were established. Overall, for total essential oil recovery, CD at 50 °C is the optimal drying method, while for odour quality concerning the sensory panel evaluation, VMD with power 360 W combined CPD-VMFD and CD at 50 °C is the optimal drying method.

Early Olfactory Environment Influences Antennal Sensitivity and Choice of the Host-Plant Complex in a Parasitoid Wasp

Early experience of olfactory stimuli associated with their host-plant complex (HPC) is an important driver of parasitoid foraging choices, notably leading to host fidelity. Mechanisms involved, such as peripheral or central modulation, and the impact of a complex olfactory environment are unknown. Using olfactometer assays, we compared HPC preference of Aphidius ervi Haliday (Hymenoptera:Braconidae) females originating from two different HPCs, either with the other HPC in close vicinity (complex environment) or without (simple environment). We also investigated antennal responses to volatiles differentially emitted by the two respective HPCs. In a simple environment, HPC of origin had an influence on olfactory choice, but the preferences observed were asymmetric according to parasitoid origin. Electroantennographic recordings revealed significant sensitivity differences for some of the tested individual volatiles, which are emitted differentially by the two HPCs. Besides, presence of an alternative HPC during early stages modified subsequent parasitoid preferences. We discuss how increased olfactory complexity could influence parasitoid host foraging and biological control in diversified cropping systems.

Characterization of aroma, aroma-active compounds and fatty acids profiles of cv. Nizip Yaglik oils as affected by three maturity periods of olives

BACKGROUND

The present study aimed to investigate how olive maturity indices (MI) (2.5, 3.5 and 4.5 MI) affect the aroma, aroma-active compounds, fatty acid profiles and color properties of cv. Nizip Yaglik olive oils. Various techniques for extracting volatiles from oil materials are available in the literature. Aroma compounds were extracted by the solvent-assisted flavor evaporation extraction method for the first time in olive oil.

RESULTS

The type and number of aroma-active compounds varied according to maturity periods of olives. A total of 22, 21 and 20 different key odorants were found in aromatic extracts of samples with 2.5, 3.5 and 4.5 MI, respectively. The most potent aroma-active compounds based on flavor dilution (FD) factor values were hexanal (green) for 2.5 MI (FD: 1024) and 3.5 MI (FD: 512), as well as 1-penten-3-ol (green-leafy) for 4.5 MI (FD: 512).

CONCLUSION

Overall, olive oils obtained from unripe and medium-ripe olives had stronger green and fruity odours compared to ripe olives. Principal component analysis demonstrated that oils were clearly discriminated according to their general physicochemical analysis, fatty acids, aroma profiles and key odorants. The results of the present study show that the olive maturity period has a significant influence on the quality parameters of olive oil. © 2018 Society of Chemical Industry.

Effects of Harvest Time on the Aroma of White Wines Made from Cold-Hardy Brianna and Frontenac Gris Grapes Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry-Olfactometry

The Midwest wine industry has shown a marked increase in growers, hectares planted, wineries, and wine production. This growth coincides with the release of cold-hardy cultivars such as Brianna and Frontenac gris, in 2001 and 2003, respectively. These white grape varieties account for one-third of the total area grown in the state of Iowa. It is generally accepted that the wine aroma profile plays a crucial role in developing a local, sustainable brand. However, the identity of Brianna/Frontenac Gris-based wine aromas and their link to the grape berry chemistry at harvest is unknown. This study aims to preliminarily characterize key odor-active compounds that can influence the aroma profile in wines made from Brianna and Frontenac gris grapes harvested at different stages of ripening. Brianna and Frontenac gris grapes were harvested approximately 7 days apart, starting at 15.4 °Brix (3.09 pH) and 19.5 °Brix (3.00 pH), respectively. Small batch fermentations were made for each time point with all juices adjusted to the same °Brix prior to fermentation. Odor-active compounds were extracted from wine headspace using solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS) and simultaneous olfactometry (O). Over 30 odor-active compounds were detected. Aromas in Brianna wines developed from “cotton candy” and “floral”, to “banana” and “butterscotch”, then finally to “honey”, “caramel” and an unknown neutral aroma. Frontenac gris wines changed from an unknown neutral aroma to “fruity” and “rose”. Results from the lay audiences’ flavor and aroma descriptors also indicate a shift with harvest date and associated °Brix. To date, this is the first report of wine aromas from Brianna and Frontenac gris by GC-MS-O. Findings from this research support the hypothesis that aroma profiles of Brianna and Frontenac gris wines can be influenced by harvesting the grapes at different stages of ripening.

Submerged Cultivation of Pleurotus sapidus with Molasses: Aroma Dilution Analyses by Means of Solid Phase Microextraction and Stir Bar Sorptive Extraction

The basidiomycete Pleurotus sapidus (PSA) was grown in submerged cultures with molasses as substrate for the production of mycelium as a protein source for food applications. The volatilomes of the substrate, the submerged culture, and the mycelia were analyzed by gas chromatography-tandem mass spectrometry-olfactometry. For compound identification, aroma dilution analyses by means of headspace solid phase microextraction and stir bar sorptive extraction were performed via variation of the split vent flow rate. Among the most potent odorants formed by PSA were arylic compounds (e.g., p-anisaldehyde), unsaturated carbonyls (e.g., 1-octen-3-one, ( E)-2-octenal, ( E, E)-2,4-decadienal), and cyclic monoterpenoids (e.g., 3,9-epoxy- p-menth-1-ene, 3,6-dimethyl-3a,4,5,7a-tetrahydro-1-benzofuran-2(3 H)-one). Several compounds from the latter group were described for the first time in Pleurotus spp. After separation of the mycelia from the medium, the aroma compounds were mainly enriched in the culture supernatant. The sensory analysis of the mycelium correlated well with the instrumental results.

Olfactory phenotypic expression unveils human aging

The mechanism of the natural aging of olfaction and its declinein the absence of any overt disease conditions remains unclear. Here, we investigated this mechanism through measurement of one of the parameters of olfactory function, the absolute threshold, in a healthy population from childhood to old age. The absolute olfactory threshold data were collected from an Italian observational study with 622 participants aged 5-105 years. A subjective testing procedure of constant stimuli was used, which was also compared to the ‘staircase’ method, with the calculation of the reliability. The n-butanol stimulus was used as an ascending series of nine molar concentrations that were monitored using an electronic nose. The data were analyzed using nonparametric statistics because of the multimodal distribution. We show that the age-related variations in the absolute olfactory threshold are not continuous; instead, there are multiple olfactory phenotypes. Three distinct age-related phenotypes were defined, termed as ‘juvenile’, ‘mature’ and ‘elder’. The frequency of these three phenotypes depends on age. Our data suggest that the sense of smell does not decrease linearly with aging. Our findings provide the basis for further understanding of olfactory loss as an anticipatory sign of aging and neurodegenerative processes.

Characterization of odorous contaminants in post-consumer plastic packaging waste using multidimensional gas chromatographic separation coupled with olfactometric resolution

The increasing world population with their growing consumption of goods escalates the issue of sustainability concepts with increasing demands in recycling technologies. Recovery of post-consumer packaging waste is a major topic in this respect. However, contamination with odorous constituents currently curtails the production of recycling products that meet the high expectations of both consumers and industry. To guarantee odor-free recyclates, the main prerequisite is to characterize the molecular composition of the causative odorants in post-consumer plastic packaging waste. However, targeted characterization of odorous trace contaminants among an abundance of volatiles is a major challenge and requires specialized and high-resolution analytical approaches. For this aim, post-consumer packaging waste was characterized by sensory analysis and two-dimensional high resolution gas chromatography coupled with mass spectrometry and olfactometry. The 33 identified odorants represent various structural classes as well as a great diversity of smell impressions with some of the compounds being identified in plastics for the first time. Substances unraveled within this study provide insights into sources of odorous contamination that will require specific attention in the future in terms of screening and prevention in recycling products.

Male Psyllids Differentially Learn in the Context of Copulation

In the Asian citrus psyllid, Diaphorina citri Kuwayama, stimulatory cuticular hydrocarbons act as sex pheromone attractants. Male psyllids locate aggregations of females using those olfactory cues, as well as vibrational communication on the plant surface. Although previous research has indicated that learning plays a role in modulating female reproductive behaviors in psyllids, it is unknown whether males similarly use learning to increase the likelihood of copulatory success. We used an olfactometer-based bio-assay to study the effects of experience on male response to female odor. First, we compared male attraction to female odor in virgin and previously mated males. Second, we tested the effect of several modes of experience with a novel odor, vanillin, to determine whether mating, feeding, or general environmental exposure elicited a learned response. We found that male attraction to female odor significantly increased after mating experience. In addition, we found that males learn about odor specifically in the context of mating, rather than feeding or general exposure. Electrophysiological measurements of antennal response to odorants confirmed that mating status did not affect the sensitivity of the peripheral nervous system to volatile stimuli implicating learning at the level of the central nervous system. These results suggest that male response to female odor is not an entirely innate behavior. Males may require mating experience with female conspecifics to develop attraction to those olfactory cues produced by the female and in association with the female’s habitat. This adaptive plasticity may allow males to detect females in an ever-changing environment and promote diversification and further specialization on different host genotypes.

Larval Performance and Adult Attraction of Delia platura (Diptera: Anthomyiidae) in a Native and an Introduced Crop

Delia platura Meigen is an important pest in crops around the world. Its host range includes almost 50 species, and it can develop in soil organic matter. In Ecuador, D. platura is a serious problem for the crop, Lupinus mutabilis Sweet (Chocho), and it also attacks broccoli (Brassica oleracea L.). After broccoli is harvested, crop residue is mixed with soil or collected and stored close to Chocho fields. The objectives of this study were to determine the adaptive responses of larvae reared on different hosts and whether D. platura females are preferentially attracted to germinating L. mutabilis seeds or broccoli residue. Accordingly, larval performance and attraction of female D. platura reared on broccoli residue and L. mutabilis seeds were evaluated. The number of larvae, pupae, and adults were higher when reared on broccoli. Conversely, pupal weight was higher and time from larva to pupa, pupa to adult, and total life cycle were longer in flies reared on L. mutabilis. Although D. platura developed more quickly on broccoli, L. mutabilis was also a good host since pupae were heavier compared with flies reared on broccoli. Delia platura females reared on broccoli preferred broccoli residue to L. mutabilis in an olfactometer. Volatiles from broccoli residue in soil may attract D. platura females and stimulate oviposition on L. mutabilis seeds. Environmentally benign production of L. mutabilis crops with minimal insecticide applications may require the elimination of fresh broccoli residue as fertilizer in soils where L. mutabilis is cultivated.

Impact of Brassica and Lucerne Finishing Feeds and Intramuscular Fat on Lamb Eating Quality and Flavor. A Cross-Cultural Study Using Chinese and Non-Chinese Australian Consumers

Use of forage brassicas (Brassica napus) and lucerne (alfalfa; Medicago sativa) as ruminant feeds has been linked to unacceptable flavors in sheepmeat. Lambs from low and high intramuscular fat sires were allocated to one of four finishing feeds-perennial ryegrass (Lolium perenne), lucerne, and two brassica forages-for a 6 week period. Grilled loins (Longissimus thoracis et lumborum) were subjected to chemical and sensory analysis by a trained panel and also evaluated by non-Chinese and Chinese background Australian consumers. Consumer liking was similar for both groups, and liking was highest for the brassica- and lucerne-finished lamb, especially from high intramuscular fat sires. No evidence of a distinctive lucerne- or brassica-induced flavor taint was measured by the trained panel or gas chromatography-mass spectrometry-olfactometry. The diets influenced the composition of lipids and branched-chain fatty acids in the subcutaneous fat, and the concentration of total branched-chain fatty acids was positively correlated with flavor and overall liking. Significantly higher levels of key aroma volatiles were measured in the higher fat samples.

Sensory and Flavor Chemistry Characteristics of Australian Beef: Influence of Intramuscular Fat, Feed, and Breed

The sensory attributes and flavor chemistry of grilled beef striploins (M. longissimus lumborum, n = 42) varying widely in marbling from commercial production types typical for Southern Australia were extensively characterized. Striploins from Angus grass-fed yearlings (5.2-9.9% intramuscular fat), Angus grain-finished steers (10.2-14.9%), and Wagyu grass-fed heifers (7.8-17.5%) were evaluated. Inherent differences between samples from grass- and grain-fed Angus cattle were minimal when the intramuscular fat content was above ∼5%. After adjusting for intramuscular fat, Wagyu samples had more intense flavor and higher tenderness and juiciness compared to Angus grass-fed samples. Grilled beef flavor, dairy fat, and sweetness increased with the marbling level, and sourness and astringency decreased. Tenderness and juiciness increased with the marbling level and were correlated with Warner-Bratzler peak force measurements. Trained panel sensory differences in flavor corresponded with increases in aroma volatiles and changes in nonvolatile flavor compounds. Unsaturated fatty acids with potential health benefits (vaccenic, oleic, and rumenic acids) increased with the level of marbling.

The Use of Sensory Analysis Techniques to Assess the Quality of Indoor Air

The quality of indoor air is one of the significant elements that influences people's well-being and health inside buildings. Emissions of pollutants, which may cause odor nuisance, are the main reason for people's complaints regarding the quality of indoor air. As a result, it is necessary to perform tests aimed at identifying the sources of odors inside buildings. The article contains basic information on the characteristics of the sources of indoor air pollution and the influence of the odor detection threshold on people's health and comfort. An attempt was also made to classify and use sensory analysis techniques to perform tests of the quality of indoor air, which would enable identification of sensory experience and would allow for indication of the degree of their intensity.

Characterization of Atypical Off-Flavor Compounds in Natural Cork Stoppers by Multidimensional Gas Chromatographic Techniques

Natural cork stoppers with sensory deviations other than the typical cork taint were subgrouped according to their sensory descriptions and compared with unaffected control cork stoppers. The assessment of purge and trap extracts obtained from corresponding cork soaks was performed by heart-cut multidimensional gas chromatography-olfactometry (MDGC-O). The identification of compounds responsible for atypical cork taint detected in MDGC-O was further supported with additional multidimensional GC analysis in combination with mass spectrometric detection. Geosmin and 2-methylisoborneol were mainly found in cork stoppers described as moldy and cellarlike; 3-isopropyl-2-methoxypyrazine and 3-isobutyl-2-methoxypyrazine were found in cork stoppers described with green attributes. Across all cork subgroups, the impact compound for typical cork taint, 2,4,6-trichloroanisole (TCA), was present and is therefore a good marker for cork taint in general. Another potent aroma compound, 3,5-dimethyl-2-methoxypyrazine (MDMP), was also detected in each subgroup, obviously playing an important role with regard to the atypical cork taint. Sensory deviations possibly affecting the wine could be generated by MDMP and its presence should thus be monitored in routine quality control.

Olfactory basis of floral preference of the malaria vector Anopheles gambiae (Diptera: Culicidae) among common African plants

Mosquitoes of both sexes feed on plants to obtain sugar. Nocturnal species probably locate the plants primarily by their volatile semiochemicals that also form the basis for the mosquitoes' innate plant-species preferences. To evaluate these olfactory preferences quantitatively, we used a two-choice wind-tunnel olfactometer to measure the upwind orientation of Anopheles gambiae Giles, an important vector of malaria in equatorial Africa, toward odor plumes produced by nine plant species common where this mosquito occurs. These plants are reported to induce feeding behaviors in An. gambiae and to produce floral or extrafloral nectar. Results presented here demonstrated that the volatiles of S. didymobotrya, P. hysterophorus, S. occidentalis, and L. camara, in descending order of numbers of mosquitoes responding, were all attractive, compared to a control plant species, whereas D. stramonium, R. communis, S. bicapsularis, T. stans, and T. diversifolia were not. As expected, chromatographic analysis of the headspace of attractive plants whose volatiles were captured by stir-bar sorptive extraction revealed a wide range of compounds, primarily terpenoids. Once their bioactivity and attractiveness for An. gambiae, alone and in blends, has been firmly established, some of these semiochemicals may have applications in population sampling and control.

Odorant synergy effects as the cause of fishy malodors in algal marine oils

As unsaturated lipids oxidize, they form hydroperoxides, which are susceptible to further oxidation or decomposition to secondary reaction products including aldehydes, ketones, acids, and alcohols. While oxidation reactions of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are responsible for fishy off-flavors in marine oils, gas chromatography-olfactometry (GC-O) and other types of analytical studies have failed to reveal which specific oxidation products are involved. Previous research (Marsili, R.T.; Laskonis, C. The importance of odourant synergy effects in understanding malodour problems in DHA and EPA products. Lipid Technol. 2014, 26 (2), 31-34) has indicated that fishy malodor may be caused by the presence of two lipid oxidation products, heptanal and (E,Z)-3,5-octadien-2-one. The aims of the present study are to provide experimental method details and offer further evidence that these two oxidation products are indeed the cause of fishy malodors. Initial GC-MS-O studies of marine oils with fishy malodors revealed numerous oxidation products, but none were characterized as fishy. However, when all sample volatiles were captured together and then desorbed simultaneously in GC-O experiments, the fishy malodor was evident, indicating odorant synergy effects were responsible. A simple, novel method was developed using an olfactometry detector as a fraction collector to trap various peaks in marine oil chromatograms. The nose cone of the olfactometry detector was replaced with a PDMS foam absorption tube at various times during GC analysis. Combinations of GC peaks were trapped on PDMS tubes, desorbed in a Gerstel thermal extractor (off-line), and sniffed. The combination of two analytes was found to cause fishy malodors: heptanal and (E,Z)-3,5-octadien-2-one. Purge-and-trap, solid phase microextraction (SPME), and headspace stir bar sorptive extraction (HSSE) sample preparation methods prior to GC-MS were investigated. All methods confirmed the combination of heptanal and (E,Z)-3,5-octadien-2-one as the cause of fishy odor.

Identification of potent odorants in a novel nonalcoholic beverage produced by fermentation of wort with shiitake (Lentinula edodes)

Novel refreshments with pleasant flavors were developed by fermentation of wort with basidiomycetes. Among 31 screened fungi, shiitake (Lentinula edodes) produced the most pleasant flavor. It was perceived as fruity, slightly sour, and plum-like. Flavor compounds were isolated by liquid-liquid extraction (LLE) and by headspace solid phase microextraction (HS-SPME). The key odor-active compounds were analyzed by a gas chromatography system equipped with a tandem mass spectrometry detector and an olfactory detection port (GC-MS/MS-O) and aroma extract dilution analysis (AEDA). For HS-SPME, a revised method of increasing the GC inlet split ratio was used. Most of the key odor-active compounds (e.g., 2-acetylpyrrole, β-damascenone, (E)-2-nonenal, and 2-phenylethanol) were detected with both extraction techniques. However, distinct differences between these two methods were observed.

Analytical methods for chemical and sensory characterization of scent-markings in large wild mammals: a review

In conjoining the disciplines of "ethology" and "chemistry" the field of "Ethochemistry" has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus), puma (Puma concolor) snow leopard (Panthera uncia), African lions (Panthera leo), cheetahs (Acinonyx jubatus), and tigers (Panthera tigris)) for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal's sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior.

Characterization of the key aroma compounds in Turkish olive oils from different geographic origins by application of aroma extract dilution analysis (AEDA)

The aroma and aroma-active compounds of olive oils obtained from Nizip Yaglik (NY) and Kilis Yaglik (KY) cultivars and the effect of the geographical area (southern Anatolian and Aegean regions) on these compounds were analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). For this purpose, two oil samples were obtained from their native geographical area including NY from Nizip province and KY from Kilis province (southern Anatolian region of Turkey). Another two oils of the same cultivar, NY-Bornova (NY-B) and KY-Bornova (KY-B), were obtained from the Olive Oil Research Center-Bornova, Izmir province (Aegean region of Turkey) to compare geographical effect on aroma and aroma-active compounds. Simultaneous distillation and extraction (SDE) with dichloromethane was used for extraction of volatile components. SDE gave a highly representative aromatic extract of the studied olive oil based on the sensory analysis. Totals of 61, 48, 59, and 48 aroma compounds were identified and quantified in olive oils obtained from NY, NY-B, KY, and KY-B cultivars, respectively. The results of principal component analysis (PCA) showed that the aroma profile of native region oils was discriminately different from those of Bornova region oils. Aldehydes and alcohols were qualitatively and quantitatively the most dominant volatiles in the oil samples. Aroma extract dilution analysis (AEDA) was used for the determination of aroma-active compounds of olive oils. The number of aroma-active compounds in native region oils was higher than in Bornova region oils. Within the compounds, aldehydes and alcohols were the largest aroma-active compounds in all olive oils.

Host-habitat location by the parasitoid, Nasonia vitripennis Walker (Hymenoptera: Pteromalidae)

This study investigated the role of odorant cues used during host-habitat location by the generalist parasitoid, Nasonia vitripennis Walker. Nasonia vitripennis is a common parasitoid of Dipteran pupae found in association with decaying carrion. Behavioral assays were used to investigate the host-habitat searching behavior under different scenarios. First, we demonstrated N. vitripennis to be significantly attracted toward odorant cues associated with decaying meat. The biological activity of nine of the volatile molecules constituting the odor of decaying meat was tested on the searching behavior of parasitoid females through two complementary chemoecological approaches: electroantennography (EAG) and olfactometry bioassays. Butanoic acid and butan-1-ol elicited high olfactory responses, but no attraction was induced by these two chemicals. Behavioral assays showed that, among the VOCs tested, methyldisulfanylmethane (DMDS) was the only volatile chemical to induce attraction in N. vitripennis.