Odor Components Research Articles

Are there olfactory evoked alterations of breathing patterns?

It is controversially discussed whether strictly olfactory stimuli are able to evoke changes of breathing patterns. A number work groups argue that the more or less noticeable irritative component of odors are responsible for a respiratory response. Other work groups regard changes of breathing pattern as an indicator for an intact smell ability during "pure" olfactory stimulation. 12 normosmic young volunteers were repeatedly challenged with hydrogensulfide (H (2)S) for two seconds on inspiration in concentrations just above the threshold using a flow olfactometer. Clean air stimuli were presented randomly as control blanks. The breathing patterns were registered with a differential pressure transducer occluding one nostril via a tube. The signals were digitized and recorded on a PC. Nine parameters were calculated for each breath using a custom made LabView (R) software. The breath during stimulation was compared to the average of five breathing cycles prior to stimulation. An increase or reduction of each parameter was equally regarded by means of their absolute value. The sum was termed respiration index (RI). The mean RI (all trials of each test person) stimulated with H (2)S varied from 201 to 570; stimulated with clean air from 85 to 188. The difference was significant (p < 0,001). A significant group-difference for each single trial was seen as well. There was no significant increase or decrease of RI during 15 successive stimulations with H (2)S. Detectable short H (2)S-stimuli are able to evoke alterations of breathing patterns which can be identified by computer. Respiration-olfactometry is suitable to objectify odor perception.

Primer effects by conspecific odors in house mice: a new perspective in the study of primer effects on reproductive activities

Half a century has passed since the first report of the influence of odors on mice. Odors are known to influence behavior (signaling effect) and affect the physiology (primer effect) of mice. This review focuses on summarizing the primer effects found so far in female and male mice. Odors from conspecifics of the opposite sex had the tendency to enhance reproductive activities, whereas odors from conspecifics of the same sex diminish them. Only 2,5-dimethylpyrazine, one of the odor components identified in group-housed females, has been reported to have a suppressive influence on both males and females by lowering reproductive activities. Studies showed progress from the discovery of phenomena to the identification of odor components that cause such changes in reproductive organs and related neuroendocrinological changes. Compared to studies on the mechanisms of primer effects in females, the mechanisms in males are not yet clarified, and detailed studies on effects on the reproductive organs are still in primitive stages especially for males. Hypotheses on the influence of changes in the concentration of testosterone, estrogen, and prolactin on spermatogenesis and sperm maturation after exposure to odors are discussed.

Who Steals the Eggs? Coprophanaeus Telamon (Erichson) Buries Decomposing Eggs in Western Amazonian Rain Forest (Coleoptera: Scarabaeidae)

The necrophagous dung beetle Coprophanaeus telamon (Erichson 1847) buried decomposing hen eggs in the rain forest of Ecuador. We suppose that the volatiles 2-butanone, cresol, indole, skatole, and butyric acid are responsible for attracting Coprophanaeus because these components of dung odour attract dung beetles and are also present in rotten eggs. A number of them are also produced by bacterial spoilage of raw meat. Abandoned clutches, infertile eggs or eggs with dead embryos of ground-nesting birds may be used as a resource by dung beetles.

Odor of Taste Stimuli in Conditioned "Taste" Aversion Learning.

The present research addresses whether rats can express odor aversions to the odor of taste stimuli. In Experiment 1, saccharin or salt were either mixed in distilled water, so the rats could taste and smell them, or presented on disks attached to the tubes' metal spouts so the rats could only smell them. Aversions were established to taste stimuli under both conditions. The results of Experiment 2 indicate that conditioning was to the odor of the tastes when they were presented on disks in Experiment 1, hence both taste and odor aversions were established by means of "taste" stimuli. Taste aversion learning thus may more properly be termed flavor aversion learning, with flavor referring to both taste and odor components.

Chemistry Perfumes Your Daily Life

The use of perfumes can be tracked back to many early civilizations. Historically, perfumes were composed exclusively of natural ingredients, mainly essential oils, and were reserved for the wealthiest people. The use of synthetic ingredients marked the beginning of modern perfumery at the end of the 19th century. Nowadays, perfumes are available to everyone and are present in a wide range of consumer goods. The methods used to extract perfume ingredients from their natural sources have changed over time as technology has advanced. Depending on the material, expression, distillation, and solvent extraction are the main techniques used to extract the odorant components from a natural source. Synthetic organic chemistry has provided perfumers with novel ingredients that are cheaper and more stable than many natural materials over the years. Today, more than 3000 fragrance ingredients are estimated to be available to perfumers to create a harmonious composition of head (for example, citrusy), heart (for exam...

Characteristic odor components of Citrus reticulata Blanco (ponkan) cold-pressed oil.

Citrus reticulata Blanco (ponkan) cold-pressed oil and its oxygenated fraction were studied by analytical (GC and GC/MS) and sensory analyses. The monoterpene group was predominant, accounting for more than 89.6% (w/w), of which limonene was the most abundant (80.3%). Among the oxygenated compounds, octanal and decanal were the major ones among 12 aldehydes accounting for >1.5%; six alcohols were identified with a total concentration of >0.7%, while oxides, ketones and esters did not quantitatively or qualitatively contribute to the oil. Sniffing the ponkan cold-pressed oil and its oxygenated fraction demonstrated that octanal and decanal were the characteristic odor components of ponkan. Reconstruction of the ponkan aroma model and its sensory evaluation by a hedonic test were performed, showing that, in addition to octanal and decanal which played important roles, (R)-(+)-limonene contributed to the aroma model as a background component, making the aroma model very similar to that of the original.

Determination of Chemical Components that Cause Mal-Odor from Natural Rubber

Abstract Odorous components emitted from different forms of solid natural rubber (NR) were analyzed using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) associated with head space sampling technique. The most odorous components from most samples were identified as low molecular weight volatile fatty acids (C2-C5). Other volatile organic contents verified based on characteristic ions of mass spectra included carbonyl compounds, low molecular weight compounds containing nitrogen or sulfur and aromatic compounds. The total content and composition of volatile organic compounds were directly correlated to the rubber quality and drying process. Low-grade NR samples, i.e. STR 20 from cup lumps with intense smell, had high quantity of volatile organic contents especially low molecular weight volatile fatty acids. On the other hand, high-quality rubber, i.e. deproteinized NR and STR 5L from which no smell was detected, contained only minute quantities of volatile organic contents. Aromatic components were regarded as other major odorous contents found in ribbed smoked sheet (RSS) samples. The results suggested that the odorous components were the by-products of non-rubber components which had undergone microbial breakdown during storage or thermal degradation during processing.

Morphological and Functional Flower Characteristics of New and Old World Annonaceae with Respect to Their Mode of Pollination

The Annonaceae show a broader flower biological radiation than originally thought, with flowers being pollinated not only by beetles, but also by thrips, flies and even bees. The majority of species have hermaphroditic protogynous flowers. Species with white or yellowish-white, small, delicate, day-active flowers, may be pollinated either solely by thrips, or by thrips and small beetles (e.g., species of Bocageopsis, Oxandra, Xylopia). Several of these thrips-pollinated species have stamens with an elongated, tongue-like connective. Pollination by flies is not well documented for American species, notwithstanding it appears to be more common in Old World species, e.g., in the genus Pseuduvaria. The mitriform flowers exhale an unpleasant smell, produce nectar in purple-colored petal glands and have a sapromyiophilous syndrome. Flies enter the flower center through large openings between the inner petals. Beetle-pollinated Annonaceae have flowers with comparatively thick and, often, fleshy petals, which, during anthesis frequently form a pollination chamber with the petals inclining over the flower center. The stamens usually have peltate connective shields, probably a device for protection against voracious beetles. Some cantharophilous species have flowers which are day-active while others are night-active. When they are in their pistillate phase, the beetles are attracted by characteristic odor components. They enter the pollination chamber and usually remain in the interior of the flower until the flower has changed to its staminate phase, when pollen is shed and afterwards petals and stamens detach. Two lines of cantharophilous Annonaceae are recognizable on the basis of present knowledge. Species with smaller and more delicate flowers are pollinated by small beetles (Nitidulidae, Curculionidae, Chrysomelidae and Staphylinidae), whereas species with large, more robust flowers in the Neotropics are pollinated by large beetles of the family Scarabaeidae, subfamily Dynastinae. Some species of the cantharophilous Annonaceae, especially the large-flowered ones, but also some species with smaller flowers, produce heat during anthesis (thermogenesis). Food bodies, developed on the adaxial surfaces or sides of the petals, provide unique nourishment possibilities for beetles when they stay inside the flowers during the pistillate phase. In the staminate stage of the flower, after pollen is shed, beetles also feed on pollen. Apparently, no dynastid-flower relationship has evolved in Asia and Australia. Pollination by bees was discovered recently in Unonopsis guatterioides in Amazonia and Uvaria concava in North Queensland: the first by scent-collecting euglossine males and the second by pollen-collecting Meliponinae. The general trends in morphological/functional floral characteristics in the family are discussed in a presumptive phylogenetic context.

Morphological and functional flower characteristics of New and Old World Annonaceae with respect to their mode of pollination

The Annonaceae show a broader flower biological radiation than originally thought, with flowers being pollinated not only by beetles, but also by thrips, flies and even bees. The majority of species have hermaphroditic protogynous flowers. Species with white or yellowish‐white, small, delicate, day‐active flowers, may be pollinated either solely by thrips, or by thrips and small beetles (e.g., species of Bocageopsis, Oxandra, Xylopia). Several of these thrips‐pollinated species have stamens with an elongated, tongue‐like connective. Pollination by flies is not well documented for American species, notwithstanding it appears to be more common in Old World species, e.g., in the genus Pseuduvaria. The mitriform flowers exhale an unpleasant smell, produce nectar in purple‐colored petal glands and have a sapromyiophilous syndrome. Flies enter the flower center through large openings between the inner petals. Beetle‐pollinated Annonaceae have flowers with comparatively thick and, often, fleshy petals, which, during anthesis frequently form a pollination chamber with the petals inclining over the flower center. The stamens usually have peltate connective shields, probably a device for protection against voracious beetles. Some cantharophilous species have flowers which are day‐active while others are night‐active. When they are in their pistillate phase, the beetles are attracted by characteristic odor components. They enter the pollination chamber and usually remain in the interior of the flower until the flower has changed to its staminate phase, when pollen is shed and afterwards petals and stamens detach. Two lines of cantharophilous Annonaceae are recognizable on the basis of present knowledge. Species with smaller and more delicate flowers are pollinated by small beetles (Nitidulidae, Curculionidae, Chrysomelidae and Staphylinidae), whereas species with large, more robust flowers in the Neotropics are pollinated by large beetles of the family Scarabaeidae, subfamily Dynastinae. Some species of the cantharophilous Annonaceae, especially the large‐flowered ones, but also some species with smaller flowers, produce heat during anthesis (thermogenesis). Food bodies, developed on the adaxial surfaces or sides of the petals, provide unique nourishment possibilities for beetles when they stay inside the flowers during the pistillate phase. In the staminate stage of the flower, after pollen is shed, beetles also feed on pollen. Apparently, no dynastid‐flower relationship has evolved in Asia and Australia. Pollination by bees was discovered recently in Unonopsis guatterioides in Amazonia and Uvaria concava in North Queensland: the first by scent‐collecting euglossine males and the second by pollen‐collecting Meliponinae. The general trends in morphological/functional floral characteristics in the family are discussed in a presumptive phylogenetic context.

Characteristic odour components of Citrus sp. (Kiyookadaidai) cold‐pressed peel oil

AbstractThe volatile components of Citrus sp. (Kiyookadaidai) cold‐pressed peel oil were investigated by chemical and sensory analyses. Monoterpene hydrocarbons were abundant, accounting for more than 90.2% of the total content. Myrcene was determined to be the predominant monoterpene hydrocarbon (62.4%), rather than limonene, which is usually reported as most abundant in citrus cold‐pressed oils. The weight percentages of alcohols, aldehydes and esters were &gt;1.0%, &gt;0.8% and &gt;0.8%, respectively. Forty‐seven aroma‐active compounds were detected in Kiyookadaidai oil using GC–O and AEDA. Myrcene, (Z)‐ocimene and α‐bergamotene were the odour‐characteristic compounds, creating a Kiyookadaidai‐like odour. A model solution prepared from one certain con‐centration of myrcene, limonene and (Z)‐ocimene yielded the refreshing and characteristically green aroma of Kiyookadaidai cold‐pressed oil. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Effect of sunlight exposure and aging on skin surface lipids and urate

Free fatty acids (FFA), squalene, squalene hydroperoxide, and uric acid in the methanol extracts from human skin surface were measured. Levels of FFA and squalene were significantly lower in the older (83.7 +/- 9.4 years) than in the younger (22.2 +/- 3.9 years) group. FFA are mostly saturated, and linoleic acid is an exclusive polyunsaturated fatty acid. The composition of linoleic acid decreased in the older group by 40%, suggesting age-dependent loss of oxidatively vulnerable polyunsaturated fatty acid. Even monounsaturated acids such as palmitoleic and oleic acids decreased significantly in the older group. This could be interesting because 2-nonenal is the oxidation product of palmitoleic acid and has been identified as the major aged body odor component. Sunlight exposure for 1.5 h did not change levels of FFA and squalene, or FFA composition. However, squalene hydroperoxide increased by 60-fold, as reported previously, suggesting that hydroperoxide is produced by singlet oxygen. Uric acid increased by two-fold, which may be the adaptive response against photo-oxidative stress because uric acid is a good scavenger of singlet oxygen and oxygen radicals.

Honey bee (Hymenoptera: Apidae) foraging in response to preconditioning with onion flower scent compounds.

Onion (Allium cepa L.) seed production has long been plagued with yield problems because of lack of pollination by the honey bee, Apis mellifera L. To attempt to attract more pollinators to the onion seed production field, honey bees were conditioned to associate onion floral odor components with a reward. Isolated nucleus hives of honey bees were fed 30% sucrose solutions scented with a 0.2% solution of onion floral odor compounds. After feeding on these solutions for 6 wk, bees were not found to prefer onion flowers to two competing food sources, carrot and alfalfa flowers, at the 5% significance level. However, there was an overall trend indicating a change in honey bee behavior, with fewer "trained" bees visiting alfalfa and carrot and more visiting onion. Thus, it may be possible to alter honey bee behavior with preconditioning but probably not to a degree that would be economically significant.

Characteristic odour components of Citrus inflata Hort. ex Tanaka (Mochiyu) cold‐pressed peel oil

AbstractCharacteristic odour components of Citrus inflata Hort. ex Tanaka (Mochiyu) were studied by sensorial and instrumental techniques. Flavour dilution (FD) factor and relative flavour activity (RFA) of individual volatile components were evaluated by aroma extraction dilution analysis (AEDA) and gas chromatography–olfactometry (GC–O). The results indicated that hydrocarbons (98.1%) made up most of the oil: monoterpenes and sesquiterpenes were 97.6% and 0.5%, respectively. Among oxygenated compounds, linalool (0.2%) as an alcohol, perillaldehyde (0.1%) and tridecanal (0.1%) as aldehydes showed relatively high quantities, while the others were all less than 0.05%. AEDA and GC–O indicated that myrcene, (E)‐ocimene, cis‐linalool oxide, trans‐linalool oxide, β‐copaene, perillaldehyde and perillyl alcohol were the odour characteristic compounds, showing Mochiyulike odour. Careful sniff testing revealed that (E)‐ocimene could be an key odour compound of Mochiyu aroma. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Fundamental study of odor recorder for multicomponent odor using recipe exploration method based on singular value decomposition

A new method for the odor recorder, electronically recording the recipe of odors or scents made up of many components, was proposed. Although apple flavors have been recorded with a mixture of five components using the odor recorder in previous work, the number of odor components should be increased to expand the applicable range of odors. Since the collinearity problem of the odor sensor array became apparent with the increase of components, a new method based on variable transformation using singular value decomposition was developed in this paper, to extract the effective subspace of the sensor outputs for recipe exploration. As a result, the sensor-array response pattern of the reproduced odor, with the eight-component recipe, almost agreed with that of the target apple flavor. Furthermore, human sensory tests revealed that the smell of the approximated odor was identical to that of the target flavor.

Online measurement of odorous gases close to the odour threshold with a QMB sensor system with an integrated preconcentration unit

Today odour measurement close to the odour threshold can be performed only by classical olfactometry. Classical olfactometry is an expensive and time-consuming method that is not suitable for continuous monitoring as needed by operators of compost facilities. This paper describes a system consisting of a quartz microbalance (QMB) sensor array with an integrated preconcentration unit which is able to measure odorous gases below the odour threshold. The system is developed for use in connection with biofilters in biological waste utilisation (compost facilities). The system is highly sensitive to the main odorous components of waste gas, e.g. limonene, 2-butanone or ethyl acetate. Moreover, the system evinces linear behaviour over a wide range between the odour threshold and some hundred parts per million. It was evaluated both in the laboratory and in field measurements, and it shows very good sensitivity and stability about the tested time in the field measurements (2 weeks).

Real-time reference method in odor recorder under environmental change

This paper presents the electronic record of dynamically changing odors under environmental disturbance using a new recording method for the odor recorder called ‘real-time reference method’. The target odor is recorded as the recipe of several odor components. Once the recipe to represent the target odor is determined, it can be reproduced anytime and anywhere. In the real-time reference method, the target and blended odors are alternately exposed to the sensor array every sampling interval to determine the recipe for reproducing the target odor. Since the two odors are measured in the almost same environmental condition, the influence of dynamically changing environmental disturbance (temperature and humidity disturbances) can be reduced. Moreover, the dynamically changing target odor can be recorded because of the real-time monitoring of the target odors. In this paper, the dynamically changing apple flavors composed of four components were successfully quantified under the temperature and humidity disturbances.

Biofiltration of n-butyric acid for the control of odour

Odour control from pig production facilities is a significant concern due to increased public awareness and the development of more stringent legislation to control production. Although many technologies exist, biofiltration is still the most attractive due to its low maintenance and operating costs. One of the key odour components, n-butyric acid, was selected for a laboratory scale biofilter study. It was examined as a sole carbon substrate in order to investigate the effectiveness of biofiltration in reducing n-butyric acid concentration under different operating conditions using a moist enriched woodchip medium. Three superficial gas velocities; 38.2, 76.4, and 114.6 m h −1 were tested for n-butyric acid concentrations ranging from 0.13 to 3.1 g [ n-butyric acid] m −3 [air]. For superficial gas velocities 38.2, 76.4, and 114.6 m h −1, maximum elimination capacities (100% removal) of 148, 113 and 34.4 g m 3 h −1, respectively, were achieved. Upon investigation of effective bed height, true elimination capacities (100% removal) of 230, 233 and 103 g m −3 h −1, respectively, were achieved at these superficial gas velocities. Averaged pressure drops for superficial gas velocities 38.2, 76.4, and 114.6 m h −1 were 30, 78 and 120 Pa, respectively. It was concluded that biofiltration is a viable technology for the removal of n-butyric acid from waste exhaust air, but near 100% removal efficiency is required due to the low odour detection threshold for this gaseous compound.

USE OF SENSORY EVALUATION FOR MEASURING DEODORIZING EFFECTS OF AN AIR CONDITIONER

ABSTRACTThe application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R2 values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures.

Host location by adult and larval codling moth and the potential for its disruption by the application of kairomones

AbstractMany fruit boring insect pests are difficult to control because of the short time span during which the damaging stage can be targeted before it becomes protected by the host fruit. We investigated the host location behaviour of the codling moth Cydia pomonella (L.) (Lepidoptera: Totricidae) to its apple host (Malus domestica Mill.) in the laboratory, with a view to the potential for extending the susceptible time span by disrupting the host location behaviour of the insects. We found that apple extract arrested neonate larvae. It also both attracted adult female moths and stimulated oviposition. α‐farnesene did not result in these effects to the same degree, suggesting that other components of apple odour are also important in the host location behaviour of this insect. By presenting a source of apple extract alongside an apple host, we examined whether the location of the apple host by larval and adult moths could be disrupted. We found that the application of apple extract could significantly increase the time taken for neonate larvae to locate an apple source. The source of apple extract also competed with the apple host, resulting in fewer eggs being oviposited near the apples. The results suggest that it may be possible to disrupt the host location behaviour of both the neonate larval and adult stage by the application of host kairomones.

Study of recording apple flavor using odor recorder with five components

The odor recorder has been developed using the odor sensing system based on the active sensing method to electronically record odors and reproduce them anytime and anywhere. The recorder developed in this paper has capability of recording the target odor, the mixture of five odor components, using the odor sensor array composed of quartz crystal microbalance sensors. The difference between the sensor response patterns of the recipe and target odors was minimized so that the recipe of the five components for the target odor was determined. In this paper, the method of selecting the most appropriate sensors to record odors was investigated based on the condition number of the sensor array sensitivity matrix. Moreover, the method of determining the parameters of the odor-recording algorithm was studied. As a result, several apple flavors composed of the five components were successfully recorded. Furthermore, the typical apple flavor composed of nine components was approximated using the mixture of the five components. The approximation result by the sensing system was successfully verified by the human sensory test.