Fragrance Mixtures Research Articles

Function of environment-derived male perfumes in orchid bees

Perfume making in male orchid bees is a unique behavior that has given rise to an entire pollination syndrome in the neotropics.1,2 Male orchid bees concoct and store species-specific perfume mixtures in specialized hind-leg pockets3 using volatiles acquired from multiple environmental sources, including orchid flowers.4,5 However, the function and the ultimate causes of this behavior have remained elusive.2,6 Although previous observations suggested that male perfumes serve as chemical signals, the attractiveness for females has not be shown.7,8 Here, we demonstrate that the possession of perfume increases male mating success and paternity in Euglossa dilemma, a species of orchid bees recently naturalized in Florida. We supplemented males reared from trap-nests with perfume loads harvested from wild conspecifics. In dual-choice experiments, males supplemented with perfumes mated with more females, and sired more offspring, than untreated, equal-aged, control males. Although perfume supplementation had little effect on the intensity of male courtship display, it changed the dynamics of male-male interactions. Our results demonstrate that male-acquired perfumes are sexual signals that stimulate females for mating and suggest that sexual selection is key in shaping the evolution of perfume communication in orchid bees.

Patchouli Oil Innovation in Making Peel-Off Masks to Inhibit Acne Bacteria

One of the plants that produce essential oils is patchouli. Patchouli contains patchouli oil which has many benefits, including as an antibacterial, antioxidant, and can be used in perfume mixtures. In this study, patchouli oil was used in the manufacture of peel-off masks. This study aims to test the ability of peel off masks as antibacterial which can inhibit acne-causing bacteria. The results of this study are peel-off mask can inhibit the growth of acne-causing bacteria, namely Staphylococcus aureus. The clear zone formed is 11.8 mm, which indicates that the peel-off mask has a strong inhibitory power to inhibit the growth of acne-causing bacteria. Peel-off masks have a thick texture, white colour, and are easy to peel off when dry. The results of this study provide information for the development of Peel-Off masks as antibacterial, especially for the cosmetic and health fields.

Study of the Thermodynamic Equilibrium of Fragrance Mixtures, Limonene, Linalool and Geraniol, using the Unifac and Cosmo-Sac Models and the Estimation of their Combined Properties in Binary, Ternary and Quaternary Mixtures

Study of the Thermodynamic Equilibrium of Fragrance Mixtures, Limonene, Linalool and Geraniol, using the Unifac and Cosmo-Sac Models and the Estimation of their Combined Properties in Binary, Ternary and Quaternary Mixtures

Effects of a Multicomponent Perfume Accord and Dilution on the Formation of ST2S/CAPB Mixed-Surfactant Microemulsions.

Perfume mixtures contain perfume raw materials (PRMs) with varying structures and hydrophobicities, which influence PRM localization within a surfactant-based formulation and thereby affect the phase behavior. In rinse-off products, the addition of water can further affect the phase behavior. In this study, a mixture of 12 PRMs was used as the oil phase in an aqueous system consisting of sodium trideceth-2 sulfate as a primary surfactant, cocamidopropyl betaine as a cosurfactant, and dipropylene glycol as a cosolvent. A series of phase diagrams were constructed with increasing water content, simulating the use conditions for rinse-off products, to determine how the phase boundaries shift with dilution. Using these phase diagrams, the compositions of interest in the micelle without perfume, micelle with perfume, microemulsion, and micelle-microemulsion transition regions were identified at each dilution level. The structural changes were probed through combined small-angle neutron scattering (SANS) and cryo-transmission electron microscopy analyses. The SANS results showed that ellipsoidal micelles were maintained as the perfume content and the dilution level increased. With ≥50 wt % water, increasing the perfume content increased the micelle volume. Interestingly, a higher rate of volume increase was observed at ≥70 wt % water. Notably, the volumes of the micelles with and without perfume increased steadily with dilution, whereas the volumes of the assemblies in the transition region and the microemulsion region increased more rapidly once diluted to 70 and 80 wt % water, respectively.

Structural alterations of branched versus linear mixed-surfactant micellar systems with the addition of a complex perfume mixture and dipropylene glycol as cosolvent.

Personal care products commonly contain perfume mixtures, consisting of numerous perfume raw materials (PRMs), and cosolvents. The lipophilicity and structure of an individual PRM is known to affect its localization within the surfactant self-assembly as well as the micellar geometry. However, because multiple PRMs are used in formulations, significant intermolecular interactions between the PRMs and between the PRMs and the surfactant tail may also influence the location of the PRMs and their effects on the self-assembly. Herein, two anionic/zwitterionic mixed-surfactant systems (sodium trideceth-2 sulfate (ST2S)/cocamidopropyl betaine (CAPB) and sodium laureth-3 sulfate/CAPB) were formulated with a cosolvent (dipropylene glycol (DPG)) and 12 PRMs of varying structures and lipophilicities. This 12 PRM accord is simpler than a fully formulated perfume but more complex than a single perfume molecule. The geometric variations in the self-assemblies were evaluated using small-angle neutron scattering, perfume head space concentrations were determined using gas chromatography-mass spectrometry, and perfume localization was identified using NMR spectroscopy. The addition of the perfume accord caused enlargement of the micelles in both surfactant systems, with a greater change observed for ST2S/CAPB formulations. Furthermore, the addition of DPG to ST2S/CAPB resulted in micelle shrinkage. The micelle geometries and PRM localization in the micelles were affected by the degree of branching in the surfactant tail.

Modeled Emission of Hydroxyl and Ozone Reactivity from Evaporation of Fragrance Mixtures.

Volatile chemical products (VCPs) account for increasing fractions of organic carbon emitted to the atmosphere, particularly in urban areas. Fragrances are potentially reactive components that are added to many VCPs. To better constrain these emissions, 11 commercially available liquid fragrance mixtures were characterized for their composition and their evaporation modeled. Emissions of mass, hydroxyl reactivity, and ozone reactivity were estimated by modeling under four different scenarios. Fragrance compounds were generally less than one-half the mass of fragrance mixtures, with the balance comprised of solvents and plasticizers and unresolved mass thought to be dominated by plasticizers. The results showed that terpenes and terpenoids account for nearly all of the emitted mass and reactivity while only comprising ∼10% w/w on average of the liquid fragrance mixtures. Most of the reactivity is emitted within hours, with ozone reactivity evolving more rapidly than OH reactivity and comprised almost entirely of terpenes. Limonene, a common fragrance constituent, dominates the reactivity of emitted carbon. Generally, 20-40% of the potential hydroxyl reactivity contained in the fragrance mixture does not evaporate on time scales sufficient to have an impact on local or regional air quality.

Unraveling the Olfactory Biases of Male Euglossine Bees: Species-Specific Antennal Responses and Their Evolutionary Significance for Perfume Flowers

Male euglossine bees exhibit unique adaptations for the acquisition and accumulation of chemical compounds from “perfume flowers” and other sources. During courtship display, male bees expose perfume mixtures, presumably to convey species-specific recognition and/or mate choice signals to females. Because olfaction regulates both signal production (in males) and signal detection (in females) in this communication system, strong selective pressures are expected to act on the olfactory system, which could lead to sensory specialization in favor of an increased sensitivity to specific chemical compounds. The floral scents of euglossine-pollinated plants are hypothesized to have evolved in response to the preexisting sensory biases of their male euglossine bee pollinators. However, this has never been investigated at the peripheral olfactory circuitry of distinct pollinating genera. Here, we present a comparative analysis using electroantennography (EAG) of males across the phylogeny of 29 euglossine bee species, among them Euglossa and Eulaema species. First, we tested whether antennal responses differ among different euglossine genera, subgenera and species. Secondly, we conducted a comparative phylogenetic analysis to investigate the macroevolutionary patterns of antennal responses across the euglossine bee phylogeny. We found that antennal response profiles are very unique on the species level and differ on the subgenus and the genus level. The differences can be explained by chemical compounds typically found in the floral scent bouquets of perfume flowers and specific compounds of species either pollinated by Euglossa (e.g., ipsdienol) or Eulaema bees (e.g., (−)-(E)-carvone epoxide). Also, we detected a phylogenetic signal in mean antennal responses and found that especially at the species level of our simulation the overall antennal responses exhibit greater disparity relative to a null model of pure Brownian-motion across the phylogeny. Altogether, our results suggest that (1) euglossine bee species exhibit species-specific antennal responses that differ among euglossine genera and subgenera, (2) antennal responses diverge early after speciation events, and (3) scent composition of perfume flowers evolved in response to pollinator-mediated selection imposed by preexisting sensory biases in euglossine bees.

Perfume and Flavor Engineering: A Chemical Engineering Perspective.

In the last two decades, scientific methodologies for the prediction of the design, performance and classification of fragrance mixtures have been developed at the Laboratory of Separation and Reaction Engineering. This review intends to give an overview of such developments. It all started with the question: what do we smell? The Perfumery Ternary Diagram enables us to determine the dominant odor for each perfume composition. Evaporation and 1D diffusion model is analyzed based on vapor-liquid equilibrium and Fick’s law for diffusion giving access to perfume performance parameters. The effect of matrix and skin is addressed and the trail of perfumes analyzed. Classification of perfumes with the perfumery radar is discussed. The methodology is extended to flavor and taste engineering. Finally, future research directions are suggested.

Measurement and evaluation of gaseous and particulate emissions from burning scented and unscented candles

It has been known for a long time that incomplete combustion processes produce by-products that are harmful to human health. Particularly high concentrations of such by-products can arise in indoor environments when operating open flames without venting. The emission behavior of many combustion sources, including candles, has already been examined in detail. However, to date there are no studies in which the chemical composition of the candles is known exactly or where the candles were specifically manufactured for comparative measurements. In this respect, the study presented here, which was designed in collaboration with candle manufacturers and fragrance houses, demonstrates new insights into the emissions of burning candles depending on their composition.All investigations were carried out under controlled climatic conditions in an 8 m3 stainless steel chamber. Combinations of four different fuels (waxes) and five different fragrances in addition to one set of unscented control candles were examined. This resulted in 24 experiments, 20 with scented candles and four with unscented candles. The typical combustion gases carbon monoxide, carbon dioxide and NOx, organic compounds, such as formaldehyde, benzene, and polycyclic aromatic hydrocarbons, PM2.5 and ultrafine particles were monitored in the chamber air and the emission rates were determined. The data were statistically evaluated using parametric and non-parametric methods as well as hierarchical cluster analysis. Exposure scenarios typical for indoor environments were calculated from the emission rates and the results were compared with indoor guidance and reference values.As expected, a multitude of gaseous and particulate emissions were detected. These were typical combustion products as well as evaporated constituents of the fragrance mixtures. In most cases, the calculated indoor concentrations were well below the respective guidance and reference values. The exceptions observed in some cases for nitrogen dioxide, acrolein and benzo[a]pyrene are discussed critically.

Encapsulation of Fragrance in Aqueous Emulsions by Delaminated Synthetic Hectorite.

Fragrance emulsions are used in many applications in daily life. Since a lot of fragrances are quite volatile substances, their release rate from emulsions is a crucial factor. Since in most cases a mixture of fragrances is applied, the olfactory impression might change over time if the release rates of individual components differ significantly. For such applications, encapsulation with barrier materials is sought to retard release in an unselective manner. Stable fragrance-in-water emulsions were made by applying a synthetic hectorite as Pickering emulsifier which was fixed as a multilayer stack at the oil-water interface by adding poly(ethylene imine). The release of different fragrance molecules (eucalyptol, limonene, α-pinene, and ethyl-2-methylbutyrate) from these emulsions was studied as the ratio between hectorite and poly(ethylene imine) was varied. While the release rates of all fragrances were retarded by the hybrid capsule acting as a nonselective barrier, the relative release was determined by the solubility of individual fragrances in the capsule material. Fragrance release could be further reduced by additional chemical cross-linking of poly(ethylene imine).

Polystyrene‐Based 2‐Oxoacetates for the Light‐Induced Release of Fragrances Under Realistic Application Conditions

AbstractLight‐sensitive 2‐oxoacetate‐derived polystyrene copolymers are investigated for the controlled release of fragrances. The stimuli‐responsive delivery systems are efficiently prepared in a two‐step reaction sequence. Simultaneous Friedel–Crafts acylation and cationic polymerization of styrene give access to 2‐oxoacetate‐derived polystyrenes in one step; the fragrance to be released is then introduced by organotin‐catalyzed transesterification in a second step. The performance of the copolymer conjugates releasing either individual fragrance raw materials or a fragrance mixture is evaluated by dynamic headspace analysis in the presence of surfactants on different substrates and compared with their non‐polymeric analogues. Direct and indirect deposition of the delivery systems onto cotton in a fabric softening application show that differences in performance are correlated with the amount of surface deposition. In the present study, the copolymer that releases a fragrance mixture performs better than the copolymers that release the corresponding fragrances individually and better than the respective non‐polymeric profragrances.

Characterisation of complex perfume and essential oil blends using multivariate curve resolution-alternating least squares algorithms on average mass spectrum from GC-MS

Quality control of essential oil blends and the discovery of potential adulterations and product fraud is a significant challenge within the natural oil and perfume industry. In this research, total chromatogram average mass spectra (TCAMS), created from the GC-MS three-way raw data, were employed for the characterisation of complex samples of perfumes and essential oil blends. A multivariate approach for curve resolution was used to resolve the TCAMS of pure essential oils within such perfume and essential oil blends. Resolved TCAMS, in combination with unsupervised pattern recognition approaches revealed the distillation grade and origin of used ylang-ylang oils in perfume mixtures. TCAMS resolved from the essential oil blends were used with a supervised machine learning classification model to identify oils, used in creating the blends. Quantification was performed using a multivariate curve resolution approach, resulting in relative errors of prediction lower than 17.84% with root mean square errors of prediction smaller than 3.43.

Predicting VLE and Odor Intensity of Mixtures Containing Fragrances with COSMO-SAC

In this study, vapor–liquid equilibria (VLE) of binary, ternary, and quaternary systems containing fragrances were predicted using COSMO-SAC. A model variant including multiple energies for the description of different hydrogen bonds (alcohol–alcohol, alcohol–ketone, alcohol–ether) was used. Based on equilibrium vapor compositions, odor intensity, and character of fragrance mixtures were calculated using Stevens’ power law for olfaction intensity scale and stronger component model for quality perception. Very good agreement between predicted and measured data was obtained with COSMO-SAC. Model predictions were similar to UNIFAC outcomes, but without using any binary interaction parameter. Based on these results, this study also indicates the possibility to use COSMO-SAC to predict VLE in mixtures that contain fragrances with missing UNIFAC parameters.

Sexual dimorphism in visual and olfactory brain centers in the perfume-collecting orchid bee Euglossa dilemma (Hymenoptera, Apidae).

Insect mating behavior is controlled by a diverse array of sex‐specific traits and strategies that evolved to maximize mating success. Orchid bees exhibit a unique suite of perfume‐mediated mating behaviors. Male bees collect volatile compounds from their environment to concoct species‐specific perfume mixtures that are presumably used to attract conspecific females. Despite a growing understanding of the ecology and evolution of chemical signaling in orchid bees, many aspects of the functional adaptations involved, in particular regarding sensory systems, remain unknown. Here we investigated male and female brain morphology in the common orchid bee Euglossa dilemma Bembé & Eltz. Males exhibited increased relative volumes of the Medulla, a visual brain region, which correlated with larger compound eye size (area). While the overall volume of olfactory brain regions was similar between sexes, the antennal lobes exhibited several sex‐specific structures including one male‐specific macroglomerulus. These findings reveal sexual dimorphism in both the visual and the olfactory system of orchid bees. It highlights the tendency of an increased investment in the male visual system similar to that observed in other bee lineages, and suggests that visual input may play a more important role in orchid bee male mating behavior than previously thought. Furthermore, our results suggest that the evolution of perfume communication in orchid bees did not involve drastic changes in olfactory brain morphology compared to other bee lineages.

Predicting Vapor-Phase Concentrations for the Assessment of the Odor Perception of Fragrance Chemicals Diluted in Mineral Oil

In this study, the Henry’s law methodology is applied to predict the release of odorants present in single and multicomponent fragrance mixtures diluted in mineral oil, a simplified matrix used in cosmetic products. To attain this goal, the experimental Henry’s law constant (H) of each odorant in each studied fragrance system (containing one, two, three, or four odorants) was first evaluated by plotting their liquid phase and experimental vapor phase concentrations assessed by headspace gas chromatography. From that point, the H value of each odorant in the multicomponent fragrance system was predicted from its corresponding Hexp in the single fragrance component system. The theoretical vapor-phase concentrations were also calculated using the activity coefficients for vapor–liquid equilibria by applying the thermodynamic UNIFAC model. The odor intensity and character of the studied fragrance systems were assessed through the Stevens’s power law and Strongest Component models (psychophysical models). This study confirmed that the headspace concentrations and odor intensity of each odorant present in a multicomponent fragrance mixture dissolved in mineral oil can be efficiently predicted from its corresponding H determined when present alone in the simplified matrix, for low concentrations. Also, comparing both methodologies, UNIFAC and Henry’s law, it was concluded that Henry’s law is a better predictive model for the vapor–liquid equilibria, showing lower deviations from the experimental data. Therefore, the proposed predictive mathematical model can be attractive for the assessment of sensory quality of multicomponent fragrance systems in early formulation stages.

Method translation and full metadata transfer from thermal to differential flow modulated comprehensive two dimensional gas chromatography: Profiling of suspected fragrance allergens

The possibility to transfer methods from thermal to differential-flow modulated comprehensive two-dimensional gas chromatographic (GC×GC) platforms is of high interest to improve GC×GC flexibility and increase the compatibility of results from different platforms. The principles of method translation are here applied to an original method, developed for a loop-type thermal modulated GC×GC–MS/FID system, suitable for quali-quantitative screening of suspected fragrance allergens. The analysis conditions were translated to a reverse-injection differential flow modulated platform (GC×2GC–MS/FID) with a dual-parallel secondary column and dual detection.The experimental results, for a model mixture of suspected volatile allergens and for raw fragrance mixtures of different composition, confirmed the feasibility of translating methods by preserving 1D elution order, as well as the relative alignment of resulting 2D peak patterns. A correct translation produced several benefits including an effective transfer of metadata (compound names, MS fragmentation pattern, response factors) by automatic template transformation and matching from the original/reference method to its translated counterpart. The correct translation provided: (a) 2D pattern repeatability, (b) MS fragmentation pattern reliability for identity confirmation, and (c) comparable response factors and quantitation accuracy within a concentration range of three orders of magnitude. The adoption of a narrow bore (i.e. 0.1mm dc) first-dimension column to operate under close-to-optimal conditions with the differential-flow modulation GC×GC platform was also advantageous in halving the total analysis under the translated conditions.

Manipulating perfume delivery to the interface using polymer–surfactant interactions

Enhanced delivery of perfumes to interfaces is an important element of their effectiveness in a range of home and personal care products. The role of polyelectrolyte–surfactant mixtures to promote perfume adsorption at interfaces is explored here. Neutron reflectivity, NR, was used to quantify the adsorption of the model perfumes phenylethanol, PE, and linalool, LL, at the air–water interface in the presence of the anionic surfactant sodium dodecylsulfate, SDS, and the cationic polyelectrolytes, poly(dimethyldiallyl ammonium chloride), polydmdaac, and poly(ethyleneimine), PEI. The strong SDS–polydmdaac interaction dominates the surface adsorption in SDS–polymer–perfume (PE, LL) mixtures, such that the PE and LL adsorption is greatly suppressed. For PEI–SDS–perfume mixtures the PEI–LL interaction competes with the SDS–PEI interaction at all pH at the surface and significant LL adsorption occurs, whereas for PE the PEI–SDS interaction dominates and the PE adsorption is greatly reduced. The use of the strong surface polyelectrolyte–ionic surfactant interaction to manipulate perfume adsorption at the air–water interface has been demonstrated. In particular the results show how the competition between polyelectrolyte, surfactant and perfume interactions at the surface and in solution affect the partitioning of perfumes to the surface

Modeling Fragrance Components Release from a Simplified Matrix Used in Toiletries and Household Products

A new methodology based on Henry’s law is proposed for modeling the release of fragrances from a simplified matrix commonly used in consumer products’ formulations. For that purpose, different mixtures were formulated containing one, two, three, or four fragrance ingredients diluted in dipropylene glycol (simplified matrix). Headspace concentrations were measured to estimate Henry’s constants (H) for each fragrance component in all mixtures. The individual Henry’s constants for multicomponent fragrance mixtures were also predicted from the ones measured for each single compound diluted in the matrix. Furthermore, we used a model that combines the UNIFAC group-contribution method with the modified Raoult’s law and the psychophysicals Stevens’ power law and strongest component model to predict the perceived odor intensity and character, respectively. Results showed a strong linear relationship between experimental H for single fragrances and experimental H for binary (r2 = 0.998), ternary (r2 = 0.997), and ...

Determination of characteristic lengths and times for wormlike micelle solutions from rheology using a mesoscopic simulation method

We apply our recently developed mesoscopic simulation method for entangled wormlike micelle (WLM) solutions to extract multiple micellar characteristic lengths and time constants: i.e., average micelle length, breakage rate, and entanglement and persistence lengths, from linear rheological measurements on commercial surfactant solutions, one containing sodium lauryl one ether sulfate (SLE1S), and the other containing both SLE1S and cocamidopropyl betaine, as well as a perfume mixture, in both cases with a sample salt (NaCl) added. Measurements include both mechanical rheometry and diffusing wave spectroscopy, the latter providing the high-frequency data needed to determine micelle persistence length accurately. By fitting the experimental data ( G′ and G″) across the entire frequency range through our iteration procedure, the method is of practical use in predicting micellar parameters, which are difficult to obtain from other theoretical or experimental methods. The dependence of micellar parameters on a...

CHEMICAL CATALYTIC AND BIOCATALYTIC PROCESS OF CLOVE OIL DERIVATIVES REVIEW

In 2011, Indonesian clove oil supply reached about 75 % (4,500 of 6,000 tons) of the world market. Utilization of clove oil and clove oil derivatives in aromatic chemical industry primarily as a mixture or additive of fragrances in the daily consumed product, such as perfumes, skin care products, deodorant, soap, shampoo, detergent, besides it is also used as an ingredient in the production of synthetic vanilla. The content of eugenol as the main compound in the essential oil in the clove flower, flower stalk and leaf have a range of 90-95 %, 83-95 % and 82-87 % respectively. The compounds content in clove oil is divided into two categories, phenolics (eugenol) and non-phenolic (beta-caryophyllene) that can be derivatized with various chemocatalytic and biocatalytic processes. Separation of the compounds in clove oil can be conducted by adding NaOH with repeated distillation. This process produces two layers product, the first layer contains eugenol and NaOH, while the second layer contains beta-caryophyllene. Derivatization of eugenol are conducted to produce various products such as vanilla, eugenyl ether, methyl ether eugenyl, eugenyl ethyl ether, eugenyl acetate, eugenyl cinnamate, dimmer eugenol and eugenyl benzoate, whereas derivatization of beta-caryophyllene are conducted to produce products such as caryophyllene oxide, kobusan, glycols, alcohols caryophyllene, β-caryolanylformate and kovanilformate, klovanildiformate, caryophyllene ketol. Biocatalysis or biotransformation can be defined as the use of biological systems (intact cells, cell extracts or isolated enzymes) to catalyze the conversion of a compound into another. Besides the common chemocatalysis system for derivatization of clove oil and clove oil compound such as eugenol into other compounds some biocatalysis systems were also described in this paper.Keywords: Clove oil, eugenol, beta-caryophyllene, derivatization, chemical catalysis, biocatalysis