Aroma Chemicals Research Articles

Volatile profiles of Cabernet Gernischet wine under rain-shelter cultivation and open-field cultivation using solid-phase micro-extraction–gas chromatography/mass spectrometry

ABSTRACTThe volatile profiles of Vitis vinifera cv. Cabernet Gernischet wines in vintages 2010 and 2011 from rain-shelter cultivation and open-field cultivation were compared and detected by headspace solid phase micro-extraction with gas chromatography-mass spectrometry. The results showed that the number and concentration of volatile compounds quantified in wine were lower under rain-shelter cultivation compared with open-field cultivation. The strength of the fruity, fatty, caramel, and floral aromas of the 2010 vintage wines was lower under rain-shelter cultivation condition, and the compounds contributing to herbaceous aroma series were also lower with rain-shelter cultivation in the 2011 vintage wines. However, the strength of fruity, fatty, caramel, floral, and chemical aromas was higher with rain-shelter cultivation in vintage 2011. The cultivations in the two vintages could be clearly divided into three groups by principal component analysis. The difference between two treatments was significant in vintage 2010, whereas there was no significant difference in vintage 2011. The present work reveals the effects of rain-shelter cultivation on Cabernet Gernischet wine volatile compounds and explains that the technique is helpful in improving the wine quality in some rainy regions.

Skank, or the Queer Fascination with Animalic Notes in Contemporary Niche Perfume

Abstract This article looks at the popularity and overt foregrounding of animalic notes in contemporary niche perfume. Although the natural animal notes are rarely used in contemporary perfume and are usually replaced by synthetic aroma chemicals, the idea of them still intrigues. This article proposes the importance of understanding this desire for the animalic in terms of the psychology of disgust, theories of the abject, and a Western history of scatologic art. It examines some of the spaces and places in which the author encounters perfume and the related affects. The article also proposes that the fascination with animalic fragrance also speaks to the ontology of the sense of smell, a fragile ontology that rests on the unreliable narration of memory. The possibility of developing a queer understanding of this subjectively disrupting fascination with the animalic through the lens of postcontinental queer theories is examined.

Investigation of the aroma of commercial peach (Prunus persica L. Batsch) types by Proton Transfer Reaction–Mass Spectrometry (PTR-MS) and sensory analysis

The aim of this study was to investigate the aroma and sensory profiles of various types of peaches (Prunus persica L. Batsch.). Forty-three commercial cultivars comprising peaches, flat peaches, nectarines, and canning peaches (pavías) were grown over two consecutive harvest years. Fruits were assessed for chemical aroma and sensory profiles. Chemical aroma profile was obtained by proton transfer reaction-mass spectrometry (PTR-MS) and spectral masses were tentatively identified with PTR-Time of Flight-MS (PTR-Tof-MS). Sensory analysis was performed at commercial maturity considering seven aroma/flavor attributes. The four types of peaches showed both distinct chemical aroma and sensory profiles. Flat peaches and canning peaches showed most distinct patterns according to discriminant analysis. The sensory data were related to the volatile compounds by partial least square regression. γ-Hexalactone, γ-octalactone, hotrienol, acetic acid and ethyl acetate correlated positively, and benzeneacetaldehyde, trimethylbenzene and acetaldehyde negatively to the intensities of aroma and ripe fruit sensory scores.

Environmental risk assessment of polycyclic musks HHCB and AHTN in consumer product chemicals in China

An environmental risk assessment (ERA) framework was recently developed for consumer product chemicals in China using a tiered approach, applying an existing Chinese regulatory qualitative method in Tier Zero and, then, utilizing deterministic and probabilistic methods for Tiers One and Two. The exposure assessment methodology in the framework applied conditions specific to China including physical setting, infrastructure, and consumers' habits and practices. Furthermore, two scenarios were identified for quantitatively assessing environmental exposure: (1) Urban with wastewater treatment, and; (2) Rural without wastewater treatment (i.e., direct-discharge of wastewater). Upon a brief discussion on the framework methodology, this paper primarily presented a case study conducted using this new approach for assessing two fragrance chemicals, the polycyclic musks HHCB (Galaxolide, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[gamma]-2-benzopyran) and AHTN (Tonalide, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene). Both HHCB and AHTN are widely used as fragrances in a variety of consumer products in China, and occurrences of both compounds have been reported in wastewater influents, effluents, and sludge, in addition to surface water and sediments across several major metropolitan regions throughout China. This case study illustrated the very conservative nature of Tier Zero, which indicated a high risk potential of the fragrances to receiving water aquatic communities due to the fragrance's non-ready biodegradability and eco-toxicity profiles. However, the higher-tiered assessments (including deterministic and site-specific probabilistic) demonstrated greater environmental realism with the conclusion of HHCB and AHTN posing minimal risk, consistent with local monitoring data as well as a recent similar study conducted in the United States.

Fragrances and work-related asthma–California surveillance data, 1993–2012

ABSTRACTObjective: Fragrance chemicals are used in a large array of products. Workers may be exposed to these chemicals in the workplace directly when used as air fresheners, or indirectly in personal care products used by coworkers or others. This study characterizes work-related asthma (WRA) cases associated with fragrance exposures in California workplaces from 1993 through 2012. Methods: We used the California Work-Related Asthma Prevention Program's surveillance database to identify individuals with physician-diagnosed WRA associated with the use of air fresheners and scented personal care products (perfumes, colognes, etc.). Cases were classified using previously published, standardized surveillance methods. Results: Perfume was the ninth most common exposure identified from 1993 through 2012. A total of 270 WRA cases associated with fragrance exposure were reported during this period, representing 3.8% of all confirmed cases. These 270 cases included 242 associated with perfume or cologne, 32 associated with air freshener, and 4 associated with both. Similar to non-fragrance cases, nearly a quarter of fragrance-associated cases were classified as new-onset asthma. Fragrance-associated cases were significantly more likely to be in office, health, and education jobs than non-fragrance-associated cases. When compared to non-fragrance cases, fragrance cases were significantly more likely to be female (94% vs 62%) and be classified as having work-aggravated asthma (38% vs 20%), yet had similar outcomes compared with cases associated with other exposures. Conclusions: Our surveillance data show that fragrance use in the workplace is associated with WRA. Prevention methods include employee education, enforced fragrance-free policies, well-designed ventilation systems, and good building maintenance.

Genetic variability and correlations of essential oil yield with agro-economic traits in Mentha species and identification of promising cultivars

Mint is an important medicinal and aromatic plant, belongs to ‘Lamiaceae’ family. Its oil contains large number of aroma chemicals like menthol, menthone, isomenthone, menthyl acetate and menthofuran which are used in pharmaceutical, food, flavor, cosmetics and beverage industries. The hydro distilled essential oils of twenty seven cultivars of six Mentha species, viz. Mentha arvensis L., Mentha piperita, Mentha spicata L. Mentha citrata Ehrh., Mentha spicata L.var. virdis and Mentha cardiaca were analyzed and compared by gas chromatography and gas chromatography-mass spectrometry. Agro-morphological and chemical analysis data of all twenty seven varieties of six Mentha species were evaluated. Variation among twenty seven varieties was significant for all economic traits indicating nature and amount of genetic variations. Genetic variation and correlations studies revealed the significant and positive genetic association between number of internodes and thickness of sucker (0.49**), oil content (%) with thickness of sucker (0.49**) and oil yield (unit per urea) with oil content (0.87**). Correlation/s of fresh herb yield with plant height (46*), oil yield with thickness of sucker (0.43*), oil yield with number of internodes (43*), oil content (%) with number of internodes (42*) were also significant and positive. Therefore, these traits may be considered for the selection of high yielding cultivars through correlated response to selection.

Cosmetic components causing contact urticaria: a review and update.

Immediate skin reactions are common in dermatological practice, but may often be overlooked. The main objective of this article is to provide an update of the literature concerning immediate-type reactions or contact urticaria/contact urticaria syndrome caused by cosmetic ingredients in terms of immediate clinical symptoms, positive reactions following open, scratch or, most often, prick testing, and sometimes the detection of specific IgE antibodies. To this end, a selective search in different medical literature databases was performed. This yielded a list of cosmetic ingredients causing immediate reactions, including hair dyes and bleaches, preservatives, fragrance and aroma chemicals, sunscreens, hair glues, plant-derived and animal-derived components, permanent makeup and tattoos, glycolic acid peel, lip plumper, and alcohols. Many of the reported cases, however, lack appropriate controls and detailed investigation. Contact urticaria may occur with or without systemic symptoms, which are sometimes life-threatening.

Diurnal variations in aroma profile of Ocimum basilicum L., O. gratissimum L., O. americanum L., and O. kilimandscharicum Guerke

Ocimum spp. are reputed for their essential oils and aroma chemicals that are highly valued in food and flavor industries. This study was conducted to evaluate the diurnal effect on essential oil yield and composition of four Ocimum species, viz. O. basilicum L., O. gratissimum L., O. americanum L., and O. kilimandscharicum Guerke grown at foothills of Uttarakhand, India. Essential oil content and composition were determined and compared as a function of different harvesting times viz. morning (6.00 a.m.), noon (12.00 p.m.), and evening (6.00 p.m.). O. basilicum, O. americanum, and O. kilimandscharicum (camphor type) gave higher essential oil yield when harvested at noon, while in O. gratissimum, higher oil yield was obtained in the evening, followed by noon and morning harvesting. Oil yield in O. kilimandscharicum (eugenol/methyl chavicol) chemotype was found in the order of: morning > noon > evening. Similar to oil yield, significant qualitative and quantitative differences in essential oil composition of O. gratissimum and O. kilimandscharicum chemotypes were observed, while in O. basilicum chemotypes, little quantitative changes in compositions were found due to different harvesting times of the day. The results obtained could be of economic significance for determining the most favorable time for harvesting.

Fragrance Allergens, Overview with a Focus on Recent Developments and Understanding of Abiotic and Biotic Activation

Fragrances and fragranced formulated products are ubiquitous in society. Contact allergies to fragrance chemicals are among the most common findings when patch-testing patients with suspected allergic contact dermatitis, as well as in studies of contact allergy in the general population. The routine test materials for diagnosing fragrance allergy consist mainly of established mixes of fragrance compounds and natural extracts. The situation is more complex as several fragrance compounds have been shown to be transformed by activation inside or outside the skin via abiotic and/or biotic activation, thus increasing the risk of sensitization. For these fragrance chemicals, the parent compound is often non-allergenic or a very weak allergen, but potent sensitizers will be formed which can cause contact allergy. This review shows a series of fragrance chemicals with well-documented abiotic and/or biotic activation that are indicative and illustrative examples of the general problem. Other important aspects include new technologies such as ethosomes which may enhance both sensitization and elicitation, the effect on sensitization by the mixtures of fragrances found in commercial products and the effect of antioxidants. A contact allergy to fragrances may severely affect quality of life and many patients have multiple allergies which further impact their situation. Further experimental and clinical research is needed to increase the safety for the consumer.

Differential response of genotype × environment on phenology, essential oil yield and quality of natural aroma chemicals of five Ocimum species

We have studies the impact of environmental conditions on phenological traits, biomass and essential oil yields of 15 genotypes of five Ocimum species in two locations in India. Genotypes grown in Lucknow recorded taller plants, greater canopy spread, higher biomass (20.53%) and oil (7.67%) yields. However, genotypes grown in Bangalore recorded higher oil contents and leaf stem ratios. Genotype OCB-9 (Ocimum basilicum) produced maximum biomass 19.85t/ha and O. americanum genotype OCA-12 produced maximum oil yields 55.57l/ha and 61.42l/ha across Lucknow and Bangalore locations. O. tenuiflorum genotypes OCS-2 (48.84l/ha) and OCS-6 (31.02l/ha) produced higher oil yields at Lucknow and Bangalore. Lucknow grown O. gratissimum genotype OCG-14 and O. kilimandscharicum genotype OCK-15 were superior for biomass and oil yields relative to Bangalore grown plants. The present study clearly indicated that O. basilicum genotypes OCB-7, OCB-8 and OCB-11 are promising for specific aroma rich oil production across the locations.

Fragrance plant to be repurposed

ICT Industries has purchased a former International Flavors & Fragrances aroma chemicals facility in Augusta, Ga., and plans to retrofit it to produce specialty polymers and fluorosurfactants. ICT says it expects to hire as many as 100 people over a five-year period following the retrofitting. Founded in 1997, ICT operates two chemical plants and an R&D facility in Cartersville, Ga., that are focused on surface modification products.

Glucosylation of aroma chemicals and hydroxy fatty acids

To explore the utility of glycosyltransferases as novel biocatalysts, we isolated the glycosyltransferase genes CaUGT2 and SbUGTA1 from Catharanthus roseus and Starmerella bombicola, respectively and heterologously expressed them in Escherichia coli. The purified recombinant proteins were assayed with a variety of small molecule substrates. Carvacrol and its phenol isomer thymol are efficiently glucosylated by CaUGT2. The Vmax/Km ratios show that CaUGT2 exhibits the highest specificity towards carvacrol, followed by thymol, geraniol, eugenol, vanillin, menthol, and tyrosol. In contrast, SbUGTA1 accepts ω-hydroxy fatty acids and 1-alkanols as substrates. The Vmax/Km ratios indicate that SbUGTA1 exhibits the highest specificity towards 16-hydroxy palmitic acid, followed by octanol, decanol, and hexadecanol. In biotransformation experiments 23, 88 and 99% of octanol, 16-hydroxy palmitic acid, and decanol, respectively is converted into the corresponding β-glucosides by E. coli cells expressing SbUGTA1 whereas those cells expressing CaUGT2 glucosylate 18, 61, 77 and 97% of applied eugenol, thymol, vanillin, and carvacrol, respectively. To optimize the biotransformation rate, the effects of the concentration of IPTG, glucose, and substrate on the production of glucosides were tested. Taken together, this procedure is a simple operation, environmentally friendly, and is useful for the preparation of glycosides as additives for food and cosmetics.

A Butter Aroma Recombinate Activates Human Class-I Odorant Receptors.

With ∼400 olfactory G protein-coupled receptors (GPCR), humans sensitively perceive ∼230 key aroma compounds as best natural agonists of ∼10000 food volatiles. An understanding of odorant coding, thus, critically depends on the knowledge about interactions of key food aroma chemicals and their mixtures with their cognate receptors. Genetically designed test cell systems enable the screening, deorphaning, and characterization of single odorant receptors (OR). This study shows for the food aroma-specific and quantitative butter aroma recombinate, and its single components, specific in vitro class-I OR activity patterns, as well as the activation of selected OR in a concentration-dependent manner. Recently, chemosensory receptors, especially class-I OR, were demonstrated to be expressed on blood leukocytes, which may encounter foodborne aroma compounds postprandially. This study shows that butter aroma recombinate induced chemotaxis of isolated human neutrophils in a defined gradient, and in a concentration-dependent and pertussis toxin-sensitive manner, suggesting at least a GPCR-mediated activation of blood leukocytes by key food odorants.

Aroma composition of 2-year-old New Zealand Pinot Noir wine and its relationship to sensory characteristics using canonical correlation analysis and addition/omission tests

Background and Aims Relationships between the chemical composition and the sensory perception of red wines are generally poorly understood. In New Zealand, the vineyard area of Pinot Noir has increased markedly and wines from this red cultivar now constitute a significant proportion of total production. The aim of this study was to identify aroma compounds of major sensory significance in New Zealand Pinot Noir wines. Methods and Results The concentration of 34 aroma chemicals in 32 New Zealand Pinot Noir wines was quantified using three separate solid-phase microextraction-GC-MS methods. Relationships between these chemical data and sensory data obtained from the same wines were investigated with canonical correlation analysis. Subsequently, correlation results were validated with addition/omissions tests. Ethyl octanoate was found to increase red cherry aroma, the combination of ethyl octanoate and ethyl decanoate enhanced black cherry aroma, and 2-phenyl ethanol increased violet aroma. Benzaldehyde altered Pinot Noir aroma but its effect on specific attributes was unclear. Conclusions The influence of benzaldehyde, ethyl octanoate and 2-phenyl ethanol on the aroma of Pinot Noir wine was consistent with previous studies conducted on Merlot and Cabernet Sauvignon wines. This indicated that the contribution of these compounds is similar in a range of red wines. Ethyl decanoate appeared to act as an aroma enhancer compound when in combination with ethyl octanoate. Significance of the Study Improved knowledge of key aroma and flavour components and the factors that influence their concentration is required to allow producers to manipulate better sensory characteristics to meet the preferences of specific markets. This study provides new information on important aroma compounds in New Zealand Pinot Noir which can lead to future research on modulating factors.

Metabolic engineering of 2-phenylethanol pathway producing fragrance chemical and reducing lignin in Arabidopsis.

Two 2-phenylethanol biosynthetic pathways were constructed into Arabidopsis ; 2-phenylethanol biosynthesis led to reduced rate of lignin biosynthesis and increased cellulose-to-glucose conversion in the transgenic plants. Lignin is the second most abundant biopolymer on the planet with importance for various agro-industrial activities. The presence of lignin in cell walls, however, impedes biofuel production from lignocellulosic biomass. The phenylpropanoid pathway is responsible for the biosynthesis of lignin and other phenolic metabolites such as 2-phenylethanol. As one of the most used fragrance chemicals, 2-phenylethanol is synthesized in plants from L-phenylalanine which is the first specific intermediate towards lignin biosynthesis. Thus, it is interesting to prove the concept that the phenylpropanoid pathway can be modulated for reduction of lignin as well as production of natural value-added compounds. Here we conferred two 2-phenylethanol biosynthetic pathways constructed from plants and Saccharomyces cerevisiae into Arabidopsis. As anticipated, 2-phenylethanol was accumulated in transgenic plants. Moreover, the transformants showed 12-14% reduction in lignin content and 9-13% increase in cellulose content. Consequently, the glucose yield from cell wall hydrolysis was increased from 37.4% in wild type to 49.9-52.1% in transgenic plants with hot water pretreatment. The transgenic plants had normal development and even enhanced growth relative to the wild type. Our results indicate that the shunt of L-phenylalanine flux to the artificially constructed 2-phenylethanol biosynthetic pathway most likely reduced the rate of lignin biosynthesis in Arabidopsis.

The role of flavor and fragrance chemicals in TRPA1 (transient receptor potential cation channel, member A1) activity associated with allergies.

TRPA1 has been proposed to be associated with diverse sensory allergic reactions, including thermal (cold) nociception, hearing and allergic inflammatory conditions. Some naturally occurring compounds are known to activate TRPA1 by forming a Michael addition product with a cysteine residue of TRPA1 through covalent protein modification and, in consequence, to cause allergic reactions. The anti-allergic property of TRPA1 agonists may be due to the activation and subsequent desensitization of TRPA1 expressed in sensory neurons. In this review, naturally occurring TRPA1 antagonists, such as camphor, 1,8-cineole, menthol, borneol, fenchyl alcohol and 2-methylisoborneol, and TRPA1 agonists, including thymol, carvacrol, 1’S-1’- acetoxychavicol acetate, cinnamaldehyde, α-n-hexyl cinnamic aldehyde and thymoquinone as well as isothiocyanates and sulfides are discussed.

Air-oxidized linalyl acetate - an emerging fragrance allergen?

Linalyl acetate is a fragrance chemical that is prone to autoxidation. Exposure to linalyl acetate occurs through cosmetic products and essential oils, but is difficult to assess, as linalyl acetate is not labelled in the EU. To investigate the frequencies of contact allergy to oxidized linalyl acetate among dermatitis patients, and to investigate the autoxidation of linalyl acetate in terms of hydroperoxide formation and sensitization potency. Hydroperoxide formation in air-exposed linalyl acetate was determined with high-performance liquid chromatography. The sensitization potencies of hydroperoxides were determined with the local lymph node assay. One thousand seven hundred and seventeen patients were patch tested with oxidized linalyl acetate at 6.0% in petrolatum. Of the patients, 2.2% showed positive reactions to oxidized linalyl acetate. Forty-three per cent of the positive patients also had positive patch test reactions to other fragrance markers. Linalyl acetate hydroperoxides were detected early in the autoxidation process, and accumulated to a concentration of 37% after 42 weeks of air exposure. The linalyl acetate hydroperoxides were classified as moderate sensitizers. The frequency of positive reactions to oxidized linalyl acetate is comparable to that of previously studied oxidized fragrance terpenes. Oxidized linalyl acetate could thus be a common fragrance contact allergen.

Enhanced acetate ester production of Chinese liquor yeast by overexpressing ATF1 through precise and seamless insertion of PGK1 promoter.

As the most important group in the flavor profiles of Chinese liquor, ester aroma chemicals are responsible for the highly desired fruity odors. Alcohol acetyltransferase (AATase), which is mainly encoded by ATF1, is one of the most important enzymes for acetate ester synthesis in Saccharomyces cerevisiae. In this study, we overexpressed ATF1 in Chinese liquor yeast through precise and seamless insertion of PGK1 promoter (PGK1p) via a novel fusion PCR-mediated strategy. After two-step integration, PGK1p was embedded in the 5'-terminal of ATF1 exactly without introduction of any extraneous DNA sequence. In the liquid fermentation of corn hydrolysate, both mRNA level and AATase activity of ATF1 in mutant were pronounced higher than the parental strain. Meanwhile, productivity of ethyl acetate increased from 25.04 to 78.76mg/l. The self-cloning strain without any heterologous sequences residual in its genome would contribute to further commercialization of favorable organoleptic characteristics in Chinese liquor.

Correlation between experimental human and murine skin sensitization induction thresholds

Quantitative risk assessment for skin sensitization is directed towards the determination of levels of exposure to known sensitizing substances that will avoid the induction of contact allergy in humans. A key component of this work is the predictive identification of relative skin sensitizing potency, achieved normally by the measurement of the threshold (the “EC3” value) in the local lymph node assay (LLNA). In an extended series of studies, the accuracy of this murine induction threshold as the predictor of the absence of a sensitizing effect has been verified by conduct of a human repeated insult patch test (HRIPT). Murine and human thresholds for a diverse set of 57 fragrance chemicals spanning approximately four orders of magnitude variation in potency have been compared. The results confirm that there is a useful correlation, with the LLNA EC3 value helping particularly to identify stronger sensitizers. Good correlation (with half an order of magnitude) was seen with three-quarters of the dataset. The analysis also helps to identify potential outlier types of (fragrance) chemistry, exemplified by hexyl and benzyl salicylates (an over-prediction) and trans-2-hexenal (an under-prediction).

Potential applications of glucosyltransferases in terpene glucoside production: impacts on the use of aroma and fragrance.

The detection of glucoconjugated forms of monoterpene alcohols in rose petals in the late 1960s opened the new field of nonvolatile aroma precursors in flavor research. It is now well established that odorless glycosides represent a significant pool of aroma precursors in plants where they act as preformed but inactivated defense or attractive chemicals. Technical improvements in the separation and identification of plant secondary metabolites have provided a multitude of chemical structures, but functional characterization of glycosyltransferases that catalyze their formation lags behind. As technical efforts and costs for DNA sequencing dramatically dropped during the last decade, the number of plant genome sequences increased significantly, thus providing opportunities to functionally characterize the glycosyltransferase gene families in plants. These studies yielded the first glycosyltransferase genes that encode efficient biocatalysts for the production of monoterpene glucosides. They have applications in the food, feed, chemical, cosmetic, and pharmaceutical industries as slow release aroma chemicals.