Volatile Organic Compounds Fingerprints Research Articles

Analysis of unique volatile organic compounds in “Mianhua” made from wheat planted in arid alkaline land

Hebei Province's Huanghua “Mianhua” is a province intangible cultural property made from arid alkaline wheat (AAW). This study aims to assess how different soil conditions affect the volatile organic compounds (VOCs) of “Mianhua” and identify distinct VOCs for land type discrimination. These findings will guide future research on AAW products, enhancing their processing and utilization. 51 VOCs in “Mianhua” from wheat samples grown in arid alkaline land and general land in Huanghua were analyzed by Gas Chromatography-Ion Mobility Spectrometry (GC-IMS). The result of ANOVA, VOC fingerprint, T test, and OPLS-DA revealed VOCs differences based on planting environments. According to multivariate variance contribution rate analysis, most VOCs were more affected by the variety. Land type significantly influenced (E)-2-heptenal (75.3%), Butanol (60.6%), Propyl acetate (60.0%), ethyl pentanoate (45.5%), and ethyl acetate (44.4%). LDA progressively identified Butanol as the characteristic VOC to distinguish “Mianhua” between it made from AAW and general wheat (GW), with a classification accuracy of 75%.

GC-IMS and multivariate analyses of volatile organic components in different Chinese breeds of chickens

This study examined the difference in volatile flavor characteristics among four different local breeds of chicken by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) combined with multivariate analysis. In total, 65 volatile organic compounds (VOCs) were identified (17 aldehydes, 12 alcohols, 7 ketones, 5 esters, 2 acids, and 22 unidentified, i.e., 26.15% aldehydes, 18.46% alcohols, 10.77% ketones, 7.69% esters, 3.08% acids, and 33.84% unidentified), of which 43 were annotated. The chicken meats from the four breeds exhibited good separation in topographic plots, VOC fingerprinting, and multivariate analysis. Meanwhile, 20 different volatile components, with variable importance in projection value > 1, were selected as potential markers to distinguish different breeds of chicken by partial least squares discriminant analysis (PLS-DA). These findings provide insights into the flavor traits of chicken meat. Also, HS-GC-IMS combined with multivariate analysis can be a convenient and powerful method for characterizing different meats.

Aromatic Characterization of Graševina Wines from Slavonia and Podunavlje Sub-Regions

This study investigated the chemical aromatic profiles of 60 volatile organic compounds (VOCs), including 21 terpenes, 6 norisoprenoids, 6 volatile phenols, 4 C-6 alcohols, and 23 esters, in Graševina wines originating from Slavonia and Podunavlje sub-regions (Croatia). Headspace solid-phase microextraction gas chromatography coupled with mass spectrometric detection (HS-SPME-GCMS) was used to assess 60 VOCs, and a novel HS-SPME-GCMS method for the determination of terpenes and norisoprenoids was developed and validated. Statistical analysis found no significant differences between VOCs present in Graševina wines and others wines (Chardonnay and Pinot gris); nonetheless, comparison of VOC fingerprints between different wines from the same producer showed that four terpenes (α-terpinene, γ-terpinene, 1,4-cineol, and 4-terpineol) were present in higher amounts in Graševina wines when compared to other wines. By exclusively examining VOCs within Graševina wines through the utilization of a heatmap and hierarchical clustering, a distinct visualization of samples and VOCs emerged, highlighting the vintage effect. Simultaneously, a partial least squares discriminant analysis model was developed with a confidence interval of 95%, demonstrating a noticeable distinction between samples originating from the western and eastern regions. Furthermore, by employing the heatmap using only VOCs from the terpene and norisoprenoidic groups, a clear separation of samples into two groups was observed based on geographical origin; namely, higher concentrations of norisoprenoids and terpenes were observed in the Slavonia sub-region. These results suggest that terpenes and norisoprenoids to a lower extent may be valuable aromatic markers for the regional typicality of Graševina wines.

Uncovering the Counterfeit: A study of whiskey authenticity through volatile organic compound fingerprinting, aroma and color sensory analysis

This study presents a method employing gas chromatography coupled with mass spectrometry and headspace solid-phase microextraction (HS-SPME-GC–MS), supplemented with chemometrics (Soft independent modelling of class analogies - SIMCA), to analyze volatile organic compound (VOCs) profiles in suspect whiskey samples. Furthermore, a sensory analysis of aroma and color was conducted with a panel of 52 non-trained volunteers to evaluate their ability to discriminate and preference for counterfeit whiskeys. The HS-SPME-GC–MS method successfully distinguished 41 seized samples from authentic beverages. Interestingly, sensory analysis revealed that panelists could differentiate between counterfeit and authentic samples with a reference standard but did not consistently show a preference for aroma. In some cases, there was even a preference for the color of counterfeit whiskeys. The findings suggest that sensorial tests alone may not effectively distinguish counterfeit from authentic whiskeys, especially for non-expert consumers, highlighting the need for analytical instrumentation methods in fraud detection.

Traceability tagging of volatile organic compound sources and their contributions to ozone formation in Suzhou using vehicle-based portable single-photon ionization mass spectrometry

BackgroundIn recent decades, there has been an increasing global preoccupation with atmospheric volatile organic compounds (VOCs). Given the significant impact of VOCs as pollutants and essential precursors of ozone (O3) in urban and industrial areas, it is imperative to identify and quantify the sources of their emissions to facilitate the development and implementation of effective environmental control strategies.MethodsA mobile laboratory vehicle equipped with a single-photon ionization–time-of-flight mass spectrometer (SPI–TOFMS) and a navigation system was employed to establish the traceability of VOCs that contribute to the formation of ozone in Suzhou Industrial Park. The method exhibited a favorable detection limit of 0.090 ppbv, accompanied by a mass resolution of 1500 for the instrument and a correlation coefficient ≥ 0.990. A positive matrix factorization (PMF) model was utilized to determine the source appointment of the VOCs.ResultsThe study tentatively traced and identified the VOCs emissions source and their contribution to ozone formation in Suzhou. Using the PMF model, the sources of VOCs were profiled: three primary sources of VOCs were identified, namely, vehicular emissions, an industrial solvent, and biofuel combustion. Alkanes groups were found to be the most abundant VOCs species, accounting for 60% of the total VOCs, followed by aromatics and alkenes. Maximum incremental reactivity (MIR) quantifies the impact of photochemical reaction mechanism on the potential ozone formation.ConclusionsThe findings of this study complement existing knowledge on the pollution status of atmospheric VOCs and highlight the correlation with ozone formation potential in Suzhou. The aforementioned sources were identified as the primary factors responsible for the pollution in Suzhou. The successful implementation of SPI–TOFMS has demonstrated a promising methodology that is well-suited for the real-time and online monitoring of VOCs in the atmosphere. In addition, a library for identifying VOC fingerprints from the same plant was established. This library serves as a comprehensive resource for establishing on-site VOC traceability, estimating source apportionment, and evaluating their impact on ozone formation.

Explorative study for the rapid detection of Fritillaria using gas chromatography-ion mobility spectrometry.

Fritillaria is a well-known health-promoting food, but it has many varieties and its market circulation is chaotic. In order to explore the differences in volatile organic compounds (VOCs) among different varieties of Fritillaria and quickly and accurately determine the variety of Fritillaria, this study selected six varieties of Fritillaria and identified and analyzed their volatile components using gas chromatography-ion mobility spectrometry (GC-IMS), establishing the characteristic fingerprints of VOCs in Fritillaria. In all samples, a total of 76 peaks were detected and 67 VOCs were identified. It was found that the composition of VOCs in different varieties of Fritillaria was similar, but the content was different. Combined with chemometric analysis, the differences between VOCs were clearly shown after principal component analysis, cluster analysis, and partial least-squares discriminant analysis. This may provide theoretical guidance for the identification and authenticity determination of different varieties of Fritillaria.

Species profile of volatile organic compounds emission and health risk assessment from typical indoor events in daycare centers

Daycare centers (DCCs) play an instrumental role in early childhood development, making them a significant indoor environment for a large number of children globally. Amidst routine DCC activities, young children are exposed to a myriad of volatile organic compounds (VOCs), potentially impacting their health. Therefore, this study aims to investigate the VOC emissions during typical DCCs activities and evaluate respective health risk assessments. Employing a full-scale experimental setup within a well-controlled climate chamber, research was conducted into VOC emissions during three typical DCC events: arts-and-crafts (painting, gluing, modeling), cleaning, and sleeping activities tied to mattresses. The research identified 96 distinct VOCs, grouped into twelve categories, from 20 different events examined. Each event exhibited a unique VOC fingerprint, pinpointing potential source tracers. Also, significant variations in VOC emissions from different events were demonstrated. For instance, under cool & dry conditions, acrylic painting recorded high total VOC concentrations of 808 μg/m3, whereas poster painting showed only 58 μg/m3. Given these disparities, the study emphasizes the critical need for carefully selecting arts-and-crafts materials and cleaning agents in DCCs to effectively reduce VOC exposure. It suggests ventilating new mattresses before use and regular mattress check-ups to mitigate VOCs exposure during naps. Importantly, it revealed that certain events resulted in VOC levels exceeding the 10−5 cancer risk thresholds for younger children. Specifically, tetrachloroethylene and styrene from used mattresses in cool & dry conditions, ethylene oxide from new mattresses in warm & humid conditions, and styrene, during sand modeling in both conditions, were the key compounds contributing to this risk. These findings highlight the critical need for age-specific health risk assessments in DCCs. This study highlights the significance of understanding the profiles of VOC emissions from indoor events in DCCs, emphasizing potential health implications and laying a solid foundation for future investigations in this field.

Artificial nose of scalable plasmonic array gas sensor for Multi-Dimensional SERS recognition of volatile organic compounds

Gas sensing is one kind of promising analytical technique for high-flux screening and evaluation. Volatile organic compounds (VOCs) analysis by surface-enhanced Raman spectroscopy (SERS) is arising but usually focuses on a single species of VOCs due to the limitations of complexity, stability, and accuracy in practical applications. Canine animals have a sensitive sense of smell due to their large number of olfactory cells. Inspired by this, here we innovatively integrate scalable plasmonic arrays and multi-dimensional chemometrics for simultaneous SERS detection of multiple food-borne VOCs. Both direct and indirect SERS strategies are integrated by coating the array surface with MOFs or different monolayers to provide multi-dimensional recognition and readouts. Four species of VOCs including bacterial metabolites, hydrogen sulfide, aldehyde, and biogenic amine were selectively captured and produced unique SERS spectral profiles. The multi-dimensional outputs greatly increase the dimensionality of VOC fingerprints, thereby significantly improving the sensitivity, reliability, and accuracy for freshness discrimination and forecasting in real food smell evaluation. By virtue of multi-dimensional SERS recognition and machine learning, the array gas sensor shows higher accuracy than traditional SERS analysis and is a promising platform for in situ, real-time, and high-flux gas sensing and inspection.

Exhaled VOC Biomarkers from Rats Injected with PMs from Thirty-One Major Cities in China.

Particulate matter (PMs) of different origins can cause diverse health effects. Here, a homemade box was used to facilitate real-time measurements of breath-borne volatile organic compounds (VOCs) by gas chromatography-ion mobility spectrometry. We have tracked exhaled VOC changes in 228 Wistar rats that were injected with water-soluble PM suspension filtrates (after 0.45 μm) from 31 China cities for 1 h to up to 1-6 days during the experiments. Rats exposed to the filtrates exhibited significant changes in breath-borne VOCs within hours, featuring dynamic fluctuations in the levels of acetone, butan-2-one, heptan-2-one-M, acetic acid-M, and ethanol. Subsequently, on the fifth to sixth day after the injection, there was a notable increase in the proportion of aldehydes (including hexanal-M, hexanal-D, pentanal, heptanal-M, and (E)-2-hexenal). The 10 dynamic VOC fingerprint patterns mentioned earlier showcased the capability to indirectly differentiate urban PM toxicity and categorize the 31 cities into four distinct groups based on their health effects. This study provides valuable insights into the mechanisms of exhaled VOCs and underscores their critical role as biomarkers for differentiating the toxicity of different PMs and detecting the early signs of potential diseases. The results from this work also provide a scientific basis for city-specific air pollution control and policy development.

Dynamic evolution of volatile organic compounds in infant formula during storage: Insights from gas chromatography-ion mobility spectrometry

The flavor profile of infant formula (IF) determines its overall acceptability and palatability, significantly impacting its desirability for infants, while the presence of off-flavors challenges the feeding experience and IF quality, even may lead to the rejection by infants. In this study, the dynamic changes in volatile organic compounds (VOCs) during 12 weeks of IF storage at 4 °C–60 °C were monitored by Gas chromatography-ion mobility spectrometry (GC-IMS) for capturing the fingerprints of VOCs. The GC-IMS revealed that a total of 44 VOCs, including acids, alcohols, aldehydes, esters, ketones, and furans. The alternative principal component analysis (PCA) and Sankey diagram in this study offered a comprehensive tracing of the dynamic changes in VOCs, providing valuable implications for the optimization of IF quality control, assessment for validity period and origin tracking in the food industrial.

Machine-learning-assisted sensor array for detecting COVID-19 through simulated exhaled air

Reverse transcription polymerase chain reaction (RT-PCR), the primary test for COVID-19, requires complicated sample collection and several hours to obtain results. Breath test for exhaled volatile organic compounds (VOCs) has gained substantial research attention as a simple non-invasive and fast screening method. However, a unique VOC fingerprint as a potential prognostic biomarker is still unavailable. Accordingly, this study prepared simulated VOC gases to test the classification performance of a sensing system. The simulated VOC gases were selected according to the actual composition of the exhaled breath of patients with acute respiratory diseases, including COVID-19. Two sets of metal oxide sensor arrays, comprising eight commercial sensors and eight Advanced Institute of Science and Technology (AIST) laboratory-made sensors, were prepared to test their sensing ability for the simulated gases. The principal component analysis (PCA) results revealed that the AIST sensors had better sensing ability than the commercial sensors. Moreover, the recursive feature elimination cross-validation (RFECV) of random forest (RF) further confirmed the superiority of the AIST sensors over the commercial sensors. An artificial neural network (ANN) with excellent prediction performance for gas concentration was developed. This study provides a promising method for rapidly screening respiratory diseases.

Investigation of 60Co Irradiation on the Volatile Organic Compounds from Finger Citron (Citri Sarcodactylis Fructus) Using GC-IMS.

In recent years, as the desire for a healthy lifestyle has become more widespread, consumers are gaining an increasing appreciation for safe, high-quality food. Researchers are constantly seeking new ways to protect foods from insect pests and fungi. This study used GC-IMS to analyze the volatile organic compounds and flavor characteristics of Finger Citron in response to different doses of 60Co irradiation. The principal component analysis method was used to explore the overall differences in flavor spectra, and a total of 60 compounds were identified. The fingerprints of volatile organic compounds in the samples showed that the volatile organic compounds with doses of 60Co irradiation in about 0 kGy and 5 kGy are similar, while the 10 kGy samples are quite different. The PCA results showed that the similarity between 0 kGy and 5 kGy was slightly higher, and the difference between 10 kGy and other samples was greater. Therefore, it was determined that 60Co irradiation with a 10 kGy intensity has a significant influence on the content of volatile oils components, while 60Co irradiation with a 5 kGy intensity has little effect. Irradiation technology is demonstrated as a promising method of food sterilization, but the irradiation dose and chemical composition must be taken into consideration.

Influence of 60Co-γ Irradiation on the Components of Essential Oil of Curcuma.

The gas chromatography-ion mobility spectrometry (GC-IMS) method is a new technology for detecting volatile organic compounds. This study was carried out to evaluate the effects of volatile aroma compounds of Curcuma essential oils (EOs) after 60Co radiation by GC-IMS. Dosages of 0, 5, and 10 kGy of 60Co were used to analyze EOs of Curcuma after 60Co irradiation (named EZ-1, EZ-2, and EZ-3). The odor fingerprints of volatile organic compounds in different EOs of Curcuma samples were constructed by headspace solid-phase microextraction and GC-IMS after irradiation. The differences in odor fingerprints of EOs were compared by principal component analysis (PCA). A total of 92 compounds were detected and 65 compounds were identified, most of which were ketones, aldehydes, esters, and a small portion were furan compounds. It was found that the volatile matter content of 0 kGy and 5 kGy was closer, and the use of 10 kGy 60Co irradiation would have an unstable effect on the EOs. In summary, it is not advisable to use a higher dose when using 60Co irradiation for sterilization of Curcuma. Due to the small gradient of irradiation dose used in the experiment, the irradiation dose can be adjusted appropriately according to the required sterilization requirements during the production and storage process of Curcuma to obtain the best irradiation conditions. GC-IMS has the advantages of GC's high separation capability and IMS's fast response, high resolution, and high sensitivity, and the sample requires almost no pretreatment; it can be widely used in the analysis of traditional Chinese medicines containing volatile components. It is shown that irradiation technology has good application prospects in the sterilization of traditional Chinese medicines, but the changes in irradiation dose and chemical composition must be paid attention to.

Analysis of the Volatile Organic Compound Fingerprint of Greek Grape Marc Spirits of Various Origins and Traditional Production Styles

The most well-known traditional Greek grape marc distillate made from winemaking pomace is called “Tsipouro”. Its production involves various grape pomace cultivars, preparation protocols, and anise-flavoring or not, and it should be a colorless liquid with intense organoleptic properties due to the raw materials used in its production and have a minimum alcoholic strength of 37.5% by volume. This study aimed to characterize the volatilome of tsipouro products by covering as many geographical areas and production styles as possible, as there is a lack of characterization of the aromatic composition of this Greek traditional alcoholic beverage. A Headspace Solid Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS) method was applied in 60 samples, resulting in the identification and semi-quantification of over 90 volatile compounds. The statistical analysis pointed out the metabolites that characterized each traditional product group and underlined the influence of the geographical origin and the production protocol. Aniseed spirits from Northern Greece, Macedonia, Limnos Island, and Thessaly, produced from Muscat pomaces, were found to be richer in terpenes, terpenoids, and flavored compounds, attributing to product aroma and quality; different terpenoids were found to be dominant in Muscat distillates from different regions, showing the importance of geographical origin and production process. In conclusion, the results demonstrated the high aroma variability of the Greek Tsipouro, explained that this diversity is caused mainly by the raw material, and could be helpful in the better protection of the origin of this traditional product and the improvement of its quality.

Postharvest monitoring and consumer choice on traditional and modern apricot cultivars

Apricot (Prunus armeniaca L.) fruit qualities are affected by harvest date and rapid off-tree ripening progression that limits their shelf life and marketability. Nowadays, consumers are generally dissatisfied with the sensory quality of apricot fruit sold on large-scale retail channels. Pomological analysis (color, firmness, total soluble solids, and total acidity), volatile organic compounds fingerprint and sensory evaluation were performed during the postharvest in two different apricot genotypes with the objective to: (1) characterize and compare two different apricot cultivars at harvest and at different postharvest times; (2) understand how the sensory quality changes during the postharvest process; (3) elucidate which sensory quality parameters drive the consumer's choice. For this purpose, ‘Portici’ (traditional cultivar) and ‘Lady Cot’ (modern one) grown in the same environment, were evaluated at commercial maturity harvest and for the following 15 days. Results indicate that the sensory quality of the selected cultivars was different, with ‘Portici’ showing better performances in terms of aroma, sweetness and juiciness, while ‘Lady Cot’ stood out in terms of firmness. Results also indicate a different trend of the traits analyzed and of the shelf-life, that was reduced for the traditional cultivar.Graphical abstract

HS-SPME-GC-MS Untargeted Analysis of Normal Rat Organs Ex Vivo: Differential VOC Discrimination and Fingerprint VOC Identification.

The investigation of volatile organic compounds (VOCs) in human metabolites has been a topic of interest as it holds the potential for the development of non-invasive technologies to screen for organ lesions in vivo. However, it remains unclear whether VOCs differ among healthy organs. Consequently, a study was conducted to analyze VOCs in ex vivo organ tissues obtained from 16 Wistar rats, comprising 12 different organs. The VOCs released from each organ tissue were detected by the headspace-solid phase microextraction-gas chromatography-mass spectrometry technique. In the untargeted analysis of 147 chromatographic peaks, the differential volatiles of rat organs were explored based on the Mann-Whitney U test and fold change (FC > 2.0) compared with other organs. It was found that there were differential VOCs in seven organs. A discussion on the possible metabolic pathways and related biomarkers of organ differential VOCs was conducted. Based on the orthogonal partial least squares discriminant analysis and receiver operating characteristic curve, we found that differential VOCs in the liver, cecum, spleen, and kidney can be used as the unique identification of the corresponding organ. In this study, differential VOCs of organs in rats were systematically reported for the first time. Profiles of VOCs produced by healthy organs can serve as a reference or baseline that may indicate the presence of disease or abnormalities in the organ's function. Differential VOCs can be used as the fingerprint of organs, and future integration with metabolic research may contribute to the development of healthcare.

Evaluation of 60Co Irradiation on Volatile Components of Turmeric (Curcumae Longae Rhizoma) Volatile Oil with GC-IMS.

60Co irradiation is an efficient and rapid sterilization method. The aim of this work is to determine the changes in essential-oil composition under different irradiation intensities of 60Co and to select an appropriate irradiation dose with GC-IMS. Dosages of 0, 5, and 10 kGy of 60Co were used to analyze turmeric (Curcumae Longae Rhizoma) volatile oil after 60Co irradiation (named JH-1, JH-2, and JH-3). The odor fingerprints of volatile organic compounds in different turmeric volatile oil samples were constructed by headspace solid-phase microextraction and gas chromatography-ion mobility spectrometry (GC-IMS) after irradiation. The differences in odor fingerprints of volatile organic compounds (VOCs) were compared by principal component analysis (PCA). The results showed that 97 volatile components were detected in the volatile oil of Curcuma longa, and 64 components were identified by database retrieval. With the change in irradiation intensity, the volatile compounds in the three turmeric volatile oil samples were similar, but the peak intensity was significantly different, which was attributed to the change in compound composition and content caused by different irradiation doses. In addition, the principal component analysis showed that JH-2 and JH-3 were relatively correlated, while JH-1 and JH-3 were far from each other. In general, different doses of 60Co irradiation can affect the content of volatile substances in turmeric volatile oil. With the increase in irradiation dose, the peak area decreased, and so the irradiation dose of 5 kGy/min was better. It is shown that irradiation technology has good application prospects in the sterilization of foods with volatile components. However, we must pay attention to the changes in radiation dose and chemical composition.

Data-driven design of a multiplexed, peptide-sensitized transistor to detect breath VOC markers of COVID-19.

Exhaled human breath contains a rich mixture of volatile organic compounds (VOCs) whose concentration can vary in response to disease or other stressors. Using simulated odorant-binding proteins (OBPs) and machine learning methods, we designed a multiplex of short VOC- and carbon-binding peptide probes that detect a characteristic "VOC fingerprint". Specifically, we target VOCs associated with COVID-19 in a compact, molecular sensor array that directly transduces vapor composition into multi-channel electrical signals. Rapidly synthesizable, chimeric VOC- and solid-binding peptides were derived from selected OBPs using multi-sequence alignment with protein database structures. Selective peptide binding to targeted VOCs and sensor surfaces was validated using surface plasmon resonance spectroscopy and quartz crystal microbalance. VOC sensing was demonstrated by peptide-sensitized, exposed-channel carbon nanotube transistors. The data-to-device pipeline enables the development of novel devices for non-invasive monitoring, diagnostics of diseases, and environmental exposure assessment.

Variation in Leaf Volatile Emissions in Potato (Solanum tuberosum) Cultivars with Different Late Blight Resistance.

Volatile organic compounds (VOCs) play key roles in plant abiotic and biotic stress resistance, but even for widespread crops, there is limited information on variations in the magnitude and composition of constitutive VOC emissions among cultivars with varying stress resistance. The foliage VOC emissions from nine local and commercial potato cultivars (Alouette, Sarme, Kuras, Ando, Anti, Jõgeva Kollane, Teele, 1681-11, and Reet) with medium to late maturities and varying Phytophthora infestans (the causative agent of late blight disease) resistance backgrounds were analyzed to gain an insight into the genetic diversity of constitutive VOC emissions and to test the hypothesis that cultivars more resistant to Phytophthora infestans have greater VOC emissions and different VOC fingerprints. Forty-six VOCs were identified in the emission blends of potato leaves. The majority of the VOCs were sesquiterpenes (50% of the total number of compounds and 0.5-36.9% of the total emissions) and monoterpenes (30.4% of the total number of compounds and 57.8-92.5% of the total VOC emissions). Qualitative differences in leaf volatiles, mainly in sesquiterpenes, were related to the potato genotype background. Among the volatile groups, the monoterpenes α-pinene, β-pinene, Δ3-carene, limonene, and p-cymene, the sesquiterpenes (E)-β-caryophyllene and α-copaene, and green leaf volatile hexanal were the major volatiles in all cultivars. A higher share of VOCs known to have antimicrobial activities was observed. Interestingly, the cultivars were grouped into high and low resistance categories based on the VOC profiles, and the total terpenoid and total constitutive VOC emission scale positively with resistance. To support and expedite advances in breeding for resistance to diseases such as late blight disease, the plant research community must develop a fast and precise approach to measure disease resistance. We conclude that the blend of emitted volatiles is a fast, non-invasive, and promising indicator to identify cultivars resistant to potato late blight disease.

Gene-Regulated Release of Distinctive Volatile Organic Compounds from Stressed Living Cells.

Breath-borne volatile organic compounds (VOCs) have been increasingly studied as non-invasive biomarkers in both medical diagnosis and environmental health research. Recently, changes in breath-borne VOC fingerprints were demonstrated in rats and humans following pollutant exposures. In this study, the eukaryotic model Saccharomyces cerevisiae was used to study the release of cellular VOCs resulting from toxicant exposures (i.e., O3, H2O2, and CO2) and its underlying biological mechanism. Our results showed that different toxicant exposures caused the release of distinctive VOC profiles of yeast cells. The levels of ethyl acetate and ethyl n-propionate were altered in response to all the toxicants used in this study and could thus be targeted for future environmental toxicity monitoring. The RNA-seq results revealed significant changes in the metabolic or signaling pathways related to the ribosome, carbohydrate, and amino acid metabolisms after exposures. Notably, the shift from glycolysis to the pentose phosphate pathway of carbohydrate metabolism and the inhabitation of the aspartate pathway in the lysine synthesis was essential to the cellular antioxidation by providing reduced nicotinamide adenine dinucleotide phosphate (NADPH). The reprogrammed metabolisms could have resulted in the observed changes of VOCs released, e.g., the production of ethyl acetate for detoxification from yeast cells. This study provides further evidence that VOCs released from living organisms could be used to monitor and guard against toxic exposures while providing better mechanistic insights of the changes in breath-borne VOCs previously observed in rats and humans exposed to air toxicants.