Number Of Volatile Organic Compounds Research Articles

Health-based evaluation of ambient air measurements of PM2.5 and volatile organic compounds near a Marcellus Shale unconventional natural gas well pad site and a school campus

BackgroundLimited air monitoring studies with long-term measurements during all phases of development and production of natural gas and natural gas liquids have been conducted in close proximity to unconventional natural gas well pads.ObjectiveConducted in an area of Washington County, Pennsylvania, with extensive Marcellus Shale development, this study investigated whether operations at an unconventional natural gas well pad may contribute to ambient air concentrations of potential health concern at a nearby school campus.MethodsAlmost 2 years of air monitoring for fine particulate matter (PM2.5) and volatile organic compounds (VOCs) was performed at three locations between 1000 and 2800 feet from the study well pad from December 2016 to October 2018. PM2.5 was measured continuously at one of the three sites using a beta attenuation monitor, while 24-h stainless steel canister samples were collected every 6 days at all sites for analysis of 58 VOCs.ResultsMean PM2.5 concentrations measured during the different well activity periods ranged from 5.4 to 9.5 μg/m3, with similar levels and temporal changes as PM2.5 concentrations measured at a regional background location. The majority of VOCs were either detected infrequently or not at all, with measurements for a limited number of VOCs indicating the well pad to be a source of small and transient contributions.SignificanceAll measurement data of PM2.5 and 58 VOCs, which reflect the cumulative contributions of emissions from the study well pad and other local/regional air pollutant sources (e.g., other well pads), were below health-based air comparison values, and thus do not provide evidence of either 24-hour or long-term air quality impacts of potential health concern at the school.

Yeast Fermentation at Low Temperatures: Adaptation to Changing Environmental Conditions and Formation of Volatile Compounds.

Yeast plays a key role in the production of fermented foods and beverages, such as bread, wine, and other alcoholic beverages. They are able to produce and release from the fermentation environment large numbers of volatile organic compounds (VOCs). This is the reason for the great interest in the possibility of adapting these microorganisms to fermentation at reduced temperatures. By doing this, it would be possible to obtain better sensory profiles of the final products. It can reduce the addition of artificial flavors and enhancements to food products and influence other important factors of fermented food production. Here, we reviewed the genetic and physiological mechanisms by which yeasts adapt to low temperatures. Next, we discussed the importance of VOCs for the food industry, their biosynthesis, and the most common volatiles in fermented foods and described the beneficial impact of decreased temperature as a factor that contributes to improving the composition of the sensory profiles of fermented foods.

Quality control of raw hazelnuts by rapid and non-invasive fingerprinting of volatile compound release

Although hazelnuts are mostly consumed after toasting and mixed with other ingredients, for manufactures it is important to have efficient quality control tests on the raw product that they purchase from farmers and suppliers. This study explores the possibility to predict sensory quality of raw hazelnuts, classified according to industrial sensory evaluation, using volatilome analysis through Proton Transfer Reaction Mass Spectrometry (PTR-MS) rapid fingerprinting. Firstly, the link between volatile markers for different visual and sensory defects was investigated. Uncompliant hazelnuts showed higher concentrations for a larger number of volatile organic compounds (VOCs) than compliant samples, including some key hazelnuts odorants like 5-methyl-4-heptanone, 5-propyldihydro-2(3H)-furanone, octanal, 2,4-nonadienal and hexanal. Secondly, by mixing defective and good quality hazelnuts, the method sensitivity in recognizing defects percentage was determined. For about 13% of the detected mass peaks, the method was able to discriminate samples containing 20% of hazelnuts with unacceptable quality from good quality samples. Finally, unsupervised data clustering of VOCs fingerprints obtained with different precursor ions (H3O+, NO+ and O2+) provided a correct classification rate higher than 90% for all ions. The applied methodology is suitable to support sensory quality control programs of raw hazelnuts in confectionary industries.

In vivo and in vitro Volatile Constituents of the Flowers of Xylopia aromatica by HS‑SPME/GC-MS

Xylopia aromatica (Lam.) Mart. (Annonaceae) is a typical species from the Brazilian cerrado that presents medicinal properties. The plant is distinguished by its large white flowers which produce a pleasant fragrance. X. aromatica is characterized by a wide range of medicinal application. These characteristics have motivated us to investigate the flowers volatile organic compounds (VOCs) via in vivo and in vitro protocols by a headspace solid-phase microextraction (HS‑SPME) technique combined with gas chromatography-mass spectrometry (HS-SPME/GC‑MS). Four different fibers, extraction times and temperatures were the parameters changed to lead to the maximum profiling of the volatile constituents. Data were analyzed using principal component analysis (PCA). A total of 77 VOCs were extracted from the floral scent, with 52 and 68 extracted from in vivo and in vitro sampling, respectively, of which 48 were reported for the first time in the literature as volatile constituents from X. aromatica flowers. The extraction and identification of VOCs were successfully performed through HS-SPME/GC-MS. The PCA data allowed the identification of parameters that led to the maximum number of VOCs, which were polyacrylate (PA) and carboxen/polydimethylsiloxane (CAR/PDMS) fibers, 60 min extraction time and temperature of 29.0 °C. Among the volatile constituents identified, sesquiterpenes predominated, comprising about 61.04%.

Using Epoxidized Solution Polymerized Styrene-Butadiene Rubbers (ESSBRs) as Coupling Agents to Modify Silica without Volatile Organic Compounds.

Rubber used in tire is usually strengthened by nanofiller, and the most popular nanofiller for tire tread rubber is nano silica, which can not only strengthen rubber but also lower the tire rolling resistance to reduce fuel consumption. However, silica particles are difficult to disperse in the rubber matrix because of the abundant silicon hydroxyl on their surface. Silane coupling agents are always used to modify silica and improve their dispersion, but a large number of volatile organic compounds (VOCs) are emitted during the manufacturing of the nanosilica/rubber composites because of the condensation reaction between silane coupling agents and silicon hydroxyl on the surface of silica. Those VOCs will do great harm to the environment and the workers’ health. In this work, epoxidized solution polymerized styrene-butadiene rubbers (ESSBR) with different epoxy degrees were prepared and used as macromolecular coupling agents aimed at fully eliminating VOCs. Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) analyses verified that the different ESSBRs were successfully synthesized from solution polymerized styrene-butadiene rubbers (SSBR). With the help of the reaction between epoxy groups and silicon hydroxyl without any VOC emission, nanosilica can be well dispersed in the rubber matrix when SSBR partially replaced by ESSBR which was proved by Payne effect and TEM analysis. Dynamic and static mechanical testing demonstrated that silica/ESSBR/SSBR/BR nanocomposites have better performance and no VOC emission compared with Bis-(γ-triethoxysilylpropyl)-disulfide (TESPD) modified silica/rubber nanocomposites. ESSBR is very hopeful to replace traditional coupling agent TESPD to get high properties silica/rubber nanocomposites with no VOCs emission.

Liquid crystal nose (LC-nose): case of chiral networks

ABSTRACT Liquid crystalline networks based on compositions of cholesteric siloxanes and low molar mass compounds are studied as components of a liquid crystal nose (LC-nose) that is able to detect a number of volatile organic compounds (VOCs): ethanol, toluene, pyridine, and acetic acid. Selectivity to different VOCs is improved by means of copolymerisation with acrylic acid and blending with low molar mass compound (pentylcyclohexanecarboxylic acid). This modifies the properties of the liquid crystalline matrix by introducing hydrogen donors/acceptors and increases the matrix affinity to certain VOCs.

Odor pollution due to industrial emission of volatile organic compounds: A case study in Hefei, China

Abstract Odor pollution as an environmental nuisance has attracted a lot of public attention. A great number of volatile organic compounds are capable of causing odor problems, most of which are accompanied by adverse health effects. Volatile organic compound samples were collected from different sites in the high-tech industry development zone in Hefei, including various kinds of factories and residential areas. The samples were analyzed by gas chromatography and mass spectrometry detection, and the analysis results showed that the concentrations of total volatile organic compounds ranged from 285.30 to 1802.30 ppbv. Among the 80 specific volatile organic compounds studied, 46 compounds detected could lead to odor pollution according to the odor threshold. To provide comprehensive characterization of odor pollution, instrumental analysis combined with olfactory measurement were conducted in this study. Odor volatile organic compounds were characterized by using olfactory odor concentration, odor index and coefficient of divergence analysis methods. According to the results, the automobile components manufacturing plants and electric products plants exhibited the highest concentrations of odor volatile organic compounds among all the major emission sites, especially during the injection molding and spraying. Specifically, 1,4-diethylbenzene was the most abundant odorous contributor in this study. Furthermore, the profiles of each volatile organic compounds at the industrial sites were quite different from those at the residential sites, which can be deduced that the surrounding residential zones were not strongly affected by the volatile organic compounds emission from the industrial zones.

Knowing Me, Knowing You: Anal Gland Secretion of European Badgers (Meles meles) Codes for Individuality, Sex and Social Group Membership

European badgers, Meles meles, are group-living in the UK, and demarcate their ranges with shared latrines. As carnivores, badgers possess paired anal glands, but olfactory information on the content of badger anal gland secretion (AGS) is largely uninvestigated. Here, we examined the volatile organic compounds (VOCs) of AGS samples from 57 free-living badgers using solid-phase microextraction (SPME) and gas chromatography—mass spectrometry. AGS was rich in alkanes (C7–C15, 14.3% of identified compounds), aldehydes (C5–C14, 9.7%), phenols (C6–C15, 9.5%), alcohols (C5–C10, 7.3%), aromatic hydrocarbons (C6–C13, 6.8%), ketones (C6–C13, 6.3%) and carboxylic acids (C3–C12, 5.6%) and contained a variety of esters, sulfurous and nitrogenous compounds, and ethers. The number of VOCs per profile ranged from 20 to 111 (mean = 65.4; ± 22.7 SD), but no compound was unique for any of the biological categories. After normalization of the raw data using Probabilistic Quotient Normalization, we produced a resemblance matrix by calculating the Euclidian distances between all sample pairs. PERMANOVA revealed that AGS composition differs between social groups, and concentration and complexity in terms of number of measurable VOCs varies between seasons and years. AGS VOC profiles encode individual identity, sex and vary with female reproductive state, indicating an important function in intraspecific communication. Because AGS is excreted together with fecal deposits, we conclude that chemical complexity of AGS enables particularly latrine-using species, such as badgers, to advertise more complex individual-specific information than in feces alone.

Laboratory Estimation of Occupational Exposures to Volatile Organic Compounds During Nail Polish Application.

In the United States, there are more than 120,000 nail salons in which workers could be potentially exposed to a number of volatile organic compounds (VOCs) used in various procedures. Measuring workers exposure in the field is time-consuming and could be very expensive. The purpose of this study was to estimate the VOC levels in the proximity of workers in nail salons through simulating the application process of some popular nail polishes in a laboratory chamber. The worst-case scenario was defined as a worker's exposure during nail polish application to one set of fingernails every 15 minutes for an 8-hour shift (total nail sets = 32). Nail polish was applied on paper plates in a flow-controlled test chamber. Air was sampled during the application of five different nail polishes for 8 hours using passive air samplers and the experiment was triplicated. Passive samplers were used for VOCs and formaldehyde. In this worst-case scenario setting, a total of 17 VOCs were detected, with eight that were found in all the samples. The mean concentration of butyl acetate (161-330 ppm, parts per million) and ethyl acetate (440 ppm) exceeded the threshold limit value (TLV) of 150 ppm and 400 ppm, respectively. Formaldehyde was analyzed separately and the mean concentrations exceeded the TLV of 0.10 ppm in all types of nail polish, ranging from 0.12 ppm to 0.22 ppm. Occupational safety and health professionals could use these data to increase awareness of workers' potential exposure to high levels of VOCs in nail salons and recommend practical measures to reduce potential exposures.

MAX-DOAS measurements and vertical profiles of glyoxal and formaldehyde in Madrid, Spain

Glyoxal (CHOCHO) and formaldehyde (HCHO) are organic trace gases that play an important role in tropospheric chemistry as oxidation products of a number of volatile organic compounds (VOCs). In this study, we report year-round daytime measurements of glyoxal and formaldehyde in the urban atmosphere of Madrid, Spain. Their vertical concentration profiles were retrieved using the Multi AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique and a Radiative Transfer Model (RTM) that simulates solar photon paths through the atmosphere. The diurnal variations of HCHO show two distinct peaks during the day, in the early morning and late afternoon in spring and summer, while the second peak is shifted towards noon in autumn and winter, due to lower photolysis rates and more effective boundary layer accumulation of HCHO in those seasons. The HCHO surface mixing ratios range from 6 ppbv to 27 ppbv in spring-summer and from 10 ppbv to 30 ppbv in autumn-winter. Monthly hourly-averaged glyoxal surface mixing ratios in the early morning show higher values during winter, 2 ppbv, than in summer, 0.7 ppbv. We also evaluated the ratio between glyoxal and formaldehyde (RGF) surface mixing ratios, as an indicator of the nature of VOCs precursors. The RGF was also correlated with the measured NO2, which represents a direct signal of anthropogenic emissions, along with the VOCs emission inventories in Madrid. The RGF results yielded higher ratios in spring, 0.1–0.13, than in winter and autumn (in the range of 0.02–0.07) when NO2 levels were higher.

Influence of Benzyladenine on Metabolic Changes in Different Rose Tissues.

Two modern rose varieties, Floribunda and Hybrid Tea, were used to analyze and identify metabolic changes after foliar application with benzyladenine (BA). Volatile organic compounds (VOCs) as metabolites were detected. Two pairs of doses of BA, at 11.16 and 17.87 mg/cm2, and 7.17 and 12.26 mg/cm2 were applied to the foliage of Hybrid Tea and Floribunda, respectively. Sampling time was optimized and treatment duration was 4 weeks. After treatment, the volatiles from the treated and untreated control roses were extracted using headspace solid-phase microextraction (HS-SPME) technology by three-phase fiber 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) and analyzed by gas chromatography (GC) coupled with a flame ionization detector (FID), and with mass spectrometry (GC-MS).The results showed that BA and its dose rate led to metabolic changes of treated roses in comparison with untreated controls. The number of VOCs extracted and detected from leaves, stem, rhizosphere and whole plants from the two rose varieties at doses rate of 17.87 and 12.26 mg/cm2 were 43, 65, 40 and 68 compounds for each plant material, respectively, for both rose varieties. Whilst the VOCs extracted and detected from both rose varieties for leaves, stem, rhizosphere and whole plants were 38, 61, 34 and 66 compounds for each plant material, respectively. The results demonstrate that some volatiles, such as 4-Heptyn-2-ol, Phenyl methyl ether and 3-Methyl-apopinene, increased with increasing doses of BA; these compounds are aroma chemicals with a very powerful smell. This study shows that BA treatments can have a significant effect on metabolite changes in different rose tissues. This method could be applied to other floriculture plants.

Automated Dual-Chamber Sampling System to Follow Dynamics of Volatile Organic Compounds Emitted by Biological Specimens.

Growth of microorganisms is often accompanied by the release of volatile organic compounds (VOCs). The released VOCs may qualitatively or quantitatively reflect the physiological states of microbial cultures. A number of VOCs are produced during microbial degradation of organic matter accompanying food spoilage. In order to characterize the dynamics of microbial VOC production, and enable time-dependent analysis, we have constructed a dual-chamber sampling system and coupled it online with mass spectrometry (MS). The biological specimen is placed in a gas-tight sampling chamber. A carrier gas is introduced to the chamber periodically to transfer the VOCs present in the specimen headspace to the atmospheric-pressure chemical-ionization interface of a triple-quadrupole mass spectrometer. A control or blank spectrum is recorded before the specimen spectrum is recorded at each time point, enabling signal comparison and subtraction. The custom-made electronic control unit, incorporating three Arduino microcontrollers, operates six pinch valves and a miniature air compressor and triggers MS-data acquisition. The automated dual-chamber sampling system was first tested using standard mixtures to verify its analytical performance. To demonstrate the usefulness of this system in the studies of microbial volatomes, we implemented it in real-time monitoring of the growth of baker's yeast ( Saccharomyces cerevisiae), fructification of golden oyster mushroom ( Pleurotus citrinopileatus), and microbial degradation of a food-related sample (Pacific white shrimp, Litopenaeus vannamei). The recorded VOC signals show characteristic temporal profiles with transient bands or plateaus corresponding to different stages of microbial growth and putrefaction processes.

Bacillus velezensis, a potential and efficient biocontrol agent in control of pepper gray mold caused by Botrytis cinerea

Plant gray mold disease caused by necrotrophic pathogen Botrytis cinerea, has been a serious threat to many important crops. It is urgent and necessary to seek an effective and environmentally friendly control strategy to control grey mold disease during the crop production. Moreover, it is also urgently needed to clear understand how the strategy works. To screening an efficient biocontrol agent in control of gray mold disease caused by B. cinerea, one hundred strains, which have the potential in controlling plant diseases, were selected from our laboratory’s strain library, and employed to our research. The results in the study indicated that Bacillus velezensis could act as a potential and efficient biocontrol agent (BCA), and two B. velezensis strains 5YN8 and DSN012 were screened out with high antagonistic and hydrolase activity, which could significantly control pepper gray mold disease and promote the pepper growth. Further deeply study on biocontrol mechanism indicated that B. velezensis could suppress the growth and spore formation of B. cinerea by secreting some secondary metabolites or releasing numbers of volatile organic compounds (VOCs). In the other hand, we also found that B. velezensis could trigger plant basal immunity. The BCA could increase the expression of SA signal markers and plant defense related genes. It was able to induce hydrogen peroxide accumulation and plant related enzyme activities in leaves of pepper as well. This study provides another high-efficiency, and potential strategies for the biological control of gray mold disease. It is the first report of B. velezensis strain which can control gray mold disease, In addition, it is also the first to comprehensively illustrate how the strains can efficiently protect pepper from B. cinerea attacking.

Pungency and volatile compounds in some Spanish onion cultivars

Onion (Allium cepa L.) is the most representative species which forms part of the Alliaceae family. Onion is one of the most important vegetal crops throughout the world. The presence of sulfur compounds in the alliums greatly influences its aromatic characteristics and provides the particular smell and spicy flavour known as pungency. The sulfur volatiles compounds are formed by enzymatic reaction, the hydrolysis by allinase of S-alk(en)yl-L-cysteine sulfoxides. This work characterizes the volatile compounds and pyruvic acid content of four cultivars of autochthonous onions from a vegetable germplasm bank in Zaragoza (Spain). Onions were grown in a greenhouse under the same conditions of time, temperature, climate, soil, and nutrient supply and samples extracted after peeling the onions. The content in acid pyruvic presented values between 4,96 and 13,8 μmol g-1 fw of acid pyruvic. The aroma volatiles of the cultivars were analysed by gas chromatography coupled with mass spectrometry and the aroma profiles were similar with a total of 106 volatile compounds identified in the four cultivars. Half of the volatiles were sulfur derived compounds. The higher pungency and pyruvic acid concentration was found in the cultivar ‘Betanzos’, which also contained the largest number of volatile organic compounds and 26 exclusive volatiles when compared with the other cultivars.

Smell of cells: Volatile profiling of stem- and non-stem cell proliferation

Bacterial and cell cultures are known to emit a large number of volatile organic compounds (VOCs). Conventional biochemical methods are often destructive, time-consuming and expensive. In contrast, VOC analysis of headspace over cultures may offer a non-destructive alternative for the monitoring of cell proliferation and metabolism. VOC profiles from cultures of murine pluripotent stem cells and fibroblasts were assessed every 24 h for 3 days. Pure cell media were measured as parallel controls. VOC analysis was highly standardized with respect to time of measurement and phases of cell growth. Cultures were grown in custom-made inert boxes. In order to determine the effects of fresh media supply on VOC emissions, both cell types were cultured with and without daily media exchange. VOCs from headspace were preconcentrated by means of needle trap micro-extraction and analysed by gas chromatography-mass spectrometry (GC-MS). Murine pluripotent stem cells emitted increasing concentrations of thiirane and methyl-methoxy-hydroxy-methyl-amine (MMHA). Substance concentration correlated with cell numbers. Murine fibroblasts did not emit thiirane or MMHA. Concentrations of aldehydes, especially benzaldehyde, were lower in both cell cultures than in pure media samples. Daily media exchange resulted in higher cell numbers, but had no major effects on VOC concentrations emitted from the cells. Investigation and monitoring of volatile substances such as thiirane and MMHA may enhance the understanding of stem cell properties and lead to a destruction-free characterization of pluripotent stem cells.

Rapid Evaluation of Poultry Meat Shelf Life Using PTR-MS

The use of proton transfer reaction mass spectrometry (PTR-MS) for freshness classification of chicken and turkey meat samples was investigated. A number of volatile organic compounds (VOCs) were selected based on the correlation (> 95%) of their concentration during storage at 4 °C over a period of 5 days with the results of the microbial analysis. In order to verify if the selected compounds are not sample-specific, a number of samples sourced from various retailers were classified using the concentration of these compounds in the samples’ volatile fraction as input variables. The classification was performed using the support vector machines (SVM) supervised pattern recognition algorithm. It was concluded that it is possible to evaluate the shelf life of meat samples obtained from the same source based on the results of a prior analysis. The PTR-MS fingerprint approach might supplement the currently used methods of shelf life evaluation of poultry due to the short time and non-destructive nature of measurement and ease of quantitative analysis.

Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

Abstract. Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH4) and ammonia (NH3) downwind of dairy cattle, beef cattle, sheep and chicken CAFO facilities in northeastern Colorado using a hydronium ion time-of-flight chemical-ionization mass spectrometer (H3O+ ToF-CIMS), which can detect numerous VOCs. Regional measurements of CAFO emissions in northeastern Colorado were also performed using the NOAA WP-3D aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. Alcohols and carboxylic acids dominate VOC concentrations and the reactivity of the VOCs with hydroxyl (OH) radicals. Sulfur-containing and phenolic species provide the largest contributions to the odor activity values and the nitrate radical (NO3) reactivity of VOC emissions, respectively. VOC compositions determined from mobile laboratory and aircraft measurements generally agree well with each other. The high time-resolution mobile measurements allow for the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the emissions of ethanol are primarily associated with feed storage and handling. Based on mobile laboratory measurements, we apply a multivariate regression analysis using NH3 and ethanol as tracers to determine the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls, carboxylic acids and sulfur-containing species. Emissions of phenolic species and nitrogen-containing species are predominantly associated with animals and their waste.

Domestication effects in European breeding history of strawberry demonstrated by aroma compound pattern

Domestication of plants results in wanted improvements but also in negative side-effects effects depending on the genetic constitution of the material, in particular, after intense breeding. Negative effects, for example, losses in aroma and resistances are obvious for horticulturists as well as for consumers. Molecular studies demonstrated the loss of allelic diversity (Gil-Ariza et al., 2009; Horvath et al., 2011). In this study, we investigated 50 old and modern European strawberry cultivars released between 1849 and 2016. All available fruit from ten plants per cultivar were harvested and analyzed as a batch by immersion stir bar sorptive extraction-gas chromatography-quadrupole mass spectrometry (lmm-SBSE-GC-qMS). The sum of all detected 82 volatile organic compounds (VOCs) including 18 character impact compounds were evaluated with respect to the breeding history. Overall, old cultivars as a group showed a much higher diversity in aroma patterns in quality and in quantity of the sum and the quantity of single VOCs in comparison to modern cultivars. A high number of VOCs showed a much higher range of values (relative concentrations) in old cultivars. Some VOCs are lacking in modern cultivars, for example, methyl anthranilate is present in nearly the half of the cultivars released before 1952 whereas no modern cultivar showed detectable amounts of this important ester characterized by a flowery, wood-strawberry-like odour. On the other hand, a third of the old cultivars did not show the aroma-active compound ydodecalactone in contrast to the modern cultivars with 100% detectability. Linalool as a key compound with flowery and citrus-like odor impression varied in cultivars released before 1960 from zero to a value of 106 relative concentration. In modern cultivars, it was detectable throughout the collection with values of 3 to 67 relative concentrations. The data showed changes in the profile of aroma in the process of domestication. The complaints about the flavor and the low sensorial quality of modern cultivars are reflected to a certain extend in the aroma patterns.

Volatile organic compounds of Thai honeys produced from several floral sources by different honey bee species.

The volatile organic compounds (VOCs) of four monofloral and one multifloral of Thai honeys produced by Apis cerana, Apis dorsata and Apis mellifera were analyzed by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography and mass spectrometry (GC-MS). The floral sources were longan, sunflower, coffee, wild flowers (wild) and lychee. Honey originating from longan had more VOCs than all other floral sources. Sunflower honey had the least numbers of VOCs. cis-Linalool oxide, trans-linalool oxide, ho-trienol, and furan-2,5-dicarbaldehyde were present in all the honeys studied, independent of their floral origin. Interestingly, 2-phenylacetaldehyde was detected in all honey sample except longan honey produced by A. cerana. Thirty-two VOCs were identified as possible floral markers. After validating differences in honey volatiles from different floral sources and honeybee species, the results suggest that differences in quality and quantity of honey volatiles are influenced by both floral source and honeybee species. The group of honey volatiles detected from A. cerana was completely different from those of A. mellifera and A. dorsata. VOCs could therefore be applied as chemical markers of honeys and may reflect preferences of shared floral sources amongst different honeybee species.

Evaluation of Penicillium expansum for growth, patulin accumulation, nonvolatile compounds and volatile profile in kiwi juices of different cultivars

Patulin (PAT) contamination and changes of nonvolatile and volatile compounds caused by Penicillium expansum in fresh juices of 8 kiwi cultivars were investigated. Growth and PAT production of P. expansum were greater at 25°C than at 4°C. P. expansum grew in kiwi juices under pH ranging from 2.75 to 3.27 and produced 45.10-268.88μg/mL of PAT at 25°C. Decreases occurred in malic acid and soluble protein; while consumption and production simultaneously happened for reducing sugar, total soluble solid, titratable acid, citric acid, ascorbic acid and total phenolics. A large number of volatile organic compounds (VOCs) were produced during infection and each cultivar presented a distinct profile. Most of the alcohols, acids, ketones and phenols increased while aldehydes decreased. VOCs that were specific to infected kiwi juices are potential biomarkers for GC-MS analysis of kiwifruit infected by P. expansum.