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1.
Environ Sci Technol ; 58(25): 11105-11117, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38866390

ABSTRACT

Volatile chemical products (VCPs) are increasingly recognized as significant sources of volatile organic compounds (VOCs) in urban atmospheres, potentially serving as key precursors for secondary organic aerosol (SOA) formation. This study investigates the formation and physicochemical transformations of VCP-derived SOA, produced through ozonolysis of VOCs evaporated from a representative room deodorant air freshener, focusing on the effects of aerosol evaporation on its molecular composition, light absorption properties, and reactive oxygen species (ROS) generation. Following aerosol evaporation, solutes become concentrated, accelerating reactions within the aerosol matrix that lead to a 42% reduction in peroxide content and noticeable browning of the SOA. This process occurs most effectively at moderate relative humidity (∼40%), reaching a maximum solute concentration before aerosol solidification. Molecular characterization reveals that evaporating VCP-derived SOA produces highly conjugated nitrogen-containing products from interactions between existing or transformed carbonyl compounds and reduced nitrogen species, likely acting as chromophores responsible for the observed brownish coloration. Additionally, the reactivity of VCP-derived SOA was elucidated through heterogeneous oxidation of sulfur dioxide (SO2), which revealed enhanced photosensitized sulfate production upon drying. Direct measurements of ROS, including singlet oxygen (1O2), superoxide (O2•-), and hydroxyl radicals (•OH), showed higher abundances in dried versus undried SOA samples under light exposure. Our findings underscore that drying significantly alters the physicochemical properties of VCP-derived SOA, impacting their roles in atmospheric chemistry and radiative balance.


Subject(s)
Aerosols , Volatile Organic Compounds , Volatile Organic Compounds/chemistry , Oxidation-Reduction , Air Pollutants/chemistry , Reactive Oxygen Species/chemistry , Atmosphere/chemistry
2.
Biomolecules ; 14(6)2024 Jun 16.
Article in English | MEDLINE | ID: mdl-38927113

ABSTRACT

Among the Moscato grapes, Moscato Giallo is a winegrape variety characterised by a high content of free and glycosylated monoterpenoids, which gives wines very intense notes of ripe fruit and flowers. The aromatic bouquet of Moscato Giallo is strongly influenced by the high concentration of linalool, geraniol, linalool oxides, limonene, α-terpineol, citronellol, hotrienol, diendiols, trans/cis-8-hydroxy linalool, geranic acid and myrcene, that give citrus, rose, and peach notes. Except for quali-quantitative analysis, no investigations regarding the isotopic values of the target volatile compounds in grapes and wines are documented in the literature. Nevertheless, the analysis of the stable isotope ratio represents a modern and powerful tool used by the laboratories responsible for official consumer protection, for food quality and genuineness assessment. To this aim, the aromatic compounds extracted from grapes and wine were analysed both by GC-MS/MS, to define the aroma profiles, and by GC-C/Py-IRMS, for a preliminary isotope compound-specific investigation. Seventeen samples of Moscato Giallo grapes were collected during the harvest season in 2021 from two Italian regions renowned for the cultivation of this aromatic variety, Trentino Alto Adige and Veneto, and the corresponding wines were produced at micro-winery scale. The GC-MS/MS analysis confirmed the presence of the typical terpenoids both in glycosylated and free forms, responsible for the characteristic aroma of the Moscato Giallo variety, while the compound-specific isotope ratio analysis allowed us to determine the carbon (δ13C) and hydrogen (δ2H) isotopic signatures of the major volatile compounds for the first time.


Subject(s)
Gas Chromatography-Mass Spectrometry , Vitis , Volatile Organic Compounds , Wine , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Gas Chromatography-Mass Spectrometry/methods , Wine/analysis , Vitis/chemistry , Tandem Mass Spectrometry/methods , Carbon Isotopes/analysis , Fruit/chemistry , Odorants/analysis
3.
Int J Mol Sci ; 25(12)2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38928142

ABSTRACT

In this study, Fe3O4 nanoparticles (FeNPs) decorated with halogenated perylene diimides (PDIs) have been used for capturing VOCs (volatile organic compounds) through noncovalent binding. Concretely, we have used tetrachlorinated/brominated PDIs as well as a nonhalogenated PDI as a reference system. On the other hand, methanol, ethanol, propanol, and butanol were used as VOCs. Experimental studies along with theoretical calculations (the BP86-D3/def2-TZVPP level of theory) pointed to two possible and likely competitive binding modes (lone pair-π through the π-acidic surface of the PDI and a halogen bond via the σ-holes at the Cl/Br atoms). More in detail, thermal desorption (TD) experiments showed an increase in the VOC retention capacity upon increasing the length of the alkyl chain, suggesting a preference for the interaction with the PDI aromatic surface. In addition, the tetrachlorinated derivative showed larger VOC retention times compared to the tetrabrominated analog. These results were complemented by several state-of-the-art computational tools, such as the electrostatic surface potential analysis, the Quantum Theory of Atoms in Molecules (QTAIM), as well as the noncovalent interaction plot (NCIplot) visual index, which were helpful to rationalize the role of each interaction in the VOC···PDI recognition phenomena.


Subject(s)
Alcohols , Alcohols/chemistry , Perylene/chemistry , Perylene/analogs & derivatives , Volatile Organic Compounds/chemistry , Halogens/chemistry , Magnetite Nanoparticles/chemistry , Quantum Theory
4.
J Hazard Mater ; 475: 134843, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-38870859

ABSTRACT

ß-Carboline heterocyclic amines (ß-CHAs), known for their synergistic neurotoxic and carcinogenic effects, are predominantly produced by humans through cigarette smoke and food and are found particularly in meats cooked at high temperatures. Few studies have explored the differences in the mechanisms of accumulation of ß-CHAs in smoked meat and meat processed at high temperatures. In this research, the concentration of ß-CHAs in smoked meats prepared using a variety of wood materials was measured using LCMS/MS. Additionally, key volatile organic compound markers associated with ß-CHAs accumulation in smoke were identified through GCMS and multivariate statistical analysis and subsequently confirmed in a chemical simulation system. Three types of strainers, each with a distinct aperture size, were used to assess the efficacy of particle filtration in reducing ß-CHAs levels in smoked meat. The findings indicated that smoke exposure indeed increases the ß-CHAs content of meat. However, only the strainer capable of filtering PM2.5-sized particles reduced the amount of ß-CHAs present compared to the control group. In contrast, strainers with larger pore sizes facilitated excessive accumulation of ß-CHAs. The presence of aldehydes such as 1 H-pyrrole-2-carboxaldehyde, 5-methylfurfural, benzaldehyde, furfural, and nonanal exhibited a positive correlation with the accumulation of ß-CHAs. Conversely, phenolic compounds, including 2-methoxy-4-vinylphenol, 2-methoxy-5-methylphenol, p-cresol, phenol, 2-methoxy-4-(1-propenyl)-, (Z)-, phenol, 3-ethyl-, and phenol, 4-ethyl-2-methoxy-, showed a negative correlation. Thus, filters made from chelated carbonyl trap materials both chemically and physically disrupt the buildup of ß-CHAs in smoked meats. The use of this approach will not only improve the quality of these products but will also contribute to decreasing the amount of inhalation pollutants released into the environment.


Subject(s)
Carbolines , Smoke , Carbolines/chemistry , Smoke/analysis , Amines/chemistry , Amines/analysis , Animals , Meat/analysis , Meat Products/analysis , Cooking , Wood/chemistry , Particulate Matter/analysis , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Heterocyclic Compounds/analysis
5.
J Agric Food Chem ; 72(26): 14851-14864, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38841998

ABSTRACT

Liquor-pairing food is a common dietary combination. Baijiu and peanuts are unquestionably a classic pairing in China. But no one has explained why. Its alteration in baijiu flavor was studied using multiple sensory evaluation, as well as nontargeted proton-transfer reaction mass spectrometry coupled with GC × GC-MS. Multiple statistical analyses were used to discover the changes in the retronasal aroma and its contribution to baijiu flavor. It showed that the consumption of peanuts enhances the burst intensity of ester aroma (0.814-1.00) and Jiao aroma (0.889-0.963) but decreases the aftertaste of baijiu (p < 0.05). Meanwhile, it increases the release intensity and advances the burst time of baijiu retronasal aroma (p < 0.05), suppressing its aftertaste through the retention effect of the food matrix, the changes in oral processing, and cross-modal interactions. Hydrophobicity, polarity, and chemical characteristics are key factors of the uneven impact of accompanying food to aroma compounds. Esters, especially ethyl caprylate (2103 ± 927 to 51.9 ± 4.05) is most impacted by peanuts and contributes most to baijiu flavor changes. Pyrazines from peanut enhance the Qu-aroma, grain aroma, and Chen aroma in baijiu flavor. Therefore, we revealed the chemical nature of baijiu-peanut combination and help to optimize baijiu consumption experience.


Subject(s)
Arachis , Gas Chromatography-Mass Spectrometry , Odorants , Taste , Humans , Arachis/chemistry , Odorants/analysis , Adult , Female , Male , Young Adult , China , Volatile Organic Compounds/chemistry , Flavoring Agents/chemistry , Alcoholic Beverages/analysis , Smell , Middle Aged
6.
J Agric Food Chem ; 72(26): 14874-14886, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38885647

ABSTRACT

A modified aroma extract dilution approach (AEDA), followed by the determination of flavor dilution (FD) factors, a quantitative analysis and calculation of the relative flavor activity (RFA) and odor activity values (OAVs) as well as recombination experiments were conducted to evaluate the odor- and taste-relevant components of cold-pressed Citrus latifolia peel oil. A 2-fold concentration by distillation and reanalysis, compared with the original oil, revealed relevant components. Partition of the odor-active substances into four reconstitution groups according to their respective FD factors, followed by a recombination, allowed for a better understanding of the contribution of each FD-factor group to the overall aroma. Especially α-pinene, limonene, γ-terpinene, and 7-methoxycoumarin contribute significantly to the distinct aroma profile of C. latifolia. Heptadecanal (CAS 629-90-3) was described for the first time as an odor-active substance in an enriched C. latifolia peel oil. Campherenyl acetate (CAS 18530-07-9) was identified in nature for the first time and described with a herbal, minty and citrus-like odor. The odor profile of the final recombinant mixture, containing 36 components, was similar to cold-pressed C. latifolia peel oil for most descriptors, whereas the taste profile was described as more aldehydic and citral-like.


Subject(s)
Citrus , Flavoring Agents , Gas Chromatography-Mass Spectrometry , Odorants , Taste , Citrus/chemistry , Odorants/analysis , Flavoring Agents/chemistry , Humans , Fruit/chemistry , Volatile Organic Compounds/chemistry , Smell , Plant Oils/chemistry , Female , Limonene/chemistry , Limonene/analysis , Male , Adult
7.
J Agric Food Chem ; 72(26): 14865-14873, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38912709

ABSTRACT

Counterfeit Baijiu has been emerging because of the price variances of real-aged Chinese Baijiu. Accurate identification of different vintages is of great interest. In this study, the combination of gas chromatography-mass spectrometry (GC-MS) and proton nuclear magnetic resonance (1H NMR) spectroscopy was applied for the comprehensive analysis of chemical constituents for Maotai-flavor Baijiu. Furthermore, a novel data fusion strategy combined with machine learning algorithms has been established. The results showed that the midlevel data fusion combined with the random forest algorithm were the best and successfully applied for classification of different Baijiu vintages. A total of 14 differential compounds (belonging to fatty acid ethyl esters, alcohols, organic acids, and aldehydes) were identified, and used for evaluation of commercial Maotai-flavor Baijiu. Our results indicated that both volatiles and nonvolatiles contributed to the vintage differences. This study demonstrated that GC-MS and 1H NMR spectra combined with a data fusion strategy are practical for the classification of different vintages of Maotai-flavor Baijiu.


Subject(s)
Gas Chromatography-Mass Spectrometry , Gas Chromatography-Mass Spectrometry/methods , Flavoring Agents/chemistry , Proton Magnetic Resonance Spectroscopy/methods , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/analysis , Wine/analysis , Wine/classification , Magnetic Resonance Spectroscopy/methods
8.
Fungal Biol ; 128(4): 1859-1867, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38876538

ABSTRACT

Volatile organic compounds (VOCs) produced by yeasts can positively affect crops, acting as antifungals or biostimulants. In this study, Aureobasidium pullulans and Metschnikowia pulcherrima were evaluated as potential antagonists of Trichoderma spp., common fungal pathogen in mushroom cultivation. To assess the biocontrol ability and biostimulant properties of the selected yeast species, in vitro co-culture and VOCs exposure assays were conducted. In both assays, VOCs produced by Aureobasidium spp. showed the stronger antifungal activity with a growth inhibition up to 30 %. This result was further confirmed by the higher volatilome alcohol content revealed by solid phase microextraction-gas chromatography mass spectrometry (SPME/GC-MS). Overall, Aureobasidium strains can be potentially used as biocontrol agent in Pleorotus ostreatus and Cyclocybe cylindracea mycelial growth, without affecting their development as demonstrated by VOCs exposure assay and Fourier-transform infrared spectroscopy (FT-IR). Conversely, M. pulcherrima was characterized by a lower or absent antifungal properties and by a volatilome composition rich in isobutyl acetate, an ester often recognized as plant growth promoter. As confirmed by FT-IR, Lentinula mycelia exposed to M. pulcherrima VOCs showed a higher content of proteins and lipids, suggesting an improvement of some biochemical properties. Our study emphasizes that VOCs produced by specific yeast strains are potentially powerful alternative to synthetic fungicide in the vegetative growth of mushroom-forming fungi and also able to modify their biochemical composition.


Subject(s)
Agaricales , Gas Chromatography-Mass Spectrometry , Mycelium , Volatile Organic Compounds , Volatile Organic Compounds/pharmacology , Volatile Organic Compounds/metabolism , Volatile Organic Compounds/chemistry , Mycelium/growth & development , Mycelium/drug effects , Mycelium/chemistry , Agaricales/chemistry , Agaricales/growth & development , Agaricales/drug effects , Agaricales/metabolism , Antifungal Agents/pharmacology , Antifungal Agents/metabolism , Biological Control Agents/pharmacology , Biological Control Agents/chemistry , Metschnikowia/growth & development , Metschnikowia/drug effects , Metschnikowia/metabolism , Antibiosis , Aureobasidium , Trichoderma/growth & development , Trichoderma/chemistry , Trichoderma/metabolism , Solid Phase Microextraction
9.
Molecules ; 29(11)2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38893586

ABSTRACT

Hemerocallis L. possesses abundant germplasm resources and holds significant value in terms of ornamental, edible, and medicinal aspects. However, the quality characteristics vary significantly depending on different varieties. Selection of a high-quality variety with a characteristic aroma can increase the economic value of Hemerocallis flowers. The analytic hierarchy process (AHP) is an effective decision-making method for comparing and evaluating multiple characteristic dimensions. By applying AHP, the aromatic character of 60 varieties of Hemerocallis flowers were analyzed and evaluated in the present study. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) was employed to identify volatile components in Hemerocallis flowers. Thirteen volatile components were found to contribute to the aroma of Hemerocallis flowers, which helps in assessing their potential applications in essential oil, aromatherapy, and medical treatment. These components include 2-phenylethanol, geraniol, linalool, nonanal, decanal, (E)-ß-ocimene, α-farnesene, indole, nerolidol, 3-furanmethanol, 3-carene, benzaldehyde and benzenemethanol. The varieties with better aromatic potential can be selected from a large amount of data using an AHP model. This study provides a comprehensive understanding of the characteristics of the aroma components in Hemerocallis flowers, offers guidance for breeding, and enhances the economic value of Hemerocallis flowers.


Subject(s)
Flowers , Gas Chromatography-Mass Spectrometry , Solid Phase Microextraction , Volatile Organic Compounds , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Solid Phase Microextraction/methods , Flowers/chemistry , Odorants/analysis , Acyclic Monoterpenes/chemistry , Acyclic Monoterpenes/analysis , Oils, Volatile/chemistry , Oils, Volatile/analysis , Sesquiterpenes/analysis , Phenylethyl Alcohol/analogs & derivatives , Phenylethyl Alcohol/analysis , Phenylethyl Alcohol/chemistry , Alkenes , Indoles
10.
Food Res Int ; 188: 114454, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38823832

ABSTRACT

The Amadori rearrangement products are an important flavor precursor in the Maillard reaction. Its thermal decomposition products usually contribute good flavors in foods. Therefore, investigating the thermal breakdown of Amadori products is significant for understanding the flavor forming mechanism in the Maillard reaction. In this study, volatiles from thermal decomposition of Amadori products in cysteine and glucose Maillard reaction was investigated by a thermal desorption cryo-trapping system combined with gas chromatography-mass spectrometry (GC-MS). A total of 60 volatiles were detected and identified. Meanwhile, the forming mechanism of 2-methylthiophene, a major decomposition product, was also investigated by using density functional theory. Seventeen reactions, 12 transition states, energy barrier and rate constant of each reaction were finally obtained. Results reveal that it is more likely for Amadori products of cysteine and glucose to undergo decomposition under neutral or weakly alkaline conditions.


Subject(s)
Cysteine , Gas Chromatography-Mass Spectrometry , Glucose , Maillard Reaction , Volatile Organic Compounds , Cysteine/chemistry , Glucose/chemistry , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/analysis , Density Functional Theory , Hot Temperature
11.
Chemosphere ; 361: 142530, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38851511

ABSTRACT

Chiroptical sensing with real-time colorimetrical detection has been emerged as quantifiable properties, enantioselective responsiveness, and optical manipulation in environmental monitoring, food safety and other trace identification fields. However, the sensitivity of chiroptical sensing materials remains an immense challenge. Here, we report a dynamically crosslinking strategy to facilitate highly sensitive chiroptical sensing material. Chiral nematic cellulose nanocrystals (CNC) were co-assembled with amino acid by a two-step esterification, of which a precisely tunable helical pitch, a unique spiral conformation with hierarchical and numerous active sites in sensing performance could be trigged by dynamic covalent bond on amines. Such a CNC/amino acid chiral optics features an ultra-trace amount of 0.08 mg/m3 and a high sensitivity of 60 nm/(mg/m3) for formaldehyde gas at a molecule level detection, which is due to the three synergistic adsorption enhancement of dynamic covalent bonded interaction, hydrogen bonded interaction and van der Waals interaction. Meanwhile, an enhancement hierarchical adsorption of CNC/amino acid chiral materials can be readily representative to the precise helical pitch and colorimetrical switch for sensitive visualization reorganization.


Subject(s)
Cellulose , Nanoparticles , Volatile Organic Compounds , Cellulose/chemistry , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Nanoparticles/chemistry , Environmental Monitoring/methods , Amino Acids/analysis , Amino Acids/chemistry , Colorimetry/methods , Stereoisomerism , Formaldehyde/chemistry , Formaldehyde/analysis , Adsorption
12.
Chemosphere ; 361: 142551, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38852280

ABSTRACT

The fate of volatile organic compounds (VOC) vapors in the unsaturated zone is the basis for evaluating the natural attenuation potential and vapor intrusion risk. Microcosm and column experiments were conducted to study the effects chemical speciation and soil types/properties on the fate of petroleum VOCs in unsaturated zone. The biodegradation and total attenuation rates of the seven VOCs obtained by microcosm experiments in black soil and yellow earth were also generally higher than those in floodplain soil, lateritic red earth, and quartz sand. The VOC vapors in floodplain soil, lateritic red earth, and quartz sand showed slow total attenuation rates (<0.3 d-1). N-pentane, methylcyclopentane, and methylcyclohexane showed lower biodegradation rates than octane and three monoaromatic hydrocarbons. Volatilization into the atmosphere and biodegradation are two important natural attenuation paths for VOCs in unsaturated soil columns. The volatilization loss fractions of different volatile hydrocarbons in all five unsaturated soils were generally in the order: n-pentane (93.5%-97.8%) > methylcyclopentane (77.2%-85.5%) > methylcyclohexane (53.5%-69.2%) > benzene (17.1%-73.3%) > toluene (0-45.7%) > octane (1.9%-34.2%) > m-xylene (0-5.7%). The fractions by volatilization into the atmosphere of all seven hydrocarbons in quartz sand, lateritic red earth, and floodplain soil were close and higher compared to the yellow earth and black soil. Overall, this study illustrated the important roles chemical speciation and soil properties in determining the vapor-phase transport and natural attenuation of VOCs in the unsaturated zone.


Subject(s)
Biodegradation, Environmental , Petroleum , Soil Pollutants , Soil , Volatile Organic Compounds , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Petroleum/analysis , Soil/chemistry , Soil Pollutants/analysis , Soil Pollutants/chemistry , Adsorption , Volatilization , Pentanes/chemistry , Pentanes/analysis , Octanes/chemistry , Toluene/chemistry , Toluene/analysis , Benzene/analysis , Benzene/chemistry
13.
Sensors (Basel) ; 24(12)2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38931722

ABSTRACT

This study aimed to fabricate and characterize a novel colorimetric indicator designed to detect ammonia (NH3) and monitor meat freshness. The sensing platform was constructed using electrospun nanofibers made from polylactic acid (PLA), which were then impregnated with anthocyanins as a natural pH-sensitive dye, extracted from red cabbage. This research involved investigating the relationship between the various concentrations of anthocyanins and the colorimetric platform's efficiency when exposed to ammonia vapor. Scanning electron microscope (SEM) results were used to examine the morphology and structure of the nanofiber mats before and after the dip-coating process. The study also delved into the selectivity of the indicator when exposed to various volatile organic compounds (VOCs) and their stability under extreme humidity levels. Furthermore, the platform's sensitivity was evaluated as it encountered ammonia (NH3) in concentrations ranging from 1 to 100 ppm, with varying dye concentrations. The developed indicator demonstrated an exceptional detection limit of 1 ppm of MH3 within just 30 min, making it highly sensitive to subtle changes in gas concentration. The indicator proved effective in assessing meat freshness by detecting spoilage levels in beef over time. It reliably identified spoilage after 10 h and 7 days, corresponding to bacterial growth thresholds (107 CFU/mL), both at room temperature and in refrigerated environments, respectively. With its simple visual detection mechanism, the platform offered a straightforward and user-friendly solution for consumers and industry professionals alike to monitor packaged beef freshness, enhancing food safety and quality assurance.


Subject(s)
Ammonia , Colorimetry , Food Packaging , Red Meat , Colorimetry/methods , Food Packaging/methods , Ammonia/chemistry , Ammonia/analysis , Cattle , Red Meat/analysis , Red Meat/microbiology , Animals , Nanofibers/chemistry , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Polyesters/chemistry , Anthocyanins/chemistry , Meat/analysis , Meat/microbiology
14.
Environ Sci Technol ; 58(26): 11781-11790, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38877971

ABSTRACT

Synergistic control of nitrogen oxides (NOx) and nitrogen-containing volatile organic compounds (NVOCs) from industrial furnaces is necessary. Generally, the elimination of n-butylamine (n-B), a typical pollutant of NVOCs, requires a catalyst with sufficient redox ability. This process induces the production of nitrogen-containing byproducts (NO, NO2, N2O), leading to lower N2 selectivity of NH3 selective catalytic reduction of NOx (NH3-SCR). Here, synergistic catalytic removal of NOx and n-B via spatially separated cooperative sites was originally demonstrated. Specifically, titania nanotubes supported CuOx-CeO2 (CuCe-TiO2 NTs) catalysts with spatially separated cooperative sites were creatively developed, which showed a broader active temperature window from 180 to 340 °C, with over 90% NOx conversion, 85% n-B conversion, and 90% N2 selectivity. A synergistic effect of the Cu and Ce sites was found. The catalytic oxidation of n-B mainly occurred at the Cu sites inside the tube, which ensured the regular occurrence of the NH3-SCR reaction on the outer Ce sites under the matching temperature window. In addition, the n-B oxidation would produce abundant intermediate NH2*, which could act as an extra reductant to promote NH3-SCR. Meanwhile, NH3-SCR could simultaneously remove the possible NOx byproducts of n-B decomposition. This novel strategy of constructing cooperative sites provides a distinct pathway for promoting the synergistic removal of n-B and NOx.


Subject(s)
Nitrogen Oxides , Catalysis , Nitrogen Oxides/chemistry , Volatile Organic Compounds/chemistry , Oxidation-Reduction
15.
Environ Sci Technol ; 58(26): 11760-11770, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38900969

ABSTRACT

Oxygenated volatile organic compounds (OVOCs), emitted in large quantities by the chemical industry, are a major contributor to the formation of ozone and subsequent particulate matter. For the efficient catalytic oxidation of OVOCs, the challenges of molecular activation and intermediate inhibition remain. The construction of bifunctional active sites with specific structures offers a promising way to overcome these problems. Here, the Pd@Layered-CoOx/MFI bifunctional catalyst with core-shell active sites was rationally fabricated though a two-step ligand pyrolysis method, which exhibits a superb oxidation efficiency toward ethyl acetate (EA). Over this, 13.4% of EA (1000 ppm) can be oxidized at just 140 °C with a reaction rate of 13.85 mmol·gPd-1·s-1, around 176.7 times higher than that of the conventional Pd-CoOx/MFI catalyst. The electronic coupling of the Pd-Co pair promotes the electron back-donation from Pd nanoparticles to the layered CoOx shell and facilitates the formation of Pd2+ species, which greatly enhances the adsorption and activation of the electron-rich C═O bond of the EA molecules. In addition, the synergy of these core-shell Pd@Layered-CoOx sites accelerates the activation and transformation of *O species, which inhibit the formation of acetaldehyde and ethanol byproducts, ensuring the rapid total oxidation of EA molecules via the Mars-van Krevelen mechanism. This work established a solid foundation for exploring robust bifunctional catalysts for deep OVOC purification.


Subject(s)
Oxidation-Reduction , Catalysis , Palladium/chemistry , Volatile Organic Compounds/chemistry , Acetates/chemistry
16.
Adv Appl Microbiol ; 127: 1-43, 2024.
Article in English | MEDLINE | ID: mdl-38763526

ABSTRACT

In recent years, the study of volatile compounds has sparked interest due to their implications in signaling and the enormous variety of bioactive properties attributed to them. Despite the absence of analysis methods standardization, there are a multitude of tools and databases that allow the identification and quantification of volatile compounds. These compounds are chemically heterogeneous and their diverse properties are exploited by various fields such as cosmetics, the food industry, agriculture and medicine, some of which will be discussed here. In virtue of volatile compounds being ubiquitous and fast chemical messengers, these molecules mediate a large number of interspecific and intraspecific interactions, which are key at an ecological level to maintaining the balance and correct functioning of ecosystems. This review briefly summarized the role of volatile compounds in inter- and intra-specific relationships as well as industrial applications associated with the use of these compounds that is emerging as a promising field of study.


Subject(s)
Microbiota , Volatile Organic Compounds , Humans , Ecosystem , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Electronic Nose , Industry
17.
Molecules ; 29(10)2024 May 08.
Article in English | MEDLINE | ID: mdl-38792057

ABSTRACT

Coleus scutellarioides (L.) Benth. is a globally spread species, known for its characteristic spectacularly colorful leaves of decorative value. Thanks to its rich chemical composition, the plant is used in ethnopharmacology, and it is also regarded as having high medicinal potential. The application of in vitro cultures enables the acquisition of homogeneous certified material of high quality. Additionally, excluding the effect of biotic and abiotic factors on the plants is a way to fully recognize the influence of phytohormones on the plant morphology and the biosynthetic pathways of compound production. The best way to grow C. scutellarioides "Electric Lime" under in vitro conditions is to use the basic MS medium (Murashige and Skoog medium), enriched with naphthyl-1-acetic acid at a concentration of 0.5 mg dm-3. The analysis of volatile compounds demonstrated that the content of volatile compounds in the plants cultivated under in vivo conditions was expressed at a level of 2848.59 µg g-1, whereas in the plants bred in vitro without supplementation with phytohormones, the level was 8191.47 µg g-1. The highest content was noted for copaene, α-pinene, 1-octene-3-ol, α-selinene, sabinen, γ- and δ-cadinene, 3-octanol, and ß-pinene. Aroma profiling revealed a lack of boranyl acetate, 2-hexenal, and 2-hexen-1-ol in the plants cultivated under in vivo conditions. Differences were found in the volatile composition between plants bred in vivo and in vitro, with the most significant recorded for the contents of 1-octen-3-ol and 3-octanol. The addition of plant growth regulators into the basic medium under in vitro conditions affected the percentage ratio and contents of specific compounds in plant tissues. The most intense biosynthesis of volatile compounds took place in the plants cultivated on the medium enriched with NAA at 10,579.11 µg g-1, whereas the least intense was noted for plants cultivated on the medium supplemented with BA, where it was recorded at the level of 5610.02 µg g-1. So far, there has been no research published which would pertain to the profiling of volatile compounds performed using the SPME (solid-phase microextraction) technique. Moreover, the very few studies conducted on the chemical composition of these compounds do not mention the specific variety of C. scutellarioides under analysis.


Subject(s)
Volatile Organic Compounds , Volatile Organic Compounds/metabolism , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/analysis , Plant Growth Regulators/pharmacology , Plant Leaves/metabolism , Plant Leaves/growth & development , Plant Leaves/chemistry
18.
Molecules ; 29(10)2024 May 14.
Article in English | MEDLINE | ID: mdl-38792158

ABSTRACT

This work is focused on the characterization of the composition of a CO2 supercritical fluid extract of Aquilaria sinensis (Chinese agarwood) collected in the Dongguan area (China) and infected by mechanical methods. The constituents of this extract were analyzed by gas chromatography-mass spectrometry (GC-MS) and quantified accurately by gas chromatography with a flame ionization detector (GC-FID), using an internal reference and predicted response factors. Since a significant number of components of this extract remained non-identified after the initial GC-MS analysis of the whole extract, its fractionation by chromatography on silica gel helped to characterize several additional constituents by isolation and structural analysis by NMR spectroscopy. The main components are the classical agarwood chromones (Flindersia chromone and its mono-, di-, and trimethoxylated analogues (respectively, 11.01% and 0.11-4.02%) along with sesquiterpenic constituents typically found in agarwood essential oils, like baimuxinal (1.90%) and kusunol (1.24%), as well as less common selinane dialdehydes (1.58-2.27%) recently described in the literature. Moreover, the structure and stereochemistry of a new sesquiterpenic alcohol, 14ß,15ß-dimethyl-7αH-eremophila-9,11-dien-8ß-ol (0.67%), was determined unambiguously by the combination of structural analysis (NMR, MS), hemisynthesis, and total synthesis, leading to dihydrokaranone and a neopetasane epimer.


Subject(s)
Carbon Dioxide , Chromatography, Supercritical Fluid , Gas Chromatography-Mass Spectrometry , Thymelaeaceae , Thymelaeaceae/chemistry , Chromatography, Supercritical Fluid/methods , Carbon Dioxide/chemistry , Plant Extracts/chemistry , Magnetic Resonance Spectroscopy/methods , Oils, Volatile/chemistry , Oils, Volatile/analysis , Volatile Organic Compounds/analysis , Volatile Organic Compounds/chemistry , Molecular Structure , East Asian People
19.
J Agric Food Chem ; 72(23): 13273-13283, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38805030

ABSTRACT

Freeze-dried ginger (Zingiber officinale) is renowned for its high quality, but it is expensive. As an alternative, spray drying can be explored for producing ginger powder. However, sugar rich feed solutions can lead to stickiness development during the process. Adding carrier materials increases costs and labeling. Accordingly, a split-stream spray-drying process was developed, where ginger fibers in their natural composition were reintroduced as a carrier material into the spray-drying process. The inlet and outlet temperatures were set at 220 and 80 °C, respectively, for optimal aroma retention. Using a stir bar sorptive extraction-gas chromatography-mass spectrometry-olfactometry, the results revealed that reintegrating ginger fibers significantly increased the concentration of eight key odorants. Although freeze-dried ginger retains more aroma, the total concentration of twenty-seven odorants in the developed spray-dried ginger was 1.9 times higher compared to frozen ginger.


Subject(s)
Gas Chromatography-Mass Spectrometry , Odorants , Powders , Zingiber officinale , Zingiber officinale/chemistry , Odorants/analysis , Powders/chemistry , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/analysis , Olfactometry , Spray Drying
20.
J Agric Food Chem ; 72(23): 12975-12987, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38807047

ABSTRACT

This study discovered the impact of high-tunnel (i.e., unheated greenhouse) and open-field production on two industrial hemp cultivars (SB1 and CJ2) over their yield parameters, cannabinoid development, and volatile profiles. Development of neutral cannabinoids (CBD, THC, and CBC), acidic cannabinoids (CBDA, THCA, and CBCA), and total cannabinoids during floral maturation were investigated. The volatile profiles of hemp flowers were holistically compared via HS-SPME-GC/MS. Findings indicated a high tunnel as an efficient practice for achieving greater total weight, stem number, and caliper, especially in the SB1 cultivar. Harvesting high-tunnel-grown SB1 cultivars during early flower maturation could obtain a high CBD yield while complying with THC regulations. Considering the volatile profiles, hemp flowers mainly consisted of mono- and sesquiterpenoids, as well as oxygenated mono- and sesquiterpenoids. Volatile analysis revealed the substantial impact of cultivars on the volatile profile compared to the production systems.


Subject(s)
Cannabinoids , Cannabis , Gas Chromatography-Mass Spectrometry , Inflorescence , Volatile Organic Compounds , Cannabis/chemistry , Cannabis/growth & development , Cannabis/metabolism , Cannabinoids/analysis , Cannabinoids/metabolism , Volatile Organic Compounds/chemistry , Volatile Organic Compounds/metabolism , Volatile Organic Compounds/analysis , Inflorescence/chemistry , Inflorescence/growth & development , Inflorescence/metabolism , Flowers/chemistry , Flowers/growth & development , Flowers/metabolism , Plant Extracts/chemistry , Plant Extracts/metabolism
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