Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.924
Filtrar
1.
Bioresour Technol ; 300: 122705, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31926472

RESUMO

Adsorption is an efficient and low-cost technology used to purify volatile organic compounds (VOCs). In the current study, novel microbial adsorbents were synthesized using cells of lyophilized fungi (Ophiostoma stenoceras LLC) or bacteria (Pseudomonas veronii ZW) that were modified by aminomethylation. Based on the adsorption performance and structural characterization results, the modified fungal biosorbent was the best. Its maximum adsorption capacities for ethyl acetate, α-pinene, and n-hexane were 620, 454, and 374 mg·g-1, respectively, which were much higher than those of other synthesized biosorbents. The specific surface area of the fungal biosorbent was 20 m2·g-1, and most of the components were hydrocarbon compounds and polysaccharides. The VOC adsorption process on these synthesized biosorbents was in accordance with the Langmuir isothermal model and the pseudo-first-order kinetic model, thereby suggesting that physical adsorption was the dominant mechanism. The fungal biosorbent could be used for five consecutive VOC sorption-desorption cycles without any obvious decrease in adsorption capacity.


Assuntos
Compostos Orgânicos Voláteis , Poluentes Químicos da Água , Adsorção , Biomassa , Fungos , Concentração de Íons de Hidrogênio , Cinética
2.
J Agric Food Chem ; 68(6): 1678-1683, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31957422

RESUMO

During submerged cultivation, the edible basidiomycete Fomitopsis betulina (previously Piptoporus betulinus) developed a fruity odor, strongly reminding of pineapple. Olfactometric analysis showed that this impression was mainly caused by the two (5E/Z,7E,9)-decatrien-2-ones. At the time of maximum concentration on the 5th day, the (5E/5Z)-ratio was 94:6. Three hypotheses were experimentally examined to shed light onto the genesis of the uncommon volatiles: first, an indirect effect of agro-industrial side-streams, such as cabbage cuttings, supporting good growth; second, an unsaturated odd-numbered fatty acid precursor; and third, a polyketide-like pathway. In the presence of 1-13C- or 2-13C-acetate up to five acetates were incorporated into the molecular ions of the C10-body. Addition of 1-13C-pyruvate or 1-13C-lactate did not confirm an odd-numbered starter of the polyketide chain. None of the methylketones was found in pineapple or any other food before.


Assuntos
Coriolaceae/química , Odorantes/análise , Compostos Orgânicos Voláteis/química , Acetatos/análise , Isótopos de Carbono/análise , Coriolaceae/crescimento & desenvolvimento , Coriolaceae/metabolismo , Cetonas/química , Compostos Orgânicos Voláteis/metabolismo
3.
J Agric Food Chem ; 68(6): 1666-1677, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31957444

RESUMO

A potent unpleasant aroma presenting a pickle-like off-odor in Moutai-aroma type Baijiu was studied by comparative aroma extract dilution analysis (AEDA). Two Moutai-aroma type Baijiu samples, one having no off-odor (A) and the other one presenting pickle-like off-odor (B), were selected for chemical analysis and sensory evaluation. The aroma compounds were isolated by headspace solid-phase microextraction and liquid-liquid extraction. AEDA, quantitative analysis, and odor activity value calculation were performed in both the A and B samples. The main differences between the two samples were obtained for 12 compounds, presenting significantly higher concentrations in the off-odor sample. A total of 30 Moutai-aroma type Baijiu samples having different intensities of pickle-like sensory defect were analyzed to confirm the differences. An aroma addition test indicated that the 12 compounds with higher concentrations contributed to the pickle-like off-odor when spiked into sample A. Finally, a triangle test involving omission of the aroma compounds from the spiked A sample proved that 2-methyl-3-furanthiol, methional, methyl 2-methyl-3-furyl disulfide, dimethyl trisulfide, 2-furfurylthiol, methanethiol, dimethyl disulfide, and bis(2-methyl-3-furyl)disulfide with higher concentrations were generally responsible for the pickle-like off-odor in Moutai-aroma type Baijiu.


Assuntos
Aromatizantes/análise , Odorantes/análise , Vinho/análise , Aromatizantes/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Olfato , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação
4.
J Agric Food Chem ; 68(1): 258-266, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31825219

RESUMO

Screening the volatiles of cempedak [Artocarpus integer (Thunb.) Merr.] pulp for odor-active compounds by aroma extract dilution analysis and gas chromatography (GC)-olfactometry of static headspace samples revealed a total of 55 odorants, among which 47 were identified. Using stable isotopically substituted odorants as internal standards, these compounds were quantitated by GC-mass spectrometry, and odor activity values (OAVs) were calculated as ratios of the natural concentrations in cempedak pulp to the orthonasal odor detection thresholds. An aroma reconstitution model based on the 41 compounds with OAVs >1 in their natural concentrations successfully mimicked the characteristic aroma of cempedak pulp including the pronounced sulfury, oniony note which is intense in cempedak pulp but absent in jackfruit pulp. Further sensory tests finally showed that 2-(methylsulfanyl)propane, 2-(methylsulfanyl)butane, and 2-(methylsulfanyl)pentane are the key compounds responsible for this unique aroma note in cempedak pulp and vitally contribute to the aroma difference between cempedak pulp and jackfruit pulp.


Assuntos
Artocarpus/química , Odorantes/análise , Compostos Orgânicos Voláteis/química , Aromatizantes/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Estrutura Molecular , Olfatometria , Olfato
5.
J Agric Food Chem ; 68(1): 279-291, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31802659

RESUMO

This study aimed to identify the key aroma-active volatiles in cranberry wines through three vinification methods (White, Red and Thermo) using GC-MS/O to identify the important aroma compounds. A total of 70 compounds were detected, with 67 in wines and 61 in juices. The esters was the most diversified class, while alcohols and acids were the most abundant, especially 3-methylbutanol, methylbutyric acid, and benzoic acid. The volatile profiles of cranberry wines are distinctive from their source juices. Most alcohols, esters, and acids are fermentation-derived, while terpenes, phenols, aldehydes and ketones are varietal. The Red vinification retained the most varietal volatiles from the must, while the White and Thermo vinifications produced more volatiles during fermentation. Thermovinification reduced the yield of benzoic acid and its derivatives after fermentation. Olfactory analysis identified 47 aroma-active compounds, among which 41 were considered as the major aroma contributors (ethyl benzoate had the highest modified detection frequency).


Assuntos
Aromatizantes/química , Sucos de Frutas e Vegetais/análise , Vaccinium macrocarpon/química , Compostos Orgânicos Voláteis/química , Vinho/análise , Fermentação , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise
6.
J Chem Ecol ; 46(1): 30-39, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31808075

RESUMO

Cerambycid beetles of the subfamily Lamiinae use male-produced aggregation-sex pheromones that are attractive to both sexes. Terpenoid pheromones have been identified from species in the tribes Acanthoderini and Acanthocinini native to North and South America, comprised of (E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone), the structurally related 6-methylhept-5-en-2-one (sulcatone), and/or specific enantiomers or nonracemic ratios of enantiomers of the related compounds (E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol), its acetate ester, (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate), and 6-methylhept-5-en-2-ol (sulcatol). Here, we present new information about the chemical ecology of six acanthoderine and acanthocinine species native to the eastern USA. The pheromone of Astyleiopus variegatus (Haldeman) previously was identified as a blend of (S)-fuscumol and (S)-fuscumol acetate, and we report here that geranylacetone is a synergistic component. Males of Aegomorphus modestus (Gyllenhal), Lepturges angulatus (LeConte), and Lepturges confluens (Haldeman) were found to produce similar blends composed of the enantiomers of fuscumol acetate and geranylacetone, whereas males of Astylidius parvus (LeConte) and Sternidius alpha (Say) produced both enantiomers of fuscumol together with (R)-fuscumol acetate and geranylacetone. Field experiments with synthesized chemicals revealed that species with similar pheromone composition nevertheless differed in their responses to individual components, and to various blends of components, and in how attraction was influenced by chemicals that were pheromone components of other species. Sulcatone and/or sulcatol antagonized attraction of some species to pheromones of the geranylacetone class, suggesting that there is an adaptive advantage in an ability to detect these heterospecific compounds, such as in avoiding cross attraction to other cerambycid species, as yet unknown, that use pheromones composed of both chemical classes.


Assuntos
Besouros/química , Feromônios/química , Animais , Besouros/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Masculino , Feromônios/isolamento & purificação , Feromônios/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Especificidade da Espécie , Estereoisomerismo , Terpenos/química , Terpenos/isolamento & purificação , Terpenos/farmacologia , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Compostos Orgânicos Voláteis/farmacologia
7.
J Sci Food Agric ; 100(3): 978-985, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31617213

RESUMO

BACKGROUND: Sorghum grain is rich in phenolic compounds and has the potential to be developed into functional beverages such as sorghum grain tea, in which the health benefits and flavour are the important quality attributes to be considered in tea product development. Therefore, this study investigated the effect of grain tea processing steps on the phenolic contents, antioxidant activity and aroma profile (volatile compounds) of MR-Buster (red-coloured) and Shawaya Short Black 1 (black-coloured) sorghum and the results compared with those for our previously reported Liberty (white-coloured) sorghum. RESULTS: Tea processing had significant impacts on sorghum polyphenols and volatile compounds, but the effect and level varied among sorghum varieties. The phenolic contents and antioxidant activity in these three sorghum varieties were consistent in both raw grain and grain tea samples and in the order Shawaya Short Black 1 > MR-Buster > Liberty. However, the volatile profiles (both individual and grouped volatiles) were significantly different between sorghum varieties, and the abundance and diversity of the volatile compounds of the tea samples were in the order Liberty > MR-Buster > Shawaya Short Black 1. CONCLUSIONS: Black-coloured sorghum with high phenolic content and antioxidant activity is more suitable for making sorghum tea considering the health benefits. In terms of the aroma intensity and diversity, white-coloured sorghum could be the ideal material. However, future study is needed to determine the key volatile compounds that positively contribute to the aroma. This work provides important insights into the selection of grain materials for sorghum grain tea production. © 2019 Society of Chemical Industry.


Assuntos
Antioxidantes/química , Bebidas/análise , Fenóis/química , Extratos Vegetais/química , Sorghum/química , Compostos Orgânicos Voláteis/química , Manipulação de Alimentos , Sorghum/classificação
8.
J Sci Food Agric ; 100(3): 1038-1047, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31650558

RESUMO

BACKGROUND: The aquafeed sector has been replacing conventional dietary ingredients with more economic and eco-friendly ingredients. Insects embody a promising alternative as a result of being highly nutritious and showing traits leading to a circular bioeconomy. Atlantic salmon (Salmo salar L.) at the sea-water stage were fed diets with a partial or complete substitution of fishmeal with meal of Hermetia illucens larvae reared on a media containing Ascophyllum nodosum mixed with organic wastes (60:40). The present study aimed to assess the quality of fillets by characterizing its physico-chemical traits with conventional and innovative methods, such as the proton transfer reaction-time of flight-mass spectrometer technique, allowing the analysis of samples at room temperature. Finally, steamed fillets underwent a consumer test to investigate the liking of consumers and their intention of re-consumption. RESULTS: The main findings showed that a complete dietary substitution of fishmeal with H. illucens larvae meal did not impair the physico-chemical quality of A. salmon fillets. Notably, neutral n-3 polyunsaturated fatty acids (PUFA) slightly but significantly increased in the fillets of A. salmon fed H. illucens, also as a result of the additional fish oil present in the diets containing insect. The volatile organic profile was not altered by the different diets. The consumer-liking test revealed that Italian consumers appreciated the tested salmon irrespective of the administered feed. CONCLUSION: Tailoring the insect fatty acid profile by rearing the larvae on a PUFA-rich substrate, coupled with a dietary modulation of the oily source, can successfully maintain or even increase the cardioprotective characteristics of fillets. © 2019 Society of Chemical Industry.


Assuntos
Ração Animal/análise , Larva/química , Salmo salar/metabolismo , Compostos Orgânicos Voláteis/análise , Animais , Dieta/veterinária , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/metabolismo , Pesqueiros , Larva/metabolismo , Carne/análise , Salmo salar/crescimento & desenvolvimento , Simuliidae/química , Simuliidae/metabolismo , Compostos Orgânicos Voláteis/metabolismo
9.
J Sci Food Agric ; 100(3): 1328-1335, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31743449

RESUMO

BACKGROUND: In recent years, mini-watermelons have increased in popularity. To maintain production and quality standards, various agronomic techniques have been applied. For the Cucurbitaceae family, grafting technique has been used to improve resistance to abiotic stresses, crop productivity and fruit qualitative characteristics. There is some previous literature on this matter, but no information on the influence of grafting on the aroma compounds of mini-watermelons is available. Hence, our research aimed to evaluate the effect of some rootstocks, which were selected on the basis of their tolerance to pathogens, on the quality of mini-watermelons, with particular attention to the volatile aroma compounds. RESULTS: Volatile aroma compounds were analysed using solid-phase microextraction-gas chromatography-mass spectrometry. The most represented compounds were C6 and C9 aldehydes and alcohols, which characterize the fruit aroma of the Cucurbitaceae family: (Z)-2-nonenal, (E,Z)-2,6-nonadienal, (Z)-3-nonen-1-ol and (Z,Z)-3,6-nonadien-1-ol were prevalent. Quantitative differences resulted in relation to the various selected rootstocks. Among these, the RS841 rootstock was found to be the most suitable for maintaining yield, quality parameters, sensory characteristics and volatile aroma compounds of mini-watermelon fruits. CONCLUSIONS: The results highlighted that the rootstock, as for other Cucurbitaceae varieties, influences fruit quality and plant yield also for the mini-water melon; the results show the importance of screening for rootstock/scion combinations in order to select a graft able to provide resistance to abiotic stresses, and at the same time improve yield and fruit quality. © 2019 Society of Chemical Industry.


Assuntos
Citrullus/química , Produção Agrícola/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/química , Álcoois/análise , Aldeídos/análise , Citrullus/crescimento & desenvolvimento , Frutas/química , Frutas/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas
10.
J Chem Ecol ; 46(1): 1-9, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31840210

RESUMO

The rice stalk stink bug, Tibraca limbativentris, is an important rice pest in Brazil with a high invasive potential for Mexico and the USA. The sex pheromone of this species was previously identified as a combination of two stereoisomers of 1,10-bisaboladien-3-ol (zingiberenol), but the absolute configurations of these sesquiterpenes were not determined, neither were their effect(s) on T. limbativentris behavior evaluated. In this study, using two chiral columns, we compared retention times of the two natural 1,10-bisaboladien-3-ol stereoisomers from air-entrainment samples of male T. limbativentris with those of synthetic stereoisomers of 1,10-bisaboladien-3-ol. The results showed that T. limbativentris males produce (3S,6S,7R)-1,10-bisaboladien-3-ol (1) and (3R,6S,7R)-1,10-bisaboladien-3-ol (5) as their sex pheromone. Two new minor, male-specific components were also identified as cis and trans isomers of 2,10-bisaboladien-1-ol (sesquipiperitol). Y-tube olfactometer bioassays showed that the major (3S,6S,7R) isomer 1 was essential for attraction of T. limbativentris females, but the minor (3R,6S,7R) isomer 2 was not, nor did it show synergistic/antagonistic effects when added to the major isomer. The (1S,6S,7R) and (1R,6S,7R) stereoisomers of sesquipepiritol also attracted T. limbativentris females.


Assuntos
Comportamento Animal/efeitos dos fármacos , Heterópteros/química , Sesquiterpenos/análise , Atrativos Sexuais/farmacologia , Animais , Cromatografia Gasosa , Feminino , Heterópteros/metabolismo , Masculino , Sesquiterpenos/farmacologia , Atrativos Sexuais/análise , Estereoisomerismo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
11.
Bioresour Technol ; 297: 122469, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31787517

RESUMO

This work dealt with the determination of the suitability of sorption of Volatile Organic Compounds (VOCs) on biochars prepared from neem, sugarcane and bamboo feedstocks. Six different VOCs namely benzene, toluene, methyl chloride, xylene, chloroform and carbon tetrachloride were used in a laboratory-scale set-up on non-activated biochars prepared via slow pyrolysis (350-550 °C). Although all the chars showed considerable sorption but amongst them N3 (neem-based biochar) showed the maximum removal efficiency (65.5 mg g-1 for toluene). Variation in pyrolysis temperature and feedstock type showed significant change in the porosity and specific surface area of the biochar, which is favorable for VOC sorption efficiency. With higher surface area and contact time, the sorption capacity of char enhanced. However, the extent of sorption capacity of biochars differed with changing VOC type. Pseudo-Second-Order model fitted well with the results obtained from VOC sorption kinetics.


Assuntos
Compostos Orgânicos Voláteis , Adsorção , Carvão Vegetal , Tolueno
12.
J Agric Food Chem ; 68(1): 267-278, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31833769

RESUMO

Gas chromatography-olfactometry coupled with sensory analysis and partial least-squares regression (PLSR) analysis led to the identification of the odorants responsible for the different flavors of four yeast extracts. Sensory analysis showed that LA00L had an intense sulfurous attribute, and LA00 was characterized by fatty and green notes, FA31 exhibited the floral odor, while KA02 had strong phenolic, animal, fermented, roasted, and caramellic notes. A total of 37 key aroma compounds with odor activity values greater than 1 were determined. 2,4-Di-tert-butylphenol and methional were the most potent aroma compounds. In addition, the key aroma compounds in LA00L were nonanal, dimethyl disulfide, and γ-decalactone. Octanal, dimethyl disulfide, and benzeneacetaldehyde were the key aroma compounds in LA00. In FA31, styrene, benzeneacetaldehyde, and acetophenone were the key aroma compounds, while indole, 2-methoxyphenol, benzeneacetaldehyde, and p-cresol contributed significantly to the aroma of KA02. PLSR showed that p-cresol and indole were significantly responsible for the phenolic and animal notes inducing the off-flavor (yeasty odor) of yeasty extracts. More significantly, indole was first reported to have an important effect on yeasty odor.


Assuntos
Aromatizantes/química , Odorantes/análise , Saccharomyces cerevisiae/química , Compostos Orgânicos Voláteis/química , Adulto , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Pessoa de Meia-Idade , Olfato , Adulto Jovem
13.
J Sci Food Agric ; 100(3): 945-952, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31489633

RESUMO

BACKGROUND: Watermelon is appreciated for its nutritional properties and for its flavor. Among the flavor-active compounds that it contains, volatiles play a key role being responsible for aroma. Recent breeding activity has led to the release of mini-watermelons with reduced fruit weight. This paper reports on the characterization of aroma profiles of 'Rugby' and 'Cuoredolce®' novel mini-watermelon cultivars at the ripening stage. The main volatiles were identified and quantified using headspace solid-phase microextraction gas-chromatography mass spectrometry (HS-SPME-GC-MS), and their concentrations were correlated with the E-nose profile. The potential contribution of volatile compounds to the fruit aroma was evaluated by computing the odor activity values (OAV). RESULTS: Twenty main volatile compounds were identified: aldehydes (9), alcohols (4), ketones (2), and terpenes and terpenoids (5). C-9 aldehydes and alcohols were the prevalent compounds. The two cultivars differed in precocity, with 'Rugby' being riper from the early stage considered. Many apocarotenoids with desirable olfactory notes were detected in the volatile profile of 'Rugby'. Four e-nose sensors' signals significantly changed with variety and ripening stage: W1W and W2W were positively correlated and W6S was negatively correlated with all identified volatiles, while W3S showed a negative correlation with 6-methyl-5-hepten-2-one, the major lycopene catabolite. CONCLUSIONS: The aroma profiles described here contribute to the characterization of 'Cuoredolce®' and 'Rugby' mini-watermelon cultivars. Electronic-nose measurement was able to discriminate between cultivars and, to a lesser extent, among ripening stages. © 2019 Society of Chemical Industry.


Assuntos
Citrullus/química , Frutas/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Citrullus/classificação , Citrullus/crescimento & desenvolvimento , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação
14.
J Forensic Sci ; 65(1): 134-143, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31479524

RESUMO

Volatile organic compounds (VOCs) are by-products of cadaveric decomposition and are responsible for the odor associated with decomposing remains. The direct link between VOC production and individual postmortem microbes has not been well characterized experimentally. The purpose of this study was to profile VOCs released from three postmortem bacterial isolates (Bacillus subtilis, Ignatzschineria indica, I. ureiclastica) using solid-phase microextraction arrow (SPME Arrow) and gas chromatography-mass spectrometry (GC-MS). Species were inoculated in headspace vials on Standard Nutrient Agar and monitored over 5 days at 24°C. Each species exhibited a different VOC profile that included common decomposition VOCs. VOCs exhibited upward or downward temporal trends over time. Ignatzschineria indica produced a large amount of dimethyldisulfide. Other compounds of interest included alcohols, aldehydes, aromatics, and ketones. This provides foundational data to link decomposition odor with specific postmortem microbes to improve understanding of underlying mechanisms for decomposition VOC production.


Assuntos
Bacillus subtilis/metabolismo , Gammaproteobacteria/metabolismo , Mudanças Depois da Morte , Compostos Orgânicos Voláteis/metabolismo , Animais , Medicina Legal , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Suínos
15.
J Chem Ecol ; 46(1): 76-83, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31845135

RESUMO

Multiple species of phytophagous insects may co-occur on a plant and while plants can defend themselves from insect herbivory, plant responses to damage by different species and feeding guilds of insects may be asymmetric. Plants can trigger specific responses to elicitors/effectors in insect secretions altering herbivore performance. Recently, maize chitinases present in fall armyworm (FAW, Spodoptera frugiperda) frass were shown to act as effectors suppressing caterpillar-induced defenses in maize while increasing caterpillar performance. We investigated the effect of frass chitinase-mediated suppression of herbivore defenses in maize on the performance and preference of a subsequent insect herbivore from a different feeding guild, corn leaf aphid (Rhopalosiphum maidis). Aphid performance was highest on plants with FAW damage without frass chitinases compared to damaged plants with frass chitinases or undamaged plants. Plant exposure to frass chitinases post FAW damage also altered the production of herbivore-induced volatile compounds compared to damaged, buffer-treated plants. However, aphid preference to damaged, frass chitinase-treated plants was not different from damaged, buffer-treated plants or undamaged plants. This study suggests that frass effector-mediated alteration of plant defenses affects insect herbivores asymmetrically; while it enhances the performance of caterpillars, it suppresses the performance of subsequent herbivores from a different feeding guild.


Assuntos
Afídeos/fisiologia , Herbivoria/fisiologia , Zea mays/química , Animais , Afídeos/crescimento & desenvolvimento , Quitinases/metabolismo , Quitinases/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Larva/fisiologia , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Spodoptera/fisiologia , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Zea mays/metabolismo
16.
J Chem Ecol ; 46(1): 99-113, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31845136

RESUMO

Goat herding is an important tool in the ecologically sound management of Mediterranean shrublands and woodlands, although effective levels of woody biomass removal by the goats is neither guaranteed nor easy to predict. Preliminary observations indicated that one reason for this may be poor understanding of plant-herbivore interactions that operate intraspecifically at the local spatial scale. We asked, whether goats show intraspecific preferences among neighboring plants when foraging a small local population of Pistacia lentiscus, a dominant tall shrub. First, we characterized and quantified the profile of stored and emitted volatile organic compounds (VOCs) and the PEG-binding capacity of tannins (a proxy for protein binding capacity) in the foliage of P. lentiscus shrubs, sampled within an area of 0.9 ha. We then tested goat preference between pairs of these shrubs that differed in chemical composition. Almost all sampled P. lentiscus shrubs were allocated to one of two distinct VOC chemotypes: one dominated by germacrene D and limonene (designated chemotype L) and the other by germacrene D and α-pinene (chemotype P). In contrast, continuous moderate variability was found in the binding capacity of tannins in the foliage. Goats showed preference for shrubs of chemotype L over those of chemotype P, and their preference was negatively correlated with the binding capacity of tannins. Possible influences of VOCs on goat preference that may explain the observed patterns are discussed in the light of possible context-dependent interpretation of plant VOC signals by large mammalian herbivores.


Assuntos
Herbivoria/efeitos dos fármacos , Pistacia/química , Taninos/farmacologia , Compostos Orgânicos Voláteis/farmacologia , Animais , Cromatografia Gasosa-Espectrometria de Massas , Cabras/fisiologia , Modelos Lineares , Pistacia/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Análise de Componente Principal , Taninos/análise , Taninos/química , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
17.
Chemosphere ; 240: 124908, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726596

RESUMO

Organosilicon compounds are the most undesirable compounds for the energy recovery of biogas. These compounds are still resistant to biodegradation when biotechnologies are considered for biogas purification. Herein we isolated 52 bacterial species from anaerobic batch enrichment cultures (BEC) saturated with D4 and from an anaerobic lab-scale biotrickling filter (BTF) fed with a gas flow containing D4 as unique carbon source. Among those Methylibium sp. and Pseudomonas aeruginosa showed the highest capacity to remove D4 (53.04% ±â€¯0.03 and 24.42% ±â€¯0.02, respectively). Contrarily, co-culture evaluation treatment for the biodegradation of siloxanes together with volatile organic compounds removed a lower concentration of D4 compared to toluene and limonene, which were completely removed. Remarkably, the siloxane D5 proved to be more biodegradable than D4. Substrates removal values achieved by Methylibium sp. suggested that this bacterial isolate could be used in biological removal technologies of siloxanes.


Assuntos
Biocombustíveis/análise , Reatores Biológicos/microbiologia , Burkholderiales/crescimento & desenvolvimento , Compostos de Organossilício/análise , Compostos Orgânicos Voláteis/análise , Anaerobiose , Biodegradação Ambiental , Purificação da Água/métodos
18.
Food Chem ; 305: 125480, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31522125

RESUMO

Milk samples from 1264 cows in 85 farms were authenticated for different farming-systems using a 10-fold cross-validated linear-discriminant-analysis using Fourier-transform infrared spectra (FTIRS) and gas-chromatographic fatty-acid (FA) profiles. FTIRS gave correct classification greater than FAs (97.4% vs. 81.1%) during calibration, but slightly worse in validation (73.5% vs 77.3%) and their combination improved the results. All milk samples were processed into ripened model-cheeses, and analyzed by near-infrared-spectrometry (NIRS), by proton-transfer-reaction time-of-flight mass-spectrometry for their volatile organic compound (VOCs) fingerprint and by panel sensory profiling (SENS). Farming-system authentication on cheese samples was less efficient than on milk, but still possible. The instrumental methods yielded similar validation results, better than SENS, and their combination improved the correct classification rate. The efficiency of the different technics was affected by specific farming systems. In conclusion, dairy products could be discriminated for farming-systems with acceptable accuracy, but the methods tested differ in sampling procedure, rapidity and costs.


Assuntos
Queijo/análise , Ácidos Graxos/química , Aromatizantes/análise , Leite/química , Animais , Bovinos , Cromatografia Gasosa , Análise Discriminante , Ácidos Graxos/análise , Feminino , Análise de Alimentos , Espectrometria de Massas , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos Orgânicos Voláteis/análise
19.
J Environ Sci (China) ; 87: 39-48, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791512

RESUMO

Carbon-silica materials with hierarchical pores consisting of micropores and mesopores were prepared by introducing nanocarbon microspheres derived from biomass sugar into silica gel channels in a hydrothermal environment. The physicochemical properties of the materials were characterized by nitrogen physical adsorption (BET), scanning electron microscopy (SEM), and thermogravimetric (TG), and the adsorption properties of various organic waste gases were investigated. The results showed that microporous carbon materials were introduced successfully into the silica gel channels, thus showing the high adsorption capacity of activated carbon in high humidity organic waste gas, and the high stability and mechanical strength of the silica gel. The dynamic adsorption behavior confirmed that the carbon-silica material had excellent adsorption capacity for different volatile organic compounds (VOCs). Furthermore, the carbon-silica material exhibited excellent desorption characteristics: adsorbed toluene was completely desorbed at 150°C, thereby showing superior regeneration characteristics. Both features were attributed to the formation of hierarchical pores.


Assuntos
Modelos Químicos , Compostos Orgânicos Voláteis/química , Adsorção , Biomassa , Carvão Vegetal , Umidade , Interações Hidrofóbicas e Hidrofílicas , Microesferas , Porosidade , Dióxido de Silício/química , Tolueno/química
20.
Food Chem ; 302: 125326, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31416003

RESUMO

Ruminant meat is considered an excellent source of proteins, dietary fatty acids and essential minerals. Grilling is a popular cooking method; however, the high temperatures employ could modify the grilled meat quality and safety. In this study, the effects of novel beer-based marinades infused with herbs and spices on the quality, safety, and sensory perception of grilled beef and moose meat is examined. Unmarinated meat showed high content of volatile lipid oxidation and Maillard reaction products compared to the marinated samples, which contained higher number and abundance of terpenes and sulfur based compounds. Strong relationships between Maillard products and heterocyclic amines formation, as well as between volatile terpenes and the lipophilic antioxidant activity, were observed in the grilled meats. The findings suggest the unfiltered beer-based marinades were effective in reducing lipid oxidation and Maillard reaction compounds formation, while improving the nutritional quality, safety and sensory preference of grilled ruminant meats.


Assuntos
Cerveja , Culinária/métodos , Carne , Ruminantes , Adolescente , Adulto , Aminas/análise , Aminas/química , Animais , Bovinos , Qualidade dos Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Compostos Heterocíclicos/análise , Temperatura Alta , Humanos , Reação de Maillard , Carne/análise , Pessoa de Meia-Idade , Valor Nutritivo , Carne Vermelha , Especiarias , Paladar , Compostos Orgânicos Voláteis/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA