Página 1 dos resultados de 323 itens digitais encontrados em 0.003 segundos

Medicinal and aromatic plants of Cape Verde: characterization of volatile metabolites of endemic and native species

Lima, Illyane Sofia Martins
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
46.59%
As plantas têm sido usadas como remédios pelo homem desde há milhares de anos e várias culturas incluem um amplo conhecimento sobre suas virtudes medicinais. Práticas tradicionais, apoiadas por conhecimentos empíricos, crenças e procedimentos, desempenham um papel importante, primeiramente nos cuidados de saúde das populações e, secundariamente, como evidências etnofarmacológicas disponíveis para o desenvolvimento de fármacos. As plantas aromáticas são associadas a muitas aplicações biológicas e médicas. Elas biossintetizam uma grande variedade de metabolitos secundários voláteis que desempenham importantes papéis eco-fisiológicos, tais como, proteção contra organismos prejudiciais, predadores, patogénicos microbianos, stresse abiótico, calor, desidratação, etc ..., desempenhando também um papel importante na interação com outras plantas e organismos. Os metabolitos voláteis, distintivos das plantas aromáticas, são agentes naturalmente seleccionados para interagir com alvos biológicos. Este trabalho está focado em plantas medicinais e aromáticas de Cabo Verde. Teve por base informação etnofarmacológica recolhida por inquéritos diretos à população, e que conduziu ao estudo dos metabolitos voláteis das espécies aromáticas endémicas e nativas utilizadas na medicina tradicional de Cabo Verde. Reportamos a composição dos isolados voláteis das quatro plantas medicinais aromáticas...

Avaliação da micobiota de grãos de café e dos metabolitos fungicos na qualidade da bebida; Evaluation of coffe bean mycobiota and fungal metabolites on beverage quality

Beatriz Thie Iamanaka
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 27/01/2010 PT
Relevância na Pesquisa
56.63%
O café passa por vários processos até chegar a ser consumido como bebida e vários fatores contribuem para a sua qualidade final, dentre eles a população microbiana presente. A contaminação dos grãos pelos microrgranismos é diversificada, envolvendo a participação de bactérias, bolores e leveduras, com a predominância de um ou outro grupo, dependendo da etapa de processamento dos grãos. Existem evidências, ainda não conclusivas de que vários fungos presentes no café podem produzir uma série de compostos que podem vir a prejudicar a qualidade da bebida. Esta pesquisa teve como objetivos analisar a micobiota dos grãos obtidos em diferentes etapas da cadeia produtiva do café; investigar a produção dos compostos voláteis produzidos pelos isolados e o impacto dos mesmos na qualidade da bebida e; avaliar sensorialmente a bebida, correlacionando com os fungos presentes. A micobiota de 41 amostras de grãos de café cru, de duas regiões produtoras do Brasil, Cerrado Mineiro/MG e Piraju/SP foram analisadas. As amostras foram coletados do pé (cereja), do solo (varreção), do terreiro (maduro, seco e passas no pé e verde) e da tulha (estocagem) e comparados dois tipos de preparo dos grãos: secagem natural e cereja descascado. As amostras de Minas Gerais apresentaram baixa infecção fúngica...

Aplicações de cromatografia gasosa bidimensional abrangente (GCxGC) no estudo de metabólitos voláteis de fungos sapróbios; Applications comprehensive two-dimensional gas chromatography (GC × GC) in the study of volatile metabolites of fungi saprobes

Paula Feliciano de Lima
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/09/2014 PT
Relevância na Pesquisa
46.51%
O uso de compostos voláteis produzidos por fungos como parte das estratégias de biocontrole na prevenção de doenças ocasionadas por fitopatógenos vem impulsionando o mercado de biofungicidas. Neste cenário, a análise do metaboloma utilizando apenas uma técnica analítica é por vezes inviável devido à magnitude química dos compostos bem como de sua faixa de concentração. Desta forma, o trabalho utilizou a combinação de HS-SPME (Microextração em Fase Sólida) aliada à técnica GC×GC-qMS (Cromatografia Gasosa Bidimensional Abrangente acoplada à Espectrometria de Massas Quadrupolar) para a obtenção do perfil metabólico volátil inédito de duas espécies de fungos com potencial ação para biocontrole e indução de resistência a fitopatógenos na agricultura, Curvularia sp e Memnoniella sp. Através de modelagem MPCA e HCA foi possível a obtenção de um perfil cinético característico da produção de compostos voláteis das espécies que delimitou o processo de identificação tentativa destes metabólitos. Hidrocarbonetos e álcoois foram responsáveis pela maior produção volátil de ambas as espécies avaliadas, com destaque para a produção de lactonas como y-octalactona, y-hexalactona e y-hexalactona por Curvularia sp e sesquiterpenos como acoradieno...

Red deer gender and populations analysis using scats’ volatile profile; Perfil volátil de excrementos de veado

Oliveira, Maria João Saraiva de
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
46.2%
Current populations of red deer (Cervus elaphus) in Portugal derive from recent reintroduction processes and natural dispersion movements from Spain. These movements promote the expansion of the species and reproduction among different populations, increasing the need for more sophisticated methodologies able to differentiate populations and determine sex-ratio, two demographic parameters used in the management of populations. Headspace solid phase microextraction and comprehensive two-dimensional chromatography coupled to mass spectrometry for time of flight gas phase mode (HS-SPME/GC×GC– ToFMS) arises as a possible solution to the determination of these parameters. Thus, this work aims to test for differences between red deer populations, using scats from natural fenced red deer populations as a model to distinguish between sexes. The obtained volatiles are an attempt to determine specific sets of compounds or chemical families’ markers for males, females and for each population, targeting the use in wildlife approaches. In fact, results showed that populations and gender successful differentiation was based on a sub-set of probably, diet and chemical communication compounds, respectively. The mechanism underling this differentiation is probably the interaction of genetics and environment leading to changes in animals’ physiology...

Volatile metabolites and other indicators of Penicillium aurantiogriseum growth on different substrates.

Börjesson, T; Stöllman, U; Schnürer, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1990 EN
Relevância na Pesquisa
46.68%
Penicillium aurantiogriseum Dierckx was cultivated on six agar substrates (barley meal agar, oat meal agar, wheat meal agar, malt extract agar, Czapek agar, and Norkrans agar) and on oat grain for 5 days in cultivation vessels provided with an inlet and an outlet for air. Volatile metabolites produced by the cultures were collected on a porous polymer adsorbent by passing an airstream through the vessel. Volatile metabolites were collected between days 2 and 5 after inoculation. CO2 production was simultaneously measured, and after the cultivation period ergosterol contents and the numbers of CFU of the cultures were determined. Alcohols of low molecular weight and sesquiterpenes were the dominant compounds found. During growth on oat grain the production of 8-carbon alcohols and 3-methyl-1-butanol was higher and the production of terpenes was lower than during growth on agar substrates. The compositions of the volatile metabolites from oat grain were more similar to those from wheat grain, which was used as a substrate in a previous investigation, than to those produced on any of the agar substrates. Regarding the agar substrates, the production of terpenes was most pronounced on the artificial substrates (Czapek agar and Norkrans agar) whereas alcohol production was highest on substrates based on cereals. The production of volatile metabolites was highly correlated with the production of CO2 and moderately correlated with ergosterol contents...

Volatile metabolites produced by six fungal species compared with other indicators of fungal growth on cereal grains.

Börjesson, T; Stöllman, U; Schnürer, J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1992 EN
Relevância na Pesquisa
46.63%
Six fungal species, Penicillium brevicompactum, P. glabrum, P. roqueforti, Aspergillus flavus, A. versicolor, and A. candidus, were inoculated on moistened and autoclaved wheat and oat grains. They were cultivated in glass vessels provided with an inlet and outlet for air. Air was passed through the vessels to collect volatile fungal metabolites on porous polymer adsorbents attached to the outlet. Samples were collected at two fungal growth stages. Adsorbed compounds were thermally desorbed, separated by gas chromatography, and identified by mass spectrometry. Differences in the production of volatile metabolites depended more on the fungal species than on the grain type. The fungal growth stage was not an important factor determining the composition of volatiles produced. 3-Methylfuran was produced in similar amounts regardless of the fungal species and substrate (oat versus wheat). The production of volatile metabolites was compared with the production of ergosterol and CO2 and the number of CFU. The production of volatile metabolites was more strongly correlated with accumulated CO2 production than with actual CO2 production and more strongly correlated with ergosterol contents of the grain than with numbers of CFU.

Freon 11 Extraction of Volatile Metabolites Formed by Certain Lactic Acid Bacteria

Tracey, Ralph P.; Britz, Trevor J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1989 EN
Relevância na Pesquisa
46.44%
The volatile metabolites formed by 18 lactic acid bacteria, representing three genera, were extracted from a complex medium by using a Freon 11 extraction method. The Freon extracts were then analyzed by capillary gas chromatography, and certain extracts were analyzed by gas chromatography-mass spectrometry. A total of 35 major peaks, of which 20 were positively identified, were used to differentiate between the various strains. On the basis of the results obtained, it was possible to differentiate between the members of the genera Lactobacillus, Pediococcus, and Leuconostoc, as well as between various species within the genus Leuconostoc. Of the 10 Leuconostoc oenos strains included in this study, 9 yielded similar results, but it was still possible to differentiate between the various strains. L. oenos B66 differed from the other L. oenos strains. Use of the Freon 11 extraction technique to determine volatile metabolites formed by lactic acid bacteria was shown to be highly reproducible and of great value. Furthermore, certain compounds not previously known to be formed by lactic acid bacteria were found.

Volatile Metabolites Controlling Germination in Buried Weed Seeds

Holm, Robert E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1972 EN
Relevância na Pesquisa
46.36%
Velvetleaf (Abutilon theophrasti Medic), morning glory (Ipomoea purpurea [L.] Roth), and wild mustard (Brassica kaber [D.C.] L. C. Wheeler) seeds exhibited decreased germination with increased planting depth in soil. Flushing the soil for 2 minutes each day with air overcame the inhibition. A sealed in vitro system was used to sample the volatile components produced by weed seeds. Inhibition of seed germination was accompanied by decreased O2 levels and production of volatile metabolites identified as acetaldehyde, ethanol, and acetone. The effectiveness of these compounds in reducing germination was dependent on O2 levels.

Identification of Volatile Metabolites from Five Fungal Species Cultivated on Two Media

Sunesson, A.; Vaes, W.; Nilsson, C.; Blomquist, G.; Andersson, B.; Carlson, R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1995 EN
Relevância na Pesquisa
46.26%
Five fungal species, Aspergillus versicolor, Penicillium commune, Cladosporium cladosporioides, Paecilomyces variotii, and Phialophora fastigiata, were cultivated on two media, malt extract agar and dichloran glycerol agar. Culture flasks provided with inlet and outlet tubes were used and purified, and humidified air was constantly led through the flasks. Air samples from the cultures were sorbed on Tenax GR and analyzed by thermal desorption-gas chromatography. The produced volatile metabolites were analyzed by mass spectrometry. Various hydrocarbons, alcohols, ketones, ethers, esters, sulfur-containing compounds, and terpenes were identified. The most commonly produced substances were 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methylfuran, and dimethyl disulfide. The production was highly dependent on both medium and species.

Volatile Metabolites of Pathogens: A Systematic Review

Bos, Lieuwe D. J.; Sterk, Peter J.; Schultz, Marcus J.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.46%
Ideally, invading bacteria are detected as early as possible in critically ill patients: the strain of morbific pathogens is identified rapidly, and antimicrobial sensitivity is known well before the start of new antimicrobial therapy. Bacteria have a distinct metabolism, part of which results in the production of bacteria-specific volatile organic compounds (VOCs), which might be used for diagnostic purposes. Volatile metabolites can be investigated directly in exhaled air, allowing for noninvasive monitoring. The aim of this review is to provide an overview of VOCs produced by the six most abundant and pathogenic bacteria in sepsis, including Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Such VOCs could be used as biological markers in the diagnostic approach of critically ill patients. A systematic review of existing literature revealed 31 articles. All six bacteria of interest produce isopentanol, formaldehyde, methyl mercaptan, and trimethylamine. Since humans do not produce these VOCs, they could serve as biological markers for presence of these pathogens. The following volatile biomarkers were found for identification of specific strains: isovaleric acid and 2-methyl-butanal for Staphylococcus aureus; 1-undecene...

Volatile Metabolites

Rowan, Daryl D.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 25/11/2011 EN
Relevância na Pesquisa
36.57%
Volatile organic compounds (volatiles) comprise a chemically diverse class of low molecular weight organic compounds having an appreciable vapor pressure under ambient conditions. Volatiles produced by plants attract pollinators and seed dispersers, and provide defense against pests and pathogens. For insects, volatiles may act as pheromones directing social behavior or as cues for finding hosts or prey. For humans, volatiles are important as flavorants and as possible disease biomarkers. The marine environment is also a major source of halogenated and sulfur-containing volatiles which participate in the global cycling of these elements. While volatile analysis commonly measures a rather restricted set of analytes, the diverse and extreme physical properties of volatiles provide unique analytical challenges. Volatiles constitute only a small proportion of the total number of metabolites produced by living organisms, however, because of their roles as signaling molecules (semiochemicals) both within and between organisms, accurately measuring and determining the roles of these compounds is crucial to an integrated understanding of living systems. This review summarizes recent developments in volatile research from a metabolomics perspective with a focus on the role of recent technical innovation in developing new areas of volatile research and expanding the range of ecological interactions which may be mediated by volatile organic metabolites.

Multi-Capillary Column-Ion Mobility Spectrometry of Volatile Metabolites Emitted by Saccharomyces Cerevisiae

Halbfeld, Christoph; Ebert, Birgitta E.; Blank, Lars M.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 05/09/2014 EN
Relevância na Pesquisa
46.5%
Volatile organic compounds (VOCs) produced during microbial fermentations determine the flavor of fermented food and are of interest for the production of fragrances or food additives. However, the microbial synthesis of these compounds from simple carbon sources has not been well investigated so far. Here, we analyzed the headspace over glucose minimal salt medium cultures of Saccharomyces cerevisiae using multi-capillary column-ion mobility spectrometry (MCC-IMS). The high sensitivity and fast data acquisition of the MCC-IMS enabled online analysis of the fermentation off-gas and 19 specific signals were determined. To four of these volatile compounds, we could assign the metabolites ethanol, 2-pentanone, isobutyric acid, and 2,3-hexanedione by MCC-IMS measurements of pure standards and cross validation with thermal desorption–gas chromatography-mass spectrometry measurements. Despite the huge biochemical knowledge of the biochemistry of the model organism S. cerevisiae, only the biosynthetic pathways for ethanol and isobutyric acid are fully understood, demonstrating the considerable lack of research of volatile metabolites. As monitoring of VOCs produced during microbial fermentations can give valuable insight into the metabolic state of the organism...

Volatile Metabolite Profiling of Durum Wheat Kernels Contaminated by Fusarium poae

Laddomada, Barbara; Del Coco, Laura; Durante, Miriana; Presicce, Dominique S.; Siciliano, Pietro A.; Fanizzi, Francesco P.; Logrieco, Antonio F.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 17/10/2014 EN
Relevância na Pesquisa
36.56%
Volatile metabolites from mold contamination have been proposed for the early identification of toxigenic fungi to prevent toxicological risks, but there are no such data available for Fusarium poae. F. poae is one of the species complexes involved in Fusarium head blight, a cereal disease that results in significant yield losses and quality reductions. The identification of volatile organic compounds associated with F. poae metabolism could provide good markers to indicate early fungal contamination. To this aim, we evaluated the volatile profile of healthy and F. poae-infected durum wheat kernels by SPME-GC/MS analysis. The production of volatile metabolites was monitored for seven days, and the time course analysis of key volatiles was determined. A total of 29 volatile markers were selected among the detected compounds, and multivariate analysis was applied to establish the relationship between potential volatile markers and fungal contamination. A range of volatile compounds, including alcohols, ketones, esters, furans and aromatics, were identified, both in contaminated and in healthy kernels. However, the overall volatile profile of infected samples and controls differed, indicating that the whole volatile profile, rather than individual volatile compounds...

The significance of volatile antifungal metabolites produced by trichomerma harzianum biotype Th4, in green-mould disease of commercial mushroom crops /

Krupke, Oliver A.
Fonte: Brock University Publicador: Brock University
Tipo: Electronic Thesis or Dissertation
ENG
Relevância na Pesquisa
36.55%
The aggressive mushroom competitor, Trichoderma harzianum biotype Th4, produces volatile antifungal secondary metabolites both in culture and during the disease cycle in compost. Th4 cultures produced one such compound only when cultured in the presence of Agaricus bisporus mycelium or liquid medium made from compost colonised with A. bisporus. This compound has TLC and UVabsorption and characteristics indicating that it belongs to a class of pyrone antibiotics characterised from other T. harzianum biotypes. UV absorption spectra indicated this compound was not 6-pentyl-2H-pyran-one (6PAP), the volatile antifungal metabolite widely described in Th1. Furthermore, this compound was not produced by Th1 under any culture conditions. Mycelial growth of A. bisporus, Botrytis cinerea and Sclerotium cepivorum was inhibited in the presence of this compound through volatility , diffusion and direct application. This indicates that Th4 produces novel, volatile, antifungal metabolites in the presence of A. bisporus that are likely involved in green mould disease of mushroom crops.

Volatile exometabolone analysis of Aspergillus niger and search for molecular biomarkers pattern; Análise do exometaboloma volátil de Aspergillus niger e pesquisa de um padrão de biomarcadores moleculares

Costa, Carina Filipa Pedrosa da
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
46.7%
Fungal infections have greatly increased in risk populations, namely in immunocompromised patients, probabily because the diagnosis of fungal infections is delayed. Microbial metabolomics arises as a powerful feature screening the metabolites produced by microorganisms. It provides information regarding the state of biological organisms which can be used as a diagnostic tool for diseases through fungal metabolites pattern. Thus, this research aimed to in-depth study of the Aspergillus niger exometabolome, in order to establish a targeted metabolomic pattern that characterizes A. niger. A methodology based on headspace-solid phase microextraction combined with comprehensive two-dimensional gas chromatography coupled to mass spectrometry with a high resolution time of flight analyser (HS-SPME/GC×GC-ToFMS) was used. A. niger exometabolome was analysed in different growth conditions: temperature (25 and 37 °C), incubation time (3 and 5 days), and culture medium (solid and liquid medium). A. niger exometabolome included 430 metabolites, distributed over several chemical families, being the major ones alcohols, aldehydes, esters, hydrocarbons, ketones and terpenoids. Differences among volatile metabolites produced under different growth conditions were observed...

A rapid method for profiling of volatile and semi-volatile phytohormones using methyl chloroformate derivatisation and GC–MS

Rawlinson, Catherine; Kamphuis, Lars G.; Gummer, Joel P. A.; Singh, Karam B.; Trengove, Robert D.
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.53%
Phytohormones are central components of complex signalling networks in plants. The interplay between these metabolites, which include abscisic acid (ABA), auxin (IAA), ethylene, jasmonic acid (JA) and salicylic acid (SA), regulate plant growth and development and modulate responses to biotic and abiotic stress. Few methods of phytohormone profiling can adequately quantify a large range of plant hormones simultaneously and without the requirement for laborious or highly specialised extraction protocols. Here we describe the development and validation of a phytohormone profiling protocol, based on methyl-chloroformate derivatisation of the plant metabolites and analysis by gas chromatography/mass spectrometry (GC–MS). We describe the analysis of 11 metabolites, either plant phytohormones or intermediates of phytohormone metabolism; ABA, azelaic acid, IAA, JA and SA, and the phytohormone precursors 1-aminocyclopropane 1-carboxylic acid, benzoic acid, cinnamic acid, 13-epi-12-oxophytodienoic acid (13-epi-OPDA), linoleic acid and linolenic acid, and validate the isolation from foliar tissue of the model legume Medicago truncatula. The preparation is insensitive to the presence of water, facilitating measurement of the volatile metabolites. Quantitation was linear over four orders of magnitude...

Profiling allergic asthma volatile metabolic patterns using a headspace-solid phase microextraction/gas chromatography based methodology

Caldeira, M.; Barros, A. S.; Bilelo, M. J.; Parada, A.; Câmara, J. S.; Rocha, S. M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /06/2011 ENG
Relevância na Pesquisa
46.2%
Allergicasthmarepresentsanimportantpublichealthissuewithsignificantgrowthovertheyears,especially in the paediatric population. Exhaled breath is a non-invasive, easily performed and rapid method forobtainingsamplesfromthelowerrespiratorytract.Inthepresentmanuscript,themetabolicvolatile profiles of allergic asthma and control children were evaluated by headspace solid-phase microextraction combined with gas chromatography–quadrupole mass spectrometry (HS-SPME/GC–qMS). The lack ofstudiesinbreathofallergicasthmaticchildrenbyHS-SPMEledtothedevelopmentofanexperimental design to optimize SPME parameters. To fulfil this objective, three important HS-SPME experimental parameters that influence the extraction efficiency, namely fibre coating, temperature and time extractions were considered. The selected conditions that promoted higher extraction efficiency corresponding to the higher GC peak areas and number of compounds were: DVB/CAR/PDMS coating fibre, 22◦C and 60min as the extraction temperature and time, respectively. The suitability of two containers, 1L Tedlar® bags and BIOVOC®, for breath collection and intra-individual variability were also investigated. The developed methodology was then applied to the analysis of children exhaled breath with allergicasthma(35)...

Investigation of urinary volatile organic metabolites as potential cancer biomarkers by solid-phase microextraction in combination with gas chromatography-mass spectrometry

Silva, C. L.; Câmara, J. S.
Fonte: Cancer Research UK Publicador: Cancer Research UK
Tipo: Artigo de Revista Científica
Publicado em /11/2011 ENG
Relevância na Pesquisa
46.74%
BACKGROUND: Non-invasive diagnostic strategies aimed at identifying biomarkers of cancer are of great interest for early cancer detection. Urine is potentially a rich source of volatile organic metabolites (VOMs) that can be used as potential cancer biomarkers. Our aim was to develop a generally reliable, rapid, sensitive, and robust analytical method for screening large numbers of urine samples, resulting in a broad spectrum of native VOMs, as a tool to evaluate the potential of these metabolites in the early diagnosis of cancer. METHODS: To investigate urinary volatile metabolites as potential cancer biomarkers, urine samples from 33 cancer patients (oncological group: 14 leukaemia, 12 colorectal and 7 lymphoma) and 21 healthy (control group, cancer-free) individuals were qualitatively and quantitatively analysed. Dynamic solid-phase microextraction in headspace mode (dHS-SPME) using a carboxenpolydimethylsiloxane (CAR/PDMS) sorbent in combination with GC-qMS-based metabolomics was applied to isolate and identify the volatile metabolites. This method provides a potential non-invasive method for early cancer diagnosis as a first approach. To fulfil this objective, three important dHS-SPME experimental parameters that influence extraction efficiency (fibre coating...

Effectiveness of different solid-phase microextraction fibres for differentiation of selected Madeira island fruits based on their volatile metabolite profile: identification of novel compounds

Pereira, João; Pereira, Jorge; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /01/2011 ENG
Relevância na Pesquisa
46.54%
A headspace solid-phase microextraction (HS-SPME) procedure based on five commercialised fibres (85 μm polyacrylate – PA, 100 μm polydimethylsiloxane – PDMS, 65 μm polydimethylsiloxane/divinylbenzene – PDMS/DVB, 70 μm carbowax/divinylbenzene – CW/DVB and 85 μm carboxen/polydimethylsiloxane – CAR/PDMS) is presented for the characterization of the volatile metabolite profile of four selected Madeira island fruit species, lemon (Citrus limon), kiwi (Actinidia deliciosa), papaya (Carica papaya L.) and Chickasaw plum (Prunus angustifolia). The isolation of metabolites was followed by thermal desorption gas chromatography–quadrupole mass spectrometry (GC–qMS) methodology. The performance of the target fibres was evaluated and compared. The SPME fibre coated with CW/DVB afforded the highest extraction efficiency in kiwi and papaya pulps, while in lemon and plum the same was achieved with PMDS/DVB fibre. This procedure allowed for the identification of 80 compounds, 41 in kiwi, 24 in plums, 23 in papaya and 20 in lemon. Considering the best extraction conditions, the most abundant volatiles identified in kiwi were the intense aldehydes and ethyl esters such as (E)-2-hexenal and ethyl butyrate, while in Chicasaw plum predominate 2-hexenal...

Dynamic headspace solid-phase microextraction combined with one-dimensional gas chromatography–mass spectrometry as a powerful tool to differentiate banana cultivars based on their volatile metabolite profile

Pontes, Marisela; Pereira, Jorge; Câmara, José S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /04/2012 ENG
Relevância na Pesquisa
46.67%
In this study the effect of the cultivar on the volatile profile of five different banana varieties was evaluated and determined by dynamic headspace solid-phase microextraction (dHS-SPME) combined with one-dimensional gas chromatography–mass spectrometry (1D-GC–qMS). This approach allowed the definition of a volatile metabolite profile to each banana variety and can be used as pertinent criteria of differentiation. The investigated banana varieties (Dwarf Cavendish, Prata, Maçã, Ouro and Platano) have certified botanical origin and belong to the Musaceae family, the most common genomic group cultivated in Madeira Island (Portugal). The influence of dHS-SPME experimental factors, namely, fibre coating, extraction time and extraction temperature, on the equilibrium headspace analysis was investigated and optimised using univariate optimisation design. A total of 68 volatile organic metabolites (VOMs) were tentatively identified and used to profile the volatile composition in different banana cultivars, thus emphasising the sensitivity and applicability of SPME for establishment of the volatile metabolomic pattern of plant secondary metabolites. Ethyl esters were found to comprise the largest chemical class accounting 80.9%, 86.5%...