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Search Results: 1 - 10 of 3330 matches for " Volatile Compounds "
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Monitoring of Lactic Fermentation with a Coupling Electronic Nose and Gas Chromatography  [PDF]
Montserrat Calderon-Santoyo, Pedro Ulises Bautista-Rosales, Guadalupe Luna-Solano, Charles Ghommidh, Juan Arturo Ragazzo-Sanchez
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.59A002

In this work, the performance of dehydratation-desalcoholization system based on an electronic nose coupled to gas chromatography was tested. The system was used for monitoring the volatile compounds produced during a lactic fermentation with a heterofermentative bacteria (Lactobacillus fermentum Ogi E1). The monitoring was carried out with dehydratation and desalcoholization or dehydratation only, on the basis of low ethanol concentration produced by this bacteria. In the first case, fermentation head-space analyses showed low signals from each gas sensor, then the principal components analyses (PCA) resulted confused. However with the only dehydratation system, the electronic nose was able to detect some volatile compounds during bioprocess. The PCA showed a single distribution, permitting to conclude that principal component 1 represented the ethanol concentration. The system is appropriate to monitor some parameters during the fermentations process as ethanol, lactate and biomass concentration.

Identification and Recovery of Volatiles Organic Compounds (VOCs) in the Coffee-Producing Wastewater  [PDF]
Alcilucia Oliveira, Lourdes M. C. Cabral, Humberto Bizzo, Neusa P. Arruda, Suely P. Freitas
Journal of Water Resource and Protection (JWARP) , 2014, DOI: 10.4236/jwarp.2014.64039

The objectives of the present study were to recover and identify volatiles organic compounds (VOCs) in the wastewater (WW) coming from a soluble coffee industrial plant. For VOCs recover, the WW was concentrated by pervaporation using a polydimethylsiloxane (PDMS) membrane. Furthermore, the solid phase micro extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) were used for VOCs identification. The multivariate method of principal component analysis (PCA) was performed to evaluate differences amongst the feed and concentrate streams. Regarding the number of VOCs identified in the wastewater (33) and permeate (72), a significant statistical difference at p < 0.05 was observed. Clusters discriminating were clearly observed, as the feed and permeate streams are compared. Thus, we can conclude that pervaporation process using a PDMS membrane was effective to recover different class of VOCs present in the aqueous effluent and can be recommended for industrial wastewater treatment.

Substancias voláteis em mel floral e mel de melato
CAMPOS, Gisélia;NAPPI, Giancarlo U.;RASLAN, Délio S.;AUGUSTI, Rodinei;
Ciência e Tecnologia de Alimentos , 2000, DOI: 10.1590/S0101-20612000000100004
Abstract: although honey seems to possess a characteristic flavor, variety of flowers avaiable to bees gives differents flavors and aromas, indicating the presence of various volatile compounds. some of these also depends on the phisiology of the bee, the processing after harvest and in honeydew honey there is the interference of sucking insects and ants. many volatile substances have already been identified and some of them are specific of typical unifloral honeys. with the purpose of finding a characteristic volatile substance of honeydew honey, six samples of this kind and six floral honeys were analysed by extraction using hidrogen steam and gas chromathography with mass spectrometry. acetic acid has been found in four honeydew honey and in one floral honey, but with less abundance.
Constituintes voláteis de própolis piauiense
Torres, Raimundo Nonato Soares;Lopes, José Arimatéia Dantas;Moita Neto, José Machado;Citó, Ant?nia Maria das Gra?as Lopes;
Química Nova , 2008, DOI: 10.1590/S0100-40422008000300003
Abstract: the essential oils of five samples obtained in different regions of the state of piaui were analyzed by gc-ms. ninety-one volatile constituents were tentatively identified and eight were positively identified. the principal components obtained from each sample were: 1,8-cineole, exo-fenchol, terpin-4-ol and fenchone (teresina), a-pinene, caryophyllene oxide, b-pinene and a-copaene (pio ix), (e)-caryophyllene, a-copaene, a-pinene, caryophyllene oxide and d-cadinene (campo maior), (e)-caryophyllene, a-gurjunene and b-selinene (pedro ii) and (e)-caryophyllene, a-gurjunene, d-cadinene and a-copaene (lagoa de sao francisco). the five samples presented differences in the chemical composition of volatile fractions. the studies pointed out the need of characterizing propolis from piaui by geographic regions and by seasons (drought and rainy periods).
Composi??o química volátil, em diferentes estádios de matura??o, de manga 'Tommy Atkins' produzida no Vale do S?o Francisco
Canuto, Kirley Marques;Souza Neto, Manoel Alves de;Garruti, Deborah dos Santos;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000900027
Abstract: the effect of the maturation stages on the volatile chemical composition of mango fruit cv. tommy atkins, cultivated in s?o francisco valley, was investigated using spme. gc/ms and gc-fid analysis allowed the identification of 32 compounds, consisting mainly of monoterpenes. δ-3-carene was the major component in all the stages, while α-terpinolene, trans-β-caryophyllene e α-pinene succeded each other as the second most abundant constituent, during the ripening. the aroma of the ripe fruit was characterized by presence of short-chain ethyl esters (c2-c6), whereas the green mango contained the highest concentration of δ-3-carene. furthermore, some terpenes were detected exclusively at one of the stages.
Scientific Annals of Alexandru Ioan Cuza University of Iasi. New Series, Section 2. Vegetal Biology , 2009,
Abstract: The paper presents the anatomical structure’s peculiarities and the composition in volatile oils of the mature fruit in Peucedanum austriacum and Heracleum sphondylium species.
Apparent Solubility of Natural Products Extracted with Near-Critical Carbon Dioxide  [PDF]
Helena Sovová
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.312A127

The apparent solubility controls the initial stage of supercritical fluid extraction of natural products, which is most important for the process economics. Based on the literature, data on CO2 apparent solubility of volatile substances from different matrices as leaves, flowers, rhizomes and seeds were collected and compared with their thermodynamic solubility. The adsorption isotherm derived by del Valle and Urrego as a modification of the isotherm proposed by Perrut et al. is universal enough to interpret these data as well as the apparent solubility of vegetable oils from seeds, for which it was originally proposed. When the apparent solubility of minor extract components in CO2 is compared with their thermodynamic solubility, their fraction in the extracted mixture should be taken into account.

Diurnal and Seasonal Variation of BTX in Ambient air of One Urban Site in Carmen City, Campeche, Mexico  [PDF]
J. G. Cerón, E. Ramírez, R. M. Cerón, C. Carballo, C. Aguilar, U. López, A. Ramírez, Y. Gracia, D. Naal, A. Campero, J. Guerra, E. Guevara
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.48A1006

BTX (benzene, ethylbenzene, toluene and p-xylene) and meteorological parameters were measured in ambient air of an urban site located in Carmen City, Campeche, Mexico. A total of 412 samples were collected for BTX and analyzed by Gas Chromatography with Flame Ionization Detection (GC-FID). Meteorological parameters were measured by a portable station. A marked diurnal variation was found for all measured BTX. The highest concentrations occurred during midday (13:00-14:30 h). A clear seasonal pattern was observed too for all compounds registering their highest levels during summer sampling period. Mean concentrations for benzene, ethylbenzene, toluene and p-xylene were: 5.42, 3.97, 11.24 and 8.32 ppbv, respectively. BTX abundance showed the following order: toluene > p-xylene > benzene > ethylbenzene. BTX maximum concentrations were found when winds blowed from E and NE. Important oil industry sources and avenues are located at these directions. These sources could contribute to the levels of BTX in this site.

Quantification of Mayor Volatile Compounds from Artisanal Agave Distilled: Bacanora  [PDF]
Maritza Lizeth álvarez-Ainza, Humberto González-Ríos, Alberto González-León, ángel Javier Ojeda-Contreras, Ana Isabel Valenzuela-Quintanar, Evelia Acedo-Félix
American Journal of Analytical Chemistry (AJAC) , 2013, DOI: 10.4236/ajac.2013.411082

Bacanora is an artisanal beverage distilled from agave, which is manufactured on a small scale in the Sonora state, México. The aim of this study was to identify the major volatile compounds in 77 artisanal Bacanora beverages by gas chromatography, to determine the samples that comply with the Mexican Standards for Bacanora. The samples were collected in 28 municipalities in the area of origin denomination. It was found that only 55.8% of the samples (43) meet the parameters established in the Official Mexican Standards, whereas 44.2% of the samples (34) do not comply: 3 samples for alcohol content, 8 for acetaldehyde, 1 for esters, 11 for methanol and 17 for higher alcohols. Some of the samples do not comply because of more than one analyzed parameter. The Bacanora samples showed great variability among the sampled regions as well as within the same municipalities (p ≤ 0.05).

Isolation and Characterization of Volatile Organic Compounds-Degrading Bacillus Strains from Loess  [PDF]
Soo Yeon Lee, Hye Yun Oh, Ok Bin Kim
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.44A007

Volatile organic compounds (VOCs) are harmful to human health and the environment. Recently, loess (Hwangtoh) was used as an eco-friendly interior paint formulation in Korea. It is used even more commonly as a filter carrier to remove VOCs. In this study, we isolated Bacillus strains from a loess filter. The strains that were tolerant to VOCs were labeled according to the series VOC01 to VOC35. Four strains—VOC03, VOC11, VOC18, and VOC30—were investigated for their ability to degrade cyclohexane and toluene. Strain VOC18 best degraded both VOCs, whereas VOC03 demonstrated no ability to degrade VOCs. In keeping with this, VOC18 grew best on cyclohexane or toluene as the sole carbon source. The strains were identified by their physiochemical and phylogenetic characteristics. Strain VOC18 was determined as a strain of Bacillus cereus; VOC11 and VOC30 were determined as differentiated strains of B. thuringiensis. Strain VOC03, which demonstrated high tolerance but no ability to degrade VOCs, was identified as a strain of B. megaterium.

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