Search results for "compounds"

Dry vs soaked wood: Modulating the volatile extractible fraction of oak wood by heat treatments

2012

The aim of this study was to analyze the impact of the water content of wood on the concentrations of volatile compounds which can be extracted after heat treatments. Head Space-Solid Phase Micro Extraction Gas Chromatography coupled to Mass Spectrometry (HS-SPME GC-MS) has been used to compare the concentrations of six aroma compounds (vanillin, furfural, eugenol, guaiacol and cis- and trans-whisky lactones) in hydroalcoholic extracts of heated oak wood samples either previously soaked in hot water or not. Except for eugenol, concentrations of extracted aromas appeared to be lower in soaked woods than in dry woods for temperatures up to 200 °C. If a delaying effect of water could explain s…

Towards Iron(II) Complexes with Octahedral Geometry: Synthesis, Structure and Photophysical Properties

2020

The control of ligand-field splitting in iron (II) complexes is critical to slow down the metal-to-ligand charge transfer (MLCT)-excited states deactivation pathways. The gap between the metal-centered states is maximal when the coordination sphere of the complex approaches an ideal octahedral geometry. Two new iron(II) complexes (C1 and C2), prepared from pyridylNHC and pyridylquinoline type ligands, respectively, have a near-perfect octahedral coordination of the metal. The photophysics of the complexes have been further investigated by means of ultrafast spectroscopy and TD-DFT modeling. For C1, it is shown that&mdash

Dynamics of copper and zinc sedimentation in a lagooning system receiving landfill leachate.

2013

9 pages; International audience; This study characterises the sediment dredged from a lagooning system composed of a settling pond and three lagoons that receive leachates from a municipal solid waste (MSW) landfill in France. Organic carbon, carbonate, iron oxyhydroxides, copper (Cu) and zinc (Zn) concentrations were measured in the sediment collected from upstream to downstream in the lagooning system. In order to complete our investigation of sedimentation mechanisms, leachates were sampled in both dry (spring) and wet (winter) seasonal conditions. Precipitation of calcite and amorphous Fe-oxyhydroxides and sedimentation of organic matter occurred in the settling pond. Since different di…

Global sea-to-air flux climatology for bromoform, dibromomethane and methyl iodide

2013

Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr3), dibromomethane (CH2Br2) and methyl iodide (CH3I). The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface ob…

Effect of cropping cycles and repeated herbicide applications on the degradation of diclofop-methyl, bentazone, diuron, isoproturon and pendimethalin…

2002

A greenhouse study was conducted to investigate the ability of four crops (wheat, corn, oilseed rape and soybean) to influence the degradation of bentazone, diclofop-methyl, diuron, isoproturon and pendimethalin in soil. The present study showed that microbial biomass-carbon was significantly higher in planted soils than in bulk soil, especially with wheat and corn, after several cropping cycles. The biomass in corn and soybean planted soils was adversely affected by bentazone but recovered after three cropping cycles. In wheat-planted soils, diclofop-methyl application resulted in persistent increase of the amount of microbial biomass. Bentazone did not show accelerated degradation even af…

Effect of onion consumption by rats on hepatic drug-metabolizing enzymes

2001

Fruits and vegetables or their natural constituents which increase detoxication enzymes and/or reduce activating enzymes are considered as good candidates to prevent chemically-induced carcinogenesis. In this study, rats were fed a diet supplemented with 20% onion powder for 9 days. Several cytochrome P450 (CYP)s enzymes (CYP 1A, 2B, 2E1, 3A), which are involved in carcinogen activation, were determined by measuring their enzyme activities using specific substrates. In addition, phase II enzymes activities such as UDP-glucuronosyltransferase (UGT) and glutathione S-transferase (GST), involved in detoxication of carcinogens, were measured. Protein levels of CYPs and GST A1/A2, A3/A5, Ml, M2 …

Diversité génétique et aromatique de la truffe de Bourgogne

2013

Truffles are ectomycorrhizal Ascomycota fungi belonging to the Tuberaceae family and more specifically to the Tuber genus. More than thirty Tuber species are currently described in Europe. In this thesis, we specifically focused on the Tuber aestivum-uncinatum model. This truffle is commonly called "Burgundy Truffle" and has a gastronomic and cultural interest.The first part of this thesis focused on the taxonomic status of the Burgundy truffle (Tuber uncinatum). For this, we used a multi-marker approach combining several genetic markers commonly used at the interspecific scale. Our analyses showed that the two taxa, Tuber aestivum (summer truffle) and Tuber uncinatum are conspecific.In the…

Flavour formation in foods

2022

Sensitivity to allyl isothiocyanate, dimethyl trisulfide, sinigrin, and cooked cauliflower consuption

2006

International audience; The consumption of cauliflower consumers has been related to the olfactory and gustatory sensitivities to potentially objectionable flavor compounds in this vegetable. Based on the ascending concentration series method of limits, a first experiment was designed to develop rapid tests dedicated to estimate individuals' olfactory thresholds for allyl isothiocyanate (AITC) and dimethyl trisulfide (DMTS) and gustatory thresholds for sinigrin (SIN). The best compromise between rapidity and reliability was obtained with two replications of a four-alternative forced choice (AFC) at six ascending concentrations (6×2×4-AFC) for both AITC and DMTS, and with a 6×1×4-AFC for SIN…

Evidences of regional differences in chlorine perception by consumers: sensitivity differences or habituation?

2010

Résumé du poster présenté.; Chlorinous flavors are one of the leading cause of customers’ complaints and dissatisfaction with drinking water. To investigate potential regional differences in chlorine perception, sensory testing experiments were conducted in France and in Spain to assess consumers’ sensory sensitivity (chlorine flavor detection threshold) as well as their liking and acceptance for chlorinated solutions. The chlorine flavor detection threshold was found to vary depending on countries (0.17 mg/LCl2 in France and 0.56 mg/LCl2 in Spain). According to the relation found between chlorine practices and average flavor detection thresholds, it is likely that habituation may support o…