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Biomedical subjects

Xavier Fernandez

Publications and source records attributed to Xavier Fernandez.

7 recordsLinked to original sources
PubMed2006

Comparison of the amounts of volatile compounds in French protected designation of origin virgin olive oils.

Headspace solid-phase microextraction (HS-SPME) -gas chromatography using flame ionization detection and multivariate analysis were applied to the study of the specificity of protected designation of origin (PDO) virgin olive oils produced in a southern French region (Alpes-Maritimes) based on their volatile compounds. A total of 35 PDO olive oils from Nice, 6 commercial oils, and 12 other French PDO olive oils were analyzed. Recorded data were subjected to principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). The method developed here was able to perfectly distinguish different qualities of olive oils. Representative samples from each class obtained by chemometric treatment were analyzed by HS-SPME and GC-MS. PCA and SIMCA of chromatographic data were related to sensory analysis and led to a better understanding of the chemical features and observed sensory effects of olive oils.

Chromatography, Gas↗
PubMed2006

Characterization of the chemical composition of a byproduct from siam benzoin gum.

The mixture of bark and gum obtained after size-grading of Siam benzoin gum was studied to establish its potential application as a valuable new grade of the balsamic resin. An analysis of its volatile constituents by means of static headspace and SPME led to the identification of 26 and 50 compounds, respectively. Significant differences were observed in both the headspace composition and olfactory properties of the byproduct as compared to those of Siam benzoin gum. This prompted the further analysis of its volatile extract and its resinoid by GC techniques, resulting in the identification of 60 (99.5%) and 16 (89.1%) components, respectively. To examine the influence of bark pieces, different extracts obtained from the raw material and from a sorted sample were analyzed by GC and HPLC techniques. The chemical compositions and the yields determined for the two resinoids lead to the conclusion that this harvesting byproduct is a new grade of Siam benzoin gum, providing interesting olfactory notes that differ from those of other grades.

Gas Chromatography-Mass Spectrometry↗
PubMed2006

Enantiomer separation of 1,4-sulfanylalcohols by conventional and low-temperature gas chromatography.

Since 1990, the family of organosulfur molecules has assumed increasing importance in pheromone, flavour, and fragrance chemistry. Depending on the constitution of the functional groups, various volatile sulfur-containing compounds are chiral. However, hitherto it has been impossible to study the chirality of 1,4-sulfanylalcohols, since no adequate enantioselective analytical technique has been available. Here we report on the enantiomer separation of ten volatile 1,4-sulfanylalcohol homologues by applying an heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin phase, involving in some cases the use of a low-temperature gas chromatographic (ltGC) technique. The results are expected to open research potential on the asymmetry of volatile organosulfur molecules, particularly in the fields of pheromone, flavour, and fragrance research.

Alcohols↗
PubMed2005

Composition and antibacterial activity of Pseudocytisus integrifolius (Salisb.) essential oil from Algeria.

The essential oil composition of an endemic Algerian Cruciferae, Pseudocytisus integrifolius (Salisb.) Rehder, was analyzed by gas chromatography (GC) and GC-mass spectrometry (MS). Eighty-three components representing more than 96.5% of the oil were identified. The major components were dimethyl disulfide (33.4%), dimethyl trisulfide (24.2%), and an unsaturated nitrile (31.7%). Fractionation on a silica gel column led to the identification of trace-level compounds, in particular, polar compounds such as nitriles and aldehydes, and to the isolation of dimethyl disulfide, dimethyl trisulfide, and an unsaturated nitrile. Structural analysis using high-resolution mass spectrometry (HRMS) and 1H,13C NMR techniques enabled the identification of pent-4-enenitrile. Variation in essential oil composition and yields was studied according to harvesting time, drying, and parts of the plant. The essential oil of aerial parts was tested for its antibacterial activity using a paper disk method. The oil was effective on the inactivation of Escherichia coli and Pseudomonas aeruginosa and ineffective on the inactivation of Staphylococcus aureus.

Algeria↗
PubMed2003

Comparison of static headspace, headspace solid phase microextraction, headspace sorptive extraction, and direct thermal desorption techniques on chemical composition of French olive oils.

Static headspace (SHS), headspace solid phase microextraction (HS-SPME), headspace sorptive extraction (HSSE), and direct thermal desorption (DTD) were applied to the analysis of four French virgin olive oils from Corsica. More than 60 compounds were isolated and characterized by GC-RI and GC-MS. SHS was not suited to the characterization of olive oil volatile compounds because of low sensitivity. The SPME and HSSE techniques were successfully applied to olive oil headspace analysis. Both methods allow the characterization of volatile compounds (mainly C(6) aldehydes and alcohols), which contribute significantly to the "green" flavor note of virgin olive oils. The PDMS stir bar showed a higher concentration capacity than a DVB/CAR/PDMS SPME fiber due to the higher volume of polymeric coating. DTD was a very good tool for extracting volatile and especially semivolatile compounds, such as sesquiterpenes, but requires a significant investment like that for HSSE. Finally, SPME may be a more appropriate technique for routine quality control due to its operational simplicity, repeatability, and low cost.

Chromatography, Gas↗
PubMedDate not supplied

Genetic parameters of meat technological quality traits in a grand-parental commercial line of turkey.

Genetic parameters for meat quality traits and their relationships with body weight and breast development were estimated for a total of 420 male turkeys using REML. The birds were slaughtered in a commercial plant and the traits measured included pH at 20 min (pH20) and 24 h post-mortem (pHu) and colour of the breast and thigh meat. The heritabilities of the rate and the extent of the pH fall in the breast muscle were estimated at h2=0.21 +/- 0.04 and h2=0.16 +/- 0.04, respectively. Heritabilities ranging from 0.10 to 0.32 were obtained for the colour indicators in the breast muscle. A marked negative genetic correlation (rg=-0.80 +/- 0.10) was found between pH20 and lightness (L*) of breast meat, both traits corresponding to PSE indicators. The pH20 in the thigh muscle had a moderate heritability (h2=0.20 +/- 0.07) and was partially genetically related to pH20 in the breast muscle (rg=0.45 +/- 0.17). Body weight and breast yield were positively correlated with both initial and ultimate pH and negatively with the lightness of breast meat.

Animals↗