Search results for "Gas-Chromatography"
showing 6 items of 16 documents
Metabolomic analysis of plasma from Alzheimer disease patients
2011
Alzheimer Disease is a degenerative disease characterized by progressive impairment of cognitive function. The main feature of AD the generation of an abnormal peptide, beta amyloid 42 (Ab42) from Amyloid Precursor Protein (APP). Ab42 is the main constituent of neurotangles and amyloid plaques, microscopic lesions found in AD patients brain. Ab42 triggers an inflammatory response that is responsible for most of the observed tissue damage. The diagnosis of AD is a complex task, mostly based on imaging techniques and clinical evaluation of the patient’s neurological and cognitive functions. The search for plasma biomarkers able to detect early mild cognitive impairment is one of the recent at…
Volatile profiles of Sicilian prickly pear (Opuntia ficus indica) by SPME-GC/MS analysis
2005
The aroma compounds present in the headspace of homogenized slurries of fresh prickly pears (Opuntia ficus-indica) from Sicilian cultivars were determined. Solid Phase Microextraction (SPME) followed by Gas-chromatography/Mass Spectrometry (GC/MS) analysis was used to characterize the volatile compounds. The volatile flavour profiles of the three cultivars investigated (red, white and yellow) showed significant differences. The aromatic profile of peeled prickly pears stored for one day was different from the one of the fresh samples, mainly due to the occurrence of some oxidative and hydrolytic reactions
Sensory and chemical drivers of wine minerality aroma: An application to Chablis wines
2017
The goal of this work was to evaluate the effect of vineyard position on the minerality of wines and to establish relationships between minerality scores, sensory descriptors and chemical composition. Sensory analyses included minerality rating and free description performed by wine professionals under two conditions: orthonasal olfaction alone and global tasting. Chemical characterization included analysis of major and minor volatile compounds, volatile sulphur compounds, mercaptans, metals, anions and cations. Results showed a significant effect of the river bank on wine minerality scores only in the orthonasal olfaction condition, samples from the left being more mineral than those from …
The caramel flavour: impacts of the volatile and the non-volatile fraction on perception
2013
The aim of this thesis was to investigate the impact of the volatile odorant fraction and the non-volatile fraction on the perception of caramel flavour. The first step focused on the analytical characterization of the volatile odorant fraction of caramel using Gas Chromatography coupled to Olfactometry (GC/O), GC/Mass Spectrometry (GC/MS) and heart-cutting MDGC/MS/O. Results highlighted the presence of more than one hundred compounds and demonstrated the complexity of the caramel volatile fraction. The objective of the second step was to understand the contribution of odorant compounds identified to the caramel aroma typicality. Literature shows that odour intensity is not sufficient to ev…
Different sample treatment approaches for the analysis of T-2 and HT-2 toxins from oats-based media.
2010
A LC-DAD method is proposed for the determination of the T-2 and HT-2 toxins in cultures of Fusarium langsethiae in oat-based and other in vitro media. Test media consisted of freshly prepared milled oats to which T-2 and HT-2 toxin stock solutions were added. Different mixtures of extraction solvent (acetonitrile:water and methanol water), extraction times (30', 60' or 90') and drying methods were investigated. Results showed that extraction with methanol: water (80:20, v/v) for 90 min, drying with N-2 and subsequent analysis by LC-DAD was the fastest and most user friendly method for detecting HT-2 and T-2 toxins production by F. langsethiae strains grown on oat-based media at levels of 0…
Variations in the Chemical Composition of the Essential Oil of Lavandula angustifolia Mill., Moldoveanca 4 Romanian Variety
2020
International audience; In this research, the variations in the chemical composition of the Lavandula angustifolia Mill. essential oil, the Romanian variety Moldoveanca 4, obtained from the same culture, in the same harvesting and extraction conditions, during the years 2016-2018, representing the years 2-4 of culture. Lavandula angustifolia Mill. flowers were supplied from an ecological-crops from N-E Romania and the essential oils were obtained by hydro distillation of freshly harvested flowers. To determine the chemical composition, the essential oil was semi-quantitatively analysed by using gas chromatography coupled with mass spectrometry (GC-MS). In all the samples, 30 organic compoun…