Identification of Oxidation Compounds of 1-Stearoyl-2-linoleoyl-sn-glycero-3-phosphoethanolamine during Thermal Oxidation.

Heat-induced oxidative modification of phosphatidylethanolamine molecular species as potential functional food components was investigated. 1-Stearoyl-2-linoleoyl-sn-glycero-3-phosphoethanolamine (SLPE) was chosen as a model. The optimal temperature for hydroperoxide formation was determined by mass spectrometry.

Comparison of the volatiles formed by oxidation of phosphatidylcholine to triglyceride in model systems.

The oxidative stability of oleoyl and linoleoyl residues esterified in the form of triglyceride (TAG) and phosphatidylcholine (PC) during thermal treatment was investigated. Headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis was used to determine the volatile compounds from oxidized PL and TAG molecular species. The results showed that aldehydes were the major volatile oxidized compounds (VOCs) of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC), 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (SLPC), and 1,3-distearoyl-2-linoleoyl-glycerol (SLS), while ketones, especially saturated methyl ketones, were the major VOCs of 1,3-distearoyl-2-oleoyl-glycerol (SOS).

Identification of volatiles from oxidised phosphatidylcholine molecular species using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS).

Headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry analysis (GC-MS) was used to investigate the volatile compounds from oxidised phosphatidylcholine molecular species. 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) and 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (SLPC) were chosen as models. The influence of several parameters on the efficiency of volatile oxidised compounds (VOCs) microextraction, such as type of fibre, extraction duration and temperature were studied.

Effect of heat treatment on the content of individual phospholipids in coffee beans.

In this study, the thermal stability of phospholipids (PLs) extracted from coffee beans was investigated. Chemical analysis was used to obtain information about the effect of heat treatment on the content of PLs in roasted coffee beans. Normal phase high-performance liquid chromatography (HPLC) combined with evaporative light scattering detector (ELSD) was applied to identify and quantify the classes of PLs.

Systemic down-regulation of delta-9 desaturase promotes muscle oxidative metabolism and accelerates muscle function recovery following nerve injury.

The progressive deterioration of the neuromuscular axis is typically observed in degenerative conditions of the lower motor neurons, such as amyotrophic lateral sclerosis (ALS). Neurodegeneration in this disease is associated with systemic metabolic perturbations, including hypermetabolism and dyslipidemia. Our previous gene profiling studies on ALS muscle revealed down-regulation of delta-9 desaturase, or SCD1, which is the rate-limiting enzyme in the synthesis of monounsaturated fatty acids.

SPE for the simultaneous determination of various isothiocyanates.

Several SPE sorbents were investigated for the extraction of a group of chemically diverse isothiocyanates (ITCs). They included bonded silica, carbon-based, and polymer-based sorbents with various functional groups. Results showed large differences in the ability of these sorbents to simultaneously extract ITCs from standard solutions.

Improvement in determination of isothiocyanates using high-temperature reversed-phase HPLC.

The largely adopted reversed-phase HPLC analysis of the molecular species of isothiocyanates (ITCs) was performed and showed losses during the chromatographic run with eight ITCs. These losses, which obviously impact the accuracy of quantitative determinations, were due to precipitation in the chromatographic system. At 22°C, they ranged from 5.

Determination of phosphatidylethanolamine molecular species in various food matrices by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2).

A liquid chromatographic-electrospray ionization-tandem mass spectrometric (LC-ESI-MS(2)) method has been developed for determination of the molecular species of phosphatidylethanolamine (PE) in four food matrices (soy, egg yolk, ox liver, and krill oil). The extraction and purification method consisted of a pressurized liquid extraction procedure for total lipid (TL) extraction, purification of phospholipids (PLs) by adsorption on a silica gel column, and separation of PL classes by semi-preparative normal-phase HPLC. Separation and identification of PE molecular species were performed by reversed-phase HPLC coupled with electrospray ionization tandem mass spectrometry (ESI-MS(2)).

Liquid chromatography-tandem mass spectrometry for the determination of sphingomyelin species from calf brain, ox liver, egg yolk, and krill oil.

In this study, molecular species of sphingomyelin (SM) in egg yolk, calf brain, ox liver, and krill oil were investigated. Classes of phospholipids (PLs) were purified, identified, and quantified by normal phase semipreparative high-performance liquid chromatography (HPLC) combined with evaporative light scattering detectors (ELSD). For SM molecular species identification, pure SM collected through a flow splitter was loaded to HPLC-electrospray ionization-tandem mass spectrometry (LC-ESI-MS(2)), with 100% methanol containing 5 mM ammonium formate as mobile phase.

Simultaneous Determination of Various Isothiocyanates by RP-LC Following Precolumn Derivatization with Mercaptoethanol.

Numerous isothiocyanates (ITCs) are poorly soluble in water which causes their precipitation in aqueous mobile phases used in reversed phase liquid chromatography (RP-LC), thus impacting the accuracy of the quantification. By comparing the amounts of ITCs injected and released from the column, losses could be estimated at 5-32% depending on polarities and concentrations. Results could be dramatically improved in terms of separation and quantification using RP-LC with a mercaptoethanol precolumn derivatization aimed at avoiding ITCs precipitation.

Improvement of total lipid and glycerophospholipid recoveries from various food matrices using pressurized liquid extraction.

The extraction of three major phospholipid (PL) classes contained in soybean, egg yolk, calf brain, and ox liver was investigated by means of two methods. The PL amounts were evaluated. A new method, based on pressurized liquid extraction (PLE), was applied for total lipids (TL), including PL, extraction and compared with a standard liquid extraction method, a modified Folch method.

Oxidative stability at high temperatures of oleyol and linoleoyl residues in the forms of phosphatidylcholines and triacylglycerols.

An investigation was carried out into the stability of fatty acyl groups to heat-induced oxidative changes as affected by their chemical environment. The behavior of oleic and linoleic acyl groups when esterified in triacylglycerols (TAGs) and phosphatidylcholines (PCs) was evaluated. The monitoring of the oxidative degradation using liquid chromatography-mass spectrometry (LC-MS) showed that fatty acyl groups are less likely to be oxidized when in the form of PCs than when in the form of TAGs.

Differentiation of chocolates according to the cocoa's geographical origin using chemometrics.

The determination of the geographical origin of cocoa used to produce chocolate has been assessed through the analysis of the volatile compounds of chocolate samples. The analysis of the volatile content and their statistical processing by multivariate analyses tended to form independent groups for both Africa and Madagascar, even if some of the chocolate samples analyzed appeared in a mixed zone together with those from America. This analysis also allowed a clear separation between Caribbean chocolates and those from other origins.

Investigation of natural phosphatidylcholine sources: separation and identification by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2) of molecular species.

This study is a contribution to the exploration of natural phospholipid (PL) sources rich in long-chain polyunsaturated fatty acids (LC-PUFAs) with nutritional interest. Phosphatidylcholines (PCs) were purified from total lipid extracts of different food matrices, and their molecular species were separated and identified by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS(2)). Fragmentation of lithiated adducts allowed for the identification of fatty acids linked to the glycerol backbone.