Optimization of a solid phase extraction method and hydrophilic interaction liquid chromatography coupled to mass spectrometry for the determination of phospholipids in virgin olive oil

Degradation of the polar lipid and fatty acid molecular species in extra virgin olive oil during storage based on shotgun lipidomics

Among the bioactive compounds present in extra-virgin olive oil, polar lipids and free fatty acids are minor compounds with well-known nutritional values and have been studied for traceability and adulteration investigations as well. In the present paper, the simultaneous characterization of polar lipids and free fatty acids in a pool of fifteen EVOO samples was achieved by means of reversed phase C18 analysis coupled to negative polarity high-resolution mass spectrometry. A total of 24 polar lipids, comprising 19 phospholipids and 5 sulfolipids, and 27 free fatty acids were tentatively identified, including several odd-chain and very long-chain fatty acids at trace levels. Moreover, a one-month study of lipid degradation on simulated storage conditions was carried out thanks to the set-up of a dedicated approach for degradation product analysis which was implemented of Compound Discoverer software. By virtue of the customized data processing workflow, more than forty compounds were tentatively identified, including compounds deriving from hydrolysis and oxidation reactions. Finally, by analysis of peak area trends, phosphoester hydrolyses of polar heads of phospholipids emerged as the fastest reactions, followed by glycerol ester hydrolyses and oxidative processes.

Determination of glycerophospholipids in vegetable edible oils: Proof of concept to discriminate olive oil categories

Glycerophospholipids (GPLs) constitute a chemical family within the saponifiable fraction of vegetable oils. GPLs have been scarcely studied in edible oils owing to the lack of sensitive and selective analytical methods. We have developed a method for identification, confirmation and relative quantitation of GPLs in vegetable oils. The method is based on solid-phase extraction (SPE) for isolation of GPLs and determination by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). As proof of concept, the approach has been applied to characterize GPLs in different olive oil categories, thus revealing compositional changes, which could be explained by factors such as the quality of fruits and the extraction process. Families such as glycerophosphatidic acids and phosphatidylglycerides are remarkable because of their capability to discriminate virgin olive oils from the rest of categories. These results open a door to additional studies targeted at the identification of olive oil quality by monitoring these lipids.

Development and validation of a novel UPLC-ELSD method for the assessment of lipid composition of nanomedicine formulation

Lipid nanocarriers incorporating glycerides, polyethylene glycol (PEG)-stearates and phospholipids have attracted great attention for in vivo diagnostic, in vivo imaging, activated or non-activated targeted drug delivery. For quality control purposes, the development of appropriate methods for the quantification of their lipid components is needed. In the present study, we developed an analytical method for lipid quantification in formulated nanoparticles. PEG-stearates and glycerides were analyzed in a single run by RP-UPLC-ELSD using a two-step gradient elution program, while the analysis of phospholipids was accomplished by HILIC-UPLC-ELSD after isolation using an SPE silica column. Using both isolated compounds and commercial lipid standards, calibration curves were produced using second-order polynomials to attain the quantitative evaluation of each lipid excipient. Relative standard deviation of all analytes was between 0.9% and 5.3% for intra-day precision and recovery ranged from 83.5% to 112.2%. The presented method was successfully implemented to study the manufacturing process and stability of the formulated lipid excipients during long-term storage and accelerated conditions. The formulation lipid yield was determined and found equal to 82.5%.

Polar Lipids from Olives and Olive Oil: A Review on Their Identification, Significance and Potential Biotechnological Applications

Polar lipids are minor components of olives and olive oil and include a myriad of molecules such as phospholipids and glycolipids. Even though sensitive and high-resolution analytical approaches have been used to unveil the polar lipidome of these matrices, new insights on their composition are needed. In this review, we will describe the findings on the identification and characterization of polar lipids from olives and olive oil and the underlying analytical challenges. The significance of polar lipids will also be discussed as potential markers of identity and traceability of olives and olive oil and in detecting adulteration of olive oil. Their potential impact on nutrition and health will be presented as a valuable source of bioactive compounds and as promising ingredients for different uses from olive-derived industrial by-products.

Hydrophilic interaction chromatography in food matrices analysis: An updated review

This review focuses on the most recent papers (from 2011 to submission date in 2017) dealing with the analysis of different organic components in foods (i.e. nucleobases, nucleosides, nucleotides, uric acid, and creatinine, amino acids and related compounds, choline-related compounds and phospholipids, carbohydrates, artificial sweeteners and polyphenolic compounds), using hydrophilic interaction liquid chromatography (HILIC) combined with different detection techniques. For each compound class, the investigated food matrices are grouped per: foods of animal origin, vegetables, fruits and related products, baby food, and other matrices such as drinks and mushrooms/fungi. Furthermore, the main advantages of HILIC chromatography respect to the other commonly used techniques are discussed.

Natural phospholipids: Occurrence, biosynthesis, separation, identification, and beneficial health aspects

During the last years, phospholipids (PLs) have attracted great attention because of their crucial roles in providing nutritional values, technological and medical applications. There are considerable proofs that PLs have unique nutritional benefits on human health, such as reducing cholesterol absorption, improving liver functions, and decreasing the risk of cardiovascular diseases. PLs are the main structural lipid components of cell and organelle membranes in all living organisms, and therefore, they occur in all organisms and the derived food products. PLs are distinguished by the presence of a hydrophilic head and a hydrophobic tail, consequently they possess amphiphilic features. Due to their unique characteristics, the extraction, separation, and identification of PLs are critical issues to be concerned. This review is focused on the content of PLs classes in several sources (including milk, vegetable oils, egg yolk, and mitochondria). As well, it highlights PLs biosynthesis, and the methodologies applied for PLs extraction and separation, such as solvent extraction and solid-phase extraction. In addition, the determination and quantification of PLs classes by using thin layer chromatography, high-performance liquid chromatography coupled with different detectors, and nuclear magnetic resonance spectroscopy techniques.

Simultaneous determination of isoflavones and resveratrols for adulteration detection of soybean and peanut oils by mixed-mode SPE LC-MS/MS

To ensure authenticity of vegetable oils, isoflavones (genistein, genistin, daidzein and daidzin) and resveratrols (cis-resveratrol and trans-resveratrol) were selected as the putative markers for adulteration of soybean and peanut oils. Firstly, mixed mode solid-phase extraction coupled with liquid chromatography tandem mass spectrometry (mixed-mode SPE LC-MS/MS) method was developed to analyze isoflavones and resveratrols in vegetable oils. The concentration of marker compounds in vegetable oils were 0.08-1.47mgkg(-1) for daidzein, ND-78.9μgkg(-1) for daidzin, 0.40-5.89mgkg(-1) for genistein, 1.2-114.9μgkg(-1) for genistin, 3.1-85.0μgkg(-1) for trans-resveratrol and 1.9-51.0μgkg(-1) for cis-resveratrol, which are compatible with the raw materials for oil press. Additionally, the applicability of this method has been successfully tested in thirteen vegetable oils from the market. Mixed-mode SPE LC-MS/MS method can simultaneously detect isoflavones and resveratrols in vegetable oils and assess adulteration and quality of soybean and peanut oils.

TiO₂/SiO₂ core-shell composite-based sample preparation method for selective extraction of phospholipids from shrimp waste followed by hydrophilic interaction chromatography coupled with quadrupole time-of-flight/mass spectrometry analysis

A solid-phase extraction (SPE) procedure, using titania-coated silica (TiO2/SiO2) core-shell composites as the sorbent, combined with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for extraction, visualization, and quantification of phospholipids in shrimp waste (Litopenaeus vannamei). The SPE protocol was optimized, and the best conditions were pH 5 of the loading solvent, 10% aqueous methanol as the washing solvent, and 1.0 mL of chloroform/methanol (1:2, v/v) as eluting solvents. Afterward, the eluate was separated on a diol hydrophilic interaction chromatography (HILIC) column. A total of 69 phospholipid species were identified and determined. The results indicated that, in comparison to previously published methods, this strategy was cost-effective and efficient in extraction, characterization, and determination of phospholipids. Meanwhile, phospholipids were abundant in shrimp waste, most of which contained unsaturated fatty acyl chains, such as 18:3 [α-linolenic acid (ALA)], 20:5 [eicosapentaenoic acid (EPA)], and 22:6 [docosahexaenoic acid (DHA)]. The successful application of this strategy paves the way for full use of traditionally discarded shrimp wastes.