Carbon-13-isotopomics and metabolomics of fatty acids from triacylglycerols: overcoming the limitations of GC-C-IRMS for short- and medium-acyl chains.

Carbon-13 isotopomics of triacylglycerol (TAG) fatty acids or free fatty acids in biological matrices holds considerable potential in food authentication, forensic investigations, metabolic studies, and medical research. However, challenges arise in the isotopic analysis of short- and medium-chain (C4 to C10) fatty acid methyl esters (SMCFAMEs) through gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The high volatility of these esters results in losses during their preparation, leading to isotopic fractionation.

Biomarkers for cheese authentication by detailed and fast gas chromatographic profiling of triacylglycerol fatty acids.

Unsaturated fatty acid isomers and odd- and branched-chain fatty acids (OBCFAs) in milk triacylglycerols (TAGs) can be quantitated using gas chromatography (GC), providing access to biomarkers of animal species, breeds, diet, geographic origin, and environmental conditions. Such analysis requires expensive cyanopropyl siloxane or ionic liquid columns of at least 50 m in length, which increases the elution time. Aiming to use GC for cheese authentication and characterization while keeping the experiment time short and maintaining a good separation between fatty acid (FA) isomers, we considered using a 30 m polyethylene glycol-2-nitroterephthalate column.

Cheese characterization and authentication through lipid biomarkers obtained by high-resolution H NMR profiling.

Food quality and safety are at the heart of consumers' concerns across the world. Dairy products, because of their large consumption, are fertile ground for fraudulent acts. This fact justifies the development of effective, accessible, and rapid analytical methods for their authentication.

Acute limb ischemia and aortic mural thrombosis as primary manifestations of severe acute respiratory syndrome coronavirus 2.

A variable clinical presentation is emerging as a hallmark of the novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). In addition to hypoxic respiratory failure, multiorgan dysfunction, and septic shock, significant thromboembolic complications posited to result from diffuse coagulopathy have been associated with this viral infection. We report on a unique primary manifestation of SARS-CoV-2 infection presenting as acute limb ischemia and aortic mural thrombosis without clinical evidence of pulmonary disease.

EBT3 Gafchromic film as a new substrate for in vitro evaluation of sun protection factor.

There exist different methods for the determination of sun protection factor (SPF) values for sunscreens. We aimed to develop a new in vitro method using EBT3 Gafchromic film as a substrate. The colour of EBT3 Gafchromic film changes when exposed to UV light.

High-resolution H NMR profiling of triacylglycerols as a tool for authentication of food from animal origin: Application to hen egg matrix.

Metabolomics of complex biological matrices conducted by means of H NMR leads to spectra suffering from severe signal overlapping. Previously, we have developed a high-resolution spectral treatment method to help solving this issue in H NMR of triacylglycerols. In this work, we tested the potential of the developed method in the characterization and authentication of food products from animal origin using egg yolk as a model matrix.

A precise and rapid isotopomic analysis of small quantities of cholesterol at natural abundance by optimized H-C 2D NMR.

Cholesterol, the principal zoosterol, is a key metabolite linked to several health complications. Studies have shown its potential as a metabolic biomarker for predicting various diseases and determining food origin. However, the existing INEPT (insensitive nuclei enhanced by polarization transfer) C position-specific isotope analysis method of cholesterol by NMR was not suitable for very precise analysis of small quantities due to its long acquisition time and therefore is restricted to products rich in cholesterol.

Metabisotopomics of triacylglycerols from animal origin: A simultaneous metabolomic and isotopic profiling using C INEPT.

In previous works, we developed a C NMR method for analyzing triacylglycerols in olive oil using an adiabatic refocused INEPT sequence. This allowed spectral acquisition to be done in only 8 min with sufficient precision for isotopic measurements. In the present study, we made use of the same methodology to investigate the potential of triacylglycerols as source of biomarkers in animal origin matrices.

Origanum essential oils reduce the level of melanin in B16-F1 melanocytes.

Background: Hyperpigmentation disorders are considered signs of skin aging and are aesthetically unpleasant. Most active ingredients used against hyperpigmentation disorders predominantly target tyrosinase activity.

Objectives: To study the effect of two Origanum essential oils on the melanogenic activity of B16-F1 murine melanocytes.

Improved lipid mixtures profiling by H NMR using reference lineshape adjustment and deconvolution techniques.

of one-dimensional H NMR spectra of complex mixtures, such as lipids from natural extracts, is hampered by the small spectral width leading to a great number of overlapped signals. Additional complications including lineshape broadening and distortion may occur due to magnetic field inhomogeneity. Quantitation of such spectra is therefore challenging.

Cholesterol, a powerful C isotopic biomarker.

Cholesterol is related to many health diseases and is considered as a metabolic disorder biomarker. This compound, present in all food products of animal origin, can also be used as food authentication biomarker. In this work and for the first time, positional C isotope contents were determined for such a high molecular weight compound.

Phytochemical screening and antityrosinase activity of carvacrol, thymoquinone, and four essential oils of Lebanese plants.

Objective: In our study, we aim to explore the ability of four essential oils (EO) of Lebanese plants to inhibit the tyrosinase activity and to correlate their efficiency level to their phytochemical compositions.

Methods: The EO have been extracted by hydrodistillation using a Clevenger apparatus and have been studied by GC-MS analysis. Active compounds of Origanum species were identified and antityrosinase activities of EO and active molecules (carvacrol and thymoquinone) have been tested in tubo.

Structure, gelation, and antioxidant properties of curcumin-doped casein micelle powder produced by spray-drying.

The encapsulation of curcumin in micellar caseins (MCs) and the production of powder were performed by spray-drying. Nearly 97% of the curcumin was retained and the yellow powder showed a typical high casein powder morphology. The hygroscopic properties were determined, slight differences reflected less available hydrophobic sites when curcumin was bound to casein, favoring interactions with water in curcumin-enriched MC powders.

Olive oil characterization and classification by C NMR with a polarization transfer technique: A comparison with gas chromatography and H NMR.

In a previous work, we optimized and used a fast adiabatic C-INEPT (Insensitive Nuclei Enhanced by Polarization Transfer) experiment for the isotopomic analysis of olive oil samples, which allowed us quantifying individual fatty acids within triacylglycerols through multivariate linear regression models. The goal of this study was to validate these models and to evaluate the power of C-INEPT in the authentication of olive oils relative to gas chromatography (GC) and H NMR. In this respect, a new set of olive oil samples was analyzed by these three techniques.

A strategy for simultaneous determination of fatty acid composition, fatty acid position, and position-specific isotope contents in triacylglycerol matrices by C-NMR.

Triacylglycerols, which are quasi-universal components of food matrices, consist of complex mixtures of molecules. Their site-specific C content, their fatty acid profile, and their position on the glycerol moiety may significantly vary with the geographical, botanical, or animal origin of the sample. Such variables are valuable tracers for food authentication issues.

Geoclimatic, morphological, and temporal effects on Lebanese olive oils composition and classification: A (1)H NMR metabolomic study.

Two hundred and thirty-four Lebanese olive samples were collected from different regions and the corresponding oils were analysed by (1)H NMR spectroscopy. The variables obtained, related to fatty acids and minor components, were used as inputs in univariate and multivariate analyses aiming to characterize and classify the oils according to geographical, morphological, and temporal factors. Samples were sorted according to the colour, size, and shape of olives, which allowed statistically significant classifications to be achieved.

Precise and rapid isotopomic analysis by (1)H-(13)C 2D NMR: Application to triacylglycerol matrices.

An optimized HSQC sequence was tested and applied to triacylglycerol matrices to determine their isotopic and metabolomic profiles. Spectral aliasing and non-uniform sampling approaches were used to decrease the experimental time and to improve the resolution, respectively. An excellent long-term repeatability of signal integrals was achieved enabling to perform isotopic measurements.

Structure and gelation properties of casein micelles doped with curcumin under acidic conditions.

In this study, the ability of micellar casein (MC) to interact with curcumin during acidification and to produce acid gel was investigated. Steady-state fluorescence spectroscopy of curcumin variation and fluorescence quenching of caseins upon binding with curcumin molecules were evidenced. Increasing the temperature from 20 to 35 °C enhanced MC-curcumin interactions as reflected by the increase in the binding constant from 0.

A sharper characterization of the geographical origin of Lebanese wines by a new interpretation of the hydrogen isotope ratios of ethanol.

The hydrogen isotope ratios of the methyl [(D/H)I] and methylene [(D/H)II] groups in ethanol can be used as geographical origin tracers of wines. These ratios reflect not only the deuterium content of sugars but also that of water in the grape medium, and hence are influenced by the irrigation, the degree of ripeness at harvest, and other viticultural and enological practices. Thus, the isotopic redistribution coefficients between water in the grape must and the methyl and methylene sites of ethanol were determined and then used to compute an isotopic ratio [(D/H)Is] representing the contribution of the fermentable sugars to (D/H)I.

Differentiation between Aspergillus flavus and Aspergillus parasiticus from pure culture and aflatoxin-contaminated grapes using PCR-RFLP analysis of aflR-aflJ intergenic spacer.

Aflatoxins (AFs) represent the most important single mycotoxin-related food safety problem in developed and developing countries as they have adverse effects on human and animal health. They are produced mainly by Aspergillus flavus and A. parasiticus.

Occurrence of aflatoxin B1 and ochratoxin A in Lebanese cultivated wheat.

An extensive survey of filamentous fungi isolated from wheat grown and consumed in Lebanon and their capacity to produce aflatoxin B1 (AFB1) and ochratoxin A (OTA) was conducted to assess fungi potential for producing these toxins in wheat. From the 468 samples of wheat kernel, collected at preharvest stage from different locations during 2008 and 2009 cultivation seasons, 3,260 fungi strains were isolated with 49.4% belonging to Penicillium spp.

Calculation of the c(3)a percentage in high sulfur clinker.

The aim of this paper is to clarify the influence of the clinker SO(3) on the amount of C(3)A. The calculation of the cement phases percentages is based on the research work, Calculation of the Compounds in Portland Cement, published by Bogue in 1929 .The usage of high sulphur fuels, industrial wastes, and tires changes completely the working condition of Bogue because the assumed phase compositions may change.

Fungal contamination and Aflatoxin B1 and Ochratoxin A in Lebanese wine-grapes and musts.

Five hundred and ten strains of filamentous fungi were isolated from Lebanese grapes during 2005 at veraison and harvesting periods. Four hundred eighty-seven isolates belonged to the Aspergillus spp. (95.

Occurrence of ochratoxin A- and aflatoxin B1-producing fungi in Lebanese grapes and ochratoxin a content in musts and finished wines during 2004.

This paper reports the results of an extensive survey on the occurrence of filamentous fungi isolated from wine-grapes in Lebanon and to test their ability to produce ochratoxin A (OTA) and aflatoxin B1 (AFB1) on CYA culture medium, in order to assess their potential for producing these mycotoxins on grapes. From the 470 grapes samples taken during season 2004, 550 fungi strains were isolated with 490 belonging to Aspergillus spp. and 60 belonging to Penicillium spp.