Exploring lipid digestion discrepancies between preterm formula and human milk: Insights from in vitro gastrointestinal digestion and the impact of added milk fat.

Lipids play a pivotal role in the nutrition of preterm infants, acting as a primary energy source. Due to their underdeveloped gastrointestinal systems, lipid malabsorption is common, leading to insufficient energy intake and slowed growth. Therefore, it is critical to explore the reasons behind the low lipid absorption rate in formulas for preterm infants. This study utilized a simulated in intro gastrointestinal digestion model to assess the differences in lipid digestion between preterm human milk and various infant formulas. Results showed that the fatty acid release rates for formulas IF3, IF5, and IF7 were 58.90 %, 56.58 %, and 66.71 %, respectively, lower than human milk's 72.31 %. The primary free fatty acids (FFA) and 2-monoacylglycerol (2-MAG) released during digestion were C14:0, C16:0, C18:0, C18:1n-9, and C18:2n-6, in both human milk and formulas. Notably, the higher release of C16:0 in formulas may disrupt fatty acid balance, impacting lipid absorption. Further investigations are necessary to elucidate lipid absorption differences, which will inform the optimization of lipid content in preterm infant formulas.

The potential use of acylglycerols on the thermal inactivation of lactic acid bacteria for the manufacture of long-life fermented products.

The effect of acylglycerols on the thermal inactivation of lactic acid bacteria used in the production of fermented products was studied. The starting point was the observation of an increase in thermal sensitivity in the presence of an emulsifier based on mono- and diacylglycerols in the culture medium. Analysis of the emulsifier showed that monoacylglycerols were the compounds responsible for this effect, with monopalmitin being the main contributor. Monostearin, on the other hand, showed significantly less potentiating effect. Interestingly, monoacylglycerols showed a greater bactericidal effect when used individually than when used in combination. On the other hand, the rate of thermal inactivation observed in reconstituted skim milk emulsions was lower than in peptone water emulsions, showing that the presence of proteins and colloidal particles increased the resistance of bacteria to heat treatment. With respect to pH values, a reduction in pH from 6.6 to 5.5 promoted an increase in the rate of thermal death. However, at pH = 5.5, the enhancing bactericidal effect was only detectable when the heat treatment was performed at low temperatures but not at high temperatures. This finding is of interest, since it will allow the design of moderate heat treatments, combining the use of temperature with the addition of acylglycerols, to prolong the shelf life of products fermented with lactic acid bacteria, and minimizing the destruction of desirable compounds that were obtained by the fermentation process.

Chemical Profile of Lipophilic Fractions of Different Parts of Zizyphus lotus L. by GC-MS and Evaluation of Their Antiproliferative and Antibacterial Activities.

Zizyphus lotus L. is a perennial shrub particularly used in Algerian folk medicine, but little is known concerning the lipophilic compounds in the most frequently used parts, namely, root bark, pulp, leaves and seeds, which are associated with health benefits. In this vein, the lipophilic fractions of these morphological parts of Z. lotus from Morocco were studied by gas chromatography-mass spectrometry (GC-MS), and their antiproliferative and antimicrobial activities were evaluated. GC-MS analysis allowed the identification and quantification of 99 lipophilic compounds, including fatty acids, long-chain aliphatic alcohols, pentacyclic triterpenic compounds, sterols, monoglycerides, aromatic compounds and other minor components. Lipophilic extracts of pulp, leaves and seeds were revealed to be mainly composed of fatty acids, representing 54.3-88.6% of the total compounds detected. The leaves and seeds were particularly rich in unsaturated fatty acids, namely, (9Z,12Z)-octadeca-9,12-dienoic acid (2431 mg kg-1 of dry weight) and (9Z)-octadec-9-enoic acid (6255 mg kg-1 of dry weight). In contrast, root bark contained a high content of pentacyclic triterpenic compounds, particularly betulinic acid, accounting for 9838 mg kg-1 of dry weight. Root bark extract showed promising antiproliferative activity against a triple-negative breast cancer cell line, MDA-MB-231, with a half-maximal inhibitory concentration (IC50) = 4.23 ± 0.18 µg mL-1 of extract. Leaf extract displayed interesting antimicrobial activity against Escherichia coli, methicillin-sensitive Staphylococcus aureus and Staphylococcus epidermis, presenting minimum inhibitory concentration (MIC) values from 1024 to 2048 µg mL-1 of extract. Our results demonstrate that Zizyphus lotus L. is a source of promising bioactive components, which can be exploited as natural ingredients in pharmaceutical formulations.

Characterization of Glucuronosyl-diacyl/monoacylglycerols and Discovery of Their Acylated Derivatives in Tomato Lipid Extracts by Reversed-Phase Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry.

Glucuronic acid containing diacylglycerols (3-(O-α-d-glucuronopyranosyl)-1,2-diacyl-sn-glycerols, GlcA-DAG) are glycolipids of plant membranes especially formed under phosphate-depletion conditions. An analytical approach for the structural characterization of GlcA-DAG in red ripe tomato (Solanum lycopersicum L.) extracts, based on reversed-phase liquid chromatography (RPLC) coupled with electrospray ionization (ESI) and tandem mass spectrometry (MS/MS) using a linear ion trap, is described in this paper. At least 14 GlcA-DAG (R1/R2) species, including four regioisomers, containing three predominant fatty acyl chains C16:0, C18:2, and C18:3, were identified for the first time. Moreover, 29 GlcA-DAG acylated on the glucuronosyl ring (acyl-R3 GlcA-DAG) were discovered, alongside 15 acylated lyso-forms, i.e., acylated 3-(O-α-d-glucuronosyl)monoacylglycerols, abbreviated as acyl-R3 GlcA-MAG (R1/0) or (0/R2). Although many of these acylated lyso-forms were isomeric with GlcA-DAG (i.e., acyl chains with equivalent sum composition), they were successfully separated by reversed-phase liquid chromatography (RPLC) using a solid-core C18 column packed with 2.6 µm particle size. Tandem MS (and eventually MS3) data obtained from sodium adducts ([M + Na]+) and deprotonated molecules ([M - H]-) were fundamental to detect diagnostic product ions related to the glucuronosyl ring and then determine the identity of all investigated glycolipids, especially to recognize the acyl chain linked to the ring. A classification of GlcA-MAG, GlcA-DAG, and acylated GlcA-DAG and GlcA-MAG was generated by an in house-built database. The discovery of acylated derivatives emphasized the already surprising heterogeneity of glucuronic acid-containing mono- and diacylglycerols in tomato plants, stimulating interesting questions on the role played by these glycolipids.

Quantitative Analysis of Polyphosphoinositide, Bis(monoacylglycero)phosphate, and Phosphatidylglycerol Species by Shotgun Lipidomics After Methylation.

Phospholipids play important roles in biological process even at a very low level. For example, bis(monoacylglycerol)phosphate (BMP) is involved in the pathogenesis of lysosomal storage diseases, and polyphosphoinositides (PPI) play critical roles in cellular signaling and functions. Phosphatidylglycerol (PG), a structural isomer of BMP, mediates lipid-protein and lipid-lipid interactions, and inhibits platelet activating factor and phosphatidylcholine transferring. However, due to their low abundance, the analysis of these phospholipids from biological samples is technically challenging. Therefore, the cellular function and metabolism of these phospholipids are still elusive. This chapter overviews a novel method of shotgun lipidomics after methylation with trimethylsilyl-diazomethane (TMS-D) for accurate and comprehensive analysis of these phospholipid species in biological samples. Firstly, a modified Bligh and Dyer procedure is performed to extract tissue lipids for PPI analysis, whereas modified methyl-tert-butylether (MTBE) extraction and modified Folch extraction methods are described to extract tissue lipids for PPI analysis. Secondly, TMS-D methylation is performed to derivatize PG/BMP and PPI, respectively. Then, we described the shotgun lipidomics strategies that can be used as cost-effective and relatively high-throughput methods to determine BMP, PG, and PPI species and isomers with different phosphate position(s) and fatty acyl chains. The described method of shotgun lipidomics after methylation achieves feasible and reliable quantitative analysis of low-abundance lipid classes. The application of this novel method should enable us to reveal the metabolism and functions of these phospholipids in healthy and disease states.

Monoglyceride oleogels as fat replacers in filling creams for sandwich cookies.

BACKGROUND: Many food products need to be reformulated to reduce the intake of saturated and trans fats which are considered unhealthy. In particular, the reformulation of filling creams (FCs) is challenging as these fats cannot be directly replaced with liquid oil without affecting the final product properties. This research studied the formulation and characterization of FCs for sandwich cookies using monoglyceride oleogel as fat material. RESULTS: FC formulated with 260 g kg-1 oleogel showed viscoelastic moduli values that did not differ significantly from those measured in a filling cream of commercial sandwich cookies (FC-CSCs) used as reference. The oil binding capacity of the FCs decreased with the increase of oleogel content. The increase of the oleogel amount in the formulation produced a decrease in hardness but an increase in adhesiveness and cohesiveness. Hardness, adhesiveness, and cohesiveness ranged from 0.66 to 3.48 N, 0.44 to 0.86 N s, and 0.07 to 0.29, respectively. When FCs were used for assembling cookies into sandwiches, an oil loss of about 9 g kg-1 FC after 21 days of storage was found in FCs containing 220 and 260 g kg-1 oleogel. The nutritional improvement due to the use of oleogel in FCs led to a reduction in saturated fatty acids between 64.5% and 35.2% and from 1.0 to 0.0% trans fatty acids in comparison with FC-CSC. CONCLUSION: Full fat replacement with monoglyceride oleogel in FC formulations allows the obtention of products with good quality and some similar characteristics to those obtained for FC-CSC, with the added benefit of a healthier nutritional profile. © 2020 Society of Chemical Industry.

Unveiling the bioactivity of Allium triquetrum L. lipophilic fractions: chemical characterization and in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus.

The lipophilic composition of Allium triquetrum L. bulbs, flowers and leaves was studied for the first time by GC-MS. Sixty compounds were firstly identified in A. triquetrum L. Fatty acids represented the major lipophilic family among the studied extracts, with (9Z,12Z,15Z)-octadeca-9,12,15-trienoic and (9Z,12Z)-octadeca-9,12-dienoic acids being the major constituents of this family. A long chain aliphatic ketone, namely hentriacontan-16-one, was mainly found in flowers and leaves. Flowers and leaves were also found to be rich in long chain aliphatic alkanes and alcohols, respectively. Sterols, monoglycerides, aromatic compounds and long chain aliphatic aldehydes were found in lower amounts. The antibacterial activity of A. triquetrum bulb, flower and leaf extracts against methicillin-resistant Staphylococcus aureus (MRSA) growth was in vitro assessed. Bulb and flower extracts showed significant MRSA growth inhibition. Overall, these valuable findings can contribute to the valorization of A. triquetrum L. as a source of value-added phytochemicals, specifically as antibacterial agents and for nutraceutical applications.

Rapid Raman spectroscopic determination of 1-feruloyl-sn-glycerol and 1,3-diferuloyl-sn-glycerol.

Ferulic acid and its derivatives are important natural products found throughout the plant kingdom and are of special interest due to their health benefits. 1-Feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (F2G) are two common bioproducts of ferulic acid that co-occur in nature and during the biocatalytic production of feruloylated lipids. In this paper, we report a comprehensive characterization of FG and F2G using Raman and UV spectroscopies and theoretical density functional theory calculations at the B3LYP/6-311+G** level. UV spectroscopy produced spectra for FG and F2G with similar peak shape, but difference intensities. The vibrational frequency calculations aided in the assignment of the Raman bands. The Raman analysis demonstrates that Raman spectroscopy is a rapid label free method to clearly distinguish between FG and F2G.

Quantitative molecular tissue atlas of Bis(monoacylglycero)phosphate and phosphatidylglycerol membrane lipids in rodent organs generated by methylation assisted high resolution mass spectrometry.

Bis(monoacylglycero)phosphate (BMP) and phosphatidylglycerol (PG) are structural isomeric phospholipids with very different properties and biological functions. Due to their isomeric nature, it has thus far been challenging to simultaneously quantify BMP and PG lipids in tissue samples by mass spectrometry. Therefore, we have developed a sensitive LC-MS/MS based approach with prior methylation derivatization that is able to handle large batches of samples. Using this high throughput platform, a simulated MS/MS database was established for confident lipid assignment. In this work, we have simultaneously identified and quantified BMP and PG lipid molecules in different body tissues of rats and mice. We report for the first time a quantitative molecular atlas of BMP and PG lipids for 14 different tissues and organs in Wistar rats, NMRI and CD1 mice. Organ- and species-specificity was analyzed and compared for both lipid molecule classes. A total of 34 BMP and 10 PG molecules were quantified, with PG concentrations being generally much higher across tissues than BMP, but BMP lipids showing a much higher molecular diversity between animal organs. The large diversity of the BMP lipids with regard to their abundance and molecular composition suggests distinct biological function(s) of the individual BMP molecules in different tissues and organs of body. Particularly high tissue levels of BMP were seen in spleen, lung, liver, kidney and small intestines, i.e. tissues that are known for their high abundance and/or activity level of lysosomes late and endosomes. Elevated BMP levels in brain tissue of APP/PSEN transgenic compared to age matched wild-type mice were also observed using this platform. This analytical methodology presented a high throughput LC-based approach incorporating simulated MS/MS database to identify and quantify BMP lipids as well as PG molecules.

In-depth lipidomic analysis of tri-, di-, and mono-acylglycerols released from milk fat after in vitro digestion.

Milk fat is arguably one of the most complex fats found in nature and varies widely between animal species. Analysis of its digestion products is tremendously challenging, due to the complexity, diversity, and large range of concentrations of triacylglycerols (TAGs) and their digestion products (i.e. diacylglycerols (DAGs), monoacylglycerols (MAGs), and free fatty acids (FFAs)). Therefore, a method combined the solid phase extraction (SPE), high-performance liquid chromatography (HPLC) and multi-dimension mass spectrometry (MDMS) was developed to identify and semi-quantify the TAGs, DAGs and MAGs in milk fat after in vitro digestion. Up to 105, 64, 14 and 30 species of TAGs, DAGs, MAGs, and FFAs were determined with their concentrations of 0.01-22.3, 0.01-39.2, 0.01-47.8, and 0.04-191.0 mg/g fat, respectively, during the in vitro digestion of cow and sheep milk. The validation of the method shows that this method was precise and reliable.

Metabolite aberrations in early diabetes detected in rat kidney using mass spectrometry imaging.

Diabetic kidney disease is a serious complication of diabetes that can ultimately lead to end-stage renal disease. The pathogenesis of diabetic kidney disease is complex, and fundamental research is still required to provide a better understanding of the driving forces behind it. We report regional metabolic aberrations from an untargeted mass spectrometry imaging study of kidney tissue using an insulinopenic rat model of diabetes. Diabetes was induced by intravenous injection of streptozotocin, and kidneys were harvested 2 weeks thereafter. Imaging was performed using nanospray desorption electrospray ionization connected to a high-mass-resolving mass spectrometer. No histopathological changes were observed in the kidney sections; however, mass spectrometry imaging revealed a significant increase in several 18-carbon unsaturated non-esterified fatty acid species and monoacylglycerols. Notably, these 18-carbon acyl chains were also constituents of several increased diacylglycerol species. In addition, a number of short- and long-chain acylcarnitines were found to be accumulated while several amino acids were depleted. This study presents unique regional metabolic data indicating a dysregulated energy metabolism in renal mitochondria as an early response to streptozotocin-induced type I diabetes. Graphical abstract.

Prediction of oxidative stability in bulk oils using dielectric constant changes.

The effects of amphiphilic compounds on the dielectric constant of bulk oils were determined and the utility of the dielectric constant as a reliable parameter for predicting the oxidative stability of edible oils was evaluated. As the content of monoacylglycerols (MAGs), lecithin, and moisture increased, the dielectric constant of modified corn oil increased at different rates, whereas the addition of free fatty acids, including oleic and linoleic acid, decreased the dielectric constant of modified corn oil. Unoxidized fresh bulk oils showed a wide range of dielectric constants, from 8 for canola oils to 33 for flaxseed oils. The dielectric constant showed a strong correlation with the percentage of unsaturated fatty acids in the bulk oils. Oils with low oxidative stability had a high dielectric constant. Overall, the dielectric constant of bulk oils is strongly correlated with the content of amphiphilic compounds, moisture content, and degree of unsaturation of fatty acids.

Monoacylglycerol and diacylglycerol production by hydrolysis of refined vegetable oil by-products using an immobilized lipase from Serratia sp. W3.

Unlike the synthetic surfactants, mono- and diacylglycerols have the advantage to be biodegradable and non-toxic. In the present work, the hydrolysis of lipid fraction by-products of refined vegetable oils was performed by Serratia sp. W3 lipase immobilized on CaCO3 by combined adsorption and precipitation. This support was selected out of four carriers as it exhibited the finest activity support (950 U/g) and the most satisfactory behavior at use. The immobilized preparation with CaCO3 was stable and active in the whole range of pH (4 to 9) and temperature (37 to 55°C), yielding a 75% degree of hydrolysis at optimal environmental conditions of pH 8.5 and temperature 55°C. Thin-layer chromatography, gas chromatography, and liquid chromatography methods were evaluated to determine the analytical characterization of hydrolysis products. For monoacylglycerols and diacylglycerol fractions identified in the samples, a novel approach by liquid chromatography method was employed, through a homemade linear retention index database and a dedicated software. The adopted approach allowed the use of basic instrumentation set-ups, without the need of sophisticated detectors, such as mass spectrometers. Thus, it could be an effective alternative to produce emulsifiers from cheap vegetable oils.

High-Performance Thin-Layer Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry for Identifying Neutral Lipids and Sphingolipids in Complex Samples.

High-performance thin-layer chromatography was directly combined with electrospray mass spectrometry (ESI-MS) for structural identification issues below the level of lipid classes in complex samples through a portable, automated, elution-based interface. For samples as diverse as biodiesel and human plasma, separation conditions using Automated Multiple Development were selected in each case to provide lipid classes as zones narrow enough to ensure a direct transfer of them to ESI-MS. The respective zone of interest can be selected at will. ESI+ spectra of neutral lipids and sphingolipids showed sodium adducts when recorded from the plate. By using the described technique and ion-trap technology, the respective sodium adducts were fragmented. Sodium remained as the charge of the fragment ions and, thus, was useful for their structural identification through MSn. In this way, composition profiles of each class by ESI+-MS, and further identification of individual lipids and the molecular species belonging to each of them, were obtained by MS/MS and/or high-resolution MS. Thus, mono and diacylglycerides in ESI+ and fatty acids (in ESI-) were identified as low-concentration impurities in a fatty acid methyl ester-based biodiesel sample. Likewise, molecular species of sphingomyelins and globotriaosylceramides were unequivocally identified in human plasma samples.

Production of FAME and FAEE via Alcoholysis of Sunflower Oil by Eversa Lipases Immobilized on Hydrophobic Supports.

The performance of two new commercial low-cost lipases Eversa® Transform and Eversa® Transform 2.0 immobilized in different supports was investigated. The two lipases were adsorbed on four different hydrophobic supports. Interesting results were obtained for both lipases and for the four supports. However, the most active derivative was prepared by immobilization of Eversa® Transform 2.0 on Sepabeads C-18. Ninety-nine percent of fatty acid ethyl ester was obtained, in 3 h at 40 °C, by using hexane as solvent, a molar ratio of 4:1 (ethanol/oil), and 10 wt% of immobilized biocatalyst. The final reaction mixture contained traces of monoacylglycerols but was completely free of diacylglycerols. After four reaction cycles, the immobilized biocatalyst preserved 75% of activity. Both lipases immobilized in Sepabeads C-18 were very active with ethanol and methanol as acceptors, but they were much more stable in the presence of ethanol.

Insights into the MALDI Process after Matrix Deposition by Sublimation Using 3D ToF-SIMS Imaging.

Imaging mass spectrometry (IMS) has become a powerful tool to characterize the spatial distribution of biomolecules in thin tissue sections. In the case of matrix-assisted laser desorption ionization (MALDI) IMS, homogeneous matrix deposition is critical to produce high-quality ion images, and sublimation in particular has shown to be an excellent matrix deposition method for the imaging of lipids. Matrix deposition by sublimation is, however, a completely solvent-free system, which ought to prevent the mixing of matrix and analytes thought to be necessary for successful MALDI. Using 3D time-of-flight secondary ion imaging mass spectrometry, we have studied the matrix-tissue interface in 3D with high resolution to understand the MALDI process of lipids after matrix deposition by sublimation. There is a strong indication that diffusion is the process by which lipids migrate from the tissue to the matrix layer. We show that triacylglycerols and phospholipids have a delayed migratory trend as compared to diacylglycerols and monoacylglycerols, which is dependent on time and matrix thickness. Additional experiments show that a pure lipid's capacity to migrate into the matrix is dependent on its fluidity at room temperature. Furthermore, it is shown that cholesterol can only migrate in the presence of a (fluid) lipid and appears to fluidize lipids, which could explain its colocalization with the diacylglycerols and monoacylglycerols in the matrix.

Investigation of Silver Nanoparticle Induced Lipids Changes on a Single Cell Surface by Time-of-Flight Secondary Ion Mass Spectrometry.

Lipids are the main component of the cell membrane. They not only provide structural support of cells but also directly participate in complex cellular metabolic processes. Lipid signaling is an important part of cell signaling. Evidence showed that abnormal cellular metabolism may induce lipids changes. Besides, owing to single cell heterogeneity, it is necessary to distinguish different behaviors of individual cells. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a sensitive surface analysis technique with high spatial resolution, which is useful in single cell surface analysis. Herein, we used ToF-SIMS to investigate silver nanoparticle induced lipids changes on the surface of single macrophage cells. Delayed extraction mode of ToF-SIMS was used to simultaneously obtain high mass resolution of mass spectra and high spatial resolution of single cell chemical imaging. Principle component analysis (PCA) results showed good agreement with the cytotoxicity assay results. Clear distinctions were observed between the cell groups treated with high or low dose of silver nanoparticles. The loadings plots revealed that the separation was mainly due to changes of cholesterol and diacylglycerol (DAG) as well as monoacylglycerol (MAG). Meanwhile, the chemical mapping of single cell components showed that cholesterol and DAG tend to migrate to the surrounding of the cells after high dose silver nanoparticles (Ag NPs) treatment. Our results demonstrated the feasibility of ToF-SIMS for characterizing the changes of the lipids on a single cell surface, providing a better understanding of the mechanism of cell-nanoparticle interactions at the molecular level.

Mass spectrometric imaging of localization of fat molecules in water-in-oil emulsions containing semi-solid fat.

Firstly, we report the localization analysis of the lipid components of a water-in-oil (W/O) semi-solid emulsion by mass spectrometry imaging (MSI). Uniform emulsion droplets were prepared using microchannel emulsification devices with lecithin, stearic acid-binding monoglyceride (St-MAG), and polyglycerol polyricinoleate (PGPR) as emulsifiers. The mass image gives us the localization of phosphatidylcholine (PC) in lecithin, St-MAG, tripalmitin (PPP), medium-chain triglyceride (MCT), and high-melting-point triglyceride tristearin (C18-TAG). PC, St-MAG, and PPP were localized at the interface with the dispersed water droplets. PC and PPP took the same localized position, suggesting an interaction between PC and PPP at the interface. Conversely, PC existed in other regions with St-MAG. MSI revealed multiple target molecules in fat products in a single measurement, and it is expected to reveal fat crystallization at the emulsion interfaces, which will clarify the mechanisms related to the physical properties of high-fat products such as fat spread and butter.

Strategy for Quantitative Analysis of Isomeric Bis(monoacylglycero)phosphate and Phosphatidylglycerol Species by Shotgun Lipidomics after One-Step Methylation.

Understanding the cellular function and metabolism of bis(monoacylglycero)phosphate (BMP), an important but low-abundance class of phospholipids, has been hindered due to its difficulties to be resolved from its structural isomer (i.e., phosphatidylglycerol, PG, another low-abundance class of phospholipids). A novel strategy for quantitative analysis of BMP and PG species was developed after one-step methylation of lipid extracts in combination with high mass accuracy/resolution mass spectrometry after direct infusion (i.e., shotgun lipidomics). The novel strategy was applied for quantitative analysis of mouse hepatic BMP and PG species and their changes induced by long-term high-fat diet (HFD) feeding. Interestingly, we revealed that HFD-fed mice display a dramatic accumulation of hepatic BMP compared to chow-fed littermates. We believe the development of this novel strategy could greatly facilitate our understanding of the role of BMP in biological systems.

Modified Gas Chromatographic Method to Determine Monoacylglycerol and Diacylglycerol Contents in Edible Fats and Oils.

Monoacylglycerol (MAG) and diacylglycerol (DAG) are minor components of edible fats and oils, and they relate to the quality of these foods. The AOCS official method Cd 11b-91 has been used to determine MAG and DAG contents in fats and oils. There are, however, difficulties in the determination of MAG and DAG using this analytical procedure. Therefore, we improved this method by modifying the trimethylsilyl derivatization procedure and replacing the internal standard (IS) material. In our modified method, TMS-HT (mixture of hexamethyldisilazane and trimethylchlorosilane) was used for derivatization of MAG and DAG, which was followed by liquid-liquid extraction with water and n-hexane solution containing the IS, tricaprin. Using the modified method, we demonstrated superior repeatability in comparison with that of the AOCS method by reducing procedural difficulties. The relative standard deviation of distearin peak areas was 1.8% or 2.9% in the modified method, while it was 5.6% in the AOCS method. In addition, capillary columns, such as DB-1ht and DB-5ht could be used in this method.