Fatty Acid Isomers Research Articles

Identification and quantitation of carbon–carbon double bond isomers of fatty acid in livestock and poultry meat

Livestock and poultry meat is one of the main consumption sources of fatty acids (FAs) in China. FAs are the main component of lipids and essential nutrients for the human body. The location of carbon–carbon double bond (CC) in unsaturated fatty acids (UFAs) significantly affects the nutrition and flavor quality of meat products. This study established an analytical method for identifying the CC positions of UFAs based on the Paternò-Büchi (PB) reaction using ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF). The FA extract was derivatized with 2-acetylpyridine under ultraviolet light at 254 nm. The derivatized FA was then analyzed using targeted MS/MS mode in positive electrospray ionization. Limits of detection (LOD) and limits of quantitation (LOQ) of 21 UFAs were 0.004–0.680 and 0.013–2.267 μg/L, respectively. Furthermore, for the diagnostic ions at the same functional group terminal fragmented from derivatives of FA CC isomers, the abundance ratio was linear with that of the corresponding content, which could be applied to non-targeted screening of CC positions in FAs. Based on this method, a total of 28 UFAs were screened in five types of livestock and poultry meats in this study. Among them, four isomers of C17:1, four of C18:1, two of C18:2, two of C20:3 and two of C22:5 were identified. The precise identification and quantitation of the double bond positions of fatty acids will be of great significance for the exploration of the nutritional components in livestock and poultry meat.

Supercritical fluid chromatography- Nanospray ionization-mass spectrometry (SFC-nSI-MS)

A nanospray emitter coupled to a supercritical fluid chromatograph (SFC-nSI-MS) for mass spectrometric (MS) analysis of fatty acids (FA) positional isomers is introduced. The experimental setup uses conventional bore columns before the SF back-pressure regulator (pre-BPR). The flow is then split and nanosprayed using a short emitter post-BPR. A C18 column was used to resolve positional isomers of unsaturated FA with a 5 min gradient. Chromatographic resolution of the nSFC was compared to a LC-MS system with superior resolving power demonstrated in the nSFC MS system. This system has proven quantitative performance for analyzing pharmaceutical effects on FA composition in a complex biological matrix like E coli lysate.

LC–MS/MS-based phospholipid profiling of plant-pathogenic bacteria with tailored separation of methyl-branched species

Plant-pathogenic bacteria are one of the major constraints on agricultural yield. In order to selectively treat these bacteria, it is essential to understand the molecular structure of their cell membrane. Previous studies have focused on analyzing hydrolyzed fatty acids (FA) due to the complexity of bacterial membrane lipids. These studies have highlighted the occurrence of branched-chain fatty acids (BCFA) alongside normal-chain fatty acids (NCFA) in many bacteria. As several FA are bound in the intact phospholipids of the bacterial membrane, the presence of isomeric FA complicates lipid analysis. Furthermore, commercially available reference standards do not fully cover potential lipid isomers. To address this issue, we have developed a reversed-phase high-performance liquid chromatography (RP-HPLC) method with tandem mass spectrometry (MS/MS) to analyze the phospholipids of various plant-pathogenic bacteria with a focus on BCFA containing phospholipids. The study revealed the separation of three isomeric phosphatidylethanolamines (PE) depending on the number of bound BCFA to NCFA. The validation of the retention order was based on available reference standards in combination with the analysis of hydrolyzed fatty acids through gas chromatography with mass spectrometry (GC/MS) after fractionation. Additionally, the transferability of the retention order to other major lipid classes, such as phosphatidylglycerols (PG) and cardiolipins (CL), was thoroughly examined. Using the information regarding the retention behavior, the phospholipid profile of six plant-pathogenic bacteria was structurally elucidated. Furthermore, the developed LC–MS/MS method was used to classify the plant-pathogenic bacteria based on the number of bound BCFA in the phospholipidome.Graphical

Hygienic assessment of dietary intake of saturated fatty acids and trans isomers of fatty acids

Introduction. An imbalance of the fat component of the diet is one of the most common violations of the population nutrition in developed countries, leading to the risk of occurring nutrition-dependent pathologies due to hyperlipidemia and dyslipoproteinemia. A special role in the formation of risk is played by an excess of medium-chain saturated fatty acids (SFA) and trans isomers of unsaturated fatty acids (TFA). Materials and methods. Actual nutrition was studied by reproduction method with three times 24-hour recall. Based on the research results, the content of SFA and TFA was calculated, and their main sources were determined. Three hundred fourteen students of the I.M. Sechenov First Moscow State Medical University took part in the study. Gender and age groups of respondents were analyzed separately. Results. The intake of SFA at the level of normal physiological needs was registered in only 7.6% of students. At the same time, 80% of respondents had a significant excess of both total fat and SFA; an adequate level of TFA intake was noted in 80% of students, and a significant excess of this indicator was registered only in 13.3% of respondents. A significant quantitative increase in SFAs was noted with the additional inclusion of processed products in the diet, including those with hidden fat. Excessive consumption of TFA is associated with the inclusion of rich confectionery products containing hydrogenated fats in the diet. Limitations. The study has age and regional restrictions: young 18–29 years people living in the Moscow region, as well as restrictions on the analyzed indicators: SFA and TFA supplied with the diet. Conclusions. A significant risk of developing nutrition-dependent non-infectious diseases is observed in 52.9% of respondents with an SFA content in the diet of more than 150% of the norm, and the maximum risk is in 13.3% of students receiving a combined excess of SFA and TFA. The results of the study confirm the need to correct the diets of students in terms of the fat component.

Сучасний стан законодавчого регулювання вмісту транс-ізомерів жирних кислот у харчових продуктах в Україні та світі (огляд літератури)

Abstract. The influence of fats and oils on human health is in constant attention of leading experts in the field of public health, of both national and international institutions. This is especially true concerning industrially obtained trans fats and their regulation. Currently, in Ukraine, the requirements for the content of trans fatty acids in food products are regulated by documents of two levels. Firstly, the requirements for the content of trans fatty acids in certain types of oil and fat products are set out in the national standards (DSTU), which are do not cover the entire range of fat-containing products. Secondly, a norm on limiting the amount of trans fatty acids in food products was adopted in Section V of the Order of the Ministry of Health of Ukraine dated July 16, 2020 No. 1613 “On Approval of the Rules for Adding Vitamins, Mineral Substances and Certain Other Substances to Food Products”, which is harmonized with European legislation, but this norm will be valid only three years after the entry of this order into force in 2023. Aim. To review the scientific literature on the effects of trans fats on human health. To study and generalize the approaches to limiting the consumption of trans fatty acids in different countries of Europe and world. To compare international and Ukrainian legislation on the regulation of trans fatty acids in food products. Materials and Methods. The article uses information based on the materials of FAO/WHO experts, on legislation regulating trans fatty acids in food products, as well as on publications of foreign and Ukrainian scientists. The results of our own studies of the content of trans fats in some foods were compared with data obtained in other countries. Results and Conclusions. Summarizing the results of numerous studies convincingly prove the relationship between the consumption of industrial trans fats with the risk of occurrence or exacerbation of existing nutritional diseases. Best practice policies to eliminate industrially produced trans fatty acids from national food stocks have been introduced in more than forty countries around the world. In Ukraine, food restrictions on the amount of trans fatty acids, which are not trans fatty acids naturally found in fats of animal origin, at a level of no more than 2 %, came into force in September 2023. In this regard, we consider it necessary to apply large-scale educational campaigns of a high scientific level in the media regarding the harmful effects of trans fats on the biological systems of the human body. In addition, we recommend the introduction of state programs in the field of dietary regulation into the practice of general educational institutions, contributing to a conscious and responsible approach to the transition to a healthy diet, which will contribute to a gradual increase in the life expectancy of the population of our country. Keywords: trans fatty acid isomers, public health, harmonization, review.

Position-specific isomers of monohydroxy fatty acids in the land-atmosphere interface: identification and quantification

Due to a wide variety and similar physicochemical properties of monohydroxy saturated fatty acids (OH-FAs) isomers as biomarkers, previously reported OH-FAs in environmental samples were mainly restricted to the α-, β-, (ω-1)- and ω-OH-FA isomers. Here, N,N-dimethylethylenediamine (DMED) labeling coupled with ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) analysis with multiple reaction monitoring mode (MRM) was developed to screen, identify and quantify position-specific isomers of OH-FAs (C8-C18). An identification strategy of positional isomers of OH-FAs, including α-, β-, 4 to (ω-2)-, (ω-1)- and ω-OH-FAs, was established by integrating the characteristics of peak intensity ratios of product ions based on the library of OH-FAs. Meanwhile, d4-DMED-labeled OH-FA standards as internal standards were adopted for the relative quantification of positional isomers. The extraction processes were optimized for different interface-environmental samples. Our method offers a promising tool to investigate position-specific isomers of OH-FAs in the land-atmosphere interface.

Identification of Conjugated Dienes of Fatty Acids in Vischeria sp. IPPAS C-70 under Oxidative Stress.

The microalgae Vischeria sp. IPPAS C-70 produces eicosapentaenoic acid. Several stresses cause the formation of fatty acid peaks that resemble hexadecadienoic acids. We used the integrated technique including TLC, HPLC, and GC-MS to search and determine these fatty acids. Double bond positioning in these fatty acids indicated that they were conjugated dienes and allenes. We identified and described natural nine isomers of C16 polyunsaturated fatty acids, including common methylene-interrupted dienes (Δ6,9-16:2, Δ7,10-16:2, Δ9,12-16:2), and unusual conjugated dienes (Δ6,8-, Δ7,9-, Δ8,10-, Δ9,11-, and Δ10,12-16:2), as well as allenic diene (Δ9,10-16:2). We hypothesize that the formation of conjugated dienes and allenes among fatty acids is the result of oxidative stress caused by H2O2. Hydrogen peroxide also caused an increase in saturated at the expense of unsaturated fatty acids, suggesting inhibition either fatty acid desaturases activities or the corresponding gene expression.

Trans isomeric fatty acids in human milk and their role in infant health and development.

It is well known that long chain polyunsaturated fatty acids (LCPUFAs) play an important role in neurodevelopment in the perinatal life. The most important source of these fatty acids is the diet, however, they can also be formed in the human body from their shorter chain precursors, the essential fatty acids. Since the WHO recommends exclusive breastfeeding for the first six months after birth, the exclusive source of these fatty acids for breastfed infants is human milk, which can be influenced by the mother's diet. Unsaturated fatty acids can have either cis or trans configuration double bond in their chain with distinct physiological effects. Cis isomeric unsaturated fatty acids have several beneficial effects, while trans isomers are mostly detrimental, because of their similar structure to saturated fatty acids. Trans fatty acids (TFAs) can be further subdivided into industrial (iTFA) and ruminant-derived trans fatty acids (rTFA). However, the physiological effects of these two TFA subgroups may differ. In adults, dietary intake of iTFA has been linked to atherosclerosis, insulin resistance, obesity, chronic inflammation, and increased development of certain cancers, among other diseases. However, iTFAs can have a negative impact on health not only in adulthood but in childhood too. Results from previous studies have shown that iTFAs have a significant negative effect on LCPUFA levels in the blood of newborns and infants. In addition, iTFAs can affect the growth and development of infants, and animal studies suggest that they might even have lasting negative effects later in life. Since the only source of TFAs in the human body is the diet, the TFA content of breast milk may determine the TFA supply of breastfed infants and thus affect the levels of LCPUFAs important for neurodevelopment and the health of infants. In this review, we aim to provide an overview of the TFA content in human milk available in the literature and their potential effects on infant health and development.

The intracellular growth of the vacuolar pathogen Legionella pneumophila is dependent on the acyl chain composition of host membranes

Legionella pneumophila is an accidental human bacterial pathogen that infects and replicates within alveolar macrophages causing a severe atypical pneumonia known as Legionnaires’ disease. As a prototypical vacuolar pathogen L. pneumophila establishes a unique endoplasmic reticulum (ER)-derived organelle within which bacterial replication takes place. Bacteria-derived proteins are deposited in the host cytosol and in the lumen of the pathogen-occupied vacuole via a type IVb (T4bSS) and a type II (T2SS) secretion system respectively. These secretion system effector proteins manipulate multiple host functions to facilitate intracellular survival of the bacteria. Subversion of host membrane glycerophospholipids (GPLs) by the internalized bacteria via distinct mechanisms feature prominently in trafficking and biogenesis of the Legionella-containing vacuole (LCV). Conventional GPLs composed of a glycerol backbone linked to a polar headgroup and esterified with two fatty acids constitute the bulk of membrane lipids in eukaryotic cells. The acyl chain composition of GPLs dictates phase separation of the lipid bilayer and therefore determines the physiochemical properties of biological membranes - such as membrane disorder, fluidity and permeability. In mammalian cells, fatty acids esterified in membrane GPLs are sourced endogenously from de novo synthesis or via internalization from the exogenous pool of lipids present in serum and other interstitial fluids. Here, we exploited the preferential utilization of exogenous fatty acids for GPL synthesis by macrophages to reprogram the acyl chain composition of host membranes and investigated its impact on LCV homeostasis and L. pneumophila intracellular replication. Using saturated fatty acids as well as cis- and trans- isomers of monounsaturated fatty acids we discovered that under conditions promoting lipid packing and membrane rigidification L. pneumophila intracellular replication was significantly reduced. Palmitoleic acid – a C16:1 monounsaturated fatty acid – that promotes membrane disorder when enriched in GPLs significantly increased bacterial replication within human and murine macrophages but not in axenic growth assays. Lipidome analysis of infected macrophages showed that treatment with exogenous palmitoleic acid resulted in membrane acyl chain reprogramming in a manner that promotes membrane disorder and live-cell imaging revealed that the consequences of increasing membrane disorder impinge on several LCV homeostasis parameters. Collectively, we provide experimental evidence that L. pneumophila replication within its intracellular niche is a function of the lipid bilayer disorder and hydrophobic thickness.

Определение взаимосвязи генотипов SNP с содержанием жирных кислот различной пространственной конфигурации в молоке коров

Abstract. Milk fat is the third main source of lipids for human nutrition. Fatty acids in milk fat have a heterogeneous composition due to differences in chain length, degree of saturation, etc. It has been scientifically proven that long-term consumption of trans-fatty acids causes various diseases of the human body; according to WHO recommendations, their maximum consumption should not exceed 1 % of total energy. A comprehensive study of the composition of fatty acids in cattle milk gives scientists the opportunity to use this trait in breeding work by selecting genotypes with a low content of trans-isomers and saturated fatty acids harmful to human health. The scientific novelty lies in the study of molecular genetic mechanisms for regulating the quantitative content of fatty acids and their trans-isomers in the fat fraction of cow's milk. The purpose of the work is to identify allelic variants of SNPs associated with the fatty acid composition of cow's milk and the content of trans isomers of unsaturated fatty acids in it. Research methods. The studies were carried out on cows of the Holstein black-and-white breed. The genetic profile of animals of the Holstein black-and-white breed was studied, SNPs significantly associated with the quantitative and qualitative content of fatty acids and their trans-isomers in the fat fraction of cow's milk were identified. The fatty acid composition of cows' milk was determined using a multiparameter automatic analyzer MilkoScan 7/Fossomatic 7 FT+ / DC (FOSS, Denmark). Results. Whole-genome genotyping was performed. Analyzing the content of fatty acids with different saturation of hydrogen bonds, a significant difference between the amount of fatty acids and genotypes, reliable values were established only for 5 SNPs. It was found that for four SNPs, the highest values of the content of fatty acids and trans-isomers were in homozygous genotypes ARS-BFGL-NGS-41348GG; BTA-115852-no-rsAA; BTB-00771463GG; Hapmap46159-BTA-70956TT. A significant difference in the content of trans-fatty acid isomers in milk between genotypes was found only for SNP ARS-BFGL-NGS-5502. The largest mass fraction of trans-isomers of unsaturated fatty acids was found in the milk fat of cows with the heterozygous genotype AG, which amounted to 0.076 g/100 g and was 0.011 g/100 g and 0.032 g/100 g (P≤0.01) more compared to heterozygous genotypes GG and AA, respectively.

Exploring the Influence of the Selected Conjugated Fatty Acids Isomers and Cancerous Process on the Fatty Acids Profile of Spleen

The spleen, traditionally associated with blood filtration and immune surveillance, has recently been recognized for its role in systemic lipid metabolism and potential influence on cancer development and progression. This study investigates effects of dietary supplements, specifically conjugated linolenic acids from pomegranate seed oil and bitter melon extract, on the fatty acid (FA) composition of the spleen in the context of cancerous processes. Advanced methods, including gas chromatography–mass spectrometry and silver ion-impregnated high-performance liquid chromatography, were employed to analyze the spleen’s FA profile. Our research uncovered that dietary supplementation leads to alterations in the spleen’s FA profile, especially under the carcinogenic influence of 7,12-dimethylbenz[a]anthracene. These changes did not align with a simple protective or anti-carcinogenic pattern, as previously suggested in in vitro studies. We observed shifts in conjugated FA isomer concentrations and variations in desaturase activities, suggesting disrupted lipid metabolism in cancerous conditions. The findings underscore the spleen’s vital role in lipid metabolism within the body’s systemic health framework, highlighting the complexity of dietary supplements’ impact on FA profiles in the spleen and their potential implications in cancer progression and treatment. This study adds valuable insight into the complex interplay between diet, disease, and metabolic regulation, particularly in cancerous environments.

Research Progress on the Mechanism of Milk Fat Synthesis in Cows and the Effect of Conjugated Linoleic Acid on Milk Fat Metabolism and Its Underlying Mechanism: A Review.

Milk fat synthesis in cows mainly includes the synthesis of short- and medium-chain fatty acids, the uptake, transport, and activation of long-chain fatty acids (LCFAs), the synthesis of triglycerides, and the synthesis of the genes, transcription factors, and signaling pathways involved. Although the various stages of milk fat synthesis have been outlined in previous research, only partial processes have been revealed. CLA consists of an aggregation of positional and geometric isomers of linoleic fatty acid, and the accumulated evidence suggests that the two isomers of the active forms of CLA (cis-9, trans-11 conjugated linoleic acid and trans-10, cis-12 conjugated linoleic acid, abbreviated as c9, t11-CLA and t10, c12-CLA) can reduce the fat content in milk by regulating lipogenesis, fatty acid (FA) uptake, oxidation, and fat synthesis. However, the mechanism through which CLA inhibits milk fat synthesis is unique, with most studies focusing only on the effects of CLA on one of the genes, transcription factors, or signaling pathways involved. In this study, we summarized the structure and function of classic genes and pathways (mTOR, SREBP, AMPK, and PPARG) and new genes or pathways (THRSP, METTL3, ELOVL, and LPIN1) involved in each stage of milk fat synthesis and demonstrated the interactions between genes and pathways. We also examined the effects of other substances (melanin, nicotinic acid, SA, etc.). Furthermore, we evaluated the influence of β-sitosterol, sodium butyrate, Met arginine, and Camellia oleifera Abel on milk fat synthesis to improve the mechanism of milk fat synthesis in cows and provide a mechanistic reference for the use of CLA in inhibiting milk fat biosynthesis.

Fatty acid isomerism: analysis and selected biological functions.

The biological functions of fatty acids and the lipids in which they are esterified are determined by their chain length, double bond position and geometry and other structural motifs such as the presence of methyl branches. Unusual isomeric features in fatty acids of human foods such as conjugated double bonds or chain branching found in dairy products, some seeds and nuts, and marine foods potentially have important effects on human health. Recent advancements in identifying fatty acids with unusual double bond positions and pinpointing the position of methyl branches have empowered the study of their biological functions. We present recent advances in fatty acid structural elucidation by mass spectrometry in comparison with the more traditional methods. The double bond position can be determined by purely instrumental methods, specifically solvent-mediated covalent adduct chemical ionization (SM-CACI) and ozone induced dissociation (OzID), with charge inversion methods showing promise. Prior derivatization using the Paternò-Büchi (PB) reaction to yield stable structures that, upon collisional activation, yield the double bond position has emerged. The chemical ionization (CI) based three ion monitoring (MRM) method has been developed to simultaneously identify and quantify low-level branched chain fatty acids (BCFAs), unattainable by electron ionization (EI) based methods. Accurate identification and quantification of unusual fatty acid isomers has led to research progress in the discovery of biomarkers for cancer, diabetes, nonalcoholic fatty liver disease (NAFLD) and atherosclerosis. Modulation of eicosanoids, weight loss and the health significance of BCFAs are also presented. This review clearly shows that the improvement of analytical capacity is critical in the study of fatty acid biological functions, and stronger coupling of the methods discussed here with fatty acid mechanistic research is promising in generating more refined outcomes.

Structural Elucidation and Relative Quantification of Fatty Acid Double Bond Positional Isomers in Biological Tissues Enabled by Gas-Phase Charge Inversion Ion/Ion Reactions.

Fatty acids (FAs) contain a vast amount of structural diversity, and differences in fatty acid structure have been associated with various disease states. Accurate identification and characterization of fatty acids is critical to fully understand the biochemical roles these compounds play in disease progression. Conventional tandem mass spectrometry (MS/MS) workflows do not provide sufficient structural information, necessitating alternative dissociation methods. Gas-phase charge inversion ion/ion reactions can be used to alter the ion type subjected to activation to provide improved or complementary structural information. Herein, we have used an ion/ion reaction between fatty acid (FA) anions and magnesium tris-phenanthroline [Mg(Phen)3] dications to promote charge remote fragmentation of carbon-carbon bonds along the fatty acid chain, allowing for localization of carbon-carbon double bond (C=C) positions to successfully differentiate monounsaturated fatty acid isomers. Relative quantification was also performed to obtain the relative abundance of fatty acid isomers in different biological tissues. For example, the relative abundance of FA 18:1 (9) was determined to vary across regions of rat brain, rat kidney, and mouse pancreas, and FA 16:1 (9) was found to have a higher relative abundance in the dermis layer compared to the sebaceous glands in human skin tissue.

Obtaining target dietary fats in the technology of step-by-step hydrogenation and their use

Introduction: Fats are an important component of a number of food products and affect their consistency, shelf life, taste, and nutritional qualities. Step-by-step hydrogenation is one of the main methods of modifying dietary fats, which allows for influencing their chemical structure and properties. The purpose of this study was to establish the main approaches to the step-by-step hydrogenation of dietary fats, the problems of the method, the main areas of use, and prospects for improving the technology. Material and Methods: A search to identify relevant papers was conducted for sources using open electronic databases, such as Google Scholar, Scopus, and Web of Science. Results and Discussion: During the study, the most common conditions of the hydrogenation reaction were established. The most important characteristics of the catalyst were determined by the activity, durability, selectivity, and stability of the formation of isomers. The formation of trans isomers of fatty acids, which reduces the quality of fat, has been identified as the main disadvantage of step-by-step hydrogenation. Factors contributing to the formation of trans isomers included high temperature, catalyst properties, and high content of unsaturated fatty acids in the feedstock. Step-by-step hydrogenation was identified to be the most characteristic of the soybean industry and for the production of confectionery and baking fats with specified properties. Conclusion: The results obtained indicate the potential of step-by-step hydrogenation to produce edible fats with a certain melting point and organoleptic characteristics after solving the cis/trans-isomerisation problem.

PSI-20 Trans Vaccenic Acid Does Not Improve Insulin Resistance in Diet Induced Obese Mice

Abstract Trans vaccenic acid (TVA, trans11-18:1) is a natural trans fatty acid that is exclusively found in ruminant fats such as dairy, beef, and lamb. Increased circulating concentrations of TVA and its metabolites are epidemiologically related to a reduced risk of insulin resistance and type 2 diabetes (T2D). However, direct causative evidence is lacking, and the mechanisms are poorly understood. The objective of this study was to evaluate whether TVA can alleviate insulin resistance in diet-induced obese mice when compared with oleic acid (OA, cis9-18:1, the major dietary cis 18:1 isomer) or trans10-18:1 (a major industrial trans fatty acid isomer). Forty-eight male C57BL/6J mice (7 weeks old) were fed either a low-fat diet (LFD,10% kcal total fat), a high-fat diet (HFD) enriched with OA (HFD-OA; 45% kcal total fat, 6% kcal from pure OA), an HFD enriched with TVA (HFD-TVA; 45% kcal total fat, 6% kcal from pure TVA), or an HFD enriched with trans-10 18:1 (HFD-T10; 45% kcal total fat, 6% kcal from pure trans-10 18:1) for 19 weeks. The metabolic phenotype was characterized using a glucose tolerance test (GTT) and insulin tolerance test (ITT). Insulin-sensitive tissues (muscle, liver, and adipose) were harvested and extracted for protein, which was analyzed for protein kinase B (Akt) and phosphorylated Akt (pAKT) by western blot using Vinculin as a loading control. The resulting band intensities were quantitated using the FluorChem 9900 program (Alpha Innotech). pAkt expression was normalized to Akt. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s test. Our GTT results suggested a greater (P < 0.05) glucose intolerance in both HFD-TVA and HFD-T10 groups compared with the LFD group. Whereas HFD-OA-fed mice maintained their glucose tolerance and insulin sensitivity despite greater body weight and adiposity. In agreement with GTT and ITT results, we found reduced (P < 0.05) Akt phosphorylation in the muscle of both HFD-TVA and HFD-T10 groups compared with LFD while there was no difference in phosphorylation level in the liver and adipose. In conclusion, this work demonstrates that contrary to our initial hypothesis, a large dose of TVA (6% of calorie intake) promotes glucose intolerance and insulin resistance in HFD-fed mice. Further studies using the typical intake of TVA in humans (0.5 to 1% of calorie intake) are required to better understand the effects of TVA on glucose homeostasis.

Development of biotechnologically transesterified three-component fat systems stable to oxidation

The object of the research is the period of induction of accelerated oxidation of biotechnologically transesterified fatty systems that do not contain trans isomers of fatty acids. The paper defines the rational ratio of fatty raw materials in mixtures for biotechnological transesterification. The results obtained make it possible to develop biotechnologically transesterified three-component fat systems (palm stearin, coconut and sunflower, or soybean, or corn, or sesame oil) to obtain substitutes for milk fat. The proposed calculation of melting points of transesterified fat systems of a wide range of ratios of raw components allows us to justify such rational ratios of components that allow obtaining finished products with a melting point of 33.0...33.5 °С. It is effective to use the products of the developed composition in view of the technological requirements of consumers for their oxidizing capacity. The data obtained in the work are explained by the fatty acid and antioxidant composition of low-melting components of fat systems in a different range of their ratios, which determines different technological properties, in particular, the melting point and stability to oxidation of finished products. A feature of the obtained results is the competitiveness of the obtained fat systems, which are characterized by the absence of atherogenic components and the presence of biologically valuable polyunsaturated fatty acids in the composition. The results of the research make it possible to minimize the cost of raw components while preserving the nutritional value and technological characteristics. An applied aspect of using the scientific result is the possibility of expanding the range of milk fat substitutes with high nutritional value

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 50m 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 30m polyethylene glycol-2-nitroterephthalate column. The FAs thus quantitated allowed the discovery of specific biomarkers for the origins of cheese varieties highly consumed in several countries. In addition, the simple and multivariate correlations we found between FAs in the cheese TAG matrix were alternative means for characterization and authentication purposes.

Enrichment and structural assignment of geometric isomers of unsaturated furan fatty acids.

Furan fatty acids (FuFAs) are valuable minor fatty acids, which are known for their excellent radical scavenging properties. Typically, the furan moiety is embedded in an otherwise saturated carboxyalkyl chain. Occasionally, these classic FuFAs are accompanied by low amounts of unsaturated furan fatty acids (uFuFAs), which additionally feature one double bond in conjugation with the furan moiety. A recent study produced evidence for the occurrence of two pairs of E-/Z-uFuFA isomers structurally related to saturated uFuFAs. Here, we present a strategy that allowed such trace compounds to be enrichedto a level suited for structure determination by NMR. Given the low amounts and the varied abundance ratio of the four uFuFA isomers, the isolation of individual compounds was not pursued. Instead, the entire isomer mixture was enriched to an amount and purity suitable for structure investigation with contemporary NMR methods. Specifically, lipid extracted from 150g latex, the richest known source of FuFAs, was subsequently fractionated by countercurrent chromatography (CCC), silver ion, and silica gel column chromatography. Analysis of the resulting mixture of four uFuFAs isomers (2.4mg in an abundance ratio of 56:23:11:9) by different NMR techniques including PSYCHE verified that the structures of the two most abundant isomers were E-9-(3-methyl-5-pentylfuran-2-yl)non-8-enoic acid and E-9-(3-methyl-5-pent-1-enylfuran-2-yl)nonanoic acid. Additionally, we introduced a computer-based method to generate an averaged chromatogram from freely selectable GC/MS runs of CCC fractions without the necessity of pooling aliquots. This method was found to besuitable to simplify subsequent enrichment steps.

Geometrical isomerization of arachidonic acid during lipid peroxidation interferes with ferroptosis.

Geometrical mono-trans isomers of arachidonic acid (mtAA) are endogenous products of free radical-induced cis-trans double bond isomerization occurring to natural fatty acids during cell metabolism, including lipid peroxidation (LPO). Very little is known about the functional roles of mtAA and in general on the effects of mono-trans isomers of polyunsaturated fatty acids (mtPUFA) in various types of programmed cell death, including ferroptosis. Using HT1080 and MEF cell cultures, supplemented with 20μM PUFA (i.e., AA, EPA or DHA) and their mtPUFA congeners, ferroptosis occurred in the presence of RSL3 (a direct inhibitor of glutathione peroxidase 4) only with the PUFA in their natural cis configuration, whereas mtPUFA showed an anti-ferroptotic effect. By performing the fatty acid-based membrane lipidome analyses, substantial differences emerged in the membrane fatty acid remodeling of the two different cell fates. In particular, during ferroptosis mtPUFA formation and their incorporation, together with the enrichment of SFA, occurred. This opens new perspectives in the role of the membrane composition for a ferroptotic outcome. While pre-treatment with AA promoted cell death for treatment with H2O2 and RSL3, mtAA did not. Cell death by AA supplementation was suppressed also in the presence of either ferroptosis inhibitors, such as the lipophilic antioxidant ferrostatin-1, or NADPH oxidase (NOX) inhibitors, including diphenyleneiodonium chloride and apocynin. Our results confirm a more complex scenario for ferroptosis than actually believed. While LPO processes are active, the importance of environmental lipid levels, balance among SFA, MUFA and PUFA in lipid pools and formation of mtPUFA influence the membrane phospholipid turnover, with crucial effects in the occurrence of cell death by ferroptosis.