Food Lipids Research Articles

Fatty acid profiles as natural tracers of provenance and lipid quality indicators in illegally sourced fish and bivalves

Determining where harvested or produced seafood comes from is a pressing issue worldwide, with growing consumers’ demand for traceable and sustainable seafood products. Identifying fine-scale traceability markers is particularly important in the context of small-scale fisheries, which are prone to illegal harvesting and mislabelling and associated food safety risks. Here we explored the power of fatty acid profiling as a fine-scale tracer of the geographical origin (<30 km apart) of the Peppery furrow shell bivalve (Scrobicularia plana) and the European seabass (Dicentrarchus labrax) collected in three locations within a large, urbanized estuary. Fatty acid profiling provided a high classification accuracy of both species to their collection sites (80%–100% for the seabass and the bivalve respectively). Fatty acid profiling also allowed the determination of food lipid quality indices. The EPA + DHA values and the atherogenic (Ai), thrombogenic (Ti) and the hypocholesterolemic/hypercholesterolemic (h/H) indexes were all within ranges of high lipid-quality seafood, albeit they varied significantly among collection sites (except h/H). Overall, results highlight the strength of fatty acid profiling as a natural marker to trace the geographic origin of small-scale fisheries products, which may be integrated into a broader regulatory monitoring framework.

An overview on recent advances in functional properties of dietary lipids, encapsulation strategies and applications

PurposeThe purpose of this study was to provide contemporary scientific knowledge on the functionality of edible lipids, sources, health benefits, and a special emphasis on different encapsulation strategies to enhance their dietary application and boost the market value.Design/methodology/approachNovel technologies overcoming these issues are in great demand. Given that, several novel encapsulation techniques have been established aiming at most of the aspects of functional lipids. In addition, these techniques have been designed to enhance the storage stability and controlled release of lipids in food systems.FindingsPlant and marine oils are one of the richest sources of functional lipids but are attached with limitations. Currently, alternative sources, such as different types of algae and microorganisms are gaining attention in terms of sustainable production systems. Advances in various encapsulation techniques have helped to overcome the dispersibility and stability problems of lipids encapsulation. Refinement in physicochemical interaction, colloidal dispersion and core-shell modules between wall and core matrix protect dietary lipids during processing have been implemented. Liposomes, micro/nanoemulsions and micro/nanocapsules are found most suitable for food application by improving the fatty acid profile, stability and sensorial properties.Originality/valueFunctional lipids offer numerous health benefits (i.e., simple health-promoting properties to complex disease preventive and curative effects). However, these functional lipids are associated with several disadvantages, such as region-specific availability, vulnerability to oxidation depending on the level of unsaturation, degradation/hydrolysis on processing, low bioavailability, confined storage stability, and others.

FABRICATION, OPTIMIZATION AND EX-VIVO CHARACTERIZATION OF FEBUXOSTAT LOADED NANOSTRUCTURED LIPID CARRIER BY 3 SQUARE FULL FACTORIAL DESIGN

Nano Structured Lipid Carriers (NLCs) are potential alternative of the tradition colloidal drug carrier. The main benefit is related to the well-known concept that lipids used in nanoparticle formulation promote drug oral absorption because they go through the same physiological mechanism as food lipid digestion. The objective of the present work is to use potential carrier NLCs for the oral delivery of poorly soluble drug Febuxostat (FEB). FEB-NLCs were formulated by High Speed Homogenization with Ultra sonication method using Capmul GMS 50 K as solid lipid and Transcutol HP as a liquid lipid. The 32 full factorial design utilized to study the effect of influence of solid lipid to liquid lipid ratio and concentration of surfactant, on the particle size and entrapment efficiency. Mean particle size and entrapment efficiency were found for all prepared formulation in the range of 196.66±2.08 nm to 368.33±2.51 nm and 74.80±0.52 % to 86.47±0.749 % respectively. Zeta potential was -15.2mv which is negative enough to give good stability. TEM study shows good spherical morphology of particle with diameter less than 200nm. In-vitro and Ex-Vivo study revel that NLCs gives biphasic release of the drug; first initial burst release and then sustained release up to 24 hour. The formulated NLCs dispersion was successfully converted in to the free flowing powder using trehalose as a cryoprotectant. In conclusion, FEB-NLCs potential carrier for the oral delivery and controlled release of drug which may reduce dosing frequency and improve patient compliance.

Impact of Cold Atmospheric Plasma (CAP) Treatments on the Oxidation of Pistachio Kernel Lipids.

Cold atmospheric plasma (CAP) is a non-thermal technology that could be applied for food decontamination from both biological (microorganisms) and chemical (pesticides, food allergens, mycotoxins) contaminants, thanks to the production of reactive species (RS). However, RS could also promote the onset and the progress of food lipid oxidation, which may limit the quality and acceptability of the final products. The aim of this work was to assess the oxidation degree of pistachio kernels after treatment in a surface dielectric barrier discharge (SDBD). Two different operative conditions for CAP generation were investigated, resulting in the production of high (800 ppm) or low (300 ppm) concentrations of ozone. Limited amounts of hydroperoxides (3.00–4.22 mEq O2/kg), thiobarbituric acid reactive substances (TBARS, 0.072–0.600 mg TEP/g oil), and phytosterol oxidation products (POPs, 14.43–17.20 μg/g) were observed in lipids of both control and plasma processed pistachios. Plasma treatments did not significantly affect the total fatty acid composition and the amounts of identified unsaponifiable matter constituents (4-desmethylsterols, 4,4-dimethylsterols, 4-methylsterols), except for an unexpected significant increase of γ-tocopherol content in extracted oils. These findings contribute to gaining further knowledge for the scale-up of CAP technology to industrial processing.

Exogenous fatty acids affect membrane properties and cold adaptation of Listeria monocytogenes

Listeria monocytogenes is a food-borne pathogen that can grow at very low temperatures close to the freezing point of food and other matrices. Maintaining cytoplasmic membrane fluidity by changing its lipid composition is indispensable for growth at low temperatures. Its dominant adaptation is to shorten the fatty acid chain length and, in some strains, increase in addition the menaquinone content. To date, incorporation of exogenous fatty acid was not reported for Listeria monocytogenes. In this study, the membrane fluidity grown under low-temperature conditions was affected by exogenous fatty acids incorporated into the membrane phospholipids of the bacterium. Listeria monocytogenes incorporated exogenous fatty acids due to their availability irrespective of their melting points. Incorporation was demonstrated by supplementation of the growth medium with polysorbate 60, polysorbate 80, and food lipid extracts, resulting in a corresponding modification of the membrane fatty acid profile. Incorporated exogenous fatty acids had a clear impact on the fitness of the Listeria monocytogenes strains, which was demonstrated by analyses of the membrane fluidity, resistance to freeze-thaw stress, and growth rates. The fatty acid content of the growth medium or the food matrix affects the membrane fluidity and thus proliferation and persistence of Listeria monocytogenes in food under low-temperature conditions.

Melting, Crystallization, and In Vitro Digestion Properties of Fats Containing Stearoyl-Rich Triacylglycerols.

Fats containing the stearoyl-rich triacylglycerols (TAGs) of 1,2-distearoyl-3-oleoylglycerol (SSO) and 1,3-dioleoyl-2-stearoylglycerol (OSO) were synthesized via the lipase-catalyzed acidolysis of tristearin (SSS)-rich fat and oleic acids, followed by solvent fractionation. Their physicochemical properties and in vitro digestibilities were compared. The SSS-, SSO-, and OSO-rich fats comprised 81.6%, 52.9%, and 33.1% stearic acid, respectively, whereas oleic acid comprised 2.9%, 37.5%, and 56.2%, respectively. The SSS-, SSO-, and OSO-rich fats contained the TAGs of SaSaSa (100.00%), SaSaMo (86.98%), and MoSaMo (67.12%), respectively, and the major TAGs were SSS, SSO, and OSO, respectively. Melting and crystallization temperatures were higher and fat crystals were larger and densely packed in the descending order of SSS-, SSO and OSO-rich fats. Both in vitro multi-step digestion and pH-stat digestion were more rapid for OSO- than SSO-rich fat. Oleic acid was digested faster than stearic acid during the initial digestion, then the rate decreased, whereas that of stearic acid increased over prolonged digestion. Fats that were richer in stearoyl at the sn-1,3 position of TAG melted and crystallized at higher temperatures, had a densely packed microstructure of large fat crystals and were poorly digested. Stearic acid imparts the essential physical attributes of melting and crystallization in solid fats, and the low digestible stearoyl-rich fat would be a viable substitute for trans fatty acids in food lipid industry.

Factors impacting the antioxidant/prooxidant activity of tea polyphenols on lipids and proteins in oil-in-water emulsions

Tea polyphenols (TP) may inhibit or promote the oxidation of proteins and lipids in foods, depending on system conditions. In this study, we examined the effects of TP concentration (0, 100, and 400 mg/L), solution pH (3 and 7), and the addition of ethylenediaminetetraacetic acid (0 or 20 μmol/L EDTA) on the antioxidant/prooxidant activities of TP in walnut oil-in-water (O/W) emulsions under accelerated storage conditions (50 °C for 0, 48, 96 h). At pH 3, a lower concentration of TP (100 mg/L) exhibited stronger antioxidant activity for lipids and proteins than the higher concentration (400 mg/L). At pH 7, the lower concentration of polyphenols was still more effective, while the higher concentration resulted in prooxidant activity toward the proteins. In the absence of TP, the incorporation of EDTA into the emulsions (pH 7) inhibited lipid and protein oxidation, which was attributed to its ability to chelate and inactivate the prooxidant transition metals. Interestingly, the antioxidant activity of EDTA decreased in the presence of TP. Therefore, these results suggested that TP could be used to retard protein and lipid oxidation in emulsion-based foods, but their levels should be optimized due to their complex prooxidant and antioxidant mechanisms, depending on system composition and environmental conditions.

Antihyperlipidemic and Antiobesity Potential of Aquilaria agallocha and Borago officinalis in Fixed-Dose Combination; A Contingent Probe with Atorvastatin and Orlistat

Aims: Antihyperlipidemic and antiobesity potential of a fixed dose combination of Aquilaria agallocha &amp; Borago officinalis along with its comparative evaluation with Atorvastatin &amp; Orlistat. Background: Hyperlipidemia and obesity are common and challenging health problems throughout the world. These are the conditions in which increased lipids level in blood are the risk factors for atherosclerosis, coronary artery disease, and cerebral vascular diseases. In the present study, the fixed-dose combination of absolute ethanolic extract of Aquilaria agallocha and aqueous extract of Borago officinalis was examined for its antihyperlipidemic effect and antiobesity activity in the Sprague Dawley rats. Objective: A suitable &amp; established experimental model of hyperlipidemia and obesity based on literature survey has been selected. Comparative evaluation of fixed dose combination with selected standard drug against the established model. Compilation of results and statistical analysis. Methods: Drugs and Chemicals: Atorvastatin solution, Orlistat solution, Formalin solution Animals: sprague dawley rats of 150-200 g of either sex were used for the study. Animals were habituated to laboratory conditions for 48 hours prior to experimental protocol to minimize if any of nonspecific stress. All the studies conducted were approve by the Institutional Animal Ethical Committee (IAEC) of Faculty of Pharmacy, Integral University Lucknow (Reg. no. 1213/PO/Re/S/08/CPCSEA, 5th June 2008) having approval no. IU/IAEC/18/32. High fat diet induced Dyslipidemia and obesity: Baseline characteristics of obesity and hyperlipedimia induced by high fat diet in Sprague dawley rats were maintained on normal pellet diet (NPD) for one week before the commencement of experiment. After one week rats were randomly assigned into normal and obese group and fed with NPD and High fat diet and libitum respectively for one week.The food intake, body weight gain ,and lipid profile were carried out on day 8 of dietary manipulation to assess the baseline characteristics of obesity and hyperlipidemia induced by high fat diet in Sprague dawley rats. Results: The result of the study shows that the ethanolic extract of the FDC of aquilaria agallocha &amp; borago officinalis has significant anti-hyperlipidemic and anti-obesity activity against High- fat diet-induced hyperlipidemia and obesity compared to atorvastatin (10 mg/kg) and orlistat (pure drug 10mg/kg). Conclusion: The present study shows that pretreatment with ethanolic extract of FDC of Aquilaria agallocha &amp; Borago officinalis significantly prevented from hyperlipidemia and obesity and decreased the levels of diagnostic marker enzymes significantly. At low dose (Borago officinalis 100 mg/kg + Aquilaria agallocha 250 mg/kg b.w.) ) ethanolic extract of FDC of Aquilaria agallocha &amp; Borago officinalis showed moderate protection against Hyperlipidemia and Obesity. At high dose (Borago officinalis 200 mg/kg + Aquilaria agallocha 500 mg/kg b.w.) ethanolic extract of FDC of Aquilaria agallocha &amp; Borago officinalis showed marked protection against High fat diet induced hyperlipidemia and obesity as well as by biochemical estimations of Lipid profile compare to the standard Atorvastatin(10mg/kg) and Orlistat(10mg/kg). Thus it concludes that ethanolic extract of FDC of Aquilaria agallocha &amp; Borago officinalis possesses potent against high fat diet induced hyperlipidemia and obesity.

Stability of Bioactive Compounds in Olive-Pomace Oil at Frying Temperature and Incorporation into Fried Foods.

The stability of minor bioactive compounds in olive-pomace oils (OPOs) was evaluated at frying temperature under the conditions of a thermoxidation test. Bioactive compounds analyzed included squalene, tocopherols, sterols, triterpenic acids and alcohols, and aliphatic alcohols. In order to determine the amount of OPO bioactive compounds incorporated into foods after frying, three different kinds of frozen products were selected, i.e., pre-fried potatoes (French fries), pre-fried battered chicken nuggets, and chicken croquettes (breaded patties), and were used in discontinuous frying experiments. Results obtained in both the thermoxidation and frying studies showed high stability of triterpenic alcohols (erythrodiol and uvaol), oleanolic acid, and aliphatic alcohols, naturally present in OPOs. In all fried foods, the content of lipids increased after frying, as expected, although the extent of absorption of OPOs into fried foods and the exchange with food lipids depended on the food characteristics. Overall, frying with OPOs improved the nutritional properties of all products tested by increasing the level of oleic acid and by the incorporation of squalene, triterpenic acids and alcohols, and aliphatic alcohols, in significant quantities.

Phospholipids as natural emulsifiers in food and beverages

Phospholipids play significant roles in numerous biological processes. They also have many applications in food, cosmetics, and pharmaceuticals. This article reviews the molecular structure, properties, and uses of these important lipids in food, beverages, and food supplements.

Adverse effects of linoleic acid: Influence of lipid oxidation on lymphatic transport of citrus flavonoid and enterocyte morphology

Lipids usually contain a large ratio of polyunsaturated fatty acids (PUFAs), which are highly susceptible to oxidation. Presence of oxidized lipids in foods may affect the bioavailability of lipophilic bioactive components after ingestion. In this study, the effect of oxidized and unoxidized linoleic acid (LA) on the transport of a highly lipophilic bioactive citrus flavonoid (5-hydroxy – 6, 7, 8, 4′ tetramethoxylflavone or 5-DMT) was determined using a Caco-2 cell model. Results demonstrated that compared to free 5-DMT, unoxidized LA improved the trans-enterocyte absorption of 5-DMT by stimulating the production of lipid droplets and chylomicrons. Although the amount of 5-DMT transported across the enterocyte doubled by oxidized LA compared to free 5-DMT, it significantly induced reactive oxygen species (ROS), affected the function of tight junction and caused damages to the morphology of enterocyte monolayer. This study re-emphasized the importance of preventing lipid oxidation in foods.

Determination of Oxidized Lipids in Commonly Consumed Foods and a Preliminary Analysis of Their Binding Affinity to PPARγ.

Foods rich in poly unsaturated fatty acids (PUFA) are vulnerable to oxidation. While it is well established that endogenously derived oxidized lipids are ligands of the transcription factor PPARγ, the binding ability of diet-derived oxidized lipids is unknown. Our two-fold objective was to determine the oxidized lipid content and PPARγ binding ability of commonly consumed foods. Extracted food lipids were assayed for the peroxide value, conjugated dienes, and aldehydes, and PPARγ binding was assessed by an in vitro PPARγ ligand screening assay. Oxidized lipids were present in all foods tested at the time of purchase, and oxidation did not increase during storage. The peroxide values for walnuts, sunflower seeds, and flax meal were significantly lower at the end of three months as compared to the day of purchase (peroxide value: 1.26 ± 0.13 vs. 2.32 ± 0.4; 1.65 ± 0.23 vs. 2.08 ± 0.09; 3.07 ± 0.22 vs. 9.94 ± 0.75 mEq/kg fat, p ≤ 0.05, respectively). Lipids extracted from French fries had the highest binding affinity (50.87 ± 11.76%) to PPARγ compared to other foods. Our work demonstrates that oxidized lipids are present in commonly consumed foods when purchased, and for the first time demonstrates that some contain ligands of PPARγ.

Formation kinetics of radiolytic lipid products in model food–lipid systems with gamma irradiation

AbstractIrradiation processes can change the lipid composition of foods. The major lipid radiolysis products are known to be 2‐alkylcyclobutanones and hydrocarbons, the formation kinetics of which is determined by the chemical nature of the inherent lipids. This information can be used to evaluate the irradiation history of lipid‐rich foods. A solid‐phase microextraction (SPME)‐assisted gas chromatography–mass spectrometry (GC–MS) technique was used to study the formation of volatile hydrocarbons and 2‐dodecylcyclobutanone (2‐DCB), a cyclobutanone formed from the esters of palmitic acid, in irradiated (0–50 kGy) tripalmitin and chicken fat. Thirty‐three volatile compounds (hydrocarbons, aldehydes, ketones) increased with irradiation dose to varying extents. Six major lipid radiolysis products were selected to analyze their formation kinetics: tridecane, 1‐tetradecene, tetradecane, 1‐pentadecene, pentadecane, and 2‐DCB. The concentration of the selected compounds increased linearly with irradiation dose following zeroth‐order kinetics, except for tridecane and tetradecane in tripalmitin, formation of which followed first‐order kinetics. The formation rate of hydrocarbons was higher in tripalmitin than in chicken fat (5× higher for pentadecane), while 2‐DCB formed faster (3.5×) in chicken fat than in tripalmitin. This difference was related to the diversity in the natural fatty acid composition of chicken fat as compared to the homogeneous structure of tripalmitin. The results of this study indicate that the concentrations of palmitic acid radiolysis products linearly increase with irradiation dose in general to offer potential to back‐trace irradiation dose in lipid‐rich foods.

Oleogel-based emulsions: Concepts, structuring agents, and applications in food.

This review discusses the application of oleogel technology in emulsified systems. In these systems of mimetic fats, water-in-oil or oil-in-water emulsions can be obtained, but, here, we cover emulsions with an oil continuous phase in detail. Depending on the percentage of water added to the oleogels, systems with different textures and rheological properties can be developed. These properties are affected by the characteristics and concentration of the added components and emulsion preparation methods. In addition, some gelators exhibit interfacial properties, resulting in more stable emulsions than those of conventional emulsions. Oleogel-based emulsion are differentiated by continuous and dispersed phases and the structuring/emulsification components. Crucially, these emulsions could be applied by the food industry for preparing, for example, meat products and margarines, as well as by the cosmetics industry. We present the different processes of emulsion elaboration, the main gelators used, the influence of the water content on the structuring of water-in-oleogel emulsions, and the structuring mechanisms (Pickering, network, and combined Pickering and network stabilization). Finally, we highlight the applications of these systems as alternatives for reducing processed food lipid content and saturated fat levels.

Does lysine drive the conversion of fatty acid hydroperoxides to aldehydes and alkyl-furans?

During the oxidation of lipids in food or in vivo, fatty acids are initially converted to hydroperoxides, which undergo decomposition to various secondary decomposition products, including aldehydes and alkyl-furans. Aldehydes and alkyl-furans reduce the sensory quality of food by contributing to rancidity, and aldehydes reduce nutritional value by reacting with some essential nutrients such as lysine and thiamine. In vivo, reactions of aldehyde with proteins and DNA contribute to the pathogenesis of physiological disorders. Conversion of fatty acid hydroperoxides to aldehydes is generally believed to involve free radical reactions. However, it was recently hypothesized that lysine can catalyze the non-radical conversion of hydroperoxides to aldehydes. Thus the aim of the present study was to determine such lysine-catalysed conversion of linoleic acid hydroperoxides to aldehydic products. Linoleic acid hydroperoxides were prepared by the photosensitized oxidation of linoleic acid. The mixture of hydroperoxides was reacted with lysine, in the presence of a radical scavenger, and the organic fraction analysed by gas chromatography-mass spectrometry (GC-MS). Hexanal was detected as a major aldehydic product. The alkylfuran, 2-pentylfuran was also surprisingly detected under these conditions, and a pathway for its lysine-catalysed formation via the highly cytotoxic aldehyde, 4-hydroxy-2-nonenal proposed. The results of this study imply that, in the prevention of lipid oxidation-associated food deterioration and development of physiological disorders, more attention should be paid to pathways not involving free radical reactions, and which cannot be prevented by radical scavenging antioxidants.

Biomarkers of lipid metabolism in patients with juvenile idiopathic arthritis: relationship with disease subtype and inflammatory activity

BackgroundTo describe the biomarkers of lipid metabolism in children and adolescents with polyarticular and systemic JIA and to relate them to diseases subtypes, diseases activity markers, and nutritional status.MethodsA cross-sectional study including 62 JIA patients was performed. The following variables were evaluated: disease activity and medications used, body mass index, height for age (z-score), skin folds (bicipital, tricipital, subscapular and suprailiac), food intake based on three 24-h food recalls, lipid profile (total cholesterol (CT), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG) and non-HDL (N-HDLc), glycemia and insulin, erythrocyte sedimentation rate (ESR), ultrasensitive C-reactive protein (us-CRP) and apolipoproteins A-I and B (Apo A-I and Apo B).ResultsDyslipidemia was observed in 83.3% of the patients. Based on classical lipid profile, low HDL-c levels was the most frequently alteration observed. Inadequate levels of LDL-c, Apo B and NHDL-c were significantly more frequent in the systemic JIA subtype when compared to the polyarticular subtype (p = 0.017, 0.001 and 0.042 respectively). Patients on biological therapy had a better adequacy of Apo A-I concentrations. The ESR showed a negative correlation with Apo A-I level (r = − 0.25, p = 0.047).ConclusionWe concluded that dyslipidemia is common in patients with JIA, especially in systemic subtype. The systemic subtype and an elevated ESR were associated with lower concentrations of Apo A-I, suggesting the participation of the inflammatory process.

Oxidation in Low Moisture Foods as a Function of Surface Lipids and Fat Content.

Lipid oxidation is a major limitation to the shelf-life of low moisture foods and can lead to food waste. Little is known of whether the surface lipids in low moisture foods are more susceptible to oxidation since they are exposed to the environment. Therefore, the purpose of this research is to compare the rate of oxidation in surface and total lipids. Lipids in crackers were found to be in a heterogeneous matrix with proteins and starch, as determined by confocal microscopy. However, unlike spray-dried powders, both surface and interior lipids oxidized at similar rates, suggesting that the cracker matrix was not able to protect lipids from oxidation. Increasing the fat content of the crackers increased oxidation rates, which could be due to differences in the lipid structure or higher water activities in the high-fat crackers.

Antioxidant activities of lipophilic (−)-epigallocatechin gallate derivatives in vitro and in lipid-based food systems

The low lipophilicity of (−)-epigallocatechin gallate (EGCG) significantly limits its applications in lipophilic systems. Herein, EGCG was acylated with vinyl esters of different carbon chain lengths under the action of the lipase Novozym 435. Five EGCG derivatives (C2-EGCG, C4-EGCG, C6-EGCG, C8-EGCG, and C12-EGCG) with different lipophilicities were obtained, and their antioxidant activities were evaluated. Due to the loss of the phenolic hydroxyl group of EGCG, the capacities of these derivatives to scavenge the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS+•), 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•), and hydroxyl radical (•OH) were lower than those of EGCG. In a homogeneous oil system, the antioxidant capacities of the EGCG derivatives were higher than that of EGCG. Upon increasing the lipophilicities of the derivatives, the antioxidant activities initially increased and later decreased, thus demonstrating the “cut-off effect.” Among the various derivatives, C8-EGCG possessed the highest antioxidant activity. In the oil-in-water emulsions, optimum antioxidant activity was observed for short carbon chain length (C2-EGCG). This study therefore provides useful information regarding the design of EGCG applications in food lipid systems.

Pseudotargeted Lipidomics Strategy Enabling Comprehensive Profiling and Precise Lipid Structural Elucidation of Polyunsaturated Lipid-Rich Echium Oil.

Echium oil has great nutritional value as a result of its high content of α-linolenic acid (ALA, 18:3ω-3) and stearidonic acid (SDA, 18:4ω-3). However, the comprehensive lipid profiling and exact structural characterization of bioactive polyunsaturated lipids in echium oil have not yet been obtained. In this study, we developed a novel pseudotargeted lipidomics strategy for comprehensive profiling and lipid structural elucidation of polyunsaturated lipid-rich echium oil. Our approach integrated untargeted lipidomics analysis with a targeted lipidomics strategy based on Paternò-Büchi (PB)-tandem mass spectrometry (MS/MS) using 2-acetylpyridine (2-AP) as the reaction reagent, allowing for high-coverage lipid profiling and simultaneous determination of C═C locations in triacylglycerols (TGs), diacylglycerols (DGs), free fatty acids (FFAs), and sterol esters (SEs) in echium oil. A total of 209 lipid species were profiled, among which 162 unsaturated lipids were identified with C═C location assignment and 42 groups of ω-3 and ω-6 C═C location isomers were discovered. In addition, relative isomer ratios of certain groups of lipid C═C location isomers were revealed. This pseudotargeted lipidomics strategy described in this study is expected to provide new insight into structural characterization of distinctive bioactive lipids in food.

The mTORC1 complex in pre-osteoblasts regulates whole-body energy metabolism independently of osteocalcin

Overnutrition causes hyperactivation of mTORC1-dependent negative feedback loops leading to the downregulation of insulin signaling and development of insulin resistance. In osteoblasts (OBs), insulin signaling plays a crucial role in the control of systemic glucose homeostasis. We utilized mice with conditional deletion of Rptor to investigate how the loss of mTORC1 function in OB affects glucose metabolism under normal and overnutrition dietary states. Compared to the controls, chow-fed Rptorob−/− mice had substantially less fat mass and exhibited adipocyte hyperplasia. Remarkably, upon feeding with high-fat diet, mice with pre- and post-natal deletion of Rptor in OBs were protected from diet-induced obesity and exhibited improved glucose metabolism with lower fasting glucose and insulin levels, increased glucose tolerance and insulin sensitivity. This leanness and resistance to weight gain was not attributable to changes in food intake, physical activity or lipid absorption but instead was due to increased energy expenditure and greater whole-body substrate flexibility. RNA-seq revealed an increase in glycolysis and skeletal insulin signaling pathways, which correlated with the potentiation of insulin signaling and increased insulin-dependent glucose uptake in Rptor-knockout osteoblasts. Collectively, these findings point to a critical role for the mTORC1 complex in the skeletal regulation of whole-body glucose metabolism and the skeletal development of insulin resistance.