Longitudinal Evolution of the Concentration of Gangliosides GM3 and GD3 in Human Milk

It has been reported that dietary gangliosides may have an important role in preventing infections and in brain development during early infancy. However, data related to the evolution of their concentration over the different stages of lactation are scarce. Liquid chromatography coupled with electrospray ionization high resolution mass spectrometer (LC/ESI‐HR‐MS) has been optimized to quantify the two major ganglioside classes, i.e., aNeu5Ac(2‐8)aNeu5Ac(2‐3)bDGalp(1‐4)bDGlcp(1‐1)Cer (GD3) and aNeu5Ac(2‐3)bDGalp(1‐4)bDGlcp(1‐1)Cer (GM3) in human milk. Gangliosides were extracted using chloroform and methanol, further purified by solid‐phase extraction and separated by reversed‐phase liquid chromatography. Repeatability, intermediate reproducibility, and recovery values were assessed to validate the method. In human milk, GD3 and GM3 could be quantified at the level of 0.1 and 0.2 μg/mL, respectively, with relative standard deviation of repeatability [CV(r)] and intermediate reproducibility [CV(iR)] values ranging from 1.9 to 15.0 % and 1.9 to 22.5 %, respectively. The described method was used to quantify GD3 and GM3 in human milk samples collected from 450 volunteers between 0 and 11 days and at 30, 60 and 120 days postpartum, providing for the first time the concentration of these minor lipids in a large cohort. The content of total gangliosides ranged from 8.1 and 10.7 μg/mL and the mean intake of gangliosides in infants 30, 60 and 120 days postpartum could be estimated at about 5.5, 7.0 and 8.6 mg of total gangliosides per day, respectively, when infants were exclusively breastfed.     

Lipid Classes and Subclasses of Cold-Pressed and Solvent-Extracted Oils from Commercial Indian Niger (Guizotia abyssinica (L.f.) Cass.) Seed

Lipid classes and subclasses of cold-pressed and solvent-extracted (hexane and ethanol) oils from commercially available niger (Guizotia abyssinica (L.f.) Cass.) seeds were investigated. The oil yield of niger seeds obtained by cold pressing was 28.3 g/100 g while by hexane and ethanol extractions was 38.3 and 29.7 g/100 g respectively. The lipid classification of the extracted niger seed oils showed neutral lipids (65.9–95.5 %), glycolipids (2.7–24.6 %) and phospholipids (1.8–9.5 %). The acylglycerol composition of neutral lipids of extracted niger seed oils showed triacylglycerols (76.9–91.6 %), diacylglycerols (3.9–7.3 %) and monoacylglycerols (0.6–2.5 %). The fatty acid composition of tri-, di-, and monoacylglycerols of extracted niger seed oils showed linoleic acid (66.7–71.6 %) as the major fatty acid. The triacylglycerol composition of neutral lipids of extracted niger seed oils showed trilinolein (39.2–40.3 %) as the major triacylglycerol. The extracted niger seed oils contained 1289.9–6215.8 ppm of total phytosterols with β-sitosterol (41.9–43.7 %) as the major phytosterol. Acylated steryl glucoside (39.5–52.2 %) was the major glycolipid in extracted niger seed oils. Phosphatidylcholine (49.6 and 47.9 %) was the major phospholipid in cold-pressed and hexane-extracted niger seed oils and phosphatidylethanolamine (57.1 %) was the major phospholipid in ethanol-extracted niger seed oil. This is probably the first report on the variations in lipid classes and subclasses of Indian niger seed oil as affected by different modes of oil extraction.     

Analysis of fatty acid profile in plasma phospholipids by solid‐phase extraction in combination with GC

Phospholipids are recognised as an important source and transport form for metabolically active fatty acids. Therefore, detailed analysis of fatty acid profiles in plasma phospholipids as marker for dietary habits or interventions gains more and more importance. Appropriate analytical methods described so far are either expensive or susceptible to handling errors. We developed a method to separate plasma phospholipids by acetone fractionation combined with SPE in order to analyse the fatty acid compositions in phospholipid fractions of human plasma by GC analysis. The method has been validated in order to be applied to the routinely performed analysis of the samples of patients who will be participating in a dietary supplement study. The method presented here was successfully validated and is stable, efficient and reproducible. It can be used in a routine fashion to deliver the fatty acid profile [palmitic acid (16:0), heptadecanoic acid (17:0), stearic acid (18:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6), linolenic acid (18:3n‐3), arachidonic acid (20:4n‐6), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3)] in plasma phospholipid samples. Using a sample volume of 500 µL, recovery of plasma phospholipids is 92 ± 11%; LOQ is 2.2 µg fatty acid/mL. A set of samples from cancer patients and healthy individuals was analysed and confirmed the applicability of the described method.     

Vergleich zur Identität von Phospholipiden aus Humanseren und daraus hergestellten HDL-Fraktionen

A Comparison of Phospholipids in Human Sera with Phospholipids in HDL-Fractions The phospholipid composition of human sera and HDL-fractions was analyzed and characterized. The phospholipids were extracted with Extrelut (Merck) according to the manufacturer's recommendation. The recovery of phospholipids (expressed as P_i before and after passage through the elution-column) was rather poor for sera (25%) and distinctly better for HDL-fractions (46%). Phosphatidylcholine is the main phospholipid in human sera and in a similar manner in the HDL-fraction. The fatty acid distribution of phosphatidylcholine in both fractions was assessed and the fatty acids in sn2-position were evaluated after hydrolysis with phospholipase A₂. The fatty acid profile for native lysophosphatidylcholine, extracted from sera, was compared to the fatty acid distribution of lysolecithin formed from lecithin of sera after hydrolysis with phospholipase A₂. Both lysolecithins differed distinctly in their fatty acid distribution. Phosphatidylcholine from sera was identical with phosphatidylcholine from the HDL-fractions concerning the fatty acid distribution and their positional isomerism. The small recovery of phospholipids after passage through an Extrelut-column is due to the strong protein-phospholipid interaction in sera and HDL-fractions.     

Fatty Acid Profiles of Commercially Available Finfish Fillets in the United States

Fillets of 76 finfish species (293 composites of three fish) were obtained from commercial seafood vendors in six regions of the United States (i.e., Great Lakes, Mid-Atlantic, New England, Northwest, Southeast, and Southwest). Full fatty acid profiles were determined for each species and are presented here. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been associated with many health benefits. Thus, fillets of each species were compared for total EPA plus DHA content, which ranged from 17 mg/100 g (pangasius/swai) to 2430 mg/100 g (Chilean sea bass). Of the top ten most popularly consumed seafoods in the US, finfish, including salmon species (717–1533 mg/100 g), Alaskan pollock (236 mg/100 g), tilapia (76 mg/100 g), channel catfish (44 mg/100 g), Atlantic cod (253 mg/100 g), and pangasius/swai (17 mg/100 g), exhibited a wide concentration range of EPA plus DHA. Large variances were found within many of the farmed species analyzed, which likely stems from dietary differences in the farm-fed diet. The results of this study provide current information on a broad range of species and will help nutritionists and the public make informed decisions regarding seafood consumption.     

Säulenchromatographische Abtrennung von Phospholipiden aus Gesamtlipidextrakten

Column Chromatographic Separation of Phospholipids from Total Lipid Extracts The separation of phospholipids out of total lipid extracts is described by using a column chromatographic method. Up to 800 mg total lipids in a mixture of chloroform and methanol (19 : 1, v/v) may be applied to dry-column-chromatography using 5 g silica gel as a matrix. Neutral lipids and free fatty acids are elutet by propanol-2. Following extraction of phospholipids is achieved by methanol, containing 0.5 ml/100 ml ammonia solution (25%). In the course of the preparation no lyso-phospholipids are formed and the composition of the phospholipidfraction is not altered. The recovery of applied phospholipids amounts 98-99.5%.     

Phospholipid composition of guinea pig lung lavage

Phospholipids from guinea pig lung lavage were analyzed. The total lavage phospholipid content was 2.65+0.67 mg, per gram of lung, which accounted for 85% of the total lipids in lung wash. Phosphatidylcholine (PC) accounted for over 60% of the total phospholipids. The other phospholipids factions, in order of pedominance, were phosphatidylinositol (PI), phosphatidylserine (PS), sphingomyelin (SPH), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and lysophosphatidyl-choline (LPC). Disaturated phosphatidylcholine (DSPC) comprised 80% of the total PC, and it contained ostly palmitic acid. The DSPC content of the lung lavage fluid per square meter of alveolar surface area was 5.76±0.42 mg.     

Phospholipid composition of cultured human endothelial cells

Detailed analyses of the phospholipid compositions of cultured human endothelial cells are reported here. No significant differences were found between the phospholipid compositions of cells from human artery, saphenous and umbilical vein. However, due to the small sample sizes, relatively large standard deviations for some of the phospholipid classes were observed. A representative composition of endothelial cells is: phosphatidylcholine 36.6%, choline plasmalogen 3.7%, phosphatidylethanolamine 10.2%, ethanolamine plasmalogen 7.6%, sphingomyelin 10.8%, phosphatidylserine 7.1%, lysophosphatidylcholine 7.5%, phosphatidylinositol 3.1%, lysophosphatidylethanolamine 3.6%, phosphatidylinositol 4,5-bisphosphate 1.8%, phosphatidic acid 1.9%, phosphatidylinositol 4-phosphate 1.5%, and cardiolipin 1.9%. The cells possess high choline plasmalogen and lysophosphatidylethanolamine contents. The other phospholipids are within the normal biological ranges expected. Phospholipids were separated by high-performance liquid chromatography and quantified by lipid phosphorus assay.     

Rosiglitazone,a PPAR-γ Agonist,Fails to Attenuate CLA-Induced Milk Fat Depression and Hepatic Lipid Accumulation in Lactating Mice

Our objective was to investigate the combination of rosiglitazone (ROSI) and conjugated linoleic acid (CLA) on mammary and hepatic lipogenesis in lactating C57Bl/6 J mice. Twenty-four lactating mice were randomly assigned to one of four treatments applied from postpartum day 6 to day 10. Treatments included: (1) control diet, (2) control plus 1.5 % dietary CLA (CLA) substituted for soybean oil, (3) control plus daily intra-peritoneal (IP) rosiglitazone injections (10 mg/kg body weight) (ROSI), and (4) CLA plus ROSI (CLA-ROSI). Dam food intake and milk fat concentration were depressed with CLA. However, no effects were observed with ROSI. The CLA-induced milk fat depression was due to reduced expression for mammary lipogenic genes involved in de-novo fatty acid (FA) synthesis, FA uptake and desaturation, and triacyglycerol synthesis. Liver weight (g/100 g body weight) was increased by CLA due to an increase in lipid accumulation triggering a compensatory reduction in mRNA abundance of hepatic lipogenic enzymes, including acetyl-CoA carboxylase I and stearoyl-CoA desaturase I. On the contrary, no effects were observed with ROSI on hepatic and mammary lipogenic gene and enzyme expression. Overall, feeding CLA to lactating mice induced milk fat depression and increased hepatic lipid accumulation, probably due to the presence of trans-10, cis-12 CLA isomer, while ROSI failed to significantly attenuate both hepatic steatosis and reduction in milk fat content.     

Triacylglycerol and Glycerophospholipid Identification and Accumulation During Ripening of Pistacia lentiscus L. (Lentisc) Fruit

Triacylglycerol (TAG) and phospholipid (PL) compositions of vegetable oils are considered a marker of quality and are often used in industry to control the purity of the oils and to detect adulteration. In this study, the TAG and PL composition of developing fruit of Pistacia lentiscus were investigated for the first time. The total TAG content was found to increase rapidly during fruit ripening from 105 to 966 mg/100 g of oil respectively between the 35th and the 175th day after fructification (DAF). During this period, 16 different molecular species of TAG were identified and quantified. POO was the major TAG from the second stage of maturation. Only four classes of PL were identified in the P. lentiscus oil: the phosphatidic acid (PA), the phosphatidylethanolamine (PE), the phosphatidylglycerol (PG) and the phosphatidylinositol (PI). The mass spectra obtained showed the presence of nine molecular species of PA, five species of PE and seven molecular species for each PG and PI classes. The total phospholipid content decreased rapidly during fruit ripening, from 45.5 % at the 15th DAF to 6.88 % at the 175th DAF.     

Lipid composition of commercially canned single-strength orange juice

The lipid composition of commercially canned single-strength orange juice ranged from 84–101 mg/100 ml juice (overall mean 95 ± 6). Phospholipid phosphorus, expressed as mg/100 ml juice, showed a range of from 1.56–1.95, while phospholipid phosphorus/lipid values (as µg-P/mg lipid) were within a very narrow range, 18.9 ± 1.1. The percentage distribution of lipid classes in these juices was 24–35% neutral lipids, 18–23% resin acids and glycolipids, and 43–53% phospholipids and other polar lipids. Five fatty acids, i.e. C₁₆, C_16:1, C_18:1, C_18:2, and C_18:3, accounted for over 93% of all fatty acids. The relative percentages of C_18:2 and C_18:3 differed between seasonal juices. The lipid composition does not warrant inclusion in nutritional labeling; however, lipid levels may be useful in detecting adulteration.     

Determination of phospholipids in vegetable oil by fourier transform infrared spectroscopy

A method was developed to determine the total phospholipid content in vegetable oil by Fourier transform infrared spectroscopy (FTIR). Calibration curves of I-α-phosphatidylcholine (PC), I-α-phosphatidylethanolamine (PE), and I-α-phosphatidylinositol (PI) in hexane were generated at different concentrations. The optimal phospholipid absorption bands between 1200–970 cm⁻¹ were identified and used for quantitative determination. High R ²≥0.968 were observed between band areas and phospholipid standard concentrations. Phospholipids from crude soybean oil were obtained by water degumming, and purification was performed on a silicic acid column. The phospholipid contents of purified phospholipid extract, degummed and crude soybean oil determined from calibration equations were >90, 0.0113, and 1.77%, respectively. High correlations of determination (R ²≥0.933) were observed between the FTIR method and thin-layer chromatography-imaging densitometry method for the determination of phospholipid content. FTIR was found to be a useful analytical tool for simple and rapid quantitative determination of phospholipids in vegetable oil.     

Physicochemical Properties and Minor Lipid Components of Soybean Germ

This study aimed to determine and to compare the main phytochemicals from soybean and soybean germ of different Chinese varieties. The results indicate that the soybean germ contains low protein (38.19 %), lipids (10.98 %), and crude fiber (7.47 %) compared with soybean. Specific gravity, refractive index, and saponification values of soybean germ oil were comparable to those of soybean oil. However, unsaponifiable matter of the germ oil was significantly higher (6.982 %) than soybean oil (1.072 %). The tocopherol contents in soybean germ oil ranged as follows: γ-tocopherol, 176.39 mg/100 g oil; δ-tocopherol, 57.29 mg/100 g oil; α-tocopherol, 50.67 mg/100 g oil; and β-tocopherol, 8.15 mg/100 g oil. The main sterols in soy germ oil were β-sitosterol (1,681.90 mg/100 g oil), crevesterol (358.02 mg/100 g oil), stigmasterol (189.62 mg/100 g oil), and brassicasterol (3.70 mg/100 g oil). Furthermore, soybean germ oil seemed to be an important source of triglyceride, fatty acids, and particularly the fatty acids in the sn-2 position of triacylglycerol. The important nutritional value of all these phytochemicals makes soybean germ and particularly germ oil sources of functional molecules and additives for the food industry.     

Characteristics of Oil and Skim in Enzyme-Assisted Aqueous Extraction of Soybeans

The economic viability of enzyme-assisted aqueous extraction processing (EAEP) of soybeans depends on properties and potential applications of all fractions (skim and insolubles as well as oil). EAEP oil contained lower free fatty acid, phosphorus, and tocopherol contents, similar unsaponifiable matter levels, and higher degrees of oxidation (peroxide and p-anisidine values) than hexane-extracted oil. The phospholipid profile of EAEP fractions was mainly composed of phosphatidic acid, followed by phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine. Most of phospholipids were present in the skim, except for phosphatidic acid, which was the major phospholipid in the cream fraction. Skim and cream contained 55 and 3 % of the soluble carbohydrates in the original extruded flakes, respectively. Soluble carbohydrates of the skim were mainly composed of stachyose (5.8 ± 0.8 mg/mL) and sucrose (9.9 ± 0.8 mg/mL), which were hydrolyzed into glucose, galactose, and fructose after addition of α-galactosidase. Skim and cream peptides contained <20 kDa MW molecules. About 71 % of the skim peptides were <20 kDa MW, with 49 % being <1.35 kDa MW, 22 % being 17–1.35 kDa MW, and 29 % being 44–670 kDa MW. Skim protein and carbohydrate contents make this fraction suitable for replacing water in ethanol fermentations, thereby improving the fermentation rate/production and the nutritional quality of distiller’s dried grains with solubles.     

Quantitative analysis of phospholipids from whey protein concentrates by high-performance liquid chromatography with a narrow-bore column and an evaporative light-scattering detector

A procedure for separation and quantitative determination of phospholipid classes by high-performance liquid chromatography with a narrow-bore column and a light-scattering detector was developed. Cerebrosides (CER), phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylcholine (PC), sphingomeyelin (SPH), and lysophosphatidylcholine (LPC) were base-line resolved, and column life was improved due to low back pressure and low alkalinity of the solvents. Solvent consumption was reduced by 80%, and the detection limit was improved more than tenfold, compared to an analytical column. A gradient elution with pH modifier was necessary for good resolution of acidic phospholipids. A binary solvent system, consisting of A: chloroform/methanol, 80:20 and B: chloroform/methanol/water/ammonium hydroxide (20%), 60:34:6:0.25, was used. Analysis was completed in 36 min, and repeated injections of the samples were possible. The method was applied to the analysis of phospholipids from whey protein concentrates (WPC). Phospholipids in WPC (75% protein) contained (%, w/w) 3.57±0.13 CER; 18.13±1.23 Pl; 4.45±0.21 PE; 7.45±0.58 PS; 30.54±1.84 PC; 35.82±1.16 SPH; and no detectable LPC.     

Composition of the lipids in human milk: A review

Recent publications on the composition of human milk are reviewed. The importance of proper sampling is discussed. Fat contents of 2.6–4.5% and cholesterol amounts of 200–650 mg/100 g fat were reported. The phytosterols in milk were increased by the consumption of these sterols. Phytosterols could contribute to the “total cholesterol” in milk if analyses are done colorimetrically. The fatty acid composition is remarkably uniform unless bizarre diets are consumed; the amounts of linoleic acid vary the most. Phospholipids contained more long chain polyunsaturated fatty acids than triacylglycerols. Scientific Contribution No. 786, Storrs Agricultural Experiment Station, University of Connecticut, Storrs, CT 06268.     

Impact of Phosphoethanolamine Reverse Micelles on Lipid Oxidation in Bulk Oils

Phospholipids are important minor components in edible oil that play a role in lipid oxidation. Surface active phospholipids have an intermediate hydrophilic–lipophilic balance value, which allows them to form association colloids such as reverse micelles in bulk oil. These association colloids can influence lipid oxidation since they create lipid–water interfaces where prooxidants and antioxidants can interact with triacylglycerols. In this study, we examined the formation of reverse micelles in a stripped oil system by dioleoyl phosphoethanolamine (DOPE) and the effect of these physical structures on lipid oxidation kinetics. The critical micelle concentration (CMC) of DOPE was approximately 200 µmol/kg oil at 45 °C. Oxidation kinetics studies showed that DOPE was prooxidative when it was above its CMC (400 and 1,000 µM), reducing the lag phase from 14 days (control) to 8 days. The addition of combinations of DOPE and dioleoyl phosphocholine (DOPC) resulted in formation of mixed micelles with a CMC of 80 µmol/kg oil at 45 °C. These mixed micelles were also prooxidative when concentrations (100 and 500 µM) were above the CMC, decreasing the lag phase from 14 to 8 days. These findings provide a better understanding of the role of phospholipids in lipid oxidation of edible oil and could contribute to better antioxidant solutions.     

Chemical and Physical Characterization of Donkey Abdominal Fat in Comparison with Cow, Pig and Sheep Fats

The objective of this research was to investigate the physicochemical properties of donkey fat. Results show that donkey fat contains 59.38 % unsaturated fatty acids, 38.37 % saturated fatty acids, and 0.21 % trans fatty acids. The sn-2 monoglyceride present in donkey fat contain 67.91 % unsaturated fatty acids and 30.97 % saturated fatty acids. Donkey fat is also characterized by a total tocopherol content of 8.59 mg/100 g fat (7.90 mg/100 g fat α-tocopherol, 0.51 mg/100 g fat β + γ-tocopherol, and 0.18 mg/100 g fat δ-tocopherol), 0.0032 mg/100 g fat cholesterol, an acid value of 0.091 KOH (mg/g), an iodine value of 76.47 g/100 g, a peroxide value of 0.68 mmol/kg, a saponification value of 193 mg/g, a refractive index of 1.4666, and a specific gravity of 0.9144. The complete melting temperature was 40 °C. The content of unsaturated fatty acids (total and sn-2) in donkey fat is higher than cow, pig and sheep, while the content of trans fatty acids is lower. The tocopherol content is also higher in donkey fat compared to cow, pig and sheep fat. Interestingly, the fat with such processing has nearly no cholesterol. Generally speaking, donkey fat could be a good animal fat for human consumption.     

Salting-out-assisted liquid–liquid extraction and reverse-phase high-performance liquid chromatographic monitoring of thiacloprid in fruits and vegetables

Salting-out-assisted liquid–liquid extraction (SALLE) was developed to extract thiacloprid (THI) from fruits and vegetables. SALLE conditions (NaCl/Na₂SO₄, pH, and solvent polarity) were investigated at various levels for the optimal recovery of THI. Meanwhile, reverse-phase high-performance liquid chromatographic (RP-HPLC) conditions were balanced over 1–100 µg/mL of THI. The optimized SALLE-RP-HPLC method offered 78.33–92.00% recovery of standard THI at an acceptable repeatability 1.81–4.30% and reproducibility 1.08–4.74%. The detection and quantification limits were found to be 0.03 and 0.05 µg/mL, respectively. The real-time analysis verifies its suitability and ease of use for the determination of THI in agricultural commodities.     

HPLC analysis of phospholipids in crude oil for evaluation of soybean deterioration

Damage to soybeans due to pre-harvest stress, storage, and export shipment has been related to an increase in the nonhydratable phospholipid content of crude oil. Phospholipids in crude soybean oil extracted from such distressed soybeans have been analyzed by gradient high-performance liquid chromatography. Crude oil was fractionated by solid phase extraction using sequential elution for recovery of phosphatides. High-performance liquid chromatography of the concentrated phospholipids was accomplished on a Lichrosorb Si-60 10 μ column, 250×4.6 mm with ultraviolet detection at 206 nm. A 20-min solvent gradient of 2-propanol/hexane/water (42∶56∶2, 51∶38∶11) gave retention profiles of phospholipid distribution (major subclasses) that changed with impact of stress applied to plant or seed. Soybeans stored at high moisture levels (16% and 20% moisture) for up to 28 days yielded oils having phosphorus contents which decreased in direct relationship to days of storage. Retention profiles were unusable for fractions isolated from oils with phosphorus content below 100 ppm. Data show that during progressive damage, the content of phosphatidylcholine and phosphatidylinositol decreased while the phosphatidic acid content increased. Presented at the Annual American Oil Chemists' Society meeting, May 8–12, 1988, Phoenix, AZ.