Sterol Ester Fraction Research Articles

Analysis of the Lipid Component and the Sterol Ester Fraction for the Detection of Soft Wheat in Durum Wheat Flour and Pasta

Food adulteration consists of changing the original structure of a food, and so, by its definition, it is a process not admitted by law. Adulterations can not only have commercial consequences, but also hygienic and nutritional ones, and in some cases, they can cause a serious danger to public health. Therefore, it is of great interest to understand and identify the modifications that alter the original chemical composition of a food item (nutrition label). Among the food processing sectors, the pasta food chain is a fascinating production process, which finds its roots in a mixture of a few, simple ingredients; in particular, in its basic formulation to produce pasta, exclusively durum wheat mixed with water is used, while soft wheat and therefore the flour obtained from it are destined for bakeries and the confectionery industry. In this work, a procedure was developed that allows the detection of the possible presence of soft wheat in durum wheat-based products, both in the flour and after the pasta-making process. It is to point out that this adulteration is only commercial fraud and there are no consequences for people’s health. In detail, the method was based on the isolation of the lipid fraction of flours and pastas and using the gas chromatographic analysis of the sterol ester fraction, which were not altered during the pasta-making phase, because they have very high boiling points. Based on the evaluation of some specific ratios between sterol esters, it was possible to trace the percentage of soft wheat present in a mixture with durum wheat, both in flour products and pastas.

Role of dietary phospholipids and phytosterols in protection against peptic ulceration as shown by experiments on rats.

Geographically the prevalence of duodenal ulceration is related to the staple foods in the diet in regions of developing countries where the diet is stable. It is higher in regions where the diet is based on milled rice, refined wheat or maize, yams, cassava, sweet potato, or green bananas, and is lower in regions where the staple diet is based on unrefined wheat or maize, soya, certain millets or certain pulses. Experiments on rat gastric and duodenal ulcer models showed that it was the lipid fraction in staple foods from low prevalence areas that was protective against both gastric and duodenal ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs). It also promoted ulcer healing. The lipid from the pulse, Dolichos biflorus, horse gram which was highly protective was used to identify the fractions with protective activity in the lipid. The protective activity lay in the phospholipid, sterol and sterol ester fractions. In the phospholipid fraction phosphatidyl choline (lethicin) and phosphatidyl ethanolamine (cephalin) were predominant. In the sterol fraction the sub-fractions showing protective activity contained β-sitosterol, stigmasterol, and an unidentified isomer of β-sitosterol. The evidence from animal models shows that certain dietary phospholipids and phytosterols have a protective action against gastroduodenal ulceration, both singly and in combination. This supports the protective role of staple diets in areas of low duodenal ulcer prevalence and may prove to be of importance in the prevention and treatment of duodenal ulceration and management of recurrent ulcers. A combination of phospholipids and phytosterols could also play an important role in protection against ulceration due to NSAIDs.

Dietary Phosphilipids and Sterols Protective against Peptic Ulceration

The prevalence of duodenal ulceration in regions of developing countries with a stable diet is related to the staple food(s) in that diet. A higher prevalence occurs in areas where the diet is principally milled rice, refined wheat or maize, yams, cassava, sweet potato or green bananas, and a lower prevalence in areas where the staple diet is based on unrefined wheat or maize, soya, certain millets or certain pulses. Experiments using animal peptic ulcer models showed that the lipid fraction in foods from the staple diets of low prevalence areas gave protection against both gastric and duodenal ulceration, including ulceration due to non-steroidal anti-inflammatory drugs (NSAIDs), and also promoted healing of ulceration. The protective activity was found to lie in the phospholipid, sterol and sterol ester fractions of the lipid. Amongst individual phospholipids present in the phospholipid fraction, phosphatidyl ethanolamine (cephalin) and phosphatidyl choline (Lecithin) predominated. The sterol fraction showing activity contained β-sitosterol, stigmasterol and an unidentified isomer of β-sitosterol. The evidence shows that dietary phytosterols and phospholipids, both individually and in combination, have a protective effect on gastroduodenal mucosa. These findings may prove to be important in the prevention and management of duodenal and gastric ulceration including ulceration due to NSAIDs.

Lipid Structure of Lallemantia Seed Oil: A Potential Source of Omega‐3 and Omega‐6 Fatty Acids for Nutritional Supplements

AbstractThe lipid composition of the seed oil of three varieties (L‐74, VIR‐11 and BGR‐455) of Lallemantia iberica Fisch. & Mey. (Lamiaceae) harvested in Bulgaria was examined in detail. Triacylglycerols (TAG >90%), phospholipids (<3%), sterol esters (~0.2%), and accompanying compounds—sterols (~0.3%) and tocopherols (336–499 mg/kg)—were determined for the first time. In addition, the specific distribution of fatty acids between the lipid classes was elucidated. Nineteen TAG species were unambiguously identified and quantified and of these the highly unsaturated trilinolenin, dilinolenyl linoleate and dilinolenyl palmitate comprised 59% of the total TAG. Phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine were the main phospholipids. Beta‐sitosterol was the main sterol component, followed by campesterol and stigmasterol. Gamma‐tocopherol predominated (>90%) in the tocopherol fraction. Palmitic acid (16:0) was the major fatty acid of the phospholipids and oleic acid (cis 9‐18:1) dominated in the sterol ester fraction. The three varieties have similar lipid compositions with BGR‐455 being slightly more saturated. Due to its composition, Lallemantia oil might compete successfully with flax and other plant oils as a source of linolenic fatty acid in industrial and dietary applications.

Dietary supplementation of obese children with 1000 mg alpha-linolenic acid per day: a placebo-controlled double blind study

Enhanced dietary intake of omega-3 fatty acids may benefit persons with increased cardiovascular risk, among them obese subjects. Incorporation of omega-3 fatty acids into the plasma lipids is a prerequisite to achieve the favorable effects; however, only very few data are available on the dose of omega-3 fatty acid supplementation in children. The aim of our study was to examine the effects of the consumption of a diet supplemented with 1000 mg alpha-linolenic acid daily on plasma lipids in obese children. In this two times six-week-long, placebo-controlled, crossover study, 9 obese children (age: 13.1 [2.5] years, body mass index: 31.2 [6.2] kg/m 2 ), median [IQR]) incorporated into their diet one egg and one meatball (50 g) per day from hens fed diets containing flaxseed oil, i.e. supplementary dietary intake of 1000 mg alpha-linolenic acid per day was provided. The fatty acid composition of plasma lipids was determined by high-resolution gas-liquid chromatography. Tendencies of increase were observed in the alpha-linolenic acid content of plasma lipids in the phospholipid, triacyl-glycerine and sterol-ester fractions after the supplementation with alpha-linolenic acid. In the non-esterified fatty acid fraction, the values of alpha-linolenic acid were significantly higher after the supplementation (0.11 [0.08] versus 0.14 [0.20], % weight/weight, p < 0.05), indicating the beginning of the accumulation of alpha-linolenic acid in plasma lipids. In obese children a six-week-long supplementation of the diet with 1000 mg alpha-linolenic acid per day increased significantly the contribution of omega-3 fatty acids only to the non-esterified fatty acids of plasma lipids, but had no significant effect on the esterified fractions. Increase of the dose of supplementation may be needed to influence omega-3 fatty acid status in obese children.

Low contribution of n-3 polyunsaturated fatty acids to plasma and erythrocyte membrane lipids in diabetic young adults

Hypoinsulinemia characteristic to type 1 diabetes may theoretically inhibit the conversion of essential fatty acids to their longer-chain metabolites. Fatty acids were determined in plasma and erythrocyte membrane lipids in young diabetic adults ( n=34) and in age-matched healthy controls ( n=36). Values of linoleic acid (56.01 [5.02] versus 51.05 [7.32], % by wt, median [range from the first to the third quartile], P<0.00l) and arachidonic acid (AA) (11.17 [2.98] versus 9.69 [1.95] P<0.001) were significantly higher in diabetic subjects than in controls. However, α-linolenic acid values did not differ, and docosahexaenoic acid (0.43 [0.12] versus 0.57 [0.29], P<0.01) values were significantly lower in diabetic than in control subjects. Significant inverse correlations were found between AA and hemoglobin A 1c values in the phospholipid ( r=−0.40, P<0.05) and sterol ester ( r=−0.40, P<0.05) fractions. The data obtained in the present study suggest that the availability of n-3 long-chain polyunsaturated fatty acid may be reduced in young diabetic adults.

Fatty Acids, Triacylglycerols, and Sterols in Neem Oil (Azadirachta Indica A. Juss) as Determined by a Combination of Chromatographic and Spectral Techniques

Quantitative thin‐layer chromatography in silver ion and reversed phase modes, gas chromatography, gas chromatography–mass spectrometry, and 13C nuclear magnetic resonance spectrometry were employed to determine the lipid composition in neem (Azadirachta indica A. Juss) kernel oil. Thirteen fatty acids and 25 triacylglycerols species were identified and quantified. The seven main triacylglycerols species were found in almost equal amounts in the range 7–10%. Saturated fatty moieties occupied positions 1‐ and 3‐ in the triacylglycerol molecule, oleic acid was almost equally distributed, and linoleic acid predominantly occupied position 2. Sitosterol, stigmasterol, campesterol, and fucosterol were the main components in free sterol and sterol ester fractions.

Sterols of the heterotrophic dinoflagellate, pfiesteria piscicida (dinophyceae): is there a lipid biomarker?1

Within U.S. waters, blooms of the dinoflagellate, Pfiesteria piscicida, have been recorded on an almost regular basis in the Chesapeake Bay and surrounding mid‐Atlantic regions for the last two decades. Despite the apparent significance of such blooms to the environment and human health and the attendant economic consequences, little work has addressed the physiology and biochemistry, particularly that of sterol composition, of P. piscicida. GC‐MS characterization of trimethylsilyl ether derivatives of sterols from free sterol and sterol ester fractions was performed in an effort to determine whether P. piscicida produces unique sterols that may serve as potential biomarkers. This characterization revealed that like most dinoflagellates, the majority of sterols was present as free sterols. Furthermore, the profile of free sterols was found to resemble those of photosynthetic dinoflagellates, with the dominant compound being the previously reported dinoflagellate sterol, dinosterol. A number of other 4α‐methyl‐substituted sterols and steroidal ketones common to other dinoflagellates were also identified. No strong candidate(s) for a unique sterol biomarker was present.

Analysis of free and esterified sterols in fats and oils by flash chromatography, gas chromatography and electrospray tandem mass spectrometry

A method for the analysis of free and esterified sterols has been developed. Fat or oil samples were separated on solid-phase extraction silica gel columns into a sterol ester fraction, a fraction of triacylglycerols, and a free sterol fraction containing partial acylglycerols and residual triacylglycerols. Sterol esters and acylglycerols of the free sterol fraction were transesterified to methyl esters. The fatty acid methyl esters from sterol ester fraction and the free sterols from sterol ester fraction and free sterol fraction were determined by GLC. Precursor ion electrospray MS–MS of sterol fragment ions of sterol ester fractions were recorded and used for determination of sterol ester proportions in butterfat and vegetable oil samples.

Increased control of the sheep biting louse Bovicola (Damalinia) ovis with deltamethrin formulated in a fractionated wool grease carrier

The synthetic pyrethroid deltamethrin (DM) containing a trace of [ 14C]-DM was formulated with non-oxidised sterol and wax ester fractions (F1) of wool grease and as the commercial preparation ‘Clout-S’. These were applied as a ‘backline’ strip to sheep immediately after shearing and the concentration of [ 14C]-DM at meridians adjacent to the application strip and at 1/4 and 3/4 of the dorsal–ventral distance was determined. The F1 formulation resulted in significantly greater lateral spread of DM with less remaining at the application site (66±8% of dose) 98 days after treatment compared to ‘Clout-S’ (94±3% dose). Autoradiographic examination of treated wool demonstrated that there was more DM in the lower half of the wool staple when formulated in F1 compared to ‘Clout-S’. Greater mortality occurred when sheep biting lice Bovicola (Damalinia) ovis were exposed in vitro to wool containing DM from F1 compared to ‘Clout-S’ treated sheep. In field trials there was increased efficacy against synthetic pyrethroid resistant B. ovis with F1 formulation than with ‘Clout-S’. The study has demonstrated that synthetic pyrethroid availability, and therefore efficacy, can be significantly increased when the insecticide is formulated in a ‘carrier’ with the physicochemical characteristics of wool grease.

Occurrence of Potential Brassinosteroid Precursor Steroids in Seeds of Wheat and Foxtail Millet

L.) and foxtail millet (Setaria italica Beauv.) were found by GC-MS to contain, in addition to bulk sterols, 4-en-3-one steroids including 24-ethylcholesta-4,24(28)Z- dien-3-one (a new steroid), 24-methylcholest-4-en-3-one, 24-ethylcholesta-4,22E-dien-3-one and 24-ethylcholest-4-en-3-one, as well as 5α-steroidal 3-one compounds including 24-methyl-5α-cholestan-3-one, 24-ethyl-5α-cholestan-3-one and 24-ethyl 5α-cholest-22E-en-3-one (in S. italica only). Analysis of free sterol and steryl ester fractions indicated that campestanol and sitostanol were present at high levels in both seeds. These results suggest that the seeds of T. aestivum and S. italica synthesize campestanol from campesterol via 24-methylcholest-4-en-3-one and 24-methyl-5α-cholestan-3-one as has already been demonstrated in Arabidopsis thaliana L., and also produce sitostanol from sitosterol via 24-ethylcholest-4-en-3-one and 24-ethyl-5α-chotestan-3-one. Biosynthetic relationships of campestanol and sitostanol with C28 and C29 brassinosteroids are discussed.

Basal concentrations of free and esterified monohydroxylated fatty acids in human blood platelets

Monohydroxylated fatty acids (HO-FA), namely 12-hydroxyeicosatetraenoic and 12-hydroxyheptadecatrienoic acids, are enzymatically formed in response to platelet activation. Different techniques, including gas chromatography (GC) and liquid chromatography-mass spectrometry (LC-MS), have been described to measure HO-FA in activated cells, but they are not well-adapted to resting cells. Measurements of free and esterified HO-FA at basal concentration require the prevention of platelet activation. For this purpose, such an activation was minimized by adding various inhibitors to the anticoagulant. Platelet recovery was greater in the protected group than in controls (473 x 10(9) +/- 4.0 x 10(9) platelets/L vs 410 x 10(9) +/- 4.53 x 10(9) platelets/L, respectively) (mean +/- SEM, n = 9, P < 0.05). Lipids were extracted and immediately hydrogenated to avoid fatty acid autoxidation occurring during the workup. Unesterified and esterified HO-FA were analyzed by GC-MS, and the former were lower in the protected group (1.52 +/- 0.84 pmol/10(9) platelets) than in the unprotected one (12.63 +/- 10.52 pmol/10(9) platelets) (mean +/- SEM, n = 9, P < 0.05). Interestingly, only traces of HO-FA were detected in both the triglyceride and sterol ester fractions, and they were also weakly esterified in phospholipids.

Sterol and fatty acid composition of neutral lipids of Paratenuisentis ambiguus and its host eel.

The sterol composition of free sterol and steryl ester fractions of the fish parasite Paratenuisentis ambiguus was determined. In addition, the fatty acid composition of various neutral lipid classes, i.e., wax esters, steryl esters, triacylglycerols and free fatty acids, as well as the composition of the 1-O-alkyl moieties of total ether glycerolipids of the parasite, were investigated. The results of these studies were compared with those obtained on the intestinal tract tissue of its host, the eel (Anguilla anguilla). Cholesterol is the major sterol in both P. ambiguus and A. anguilla. However, the sterols of P. ambiguus contain high proportions (> 20%) of other sterols, such as campesterol and various dehydrosterols. [e.g., 7-dehydrocholesterol and cholesta-5,22(E)-dienol]. The presence of these minor sterols agrees with the known biotransformations of exogenous sterols in various helminths. Considerable differences are found in the fatty acid composition of neutral lipid fractions, as well as the total lipid extract from the endoparasite as compared to the host tissue. In particular, eicosapentaenoic acid (20:5n-3), other polyunsaturated fatty acids, such as 20:4n-6, 22:5n-3 and 22:6n-3, as well as long-chain saturated fatty acids, such as 20:0, are generally enriched in the neutral lipid fractions of the parasite as compared to those of infected eel intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for a mounting sex pheromone in the brown ear tick Rhipicephalus appendiculatus, Neuman 1901 (Acari: Ixodidae).

The presence of a mounting sex pheromone was demonstrated on the surface of fed female Rhipicephalus appeniculatus. This pheromone, which is present on the female cuticle, allows the male to recognise the female. The pheromone was removed by cleaning the female in hexane, resulting in the loss of male mating behaviour in in vitro experiments. Male mating behaviour was resumed when extract made from fed female cuticle was replaced on cleaned females. When the extract was transferred to inanimate objects typical male mating behaviour was released. Preliminary chemical analyses indicated that the active component of the extract was contained in the sterol ester fraction of the extract.

Biochemical composition and fatty acid content of fertilized eggs, yolk sac stage larvae and first-feeding larvae of the Senegal sole ( Solea senegalensis Kaup)

Changes in biochemical composition and fatty acid content were investigated during the early development of the Senegal sole ( Solea senegalensis Kaup). The pattern of lipid utilization in this rapidly developing marine flatfish species favored neutral lipids, particularly triacylglycerol and sterol ester fractions. Fertilized eggs and yolk sac larvae were richer in neutral lipids, which decreased during development. In contrast, a significant increase occurred to proportions of phospholipids, mainly due to significant increases in minor classes such as phosphatidylserine, phosphatidylinositol and phosphatidic acid/cardiolipin, whereas major phospholipid classes such as phosphatidylcholine and phosphatidylethanolamine remained constant during development. Saturated and monounsaturated fatty acids such as 16:0, 16:1 n−7, 18:1 n−9 and 18:1 n−7 were utilized to a greater extent than polyunsaturated fatty acids as energy substrates. A requirement for long-chain polyunsaturated fatty acids such as eicosapentaenoic acid (20:5 n−3) and docosahexaenoic acid (22:6 n−3) is likely since no evidence of bioconversion from their precursors was found. A requirement for arachidonic acid (20:4 n−6) is also suggested as it is specifically retained throughout development.

Chemical composition of tobacco seeds (Nicotiana tabacum L) from Argentina

AbstractThe lipid constituents, free fatty acids, triglycerides, sterol esters and free sterols of 11 cultivars of tobacco from Argentina were investigated by gas‐liquid chromatography. Palmitic, oleic and linoleic acids were the major components in all fractions studied. Sitosterol was the main component of the free sterol and sterol ester fractions. Oil and protein contents, as well as some physicochemical characteristics of the oils, are also reported.

Temperature Preconditioning Increases Tolerance to Chilling Injury and Alters Lipid Composition in Zucchini Squash

Temperature preconditioning at 15°C for 2 d effectively delayed the development of chilling injury in zucchini squash (Cucurbita pepo L., cv. ‹Ambassador›) storage at 5°C. Chilling at 5°C resulted in loss of phospholipids, including PC, PE, PG, and PI. These losses were reduced by temperature preconditioning treatment. The degree of fatty-acid unsaturation of phospholipids declined during storage, but was higher in treated squash than in the controls. Temperature preconditioning treatment also reduced losses of the galactolipids MGDG and DGDG during the cold storage. Spinasterol and Δ7-stigmastenol were the two predominant sterols, constituting more than 75 % of both the free sterol and steryl ester fractions. The ratio of free sterol/total phospholipids increased during the cold storage. The increase of this ratio was suppressed by the temperature preconditioning treatment. These results may indicate that acclimation to chilling storage temperatures involves protection of membranes from chilling-induced degradation of glycerolipids.

Sterol metabolism in the nematodePanagrellus redivivus

AbstractPanagrellus redivivus was propagated in media containing three structurally different sterols: 7‐dehydrocholesterol, campesterol or stigmastanol. Nematodes propagated with 7‐dehydrocholesterol contained mostly lathosterol and 7‐dehydrocholesterol. Nematodes propagated with campesterol contained mostly cholesterol and cholestanol. Nematodes propagated with stigmastanol contained mostly cholestanol. The sterol ester fraction was enriched with 4α‐methylsterols and contained the same sterols as the free sterol fraction except for nematodes propagated with 7‐dehydrocholesterol, where no dietary sterol was found in the ester fraction.P. redivivus is capable of reducing the Δ5‐bond, C−24 dealkylation and methylating the sterol nucleus at C−4.

Lipid Composition of Preaestivating and Aestivating Adult Egyptian Alfalfa Weevil, Hypera brunneipennis (Coleoptera: Curculionidae)

Body weight of adults of the Egyptian alfalfa weevil, Hypera brunneipennis (Boheman), declined approximately 40% during the first 3 mo of aestivation, but there was little or no lipid utilization. By the end of aestivation, however, lipid content had declined approximately 50%. The majority of fatty acids recovered from preaestivating and aestivating H. brunneipennis adults were C 18. Oleic acid (18:1) was generally the most abundant fatty acid, with the greatest percentage recovered from the sterol ester fraction. Linolenic (18:3 n3) was the next most abundant acid and was found largely in the free fatty acid and monoglyceride fractions. C 18 was present only in low amounts in alfalfa foliage. It appears that these C18 acids are, at least partially, synthesized by H. brunneipennis . Aestivating H. brunneipennis apparently uses fatty acids generally rather than specifically.

Free and conjugated desmethylsterol composition of Zea mays hybrids exposed to mild osmotic stress

Five hybrids of Zea mays (A619 × H60, B73 × MO17, B73 × PA91, B73 × VA17. A632 × H96) were grown hydroponically at osmotic potentials of ‐0.1 (control), ‐0.4 and ‐0.6 MPa. Dry weights of hybrids B73 × VA17 and A632 × H96 decreased significantly at ‐0.4 and ‐0.6 MPa. Few changes were observed in the free sterol, steryl glycoside and steryl ester fractions. However, steryl esters of the roots and stems of osmotically treated plants declined in most of the hybrids. The stigmasterol to sitosterol ratio increased in all three steryl fractions in the roots of B73×VA17 and A632×H96 as a result of the osmotic treatments. B73×VA17 and A632×H96 also exhibited the greatest initial electrolyte leakage when leaf dises were subjected to osmotic stress. A632×H96 and possibly B73×VA17 were less tolerant to osmotic treatments than the other hybrids. Modification of sterols may reflect initial events that lead to the stabilization or destabilization of cellular membrances which in turn may affect the tolerance of plants to stressful environments.