Study on the Chemical Nature of Sterols contained in Bulgarian Sunflower Oil

The free sterols, the sterol esters and the sterol glycosides of the crude sunflower oil as well as those of the technical lecithin, the pitch and the deodorizer distillate of the latter oil were isolated by preparative TLC. The nature of sterols contained in the isolated sterol derivatives was elucidated by GLC and combined GLC-MS. Major sterols of all examined sterol fractions are sitosterol, campesterol and stigmasterol, the amount of sitosterol being prevalent. Unknown sterol with a molecular weight of 4²⁸ is present in sterols of the crude oil and the deodorizer distillate. Sterols of the deodorizer distillate contain an unknown sterol with a molecular weight of 430. Stigmasterol is present in the sterol fraction of the deodorizer distillate in high amounts. It was established that Δ⁷-sterols of the crude oil occur only in esterified form. The hydrolysis of the sterol derivatives in acid medium leads to dehydration products known as steroid dienes and disteroid ethers. Hydrolysis without dehydration was achieved by enzyme preparations. Some sterols of the crude oil were esterified with the same higher fatty acids contained in the glycerides of the sunflower oil.     

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

The 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.     

Free and bound sterol content of sunflower, soy bean and maize oils]

The amounts of free sterols, steryl esters and steryl glycosides in sunflower, soya and maize oils as well as in the phosphatides of the same oils were determined. The refinement byproducts were enriched with sterols. The highest contents of total sterols and steryl glycosides (2,68 and 1,9%, respectively) were established in soya phosphatides followed by those in sunflower oil phosphatides (2,03 and 1,68%, respectively) and maize oil phosphatides (0,81 and 0,54%, respectively).     

Effect of water cooking on free phytosterol levels in beans and vegetables

Plant sterols (phytosterols) are known to decrease plasma cholesterol, mainly the atherogenic LDL cholesterol. In an earlier study, the thermal stability of phytosterols in vegetable oils was reported. The aim of this present work was to investigate the potential effect of cooking (30 min in boiling water), for eight plant products (broad bean, celery, cabbage, courgette, carrot, cauliflower, onion, pepper), on the free phytosterol level. Sitosterol was the most abundant sterol, followed by campesterol. After cooking, the level of total sterols was higher in all vegetables than that before cooking, if dry matter is considered. Acid hydrolysis (active for glycosylated phytosterols) yielded a higher sterol value than alkaline hydrolysis alone (active for esterified phytosterols). This indicated that studied vegetables contained appreciable amounts of steryl glycosides. Their cooking induced higher values of free phytosterols. Cooked vegetables could give better protection against cardiovascular diseases thanks to higher phytosterol levels.     

Lipids in cereals. 1. Pennisetum typhoideum

Two improved strains of Pennisetum typhoideum (‘bajra’) were found to have a free lipid content of about 5.0% and bound lipid content of about 0.5%. In the non-polar fraction, sterol esters and hydrocarbons, triglycerides, free fatty acids, free sterols and partial glycerides were present with triglycerides as the principal constituents. Polar lipids were separated by two-dimensional thin-layer chromatography and lecithin was found to be the major component. Sterol-containing glycolipids (sterol glycosides and esterified sterol glycosides) were present in appreciable amounts. Phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, lysophosphatidyl ethanolamine, lysolecithin, phosphatidic acid, poly-glycerophosphatide, mono- and di-galactosyl glycerides and cerebrosides have also been tentatively identified.     

Seed lipids of Sesamum indicum and related wild species in Sudan. The sterols

Oil extracted from seeds of different varieties of the cultivated Sesamum indicum L and three related wild species, viz S alatum Thonn, S radiatum Schum & Thonn, and S angustifolium (Oliv) Engl, were analysed for their total unsaponifiables and for the contents and composition of the three sterol fractions (desmethyl, monomethyl and dimethyl sterols). The sterols were analysed after saponification by preparative TLC, capillary GC and GC-MS of their TMS ethers. Oils from the wild species contained more unsaponifiable material (2.3-2.4%) compared with the cultivated species (1.1-1.3%). Considerable differences were observed in the total sterol contents and the relative proportions of the three sterol fractions in the oils from the four species studied. Sitosterol, campesterol, stigmasterol and Δ⁵-avenasterol were the major desmethyl sterols in all four species. The monomethyl sterol fraction consisted primarily of obtusifoliol, gramisterol, cycloeucalenol and citrostadienol. Cycloartenol and 24-methylene cycloartanol were the predominant dimethyl sterols. Variations in the composition of the three sterol fractions were observed between S indicum oils traditionally pressed by the camel-driven expellers and laboratory extracted oils from the same seeds.     

Total Plant Analyses of Sterols and Fatty Acids of the Winged Bean (Psophocarpus tetragonolobus)

Various parts of the winged bean plant, Psophocarpus tetragonolobus were analyzed for sterols and fatty acids. The major sterols were sitosterol, stigmasterol and campesterol. Sitosterol occurred in greatest amounts except in roots where stigmasterol was the predominant sterol. In seeds, behenic acid (22:0) comprised 13.5% of the total fatty acids, whereas, in the other plant parts it varied from 0.1–6.9%. Leaves contained the highest level of fatty acids, but only 22% of these fatty acids were saturated.     

Effects of low hydrostatic pressure and moderate heat on texture,pectic substances and color of carrot

Sterols in the seeds of wild Finnish blueberry (Vaccinium myrtillus) and lingonberry (Vaccinium vitis-idaea) were analyzed as TMS derivatives by gas chromatography-mass spectrometry. Free and esterified sterols constituted 0.7% and 0.3% of the seed oil of V. myrtillus, respectively, whereas in the seed oil of V. vitis-idaea the sterols in the two fractions were equally represented at 0.5-0.6%. Sitosterol (85% in V. myrtillus and 80% in V. vitis-idaea) and campesterol (7% in V. myrtillus and 6% in V. vitis-idaea) were the dominant free sterols. In comparison to free sterols, steryl esters were found to have considerably lower proportions of sitosterol (40-60%) and campesterol (3-5%), accompanied by higher levels of intermediates in the biosynthetic cascade. Although both species contained the same major sterols, they differed in their relative abundances of individual compounds. Specifically, blueberry contained a higher proportion of sitosterol and campesterol and a lower proportion of isofucosterol and cycloartenol. Comparison of berries collected from northern and southern Finland showed that growth conditions have little effect on the sterol compositions in the berries. To our knowledge this is the first report on the content and composition of phytosterols in Vaccinium sp. The results provide important information on the chemical compositions, nutritional properties, and possible chemotaxonomical characteristics of the two species.     

Sterols and Triterpenyl alcohols in common pulpwoods and black liquor soaps

The amount and composition of lipophilic extractives, and especially of sterols and triterpenyl alcohols, were analysed for six important pulpwood species, i.e., Scots pine, Loblolly and Longleaf pine, Norway spruce, Siberian larch and Silver birch. Sulphate soaps (tall oil soaps) derived from these species were also analysed. Scots pine and Loblolly pine contained the highest amounts and Siberian larch the lowest amounts of lipophilic extractives. The highest amounts of sterols were found in birch. The sterols in wood occurred mainly as esters. Sitosterol was the main sterol in all species. Isolation and analysis of the steryl esters confirmed the natural occurrence of sitostanol esters in wood. Considering the use of sitosterol or sitostanol as cholesterol-lowering component in food products, a high ratio of sitosterol to campesterol is beneficial. This ratio was high in birch and pines but clearly lower in spruce and larch. The highest ratios of sitosterol to campesterol were found in soaps from pines and birch.     

Quantitative changes in some unsaponifiable components of soya bean oil due to refining

The effects were studied of the processes of degumming, neutralisation, bleaching and deodorisation on the content and composition of the various fractions of unsaponifiables in soya bean oil. The effect of each of the various technological steps on the decrement of the investigated unsaponifiables in the processed oils was different. When compared with the crude oil, the refined soya bean oil contained less tocopherols (by 31 to 47%), sterols (by 25 to 32%) and squalene (by 15 to 37%). No significant differences were observed in the compositions of the sterol and tocopherol fractions of the crude and refined soya bean oils.     

Total lipid content, fatty acids and 4-desmethylsterols accumulation in developing fruit of Pistacia lentiscus L. growing wild in Tunisia

This research has determined oil, fatty acid and sterol contents of the Tunisian Pistacialentiscus (Lentisc) fruits during maturation. Low oil accumulation was observed during the first 35 days after the fruiting (DAF) date (from 1.83% to 2.57%). After that, two phases were distinguished (35th until the 60th and 105th to the 145th DAF), where the rate of oil accumulation increased significantly. At the last stage of maturation, the lentisc fruits had the highest percentage of lipid content, 42.54%. The changing profile of fatty acids during maturation had been marked mainly by an increase in oleic acid content (from 19.49% to 50.72%) paralleling a decrease in linoleic acid content (from 42.5% to 21.75%). At the 15th DAF, the alpha-linolenic acid was found with a maximum of 13.81%. At full maturity, the main fatty acids were oleic acid, followed by palmitic and linoleic acid. Other fatty acids were present in trace proportions, such as palmitoleic, stearic, linolenic, gadoleic and arachidic acid. In all stages of ripening only four sterols were identified and quantified. β-Sitosterol was the major 4-desmethylsterol in samples tested, followed by campesterol. Cholesterol and stigmasterol were detected in trace amounts. During the first stage of ripening, the amount of total sterols was about 5.19/100 g of oil. It decreased to 0.43/100 g in the last stage. Sitosterol and campesterol showed nearly the same profile during the ripening of P. lentiscus fruit which could be linked to the relation between these compounds during their biosynthesis.     

油脂脱臭馏出物的组成与市场前景

脱臭馏出物是脱臭工序的副产物 ,其中含有游离脂肪酸、甘油酯、臭味物质、氧化分解产物、生育酚、甾醇及甾醇酯等。目前 ,脱臭馏出物因其中富含生育酚和甾醇而具有很高的应用价值。优化脱臭系统和妥善处理收集脱臭馏出物是提高脱臭馏出物中生育酚含量的有效方法。     

Isolation of sterols from sunflower oil deodorizer distillate

A new method for isolating sterols from sunflower oil deodorizer distillate (DOD) was developed. The most salient feature of which is that, unlike most alternatives, it requires no distillation. Briefly, the method uses methanol in the presence of p-toluenesulphonic acid as catalyst to convert free fatty acids and acyl glycerides in DOD into fatty acid methyl esters (FAMEs). The resulting glycerin and excess reagents are removed by washing with water and, finally, the product is cooled in the absence of solvents to obtain sterols in 92 ± 2% purity.     

米糠油脱臭馏出物中甾醇的分析检测

测定了米糠油脱臭馏出物的主要理化指标,并利用分光光度法、HPLC法测定米糠油脱臭馏出物中甾醇含量。结果表明,米糠油脱臭馏出物中饱和脂肪酸含量为23.85%,不饱和脂肪酸含量为74.47%,其中油酸为41.38%,亚油酸为31.74%,亚麻酸为1.35%,与米糠油的脂肪酸组成基本一致;通过分光光度计法测定总甾醇含量为1.41%,通过HPLC测定豆甾醇含量为0.23%,β-谷甾醇为0.25%;GC-MS法检测米糠油脱臭馏出物中还含有3,5-二烯豆甾烷、麦角甾-5烯-3醇,还有一些不经常见到的羊毛甾醇和日耳曼甾醇。     

Lipids of berseem (Trifolium alexandrinum) seed

Berseem seed oil was fractionated into non-polar and polar components. Tentative identification was made of hydrocarbons, sterol esters, triglycerides, free fatty acids and partial glycerides in the non-polar fraction and of lysophosphatidyl choline, phosphatidyl inositol, lysophosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl ethanolamine, digalactosyl diglycerides, sterol glycosides, phosphatidic acid, monogalactosyl diglycerides, cerebrosides and esterified sterol glycosides in the polar fraction. The fatty acid constituents of the major polar and of all the non-polar lipid components are also reported.     

Influence of triglycerides and free fatty acids in milk replacers on calf performance, blood plasma, and adipose lipids

In a 4-wk study of 48 3-day-old calves we compared effects of feeding various fats or their free fatty acids in skim milk-powder based milk replacer, on calf performance, feed utilization, and blood plasma and adipose lipids. When fat was fed, calf performance and feed utilization were equivalent for tallow and coconut oil diets but markedly poorer for corn oil. Complete replacement (tallow) or one-half replacement (coconut and corn oils) of the fats with their free fatty acids reduced calf gains and feed efficiency. Tallow free fatty acids gave lower digestibilities of palmitic and stearic acid and reduced calcium absorption. Free fatty acids from both coconut and corn oils reduced diet palatability and intake; those from tallow and coconut oil markedly interfered (in vitro) with rennet clotting of milk replacers. The main lipid classes in blood plasma for all treatments were cholesteryl esters and phosphatidylcholine. High concentrations (56 to 87%) of linoleic acid occurred in cholesteryl esters for all diets despite low concentrations of linoleic acid in the tallow and coconut oil diets.     

米糠油及其脱臭馏出物中生育酚和生育三烯酚的分析检测

对米糠油及其脱臭馏出物中生育酚及生育三烯酚含量进行检测分析,结果表明,米糠来源和米糠油精炼工艺对米糠油及其脱臭馏出物中α、β、γ、δ-生育酚和生育三烯酚的含量有显著影响。米糠毛油中生育三烯酚占维生素E总量的60%～70%,脱臭馏出物中生育三烯酚占维生素E总量的25%～40%,米糠油脱臭馏出物维生素E总量中生育三烯酚的含量较米糠毛油有较大的损失。通过对米糠油脱臭馏出物不皂化物的分析检测可知,米糠油脱臭馏出物中主要甾醇的种类为豆甾醇、菜油甾醇、谷甾醇,总甾醇含量很少,仅为0.32%;除此之外,还有少量日耳曼甾醇、羊毛甾醇、3,5-二烯豆甾烷等。     

Lipid composition of the liver oil of the ray, Himantura bleekeri

If rays are traditionally fished for their caudal fins, the rest of the body is wasted, except part of the skin that can be transformed into leather. Liver oil of the ray, Himantura bleekeri, was characterized in terms of lipid class composition and fatty acid profile. Liver oil content was high and represented 54% of the liver weight (w/w). Neutral lipids were predominant (92%), major components being triacylglycerols (63%). Other neutral lipids identified were hydrocarbons, sterol esters, mono- and di-acylglycerols, free fatty acids, sterols and glyceryl ethers. Polyunsaturated fatty acids of the n−3 series, namely eicosapentaenoic and docosahexaenoic acids, were high (4% and 16%, respectively). Cholesterol was the major component in the sterol fractions (free or esterified). Hydrocarbons were up to 30 carbons and squalene was present at the level of 22%. Thus, this liver oil proved to be an adequate source of n−3 fatty acids and other valuable lipidic compounds.     

Über die Extraktstoffe des Stammaterials der Kletterpalme Korthalsia rigida Blume

The extractives from the stems ofKorthalsia rigida Blume were isolated by successive extractions with solvents of increasing polarity. The lipophilic extractives mainly consist of free fatty acids, glycerides and sterol esters besides of free sterols. Principal components of the acids (free and esterified) are palmitic, linolenic, and linolic acid. Furthermore, very small amounts of dehydroabietic acid and three other diterpene acids have been identified as free acids. In the mixture of the free acids from the ether extract a fairly high amount of p-hydroxy benzoic acid is present. The bulk of the extraneous components is present in the polar extract fractions which contain besides of simple sugars mainly condensed tannins and related natural pholobaphenes.     

Analysis of free and esterified sterols in edible oils by online reversed phase liquid chromatography-gas chromatography (RPLC-GC) using the through oven transfer adsorption desorption (TOTAD) interface

An online reversed phase liquid chromatography-gas chromatography (RPLC-GC) method is proposed to quantify free, total and esterified sterols of edible oils. To determine free sterols the diluted oils are injected into the liquid chromatograph, where free sterols are separated from triglycerides and the sterol fraction is automatically transferred to the gas chromatograph to be analysed. To determine total sterols the samples were saponified with potassium hydroxide in ethanolic solution and the unsaponifiable fraction was extracted with diethyl ether. The extract was then analysed by RPLC-GC, avoiding the laborious thin layer chromatography step used in the Official European Union (EU) Method. The relative standard deviations (RSDs) from the absolute peak area varied from 7.6% to 15.8%. Limits of detection (LODs) were less than 8.5 mg/kg. No variability in retention time was observed. The method was applied to the determination of total sterols in edible oil samples and the results were compared with those obtained with the Official EU Method. Good agreement was found between both methods, except in the case of campesterol.