Focused microwave-assisted Soxhlet extraction of acorn oil for determination of the fatty acid profile by GC–MS. Comparison with conventional and standard methods

A study of the feasibility of focused microwave-assisted Soxhlet extraction of acorn oil and comparison of results from analysis of trans fatty acids in the oil thus obtained with those for oils obtained by use of other methods commonly used for oil extraction are reported here. The proposed method was optimized by means of a 21-experiment screening design to determine, by means of a reduced number of experiments, which factors affect both extraction efficiency and the degree of unsaturation of the fatty acids in the oil. The proposed method enables total extraction of the fatty acids in 30 min, which is much less than the time required by the Folch (4.5 h), Soxhlet (16 h), and ISO (8 h) reference methods and the stirring–extraction method (56 h). The efficiency of extraction achieved by use of the proposed method is statistically equivalent to that achieved by use of the other methods; the composition of the extracts obtained by use of the proposed method and the Folch and stirring reference methods are also statistically similar. No trans fatty acids were present in the extracts obtained by use of the Folch, stirring, and proposed methods but they were detected in the extracts obtained by use of both the Soxhlet and ISO methods.     

气相色谱法与麻油纯度试验法在芝麻油掺伪鉴定中的应用

用气相色谱法和麻油纯度试验法对芝麻油掺伪情况进行分析。用气相色谱法分析脂肪酸组成,测定植物油中的主要脂肪酸,来确定是何种油或掺入其它何种植物油;麻油纯度试验法用于定量。两者可结合起来使用。     

在线热辅助甲基化-气相色谱法分析棉籽仁中的脂肪酸组成

建立了分析棉籽仁中脂肪酸组成的在线热辅助甲基化-气相色谱法。将0.3 mg棉籽仁样品与2 μ L三甲基氢氧化硫（0.2 mol/L）加入裂解器,在350℃下进行甲基化反应,通过气相色谱仪进行分离分析,共检测到8种脂肪酸甲酯成分,分别为亚油酸（C18：2）、油酸（C18：1）、棕榈酸（C16：0）、硬脂酸（C18：0）、肉豆蔻酸（C14：0）、棕榈油酸（C16：1）、花生酸（C20：0）和二十二酸（C22：0）,不饱和脂肪酸的相对含量为66.30%~72.54%,其中亚油酸的相对含量为43.20%~53.61%,相对峰面积的相对标准偏差（RSD）小于10%（n=5）。通过分析5组棉籽仁样品与3种食用油中的脂肪酸组成,结果表明不同产地的棉籽仁中的脂肪酸组成差异不明显,且棉籽仁中的脂肪酸组成与玉米油最为接近,相似度为0.960~0.992。该方法简单、快速、准确,适合分析棉籽仁中的脂肪酸组成。     

甘油酯化降酸反应过程研究

研究了酸化油甘油酯化反应降低酸值的反应过程,考察了温度、甘油与酸化油中游离脂肪酸物质的量比和单甘酯含量对反应的影响,发现甘油单甘酯能明显促进酯化反应的进行。对二元体系甘油三酯-甘油、油酸-甘油和单甘酯-甘油的液-液相平衡以及甘油-单甘酯-油酸三元体系液-液相平衡的分析结果表明,甘油单甘酯的存在能够显著提高甘油与脂肪酸的相互溶解。这较好地解释了甘油单甘酯在酸化油酯化反应中的促进作用。     

Determination of Free Fatty Acids in Natural Oils and Alkyd Resins by High Performance Liquid Chromatography

Abstract

Mixtures of free fatty acids in natural oil and alkyd resin samples have been analyzed using a μBondapak Free Fatty Acid column in conjunction with a ternary mobile phase. Variation of the mobile phase composition allows ‘‘fingerprinting'’ as well as quantitation of the fatty acid components. Samples can be analyzed in ten minutes by this method. The results of the application of this technique to the identification of oil sources of fatty acids as well as the production of fatty acids during alkyd resin synthesis are given. Good agreement is observed for fatty acid compositions determined via HPLC with those obtained by gas chromatographic methyl ester analysis.     

Compositions of the seed oil of the Borago officinalis from Iran

In order to investigate the composition of borage (Borago officinalis L.) seed oil, this research was performed under the field conditions at Shahriyar and Garmsar zones, Iran during the 2012 planting year. The oil yield of borage was 31.46% and 33.7% at Shahriyar and Garmsar zone, respectively, and nine and eight fatty acids were identified in the seed oil of borage at Shahriyar and Garmsar, respectively – palmitic, linoleic, stearic and γ-linolenic acids were dominant in the seed oil of borage from both zones. Unsaturated fatty acid content was more than the saturated fatty acids in both zones. The ratio of linoleic acid and α-linolenic acid in the borage cultivated at Shahriyar and Garmsar zones was 2.13 and 2.29. The fatty acid profile of Garmsar borage, oleic and oleic/linoleic acid ratio, increased. Locations with different ecological conditions resulted in changes in both seed oil content and fatty acid profile of borage.     

<em>In Vitro</em> Anti-diabetic Activities and Chemical Analysis of Polypeptide-k and Oil Isolated from Seeds of <em>Momordica charantia</em> (Bitter Gourd)

The amino acid and fatty acid composition of polypeptide k and oil isolated from the seeds of Momordica charantia was analysed. The analysis revealed polypeptide k contained 9 out of 11 essential amino acids, among a total of 18 types of amino acids. Glutamic acid, aspartic acid, arginine and glycine were the most abundant (17.08%, 9.71%, 9.50% and 8.90% of total amino acids, respectively). Fatty acid analysis showed unusually high amounts of C18-0 (stearic acid, 62.31% of total fatty acid). C18-1 (oleic acid) and C18-2 (linoleic acid) were the other major fatty acid detected (12.53% and 10.40%, respectively). The oil was devoid of the short fatty acids (C4-0 to C8-0). Polypeptide k and oil were also subjected to in vitro α-glucosidase and α-amylase inhibition assays. Both polypeptide k and seed oil showed potent inhibition of α-glucosidase enzyme (79.18% and 53.55% inhibition, respectively). α-Amylase was inhibited by 35.58% and 38.02%, respectively. Collectively, the in vitro assay strongly suggests that both polypeptide k and seed oil from Momordica charantia are potent potential hypoglycemic agents.     

The Role of Lignocellulosic Composition and Residual Lipids in Empty Fruit Bunches on the Production of Humic Acids in Submerged Fermentations

The aim of this research was to study the production of humic acids (HA) by Trichoderma reesei from empty fruit bunches (EFBs) of palm oil processing, with a focus on the effects of lignocellulosic content and residual lipids. EFBs from two different soils and palm oil producers were previously characterized about their lignocellulosic composition. Submerged fermentations were inoculated with T. reesei spores and set up with or without residual lipids. The results showed that the soil and the processing for removal of the palm fresh fruits were crucial to EFB quality. Thus, EFBs were classified as type 1 (higher lignocellulosic and fatty acids composition similar to the palm oil and palm kernel oil) and type 2 (lower lignocellulosic content and fatty acids composition similar to palm oil). Despite the different profiles, the fungal growth was similar for both EFB types. HA production was associated with fungal growth, and it was higher without lipids for both EFBs. The highest HA productivity was obtained from type 1 EFB (approximately 90 mg L⁻¹ at 48 h). Therefore, the lignocellulosic composition and the nature of the residual lipids in EFBs play an important role in HA production by submerged fermentation.

     

Determination of the triglyceride composition of pomegranate seed oil by reversed-phase HPLC and spectrophotometry

An increment approach and the control of the position of convergence points is proposed for the determination of the fatty acid composition of triacylglycerides (TAGs) from seed oil of pomegranate. reversed-phase HPLC under conditions ensuring the absence of artifacts is shown to distinguish TAGs formed by isomer-conjugated octadecatrienic acids.     

Gas-chromatographic fatty-acid fingerprints and partial least squares modeling as a basis for the simultaneous determination of edible oil mixtures

Partial least squares modeling and gas-chromatographic fatty-acid fingerprints are reported as a method for the simultaneous determination of cottonseed, olive, soybean and sunflower edible oil mixtures. In this work, two sets of three- and four-component combinations of oils were prepared, hydrolyzed and the obtained free fatty acids analyzed by gas chromatography (GC) without any further derivatization. The normalized percentages of the myristic (14:0), palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2) and linolenic (18:3) acids were chromatographically measured in samples and used for constructing calibration matrix. The cross-validation method was used to select the number of factors and the proposed methods were validated by using two sets of synthetic oil mixture samples. The relative standard error for each oil in mixture samples was less than 10%. This approach allows determining possible adulteration in each of the four edible oils.     

Determination of the fatty-acid composition of soybean oil by high-pressure liquid chromatography

A method for determining the fatty-acid composition of soybean oil by using high-pressure liquid chromatography (HPLC) is discussed and compared with the determination using gas chromatography. The oil is saponified and an aliquot is treated directly to form the p-bromophenacyl esters of the fatty acids, which are separated by gradient-elution HPLC. It is shown that glycerol does not interfere with the esterification, thus obviating the solvent extraction previously used to isolate fatty acids from biological samples.     

Epoxy and hydroxy acids of the seed oil ofGaleopsis bifida

The lipids of the seeds of the hemp nettle, which is toxic for ruminants have been studied. The composition of the fatty acids of five classes of lipids and the position-species composition of the triacylglycerols have been determined. The presence of epoxyacyl- and hydroxyacylglycerols in the oil and the structures of the acids of these lipids have been established. Squalene has been isolated from the oil.     

Thermal stability studies of some cerrado plant oils

Thermogravimetry technique is useful to determine the thermal stability of vegetable oils. In this paper some vegetable oils obtained from brazilian Cerrado native plants were studied based on their high oleic acid content. Amburana, baru and pequi pulp oils presented higher yield of extraction compared to soybean oil. The thermal stability of oils in nitrogen was very close hence their fatty acid composition was very similar. Amburana and baru oils have major amount of unsaturated fatty acids, especially linoleic acid and pequi pulp oil has the highest short chain fatty acid content which can explain its lowest thermal stability in synthetic air.     

Evaluation of a rapid method for preparation of fatty acid methyl esters for analysis by gas-liquid chromatography

The major limitation to fatty acid analysis by gas-liquid chromatography is associated with preparation of fatty acid methyl esters (FAME). In the present study, FAME preparations were made from plant oils (corn, olive, sunflower), sunflower oil margarine, lard and various animal tissue fats by a rapid transesterification involving tetramethylammonium hydroxide in methanol, and also by a longer conventional saponification-esterification method. Fats from animal (beef, mutton, pork) adipose tissues were extracted by a simpler modified procedure and also by the Folch method prior to the rapid and the conventional FAME preparations, respectively. FAME analysis on a gas-liquid chromatograph equipped with a Silar 10C glass capillary column indicated similar fatty acid composition of a given fat or oil, whether FAME was prepared by the rapid or the longer conventional method. The data obtained by both methods were very highly correlated for all the fats (r = 0.9895 - 0.9999). However, the rapid method showed a tendency for enhanced recoveries of lower chain fatty acids (e.g. 14:0), and also of unsaturated C18 isomers. Possibly, losses of fatty acids that occurred during the lengthy fat extraction, fatty acid esterification or ether-evaporation FAME concentration steps (conventional method) were minimised by the single transesterification step (rapid method). This rapid transesterification method appears to be an attractive alternative to FAME preparation from a wide variety of different fats for gas-liquid chromatographic analysis.     

Production of Human Milk Fat Replacement Rich of 1,3-dioleoyl-2-palmitoilglycerol From Enzymatic Interesterification Tripalmitin,Ethyl Oleate And Mixture of VCO,Soybean Oil And Fish Oil

Human Milk is naturally the only source of food for infant in their early life. It contains 2-6% lipid which provides about 50% of the total energy needed by the infant. Human milk fat (HMF) mainly as TAG with the specific fatty acid composition, palmitic acid (C16:0) (20-25%), which is primary located at sn-2 of glycerol bonds (70%) and oleic acid (C18:1), located at sn-1,3 (35%). HMF also provide fatty acids such as linoleic acid, linolenic acid, EPA, DHA and lauric acid that are very important for infant. The purposes of this research are to synthesize of 1,3-dioleoyl-2-palmitoilglycerol (OPO) and to determine the best composition of OPO, VCO, soybean oil and fish oil for HMFS production for infant formula. Interesterification of tripalmitin and ethyl oleate using immobilized lipase from Rhizomucor miehei (Lipozym RM IM) were used to synthesize of OPO. Interesterification product of mixed VCO, soybean oil and fish oil that are source of lauric acid, linoleic acid, α-linolenic, EPA and DHA, were formulated in mass ratio (58:20:20:2) and (70:18:10:2) for obtaining HMFS which have fatty acids composition similar or close to HMF. Composition of fatty acids from product were analyzed by GCMS. From this research, were obtained HMFS containing palmitic acid as much as 28.89% where 84.49% of that are located at sn-2 while sn-1,3 position are dominated by oleic acid as much as 55.11% from the total 38.7% and 70:18:10:2 w/w is the best composition of interesterification product, VCO, soybean oil and fish oil to obtain HMFS similar to HMF.     

Fatty Acid Composition of Tobacco Seed Oil and Synthesis of Alkyd Resin

The fatty acid composition of tobacco seed oil revealed that the oil is rich in unsaturated fatty acids, having linoleic acid （71.63%）, oleic acid （13.46%） and palmitic acid （8.72%） as the most abundant unsaturated and saturated fatty acids respectively. So the tobacco oil was characterized as semi-drying type on the basis of fatty acid composition. The synthesis of alkyd resin was carried out by alcoholysis or monoglyceride process using an alkali refined tobacco seed oil, pentaerythritol, cis-1,2,3,6-tetrahydrophthalic anhydride along with lithium hydroxide as catalyst. The alkyd resin so prepared was found to be bright and of low color with high gloss. The drying and hardness properties and adhesion of the tobacco seed oil derived alkyd resin were also found a bit superior to those of other alkyd resins of the same oil length. In addition, the water and acid resistance of the said alkyd was also found comparable to the other alkyds.     

不同方法对西藏林芝野生核桃油的提取及脂肪酸成分分析

分别采用超临界流体萃取法、索氏抽提法、超声波提取法从西藏林芝地区野生核桃中提取核桃油,并采用气相色谱-质谱法分析了核桃油的脂肪酸组成.结果表明,3种提取方法核桃油得率均在57%以上,核桃油主要脂肪酸含量为亚油酸62.54%、油酸18.93%、亚麻酸7.27%、棕榈酸5.36%、花生四烯酸4.11%、硬脂酸1.78%.其...     

模式识别法分析5种植物油脂

通过模式识别方法区分花生油、大豆油、米糠油、棕榈油和菜籽油。采用气相色谱法分析5种植物油脂的脂肪酸,用面积归一化法计算每个植物油脂样品的各脂肪酸相对含量。以每个植物油脂中9个脂肪酸的相对含量为变量,采用SPSS13.0软件的模式识别技术对119个植物油脂样品进行区分。由主成分分析图可知,花生油、大豆油、米糠油、棕榈油和菜籽油被清晰地分为5组。判别分析建立的判别方程能较好地实现样品的判别,自身验证和交互验证的准确率均为100%。另取每种植物油脂各5个样品(共25个)进行验证,识别准确率为100%。对调和有棕榈油的花生油进行主成分分析,在主成分分析图上,调和油的分布点在花生油分布区域与棕榈油分布区域之间。     

Quantitative determination of the fatty acid composition of human serum lipids by high-performance liquid chromatography

A high-performance liquid chromatographic method for the analysis of the fatty acid composition of human serum lipids with fluorescence detection was examined. Both free and total fatty acids extracted from serum were derivatized with 9-anthryldiazomethane and were analysed using methanol-water (94.7:5.3) as mobile phase. Twelve kinds of fatty acid were detected, both in the free and total fatty acids, and were well separated. Concentrations of individual fatty acids of serum lipids were estimated from an internal standard, heptadecanoic acid. The results correlated well with those from two other quantitative analyses. These results indicate that the high-performance liquid chromatographic analysis of fatty acids is a reliable method for determining individual fatty acids of human serum lipids. The compositions of free fatty acids and total fatty acids of serum lipids were analysed and compared in 27 normal subjects, 27 diabetics, and 20 angina pectoris patients by this method.     

ToF‐SIMS spectrometry to observe fatty acid profiles of breast tissues in broiler chicken subjected to varied vegetable oil diet

This study is aimed to observe changes in fatty acid profiles by time of flight secondary ion mass spectrometry (ToF‐SIMS) in breast muscle tissues of broilers. Four different groups were identified. The source of fat in group I was soy oil (rich in linoleic acid, ω‐6), group II received linseed oil (ω‐3), and the third group was fed a mixture of the two mentioned oils. Broilers in the control group were fed with beef tallow, used in mass commercial production. The results reveal that the use of vegetable oils in animal nutrition determines the lipid profile of fatty acids. ToF‐SIMS measurements showed that the lipid profile of muscle fibers and intramuscular fat reflect the composition of fats used as feed additives. In both structures, the ratio of ω‐6/ω‐3 fatty acids, which is most favorable for human health, was found in the groups in which a mixture of vegetable oils and a supplement of linseed oil were used.