Application of transmission FT-IR spectroscopy for the trans fat determination in the industrially processed edible oils

The amount of trans fatty acids (TFA) in fourteen industrially hydrogenated and deodorized oils was determined. To achieve better sensitivity 200 μm KCl cell was used in transmission Fourier transform infrared (FT-IR) spectroscopy. The results of transmission FT-IR spectroscopy were evaluated by gas chromatography (GC) with flame ionization detector (FID), and found to be comparable. All analyzed cooking oil samples had a lower trans content of 0.4–1.8%. Trans fatty acid contents of partially hydrogenated oil samples were relatively higher as comparable to those of the cooking oils. Among the samples examined, the highest level was found to be at 26.5% and 25.7% by the GC–FID and FT-IR spectroscopy, respectively. Due to harmful effects, high amounts of trans fatty acids in partially hydrogenated oils is an alarming issue for the consumer’s health and quality control authorities.     

Effects of Roasting Conditions on the Changes of Stable Carbon Isotope Ratios (δ13C) in Sesame Oil and Usefulness of δ13C to Differentiate Blended Sesame Oil from Corn Oil

Abstract: Differentiating blended sesame oils from authentic sesame oil (SO) is a critical step in protecting consumer rights. Stable carbon isotope ratios (δ¹³C), color, fluorescence intensity, and fatty acid profiles were analyzed in SO prepared from sesame seeds with different roasting conditions and in corn oil blended with SO. Sesame seeds were roasted at 175, 200, 225, or 250 °C for 15 or 30 min at each temperature. SO was mixed with corn oil at varying ratios. Roasting conditions ranging from175 to 250 °C at the 30 min time point did not result in significant changes in δ¹³C (P > 0.05). Values of δ¹³C in corn oil and SO from sesame seeds roasted at 250 °C for 15 min were −17.55 and −32.13 ‰, respectively. Fatty acid ratios, including (O + L)/(P × Ln) and (L × L)/O, where O, L, P, and Ln were oleic, linoleic, palmitic, and linolenic acids, respectively, showed good discriminating abilities among the SO blended with corn oil. Therefore, using different combinations of stable carbon isotope ratios and some fatty acid ratios can allow successful differentiation of authentic SO from SO blended with corn oil. Practical Application: Adulteration of sesame oil with less expensive oils such as corn oil or soybean oil to reduce cost is a common unethical practice in Korea. Due to the unique and strong flavor of sesame oils that may mask other weaker flavors, however, differentiating authentic sesame oils from blended oils is difficult. This study showed that the roasting process did not significantly affect the ratios of the stable carbon isotope (δ¹³C) in sesame oils. δ¹³C was confirmed to be a reliable parameter. Moreover, some fatty acid ratios were designed to discriminate between blended sesame oil with corn oil and authentic sesame oil.     

The effect of gamma irradiation on oleic acid in methyl oleate and food

The objective of this study was to investigate the effects of gamma irradiation on changes in oleic acid of methyl oleate as well as of beef and olive oil. The samples were irradiated at doses ranging from 0 to 60 kGy and the fatty acid composition was then analyzed by GC–FID and GC–MS. Gamma irradiation upon methyl oleate induced the formation of trans octadecenoic acid and stearic acid in a dose dependent fashion, while it decreased the amount of oleic acid. These findings indicate that the 9-cis structure is responsible for the formation of trans and saturated configurations. Additionally, the formation of stearic acid was facilitated by high temperature during the irradiation. Conversely, irradiation dose and temperature during irradiation had no significant effect (p > 0.05) on the amount of trans or saturated fatty acids in the beef and olive oil.     

Blends of olive oil and sunflower oil: Characterisation and olive oil quantification using fatty acid composition and chemometric tools

A method capable of recognising the percentage of olive oil in a blend is required to verify whether its labelling complies with the statements set out by the Commission Regulation (EC) No. 1019/2002. In this study an analytical methodology was developed in order to define blends of olive oil and sunflower oil, which contain 50% of olive oil, compared to blends with 40% and 60% of it, respectively. Methyl esters of fatty acids were analysed by GC–FID and processed through chemometric tools (PCA, TFA, SIMCA and PLS). A strong differentiation of blends according to the amount of olive oil contained and a quantification model with a standard error of prediction of 1.51% were obtained. As this issue represents a significant analytical challenge, variability associated with the fatty acid composition of olive oil was first studied.     

Fatty acid composition of seed oil of different Sorghum bicolor varieties

In order to find out new sources of premium quality edible oil in the country, seeds of ten varieties of Sorghum bicolor were initially analyzed for their total oil contents. The seed oil was later fractionated into eight fatty acids including two new saturated fatty acids. The oil contents were determined by Soxhlet method and compared with the results obtained by NMR analysis. The total oil contents in the seeds of sorghum ranged from 5.0 to 8.2 % (w/w), indicating non significant difference obtained by two different techniques. The results revealed that oleic acid (31.12–48.99%), Palmitoleic acid (0.43–0.56%), linoleic acids (27.59–50.73%), linolenic acid (1.71–3.89%), stearic acid (1.09–2.59%) and palmitic acid (11.73–20.18%) was present in the seed oil of different sorghum varieties when analyzed by GC–MS. It was observed that in most of the varieties polyunsaturated fatty acids (PUFA) were higher than monounsaturated fatty acids (MUFA). The two atypical SFAs, octanedioic (C8:0) and azelaic acid (C9:0) were found in some varieties. These results suggest that these S. bicolor varieties could be additional sources of edible oil due to presence of clinically important saturated and high concentration of unsaturated fatty acids. A large scale production of the seed oil after refining process can contribute towards alleviation of edible oil shortage in the country with increased use of premium quality oil.     

The influence of dietary hazelnut kernel oil on the performance and fatty acid composition of broilers

A total of 360 one‐day‐old broilers (Ross 308) were allocated to three treatment groups with four replicates each of 30 chicks to evaluate the effects of the dietary hazelnut kernel oil (HKO) inclusion on the performance and the composition of fatty acid of meat in broilers. Treatments were diets with (1) soybean oil (SO), (2) HKO, or (3) HKO + SO (in equal amount, HKSO) added to the basal diets. There were no significant differences in weight gain, feed per gain, dressing percentage, abdominal fat weight, and mortality among the different dietary oil sources. Dietary HKO decreased (P < 0.01) linoleic and linolenic acids contents and the ratio of SFA:MUFA (saturated fatty acids:unsaturated fatty acids) of breast meats in broiler, and increased oleic acid content compared to SO. The result indicates that meat from broiler chickens fed diets containing HKO, singly or combined with SO could be an important source of oleic acid for human diets. Copyright © 2007 Society of Chemical Industry     

NARP-HPLC/MS and silver cationization fingerprinting of triacylglycerols in wild and cultivar Tunisian peanut kernels

A simple strategy to identify triacylglycerols (TAGs) in wild and cultivar peanuts was performed using on line coupling of non-aqueous reversed phase chromatography-electrospray ionization–mass spectrometry (NARP-LC-ESI–MS) with silver nitrate (AgNO₃) as a post-column additive. The combination of the structural information given by MS with chromatographic retention laws led to the determination of the structure of TAGs in wild and cultivar peanut oil. In addition, by using the MS⁵ method, the regio-specificity of the TAGs was determined. It was also demonstrated that in Tunisian peanut oil, the saturates have a preference for the sn-1/sn-3 position for the arachidonic and behenic acids. In the wild variety fatty acids with odd numbers of carbons were found and more TAGs were identified in comparison to the cultivar peanut oil.     

气相色谱法测定脂肪酸含量判定山茶油纯度

利用气相色谱法,对山茶油掺入大豆油、菜籽油、玉米油和葵花籽油的掺伪油进行脂肪酸组成分析。结果表明:油酸、亚油酸和亚麻酸可作为鉴别山茶油中掺伪大豆油和菜籽油的特征脂肪酸,棕榈酸、油酸和亚油酸可作为鉴别山茶油中掺伪玉米油和葵花籽油的特征脂肪酸;回归预测模型相关系数(R^2)较高(> 0. 99),可分别检出掺伪量4%的大豆油和菜籽油,掺伪量8%的玉米油和葵花籽油,回收率在96. 56%~112. 88%之间。该方法灵敏度高,定量准确,可为掺伪山茶油纯度鉴别及调和山茶油配比的定量分析提供科学依据。     

Characterization of wax esters,free fatty alcohols and free fatty acids of crude wax from sunflower seed oil refineries

The sunflower seed wax (10–12%) from oil refineries was purified through two steps, namely, extraction using solvents and precipitation with chilled acetone. Fatty esters, free fatty alcohols and free fatty acids were separated by thin-layer chromatography (TLC). The fractions of fatty esters and free fatty alcohols were separated and identified by gas chromatography (GC) using a Dexil-300 column and OV-101 column, respectively, at temperatures from 150–290 °C and were further confirmed by Gas chromatography–mass spectrometry (GC–MS), using a capillary silica column SPB™-1 coated with polydimethyl siloxane. Among the long chain fatty esters (C₃₈–C₅₄), comprised of one unit of fatty alcohol and one unit of fatty acid through an ester linkage, the major esters were C₄₀–C_44, of which C₄₂ was predominant. These fatty esters, upon hydrolysis, followed by methylation and subsequent GC–MS analysis, showed the presence of C₁₆–C₃₀ fatty acids in the bound form, whereas methylation of native wax indicated the presence of C₁₈–C₃₀ fatty acids in the free form. Acetylation of hydrolysis product showed the presence of C₁₈–C₃₀ fatty alcohols in the bound form, where as acetylation of native wax indicated that the C₁₈–C₃₂ fatty alcohols were in the free form. n-Triacontanol (C₃₀), a plant growth regulator, was found in both free and bound forms.     

气相色谱全分析樱桃谷鸭肥肝脂肪酸

采用Folch 液回流提取樱桃谷鸭肥肝脂质,脂质经氢氧化钾- 三氟化硼法甲酯化后进行气相色谱分析,采用100:1 分流比进样,220～240℃线性程序升温操作,BPX70(60m × 0.25mm ID)石英毛细管柱分离,FID 检测。标准品对照结合线性程序升温等当碳长度(ECLT)值的方法定性了鸭肥肝中11种脂肪酸。面积归一法定量分析了基础日粮添加不同油脂和VE 对樱桃谷鸭肥肝中脂肪酸含量变化的影响。结果表明,基础日粮中按2% 水平分别添加山茶油、芝麻油以及大豆油后,肥肝不饱和脂肪酸含量均明显增加,与对照组比较均呈现极显著性差异(p ＜ 0.01),饱和脂肪酸含量明显下降,与对照组比较均呈现极显著性差异(p ＜ 0.01);基础日粮中按90IU/kg 水平添加VE 后,肥肝不饱和脂肪酸含量增加,与对照组比较差异显著(p ＜ 0.05),饱和脂肪酸含量下降,与对照组比较差异显著(p ＜ 0.05)。     

Antimicrobial properties and analytical profile of traditional Eruca sativa seed oil: Comparison with various aerial and root plant extracts

The present study investigates the antimicrobial activity of various solvent extracts of Eruca sativa (aerial and root) and seed oil against-antibiotic resistant Gram-negative (Escherichia coli, Pseudomoms aeruginosa and Shigella flexneri) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. Among the various preparations, seed oil was the most active, exhibiting a maximum zone inhibition of 97% for Gram-positive bacteria and of 74–97% for Gram-negative bacteria. The MIC of the seed oil was found to be 65–75 and 60–70 μg/ml for Gram-negative and Gram-positive bacteria, respectively. Analytical investigation on main volatile and non-volatile components was performed on seed oil. Among the formers allyl isothiocyanate (40 μg/g), 3-butenyl isothiocyanate (260 μg/g), 4-methylsulfinybutyl isothiocyanate (sulforaphane 743 μg/g), 2-phenylethyl isothiocyanate (159 μg/g) and bis(isothiocyanatobutyl)disulphide (∼5000 μg/g) were determined by head space/SPME/GC–MS analysis. Free fatty acids were 1.6% w/w of the oil and overall 25 fatty acids were identified. Erucic and oleic acids were the main fatty acids both in the free (7.8 and 2.1 mg/ml) and esterified forms (50.6% w/w and 14.9% w/w of total fatty acids). Unsaponifiable fraction was 1.8% w/w.     

超临界流体色谱和质谱联用在油脂分析中的应用

对油脂的分析,国内主要是采用气相色谱分离和火焰离子化检测器(FID)检测其中的脂肪酸组成,而对甘油酯的分离和检测报道较少,国外研究者利用色谱和质谱联用技术对甘油三酯的分离和检测做了大量的研究。超临界流体色谱是新近发展起来的分离技术,它保留了气相色谱和液相色谱的优点,但在一些方面更有优势。对超临界流体色谱的分离技术进行了介绍,并对超临界流体色谱和质谱联用(SFC-MS)技术在甘油三酯的分离和检测方面的应用和研究进展进行了综述。超临界流体色谱和质谱联用技术将是未来甘油三酯分离和检测的最佳方法。     

Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: Studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC–DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe²⁺ chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.     

基于脂肪酸指标的调和植物油品质评析

目的 对比基于脂肪酸指标的调和植物油与纯种植物油的品质。方法 利用气相色谱归一法测定2类植物油中8个样品的脂肪酸组成, 建立相应的指标, 对比分析其品质。结果 以脂肪酸种类为评定指标, 调和植物油1#、2#脂肪酸种类总数最多, 无反式脂肪酸检出, 含有二十二碳六烯酸组分; 以饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸比值为评定指标, 调和植物油1#中多不饱和脂肪酸与饱和脂肪酸比值为3.6, 比值高于除菜籽油和玉米油之外的纯种植物油; 以亚油酸与亚麻酸比值为评定指标, 调和植物油2#亚油酸与亚麻酸比值低于4:1, 符合中国膳食建议。结论 3种评价指标的建立可以快速、有针对性的对调和油的相关品质做出科学评析。     

Crude palm oil from interspecific hybrid Elaeis oleifera × Elaeis guineensis: Fatty acid regiodistribution and molecular species of glycerides

The composition and structure of triacylglycerols (TAGs) and partial glycerides of crude palm oil obtained from interspecific hybrid Elaeis oleifera × Elaeis guineensis, grown in Colombia, were fully characterised and compared to data obtained by analysing crude African palm oil. Hybridisation appears to substantially modify the biosynthesis of fatty acids (FAs) rather than their assembly in TAGs. In fact, total FAs analysis showed significant differences between these two types of oil, with hybrid palm oil having a higher percentage of oleic acid (54.6 ± 1.0 vs 41.4 ± 0.3), together with a lower saturated fatty acid content (33.5 ± 0.5 vs 47.3 ± 0.1), while the percentage of essential fatty acid, linoleic acid, does not undergo significant changes. Furthermore, 34 TAG types were identified, with no qualitative differences between African and E. guineensis × E. oleifera hybrid palm oil samples. Short and medium chain FAs (8:0, 10:0, 12:0, 14:0) were utilised, together, to build a restricted number of TAG molecular species. Oil samples from the E. guineensis × E. oleifera hybrid showed higher contents of monosaturated TAGs (47.5–51.0% vs 36.7–37.1%) and triunsaturated TAGs (15.5–15.6% vs 5.2–5.4%). The sn-2 position of TAGs in hybrid palm oil was shown to be predominantly esterified with oleic acid (64.7–66.0 mol% vs 55.1–58.2 mol% in African palm oil) with only 10–15% of total palmitic acid and 6–20% of stearic acid acylated in the secondary position. The total amount of diacylglycerols (DAGs) was in agreement with the values of free acidity; DAG types found were in agreement with the representativeness of different TAG species.     

Comparison of Yersinia pestis to other closely related Yersinia species using fatty acid profiles

Capillary gas chromatography with flame ionisation detection (GC–FID) was used to determine the cellular fatty acid (CFA) profiles of six Yersinia pestis strains. The profiles were then compared with the CFA profiles of other closely related Yersinia species including: Y. pseudotuberculosis, Y. enterocolitica, Y. intermedii, Y. kristensenii and Y. frederiksenii. For GC–FID analysis, whole cell fatty acid methyl esters (FAMEs) from cells cultured on brain–heart infusion (BHI) agar at 35 °C for 24 h were obtained by saponification, methylation and extraction into hexane/methyl tert-butyl ether. A data set for each Yersinia species was prepared using fatty acid profiles from five replicates prepared on different days. Major fatty acids of the 26 Yersinia strains evaluated in this study were straight-chain 12:0, 14:0, 15:0, 16:0 and unsaturated summed 16:1 ω7c/16:1 ω6c, 18:1 ω7c, and summed 14:0 3OH/16:1 iso, and 17:0 ω cyclo 7–8. The CFA profiles for Y. pestis and Y. pseudotuberculosis are similar, but there are several fatty acids, 16:1 ω5c, 16:0, 17:1 ω7c, 17:0 ω cyclo 7–8, 19:0 and summed 18:2 ω6c, 9c/18:0 ante, that differ significantly between these two species. Analysis of FAMEs from Yersinia strains grown on BHI agar by a rapid GC–FID method can provide a sensitive procedure for the identification of these organisms, and this analytical method provides a procedure for the differentiation of Y. pestis strains from closely related Yersinia species.     

西兰花种子油中甘油三酯和脂肪酸组成分析

分别使用超高效超临界流体色谱-四极杆飞行时间质谱联用仪和气相色谱-质谱联用仪鉴定西兰花种子油中甘油三酯(TAG)与脂肪酸组成.根据高分辨质谱一级质谱的母离子和二级质谱的碎片离子信息从西兰花种子油中鉴定出43种甘油三酯,采用峰面积归一化法对其在种子油中的相对含量进行表征.结果表明:鉴定的43种甘油三酯中含有13对同分异构...     

Essential oil composition of Salvia miltiorrhiza flower

Hydrodistillation of the flower of seven populations of Salvia miltiorrhiza Bge. collected in different locations in China afforded a pale yellowish oil in a yield of approximately 0.2%. A total of 82 compounds were identified across all the samples, accounting for 98–100% of the total compositions of each sample. Components were mainly monoterpenes, sesquiterpenes, fatty acids and alkanes. GC and GC–MS analysis indicated that the predominant components of the essential oils are β-caryophyllene (12.2–31.7%), β-caryophyllene oxide (1.4–11.6%), α-caryophyllene (4.8–10.6%), cadinadiene (7.4–29.3%), and hexadecanoic acid (3.9–18.8%).     

高分辨率反式脂肪酸测定方法的建立及市售食用油反式脂肪酸的测定

本文建立了高分辨率的反式脂肪酸测定方法,并考察了市售食用油的反式脂肪酸含量及其种类的情况。结果表明:采用高极性的色谱柱HP-88在优化后色谱条件下,可以实现4种亚油酸异构体、8种亚麻酸异构体、37种常见脂肪酸良好的色谱分离,而且反式脂肪酸与常见的顺式脂肪酸在同时检测条件下出峰时间不重叠,可以进行高分辨率的脂肪酸包括反式脂肪酸组成分析;市售主要品种的食用油都存在一定量的反式脂肪酸,其中调和油、花生油、大豆油含有2~3%的反式脂肪酸(反式亚麻酸含量在1.5~2%之间);玉米油和葵花籽油中反式亚油酸的含量在0.7~2%之间;稻米油的反式脂肪酸的含量最高,接近4%;橄榄油和山茶油的反式脂肪酸含量一般在0.5%以下;各油样的反式脂肪酸异构体的种类也存在区别。     

Rapid monitoring of heat-accelerated reactions in vegetable oils using direct analysis in real time ionization coupled with high resolution mass spectrometry

Transmission-mode direct analysis in real time ionization coupled with high resolution mass spectrometry (TM-DART–HRMS) was used to monitor chemical changes in various vegetable oils (olive, rapeseed, soybean and sunflower oil) during their thermally-induced oxidation. This novel instrumental approach enabled rapid fingerprinting of examined samples and detection of numerous sample components, such as triacylglycerols (TAGs), phytosterols, free fatty acids (FFA), and their respective oxidation products. Mass spectra obtained from DART were processed with the use of principal component analysis (PCA) in order to assess the compositional differences between heated and non-heated samples. Good correlation was observed between the normalized intensities of the pre-selected ion corresponding to mono-oxidized TAG and ‘classic’ criterion represented by the levels of TAG polymers determined by high performance-size exclusion chromatography with refractometric detection (HP-SEC–RID).