Assessment of Trans Fatty Acid Content in Widely Consumed Snacks by Gas Chromatography in a Developing Country

Trans fatty acids have adverse effects on health, so knowledge of their contents in foods would enable people to make informed food choices. TFA levels when not available in food composition tables make it difficult to estimate dietary intake. With the aim to analyze and identify the actual amount of trans fatty acid present in selected Indian fast food items, triplicate samples of six commonly consumed snacks as well as the oil used for preparing the same were collected from three different places. The separation of fatty acid was done using gas chromatography. Trans fatty acid isomers of oleic acid, linoleic acid and linolenic acid were identified in all food items. The predominant trans fatty acid present in all the food items was elaidic acid (18:1t9). The total trans fatty acids in different food items ranged from almost negligible to as high as 14.58 g/100g food. Different amount of TFA was found in same food category sourced from different outlets which is a challenge in making regulations aimed at TFA reduction so as to decrease health risk.

Fatty Acids and Associated Cardiovascular Risk

Introduction: A fatty acid (FA) is a carboxylic acid with a long aliphatic chain, which is either saturated or unsaturated. Recently, the role of FA and particularly omega-3 and -6 has emerged as cardiovascular risk factor in the literature. The aim of our study was to establish reference values for these FA and to compare them with data obtained in a population of acute myocardial infarction (AMI) patients. Materials and methods: Hundred thirty five healthy subjects (59.38 ± 27.12 yo, 75 men) were selected as reference population. We also evaluated FA in thirty three patients (55 ± 9 yo, 23 men) admitted in the Emergency Department of our Institution for AMI. The fasting whole blood was drawn in vacutainer containing EDTA. Before analysis, samples were washed and transmethylated. We performed the quantification of different FA by gas chromatography associated with flame ionization detector (GCFID). Results: We obtained results in control healthy patients to be used as reference values. In the AMI group, levels of omega-6 were significantly higher (p 0.05) for C18:2n6 and C18:3n6 than the reference population and omega-3 values were significantly lower (p 0.01) compared to reference value for C22:6n3. The omega-3 index was lower and the ratio omega-6/omega-3 was higher in AMI group compared to reference values. Conclusions: We have established reference value for FA and have compared these values with the results obtained in AMI population. FA determination is a new tool we are able to use and to process in our laboratory which can help the clinician to screen patients with the highest cardiovascular risks because of the implication of FA in the etiopathogeny of atherosclerosis.

Composition Analysis on Intermuscular Fatty Acid of Qinghai Datong Yak

[ Objective] The study aimed to provide a theoretical basis for rational utilization of Datong yak resource. [ Method] By qualitative and quantitative determination with gas chromatograph, the composition and content of intermuscular fatty acid of Datong yak were compared with those of Datong yellow cattle. [ Result] Comparing with Datong yellow cattle, Datong yak had lower saturated fatty acid （SFA） content and higher polyunsaturated fatty acid （PUFA） content at extremely significant level （P 〈0.01 ）, while the difference of monounsaturated fatty acid （MUFA） contents between them was not significant （P〉0.05）. The PUFA/SFA and n-6/n-3 PUFA of Datong yak were in accordance with the recommended proportions. [ Conclusion] The intermuscular fatty acid composition of Datong yak is superior to that of local yellow cattle, which indicates that Datong yak meat has high nutritive value and wide development prospect.

Development of a Derivatization-free GC-FID Method for Evaluation of Free Fatty Acid Levels in Plasma of Diabetic Nephropathy Patients

Metabolism of free fatty acids（FFAs） is related to several important physiological events and therefore their quantitaion in biological samples arouses extensive interest and efforts.Existing gas chromatography with flame ionization detector（GC-FID） methods for the analysis of FFAs normally require derivatization of them in order to lower boiling points.But this extra procedure tends to induce additional error and it is laborious and time-consuming.A derivatization-free method was therefore established in the present investigation to determine FFAs in human plasma by capillary（GC-FID）.After extraction of FFAs from plasma,a highly polar FFAP（free fatty acid in plasma） column was employed to directly quantitate FFAs concentration,free from derivatization reaction.All sample pretreatments were carried out at room temperature,improving recovery of short-chain FFAs.Heptadecanoic acid（C17：0） was employed as internal standard,and the proposed method was validated for recovery,precision,sensitivity,stabi-lity,and linearity.Validation data show that it is suitable for clinical study that has been applied to the evaluation of FFAs levels in plasma of diabetic nephropathy（DN） patients during the course of treatment.Forty-seven patients diagnosed with DN were admitted to the double-blind experiment.Control group（n=17） underwent solely basic treatment and the patients did not show significant change in FFAs concentration during six months of treatment.Experiment group（n=30） was supplied with traditional Chinese medicine besides basic treatment.After six months of medication,their plasma concentration of palmitic acid（C16：0）,stearic acid（C18：0） and oleic acid（C18：1n-9） decreased while linolenic acid（C18：3n-3） increased significantly（P〈0.05）.These four compounds could be served as biomar-kers in the evaluation of drug efficacy,and their quantitation in plasma may provide additional information for disease progression in DN patients.

Trans Fatty Acid Content of Iranian Edible Oils

Clinical and epidemiologic studies showed that among dietary factors the type of fatty acids (FAs) in the diet plays an important role in determining risk of chronic disease. The aim of our study was to determine the levels of Trans FA (TFA) in edible oil samples consumed in Tehran, Iran analyzed by gas chromatograph (GC). The mean of total TFA was 0.45% ranging from (0.11% - 1.61%) for liquid frying oils and 2.92% ranging from (0.46% - 5.40%) for solid oils. The major TFA observed in these two groups was elaidic acid in solid oils. The highest content of total saturated fatty acid (SFA) was detected in solid oils with average of 32.07 and palmitic acid was the major SFA in these four groups. Linoleic and linolenic acid are the most important poly unsaturated fatty acid (PUFA). The variance in the percentage of TFA in the edible oils probably resulted from differences in the type of oils, quality, heating, processing technique and storage condition of the edible oils. The results indicated that, edible oils contain considerable proportions of trans fatty acids. Therefore, it is important to assess the content of TFA in edible oils in Iran.

Extraction of Fat and Fatty Acid Composition from Slaughterhouse Waste by Evaluating Conventional Analytical Methods

To attain maximum recovery of useful compounds from slaughterhouse waste (Suet, Tongue, Pancreas) of selected ruminant (cow, goat, lamb, and bull), the fat extraction efficiency of popular methods was compared along with fatty acid (FAs) composition. Four selected methods including Soxhlet (SOX), acid hydrolysis, Bligh & dyer (B&D), and Folch (FOL) were assessed. After methylation, extracted lipids were analyzed by Gas chromatography for FA composition. Data indicated that all selected methods were significantly (p < 0.05) different from each other, particularly higher differences were noticed for low lipid-containing products (Tongue, Pancreas) as well as their respective FA Composition. Based on Analysis of Variance and Principal component analysis, the effective method for lipid and FA Composition analysis was the FOL method. The Soxhlet method was only effective for samples with high-fat content i.e., suet, while the B&D method gave comparatively low lipid content in analyzed samples. Hence based on the results, excellent fat and fatty acid extraction was achieved with the FOL method.

若干需氧芽孢杆菌芽孢脂肪酸成分分析

51株需氧芽孢杆菌纯化后的芽孢培养物经处理抽提全细胞脂肪酸甲酯 ,用于气相色谱分析 ,同时以相应的繁殖体作为对照。芽孢脂肪酸成分的重现性实验发现 ,芽孢的脂肪酸成分比较稳定。将脂肪酸百分含量编制成原始数据矩阵 ,以 Statistica5.0统计软件进行聚类分析 ,得到两张分别基于芽孢脂肪酸成分和繁殖体脂肪酸成分的实验菌株树状聚类图。通过对比这两张图可以得出一些有意义的结论 ,同时也说明芽孢脂肪酸分析可望成为需氧芽孢杆菌化学分类的新手段。

超声提取-毛细管气相色谱法全分析倒刺鲃组织中的脂肪酸

采用Folch液超声提取倒刺鲃组织样品中的脂肪,脂质提取液经氢氧化钾-三氟化硼甲酯化后进行气相色谱分析。采用100∶1分流比进样,220-240℃程序升温操作,BPX70石英毛细管柱（60m×0.25mm）分离,火焰离子化检测器检测。利用标准品对照并结合线性程序升温等当碳链长（ECL^T）值对照的方法对脂肪酸组分包括存在双键异位的不饱和脂肪酸进行定性。测定了野生和箱养倒刺鲃肌肉与脂肪中17种脂肪酸的含量。结果表明箱养倒刺鲃的脂肪酸营养结构与野生倒刺鲃无明显区别,不饱和脂肪酸占大多数,单不饱和脂肪酸含量高于多不饱和脂肪酸,n-6族不饱和脂肪酸含量明显高于n-3族。

GC-MS技术在鉴定食源性致病菌研究中的应用

通过有机溶剂提取、TLC分离及GC-MS对食源性致病菌中常见的4个属9种19株病原菌的全细胞脂肪酸组分进行了分析。结果表明:沙门氏菌属、埃希氏菌属、弧菌属和志贺氏菌属全细胞脂肪酸组分都含有十四烷酸、十六烷酸和十八碳烯酸,这三种脂肪酸占总脂肪酸含量的90%左右,含量最高的是十六烷酸,含量在40%以上,其次是十八碳烯酸,含量在30%左右。脂肪酸组成在属间差异显著。大肠杆菌O157不含有十三烷酸和十五烷酸,副溶血弧菌不含有十二烷酸和十三烷酸,志贺氏菌含有特异性的环戊烷十三烷酸。这些特征可作为各个属分类鉴定的依据。模式菌株和地方菌株在含有双键的脂肪酸上,双键的位置有一定的差异,因此通过这些差异可以鉴定模式菌株与地方菌株。

产EPA南极细菌的筛选及其脂肪酸成分分析

目的从南极细菌中筛选高产EPA(二十碳五烯酸)或DHA(二十二碳六烯酸)的细菌,并对其脂肪酸的成分和含量进行分析。方法从南极采集的海冰和土壤中分离得到200株细菌,利用改良的一步反应法,通过气相色谱(GC)初筛,得到8株EPA或DHA产量较高的细菌。对其中一株EPA产量最高菌株(NJ136)的总脂含量采用索氏抽提法测定,各脂肪酸成分和含量采用气相色谱-质谱(GC-MS)分析测定。结果与结论菌株NJ136的EPA相对含量为6.66%,不饱和脂肪酸的相对含量为51.92%,干菌总脂含量是7.94%,EPA含量达到5.3 mg.g-1,不饱和脂肪酸含量达到41.2 mg.g-1。

影响肠道细菌发酵因素的体外研究

目的 : 体外研究不同因素对肠道细菌发酵产生短链脂肪酸的影响 ,为膳食改善肠道功能提供依据。方法 : 在体外进行细菌培养 ,用稳定性同位素标记的葡萄糖作底物 ,用气相色谱 -同位素比值质谱法测定短链脂肪酸。用荧光染色法计数细菌数量。结果 : 结果显示细菌数量高 ,短链脂肪酸产生多 ,p H=7时产生的短链脂肪酸最多 ;添加酪蛋白可增加短链脂肪酸的产生及细菌数量 ;13 C-葡萄糖不但被发酵产生短链脂肪酸 ,而且也被用于细菌增殖。结论 : 人体肠道细菌发酵产生短链脂肪酸的能力受细菌数量、p H及底物不同的影响 ,此为通过选择不同膳食 (含益生原的食物如小麦、洋葱、香蕉、大蒜、韭菜、土豆等 )以调节结肠的功能提供了依据。

人血清中脂肪酸的GC-MS分析

A method for determination of fatty acids(FA) compositions in human serum by gas chromatography time-of flight mass spectrometry(GC-TOF MS) method was established.The FA in serum were directly transformed into the fatty acid methyl esters by 2.5% H2SO4-methanol.Heptadecanoic acid methyl esters were used as internal standard.The detection and separation of all the FA were performed within 33 min.The established method has the characteristic of simple operation,rapid analysis,high accuracy,large amount of information and safety.So it is suitable for the scientific research to the disease correlating FA.

用气相色谱-同位素比值质谱法测定体外肠道细菌发酵产生的短链脂肪酸

目的 :了解肠道细菌发酵产生短链脂肪酸的情况 ,为乳糖不耐症状的发生提供依据。方法 :在体外进行细菌培养 ,用稳定性同位素标记的葡萄糖作底物 ,用气相色谱 -同位素比值质谱法测定短链脂肪酸。结果 :细菌纯培养显示不同菌株产生的短链脂肪酸不同。人体粪便培养表明不同人体产生的短链脂肪酸的种类相同 ,而各种类数量不同。结论 :所测定的人体肠道发酵产生短链脂肪酸的能力不同 。

环境因子对好氧不产氧光合细菌脂肪酸组成的影响

对赤杆菌属(Erythrobacter)、柠檬酸微菌属(Citromicrobium)和玫瑰杆菌(Roseobacter)分支的9株好氧不产氧光合细菌(AAPB)的脂肪酸组成进行分析,并以10株非AAPB菌为参照,从脂肪酸角度考察光照、温度、营养等重要环境因子对AAPB的影响。结果显示,AAPB的脂肪酸以C18:1 w7c为主,该成分在Roseobacter分支中含量最高,不同种脂肪酸对环境因子的响应不同,低温和寡营养条件主要作用于不饱和脂肪酸(UFA);二羟基脂肪酸在寡营养和光照双重作用下有较明显的升高。此外,结合非AAPB的比较也为AAPB脂肪酸研究提供了新的视角,如温度实验显示,由于不饱和脂肪酸的比例较高,AAPB可能在寒冷海域有更好的竞争优势,而从饥饿培养试验来看,AAPB的异养能力似乎比非AAPB更弱。

A comparison of methods used to determine the oleic/linoleic acid ratio in cultivated peanut (Arachis hypogaea L.)

There is an increasing demand in the peanut industry for high oleic peanuts and also for the incorporation of the high oleate trait into newly released varieties. Early generation screening of breeding lines for high oleic acid content greatly increases the efficiency of developing new peanut varieties. The objective of this study was to compare the accuracy of methods used to classify individual peanut seed as high oleic or not high oleic. Results from capillary electrophoresis (CE), two variations of near-infrared reflectance spectroscopy (NIRS), and real-time polymerase chain reaction (RT-PCR) genotyping, were compared with the traditionally accepted reference standard results from gas chromatography (GC). Three hundred and seventy-four (374) seeds, spanning twenty-three (23) genotypes and all four peanut market-types (runner, Spanish, Valencia and Virginia), were individually tested by each method. Percent accuracy levels for rating individual seed as high oleic (H) ranged from 97.4% (NIRS) to 99.5% (CE). All of the methods examined in this study carry only a minor risk for miss-classification (loss of material) and are suitable for use by peanut breeding programs in early generation breeding line screening.

Principal Component Analysis （PCA） on Multivariate Data of Lard Analysis in Cooking Oil

Discrimination of fatty acids （FAs） of lard in used cooking oil is important in halal determination. The aim of this study was to find the information related to the changes FAs of lard when frying in cooking oil. Quantitative analysis of FAs composition extracted from a series of experiments which involving frying cooking oil spiked with lard at three different parameters; concentration of spiked lard, heating temperatures and period of frying. The samples were analyzed using Gas Chromatography （GC） and Principal Components Analysis （PCA） technique. Multivariate data from chromatograms of FAs were standardized and computed using Unscrambler X10 into covariance matrix and eigenvectors correspond to Principal Components （PCs）. Results have shown that the first and second PCs contribute to the FAs mapping which can be visualized by scores and loading plots to discriminate FAs of lard in used cooking oil

Supplemental Feeding of Laying Hens with Wood Vinegar to Decrease the Ratio of n-6 to n-3 Fatty Acids in Eggs

A balanced ratio of fatty acids n-6 to n-3 in chicken eggs is important for health and to help prevent and manage obesity and other diseases.Traditionally,fish oil or flax seed has been utilized as feed additives to decrease the ratio of n-6 to n-3(n-6:n-3)fatty acids in eggs.The hull of spina date seed(HSDS)is a common agricultural waste product in China,from which wood vinegar(HSDSWV)may be derived.This study evaluated HSDSWV as a sup-plement in hen feeds to improve the quality of eggs and decrease the ratio of fatty acids n-6:n-3.HSDSWV was obtained via carbonization,and refined.Six concentrations(nil to 0.5%)of HSDSWV were prepared and fed to 6 hen groups,respectively,for 50 d.The fatty acids of the hen’s egg yolks were analyzed by gas chromatography/electron ionization-mass spectrometry(GC/EI-MS)in the selected ion monitoring(SIM)mode.The 0.2%HSDSWV resulted in the best egg yolk quality,with a lower percentage of linoleic acid(C18:2n6)and higher percentages of cis-5,8,11,14,17-eicosapentaenoic acid(C20:5n3)and cis-4,7,10,13,16,19-docosahexaenoic acid(C22:6n3),and thus a lower n-6:n-3 ratio compared with the other HSDSWV concentrations.In addition,the eggs contained higher levels of yolk fat and egg yolk than the controls did.In conclusion,to modify the fatty acid composition of hens’eggs and obtain a balanced ratio of n-6:n-3,0.2%HSDSWV may be considered suitable as a dietary supplement in hens’feed.

Analysis of Brucella cellular fatty acids

To acquire data of Brucella cellular fatty acids(CFAs)and probe into the possibility of utilizing CFAs information in typing Brucella,19 reference strains were subjected to CFAs study.After all strains were inoculated on Brucella Agar plates,the cells were harvested,saponificated,methylated and extracted to provide fatty acid methylesters for gas chromatography(GC)analysis.Based on the CFAs data matrix,a dendrogram of 19 reference strains was generated by SPSS11.5 software package.The results showed that 19 reference strains were divided intofive clusters:cluster 1 included B.suis(bv.1,2,3,5)and B.ovis;cluster 2 included B.abortus(bv.3,4,5,6)and B.melitensis(bv.1,2,3);cluster 3 included B.abortus(bv.1,2,7,9)and B.neotomae;cluster 4 was B.suis(bv.4);and cluster 5 was B.canis.Typing Brucella by GC analysis of CFAs is a good method to reflect drug resistance of Brucella,and the classification is beneficial for clinical therapy.It also provides a new result of typing and demonstrates that the traditional classification is not completely reasonable.CFAs analysis may identify B.suis(bv.4)and B.canis.

Determining short chain fatty acids in sewage sludge hydrolysate: A comparison of three analytical methods and investigation of sample storage effects

In anaerobic digestion, the production of short-chain fatty acids （SCFAs） can be beneficial or harmful to the overall process, depending on the concentration of accumulated acids. Therefore, the accurate determination of the SCFA concentration in both fresh and stored sludge hydrolysates is important. To select a suitable method for monitoring SCFAs during the anaerobic digestion of sewage sludge, the accuracy of three available analytical methods, including 5 pH point acid titration （TITRA5）, gas chromatography （GC）, and spectrophotometry, were compared in the present study. The results revealed that TITRA5 and GC displayed better agreement in the achieved measurements and higher precision and accuracy than the spectrophotometric assay, as supported by the application of different statistical models. TITRA5 excelled in titrating unfiltered hydrolysate while simultaneously measuring the alkalinity, whereas the GC method provided detailed information on the contribution of different fatty acids to the total acidity. In contrast, the spectrophotometric assay suffered from many forms of interference, depending on the sample＇s matrix. SCFA production followed the pattern of enzymatic reactions and fitted the Michaelis-Menten model. In addition to promoting TITRA5 as an accurate and robust analytical tool for routine SCFA analyses, this comparative study also demonstrated the possibility of storing hydrolysate samples at different temperatures and durations without altering the SCFA measurements.

Production of conjugated linoleic acids by Lactobacillus plantarum strains isolated from naturally fermented Chinese pickles

Naturally fermented pickles harbour many lactic acid bacteria （LAB）. Forty-three LAB strains with conjugated linoleic acid （CLA）-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, Ip15 identified as Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability （26.1% conversion） at 48 h in de Man Rogosa Sharpe （MRS） broth in the presence of 100 IJg/ml of linoleic acid （LA）. Compared to other strains, L. plantarum strain Ip15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 μg/ml. This strain converted about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA （9-CLA） and trans-lO, cis-12 CLA （10-CLA）], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by Ip15 remained stable between 100 to 600μg/ml LA levels in the medium, it dropped sharply at 1000 μg/ml. Taken together, the Ip15 strain displayed relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing the CLA content in food-sources like pickles.