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.

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.

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.

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.

浅析气相色谱法在食用油中脂肪酸成分测定及其质量控制的应用

本文采用气相色谱法分析了食用油中脂肪酸组成,探讨了质量控制方法。通过对多种食用油样品进行实验可知,气相色谱法是一种高效、准确的分析方法,可以有效确定食用油中脂肪酸种类和含量。

棕榈油与常见食用油脂肪酸组分的比较分析

【目的】比较棕榈油与常见食用油脂肪酸组分的差异,为其作为优质食用油的品质改良提供参考依据。【方法】利用气相色谱检测6种市售食用油及20份新鲜油棕果提取的棕榈油,比较各油脂的脂肪酸组分差异,并分析新鲜油棕果提取的棕榈油脂肪酸组分间的相关性。【结果】6种食用油的油酸含量均较高,最高的是油茶油,油酸含量高达74.34%,最低的是葵花籽油,为15.25%;亚油酸含量则以葵花籽油最高(60.92%),油茶油最低(7.08%);棕榈油中棕榈酸占脂肪酸总量的40.96%,其次为油酸,所占比例为35.31%;各食用油中的月桂酸、肉豆蔻酸和硬脂酸含量均较低。芝麻油、油茶油、菜籽油、花生油和葵花籽油中的不饱和脂肪酸含量均较高,在76.00%以上。对20份新鲜的油棕果进行脂肪酸组分分析,发现部分油榈种质油酸含量较高,可达53.48%,亚油酸含量最高为16.64%;棕榈酸与油酸呈较强的负相关,相关系数为-0.58。【结论】棕榈油中脂肪酸组分与其他常见食用油的脂肪酸组分含量差异明显,其棕榈酸含量较高,油脂饱和度也较高,但棕榈酸与油酸呈负相关,可在育种工作中培育高油酸、低棕榈酸的油榈品种,使其成为优质的食用油源。

厦门及周边地区产10种食用菌的脂类研究

对厦门及周边地区产的黑木耳、鲍鱼菇、平菇、香菇、草菇、茶树菇、鸡腿菇、金针菇、蘑菇和姬松茸(子实体和菌丝体)的10种食用菌样品中的脂肪进行了测定,并采用气相色谱方法分析了样品中的脂肪酸组成及其含量.测定结果表明:这些食用菌的粗脂肪含量在1%～5%之间,其中姬松茸子实体最高(约5.4%),最低者为黑木耳(约0.7%).脂类中共有10种脂肪酸组成得到了确认,但在含量及饱和脂肪酸与不饱和脂肪酸比值上存在着较大的差别.其中又以棕榈酸、硬脂酸、油酸和亚油酸等为主要脂肪酸,其余的则明显较少.这些为从不同角度探讨对上述食用菌的利用提供了实验依据.

常用动、植物食用油中脂肪酸组成的分析

以氢氧化钾/甲醇碱催化法对食用油样品进行甲酯化衍生化预处理,采用气相色谱-质谱联用技术,对采自西安、咸阳市的16种食用植物油和4种动物油(猪油、牛油、羊油和鸡油)中的脂肪酸组成进行测定,并对其所含各类脂肪酸的比例关系进行详细地分析,以确定不同类型食用油的营养特征。结果显示,各类食用油所含的主要脂肪酸成分是棕榈酸、硬脂酸、油酸、11-十八碳烯酸、亚油酸、亚麻酸、花生单烯酸以及芥酸等;不同类型的食用油脂中,饱和、单不饱和、多不饱和脂肪酸之比值差异极大,而且多不饱和脂肪酸中n-6脂肪酸与n-3脂肪酸之比值差别也很大。

我国市售食用植物油中脂肪酸氯丙醇酯的污染调查

食用油脂中的脂肪酸氯丙醇酯(简称氯丙酯)是近年来国际关注的新的食品污染物,本研究调查了我国市售食用植物油中氯丙酯的污染情况。在全国多个大型连锁超市采集大豆油、茶籽油、花生油等11种共143份食用植物油。样品经碱水解后,以硅藻土基质分散固相萃取法净化,样液经衍生后采用气相色谱/质谱联用法(GC/MS)检测,以稳定性同位素内标法对3-氯-1,2-丙二醇酯(3-MCPD酯)和2-氯-1,3-丙二醇酯(2-MCPD酯)进行定量。调查发现,11类食用植物油中3-MCPD酯和2-MCPD酯的检出率分别为74.8%和49.7%,含量分别在0.064(最低检出限,LOD)～5.96 mg/kg和0.072(LOD)～3.43 mg/kg(分别以游离形式的3-MCPD和2-MCPD计)之间;茶籽油和芝麻油污染问题较为突出,其3-MCPD酯含量的中位数分别为1.63、0.60 mg/kg。样品中2-MCPD酯与3-MCPD酯的含量之间存在线性相关,相关系数为0.899。

企鹅珍珠贝和马氏珠母贝软体部脂肪酸组成

对企鹅珍珠贝和马氏珠母贝软体部脂肪进行了提取和测定。结果表明,企鹅珍珠贝和马氏珠母贝软体部脂肪含量分别为8.3%和9.6%。企鹅珍珠贝脂肪酸中DHA+EPA的总含量为39.71%,比马氏珠母贝脂肪酸中DHA+EPA的总含量(30.86%)高。2种珍珠贝软体部脂肪酸均具有重要的开发利用价值。

湖南地区5种常见食用菌的营养成分分析

目的对湖南地区常见的5种食用菌中所含基本营养成分、矿物质元素、氨基酸及脂肪酸的含量进行检测和分析。方法依据国家标准斱法,采用气相色谱-质谱联用仪、电感耦合等离子体质谱仪、全自动氨基酸分析仪等进行成分分析。结果 5种食用菌在营养成分上存在一定的差异,其水分含量为86.0～92.8 g/100g,蛋白质含量为2.3～3.8g/100g,脂肪含量为0.2～0.5g/100g,膳食纤维含量为2.1～4.1g/100g,灰分含量为0.6～1.0 g/100 g, 5种食用菌均富含钾和磷,香菇富含铁、锌、锰,双孢菇富含钙、铁、铜。杏鲍菇的必需氨基酸与非必需氨基酸的比值高于其他4种食用菌。5种食用菌中脂肪酸以亚油酸为主,其中釐针菇同时含有亚油酸和α-亚麻酸2种必需脂肪酸。结论 5种食用菌可视为高蛋白低脂肪、高钾低钠食物,在营养价值斱面各具优势,为人们更合理科学的使用食用菌提供参考依据。

美国引进向日葵种子含油量和脂肪酸组成比较分析

以天津检验检疫局引进的24种美国向日葵种子为原料,其中食用型和油用型种子各12种,测定了24种向日葵种子的含油量,并用气相色谱法测定了向日葵种子油脂肪酸组成及相对含量。结果表明：24种向日葵种子含油量介于33.26%~47.24%之间;向日葵种子油脂肪酸组成为棕榈酸、硬脂酸、油酸和亚油酸,油酸和亚油酸的相对含量较高,油酸相对含量介于16.07%~91.30%之间,亚油酸相对含量介于2.33%~71.45%之间,不饱和脂肪酸相对含量介于87.43%~93.63%之间;分析发现,油用型向日葵种子油的油酸含量相对较高,食用型向日葵种子油的亚油酸含量相对较高。

快速气相色谱法测定食用油中的未衍生化长链脂肪酸

建立了利用短的微径色谱柱直接测定食用油中未衍生化长链脂肪酸的快速气相色谱方法。C12-C22脂肪酸在2min之内实现基线分离,定量标准曲线的相关系数大于0.988,最低检测限(S/N=3)为2.80-9.60mg/L,回收率为74.5%-86.5%。该方法快速、简便、准确,分析通量大,已成功地用于香油、色拉油及调和油等3种食用油中长链脂肪酸含量的测定。

超高效合相色谱-质谱法快速分析食用植物油中常见脂肪酸

建立了超高效合相色谱.质谱（ UPC2.MS）快速分析6种食用植物油（玉米油、葵花籽油、大豆油、茶油、菜籽油、花生油）中棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸等5种常见脂肪酸的方法，并比较了这6种食用油中上述5种脂肪酸的含量差异。采用皂化反应对植物油进行前处理，以 ACQUITY UPC2 BEH 2.EP 色谱柱（100 mm×2.1 mm，1.7μm）为分析柱，以超临界CO2.甲醇／乙腈（1∶1， v／v）为流动相进行梯度洗脱，流速为0.8 mL／min。在电喷雾负离子模式下进行检测，外标法定量。结果表明：5种脂肪酸标准物质在0.5～100 mg／L范围内呈现良好的线性关系，相关系数为0.9985～0.9998，定量限（ S／N≥10）为0.15～0.50 mg／L；在3个添加水平下，样品的加标回收率为89.61％～108.50％；方法重复性的相对标准偏差（ RSD）为0.69％～3.01％。该方法简单、快速、分离效果好，无需对脂肪酸样品进行衍生化，已成功地用于玉米油、葵花籽油、橄榄油、茶油、大豆油和花生油等6种食用油中常见脂肪酸含量的测定。

8种食用菌游离氨基酸的组成及含量比较

【目的】研究8种食用菌游离氨基酸的组成、含量及呈味效果。【方法】采用高效液相色谱-蒸发光散射检测法(HPLC-ELSD),分别对香菇、白灵菇、海鲜菇、平菇、双孢菇、秀珍菇、杏鲍菇和金针菇8种食用菌的游离氨基酸组成及含量进行测定。【结果】白灵菇和金针菇的游离氨基酸种类最多,均有10种,除双孢菇不含有游离必需氨基酸外,其余7种食用菌均含有游离必需氨基酸。海鲜菇的游离必需氨基酸含量最高,为3.444mg/g;游离呈味氨基酸则以白灵菇含量最高,为45.680mg/g;游离限制氨基酸含量最高的是平菇,达0.413mg/g。对8种食用菌呈味效果贡献最大的是甘氨酸(Gly),其含量占8种食用菌游离氨基酸总量的19.56%~52.97%,味道强度值(Taste active value,TAV)为1.10~5.08。8种食用菌中,味道比较鲜的食用菌如香菇、白灵菇、海鲜菇、双孢菇都含有天冬氨酸(Asp),含量为2.155~45.310mg/g。【结论】从游离氨基酸来看,海鲜菇和双孢菇的食用风味最佳,平菇和金针菇营养价值最好。

微波辅助衍生化GC-MS法测定食用油中的脂肪酸

利用微波技术，研究了用ＫＯＨ－ 甲醇、Ｈ２ＳＯ４－甲醇－甲苯、ＨＣｌ－甲醇等不同体系对食用油中的脂肪酸进行衍生化，系统地比较了它们的优劣势，以及适合的分析对象。在１ ｍ ｉｎ 内完成衍生化反应，选用正庚烷代替传统方法的苯＋ 石油醚作为脂肪酸甲酯的提取剂，与传统消解及衍生化方法相比，具有节省溶剂、省时、易于操作等特点。

部分食品煎炸用油的反式脂肪酸比较

为探究不同品种食用油和煎炸食品对反式脂肪酸形成的影响,本文使用5种食用油(葵花油、大豆油、菜籽油、棕榈油、花生油),在一定温度下炸制14批次油条,又依次使用大豆油炸制豆腐、油条和鸡腿,对2种情况下产生的煎炸油进行气相色谱分析,比较反式脂肪酸含量。结果表明:炸油条过程中,食用油中反式脂肪酸的含量均随着煎炸时间的延长而增加,葵花油中反式亚油酸总含量最多(约12 mg/g),花生油中反式油酸含量最低(约0.6 mg/g),在煎炸过程中,大豆油中反式脂肪酸的含量无显著变化,保持在3.5 mg/g左右。比较可知,不同种类食用油在加热过程中产生的反式脂肪酸含量有较大差异,而使用大豆油分别炸制豆腐、油条和鸡腿时,煎炸油中的反式脂肪酸无显著差异,说明油炸过程中的反式脂肪酸主要来源于食用油中不饱和脂肪酸的氧化裂解和异构化,与煎炸食品关系不大。从反式脂肪酸的生成量来看,烹饪过程中长时间煎炸建议使用大豆油,而不适宜使用葵花油。

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。