油脂脂肪酸指纹库构建及在食用油脂地沟油类别鉴别中应用

目的建立一种测定食用油脂、地沟油中各脂肪酸含量的毛细管气相色谱法,构建脂肪酸指纹库用于食用油脂类别辨析、地沟油鉴别。方法选择强极性毛细管柱,柱程序升温,载气高纯氮,进样口温度260℃,不分流/分流进样模式,进样1μL,氢火焰离子化检测器(FID)检测,面积归一法定量;采集色谱图,Excel 2007表汇总、构建各类油脂脂肪酸指纹库、对各类油脂特征性、特异性解析,辨析油脂类别。结果 C18:3、C20:5、C22:6 3种脂肪酸甲酯的质量浓度均在(0.05~20.0)mg/m L,与峰面积呈良好线性关系(r0.999);方法质量检出限为1 ng,3水平平均回收率为95.3%~98.5%,相对标准偏差(RSD)均5%,新法测定9类(动植物油脂、食用调和油、地沟油)119份油脂中组分脂肪酸含量;完成脂肪酸构成色谱图采集、构建指纹库;解析脂肪酸组成指纹库各类油脂脂肪酸组成含量差异特征明显,饱和脂肪酸、肉豆酸(C14:0)等特征差异明显,据此进行食用油类别、地沟油鉴别。结论新建毛细管色谱法定量准确、简便、选择性和重现性好;构建油脂脂肪酸指纹库、辨析各类油脂特征特异点为地沟油鉴别、食用油脂类别辨析提供技术支撑。     

傅立叶变换红外光谱法分析食品及油脂中反式脂肪酸

目的：采用傅立叶变换红外光谱法定性定量分析食品及油脂中反式脂肪酸含量。方法：食品中提取的脂肪或油脂样品直接置于红外光谱仪的水平衰减全反射（HATR）部件的槽式ZnSe晶体上,氘化三甘氨酸硫酸酯（DTGS）检测器检测。通过966 cm-1处反式双键的特征峰进行定性,由峰面积与反式脂肪酸含量的线性校准曲线定量计算反式脂肪酸在油脂中的百分含量。结果：该方法可通过反式双键的特征峰对样品油脂中的反式脂肪酸进行准确定量。结论：此方法具有简单、快速、准确的特点,适用于食品营养标签的测定。     

地沟油拉曼光谱特征形态

目的寻找鉴别地沟油与食用植物油的拉曼光谱特征谱带。方法比较和分析地沟油与食用植物油拉曼光谱的形态及差异。结果在532 nm光源普通及扩展光谱中,精炼地沟油呈现平滑包状拉曼谱带,各种类型及来源不同的地沟油普遍具有与之形态相似的拉曼谱带,而各种食用植物油无一具有这一形态的拉曼谱带。通过导数扩展光谱可以有效分离精炼地沟油与食用植物油之间原本严重重叠的谱峰,而通过导数普通光谱可以测量和描述掺杂植物油中地沟油的掺入量。结论平滑包状拉曼谱带是普遍见于地沟油的指纹图谱。该指纹图谱可为鉴别地沟油与植物油,以及检测油脂样品中地沟油的掺入量提供丰富的信息及适用的标志。     

食品及油脂中反式脂肪酸含量定性定量分析方法

目的:采用气相色谱法定性定量分析食品及油脂中反式脂肪酸含量。方法:食品中提取的脂肪或油脂样品直接甲酯化,于SP-2560(100 m×0.25 mm×0.2μm)弹性石英毛细管柱上进行分离,并经FID检测器检测。通过标准品保留时间、脂肪酸甲酯的链等长值定性(ECL)及顺反式脂肪酸甲酯出峰规律进行定性,面积归一化法定量计算反式脂肪酸在油脂中的百分含量。结果:该方法可使顺反式脂肪酸甲酯得到有效分离,从而进行准确定量。结论:此方法具有简单、快速、准确的特点,适用于食品营养标签的测定。     

反式脂肪酸有多可怕?

<正>最近,美国食品与药品管理局命令食品产业逐渐停止使用反式脂肪酸,因为它对美国大众的健康产生了极大的负面影响。我们又应该如何看待反式脂肪酸呢?氢化油的诞生油脂是由甘油和脂肪酸组成的甘油三酯,其中脂肪酸的重量约占95%。脂肪酸的结构可分为饱和脂肪酸、多不饱和脂肪酸以及单不饱和脂肪酸。油脂中脂肪酸的结构决定了它是否对人体有益。含大量饱和脂肪酸的油脂是最不健康的,动物油脂(除深海鱼类油脂)就是这类不健康的油脂,吃太多有丰富油     

地沟油鉴别检测指标的研究进展

综述目前鉴别检验地沟油的常见检测指标。对地沟油和正常食用油常规检测指标和特异性检测指标进行分析。常规检验指标能区分油脂优劣,可以作为判断是否为地沟油的辅助性指标,特异性指标是今后鉴别地沟油的重点。寻找出能判断地沟油的特异性指标并建立检验方法,为执法部门提供可靠的检验依据,防止地沟油回流餐桌。     

基于辣椒碱鉴别“地沟油”的有效性评估

目的评估基于辣椒碱鉴别"地沟油"的有效性。方法采集食用植物毛油14份,煎炸废弃油脂24份,餐厨废弃油脂34份,市售食用非花生植物油32份,市售食用花生植物油32份,正常食用油加香精16份和自制"地沟油"精炼油11份,检测样品中天然辣椒碱、二氢辣椒碱、合成辣椒碱含量,对上述样品的辣椒碱检测结果以样品类别进行统计学检验,评估基于辣椒碱鉴别"地沟油"的有效性。结果辣椒碱指标检测灵敏度高,判定餐厨废弃油脂及精炼"地沟油"类样品有效性较高,准确率分别达100%及90.1%,但在食用花生植物油中有辣椒碱本底存在。结论辣椒碱在烹饪过程中作为辣椒调料添加引入的成分在油脂中能保留下来,在精炼过程中不能完全被去除,在充分排除本底干扰的情况下,结合其他指标可有效鉴别"地沟油"与食用植物油。     

基于辣椒碱鉴别“地沟油”的有效性评估北大核心CSCD

目的评估基于辣椒碱鉴别"地沟油"的有效性。方法采集食用植物毛油14份,煎炸废弃油脂24份,餐厨废弃油脂34份,市售食用非花生植物油32份,市售食用花生植物油32份,正常食用油加香精16份和自制"地沟油"精炼油11份,检测样品中天然辣椒碱、二氢辣椒碱、合成辣椒碱含量,对上述样品的辣椒碱检测结果以样品类别进行统计学检验,评估基于辣椒碱鉴别"地沟油"的有效性。结果辣椒碱指标检测灵敏度高,判定餐厨废弃油脂及精炼"地沟油"类样品有效性较高,准确率分别达100%及90.1%,但在食用花生植物油中有辣椒碱本底存在。结论辣椒碱在烹饪过程中作为辣椒调料添加引入的成分在油脂中能保留下来,在精炼过程中不能完全被去除,在充分排除本底干扰的情况下,结合其他指标可有效鉴别"地沟油"与食用植物油。     

气相色谱法检测掺假植物油方法研究

目的:建立掺假植物油的气相色谱检测方法。方法:将油脂样品用0.5 mol/L的KOH-CH3OH溶液甲酯化后用石油醚苯混合溶液提取,通过气相色谱检测分析样品的脂肪酸构成比,并根据不同油种其脂肪酸的特征组分和含量以及其特征组分的绝对量的不同来鉴别食用植物油的掺伪。结果:能有效鉴别植物油掺假比例。结论:方法简便、可靠、实用。     

潲水油等废弃食用油脂检测指标的建立研究

目的:建立简单、实用性强、适用于各种废弃食用油脂鉴别的检测方法,提高检出率,为食品卫生监督提供科学依据。方法:对市售普通食用油和废弃食用油脂的脂肪酸组分、酸价等卫生指标以及氯化钠、谷氨酸钠等指标进行检测,对检测结果进行对照比较和统计分析。结果:食用油和废弃食用油脂两类油脂酸价、羰基价、氯化钠、谷氨酸钠等指标检测结果比较差异有统计学意义(P<0.05),硬脂酸C18:0含量和过氧化值差异没有统计学意义(P>0.05)。结论:参照现有食用植物油卫生标准进行检测无法判定油脂样品是劣质油还是来源于废弃油脂,卫生学指标酸价、羰基价作为初筛指标,结合氯化钠、谷氨酸钠残留检测或脂肪酸组分分析等多个指标综合评价可以有效鉴别普通劣质油脂与各类废弃食用油脂。     

潲水油鉴别检测方法研究

目的：研究潲水油的实验室鉴别检测方法。方法：将潲水油与正品食用油进行对照研究，寻找潲水油特有的可在实验室进行检测的理化指标。结果：潲水油的感官、熔点、钠、水提取物电导率、脂肪酸组成成分等指标具有特异性，并可以用相应的检测方法进行检测。结论：本方法能应用于潲水油的鉴别检测。     

固相萃取-气相色谱/质谱法检测潲水油中的辣椒素类物质

目的 建立离子交换固相萃取-气相色谱/质谱检测油脂中辣椒素类物质的新方法。 方法 油脂类样品通过正已烷稀释、分散后,乙腈提取其中待测物,并经固相萃取浓缩、净化,氨化甲醇洗脱,衍生后气相色谱-质谱(gas chromatography-mass sepetrometry,GC-MS)测定。 结果 新方法对辣椒素类物质的检出限可达0.001 mg/kg,在浓度0.003~0.50 mg/kg范围内线性关系良好,样品加标回收率为84.0%~116%,相对标准偏差≤5.1%(n=5)。 结论 新方法灵敏、准确,检测辣椒素类由烹饪过程带入而非油脂固有的成分,作为鉴别潲水油的手段,具有良好的操作性。     

Evaluation of the composition of omega-3 fatty acids in dietary oil supplements

Aim: The aim of the present study was to determine the fatty acid composition of 19 dietary oil supplements that are commercially available in Australia, comparing findings with manufacturers' reported omega-3 fatty acid content. Methods: Fifteen fish oil supplements and four non-fish oil supplements were obtained from Australian retail stores. Fatty acids were derivatised, and fatty acid methyl esters were quantitated using classical GC-flame ionisation detection methods. Composition of eicosapentaenoic acid and docosahexaenoic acid reported by supplement manufacturers was compared with experimental values using the Bland-Altman plot. Results: The combined eicosapentaenoic acid and docosahexaenoic acid content in the fish oil and non-fish oil supplements was 17.63–71.45% and 0.00–0.05% respectively. A high level of congruency was observed for the composition of eicosapentaenoic acid and docosahexaenoic acid reported by manufacturers and determined experimentally (mean difference, eicosapentaenoic acid, 13.2 mg; docosahexaenoic acid, 12.8 mg). Conclusion: Current practice in pre-market assessment of complementary medicines in Australia is satisfactory for supplements examined in the present study. Intake of these fish oil supplements can be used to provide high levels of long-chain omega-3 fatty acids that would be otherwise difficult to achieve through normal dietary intake alone.     

散装劣质再生油、煎炸老油与合格植物油的鉴别

目的:为加强对餐饮业劣质油监督管理,建立散装再生油、煎炸老油与合格植物油的鉴别方法。方法:按国家标准食品卫生检验方法理化部分(一)GB/T5009.37-2003。结果:散装再生油、煎炸油及合格食用植物油的理化指标与国家规定食用油标准进行比对,部分散装油及煎炸老油的感观异常,特别是酸价远高于国家家庭食用油最高允许值。结论:用此方法,可作为鉴别劣质再生油、煎炸老油与合格食用油的理化指标。     

物种特异性基因扩增鉴别掺假食用植物油

目的:建立特异的掺假食用植物油鉴定方法。方法:以掺假食用油中掺入的低价值食用油相应油料作物物种特异性基因为靶标,采用普通PCR(Polymerase Chain Reaction)方法鉴定掺入一种低价值食用油的混合油样,双重PCR技术鉴定掺入两种低价值食用油的混合油样。结果:在8个按2/3量掺入一种低价值食用油的混合油样中至少在一个平行样中检出低价值食用油相应的物种特异性基因,而按1/2比例掺入低价值食用油的8个油样中有5个检出混入的低价值食用油;3个按照1∶1∶1掺入两种低价值食用油的混合油样,其掺假检出率及平行样之间重现性均较差。结论:本研究选定的掺假植物油的检测靶标具有较强特异性,可有效鉴别大量掺入低价值食用植物油的掺假油品,但对于掺假量低于50%的油品,其掺假鉴别能力尚待提高。     

市售大豆油中“地沟油”调查

目的:了解市售食用植物油是否掺入"地沟油"。方法:应用国标法对省内市场销售的68个大豆油的酸价、过氧化值、羰基价、冷冻试验、苯并芘和胆固醇等项目进行检测。结果:3个预包装样品酸价不符合GB 1535《大豆油》相应等级指标要求。4个散装样品酸价检出值较高,均超过1.0 mg/g。过氧化值在0.9 mmol/kg～4.1 mmol/kg范围间,羰基价检测值在1 meq/kg～13 meq/kg之间,8个一级大豆油冷冻试验结果为"澄清、透明",均符合GB 1535要求。25个预包装样品和有产品等级标识的17个散装样品苯并芘检测结果在1μg/kg～7μg/kg之间,符合GB 2716限量要求。胆固醇均未检出。结论:抽查的68个大豆油样品大部分检测值符合相关标准要求,但有部分样品检测值超标或检测值较高,尤其是散装样品和无企业标识样品需要进一步关注。     

Varying incorporation of fatty acids into phospholipids from muscle,adipose and pancreatic exocrine tissues and thymocytes in adult rats fed with diets rich in different fatty acids

Despite numerous studies, the importance which the tissue or the composition of the diet may have in the biological distribution of each fatty acid is not well known. To determine the importance of tissue origin and dietary fatty acids in the fatty acid composition of cell phospholipids, 54 male adult rats were fed isocaloric diets for one month varying only in their fatty acid compositions. The fat component of the six experimental groups was derived from olive oil, sunflower oil, fish oil, soybean oil, palmitic acid, or 82% palmitic acid plus 18% soybean oil, supplying the essential fatty acid. The fatty acid composition of phospholipids from thymocytes, pancreatic exocrine, muscle and adipose tissues was studied by gas-chromatography. The tissue of origin was a more important source of variation than diet in the fatty acid content of the cell phospholipids except for palmitic acid (16:0), eicosapentaenoic acid (20:5 n-3), and docosahexaenoic acid (22:6 n-3). This study points out the complexity of the interrelations between different families of fatty acids and of the specificity of each tissue to changes in the composition of dietary fatty acids, as well as the inconvenience of speaking from the dietary point of view of groups of fatty acid families based on the position of the double bond, since their individual behaviour, including saturated fatty acids, is very different in the face of dietary manipulation. The study also highlights the different behaviour of each of the fatty acids in relation to the others in the diet in each of the tissues, a circumstance which should be taken into account when evaluating the biological effects in both epidemiological and experimental studies.     

Chemopreventive effects of dietary flaxseed oil on colon tumor development

Fatty acid composition of dietary fat, primarily the levels of omega-3 and omega-6 polyunsaturated fatty acids, has shown profound effect on colon tumor development in animal studies. Fats containing omega-6 fatty acids (for example, corn oil) enhanced and omega-3 fatty acids (for example, fish oil and mustard oil) reduced chemically induced colon tumors in rats. The purpose of this study was to investigate the effects of dietary flaxseed oil (containing alpha-linolenic acid, an omega-3 polyunsaturated fatty acid) on azoxymethane-induced colon tumor in rats and how it compared with the dietary corn oil-treated group. Male Fischer rats, separated into 2 groups of 30, were assigned to the AIN-93M diet, which was supplemented with either 15% corn oil or 15% flaxseed oil. Carcinogenesis was initiated with subcutaneous injections of azoxymethane (15 mg/kg) once a week for three consecutive weeks. Thirty-five weeks after initiation, the rats were sacrificed under ether anesthesia. Blood was collected by cardiac puncture. The gastrointestinal tract was isolated and flushed with ice-cold normal saline. The site, size, and number of tumors were recorded. The incidence and multiplicity of the tumors in the colon were determined. The fatty acid composition in the serum, colon, and tumors was estimated by using gas chromatography-flame ionization detection. Colon tumor incidence was found to be 100% and 54%, whereas multiplicity was found to be 3.1 and 0.7 tumors per rat in corn oil- and flaxseed oil-treated groups, respectively. Tumor size was significantly larger in the corn oil-treated group than in the flaxseed oil group. Colon and serum samples of the corn oil group showed an increase in the omega-6 fatty acid levels, whereas the flaxseed oil group exhibited an increase in the omega-3 fatty acid levels. The results indicate that dietary flaxseed oil, containing high levels of omega-3 fatty acids, is effective in preventing colon tumor development when compared with dietary corn oil containing omega-6 fatty acids in rats.     

Effect of fish oil pretreatment on isoproterenol-induced changes in myocardial membrane phospholipids

OBJECTIVE: In the present study, the protective effect of fish oil treatment on the fatty acid composition in isoproterenol (IPH)-induced myocardial infarction was studied in male albino Wistar rats. METHODS: Rats were injected for 2 consecutive days with IPH (60 mg/kg body weight) at 24-h intervals to induce myocardial infarction. Fish oil was administered orally at a dose of 0.05 mL/d for 45 d, after which serum and heart tissue were assayed for lipid profile, lipoprotein changes, and myocardial membrane phospholipid fatty acid composition. RESULTS: Biochemical assessment of myocardial infarction was done by measuring the activities of creatinine kinase and lactate dehydrogenase, which were significantly elevated in the rats administered with IPH. Further, the administration of IPH modified the fatty acid composition and analysis of fatty acids showed there was an increase in the omega-3/omega-6 ratio in phospholipid pool. In addition, increased levels of total cholesterol, free cholesterol, ester cholesterol, phospholipids, triacylglycerols and free fatty acid was observed in serum and heart tissue of IPH-induced rats. The fish oil treatment for a period of 45 d decreased the levels of cardiac markers (creatinine kinase and lactate dehydrogenase) and reversed the biochemical lesions induced by IPH. CONCLUSION: Our study suggests that fish oil treatment has a hypolipidemic effect and has potential use in the treatment of myocardial infarction.