食用油与人体健康

随着人们生活水平的提高和我国新的食用油标准的实施,食用油越来越受到人们的关注。从食用油的主要化学成分、对人体健康的影响、科学合理的膳食等方面介绍食用油的知识。     

大气压化学电离-高分辨质谱直接分析食用油中的甘油三酯

建立了食用油中甘油三酯的大气压化学电离-质谱直接分析检测方法.在考察实验条件影响的基础上,选择乙腈作为溶剂,正离子检测模式,进样流速为800 μL/h,喷雾器温度250℃,电晕针电流为5000 nA.用本方法对10种食用油进行分析,结果表明,植物油与动物油之间差异较大.经主成分分析,选择m/z 857.76与m/z 881.76峰强度比作为指标,重复性RSD＜5％,可直接识别出玉米油中掺杂5％的猪油.用碰撞诱导解离(CID)实验初步鉴别了食用油的3个特征峰.利用本方法对泔水油样品和煎炸油样品进行分析,结果泔水油样品中含有植物油和动物油,而煎炸油样品也与商品食用油存在差异.本方法可用于食用油样品的快速筛查.     

色谱指纹谱鉴定食用油品质

随着生活水平的提高,人们对食用油品质的要求也逐渐提高,有必要开发一种快速鉴定食用油品质的方法.食用油的数字化指纹谱的建立借鉴了中药数字化的指纹谱的方法,此方法可应用于食用油的质量控制、真伪鉴别、氧化变质控制等.特征指纹峰的提出保证了鉴定的客观性、科学l生和公正性,也增加了其全面性.食用油的数字化指纹谱的建立为食用油的质量控制提供一种快速、准确、稳定的鉴定方法.     

食用油识别方法的研究

建立了用气相色谱－氢火焰离子检测器（ＧＣ－ＦＩＤ）准确测定了各种食用油中所有脂肪酸含量的方法，提出用脂肪酸含量的分布和相对不饱和度（Ｕ／Ｓ）来识别食用油，识别模型简便可靠，从而达到识别掺假的目的。     

人工神经网络用于直接化学电离质谱分析食用油品质的研究

无需任何样品预处理,采用表面解吸常压化学电离质谱(DAPCI-MS)技术直接对涂覆在载玻片表面的食用油样品和地沟油样品进行检测,快速获得了不同油类样品的质谱信号;并运用改进的反向传输(BP)人工神经网络对DAPCI-MS所得到的油类样品质谱数据进行有监督的分类识别,建立多分组预测模型。结果表明:DAPCI-MS能够承受食用油中复杂基体的影响,可对油类样品进行直接快速质谱分析;误差反转(BP)神经网络具有良好的分类判别能力,对食用油样品质谱数据识别效果比较理想,能够在对地沟油和非地沟油样品进行有效区分的同时,实现对不同品种的食用油的分离及分类判别。本方法分析速度快,信息提取准确,识别精度高,对快速质谱技术结合神经网络在该领域的应用以及食用油品质的快速鉴定具有重要的借鉴意义。     

食用油脂质过氧化的气相色谱／质谱法定性研究

食用油受热或放置时间过长会产生一系列自由基反应形成脂质过氧化物,并进一步分解成含羰基、环氧基等小分子化合物。用气相色谱／质谱联用方法对存放不同时间的５份食用油中挥发性的脂质过氧化分解物进行了定性分析。在存放２年和３年的食用油中分别鉴别出８和１６个化合物。己醛、２,４－癸二烯醛相对含量较高。     

非正常食用油的在线甲基化-气相色谱测定及模式识别分析研究

建立了食用油中脂肪酸组成的在线水解甲基化-气相色谱测定方法,分析了20余种常用食用油与非正常食用油样品。将1μL(3 mg/mL)油脂样品与2μL衍生化试剂四甲基氢氧化铵(TMAH,25%甲醇溶液)加入裂解器,在350℃下,油脂加水分解瞬间衍生化成相应的脂肪酸甲酯。基于气相色谱图上分离鉴定到的10个共有峰的相对强度,建立了食用油的气相色谱指纹图谱。结合化学模式识别即主成分分析和系统聚类分析对合格食用油和非正常食用油样品的色谱图进行了识别分析。结果表明,建立的指纹图谱结合模式识别技术可以较好的区分合格食用油与非正常食用油样品。     

GC-MS法鉴别食用油和餐饮业中废弃油脂的研究

用气相色谱 质谱联用(GC MS)方法对7种餐饮业中废弃油脂(简称废油脂)和5种合格成品食用油(简称食用油)中所有脂肪酸进行分析。研究发现,废油脂中部分不饱和脂肪酸受到氧化,使脂肪酸相对不饱和度(U R)值明显小于同种类食用油中的脂肪酸相对不饱和度(U R)值,其脂肪酸的质量分数分布与同种类的食用油中脂肪酸的质量分数分布有很大的区别,以及绝大部分废油脂中存在较大量矿物油。研究表明,脂肪酸相对不饱和度(U R)值和脂肪酸的质量分数分布可以鉴别废油脂。     

食用油中脂肪酸含量的气相色谱分析

随着人们物质生活水平的提高,国内外对食用油中脂肪酸成分的研究日益重视。为测定食用油中脂肪酸成分,我们用高效毛细管色谱法,使饱和脂肪酸,特别是多种不饱和脂肪酸得到很好的分离和测定。本工作采用快速酯交换法代替常规的脂肪酸甲酯的制备方法,对食用油脂进行了色谱分析并将两种方法所测数据进行对比。     

基于相转移技术的劣质食用油快速可视化检测方法

近年来,劣质油流入成品食用油市场引起的地沟油事件,导致了严重的食品安全隐患和社会负面反响.本研究结合可视化和相转移技术,建立了以铜离子和聚二烯丙基二甲基氯化铵（PDDA）修饰的阳离子纳米金为探针的两种简单、准确、灵敏的劣质食用油现场快速检测方法.结果表明,两种方法均可检测到合格食用油中掺入2.8%的劣质油含量,大于5%掺入量可明确测定.将上述方法分别应用于共235个样品的盲测,结果显示,总准确率达95.7%.本工作为劣质食用油的快速现场检测提供了有益的参考方法.     

蓖麻油和聚氧乙基蓖麻油的结构和组成的波谱表征

核磁共振波谱法;质谱法;红外光谱法;蓖麻油和聚氧乙基蓖麻油的结构和组成的波谱表征     

Determination of Organophosphorus Pesticides in Soybean Oil, Peanut Oil and Sesame Oil by Low-Temperature Extraction and GC-FPD

A low-temperature clean-up method for residue determination was developed and validated for 14 organophosphorus pesticides in soybean oil, peanut oil and sesame oil by gas chromatography with flame photometric detector (GC-FPD). A different matrix influenced the response and retention time of pesticides. Hence matrix-matched calibration standards were used to counteract the matrix effect. The pesticide responses in blank samples of soybean oil, peanut oil and sesame oil were within the linear range of 0.02–1 mg kg⁻¹ and the correlation coefficients were higher than 0.9989. Average recoveries obtained from different oil samples at three fortified levels were higher than 50% with relative standard deviations (RSDs) of less than 15%. The limit of detections (LODs) of studied pesticides ranged from 2 to 5 μg kg⁻¹. Thirty-nine commercial samples were analyzed, and the results were confirmed by gas chromatography–mass spectrometry (GC–MS) in selective ion monitoring (SIM) mode.     

费谢尔判别法鉴别原油/燃料油

以多环芳烃作为变量,建立了原油、燃料油属性鉴别的费谢尔判别法。分别测定了来自不同国家和地区的26个原油样品和25个燃料油样品中8种多环芳烃的含量,并将它们作为判别变量。借助SPSS 16.0进行费谢尔判别分析,建立费谢尔判别函数。将未知样品的判别变量值代入后,可以快速地得知样品的类别。结果表明,以多环芳烃作为判别变量进行原油、燃料油费谢尔判别快速而准确。     

快速测定植物油胆固醇含量在地沟油筛查中的应用

采用皂化气相色谱氢火焰离子检测器法测试了多个植物油样品,发现胆固醇峰被干扰比较严重,很难得出植物油与地沟油胆固醇含量的界定值。采用SPE进行样品前处理,对SPE处理条件进行优化,得出优化条件为称样量0.25 g ,20 mL 0.6%乙醚-正己烷(V/V)作为淋洗液,20 mL 15%乙醚-正己烷(V/V)作为洗脱液。用SPE气相色谱氢火焰离子检测器法分析了84个植物油样品和13个地沟油样品中胆固醇含量,测定结果表明,植物油胆固醇含量与地沟油胆固醇含量有明显区别,所有植物油胆固醇含量都小于50μg/g,13个地沟油样中11个样胆固醇含量大于50μg/g。因此,采用上述植物油胆固醇测定方法,胆固醇含量超过50μg/g可判定为疑似地沟油,反之不成立。本方法在0~760 mg/L浓度范围内相关系数R2=0.9999,方法检出限为6. 0μg/g,两个浓度水平(17.7和695 mg/L)的相对标准偏差分别为1.6%和1.5%,回收率为103%。     

区分动植物油的气相色谱-质谱分析

在实际办案中,经常需要对附着在不同载体上的油脂斑痕进行检验,嫌疑斑痕为何类何种油脂对案件的侦破有重大意义.各个领域的专家对动植物油的成分进行研究的目的各不相同,食品工业中偏重于动植物油的食用价值,医学中偏重研究油脂对身体的益处或危害,而司法鉴定领域,偏重于对常见油类进行定性分析,从而为侦查破案提供线索.     

Oil and gas production

Colloid and interface science is fundamental to many aspects of oil and gas production processes. This review focuses on recent advances in water-based drilling fluids, reservoir fracturing fluids, polymer gels for modifying reservoir permeability, avoiding problems caused by colloidal asphaltene oil fractions and characterising the wettability of reservoir rocks. There have been major advances in the design and responsiveness of polymer and surfactant fluids, in the understanding and control of shale clayrock swelling and in the relationships between mesoscopic-scale phenomena in porous media and reservoir production performance.     

Neem Oil As Pesticide

Use of synthetic pesticides has resulted into health hazards, ecological imbalance, resistance in pests and environmental pollution.1 Singh, R. 1997. “Studies in formulation of pesticide emulsion”. India: UDCT, University of Mumbai. , Ph.D. Thesis [Google Scholar] Neem oil is natural pesticide and has excellent insecticidal properties. Hence, attempts are being made to develop neem oil emulsions to be used as pesticide. Surfactants like castor‐oil based, nonyl phenol‐based, sodium lauryl sulphate, and calcium alkyl benzene sulphonate were tried to develop stable emulsions. Neem extract based emulsifiable concentrates were prepared by using methanol. Stability of emulsion as a function of type of surfactants, hydrophile‐lipophile balance (HLB) of surfactants and hardness of water was studied. Larvasidal effects of emulsions and emulsifiable concentrates were examined. Laboratory experiments have shown effectiveness of these emulsions and emulsifiable concentrates as pesticide.     

Lipase-Catalyzed Preparation of Diacylglycerol-Enriched Oil from High-Acid Rice Bran Oil in Solvent-Free System

The ability of immobilized lipase from Rhizomucor miehei (Lipozyme RM IM) to catalyze the reaction of high-acid rice bran oil (RBO) and monoglyceride (MG) for diacylglycerol-enriched rice bran oil (RBO-DG) preparation was investigated. The effects of substrate ratio, reaction temperature, time, and enzyme load on the respective content of free fatty acid (FFA) and DG in the final RBO-DG products was investigated. Enzyme screening on the reaction was also investigated. Response surface methodology (RSM) was used to optimize the effects of the reaction temperature (50?C70?°C), the enzyme load (2?C6?%; relative to the weight of total substrates), and the reaction time (4?C8?h) on the respective content of FFA and DG. Validation of the RSM model was verified by the good agreement between the experimental and the predicted values. The optimum preparation conditions were as follows: MG/RBO, 0.25; temperature, 56?°C; enzyme load, 4.77?%; and reaction time, 5.75?h. Under the suggested conditions, the respective content of FFA and DG was 0.28 and 27.98?%, respectively. Repeated reaction tests indicated that Lipozyme RM IM could be used nine times under the optimum conditions with 90?% of its original catalytic activity still retained.     

荧光分光光度法测定矿物油的标准油选择研究

本文研究了我国37种原油、机油和柴油的荧光激发光谱和发射光谱特征。提出用比值法或发射波长法将矿物油分组,尔后选择相应的标准油。该法克服了统一方法制取标准油烦琐、费时的缺点。