植物油对被孢霉菌发酵生产花生四烯酸的影响

研究了四种植物油(豆油、棕榈油、花生油、芝麻油)对被孢霉菌发酵生产花生四烯酸(Arachidonic acid, AA)的影响.结果表明:(1)四种植物油显著促进了菌体油脂的积累;(2)被孢霉生长在以植物油为唯一碳源的培养基上时,菌体油脂中的AA含量比以葡萄糖为碳源时显著下降;生长在以植物油和葡萄糖为混合碳源的培养基上时,与以葡萄糖为碳源相比油脂中的AA含量仍然下降,但比生长在以植物油为唯一碳源时AA含量有所提高.说明这四种植物油对花生四烯酸的合成有抑制作用.(3)菌体油脂成分与培养基中植物油的油脂成分有一定的相似性.     

拉曼光谱-聚类分析法快速鉴别掺伪花生油

目的建立快速鉴别掺伪花生油的拉曼光谱.聚类分析方法。方法以不同产地、不同品牌的多批次花生油、大豆油、玉米油、菜籽油、葵花籽油、精炼棕榈油、精炼棉籽油及精炼地沟油为样品,在780 nm和532 nm激光光源下,扫描和比较其普通、扩展及导数拉曼光谱的形态。结果在532 nm激光光源的扩展光谱及一阶导数光谱中,花生油与低价植物油及精炼地沟油光谱的信息量最大,样品间光谱形态的差异显著,谱峰得到有效分离。基于此全波段光谱信息和形态建立的多步聚类分析模型及鉴别程序对36份不同花生油、105份不同低价植物油、30份仿冒花生油和38份不同精炼地沟油的判别正确率均为100%,对180份5%及以上的掺假花生油的判别正确率达86%以上,对75份5%及以上的掺杂花生油的判别正确率为92%,对72份5%及以上的掺杂植物油的判别正确率达92%以上。样品测量时无需制备样品及消耗化学试剂,测量和分析一份样品仅耗时5 min左右。结论所建立的拉曼光谱.聚类分析模型既可准确鉴定花生油,还可准确鉴定各种类型的掺伪花生油,可实现对掺伪花生油的快速、无损和准确鉴别。     

A high performance liquid chromatography method for determination of furfural in crude palm oil

A modified steam distillation method was developed to extract furfural from crude palm oil (CPO). The collected distillates were analysed using high performance liquid chromatography (HPLC) coupled with an ultraviolet diode detector at 284 nm. The HPLC method allowed identification and quantification of furfural in CPO. The unique thermal extraction of CPO whereby the fresh fruit bunches (FFB) are first subjected to steam treatment, distinguishes itself from other solvent-extracted or cold-pressed vegetable oils. The presence of furfural was also determined in the fresh palm oil from FFB (without undergoing the normal extraction process), palm olein, palm stearin, olive oil, coconut oil, sunflower oil, soya oil and corn oil. The chromatograms of the extracts were compared to that of standard furfural. Furfural was only detected in CPO. The CPO consignments obtained from four mills were shown to contain 7.54 to 20.60 mg/kg furfural.     

Simultaneous Determination of Chlorophylls, Pheophytins, β-Carotene, Tocopherols, and Tocotrienols in Olive and Soybean Oils by High-performance Liquid Chromatography

A high‐performance liquid chromatographic method is described for the simultaneous measurement of chlorophylls, pheophytins, β‐carotene, tocopherols, and tocotrienols in vegetable oils using 2 spectrophotometers in series and 1 normal‐phase silica column. Oil samples were diluted in the mobile phase, isopropanol‐hexane (1.5:98.5 vol/vol), and injected directly onto the column. A programmable UV/Vis spectrophotometer was used to measure chlorophylls a and b, pheophytins a and b, and β‐carotene at their appropriate absorption maxima (430, 452, 409, 433, and 452 nm, respectively). α‐, γ‐, and δ‐tocopherols and α‐, γ‐, and δ‐tocotrienols were measured by fluorescence at 295‐nm excitation and 330‐nm emission. Samples of virgin olive oil, soybean oil, and palm oil were analyzed.     

基于拉曼光谱-聚类分析快速鉴别掺伪油茶籽油

在532 nm激光光源的扩展拉曼光谱及一阶导数光谱中,油茶籽油与低价植物油及精炼地沟油光谱形态的差异显著,谱峰得到有效分离。基于全波段光谱信息和形态建立的多步聚类分析模型既可准确鉴定油茶籽油,还可准确鉴定各种类型的掺伪油茶籽油。对26份不同油茶籽油、105份不同低价植物油、75份5%及以上的掺杂油茶籽油和38份不同精炼地沟油的判别正确率均为100%,对5%及以上的180份掺假油茶籽油和72份掺杂植物油的判别正确率达92%以上。样品测量时无需制备样品及消耗化学试剂,测量和分析1份样品仅耗时5 min左右,可实现对掺伪油茶籽油的快速、无损和准确鉴别。     

常规加热和微波加热对两种植物油维生素E含量的影响

目的 研究常规加热和微波加热两种加热方式对植物油中维生素E的8种异构体的影响。方法 大豆油、棕榈油进行常规加热和微波加热后, 用异辛烷进行超声提取, 最后用正相高压液相色谱法测定。结果 两种加热方式都会使植物油中维生素E的含量降低, 其中微波加热对维生素E的影响更大。结论 加热时间过长会影响植物油的品质, 同时也能通过对植物油中维生素E的检测推论该植物油是否经过加热处理。     

Removal of organochlorines from vegetable oils and its benefits in preventing formation of monochloropropanediol diesters

This paper reports the first results on depleting certain organochlorines from vegetable oils without the use of any solvent in order to mitigate monochloropropanediol diesters (MCDPE). The concept is based on separating the organochlorines from the bulk oil by using trapping agents (e.g. monoacylglycerols) that can be easily separated from the oil. The process starts by mixing and homogenizing crude vegetable oils with the trapping agent and subsequently separating the trapping agent from the oil bulk via crystallization. The proof-of-concept of the approach is demonstrated on a spiked sunflower model system, solvent extracted crude sunflower oil, industrially produced crude soybean and corn oils. The depletion of organochlorines in the crude oils and its beneficial effect on the MCPDE content in the heat treated samples is measured by LC-MS. The depletion efficacy of the monitored organochlorines was estimated to be in the 60–95 % range. Both the melting point and polarity of the trapping agents affected the depletion efficacy of the organochlorines. Trapping agents with higher melting point and polarity, such as monostearin were more effective in comparison to high melting point but less polar agents such as palm stearin or agents rich in polar but low melting point monolinolein/monoolein. The effect of organochlorine depletion on the subsequent MPCDE levels in heat treated oil was in the range of 60–90 % reduction depending on the type of the studied oil.     

拉曼光谱-聚类分析快速鉴别掺伪芝麻油

目的建立快速鉴别掺伪芝麻油的拉曼光谱-聚类分析方法。方法以不同产地、不同品牌的多批次芝麻油、大豆油、玉米油、菜籽油、精炼棕榈油、精炼棉籽油及精炼地沟油为样品,在780 nm和532 nm激光光源下,扫描和比较其普通、扩展及导数拉曼光谱的形态。结果在532 nm激光光源的扩展光谱及一阶导数光谱中,芝麻油与低价植物油及精炼地沟油光谱的信息量最大,样品间光谱形态的差异显著。基于此全波段光谱信息和形态建立的多步聚类分析模型对芝麻油、低价植物油、仿冒芝麻油和精炼地沟油的判别正确率均为100%;对5%、10%、20%、30%和50%掺假芝麻油的判别正确率分别为72%、92%、100%、100%和100%;对5%、10%和20%掺杂芝麻油的判别正确率分别为97%、100%和100%;对5%、10%和20%掺杂植物油的判别正确率分别为94%、100%和100%。样品测量时无需制备样品及消耗化学试剂,测量和分析一份样品仅耗时5 min左右。结论所建立的拉曼光谱-聚类分析模型既可准确鉴定芝麻油,还可准确鉴定各种类型的掺伪芝麻油,可实现对掺伪芝麻油的快速、无损和准确鉴别。     

3种植物油傅里叶变换红外光谱信息的判别分析研究

针对花生油、大豆油和棕榈油样品,采用傅里叶变换红外光谱仪,采集红外吸收光谱,对光谱预处理后,提取红外特征信息,以1 746 cm-1和2 855 cm-1波数处吸收峰特征参数比值为X轴, 1 099 cm-1与1 119 cm-1波数处吸收峰特征参数的比值为Y轴,及3种油O-C-C对称伸缩振动各自所产生的吸收带所在波数(cm-1)值作为Z轴,绘制三维分布图,对这3种油样进行判别分析.结果显示这3种油样之间有明显区分.     

食用植物油中掺混棕榈油的定性与定量分析

目的建立食用植物油中掺混棕榈油的定性与定量分析方法,为植物油掺假提供检测依据。方法植物油样品先经过皂化和甲酯化处理,然后采用气相色谱法对植物油中的各种脂肪酸组成进行检测。以月桂酸为特征指标,直接定性,应用面积归一化法进行定量分析。结果配比实验验证和检测数据分析表明,该方法月桂酸检出限为0.01%,植物油中棕榈油的定量限为5%~100%,最低可以分辨出添加了5%棕榈油的食用植物油样品。结论此方法操作简单、重现性好、精确度高,是一种分析迅速、经济实用的分析方法。     

Determination of high molecular mass polycyclic aromatic hydrocarbons in refined olive pomace and other vegetable oils

A new and simple method has been developed for determining high molecular mass polycyclic aromatic hydrocarbons (PAHs) in refined olive pomace, and other vegetable oils from an initial sample of 0.25 g. The hydrocarbon fraction is isolated by solid‐phase extraction (SPE) on silica gel using hexane as eluent. The fraction is evaporated to reduced volume and cleaned‐up by SPE on an amino phase eluting with toluene. The evaporated residue, dissolved in acetonitrile, is analyzed by reverse‐phase high‐performance liquid chromatography with fluorescence detector using programmed excitation and emission wavelengths. The benzo(e)pyrene is determined together with other usual heavy PAHs. Interferences due to squalene and other hydrocarbons are minimized. Recoveries were greater than 80% and detection limits ranged from 0.01 to 0.2 µg kg^?1. The method was validated using certified oil samples and was applied to various vegetable oils. Copyright © 2004 Society of Chemical Industry     

基于傅里叶变换红外光谱的大豆原油掺伪定量 分析模型研究

目的应用傅里叶变换红外光谱(FTIR)结合最小偏二乘法(PLS)建立大豆原油-棕榈油二元掺伪体系的定量分析模型。方法以42个大豆原油、21个精炼油、88个掺伪油的FIIR谱图为模型样本,预处理方法选用标准正态变量(SNV),在此基础上应用主成分分析(PCA)提取特征变量,随机选取60个掺伪油样组成校正集,28个掺伪油样组成验证集,以PLS方法建立大豆原油的掺伪定量模型。结果 PCA可将大豆原油及精炼油分成独立的2类。经PCA分析,大豆原油中掺入棕榈油的掺伪检测限为5%。PLS校正模型的判定系数R2为0.9926,校正误差均方根RMSEC为1.8121。预测模型的R2为0.9823,交叉验证误差均方根RMSECV为2.8189。同时得到的预测结果的偏差在1.3909%~3.1019%之间,差异不显著,说明此模型可行。结论 FTIR-PLS模型能够实现大豆原油的掺伪定量分析,分析速度快,能够满足大豆原油入库要求,是一种可行的大豆原油掺伪分析方法。     

Factors impacting the formation of Monochloropropanediol (MCPD) fatty acid diesters during palm (Elaeis guineensis) oil production

Recently, organic and inorganic chlorinated compounds were detected in crude and commercially refined palm oils. Further, the predominant formation mechanism of monochloropropanediol (MCPD) diesters at high temperatures (>170–180°C) was revealed. The present study involved the development and comparison of solutions to mitigate MCPD diester levels in oils from various stages of palm oil production. Partially refined palm oil samples and oil extracted from fresh palm fruits were submitted to bench-top deodorisation experiments. Application of glycerol and ethanol as refining aids during the deodorisation of refined-bleached palm oil proved to be moderately effective; about 25%–35% reduction of MCPD diester levels was achieved. Washing crude palm oil with ethanol–water (1:1) prior to deodorisation was also an effective strategy yielding an ～30% reduction of MCPD diester contents. Washing palm fruit pulp before oil extraction, however, was most impactful, resulting in a 95% reduction of MCPD diesters when compared to the deodorised control oil. This suggests that intervention upstream in the process chain is most efficient in reducing levels of these contaminants in refined oils. Following the study, a root-cause analysis was performed in order to map the parameters potentially responsible for the occurrence of MCPD diesters in refined palm oil and related fractions.     

A study on monitoring of frying performance and oxidative stability of cottonseed and palm oil blends in comparison with original oils

Blending polyunsaturated oils with highly saturated or monounsaturated oils has been studied extensively; however, in literature there is negligible information available on the blending of refined cottonseed oil with palm olein oil. Blending could enhance the stability and quality of cottonseed oil during the frying process. In the present study, the effects of frying conditions on physicochemical properties of the palm olein-cottonseed oil blends (1:0, 3:2, 1:1, 2:3, and 0:1, w/w) were determined and compared to the pure oils. The frying process of frozen French fries was performed in duplicate at 170 ± 5°C for 10 h without interruption. The oil degradations were characterized during deep-frying applications; peroxide, free fatty acid, and iodine value by standardized methods, fatty acid profile by using a gas chromatography-flame ionization detector, polar and polymeric compounds by using the high-performance size exclusion chromatography/evaporative light scattering detector technique. The present study clearly indicated that the oxidative and frying performances of pure palm olein oil and cottonseed oil significantly improved by blending application. Results clearly indicated that the frying performance of cottonseed oil significantly improved by the blending with palm olein oil. Except that free fatty acid content, all the physicochemical variables were significantly influenced by type of pure and blend oils. By increasing the proportion of palm olein oil in cottonseed oil, the levels of polyunsaturated fatty acids decreased, while saturated fatty acid content increased. The progression of oxidation was basically followed by detecting polar and polymeric compounds. The fastest increments for polar and polymeric compounds were found as 6.30% level in pure cottonseed oil and as 7.07% level in 40% cottonseed oil:60% palm olein oil blend. The least increments were detected as 5.40% level in 40% cottonseed oil:60% palm olein oil blend and 2.27% level in 50% cottonseed oil:50% palm olein oil blend. These levels were considerably below the acceptable levels recommended by the official codex. Therefore, the present study suggested that blending of cottonseed oil with palm olein oil provided the oil blends (50% cottonseed oil:50% palm olein oil and 40% cottonseed oil:60% palm olein oil, w/w) with more desirable properties for human nutrition.     

Use of 1-acetoxypinoresinol to authenticate Picual olive oils

Picual olive oils may represent 25% of the world olive oil production. This monovarietal oil is highly valued from a nutritional viewpoint because of its high content of monounsaturated acid and polyphenols. This study reports a method to authenticate virgin olive oils of the Picual variety. The method was based on the very low content of the lignan 1-acetoxypinoresinol in these oils. The compound, as well as the other phenolic substances, was extracted from oil by using N,N -dimethylformamide (DMF), the extract was washed with hexane and nitrogen was bubbled into the solution. The identification and quantification of the lignan used HPLC to separate, followed by UV, electrochemical, fluorescence and mass spectrometry detection or gas chromatography (GC) coupled to a mass spectrometry detector. UV detection offered low sensitivity and peaks coeluting with 1-acetoxypinoresinol were also observed. Mass spectrometry detection clearly discriminated between olive oils of Picual variety and other Spanish varieties. However, lignans show a very high response to fluorescence excitation, this detector is cheaper than mass spectrometry detectors and therefore it was considered as more appropriate for industrial uses. Thus, the latter method allowed discrimination between thirty-eight Picual olive oils and eight oils of the Hojiblanca, Cornicabra, Empeltre and Arbequina varieties. The paper also demonstrated the possibility of analysing all the phenolic compounds in virgin olive oil by fluorescence. Using this technique an easy methodology to authenticate Picual olive oils was developed.     

植物油在婴儿配方乳粉中的应用探讨

从婴儿配方乳粉在用的7种植物油(大豆油、玉米油、核桃油、葵花籽油、高油酸葵花籽油、棕榈油和椰子油)入手,通过检测植物油的脂肪酸含量,对亚油酸、亚麻酸和油酸等几个主要指标进行了分析,进而与3种新型植物油(双低菜籽油、米糠油和红花籽油)的脂肪酸组成进行了比较,对新型植物油在婴儿配方乳粉中的应用进行了探讨。     

同步荧光光谱法快速鉴别食用油

利用同步荧光光谱法鉴别沙棘果油、沙棘籽油、核桃油、菜籽油、芝麻油、亚麻仁油。结果显示：不同食 用油荧光光谱具有明显的差异,在激发波长250～720 nm范围内,沙棘果油、沙棘籽油、核桃油、亚麻仁油、芝麻 油和菜籽油的最大激发波长范围分别为315～450、520～650、315～490、300～500、300～550、300～490 nm。在 激发光与发射光波长差为90 nm、激发波长250～720 nm的条件下,对6 种不同食用油进行同步荧光扫描,利用主成 分分析得分图可以直观、快速地区分鉴别各种食用油。     

Fast simultaneous determination of capsaicin,dihydrocapsaicin and nonivamide for detecting adulteration in edible and crude vegetable oils by UPLC-MS/MS

Capsaicinoids are pungent components in hot peppers, which have been detected in waste cooking oil. However, trace analysis of capsaicinoids in edible and crude vegetable oils is a challenging task due to the complex matrix. In this study, a simple liquid-liquid extraction and solid phase extraction (SPE) coupled with RP-UPLC-ESI-MS/MS method was developed for the quantification of capsaicinoids in edible and crude vegetable oils to screen the adulteration with waste cooking oil. This method was used to simultaneously determine 3 capsaicinoids (capsaicin, dihydrocapsaicin, and nordihydrocapsaicin) with capsaicin-d₃, and dihydrocapsaicin-d₃ as internal standards. This method allows the complete analysis of a sample in only an hour, even including sample preparation and chromatographic separation. The linear range of 3 capsaicinoids ranged between 0.5 and 40 µg/kg. The limit of detection (LOD) and limit of quantification (LOQ) for capsaicinoids were calculated as 0.15 and 0.5 µg/kg, respectively. Quantitative recoveries ranging from 92.9% to 105% were obtained by the analysis of spiked oil. The relative standard deviations were less than 5% (n = 6). The established method can potentially overcome the interference of triacylglycerols and fatty acids in edible and crude vegetable oils, and have been successfully applied to analyse real oil samples. This method provided a rapid and reliable method for the detection of adulteration of vegetable oils with waste cooking oils.     

婴幼儿配方奶粉及其配料油脂成分中有害酯类的污染差异分析

建立油脂和奶粉中3-氯丙醇酯、2-氯丙醇酯和缩水甘油酯的气相色谱-质谱检测方法,测定植物油脂及婴幼儿配方奶粉中的酯类污染物含量,并开展3 种有害酯类在不同种类油脂中的污染差异分析,以及与奶粉脂肪含量的相关性研究。婴幼儿配方奶粉常用植物油配料种类中,棕榈油是污染水平最高的油脂品种;其次是菜籽油、大豆油、玉米油和食用植物调和油;葵花籽油、椰子油、核桃油、亚麻籽油污染水平较低;1,3-二油酸-2-棕榈酸甘油三酯（1,3-dioleic acid-2-triglyceride palmitate,OPO）结构油脂、食用植物调合油（含OPO）污染水平最低。95 份婴幼儿配方奶粉中88.4%检出3-氯-1,2-丙二醇酯（3-monochloropropane-1,2-diol ester,3-MCPDE）,含量范围为ND～0.231 mg/kg,平均值0.070 4 mg/kg,中位值0.064 5 mg/kg;42.1%检出2-MCPDE,含量在ND～0.034 mg/kg之间;缩水甘油酯的检出率为2.1%,含量为ND～0.019 mg/kg。10.5%的奶粉样本中3-MCPDE含量超过欧盟0.125 mg/kg的限量值。奶粉中3 种酯类污染物总量与奶粉脂肪含量之间存在显著正相关,Pearson相关系数为0.453。为保护婴幼儿的安全,生产厂家应谨慎选择原料油脂,在确保营养健康的基础上尽可能降低婴幼儿配方奶粉中有害酯类的污染。     

基于GC-IMS分析三种植物油炒制海鲈鱼鱼松中挥发性风味物质的研究

本研究以海鲈鱼鱼松为研究对象,通过感官评分、色差和质构确定了植物油最佳添加量为3%。在此基础上,采用气相色谱-离子迁移谱（Gas Chromatography-Ion Mobility Spectroscopy,GC-IMS）技术深入分析了三种植物油（花生油、棕榈油和葵花籽油）炒制鱼松过程中挥发性风味物质的组成情况。结果表明,三种植物油炒制的鱼松中共鉴定出40种挥发性风味物质,包括醛类、醇类、酯类和酮类化合物等,其中,花生油、棕榈油和葵花籽油炒制鱼松中醛类的相对含量最高,分别为63.33%、57.58%和43.75%。不同植物油炒制鱼松中存在特征风味物质,其中,丙醛、苯甲醛分别只存在于花生油、棕榈油炒制鱼松中;3-甲基-1-丁醇和己醛同时存在于花生油和葵花籽油炒制鱼松中。本研究结果表明根据GC-IMS建立的三种植物油炒制鱼松指纹图谱相似度较低,能有效区分炒制鱼松的植物油来源,可作为植物油炒制鱼松的鉴定及掺伪鉴别的有效手段。