Detecting vegetable oil adulteration in hazelnut paste (Corylus avellana L.)

The possibilities of detecting hazelnut paste adulterated with refined and non-refined vegetable oils have been studied. Research was focussed mainly on peanut, high oleic-acid sunflower, corn and soybean oils which have a similar composition to hazelnut oil. The analytical procedures to detect fatty acid (FA), triacylglycerol (TAG) and tocopherol profiles as indicators of adulteration were determined. The better indicators experimentally determined were seven FA (palmitic, stearic, linoleic, linolenic, arachidonic, behenic and lignoceric acids) and different TAG with three unsaturated FA (the code letters used for FA are: P = C_16:0; S = C_18:0; O = C_18:1; L = C_18:2;; L_n = C_18:3) (LLL_n, LLL and OOO), two unsaturated FA (POL, PLL and SOO), and one unsaturated FA (PPL). As expected, when refined vegetable oils were added to hazelnut paste, the increment of stigmasta-3,5-diene allowed detection at levels of 2% oil added. Limits of detection were measured using standard and adulterated hazelnut with different amounts of non-refined vegetable oils added (5%, 10%, 20% and 30%). The distribution of tocopherols and tocotrienols is highly useful, except in the case of added sunflower oil. The differences between the experimental and theoretical values of the TAG with equivalent carbon number (ΔECN) of 42 does not improve the detection limit of hazelnut paste adulterated with peanut or sunflower oils. Similarly, tocopherols usually added to refined vegetable oils as an antioxidant were also determined.     

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。     

Effects of different nut oils on the structures and properties of gel-like emulsions induced by ultrasound using soy protein as an emulsifier

Gel-like emulsions were produced by high-intensity ultrasound (HIU) emulsification using soy protein as an emulsifier. Sunflower (a seed kernel oil), peanut (a groundnut oil), hazelnut, walnut, almond and pine nut oils were chosen as oil phases. The kinds of nut oil significantly affect the structures and properties of gel-like emulsions. The particle size of sunflower oil gel-like emulsion was smallest. Moreover, the macrorheological and microrheological results indicated that the values of apparent viscosity, storage modulus (G′) and elasticity index (EI) of sunflower and almond oil gel-like emulsions were higher while those of the walnut and pine nut oil gel-like emulsions were lower. Moreover, the sunflower oil gel-like emulsion was more stable after 2-month storage. The current study illustrated that HIU was of great importance for the production of high-viscosity gel-like emulsions. Furthermore, the differences of nut oils resulted in diverse physicochemical properties of gel-like emulsions.     

南瓜籽油中角鲨烯含量及特征指标比较

采用气相色谱、气相色谱-质谱和化学滴定法等手段,对我国不同产地的10个南瓜籽油的特征指标(碘值、皂化值、相对密度、折光指数、脂肪酸组成)和角鲨烯含量进行了分析,并和其他特种木本油脂中的角鲨烯含量进行比较。结果表明:南瓜籽油相对密度范围为0.9188~0.9215;折光指数为1.4560~1.4669;碘值为108.4~116.2 g/100 g;皂化值为188.9~192.4 mg/g;共检出14种脂肪酸成分,其中以亚油酸和油酸为主,亚油酸含量在44.7%~55.5%,油酸含量在23.8%~33.1%,10个南瓜籽油中不饱和脂肪酸含量均高于78.2%;南瓜籽油中角鲨烯含量较高(310~4446 mg/kg),与橄榄油相当,明显高于茶叶籽油、澳洲坚果油、核桃油、牛油果油等。综合考虑油脂色泽、角鲨烯含量和主成分分析结果,猜测角鲨烯含量差异较大的原因可能和油脂的制取工艺有关,部分南瓜籽油在深加工过程中损失了角鲨烯。南瓜籽油具有较高的营养价值,该研究对进一步挖掘南瓜籽开发应用前景,提高其综合利用价值提供了数据支撑。     

Molecular characterization of edible vegetable oils via free fatty acid and triacylglycerol fingerprints by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

Free fatty acids (FFAs) and triacylglycerols (TAGs) are the main components of edible vegetable oils. In this work, electrospray ionisation (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed to characterise the molecular composition of FFAs and TAGs in various vegetable oils, including soybean, rapeseed, corn, sunflower, peanut, linseed and olive oils. Semiquantitative analysis of FFAs and structural analysis of TAGs by MS/MS were further conducted to reveal the differences in the molecular compositions of the various vegetable oils. It was found that each vegetable oil has characteristic fingerprints of FFAs and TAGs. MS/MS measurements showed that the high-abundance TAGs in each vegetable oil were mainly composed of their abundant FFAs and glycerol. FFA and TAG fingerprints of genetically modified (GM) and nongenetically modified (non-GM) vegetable oils were similar, exhibiting only subtle differences, as confirmed by principal component analysis (PCA).     

Quantitative determination of the iodine values of unsaturated plant oils using infrared and Raman spectroscopy methods

Thirteen edible oils: sunflower, avocado, hemp, high-linolenic flax, low-linolenic flax, safflower, walnut, roasted sesame, rice, corn, rapeseed, pumpkin seed, and hazel were studied in this work. Their fatty acid composition, iodine, acidic, peroxide, and saponification values were determined. Infrared and Raman spectra of the oils were recorded in the range 400–3200 cm^?1. The integral intensities of the bands at about 1655 and 2852 cm^?1 corresponding to ν(C=C) and ν(CH₂) vibrations were evaluated and used to construct a relationship between the spectroscopic data and the iodine value. The following linear dependencies were obtained: I_ν(C=C)/I_ν(CH2) = 7.449 × 10^?4 × iodine value – 0.0339 and I_ν(C=C)/I_ν(CH2) = 9.299 × 10^?4 × iodine value – 0.023 for the infrared and Raman spectra with a correlation coefficient 0.988 and 0.976, respectively. These calibration lines can be used to determine the iodine value for oils with unknown unsaturation level, and may be applied for margarines and other fatty materials.     

Detection of sesame seed DNA in foods using real-time PCR

The detection of potentially allergenic foods, such as sesame seeds, in food products is a major concern for the food-processing industry. A real-time PCR method was designed to determine if sesame seed DNA is present in food products. The PCR reaction amplifies a 66-bp fragment of the sesame seed 2S albumin gene, which is detected with a sesame-specific, dual-labeled TaqMan probe. This reaction will not amplify DNA derived from other seeds present in baked goods, such as pumpkin, poppy, and sunflower seeds. Additionally, this assay will not cross-react with DNA from several tree nut species, such as almond, Brazil nut, cashew, hazelnut, and walnut, as well as four varieties of peanut. This assay is sensitive enough to detect 5 pg of purified sesame seed DNA, as well as sesame seed DNA in a spiked wheat cracker sample.     

Triglyceride species compositions of common edible vegetable oils and methods used for their identification and quantification

The chromatographic, spectrophotometric, and spectroscopic methods used for detection, identification, and quantification of the triglyceride (TG) species present in common edible vegetable oils are reviewed. The TG species identified in each kind of oil and their percentage distributions reported in literature are presented in tabular form. Data on oils from the following 10 sources are reviewed: corn, cottonseed, grapeseed, linseed, olive, palm, peanut, rapeseed, soybean, and sunflower. The number of TG species identified in these vegetable oils ranged from 20 (grapeseed oil (GR)) to 79 (peanut oil (PN)), with six (GR) to 13 (PN) different fatty acyl moieties contributing to their molecular structures. The quantitative levels reported ranged from traces (below 0.1%) to 49.7% (trilinolenin in linseed oil) and 54.6% (triolein in olive oil), respectively. The highest mean values (30-35%) correspond to four predominant TG species (dipalmitoylolein, trilinolein, trilinolenin, and triolein).     

Some of the most significant changes in the Fourier transform infrared spectra of edible oils under oxidative conditions

The oxidation of a broad collection of commercial edible oils, including extra virgin olive, olive, sesame, sunflower, corn, unknown seed, soybean, safflower, rapeseed, peanut and walnut oils, was monitored by Fourier transform infrared spectroscopy. Samples were kept in a convection oven with air circulating at 70 °C. Duplicate spectra were collected each day of the experiment by applying a film of pure oil between two KBr disks. The frequency and absorbance of each infrared band were automatically registered by a macro program. Ratios between absorbances of different bands of the spectra were calculated. Changes in frequency values of different bands and in ratios between absorbances of some bands allow different stages of the oxidation process to be distinguished as well as determining their oxidative stability in a simple and fast way, showing the usefulness of this technique in monitoring oil oxidation processes. © 2000 Society of Chemical Industry     

Analysis of volatile compounds in edible oils using simultaneous distillation-solvent extraction and direct coupling of liquid chromatography with gas chromatography

 Identification of volatile compounds in different edible oils (i.e. olive oil, almond oil, hazelnut oil, peanut oil and walnut oil) was performed using simultaneous distillation-solvent extraction followed by gas chromatographic-mass spectrometric analysis. An alternative approach which allows the direct injection of the oil sample (i.e. without any kind of pre-treatment) and involves the use of on-line coupled reversed phase liquid chromatography-gas chromatography (RPLC-GC) was also considered and the advantages of avoiding off-line preseparation for the analysis of volatile compounds were underlined regarding difficulties associated with the lipophilic nature of most volatile compounds and, hence, with the reliability of their analysis. Received: 14 June 1999 / Revised version: 3 August 1999     

Authentication of extra virgin olive oils by Fourier-transform infrared spectroscopy

Fourier-transform infrared spectroscopy (FTIR), followed by multivariate treatment of the spectral data, was used to classify vegetable oils according to their botanical origin, and also to establish the composition of binary mixtures of extra virgin olive oil (EVOO) with other low cost edible oils. Oil samples corresponding to five different botanical origins (EVOO, sunflower, corn, soybean and hazelnut) were used. The wavelength scale of the FTIR spectra of the oils was divided in 26 regions. The normalized absorbance peak areas within these regions were used as predictors. Classification of the oil samples according to their botanical origin was achieved by linear discriminant analysis (LDA). An excellent resolution among all categories was achieved using an LDA model constructed with eight predictors. In addition, multiple linear regression models were used to predict the composition of binary mixtures of EVOO with sunflower, corn, soybean and hazelnut oils. For all the binary mixtures, models capable of detecting a low cost oil content in EVOO as low as 5% were obtained.     

Correlation of fatty acid composition of vegetable oils with rheological behaviour and oil uptake

The fatty acid compositions of seven edible vegetable oils were investigated and correlated with their rheological behaviours and the amount of absorbed oils to fried products. All oil samples showed constant viscosity as a function of shear rate, exhibiting Newtonian behaviours. The highest viscosity was observed in hazelnut oil, followed by olive, canola, corn, soybean, sunflower, and grapeseed oils. In addition, a high correlation (R² = 0.94) demonstrated that the flow behaviours of vegetable oils were positively governed by their major components (18:1 and 18:2 fatty acids). It was also shown that a more rapid change in viscosity with temperature was observed in the oils containing more double bonds (R² = 0.71). Furthermore, even though the overall tendency was that the potato strips fried in the oils with high viscosity appeared to cause more oil uptake, a significant effect of oil types on oil uptake was not observed.     

蒙脱土对植物油脱色效果的综合评价北大核心CSCD

为了开发高效、环保的食用油脱色剂,以一种环保方法(半干法)生产的蒙脱土为研究对象,研究其在不同脱色条件(脱色温度、脱色时间和脱色剂添加量)下对大豆油、葵花籽油和菜籽油品质的影响。结果表明:该蒙脱土具有吸附色素和过氧化物从而降低油脂红值和过氧化值的作用,与脱色前相比,大豆油、葵花籽油和菜籽油的红值最大降幅分别为77.4%、92.3%和87.2%,过氧化值最大降幅分别为82.7%、83.2%和91.2%;蒙脱土用于3种植物油的脱色,植物油中总甾醇和总生育酚含量下降,而酸值总体上缓慢上升。进一步研究发现,在相同的脱色条件下,蒙脱土对大豆油、葵花籽油和菜籽油的酸值、总甾醇含量和吸油率的影响结果均优于活性白土,尤其是吸油率几乎是活性白土的一半。蒙脱土可替代活性白土用于对色泽要求不是很高的植物油脱色中。     

顶空固相微萃取-气相色谱-质谱联用法对食用植物油中易挥发成分的分析

采用顶空固相微萃取技术对7 种食用植物油（菜籽油、亚麻籽油、芝麻油、花生油、玉米胚芽油、葵花籽
油和大豆油）中易挥发成分进行萃取富集,然后采用气相色谱-质谱联用法对其化学组成进行分离及定性,共检测
出118 种化合物,其中包括：酸类、醛类、醇类、酮类、烃类、醚类、硫甙降解物、吡嗪类、呋喃类、芳香类、酚
类、吡咯类、吡啶类、吡喃类、噻唑类、酯类及其他类型化合物。并对各油种间主要易挥发成分的差异进行了分析
评价。     

The composition and concentration of n-alkanes in retail samples of edible oils

Abstract : A range of edible oils were purchased from a variety of retail outlets and analysed for their n-alkane (Σ33/15) content. The concentrations ranged from 7 to 166 mg kg^?1, the lowest being walnut oil and the highest sunflower oil. n-Alkanes with chain lengths of C₂₇, C₂₉ and C₃₁ predominated in all of the plant oils except olive oil where C₂₃, C₂₅ and C₂₇ were the most significant. The results of this pilot survey suggest that the n-alkanes are indigenous and that their composition may be useful in characterising a specific plant seed oil. Two of the 42 samples analysed showed markedly different alkane patterns in which profiles similar to petroleum-based sources dominated the contribution from odd carbon n-alkanes typical of seed 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。     

二维相关近红外光谱快速鉴别食用植物油种类

由于食用植物油中各种脂肪酸的组成基本相同或相近,仅存在含量分布的差异,因此食用植物油的一维近红外光谱图的峰位、峰形、峰强没有明显区别.利用傅里叶变换近红外光谱( FT - NIR)结合二维相关分析技术,分析鉴别了几种不同种类的食用植物油.对花生油、大豆油、菜籽油、芝麻油、油茶籽油和橄榄油,在温度挠动(50～160℃)状...     

Influence of hazelnut oil phospholipids on the skin moisturizing effect of a cosmetic emulsion

Previous studies have shown significant differences between the moisturizing effects and skin tolerances of virgin and refined vegetable oils when incorporated in cosmetic emulsions. They have also shown significantly greater and longer lasting moisturizing potential for a cosmetic emulsion containing virgin vegetable oils when compared with refined oils in the same emulsion. Results were obtained with sweet almond and hazelnut oils. Hazelnut oil has now been analysed to show the effect of refining. The phospholipid content of the oil decreased from 286 ppm in virgin oil to traces in refined oil.
These oils were added at 10% to a cosmetic emulsion applied twice a day for 28 days to the skin of 56 volunteers and the changes in moisturizing effect measured by means of the capacitance method (corneometer CM 240 Khazaka). Measurements were made under conditions of controlled temperature and humidity on the first day of application and repeated after 21 and 28 days of treatment. A significant increase in the moisturizing effect of the emulsion containing virgin hazelnut oil was found and this was itself significantly greater than the emulsion containing refined oil. Both emulsions had a greater moisturizing effect when compared with the control emulsion and the untreated skin.
Phospholipids were isolated by dialysis from virgin oil and added to the refined oil (234 ppm). The moisturizing effect obtained with the emulsion containing the enriched refined oil was shown to be the same as that obtained with the virgin oil emulsion.     

Production of omega 3, 6, and 9 fatty acids from hydrolysis of vegetable oils and animal fat with Colletotrichum gloeosporioides lipase

Food Science and Biotechnology - Hydrolysis of vegetable oils (Olive, corn, peanut, sesame, flaxseed, soy, canola, garlic, sunflower, almond, castor bean oils) and beef marrow bone oil by...     

Evaluating and Predicting the Oxidative Stability of Vegetable Oils with Different Fatty Acid Compositions

The aim of this research was to evaluate the oxidative stabilities and qualities of different vegetable oils (almond, blend 1‐8, camellia, corn, palm, peanut, rapeseed, sesame, soybean, sunflower, and zanthoxylum oil) based on peroxide value (PV), vitamin E content, free fatty acid, and fatty acid composition. The vegetable oils with different initial fatty acid compositions were studied under accelerated oxidation condition. It showed that PV and n‐3 polyunsaturated fatty acid (PUFA) changed significantly during 21 d accelerated oxidation storage. Based on the changes of PV and fatty acid composition during the oxidation process, mathematical models were hypothesized and the models were simulated by Matlab to generate the proposed equations. These equations were established on the basis of the different PUFA contents as 10% to 28%, 28% to 46%, and 46% to 64%, respectively. The simulated models were proven to be validated and valuable for assessing the degree of oxidation and predicting the shelf life of vegetable oils.