微波对植物油中维生素E抗氧化性能的作用

阐述维生素Ｅ结构的及其抗氧化机理，综述微波作用下植物油中维生素Ｅ抗氧化性能的变化。     

我国食用植物油维生素E含量研究

通过对中国市场上的13种食用植物油,包括100多个品牌,共326个样品的维生素E含量进行检测分析．采用的检测方法为AOCS Official Method Ce8-89方法,结果表明：各种食用植物油按总维生素E平均含量的从大到小的排列顺序为大豆油（105．91mg／100g）、玉米油（88．65mg／100g）、葵花籽油（74．45mg／100g）、菜籽油（69．37mg／100g）、芝麻油（51．66mg／100g）、葡萄籽油（42．35mg／100g）、花生油（42．12mg／100g）、亚麻籽油（37．71mg／100g）、红花籽油（32．91mg／100g）、米糠油（32．27mg／100g）、橄榄油（22．03mg／100g）、核桃油（20．94mg／~OOg）、茶籽油（12．78mg／100g）。     

食用植物油掺入矿物油的鉴别

重点叙述食用植物油掺（混）入矿物油食用后对人体的危害,所引发的食物中毒案例以及对矿物油的鉴别检验方法。     

反相高效液相色谱法快速测定植物油中的维生素E

建立了快速测定植物油中维生素E含量的高效液相色谱法。采用VP-ODSC18色谱柱,流动相为甲醇/水(体积比为98∶2),流速为1ml/min,柱温为35℃,荧光检测激发波长为290nm,发射波长为340nm。在上述实验条件下,维生素E的线性范围为0.1～25mg/kg,检出限为2.7×10-2mg/kg,回收率为87.2%～97.3%,RSD为2.6%。该法测定样品,快速准确,重复性好。     

HPLC法同时测定植物油中维生素A和不同构型维生素E含量

以石油醚为溶剂,用索氏提取法提取了黑芝麻、白花生、黑花生、葵花籽、大豆、棉花籽的油脂。油样品先用正己烷溶解,然后用甲醇定容,其中正己烷含量为20%(v/v),用Hypersil ODS2 5μm色谱柱,甲醇为流动相,对所提油脂中维生素A、α-维生素E、γ-(β)维生素E、δ-维生素E含量进行检测。实验结果表明,在204nm波长下,维生素A、α-维生素E、γ-(β)维生素E、δ-维生素E在0~200μg/m L范围内与峰面积有良好的线性关系,标准曲线相关系数r均大于0.9978。维生素A、α-维生素E、γ-(β)维生素E、δ-维生素E加标平均回收率分别为97.83%、98.58%、98.75%、99.93%。     

HPLC法同时测定植物油中维生素A和不同构型维生素E含量

以石油醚为溶剂,用索氏提取法提取了黑芝麻、白花生、黑花生、葵花籽、大豆、棉花籽的油脂。油样品先用正己烷溶解,然后用甲醇定容,其中正己烷含量为20%（v/v）,用Hypersil ODS2 5μm色谱柱,甲醇为流动相,对所提油脂中维生素A、α-维生素E、γ-（β）维生素E、δ-维生素E含量进行检测。实验结果表明,在204nm波长下,维生素A、α-维生素E、γ-（β）维生素E、δ-维生素E在0²00μg/m L范围内与峰面积有良好的线性关系,标准曲线相关系数r均大于0.9978。维生素A、α-维生素E、γ-（β）维生素E、δ-维生素E加标平均回收率分别为97.83%、98.58%、98.75%、99.93%。      

微波辐射下植物油中维生素E抗氧化性能的变化

在阐述维生素Ｅ的抗氧化机理的基础上，重点综述了微波辐射作用下植物油中维生素Ｅ抗氧化性能的变化情况，并讨论了将来的研究方向     

常见食用植物油中维生素E异构体含量调查研究

通过查阅国内外官方食物成分数据库,同时综合近年来国内对成品食用植物油中不同生育酚和生育三烯酚含量进行分析的文献,建立常见食用植物油维生素E异构体成分表。结果表明:国内外现有数据库中食用植物油种类及其生育酚和生育三烯酚数据均不全,且不同地区含量存在明显差异。通过对国内最新研究汇总,共收集22种合计659个常见食用植物油的α-、β-、γ-、δ-生育酚数据,同时收集17种合计183个食用植物油的α-、(β+γ)-、δ-生育三烯酚数据。生育酚广泛存在于植物油中,以α-生育酚和γ-生育酚为主,但不同植物油中含量情况存在明显差异;生育三烯酚主要存在于棕榈油、米糠油和葡萄籽油中,在其他植物油中分布很少。不同类型食用植物油的选择会明显影响人体活性VE总量和不同异构体的摄入情况,目前国内外食用植物油VE异构体数据库有地区差异且均不能覆盖目前常见的食用植物油种类,更新常见成品食用植物油VE数据库很有必要。     

高效液相色谱法同时测定植物油中3种维生素A和9种维生素E

建立1种通过高效液相色谱法同时测定植物油中3种维生素A(维生素A-全反式酯、维生素A-醋酸酯、维生素A-棕榈酸酯)和9种维生素E(δ-生育三稀酚、β-生育三稀酚、γ-生育三稀酚、α-生育三稀酚、δ-生育酚、β-生育酚、γ-生育酚、α-生育酚、d-α-醋酸酯)的方法,并对13种植物油进行检测。结果表明：方法的色谱柱为CAPCELL PAK PFP(150 mm×4.6 mm, 5μm)、提取剂为乙醇、2,6-二叔丁基对甲酚(BHT)添加量为0.01g、流动相为乙醇-水,梯度洗脱。建立的方法在质量浓度0.5～20μg/mL范围内,线性关系良好(R²> 0.999),方法的检出限为0.100～2.80 mg/kg、定量限为0.332～13.32 mg/kg、相对标准偏差(RSD)≤5.27%、回收率为80.67%～98.42%。建立的方法可用于植物油中3种维生素A和9种维生素E的同时检测。     

Authentication of edible vegetable oils adulterated with used frying oil by Fourier Transform Infrared Spectroscopy

The application of Fourier Transform Infrared (FTIR) Spectroscopy to authenticate edible vegetable oils (corn, peanut, rapeseed and soybean oil) adulterated with used frying oil was introduced in this paper. The FTIR spectrum of oil was divided into 22 regions which corresponded to the constituents and molecular structures of vegetable oils. Samples of calibration set were classified into four categories for corn and peanut oils and five categories for rapeseed and soybean oils by cluster analysis. Qualitative analysis of validation set was obtained by discriminant analysis. Area ratio between absorption band 19 and 20 and wavenumber shift of band 19 were treated by linear regression for quantitative analysis. For four adulteration types, LODs of area ratio were 6.6%, 7.2%, 5.5%, 3.6% and wavenumber shift were 8.1%, 9.0%, 6.9%, 5.6%, respectively. The proposed methodology is a useful tool to authenticate the edible vegetable oils adulterated with used frying oil.     

Discrimination of olive oil adulterated with vegetable oils using dielectric spectroscopy

The study focused on application of dielectric spectroscopy to identify the adulteration of olive oil. The dielectric properties of binary mixture of oils were investigated in the frequency range of 101 Hz–1 MHz. A partial least squares (PLS) model was developed and used to verify the concentrations of the adulterant. Furthermore, the principal component analysis (PCA) was used to classify olive oil sample as distinct from other adulterants based on their dielectric spectra. The results showed that the dielectric spectra of binary mixture of olive oil spiked with other oils increased with increasing concentration of soy, corn, canola, sesame, and perilla oils from 0% to 100% (w/w) over the measured frequency range. PLS calibration model showed a good prediction capability for the concentrations of the adulterant. For olive oil adulterated with soy oil, the results showed that the RMS was 0.053, sd(RMS), 0.017 and Q² value was 0.967. PCA classification plots for all oil samples showed clear performance in the differentiation for the different concentrations of the adulterant. Each of the oil samples could be easily grouped in different clusters using dielectric spectra. From the results obtained in this research, dielectric spectroscopy could be used to discriminate the olive oil adulterated with the different types of the oils at levels of adulteration below 5%.     

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.     

芝麻油掺棕榈油鉴别方法的研究

以4种不同熔点棕榈油与4种芝麻油所配制的128个掺伪芝麻油样品为原料,分别采用全样脂肪酸组成分析法、Sn-2位脂肪酸组成分析法和甘三酯结构分析法对芝麻油中掺棕榈油的鉴别方法进行了研究。结果表明:在全样脂肪酸组成分析法中,当以棕榈酸为标准与芝麻油纯样和国标数据比较时,检出限分别为5%和15%。在Sn-2位脂肪酸组成分析法和甘三酯结构分析法中,当与芝麻油纯样数据比较,分别以亚油酸与棕榈酸含量比值(18:2/16:0)和β-POO(Sn-1-棕榈酸-2,3-二油酸甘油酯)含量为判断标准时,检出限分别为20%和12%。综合这3种方法的检出限高低及分析操作难易程度,初步得出结论:在芝麻油掺棕榈油的鉴别方法中,全样脂肪酸组成分析法是最好的鉴别方法,其余2种方法一般不优先采用,但可作为对上述方法的验证与补充。     

Heat-oxidation stability of palm oil blended with extra virgin olive oil

Rancimat induction time of palm oil (PO), several extra virgin olive oils (EV) and their binary blends have been determined at three different temperatures (120, 130 and 140°C). Analytical composition and oxidation stability of PO/EV blends were found to be a linear combination of the oil partners. Induction time of pure PO was always higher than those of EV oils and blends, in which induction time increased proportionally with the percentage of PO. However, induction time of 80% PO blend was similar to that of pure PO. Fatty acid composition appeared to be the most important factor affecting heat-oxidation stability and a saturated/unsaturated ratio near 1 was the optimally stable composition. Conversely, total phenols had a zero or negative role on the oxidative stability of the blends. Finally, in heat-oxidised oils significant losses of polyunsaturated fatty acids and formation of short-chain fatty acids were recorded.     

Detection of olive oil adulteration with some plant oils by GLC analysis of sterols using polar column

A new method was developed to determine the presence of some refined vegetable oils in olive oil based on the sum of campesterol and stigmasterol percentages. Model systems of corn, soybean, sunflower and cotton seed oils in olive oil at levels of 5%, 10% and 20% were prepared. The unsaponifiables of these model systems were analysed by GLC using polar column with high thermal stability. An olive oil authenticity factor based on the summation of campesterol and stigmasterol percentages was established as an indicator of olive oil adulteration with vegetable oils. The results indicate the possibility to detect the presence as little as 5% of these plant oils in olive oil.     

芝麻油中掺棉籽油的分光光度法研究

研究了用分光光度法测定麻油的掺假情况，该方法具有操作简单，准确度高等特点，可以定量测定芝麻油的纯度。并对4种掺假芝麻油样品进行了检验验证，其变异系数均小于5％。     

不同食用植物油中维生素E组分及含量研究

通过对9个不同品种的138个食用植物油样品中维生素E组分及含量的测定,分析研究不同食用植物油中维生素E组分及含量的分布情况。结果表明:9个油脂品种、101个一级油样品中维生素E含量范围为5.9~1 246.6 mg/kg,平均值652.4 mg/kg,维生素E总量的平均值排序为大豆油棉籽油玉米油葵花籽油菜籽油米糠油花生油芝麻油山茶油;不同油脂样品中维生素E的组分有明显差别,米糠油含有最齐全的8种维生素E组分,并且生育三烯酚含量的平均值占维生素E总量平均值的44.2%;玉米油含有3种生育酚和2种生育三烯酚,棉籽油中含有3种生育酚和1种生育三烯酚,但这两种油脂中生育三烯酚含量平均值分别仅占维生素E总量平均值的5.8%和2.8%;大豆油、菜籽油、花生油、葵花籽油均含有α-、γ-、δ-生育酚3种组分;山茶油中含有α-、γ-生育酚2种组分;芝麻油仅含有γ-生育酚1种组分。除芝麻油之外,所有油脂中均含有α-生育酚和γ-生育酚,其中葵花籽油中α-生育酚含量最高,大豆油中γ-生育酚含量最高。同一油脂品种、不同等级的油脂中维生素E含量也存在差异,总体趋势是维生素E含量随油脂精炼程度的加深而降低,但个别二级菜籽油样品中维生素E含量低于一级菜籽油,这与所采集油脂样品的来源不同有关。不同油脂品种、不同等级的食用植物油中维生素E组分及含量因油料品种、油脂精炼工艺的不同显示出明显差异。     

高效液相色谱法同时测定食用油中维生素A和E的方法

本文建立了高效液相色谱法同时测定食用油中维生素A和4种维生素E生育酚的方法。利用维生素A醋酸酯和维生素E生育酚分别在325nm和294nm的波长下的吸收特性。以液相色谱紫外检测器双波长的方式,考察研究处理方式并开发同时检测食用油中维生素A和E的方法。通过该方法结果表明：维生素A的精密度RSD为0.84%~1.39%,回收率范围在95.8%~104.4%;维生素E的各生育酚组分精密度RSD为2.01%~4.14%,回收率范围在96.2%~112%。本方法也可应用于测定不同食用油中维生素A和E且有效可靠。测得葵花籽油维生素A含量735.58±3.86 μg/100g,维生素E(α-TE)的含量为54.33±2.92 mg/100g;玉米油维生素A含量676.75±2.15 μg/100g,维生素E(α-TE)的含量为24.78±1.36 mg/100g。通过方法验证,确认液相色谱同时检测维生素A和E的方法用于食用油中有效可靠。