Effect of Tocopherol on Antioxygenic Properties of Green Lubricating Oil

Based on the needs of green motor oil, and in order to improve the antioxidation properties of green lubricating oil, the effect of tocopherol antioxidation properties of rapeseed oil was studied. Experiments of high temperature oxidation, antiwear and infra-red spectrum analysis were accomplished, the results show that the rapeseed oil including tocopherol can still keeps steady structure after high temperature oxidation, with a small variety of acid number, whose antioxygenic properties are improved evidently. Meanwhile, both thiocarbamate and vitamin C play an assistant role in tocopherol, which can make rapeseed oil to have better oxidation stability and keep excellent antiwear properties after high temperature oxidation.

A Methodological Approach to Study Almond Oil Stability in Relation to <i>α</i>-Tocopherol Supplementation

The objectives of the present study were to identify a suitable parameter to assess the oil oxidation and to study the possibilities of delaying the oxidation of moderately oxidized unrefined almond oil by adding supplementary amounts of α-tocopherol. Three oil samples, with initial peroxide values of 13.3, 19.5 (moderately oxidized oils), and 28.9 (oxidized oil), were supplemented with 100, 250 and 500 ppm of α-tocopherol and subjected to the oxidation at 50°C for 9 days. The level of oxidation was determined by measuring peroxide value (PV), conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS). Chemometric analysis indicated that, under the conditions of the present study, PV was the most suitable indicator of oil oxidation. The results have shown that the α-tocopherol could have an anti- oxidant or pro-oxidant effects, depending on its concentration and initial level of oil oxidation. Results also show that α-tocopherol addition at all the concentrations tested resulted in pro-oxidation of the moderately oxidized oils;hence additional supplementation with α-tocopherol could not be recommended to delay oxidation of unrefined almond oil.

Comparison of the Physicochemical Characteristics of Pinus koraiensis L. Nut Oils from Different Extraction Technologies

In this study, the physicochemical properties, fatty acid profiles, and tocopherol compositions of Pinus koraiensis L.nut oils were evaluated, and the impact of different extraction technologies on the overall quality of pine nut oil was assessed. All the pine nut oils had pleasant and characteristic odor and flavor of the pine nuts and the flavor of the oil from hot-pressing was strongest. The oils obtained by hexane extraction and sub-critical extraction had less deterioration, indicating hexane extraction and sub-critical extraction preserve the oil quality well. Gas chromatography showed that the predominant fatty acid was linoleic acid(45.36%–45.91%), followed by oleic acid(26.91%–27.10%), and pinolenic acid(13.33%–13.63%), respectively. The oils from hexane extraction of cold-pressed cake and sub-critical extraction were richer in tocopherols and tocotrienols, namely, 37.52 and 36.18 mg/100 g, respectively, with α-tocopherol most abundant. The pine nut oils from hexane extraction of cold-pressed cake,hexane extraction, cold pressing, and sub-critical extraction had better oxidation stability with the oxidation induction times of 6.91, 5.27, 4.96 and 4.93 h, respectively. Based on its features, P. koraiensis nut oil may have the multiple application in edible oil, cosmetic, and pharmaceutical industry. P. koraiensis can be one of the good woody candidates for closing the gap between the demand and production of vegetable oils.

Effects of Red Palm Oil on Serum Lipids and Plasma Carotenoids Level in Chinese Male Adults

Objective Effects of red palm oil on major plasma carotenoids, tocopherol, retinol and serum lipids were evaluated when used in Chinese diet. Methods Red palm oil group (RPO) composed of 20 male subjects(aged 18-32) and soybean oil group (SBO) composed of 22 male subjects (aged 18-32). Dietary fat provided about 28% of total calories, and the test oil accounted for about 60% of total dietary fat. In the 3 weeks of pretest period, diets were prepared with soybean oil, and then in the next 6 weeks subjects in each group consumed the diet prepared by test oil. Results Plasma α-carotene, β-carotene and lycopene concentration of RPO group significantly increased at the time of interim (21 days) and of the end (42 days) (P<0.05), and α-tocopherol concentration significantly increased at the time of the end (42 days) in this study. Though Chinese plasma retinol level was relatively low when compared with that of Westerners, red palm oil diet showed no significant effect on adult Chinese plasma retinol level. Serum concentration of total cholesterol, triglyceride, high density lipoprotein cholesterol, apolipoprotein AI and apolipoprotein B of all subjects showed no significant changes in RPO group during the study. Conclusions The data in our study suggest that red palm oil is a good source of carotenoids and vitamin E when used in Chinese diet preparation, and it can significantly increase plasma concentration of a-carotene, α-carotene, lycopene and β-tocopherol.

复配抗氧化剂在牡丹籽油乳液中的抗氧化作用研究

为提高牡丹籽油乳液的氧化稳定性,将叔丁基对苯二酚(TBHQ)与天然抗氧化剂(生育酚、抗坏血酸)进行复配,测定不同抗氧化剂对牡丹籽油乳液的抗氧化作用,并分析了不同复配抗氧化剂的相互作用机制。结果表明:在贮藏30 d时,添加和未添加抗氧化剂牡丹籽油乳液的粒径相较于0 d均略有增加,200 mg/kg TBHQ与800 mg/kg抗坏血酸复配时乳液的Zeta电位绝对值最大,且抗氧化作用最强;TBHQ与抗坏血酸表现出较好的协同抗氧化作用,与生育酚表现出拮抗作用;TBHQ与生育酚之间拮抗作用的原因主要是TBHQ减少了生育酚在牡丹籽油乳液中油水界面的含量,而TBHQ与抗坏血酸之间协同作用主要是由于抗坏血酸增加了TBHQ在牡丹籽油乳液中油水界面的含量。综上,TBHQ与抗坏血酸复配能提高牡丹籽油乳液的氧化稳定性。

精炼过程中大豆油及其脱臭馏出物中生育酚的变化

旨在为大豆油的精准适度加工以保留微量营养成分提供参考,对巴西和美国大豆原油、中和油、脱色油、脱臭油、脱臭馏出物的生育酚含量及其异构体占比进行了分析,探讨和研究生育酚在精炼各工段的变化及生育酚异构体的占比规律。结果表明:大豆油中生育酚在精炼各工段均有损失,脱臭工段损失最多,生育酚和α-、γ-、δ-生育酚异构体损失率分别为11.68%~19.37%、6.10%~17.64%、11.56%~19.68%、17.29%~25.51%,在脱臭和整个精炼过程中3种生育酚异构体的损失率均表现为δ-生育酚>γ-生育酚>α-生育酚;与原油相比较,精炼后大豆油中α-、γ-生育酚占比分别增加了0.4~2.1百分点和0.1~1.2百分点,δ-生育酚占比减少了1.3~2.7百分点,说明大豆油中的δ-生育酚更容易被高温分解或挥发而被汽提蒸汽夹带进脱臭馏出物中;美国大豆原油酸值(KOH)在1.5 mg/g以下,其脱臭馏出物中生育酚含量在97419~109123 mg/kg,为原油的80~89倍,巴西大豆原油酸值(KOH)在1.5~3.3 mg/g,其脱臭馏出物中生育酚含量在34678~83803 mg/kg,为原油的59~84倍,美国和巴西的大豆油脱臭馏出物中α-、γ-、δ-生育酚占比分别为6.5%~9.3%、61.0%~62.4%、26.7%~31.4%和8.4%~9.9%,58.0~61.8%,28.0%~30.4%,与对应脱臭油相比较,美国和巴西的大豆油脱臭馏出物中α-、γ-生育酚占比分别减少了0.1~2.5百分点、4.5~6.7百分点和0.5~2.9百分点、2.9~6.9百分点,δ-生育酚占比分别增加了5.5~8.2百分点和5.6~7.8百分点,说明脱臭工段生育酚因挥发而被汽提蒸汽夹带的速率大小为δ-生育酚>α-生育酚>γ-生育酚。因此,应该优化脱臭工段的工艺条件,以最大程度避免生育酚的过度损失。

GC-MS/MS测定植物油中生育酚和生育三烯酚

建立一种气相色谱-串联质谱法(GC-MS/MS)同时测定植物油中α-、β-、γ-、δ-生育酚和α-、β-、γ-、δ-生育三烯酚含量的方法。样品经异辛烷超声提取后,采用动态多反应监测离子模式分析。结果表明:8种维生素E异构体可实现基线分离,在1~500 ng/mL范围内,线性关系良好,相关系数均大于0.999,检出限和定量限分别为0.02~0.05 mg/kg和0.10 mg/kg,平均回收率为81.5%~109.5%,相对标准偏差为3.3%~7.2%。方法快速、简便、准确、灵敏度高,适用于植物油中生育酚和生育三烯酚含量的测定。

基于液相色谱法对不同种类植物油中微量营养成分的测定与分析

建立了高效液相色谱法测定不同类型植物油中乌发醇、菜油甾醇、岩藻甾醇、菜籽甾醇、豆甾醇、麦角甾醇、环阿屯醇、β-谷甾醇、角鲨烯的方法,同时采用GB 5009.82-2016《食品中维生素A、D、E的测定》中的第一法(荧光检测器)对植物油中的维生素E进行了测定。结果表明:9种微量营养成分线性良好,检出限范围为0.3~4.0 mg/kg,定量限范围为1~12 mg/kg;加标回收率为69.3%~117.2%,RSD范围为0.71%~6.83%。7种不同类型植物油中均含有β-谷甾醇、菜油甾醇、乌发醇、角鲨烯、α-生育酚、β-生育酚、γ-生育酚、δ-生育酚,其含量各有不同。通过对不同种类植物油中植物甾醇、角鲨烯、维生素E的测定和分析,深入挖掘不同种类植物油中各自的特征成分和含量差异,提升其品牌影响力。

杏仁皮油营养品质及组成分析

目的系统评价杏仁皮油营养品质及组成。方法采用气相色谱仪、高效液相色谱仪及气相色谱-质谱联用仪分析杏仁皮油的甘油三酯组成、sn-2脂肪酸分布及微量组分含量。结果杏仁皮油中甘油三酯主要为LLO,其sn-2位脂肪酸主要为亚油酸与油酸;杏仁皮油中植物甾醇含量为1027.49 mg/kg,生育酚含量为337.35 mg/kg,角鲨烯含量为22.47 mg/kg,多酚含量为15.33 mg/kg。结论杏仁皮油属于高品质的植物油。

反相高效液相色谱法同时测定植物油中四种生育酚

建立了反相液相色谱法同时测定植物油中4种生育酚的方法。样品用甲醇超声提取,离心后取上清液氮吹至干,甲醇定容后过有机相滤膜,反相C30柱(4.6 mm i.d.×250 mm,5μm)分离,甲醇-水-叔丁基甲醚(60∶15∶25)作流动相等度洗脱,荧光检测(λex=290 nm,λem=340 nm)。结果表明,4种生育酚的质量浓度在0.050～100.0 mg/L范围内与峰面积呈良好的线性关系,线性相关系数(r2)大于0.999。在加标水平为0.50、50.0、500.0 mg/kg时,4种生育酚的平均加标回收率为81.3%～93.2%,相对标准偏差(RSD)小于6%,α-生育酚、β-生育酚、γ-生育酚及δ-生育酚的方法检出限(LOD)分别为0.10、0.05、0.05、0.02mg/kg。方法准确、灵敏、可靠,可应用于实际样品的分析。

番茄红素在油脂氧化时的稳定性初探

对番茄红素在大豆色拉油和猪油光敏氧化过程中的稳定性进行了研究。将8、12、20×10-6浓度的番茄红素分别添加于大豆色拉油和猪油中,32℃时,在光照条件下,在亚甲基蓝试剂的引发下,其自身随着光照时间的延长,其残存率逐渐降低,稳定性下降;番茄红素在豆油中的氧化稳定性好于在猪油中的氧化稳定性;添加25、80×10-6的α-生育酚于大豆色拉油和猪油中,两种浓度均能明显增加番茄红素在猪油光敏氧化中的稳定性,使其残存率明显增加;但不能增加番茄红素在大豆色拉油光敏氧化过程中的稳定性。

应用校正变换矩阵法识别掺伪食用油

根据食用油中脂肪酸、甾醇以及生育酚含量 ,应用校正转换矩阵法对花生油掺伪进行了定量检测。用所建立的校正模型对棕榈油、菜籽油和棉籽油掺入到花生油所得到的27个二元和6个四元人工合成样品进行了验证 ,结果令人满意。对从市场上购得的5种花生油进行了测定 ,其中一种是由菜籽油假冒的花生油 ,另一种为掺入花生精油的棕榈油。

棕榈油中生育酚和生育三烯酚的HPLC测定

建立了棕榈油中生育酚和生育三烯酚的准确、快速的HPLC分析方法。选用Nucleosil硅胶柱正相分离,以正己烷-异丙醇为流动相,梯度洗脱,在紫外波长292nm下进行检测,获得较理想的分离效果。该方法线性范围为0.2275～1.3031mg/mL,平均加样回收率为100.17%,RSD=0.5905%。

食用植物油中生育酚含量测定方法优化及分析

采用高效液相色谱法测定了8种24个植物油样本中生育酚的含量,并对生育酚的提取条件进行优化。在室温下,以甲醇为溶剂,采用超声法进行提取,料液比为1：1.25,提取3次,每次20min,采用液相色谱方法进行分析。结果表明：该方法在生育酚质量浓度为0.05 ~ 1.00 g/ L时,相关系数 R2可达到0.999 2 ~0.999 4,线性关系良好;检出限分别为α-生育酚0.5 mg/ L,γ-生育酚2.0mg/ L,δ-生育酚1.2 mg/ L;三水平加标样品的平均回收率为92.1% ~99.8%,相对标准偏差（RSD,n=3）为2.5% ~8.5%。在8种植物油中,葵花籽油中α-生育酚的质量分数较高,可达4.2349×10-4,大豆油的β/γ-生育酚、δ-生育酚及总生育酚的质量分数较高,分别为7.3713×10-4 ,1.6215×10-4,9.8836×10-4。

多环芳烃脱除方法及其在维生素 E 油中的应用

介绍了多环芳烃(PAHs)的性质、来源和危害，详述了油、污水、土壤中多环芳烃的脱除方法：物理法(包括萃取法、吸附法、层析法及人造纤维富集法等)、化学反应法、生物反应法、化学-生物降解法等，比较了各种脱除方法的优缺点。分析了维生素E油中的PAHs的来源。实验结果显示，硅胶柱层析法、微波萃取法、人造纤维bluerayon吸附等方法对维生素E油中PAHs的脱除有较好的效果。

高效液相色谱-荧光检测法快速测定植物油中的α-生育酚

建立了快速测定植物油中α-生育酚含量的高效液相色谱法。采用VP-ODS C18色谱柱,流动相为甲醇/水(体积比为98∶2),流速为1 mL/min,柱温为35℃,荧光检测激发波长为290nm,发射波长为340 nm。在上述实验条件下,α-生育酚的线性范围为0.1-25 mg/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。

生育酚及甾醇含量对大豆油氧化稳定性及贮藏稳定性的影响

植物油是生育酚、甾醇等活性物质的最主要的膳食来源之一,但现有的过度精炼的工艺造成了生育酚和甾醇的大量损失,大大降低了食用植物油的营养价值。随着人们对营养健康的日益关注,加上行业内对植物油适度精炼工艺的号召,需要提高精炼后植物油中生育酚、甾醇的保留量,但植物油中生育酚和甾醇的最低含量的确定缺乏基础研究依据。因此,本文分别利用Rancimat法和Schaal烘箱法比较了不同生育酚及甾醇含量的大豆油的氧化稳定性和贮藏稳定性的差异,结果表明,生育酚和甾醇能够显著提高大豆油贮藏过程中的稳定性,但并不是剂量越高效果越强。当大豆油中生育酚及甾醇分别保留至0.12%、0.35%时,大豆油的氧化稳定性最强;当大豆油中生育酚及甾醇分别保留至0.12%、1.29%时,大豆油的贮藏稳定性最佳。本研究结果为植物油适度精炼工艺中相应产品标准(草案)的制修定提供基础数据,为探究以营养物质含量高低作为植物油新分级指标之一的可行性提供借鉴。

多环芳烃脱除方法及其在维生素E油中的应用

文章简要介绍了多环芳烃的性质、来源和危害,以及油、污水、土壤中多环芳烃的脱除方法,如:物理富集法、化学反应法、生物反应法、超临界流体萃取法等。文章比较了各种脱除方法的优缺点,分析了维生素E油中苯并芘的来源。试验表明,采用硅胶柱层析法、微波萃取法、人造纤维bluerayon富集法等均能达到脱除苯并芘的效果。

大豆油精炼过程中生育酚的损失

以国内21家大型油脂精炼厂生产的大豆油为对象,研究了精炼过程中生育酚总量和各单体含量的变化,重点考察了不同脱臭塔设备及脱臭条件与生育酚损失率之间的关系。结果表明,在油厂现有通用精炼条件下,整个精炼过程中生育酚总损失率不超过33%,4种生育酚单体(α,β,γ,δ)的相对比例几乎没有变化。影响生育酚保留率的关键因素为脱臭阶段塔的结构、温度及搅拌蒸汽用量。

正相超高压液相色谱法测定植物油中的维生素E

采用正相超高压液相色谱法测定油脂中4种常见生育酚的含量,确定一种简单、准确、快速测定维生素E的测定方法。样品经前处理后,用Zorbax RX-SIL硅胶柱分离,以乙酸乙酯-异辛烷为流动相梯度洗脱,在波长295 nm采用外标法检测α、β、γ、δ等四种生育酚在不同植物油中的含量。研究结果表明,该方法四种异构体均在8 min内出峰,线性关系在0.999 4～0.999 9间,精密度RSD<5%,加标回收率在80%～100%,线性范围0.2～100.0μg/mL,α、β、γ、δ异构体方法检出限均在0.01μg/g左右;几种典型植物油样品验证实验表明该方法体系具有快速、准确、分离度好等特点。同时比较了调和油和精炼地沟油维生素E含量差异,初步确定α-维生素E可能作为该类地沟油识别因子。