化学计量法结合气相色谱检测米糠油掺伪棉籽油

为研究米糠油掺混棉籽油的快速定性定量检测方法,采用毛细管气相色谱法测定米糠油掺不同比例棉籽油的脂肪酸含量。将C10∶0、C14∶0、C16∶0、C16∶1、C17∶0、C18∶0、C18∶1、C18∶2、C18∶3、C20∶0、C20∶1、C22∶1的含量作为变量,聚类分析结果表明米糠油掺棉籽油5%以上能正确进行辨别,判别分析结果表明米糠油掺棉籽油20%以上能进行正确辨别,建立了基于特征脂肪酸变化的掺伪量计算一元线性模型YC14∶0=0.004X+0.3168(R2=0.9813),及基于指纹图谱相似度的掺伪量计算模型Y=-240.52X5+677.8X4-697.92X3+312.09X2-66.998X+99.97(R2=0.9993)。方法重复性好,准确度高,误差5%以下。     

化学计量法结合气相色谱检测稻米油掺伪大豆油

为研究稻米油掺混大豆油的的快速检测方法,采用毛细管气相色谱法测定稻米油掺不同比例大豆油的脂肪酸含量,将C14∶0、C16∶0、C16∶1、C17∶0、C18∶0、C18∶1、C18∶2、C18∶3、C20∶0、C20∶1、C22∶0的含量作为变量,使用聚类分析和判别分析对掺伪油脂进行定性,结果表明,稻米油掺大豆油16%以上聚类分析能正确进行辨别,掺大豆油6%以上判别分析能正确进行辨别。建立大豆油定量检测的线性模型为YC18∶3=0.090 6 X+2.456 4(R2=0.992 5),利用向量夹角余弦法计算纯稻米油与掺伪稻米油的相似度,建立了掺伪量与相似度的线性模型,Y=12.33 X3-26.047 X2-2.685 5 X+100.05(R2=0.999 1)。     

米糠油指纹图谱的构建及掺伪定量检测技术研究

为完善米糠油掺伪的定量检测系统,采用恒温毛细管气相色谱法建立了米糠油指纹图谱,对米糠油进行模拟掺伪,建立了米糠油中廉价油脂掺伪量与特征脂肪酸含量的一元线性模型。结果表明:掺伪棕榈油最佳线性模型为YC16∶0=16.719X+18.722(R2=0.993 7);掺伪菜籽油最佳线性模型为YC22∶1=0.158 2X+0.350 7(R2=0.991 0),菜籽油掺伪量2%以上适用;掺伪棉籽油最佳线性模型为YC14∶0=0.004X+0.316 8(R2=0.981 3),棉籽油掺伪量17%以上适用;掺伪大豆油最佳线性模型为YC18∶3=0.090 6X+2.456 4(R2=0.992 5),大豆油掺伪量24%以上适用。     

基于指纹图谱相似度的米糠油掺伪检测方法研究

为快速准确对掺伪米糠油进行定量检测,将棕榈油、棉籽油、菜籽油、大豆油掺入纯米糠油,气相色谱法测定C10∶0、C14∶0、C16∶0、C16∶1、C18∶0、C18∶0、C18∶1、C18∶1、C18∶2、C18∶3、C20∶0、C20∶1、C22∶0、C22∶1的含量,利用向量夹角余弦法计算纯米糠油与掺伪米糠油的相似度,建立了掺伪量与相似度的线性模型.米糠油掺混棕榈油,计算模型为y =5.802 3x3-17.469x2-0.269 2x +99.99(R2 =0.999 6).米糠油掺混菜籽油,计算模型为y=-23.62x3-8.380 6x2-6.138 3x+ 100.12(R2=0.999 4).米糠油掺混棉籽油,计算模型为y=-240.52x5+ 677.8x4-697.92x3+ 312.09x2-66.998x+ 99.97(R2=0.999 3).米糠油掺混大豆油,计算模型为y=12.33x3-26.047x2-2.6855x+100.05(R2=0.999 1).     

食用油脂气相色谱指纹图谱分析

为了对近年来国内外市场的食用油脂进行营养评价,对掺假油脂进行科学的定性定量检测,采用毛细管气相色谱法对米糠油、茶籽油、棕榈油、花生油、大豆油、棉籽油、菜籽油、反复油炸菜籽油、泔水油、劣质动物油等进行分析。建立了各类油脂的色谱指纹图谱,得出了油脂的指纹图谱相似度,各油脂其脂肪酸C10∶0、C14∶0、C16∶0、C16∶1、C17∶0、C18∶0、C18∶1、C18∶2、C18∶3、C20∶0、C20∶1、C22∶0、22∶1含量及比例特性明显,可以利用油脂脂肪酸特点及指纹图谱相似度进行油脂的掺伪甄别检测。     

菜籽油脂肪酸组成特征指标及大豆油掺伪后不合格判定的研究

对2011年至2013年全国592份油菜籽样品和我站近年来检测菜籽油的数据进行汇总分析。当菜籽油中掺入不同比列的大豆油时,采用气相色谱法与植物油油脂定性试验进行检测,比较气相色谱组分分析法与油脂定性试验的化学法的差异性,并对是否符合菜籽油脂肪酸组成进行判定。结果表明:从油菜籽提油脂肪酸组成数据分析得到:特征1:芥酸(C22∶1)与油酸(C18∶1)含量线性相关程度极高,用C22∶1对C18∶1作图得到两者线性方程Y=-1.112 02X+64.536 83,相关系数为R=-0.988 1,P0.001,有非常显著的统计学意义。特征2:92.39%菜籽油的棕榈酸(C16∶0)值不超过4.5%。特征3:99.06%正常菜籽油的亚油酸(C18∶2)范围在11.8%~20.3%。可利用这3项特征指标对菜籽油脂肪酸组成是否合格进行综合判定,较GB/T 5539—2008 4.7和GB/T 1536—2004判定方法,能有效降低掺伪检出限。     

基于特征脂肪酸的掺伪芝麻油快速鉴别模型建立

脂肪酸是植物油中的主要营养成分,不同种类的食用油中所含的脂肪酸含量也不相同,本研究据此对芝麻油掺入大豆油、花生油、棉籽油的油样应用近红外光谱技术建立测定4 种脂肪酸含量的方法。以气相色谱法测定的脂肪酸含量作为化学值,校正集样品数为122,验证集样品数为38,结果表明：掺假芝麻油油样的亚麻酸
（C18∶3）、花生酸（C20∶0）、木焦油酸（C24∶0）和肉豆蔻酸（C14∶0）对近红外有特异吸收。分别建立4 种脂肪酸含量的模型,通过对模型进行优化,校正集样品的化学值与近红外的预测值的相关系数（R2）分别为R2（C18∶3）=0.989、R2（C20∶0）=0.995、R2（C24∶0）=0.993、R2（C14∶0）=0.996。验证集样品的化学值与近红外的预测值的R2分别为0.984、0.949、0.956、0.988。4 种脂肪酸含量的预测平均相对误差依次为6.0%、5.6%、4.4%、4.8%。     

杏仁油挥发性成分指纹图谱的构建及掺伪定量检测方法研究

以17种不同的杏仁油为原料,采用顶空固相微萃取(SPME)和气相色谱仪测定了其挥发性成分,建立了杏仁油挥发性成分指纹图谱,并采用向量夹角余弦法计算了指纹图谱相似度。结果表明,杏仁油挥发性成分指纹图谱由12个共有色谱峰构成,通过聚类分析和相似度分析,发现该指纹图谱重复性好,专属性强。在该方法的基础上,建立了菜籽油-杏仁油掺伪模型:Y=-2947.0X~3+1254.9X~2+77.661X+46.693(其中Y为菜籽油掺假比例%,X为夹角余弦cosθ),适用于掺伪量15%以上杏仁油的鉴别。     

基于特征脂肪酸变化对花生油掺伪快速鉴别方法研究

该实验采用近红外光谱与气相色谱相结合，通过对特征脂肪酸的含量变化，开展快速鉴别花生油掺伪的研究。以花生油中掺入不同比例菜籽油、棉籽油及大豆油作为掺伪样品，气相色谱法测得掺伪油样棕榈酸、硬脂酸、油酸、亚油酸和花生酸5种特征脂肪酸含量，使用近红外光谱测定其R—H基团在1 170、1 205、1 395、1 415 nm特征峰波长的变化，利用Unscrambler 10.4软件通过偏最小二乘判别法对脂肪酸含量与近红外光谱图峰位相拟合，建立一元回归线性方程。结果表明，掺伪花生油5种特征脂肪酸均有响应，棕榈酸对应的近红外光谱模型较好，校正集相关系数为0.997,校正均方根误差为0.014、交叉验证均方根误差为0.018。通过多种花生油进行验证，预测模型准确，对快速无损检测花生油具有重要意义。     

5种不同植物油脂氧化程度与脂肪酸比例变化的相关性研究

选取椰子油、大豆油、玉米油、葵花籽油、菜籽油5种植物油脂为研究对象,在180℃加热氧化的过程中,测定不同油脂中脂肪酸比例变化规律,与共轭二烯值(CDV)、p-茴香胺值(p-AV)和己醛含量进行相关性分析。结果表明:加热相同时间油脂的氧化程度与脂肪酸组成有显著性差异,含多不饱和脂肪酸油脂的氧化敏感性较高;对CDV、p-AV和己醛含量与脂肪酸比例之间相关性分析可知椰子油的SFA/UFA比例与CDV、p-AV和己醛含量相关性R值在0.9以上;大豆油、玉米油C18∶0/C18∶1,C18∶1/C18∶2脂肪酸比例与CDV、p-AV和己醛含量之间相关性R值在0.8以上,葵花籽油的C16∶0/C18∶2,C18∶0/C18∶2与CDV、p-AV和己醛含量之间的相关性在0.85以上,而菜籽油的脂肪酸比例C16∶0/C18∶1,C18∶0/C18∶1,C18∶1/C18∶2,SFA/UFA与CDV、p-AV和己醛含量之间的相关性R≥0.8。油脂中脂肪酸比例与油脂氧化指标的相关性研究表明,利用不同特征脂肪酸比例参数可以表征不同植物油脂的氧化程度,为油脂氧化研究提供参考。     

菜籽油中掺入大豆油后的鉴别方法初探

通过对不同菜籽油的亚油酸与油酸组分之比进行分析得出一个范围值,在加入不同量的大豆油后,对两组分比进行再次分析,根据比值确定掺入大豆油的量,最终确定较可靠的掺入大豆油的检出量。     

废工业棕榈油制备生物柴油的研究

利用固体酸作催化剂对酸值较高的废棕榈油进行预酯化,采用正交试验优化预酯化的工艺条件,最佳工艺条件是:反应温度为70 ℃,反应时间为4.0 h,固体酸催化剂的用量为3.0%,预处理后废棕榈油的酸值为2.18 mg KOH/g.研究了预酯化后的废棕榈油与甲醇进行的酯交换反应,得到最优工艺条件是:反应温度为65 ℃,反应时间为1.0 h,催化剂KOH的用量为1.0%,酯交换反应的转化率为96.85%,生物柴油总得率为93.2%.以废棕榈油为原料制备的生物柴油,除倾点较高外,其主要性能均符合柴油标准.     

Hypolipidemic effect of blends of coconut oil with soybean oil or sunflower oil in experimental rats

Blended oils, consisting of coconut oil with sunflower oil or soybean oil, were prepared (22–24% linoleic acid) to provide higher amounts of PUFA to coconut oil consumers. Animal experiments were carried out to find the effects of coconut oil blends, using weanling rats, by feeding native and blends of oils at 10% level in the diet for 60 days. Serum cholesterol levels were reduced by 5% and 21%, respectively, in rats given blended oils containing CNO/SFO and CNO/SBO while liver cholesterol did not show a significant change when rats were given blends in comparison with rats given CNO. Serum and liver lipid analyses also showed significant change in TG concentration in rats fed blended oils compared with rats given CNO. These studies indicated that the atherogenic potentials of a saturated fatty acid-rich CNO can be significantly decreased by blending with an oil rich in unsaturated lipids in appropriate amounts.     

Canarium zeylanicum seed oil: an edible oil with beneficial qualities

The quality parameters, fatty acid composition, phenolic compounds and antioxidant properties of the seed oil of Canarium zeylanicum were determined. The results indicate that the seed oil of Canarium zeylanicum is an excellent source of essential fatty acids which contains C18:2 (49.35 ± 0.35%) and C18:3 (19.09 ± 0.01%). The total phenol contents of the seed oil and the seed hull of Canarium zeylanicum were 66 ± 6 and 2014 ± 14 mg kg⁻¹respectively. The identified phenolic acids in the methanolic extracts of seed oil include 3,4-dihydroxybenzoic acid, p -hydroxybenzoic acid, vanillic acid and ellagic acid. Diphenyl-2-picrylhydrasyl radical scavenging activity, inhibition of deoxyribose degradation and the reducing power of the methanolic extracts of seed oil and seed hull of Canarium zeylanicum are comparable with those of butylated hydroxytoluene solutions.     

Chemical stability of extra-virgin olive oil added with oregano essential oil

Extra virgin olive oil is highly consumed and well known for its nutritional and health benefits. However, it is fatty food highly susceptible to lipid oxidation. The objective of this study was to evaluate the preserving effect of oregano (Origanum vulgare L. spp vulgare called "oregano compacto") essential oil on physical and chemical properties in extra virgin olive oil during storage. Oregano essential oil composition was analyzed by GC-MS. This essential oil was added into extra virgin olive oil at 0.05%. The samples were stored in 3 different conditions: darkness, light exposure, and temperature (60 °C). Chemical indicators of lipid oxidation (peroxide value, p-anisidine value, conjugated dienes, free fatty acidity, and carotenoid and chlorophyll contents) were measured. High content in carvomenthol (22.52%), terpinolene (19.77%), thymol (13.51%), and γ-terpinene (10.30%) were detected in oregano essential oil. Olive oil samples without oregano essential oil stored at 60 °C and exposure at artificial light had the highest peroxide values during storage. Higher p-anisidine and K232 values after day 7 of storage were detected in temperature, darkness, and light exposure treatments. Light treatment was the main factor that degraded chlorophyll causing loss of color. The highest chlorophyll content (3.87 mg/kg) was observed in olive oil with essential oil at the end of storage. In general, olive oil samples added with oregano essential oil had lower peroxide, conjugated dienes, and p-anisidine values and higher chlorophyll and carotenoid contents during storage. Oregano essential oil retards lipid oxidation process in olive oil prolonging its shelf life. PRACTICAL APPLICATION: Oregano essential oil was and is used with the purpose of flavoring and aromatizing food. This essential oil due to its composition has shown antioxidant activity. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are thought to be promoters of carcinogenesis. Extra virgin olive oil is widely consumed because of its nutritional benefits and sensory properties which are very important to be preserved in the product. In this study, the oregano essential oil showed remarkable antioxidant activity in olive oil. Therefore, this essential oil could be considered for the industry as natural antioxidant not only to be used in olive oil but also in other fatty food products to substitute synthetic ones.     

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.     

藻油及其与火麻仁油混合物辅助降血脂功能

研究了藻油及其与火麻仁油混合物的辅助降血脂作用。将84只SPF级雄性SD大鼠分为7组,其中6组喂养高脂高胆固醇饲料2周以建立高脂血症模型,造模成功后即进行4周干预实验,阴性对照组与模型组给予0.85％生理盐水,药物组每日灌胃3.33 mg/kg立普妥,混合物组每日灌胃800 mg/kg藻油混合物,藻油干预组每日分别灌胃150、300、600 mg/kg藻油。实验过程记录大鼠的体重、进食量与饮水量,实验结束后采集大鼠的血液、附睾脂肪、肝脏,检测大鼠的血脂四项血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C),并进行肝脏与附睾脂肪病理检测。结果表明：造模后高脂血症大鼠的TC、TG、LDL-C水平显著上升;中、高剂量藻油及其混合物均可使大鼠血清TC（混合物除外）、TG、LDL-C水平显著降低,藻油呈现剂量依赖;藻油及其混合物干预后大鼠肝脏中含脂滴的肝细胞和多灶性泡沫细胞聚集例数减少。说明藻油及其混合物对高脂高胆固醇饮食导致的肝细胞脂肪变性、脂肪堆积有一定改善作用,藻油及其混合物均有辅助降血脂作用。     

紫苏籽油与红花籽油联合使用降血脂研究

通过饲喂高脂饲料诱导建立小鼠高脂血症模型,研究紫苏籽油与红花籽油等质量混合后对高脂血症小鼠血脂水平的影响,并与市售紫苏油软胶囊作比较。结果表明,紫苏籽油和红花籽油等质量混合后可以极显著降低高脂血症小鼠的胆固醇(TC)、甘油三酯(TG)水平(p0.01)以及显著降低低密度脂蛋白胆固醇(LDL-C)含量(p0.05),能极显著升高总胆固醇中高密度脂蛋白胆固醇的比例(HDL-C/TC)(p0.01),极显著降低动脉硬化指数(AI)(p0.01);其与紫苏油软胶囊组比较,效果更好。