共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
本文介绍了用氧化镁吸收油热分解的制样方法,而后用能量色散X射线荧光分析法测定油中微量元素。该方法避免了复杂的基体效应校正,作者用此方法测定了油中七种元素,其探测限为几个μg/g。 相似文献
4.
5.
近代物理学为研究材料在超高压力下的物理性质,地震学与地球物理学为模拟地壳深层的高压状态,研制了几千、几万甚至几十万大气压的高压设备.在三或四万大气压以下,选用液体作传压介质.例如,石油醚、异戊烷等轻质矿物油,煤油、汽油等一般矿物油,来源于动植物的甘油、甲基或乙基硅油等高分子合成油,都可作为传压介质. 我们在一万大气压下试用过石油醚和变压器油的混合液.石油醚是石油分馏得到的低分子烃的混合物,主要是含碳链为C5和C6的戊烷、己烷.石油醚的最大缺点是易挥发、有气味、有麻醉性. 也可将煤油和变压器油按一定比例混合.煤油是石… 相似文献
6.
茶籽油油学性质的光谱分析研究 总被引:1,自引:0,他引:1
用气相色谱测定了思茅地区普洱茶果油中的脂肪酸的组成,并将其与花生油、菜籽油、油茶籽油、橄榄油中的脂肪酸组成进行了比较,发现普洱茶果油中油酸的质最分数高于花生油、菜籽油,低于油茶籽油、橄榄油,芥酸的质量分数低于花生油、菜籽油及油茶籽油,略高于橄榄油,故普洱茶果是一种理想的油料资源.用气-质联用从普洱茶果油挥发性物质中鉴定出30种化合物,其中大部分为醇、醛、酮、酯类物质,并且多数同时含有不饱和键,国内鲜见报道. 相似文献
7.
8.
9.
10.
11.
煎炸胡麻油分子光谱分析研究 总被引:2,自引:0,他引:2
为保证煎炸食品的安全,探索煎炸食用油变化的规律,该实验利用三维荧光结合紫外-可见吸收光谱研究了胡麻油不同煎炸时间的物理化学性质的变化.结果表明,胡麻油在煎炸的前2 h内,其物理化学性质没有明显的变化,但是当连续使用超过6 h以后,其荧光光谱与紫外吸收光谱都有较大变化,说明胡麻油在连续煎炸6 h后,其物理化学性质变化最为... 相似文献
12.
近红外光谱技术快速鉴别地沟油与食用植物油的研究 总被引:1,自引:0,他引:1
地沟油检测是我国食品安全最为关注的话题之一,它给人们的生活健康带来了极大的危害。国内现有的检测手段也仅停留在定性检测水平上,只能确定地沟油的有无,还难以进行定量检测。本实验利用近红外光谱技术与光纤传感技术相结合的新方法对勾兑混合油中地沟油的含量进行了定量分析。将煎炸老油与九三大豆油按照一定的体积比进行勾兑,共计50个样本,采集其近红外透射光谱,分别采用偏最小二乘法(PLS)和BP人工神经网络建立了煎炸老油含量的定量分析模型,校正集决定系数分别为0.908和0.934,验证集决定系数分别为0.961和0.952,均方估计残差(RMSEC)为0.184和0.136,预测均方根误差(RMSEP)都为0.111 6,符合应用要求,同时还结合主成分分析法(PCA)对煎炸老油与食用植物油进行了鉴别,识别准确率为100%。实验研究证明近红外光谱技术不仅可以准确快速的定性分析地沟油, 还能定量的检测地沟油的含量,在油脂的检测方面具有很大的应用前景。 相似文献
13.
储油岩芯二相液体吸附特性的NMR研究及应用 总被引:2,自引:1,他引:1
为研究储油岩芯对液体的吸附机理,我们特地用同一岩芯制成以下几种样品:(1)吸附不同量的煤油;(2)吸附不同量的水;(3)先吸附一定量的水再吸附一定量的煤油.对以上三组样品,做了NMR自旋—晶格弛豫时间测定;考查了岩芯样品中各弛豫成分量与液体吸附量的变化规律;得出了岩芯内水和煤油受束缚越紧其弛豫时间越短的结论.并依据大量石油地质学的结论建立了砂岩孔隙中油水二相系统的核磁共振模型. 相似文献
14.
地沟油特异性指标研究 总被引:1,自引:0,他引:1
精炼地沟油相比于食用植物油,经历了更长时间的高于200 ℃的高温历程,第三类地沟油或称煎炸老油也经历了长时间高温历程。本文应用ATR红外光谱法,研究了六种常用植物油中共轭脂肪酸甘油酯含量、反式脂肪酸甘油酯含量、不饱和度等三个指标值随加热温度及加热时间的变化情况,以期找出地沟油的特异性指标。研究结果表明: 从160 ℃开始,各植物油的共轭脂肪酸甘油酯含量及反式脂肪酸甘油酯含量随着加热温度升高及加热时间增长而增加,不饱和度则降低,当加热温度为200 ℃或以上、加热时间达到4 h或更长时,六种植物油的三个指标值有大幅变化。共轭脂肪酸甘油酯含量的变化幅度还与植物油中亚油酸含量有关,亚油酸含量越大其变化幅度越大;反式脂肪酸甘油酯含量变化幅度则还与植物油中油酸含量有关,油酸含量高者变化幅度大。此外,上述三个指标值与存储时间有关,随着六种植物油存放时间增长,共轭脂肪酸含量变大,不饱和度变小,而反式脂肪酸含量变化规律与高温长时间加热不同,其含量不是变大而是变小,保质期内三个指标值的变化幅度都小于经过高温长时间加热的变化幅度。因此,从三个指标值及其变化规律可以了解植物油是否经历了长时间高温历程,它们可以作为地沟油及精炼地沟油的特异性指标。 相似文献
15.
As a non-thermal processing method, the ultrasound treatment prior to the frying process has been demonstrated with great potential in reducing the oil absorption of fried food. This research aimed to evaluate the effect of ultrasound pretreatment on starch properties, water status, pore characteristics, and the oil absorption of potato slices. Ultrasound probe set with two power (360 W and 600 W) at the frequency of 20 kHz for 60 min was applied to perform the pretreatments. The results showed that ultrasound pretreatment led to the surface erosion of starch granules and higher power made the structure of starch disorganized. Moreover, the fraction of bound water and immobilized water were changed after ultrasonic pretreatment. Pores with the minor diameters (0.4–3 μm and 7–12 μm) were formed after ultrasound pretreatment. The penetrated surface oil (PSO) content, and structure oil (STO) content were reduced by 27.31% and 22.25% respectively with lower power ultrasound pretreatment. As the ultrasound power increased, the surface oil (SO) content and PSO content increased by 25.34% and 12.89% respectively, while STO content decreased by 38.05%. By using ultrasonic prior to frying, the quality of potato chips has been greatly improved. 相似文献
16.
César Jiménez-Sanchidrián 《应用光谱学评论》2016,51(5):417-430
Vegetable oils provide high nutritional value in the human diet. Specifically, extra virgin olive oil is one of the main ingredients of the Mediterranean diet, which is among the healthiest of eating practices. This article reviews the use of Raman spectroscopy for analyzing edible vegetable oils including olive oil. Although the spectra for edible vegetable oils are similar, they exhibit some differences which, however small, enable their discrimination. Thus, Raman spectra allow one to determine the degree of unsaturation of oils. This property is correlated with the iodine value but much faster and simpler to obtain. The degree of unsaturation can be used to classify and authenticate oils, which is especially useful with high-quality oils. In fact, adulteration with mixtures of more inexpensive oils can be easily detected by Raman spectroscopy. This technique additionally allows some minor components present in unsaponifiable matter to be identified. Fats in general and vegetable oils in particular, are prone to oxidation. Thus, double bonds in them are oxidized to form triglycerides. Vegetable oils are widely used for frying and Raman spectroscopy allows for their oxidative stability against heating at the usual frying temperatures to be assessed. 相似文献
17.
有气流扰动下管流油水混合物粘度实验测量与计算模型 总被引:2,自引:0,他引:2
采用局部即时取样方法对水平管内油气水三相流动情况下各种混合比例的复杂混合物的流动粘度进行了实验研究,实验工质采用46号机械油、自来水和空气。以实验数据为基础提出了考虑流动参数变化影响的反相点预测关联式。考虑到管内油水两相的混合发展过程,以局部即时取样的实验数据为基础,提出了一个气流扰动下管内流动条件下油水混合物粘度的预测关系式,该模型考虑了油水两相本身的物性以及流动因素的影响。指出考虑流动参数影响的粘度预测模型能大大提高油气水三相流动情况下油水混合物实测粘度的预测精度。 相似文献
18.
应用核磁共振时域二维弛豫相关谱分析的方法,对玉米胚芽的核磁共振弛豫特性进行了研究.对以下三种样品进行了测定:(1)胚芽不含油(用化学方法蒸馏出)但是含有不同百分含量的水;(2)胚芽不含水(真空蒸发)但是含有不同百分含量的油;(3)含有不同百分含量的水的胚乳水系统.研究表明随着水含量的增加水的纵向弛豫时间T1减小,表明水与胚芽基质具有强烈的相互作用,而油的纵向弛豫时间T1随着油含量的增加变化很小,表明油与胚芽基质之间没有大的相互作用,油几乎独立地处在胚芽中;对低水分(少于5%)玉米胚芽水系统,结果表明水是束缚于胚芽基质上,而油则是以油胞的形式存在于胚芽中.在玉米胚芽水系统中有两个T1弛豫成分,长T1弛豫成分从基质到水的交换率为57s-1;从水到基质的交换率为113s-1.短T1成分从基质到水的交换率为245s-1;从水到基质的交换率为821s-1.在低水合状态下,胚乳水系统仅有一个T1弛豫成分.胚乳到水的交换率高于37s-1. 相似文献
19.
Dyneshwar Ghayal Aniruddha B. Pandit Virendra K. Rathod 《Ultrasonics sonochemistry》2013,20(1):322-328
The present work demonstrates the application of a hydrodynamic cavitation reactor for the synthesis of biodiesel with used frying oil as a feedstock. The synthesis involved the transesterification of used frying oil (UFO) with methanol in the presence of potassium hydroxide as a catalyst. The effect of geometry and upstream pressure of a cavitating orifice plate on the rate of transesterification reaction has been studied. It is observed that the micro level turbulence created by hydrodynamic cavitation somewhat overcomes the mass transfer limitations for triphasic transesterification reaction. The significant effects of upstream pressure on the rate of formation of methyl esters have been seen. It has been observed that flow geometry of orifice plate plays a crucial role in process intensification. With an optimized plate geometry of 2 mm hole diameter and 25 holes, more than 95% of triglycerides have been converted to methyl esters in 10 min of reaction time with cavitational yield of 1.28 × 10?3 (Grams of methyl esters produced per Joule of energy supplied). The potential of UFO to produce good quality methyl esters has been demonstrated. 相似文献